Recent Trends in High Efficiency Induction Motor Drives

1. Introduction

1.1. Market Size of Electrical Drives

The demand for Electric Drives (ED) across various industrial sectors and applications is growing. Owing to the latest published reports [1], the global market size for ED is estimated at USD 25.51 billion in 2024, while it is expected to reach USD 32.70 billion by 2029, growing at a compound annual growth rate (CAGR) of 5.10% during the period 2024 to 2029 [1].

Meanwhile, the global market size of AC drives accounts for an estimated value of USD 17.9 billion in 2022 and is projected to reach USD 25 billion by 2028, at a compound annual growth of 5.7 % [2]. Figure 1 and Figure 2 indicate the global market size of electrical drives and AC drives respectively.

1.2. Electric Drives and UN-SDGs

During the last decade, the demand for efficient electric drives (ED) has increased significantly to reduce energy consumption and to enhance environmental conservation in accordance with the sustainable development goals (SDGs) of united nations (UN), and directly linked to the goals: 7, 9, and 13 which are related to energy efficiency, sustainable & clean industries, and climate action to reduce greenhouse gas emissions respectively. Owing to the latest published reports [3,4] significant acceleration is still needed to meet the target.

Therefore, high efficiency AC drives play a considerable role in tackling some of the world’s greatest challenges, achieving a sustainable and equitable future. The high efficiency drives are characterized by minimum energy consumption and a significant energy saving, which results in less fuel consumption and a significant reduction in carbon emissions. These positive consequences support the transition to more sustainable energy use, aligning with the UN-SDGs goals. The wide spread of these high efficiency drives promotes the development of more eco-friendly technologies, enhancing energy efficiency across various sectors. As mentioned before, the utilization of high efficiency electric drives helps mitigate greenhouse gas emissions, contributing to global efforts to limit global warming [5,6].

This paper presents the state-of-the art advancements in induction motor drives, including high efficiency electric motors, low power losses power semiconductor devices, and control techniques of the power electronic converters that essentially contribute to improving overall drive efficiency in accordance with energy efficiency guidelines and standards.

1.3. Elements of a Typical EDS

The generalized block diagram of a typical electric drive system (EDS) is illustrated in Figure 3. A typical EDS is composed of the following elements: mechanical load, electric motor, power source, power Electronic converter (power conditioner), control unit, and measuring Devices (sensors and transducers).

Simply, the main objective of an EDS is to drive a mechanical load at any desired speed/position and torque requirements using an electric motor that is fed from a power source through a proper power electronic converter. The high-performance EDS operates in closed loop mode such that the motor can run at the desired speed apart from the load variation or any transient variations in the input voltage that feeds the EDS [7].

Practically, the block diagram of the high efficiency EDS is like the conventional EDS. The major differences between both systems are considered in the following points:

1- Efficiency classes of the electric motor, where high efficiency and premium efficiency classes are employed.

2- Types of the power semiconductor devices that form the power electronic converter, where high efficiency converter that offers minimum power losses are utilized.

3- Control techniques which can involve energy saving algorithm or it can guarantees the operation at optimum flux level for a wide range of motor speed.

1.4. Factors Affecting Efficiency of IM Drives

The key factors that affect directly the overall efficiency of the IM drives are related mainly to motor design, operating conditions, and environmental conditions, periodic checkup rate and maintenance status. The breakdown of these factors are summarized in Table 1 as follows:

1.5. Power Losses in IM Drives

Previously mentioned factors of Table 1 can be optimized to achieve a high efficiency AC drive. Practically, corresponding items of Table 1 contribute to various power losses across the elements of the AC drive, which altogether affects the overall efficiency of the IM drive. Accordingly, the main types of the power losses in IM drives can be summarized in the following points:

1-

Copper losses across the motor windings.

2-

Magnetic (iron) losses of the magnetic circuit.

3-

Losses in rotor windings (in case of wound rotor) or cage losses (in case of squirrel cage).

4-

Iron losses or core losses including hysteresis and eddy currents losses.

5-

Mechanical and bearing losses due to friction.

6-

Stray losses due to leakage flux, magnetic imperfections.

7-

Switching power losses of the inverter.

8-

Conduction power losses of the inverter.

9-

Cooling system losses due fans (forced air), liquid cooling and heat sink thermal resistance.

10-

Inverter driving circuits power losses.

11-

Snubber circuits and passive filters power losses.

Thus, minimization of all these types of losses by optimum design of the AC motors, utilizing efficient power semiconductor devices, optimizing the drive cooling and adopting proper control strategy permits considerable energy saving and enhances the overall efficiency of the electric drive system.

1.6. Advancement Directions in IM Drives

The advancement in IM drives has many directions. The major trends includes:

1- Replacement of conventional IM motors by high efficiency and premium grades counterparts [8,9].

2- Utilization of wide bandgap (WBG) semiconductors[10,11].

3- Implementation of modern control techniques such as: direct torque control (DTC) proposed by authors of [12], model predictive control (MPC) [13], and incorporation of regenerative braking and energy saving algorithms to reduce energy consumption [14,15].

4- Utilization of efficient high speed digital signal processors (DSP) as core processors [16], and involvement of Hardware in the loop (HIL) data acquisition cards for rapid prototyping and testing purposes [17,18].

Addressing and discussions of such directions are presented in sections 2 to 5 as follows: Section 2 provides state-of-the-art advancement in high efficiency induction motors that are commonly used in IM drives. In fact, induction motors are only considered in this article to limit the study and the article length. Section 3 addresses the major trend in high efficiency power electronic converters based on (WBG) semiconductor devices. Section 4 presents an overview of the advanced control techniques utilized to achieve high performance IM drives. Section 5 highlights key manufacturers of induction motor drives and the employed control techniques.

2. High-Efficiency Induction Motors

In general, motor design plays an important role in achieving higher efficiency [19,20]. Several types of AC motor are commonly used and employed in modern electric drive systems. Thus, obtaining high-efficiency AC drives depends on utilization of high efficiency AC motors. Induction motors (IMs) are considered the most important rotating machines that remain widely used in the modern industry due to their simplicity and reliability.

2.1. Main Features of High Efficiency IMs

Compared with the standard types of 3-F induction motors whose cross section of their stator is illustrated in Figure 4, and the rotor of squirrel case types is depicted in Figure 5, the high efficiency counterparts have the following features:

1-

Longer core (motor) length.

2-

Thinner core lamination.

3-

High grade core material such as grain oriented silicon steel.

4-

Wider stator slots with optimized shapes (based on Finite Element design and analysis).

5-

Thicker stator windings (larger winding cross section area).

6-

High Temperature electrical insulation class.

7-

Larger rotor diameter.

8-

Lower resistance rotor bars such as die cast copper rotor.

9-

Narrower air gap between stator and rotor.

10-

Larger fan size with optimized aerodynamic.

11-

Larger cooling fins and increase cooling surface area.

12-

Small bearing size with lower friction losses.

13-

Anti corrosion coating for the motor body.

Due to the importance of the topic, several research efforts have been exerted during this decade to improve the performance of IMs in terms of minimizing the power losses, improving the starting characteristics, or adopting new approaches for design optimization, development of bearingless motors for high speed applications. Recent improvements in rotor designs and stator winding configurations have led to significant efficiency gains [21,22,23].

2.2. Research Contributions Related to High Efficiency IMs

A summary of the major research contributions in high efficiency IMs during the period (2017-2024) are presented in Table 2, Table 3, Table 4, Table 5 and Table 6. The survey of core contributions includes the following main areas:

1-

Design and manufacturing of high and premium efficiency induction motors [Table 2].

2-

Optimization techniques and algorithms for high efficiency motor design [Table 3].

3-

Efforts in bearingless IMs [Table 4].

4-

Modeling, loss analysis and computational tools [Table 5].

5-

Thermal analysis and cooling systems [Table 6].

Moreover, the efficiency ranges of typical premium efficiency IMs, fabricated by key manufacturers for different power ratings, are presented in [Table 7].

Table 7 summarizes the corresponding efficiency ranges of typical premium efficiency IMs fabricated by different manufacturers [103,104,105,106,107]. For power rating between 0.75 kW and 22 kW, the corresponding efficiencies are between 82.5 % and 93.6 %. While for higher power rating between 30 kW and 110 kW, the corresponding efficiencies are between  93.6 % and 95.8 %.

3. Wide-Bandgap (WBG) Power Semiconductor Devices

The transition from silicon (Si)-based semiconductor devices to wide-bandgap (WBG) semiconductors devices is considered one of the most significant advancements in improving the overall efficiency of the power electronic converters [108,109]. Basically, the band gap is defined as the minimum energy required to excite electrons, transferring the electrons from the valence band to the conduction band.

3.1. Characteristics of WBG Semiconductors

Compared to the conventional Si-based semiconductors, the WBG semiconductors have a larger (wider) bandgap, approximately three times wider. As illustrated in Fig 6, where WBG semiconductors (SiC and GaN) have band gap between 3.3 eV and 3.4 eV, allowing the WBG power devices to withstand higher voltages (high breakdown voltage) due to the direct correlation between the band gap and the critical breakdown (electric) field of a semiconductor. As a typical values, the critical electric field of WBGs semiconductors is approximately ten times greater than that of Si semiconductors (0.3 MV/cm in Si, 3.5 MV/cm in SiC and 3.3 MV/cm in GaN). Consequently, the breakdown voltage in WBG devices is higher than that of conventional Si devices.

Figure 6. Simplified Energy Diagram and Band Gap Energy of Si, WBG, and Insulators.

Figure 6. Simplified Energy Diagram and Band Gap Energy of Si, WBG, and Insulators.

However, there are some main differences in several characteristics of SiC and GaN that let each type more convenient and adequate for certain applications rather that the other. E.g., GaN has higher electron mobility compared with SiC (GaN:1500 cm2/Vs, Sic: 900 cm2/Vs). This makes GaN devices characterized by high switching frequencies, which makes them more suitable for high frequency applications.

Meanwhile, the greater thermal conductivity of SiC devices (5 W/cmK) compared with that of than GaN (1.3 W/cmK) makes SiC devices transfer heat more efficiently, enabling operation at higher temperature and allowing higher power densities as well. Thus, the distinct characteristics of each type of WBG devices make GaN suitable for low-power and high-frequency applications, while they make SiC suitable for high-power and high-voltage applications [110,111]. Compared to traditional Si-based devices, WBG devices offer superior performance in terms of higher switching frequencies, lower power losses and high temperature capability. These advantages have permitted their utilization in various applications such as high performance industrial drives [112,113]; electric vehicle (EV) [114,115], aircraft propulsion [116], and renewable energy applications [117,118]. The utilization of SiC power devices in motor drives can reduce the overall cost of the drive by decreasing the size of passive components[119,120].

3.2. Main Challenges and Design Issues

Compared with the Si power devices, the WBG power devices face some obstacles and challenges that limit their industrial utilization and delay achieving commercial acceptance and full satisfaction. Some of these challenges are:

1- Higher fabrication and manufacturing cost.

2- Complex fabrication processes to have the final product with good quality.

3- Reliability issue for GaN devices at high temperature.

4- Cooling system design and analysis.

5- Requirement of proper packaging to alleviate electromagnetic interference (EMI).

Fortunately, the fabrication costs of SiC devices are expected to decline as companies move toward the technology of six-inch wafers [120].

Several design issues are taken into consideration during design and testing of WBG-based power electronic converters to achieve successful and reliable operation. The main important design issues that are related directly to the successful and reliable operation of the WBG-based power electronic converter are:

1- Gate driving signals (voltage levels), which are different from the well-known and commonly used values of Si devices.

2- Effect of parasitic inductance at operation of high switching frequencies. It requires compact and optimized PCB deigns.

3- EMI and electromagnetic compatibility (EMC) concerns due to high dv/dt and di/dt.

3.3. Research Contributions Related to WBG-Based Converters and AC Drives

A summary of the major research contributions is presented in Table 8, Table 9, Table 10 and Table 11. The survey of core contributions includes the following main areas:

1- Performance analysis of WBG devices, inverters and IM drives [Table 8].

2- System design and performance improvement [Table 9].

3- Thermal management and cooling systems [Table 10].

4- Key challenges and solutions [Table 11].

Moreover, state-of-the-art ratings and main manufacturers of SiC-Base MOSFET power transistors, as one of the WBG power semiconductor devices, are summarized in Table 12.

Table 8. Research Contributions related to Performance Analysis of WBG Devices and Systems.

Main areaBREAKPerformance Analysis	Ref.	Core contribution
	[11]	Investigating the effects of high switching speeds and frequencies in wide-bandgap (WBG) motor drives on electric machines. It identifies increased motor overvoltage at terminals and stator neutral, leading to higher insulation stress and bearing currents.
	[109]	Proposing a hybrid DC–AC topology combining a Si-IGBT master unit with selective harmonic elimination PWM and a partial-power SiC-MOSFET slave unit. This configuration enhances efficiency, reduces switching loss, and improves power density.
	[110]	Providing comparative analysis of two-level and three-level SiC-based AC drive topologies for efficiency, voltage quality, and common-mode currents. It experimentally evaluates the impact of filters on mitigating high-frequency effects and meeting NEMA standards.
	[111]	Discussing issues such as EMI, high dv/dt, and insulation stress in case of WBG-based AC drives. Also, it addresses converter design trade-offs of WBG-based AC drives.
	[114]	Quantitative evaluation of energy savings and loss characteristics when replacing Si-IGBTs with SiC-MOSFETs in railway traction inverters.
	[115]	Introducing a figure-of-merit (FOM) for comparing 600/650V SiC and GaN semiconductors employed for EV drives. The paper reveals SiC's suitability for high-temperature, low-frequency applications and GaN's efficiency in high-frequency applications.
	[117]	Reviewing the state-of-the-art SiC power devices, including SiC-MOSFETs and SiC-SBDs, emphasizing their superior characteristics for power electronics applications.
	[118]	The paper introduces a novel integration of (SiC) devices with high-frequency transformers for high-power renewable energy applications. It designs and validates various DC-DC converter topologies with integrated SiC technology, achieving high efficiency (>98%), reduced size, and improved thermal management.
	[119]	Introducing a variable switching frequency PWM strategy to achieve zero-voltage switching in AC motor drives powered by two paralleled SiC inverters. The scheme improves reliability and energy efficiency of AC motor drives.
	[122]	Analyzing the voltage distribution in stator windings of WBG-based inverter-fed motors, highlighting the anti-resonance phenomenon as a critical cause of peak voltage stress near the neutral point.
	[125]	Providing a comprehensive review of hybrid Si/SiC switches, highlighting their potential to combine the advantages of silicon IGBTs and silicon carbide MOSFETs for high-efficiency, high-power-density energy conversion.
	[126]	Addressing a historical overview of silicon carbide (SiC) power devices. It discusses the commercialization of SiC devices, their adoption across various applications, and offers insights into future developments in the field.
	[127]	Presenting an analytical model to predict low-frequency radiated electromagnetic interference (EMI) in three-phase motor drive systems utilizing silicon carbide (SiC) MOSFETs. It models EMI noise sources in the time domain under varying voltage and current conditions, enabling accurate EMI prediction and compliance with EMI standard.
	[128]	Introducing an enhanced method for analyzing parasitic elements in high-performance silicon carbide (SiC) power modules. The study accurately characterizes parasitic impedances, leading to improved design and performance of SiC power modules.
	[129]	Evaluating high-power silicon carbide MOSFET modules against silicon insulated-gate bipolar transistor modules. It highlights SiC-MOSFETs' superior voltage blocking and faster switching capabilities, which enhance efficiency and performance.
	[130]	Presenting a switching loss model for silicon carbide (SiC) power MOSFETs, incorporating parasitic components to predict losses in high-frequency applications. The model validation accounts for the discharge and charge of the output capacitance.
	[131]	Studying and assessing the performance of an advanced-neutral-point-clamped (ANPC) converter configuration comprising two SiC MOSFETs and four Si IGBTs per phase leg, focusing on high switching frequency operations.
	[132]	Investigating the integration of wide-bandgap (WBG) devices into the DC/DC converters of EVs. A comprehensive model is developed to compare WBG-based converters with traditional silicon counterparts, highlighting performance improvements in EV applications.BREAK

Table 8. Research Contributions related to Performance Analysis of WBG Devices and Systems.

Main areaBREAKPerformance Analysis	Ref.	Core contribution
	[11]	Investigating the effects of high switching speeds and frequencies in wide-bandgap (WBG) motor drives on electric machines. It identifies increased motor overvoltage at terminals and stator neutral, leading to higher insulation stress and bearing currents.
	[109]	Proposing a hybrid DC–AC topology combining a Si-IGBT master unit with selective harmonic elimination PWM and a partial-power SiC-MOSFET slave unit. This configuration enhances efficiency, reduces switching loss, and improves power density.
	[110]	Providing comparative analysis of two-level and three-level SiC-based AC drive topologies for efficiency, voltage quality, and common-mode currents. It experimentally evaluates the impact of filters on mitigating high-frequency effects and meeting NEMA standards.
	[111]	Discussing issues such as EMI, high dv/dt, and insulation stress in case of WBG-based AC drives. Also, it addresses converter design trade-offs of WBG-based AC drives.
	[114]	Quantitative evaluation of energy savings and loss characteristics when replacing Si-IGBTs with SiC-MOSFETs in railway traction inverters.
	[115]	Introducing a figure-of-merit (FOM) for comparing 600/650V SiC and GaN semiconductors employed for EV drives. The paper reveals SiC's suitability for high-temperature, low-frequency applications and GaN's efficiency in high-frequency applications.
	[117]	Reviewing the state-of-the-art SiC power devices, including SiC-MOSFETs and SiC-SBDs, emphasizing their superior characteristics for power electronics applications.
	[118]	The paper introduces a novel integration of (SiC) devices with high-frequency transformers for high-power renewable energy applications. It designs and validates various DC-DC converter topologies with integrated SiC technology, achieving high efficiency (>98%), reduced size, and improved thermal management.
	[119]	Introducing a variable switching frequency PWM strategy to achieve zero-voltage switching in AC motor drives powered by two paralleled SiC inverters. The scheme improves reliability and energy efficiency of AC motor drives.
	[122]	Analyzing the voltage distribution in stator windings of WBG-based inverter-fed motors, highlighting the anti-resonance phenomenon as a critical cause of peak voltage stress near the neutral point.
	[125]	Providing a comprehensive review of hybrid Si/SiC switches, highlighting their potential to combine the advantages of silicon IGBTs and silicon carbide MOSFETs for high-efficiency, high-power-density energy conversion.
	[126]	Addressing a historical overview of silicon carbide (SiC) power devices. It discusses the commercialization of SiC devices, their adoption across various applications, and offers insights into future developments in the field.
	[127]	Presenting an analytical model to predict low-frequency radiated electromagnetic interference (EMI) in three-phase motor drive systems utilizing silicon carbide (SiC) MOSFETs. It models EMI noise sources in the time domain under varying voltage and current conditions, enabling accurate EMI prediction and compliance with EMI standard.
	[128]	Introducing an enhanced method for analyzing parasitic elements in high-performance silicon carbide (SiC) power modules. The study accurately characterizes parasitic impedances, leading to improved design and performance of SiC power modules.
	[129]	Evaluating high-power silicon carbide MOSFET modules against silicon insulated-gate bipolar transistor modules. It highlights SiC-MOSFETs' superior voltage blocking and faster switching capabilities, which enhance efficiency and performance.
	[130]	Presenting a switching loss model for silicon carbide (SiC) power MOSFETs, incorporating parasitic components to predict losses in high-frequency applications. The model validation accounts for the discharge and charge of the output capacitance.
	[131]	Studying and assessing the performance of an advanced-neutral-point-clamped (ANPC) converter configuration comprising two SiC MOSFETs and four Si IGBTs per phase leg, focusing on high switching frequency operations.
	[132]	Investigating the integration of wide-bandgap (WBG) devices into the DC/DC converters of EVs. A comprehensive model is developed to compare WBG-based converters with traditional silicon counterparts, highlighting performance improvements in EV applications.BREAK

Table 8. Research Contributions related to Performance Analysis of WBG Devices and Systems (Continued).

Performance Analysis	[133]	Examining the efficiency gains of integrating Silicon Carbide (SiC) MOSFETs into traction inverters for urban E-Buses. It evaluates whether these efficiency improvements can offset the higher costs of SiC devices, providing insights into the economic viability of adopting SiC technology in E-Transportations. According to the study, a significant energy savings can be gained when the vehicle operates mostly in the partial load area.
	[134]	Carrying out a simulation and measurement-based analysis of efficiency improvements achieved by retrofitting a 400 V, 300 kW automotive traction inverter with (SiC) MOSFETs. The results refer to a considerable reduction in inverter power losses by approximately 50% compared to traditional silicon IGBT-based counterpart.
	[135]	Developing an analytical model to assess voltage distortions in (SiC) MOSFET-based inverters for EVs, considering factors like voltage drops, dead time, and switching delays. Experimental results indicate that SiC-based systems exhibit lower voltage distortion and higher efficiency compared to traditional Si IGBT-based scheme.
	[136]	Performance assessment of a (GaN) devices, in an E-Traction drive system for electric vehicles. the study demonstrates that GaN-based inverters enhance efficiency and dynamic response compared to traditional Si-based inverters.
	[137]	Holding comparison of power and energy losses in 3-phase inverters using two (SiC) MOSFET modules and one Si (Si-IGBT) module. It considers factors like blanking time and reverse conduction and thermal feedback drive cycles.
	[138]	Providing a comprehensive overview of applying Finite Element Analysis (FEA) to the packaging of (SiC) power devices., addressing how (FEA) can be utilized to simulate and optimize the thermal, mechanical, and electrical performance of SiC power modules.

Table 8. Research Contributions related to Performance Analysis of WBG Devices and Systems (Continued).

Performance Analysis	[133]	Examining the efficiency gains of integrating Silicon Carbide (SiC) MOSFETs into traction inverters for urban E-Buses. It evaluates whether these efficiency improvements can offset the higher costs of SiC devices, providing insights into the economic viability of adopting SiC technology in E-Transportations. According to the study, a significant energy savings can be gained when the vehicle operates mostly in the partial load area.
	[134]	Carrying out a simulation and measurement-based analysis of efficiency improvements achieved by retrofitting a 400 V, 300 kW automotive traction inverter with (SiC) MOSFETs. The results refer to a considerable reduction in inverter power losses by approximately 50% compared to traditional silicon IGBT-based counterpart.
	[135]	Developing an analytical model to assess voltage distortions in (SiC) MOSFET-based inverters for EVs, considering factors like voltage drops, dead time, and switching delays. Experimental results indicate that SiC-based systems exhibit lower voltage distortion and higher efficiency compared to traditional Si IGBT-based scheme.
	[136]	Performance assessment of a (GaN) devices, in an E-Traction drive system for electric vehicles. the study demonstrates that GaN-based inverters enhance efficiency and dynamic response compared to traditional Si-based inverters.
	[137]	Holding comparison of power and energy losses in 3-phase inverters using two (SiC) MOSFET modules and one Si (Si-IGBT) module. It considers factors like blanking time and reverse conduction and thermal feedback drive cycles.
	[138]	Providing a comprehensive overview of applying Finite Element Analysis (FEA) to the packaging of (SiC) power devices., addressing how (FEA) can be utilized to simulate and optimize the thermal, mechanical, and electrical performance of SiC power modules.

Table 9. Research Contributions related to System Design of WBG-based Systems.

Main areaBREAKSystem DesignBREAKand performance improvement	Ref.	Core contribution
	[108]	Providing a comprehensive review of thermal design strategies for SiC power modules in EV motor drives. It emphasizes innovative heat sink optimization techniques and advanced simulation methods to enhance heat dissipation.
	[112]	Developing a highly integrated dv/dt filter design for silicon carbide (SiC) inverters, combining inductors, capacitors, and damping resistors directly into the bus bars. This approach reduces filter size and weight while maintaining compliance with NEMA standards, providing efficient motor protection against high dv/dt transients and voltage overshoots.
	[113]	Holding comparison of 2L SiC MOSFET and 3L Si IGBT (NPC and T-NPC) inverters for high-speed drives with long cables. It evaluates efficiency, overvoltage, heat sink design, and cost under same conditions. It addresses the trade-offs between SiC’s high efficiency at low power and IGBT’s cost-effectiveness advantage.
	[116]	Design and implementation of a Si/SiC hybrid five-level active neutral point clamped inverter for electric aircraft propulsion. It combines low-frequency Si switches and high-frequency SiC devices. A high performance hybrid modulation strategy is verified experimentally.
	[121]	Introducing a soft-switching voltage slew-rate profiling approach for SiC-based motor drives to mitigate motor overvoltage caused by the reflected wave phenomenon. By optimizing the rise/fall time of the output voltage to match the cable anti-resonance period, motor overvoltage is eliminated.
	[122]	Developing a multi-conductor transmission line model to identify significant stress near the neutral point. It helps mitigating insulation failure by managing anti-resonance effects in motor designs.

Table 9. Research Contributions related to System Design of WBG-based Systems.

Main areaBREAKSystem DesignBREAKand performance improvement	Ref.	Core contribution
	[108]	Providing a comprehensive review of thermal design strategies for SiC power modules in EV motor drives. It emphasizes innovative heat sink optimization techniques and advanced simulation methods to enhance heat dissipation.
	[112]	Developing a highly integrated dv/dt filter design for silicon carbide (SiC) inverters, combining inductors, capacitors, and damping resistors directly into the bus bars. This approach reduces filter size and weight while maintaining compliance with NEMA standards, providing efficient motor protection against high dv/dt transients and voltage overshoots.
	[113]	Holding comparison of 2L SiC MOSFET and 3L Si IGBT (NPC and T-NPC) inverters for high-speed drives with long cables. It evaluates efficiency, overvoltage, heat sink design, and cost under same conditions. It addresses the trade-offs between SiC’s high efficiency at low power and IGBT’s cost-effectiveness advantage.
	[116]	Design and implementation of a Si/SiC hybrid five-level active neutral point clamped inverter for electric aircraft propulsion. It combines low-frequency Si switches and high-frequency SiC devices. A high performance hybrid modulation strategy is verified experimentally.
	[121]	Introducing a soft-switching voltage slew-rate profiling approach for SiC-based motor drives to mitigate motor overvoltage caused by the reflected wave phenomenon. By optimizing the rise/fall time of the output voltage to match the cable anti-resonance period, motor overvoltage is eliminated.
	[122]	Developing a multi-conductor transmission line model to identify significant stress near the neutral point. It helps mitigating insulation failure by managing anti-resonance effects in motor designs.

Table 9. Research Contributions related to System Design of WBG-based Systems (Continued).

System DesignBREAKand performance improvement	Ref.	Core Contribution
	[123]	Providing design and implementation of a 500kW air-cooled Silicon Carbide (SiC) three-phase inverter. It achieves a record-breaking power density of 1.246MW/m³ and efficiency of 98.74%.
	[124]	Introducing a high-efficiency energy conversion system topology for 100 kW DC-DC power conversion using a 3.3 kV SiC device, achieving over 99.7% efficiency.
	[139]	Presenting a compact power module that combines Si-IGBTs and SiC-MOSFETs. The paper provides detailed gate driver designs and packaging solutions, offering guidelines for application-specific implementations.
	[140]	addressing the challenge of motor overvoltage oscillations in silicon carbide (SiC)-based motor drives. A quasi-three-level PWM scheme is proposed. This technique allows voltage reflections along the cable to settle before the voltage reaches its final value, eliminating motor overvoltage oscillations in cable-fed drives.
	[141]	Proposing a cost-effective packaging methodology for high-power (SiC) intelligent power modules (IPMs) by repackaging discrete SiC devices, aiming to meet the growing demand for high-current SiC power modules in EV applications.
	[142]	Introducing an optimized dead-time adjustment method for inverters utilizing an enhanced switching model of (GaN)-High Electron Mobility Transistors, reducing power losses and enhancing inverter efficiency.
	[143]	Presenting a (SiC)-based battery charger for plug-in EVs. The design attenuates the 2nd order ripple power, enabling the use of smaller DC-link capacitors, reducing the system volume and cost.
	[144]	Investigating a design methodology for inverter-side resistor-inductor (RL) filters aimed at mitigating motor overvoltage in (SiC)-based drives. The employed approach effectively addresses issues arising from impedance mismatches between inverters and motors.
	[145]	Developing a 10 kV (SiC) MOSFET power module. This configuration reduces parasitic inductances and capacitances, leading to a 53% increase in partial discharge inception voltage and a 90% reduction in common-mode current, enhancing high-voltage performance.
	[146]	Presenting a method to achieve zero switching loss in (SiC) MOSFETs by employing zero-voltage switching (ZVS), thereby minimizing thermal limitations, and enabling operation at higher switching frequencies.
	[147]	Designing a system-level tool that optimizes the power density of 3-phase, two-level SiC-based inverters. The developed design tool predicts a 159 % power density increase over Si-based inverters.
	[148]	Investigating the integration of (WBG) semiconductor devices, into renewable energy systems and smart grids. Some circuit design requirements to maximize the advantages of (WBG) have been addressed. Moreover, the merits such as the efficiency and power density enhancement have been discussed as well.
	[149]	Addressing crosstalk and voltage oscillations in (SiC) MOSFET half-bridge converters by proposing a gate driver that generates a negative turn-off voltage without a negative power supply. It presents a simple snubber circuit to suppress the parasitic ringing. The findings confirm the effectiveness of the presented solutions to enhance the converter performance.
	[150]	Designing a high-power converter based on (SiC) device, reducing conduction losses, and enhances efficiency, which is suitable for applications requiring compact and efficient power conversion solutions.
	[151]	Investigating a half-bridge gate driver circuit for (SiC) MOSFETs. The topology significantly reduces the total switching power losses by approximately 55% compared to conventional voltage source gate drivers, enhancing the converter efficiency.
	[152]	Introducing an inductor-less dv/dt filter for 100 kW to 1 MW voltage source converters using (SiC) devices. The design eliminates bulky filter inductors.
	[153]	Presenting a design methodology for dv/dt filters tailored to (SiC)-based inverters in high-frequency motor-drive systems. Thermal and electrical constraints have been addressed to mitigate insulation stress on motor stator windings caused by high slew rates in line voltages.
	[154]	Exploring the integration of (WBG) semiconductors, specifically into variable speed drive inverters. It introduces a soft-switching modulation scheme. The study also evaluates low-voltage (GaN) devices in multi-level inverter structures to enhance the overall efficiency.BREAK

Table 9. Research Contributions related to System Design of WBG-based Systems (Continued).

System DesignBREAKand performance improvement	Ref.	Core Contribution
	[123]	Providing design and implementation of a 500kW air-cooled Silicon Carbide (SiC) three-phase inverter. It achieves a record-breaking power density of 1.246MW/m³ and efficiency of 98.74%.
	[124]	Introducing a high-efficiency energy conversion system topology for 100 kW DC-DC power conversion using a 3.3 kV SiC device, achieving over 99.7% efficiency.
	[139]	Presenting a compact power module that combines Si-IGBTs and SiC-MOSFETs. The paper provides detailed gate driver designs and packaging solutions, offering guidelines for application-specific implementations.
	[140]	addressing the challenge of motor overvoltage oscillations in silicon carbide (SiC)-based motor drives. A quasi-three-level PWM scheme is proposed. This technique allows voltage reflections along the cable to settle before the voltage reaches its final value, eliminating motor overvoltage oscillations in cable-fed drives.
	[141]	Proposing a cost-effective packaging methodology for high-power (SiC) intelligent power modules (IPMs) by repackaging discrete SiC devices, aiming to meet the growing demand for high-current SiC power modules in EV applications.
	[142]	Introducing an optimized dead-time adjustment method for inverters utilizing an enhanced switching model of (GaN)-High Electron Mobility Transistors, reducing power losses and enhancing inverter efficiency.
	[143]	Presenting a (SiC)-based battery charger for plug-in EVs. The design attenuates the 2nd order ripple power, enabling the use of smaller DC-link capacitors, reducing the system volume and cost.
	[144]	Investigating a design methodology for inverter-side resistor-inductor (RL) filters aimed at mitigating motor overvoltage in (SiC)-based drives. The employed approach effectively addresses issues arising from impedance mismatches between inverters and motors.
	[145]	Developing a 10 kV (SiC) MOSFET power module. This configuration reduces parasitic inductances and capacitances, leading to a 53% increase in partial discharge inception voltage and a 90% reduction in common-mode current, enhancing high-voltage performance.
	[146]	Presenting a method to achieve zero switching loss in (SiC) MOSFETs by employing zero-voltage switching (ZVS), thereby minimizing thermal limitations, and enabling operation at higher switching frequencies.
	[147]	Designing a system-level tool that optimizes the power density of 3-phase, two-level SiC-based inverters. The developed design tool predicts a 159 % power density increase over Si-based inverters.
	[148]	Investigating the integration of (WBG) semiconductor devices, into renewable energy systems and smart grids. Some circuit design requirements to maximize the advantages of (WBG) have been addressed. Moreover, the merits such as the efficiency and power density enhancement have been discussed as well.
	[149]	Addressing crosstalk and voltage oscillations in (SiC) MOSFET half-bridge converters by proposing a gate driver that generates a negative turn-off voltage without a negative power supply. It presents a simple snubber circuit to suppress the parasitic ringing. The findings confirm the effectiveness of the presented solutions to enhance the converter performance.
	[150]	Designing a high-power converter based on (SiC) device, reducing conduction losses, and enhances efficiency, which is suitable for applications requiring compact and efficient power conversion solutions.
	[151]	Investigating a half-bridge gate driver circuit for (SiC) MOSFETs. The topology significantly reduces the total switching power losses by approximately 55% compared to conventional voltage source gate drivers, enhancing the converter efficiency.
	[152]	Introducing an inductor-less dv/dt filter for 100 kW to 1 MW voltage source converters using (SiC) devices. The design eliminates bulky filter inductors.
	[153]	Presenting a design methodology for dv/dt filters tailored to (SiC)-based inverters in high-frequency motor-drive systems. Thermal and electrical constraints have been addressed to mitigate insulation stress on motor stator windings caused by high slew rates in line voltages.
	[154]	Exploring the integration of (WBG) semiconductors, specifically into variable speed drive inverters. It introduces a soft-switching modulation scheme. The study also evaluates low-voltage (GaN) devices in multi-level inverter structures to enhance the overall efficiency.BREAK

Table 9. Research Contributions related to System Design of WBG-based Systems (Continued).

System DesignBREAKand performance improvement	Ref.	Core Contribution
	[155]	Introducing a high-efficiency, high- power density On Board Chargers (OBCs) based on (WBG) devices. The design achieves reduced size, and lower electromagnetic interference (EMI), making it suitable for next-generation EV charging systems.
	[156]	Presenting high-performance GaN power transistors characterized by higher breakdown voltage and current density. The design improves the thermal performance, and device scalability. It addresses the major limitations of GaN devices.
	[157]	Proposing a variable frequency control strategy and optimized filter design for SiC-based wind inverters. The approach maximizes energy extraction while minimizing switching losses. The method enhances the performance by dynamically adjusting the inverter's operating frequency.
	[158]	Developing a reduced power losses inverter system using lower harmonic loss technology and ultra-compact inverters using SiC modules. The system reduces harmonic distortion, minimizes power losses, and permits higher power density. The weight of the developed Sic-based inverter has been reduced by 55% of a conventional IGBT inverter.
	[159]	Designing a current-source inverter (CSI) integrated motor drive utilizing dual-gate four-quadrant (WBG) power switches. This design enables bidirectional power flow, reduced switching losses, and enhanced system efficiency. The approach offers a compact, high-performance solution for next-generation motor drive systems.

Table 9. Research Contributions related to System Design of WBG-based Systems (Continued).

System DesignBREAKand performance improvement	Ref.	Core Contribution
	[155]	Introducing a high-efficiency, high- power density On Board Chargers (OBCs) based on (WBG) devices. The design achieves reduced size, and lower electromagnetic interference (EMI), making it suitable for next-generation EV charging systems.
	[156]	Presenting high-performance GaN power transistors characterized by higher breakdown voltage and current density. The design improves the thermal performance, and device scalability. It addresses the major limitations of GaN devices.
	[157]	Proposing a variable frequency control strategy and optimized filter design for SiC-based wind inverters. The approach maximizes energy extraction while minimizing switching losses. The method enhances the performance by dynamically adjusting the inverter's operating frequency.
	[158]	Developing a reduced power losses inverter system using lower harmonic loss technology and ultra-compact inverters using SiC modules. The system reduces harmonic distortion, minimizes power losses, and permits higher power density. The weight of the developed Sic-based inverter has been reduced by 55% of a conventional IGBT inverter.
	[159]	Designing a current-source inverter (CSI) integrated motor drive utilizing dual-gate four-quadrant (WBG) power switches. This design enables bidirectional power flow, reduced switching losses, and enhanced system efficiency. The approach offers a compact, high-performance solution for next-generation motor drive systems.

Table 10. Research Contributions related to Cooling Systems of WBG-based Systems.

Thermal management and Cooling systems	Ref.	Core Contribution
	[160]	Developing a cost-effective, 3D-printed heatsink for rapid prototyping of (WBG) power converters. The design enables faster development cycles, reduced prototyping costs, and enhanced thermal management in industrial and automotive applications.
	[161]	Investigating a cooling system for automotive (SiC) power modules using a modular manifold with an embedded heat sink. This design improves thermal management, reduces system size, and enhances the cooling efficiency.
	[162]	Proposing a cooling system for (SiC) traction inverters in EVs using heat pipes. This design enhances thermal dissipation, reduces temperature fluctuations, and improves inverter reliability and power density.
	[163]	Investigating cooling techniques and enclosure designs for integrated motor drives (IMDs). It evaluates various cooling methods, including liquid and air-based systems, to optimize thermal management and enhance drive performance.
	[164]	Carrying out a thermal analysis of housing-cooled integrated motor drives (IMDs). The study examines the heat dissipation performance of housing-based cooling systems, highlighting design factors that improve thermal management. Their approach enables more compact, efficient, and reliable IMD designs.
	[165]	Developing a cooling design tool for EV (SiC) inverters using transient 3D-CFD simulations. The tool optimizes thermal performance by predicting heat dissipation and fluid flow dynamics. This approach enhances inverter cooling efficiency and reduces system size.
	[166]	Presenting a comprehensive review of cooling concepts and thermal management techniques for automotive (WBG) inverters. It categorizes cooling topologies, technologies, and integration strategies.
	[167]	Proposing a design methodology of air-cooled (SiC) inverters employed in EVs, optimizing thermal management, power density. The paper enables compact, efficient, and cost-effective SiC inverters.
	[168]	Presenting an optimal design of an integrated heat pipe air-cooled system for SiC MOSFET converters using the Teaching-Learning-Based Optimization algorithm. Their approach enhances thermal performance, minimizes cooling system size, and improves converter efficiency.

Table 10. Research Contributions related to Cooling Systems of WBG-based Systems.

Thermal management and Cooling systems	Ref.	Core Contribution
	[160]	Developing a cost-effective, 3D-printed heatsink for rapid prototyping of (WBG) power converters. The design enables faster development cycles, reduced prototyping costs, and enhanced thermal management in industrial and automotive applications.
	[161]	Investigating a cooling system for automotive (SiC) power modules using a modular manifold with an embedded heat sink. This design improves thermal management, reduces system size, and enhances the cooling efficiency.
	[162]	Proposing a cooling system for (SiC) traction inverters in EVs using heat pipes. This design enhances thermal dissipation, reduces temperature fluctuations, and improves inverter reliability and power density.
	[163]	Investigating cooling techniques and enclosure designs for integrated motor drives (IMDs). It evaluates various cooling methods, including liquid and air-based systems, to optimize thermal management and enhance drive performance.
	[164]	Carrying out a thermal analysis of housing-cooled integrated motor drives (IMDs). The study examines the heat dissipation performance of housing-based cooling systems, highlighting design factors that improve thermal management. Their approach enables more compact, efficient, and reliable IMD designs.
	[165]	Developing a cooling design tool for EV (SiC) inverters using transient 3D-CFD simulations. The tool optimizes thermal performance by predicting heat dissipation and fluid flow dynamics. This approach enhances inverter cooling efficiency and reduces system size.
	[166]	Presenting a comprehensive review of cooling concepts and thermal management techniques for automotive (WBG) inverters. It categorizes cooling topologies, technologies, and integration strategies.
	[167]	Proposing a design methodology of air-cooled (SiC) inverters employed in EVs, optimizing thermal management, power density. The paper enables compact, efficient, and cost-effective SiC inverters.
	[168]	Presenting an optimal design of an integrated heat pipe air-cooled system for SiC MOSFET converters using the Teaching-Learning-Based Optimization algorithm. Their approach enhances thermal performance, minimizes cooling system size, and improves converter efficiency.

Table 10. Research Contributions related to Cooling Systems of WBG-based Systems (Continued).

Thermal management and Cooling systems	Ref.	Core Contribution
	[169]	Presenting an automated methodology for designing and optimizing air-cooled heatsinks for SiC power modules. It integrates genetic algorithms with finite element analysis. Complex heatsink geometries have been generated with this approach. The findings indicate that the size of the optimized heatsink is less than the conventional design approach by 27 %, meanwhile the resultant junction temperature is reduced by 6 %.
	[170]	Introducing a thermal management design methodology for SiC power devices and systems using genetic optimization algorithms to achieve optimum geometries for liquid-cooled heat sink. This approach enables the creation of effective complex cooling structures for power electronic systems.
	[171]	Proposing a design optimization method for liquid-cooled heat sinks in (WBG) power modules, utilizing Fourier analysis and evolutionary multi-objective optimization. The developed heat sinks with this approach outperforms the conventional heat sinks shapes.
	[172]	presenting a double-sided cooling method for discrete SiC MOSFETs using a press-pack package. This approach enhances thermal dissipation, enabling higher power density and reducing thermal stress. The design achieves improved heat distribution and increased device reliability.
	[173]	Investigating the performance of (SiC) and (GaN) devices under cryogenic cooling. The findings indicate that SiC-MOSFETs have relatively greater on-state resistance and relatively slower switching speeds at low temperatures, while GaN devices demonstrate improved performance.
	[174]	Investigating a design of a power electronics package that integrates different materials. The design improves thermal cycling reliability of liquid-cooled Aluminum SiC heat sinks. The proposed structure and layers minimizes the coefficient of thermal expansion mismatch in the stack by 84 %, extending the lifetime of the package and permits reduction in the volume and weight.
	[175]	Presenting thermal analysis and material selection methodology for (SiC)-based Intelligent Power Modules (IPMs). By evaluating various materials and their thermal properties, the study aims to enhance the thermal performance and reliability of SiC IPMs.
	[176]	Designing a thermally uniform heatsink for high-power SiC inverters employed in EVs. A novel heatsink geometry that improves cooling efficiency and thermal uniformity is presented.
	[177]	Investigating a thermal modeling and simulation method for optimizing power density in SiC-MOSFET inverters. The proposed approach allows for optimal placement and design of power modules, optimizing the volume and compactness of the SiC-MOSFET inverter.
	[178]	Proposing an optimal thermal design for SiC power modules. A double-sided cooling strategy to enhance heat dissipation and thermal uniformity is presented. Compact, and reliable SiC-based power modules for high-voltage applications can be achieved.
	[179]	Introducing a liquid cooling method for SiC power modules. The proposed method is based on direct liquid contact with the surface of the power module, enhancing thermal dissipation, and reducing thermal resistance.
	[180]	Presenting a passive cooling system for high-power SiC power electronic converters. The proposed heat sink enhances heat dissipation and thermal uniformity using phase-change heat transfer. The presented cooling system results in a reduced thermal resistance, improving the cooling efficiency.
	[181]	Proposing cooling strategies and thermal management methods for (WBG)-based current-source inverter (CSI) employed in motor drives. With the proposed approach, the system compactness is enhanced.
	[182]	Investigating a thermal design methodology for WBG-inverters. An optimized cooling structure is proposed. The developed design improves heat dissipation and increases the reliability of WBG-inverters.

Table 10. Research Contributions related to Cooling Systems of WBG-based Systems (Continued).

Thermal management and Cooling systems	Ref.	Core Contribution
	[169]	Presenting an automated methodology for designing and optimizing air-cooled heatsinks for SiC power modules. It integrates genetic algorithms with finite element analysis. Complex heatsink geometries have been generated with this approach. The findings indicate that the size of the optimized heatsink is less than the conventional design approach by 27 %, meanwhile the resultant junction temperature is reduced by 6 %.
	[170]	Introducing a thermal management design methodology for SiC power devices and systems using genetic optimization algorithms to achieve optimum geometries for liquid-cooled heat sink. This approach enables the creation of effective complex cooling structures for power electronic systems.
	[171]	Proposing a design optimization method for liquid-cooled heat sinks in (WBG) power modules, utilizing Fourier analysis and evolutionary multi-objective optimization. The developed heat sinks with this approach outperforms the conventional heat sinks shapes.
	[172]	presenting a double-sided cooling method for discrete SiC MOSFETs using a press-pack package. This approach enhances thermal dissipation, enabling higher power density and reducing thermal stress. The design achieves improved heat distribution and increased device reliability.
	[173]	Investigating the performance of (SiC) and (GaN) devices under cryogenic cooling. The findings indicate that SiC-MOSFETs have relatively greater on-state resistance and relatively slower switching speeds at low temperatures, while GaN devices demonstrate improved performance.
	[174]	Investigating a design of a power electronics package that integrates different materials. The design improves thermal cycling reliability of liquid-cooled Aluminum SiC heat sinks. The proposed structure and layers minimizes the coefficient of thermal expansion mismatch in the stack by 84 %, extending the lifetime of the package and permits reduction in the volume and weight.
	[175]	Presenting thermal analysis and material selection methodology for (SiC)-based Intelligent Power Modules (IPMs). By evaluating various materials and their thermal properties, the study aims to enhance the thermal performance and reliability of SiC IPMs.
	[176]	Designing a thermally uniform heatsink for high-power SiC inverters employed in EVs. A novel heatsink geometry that improves cooling efficiency and thermal uniformity is presented.
	[177]	Investigating a thermal modeling and simulation method for optimizing power density in SiC-MOSFET inverters. The proposed approach allows for optimal placement and design of power modules, optimizing the volume and compactness of the SiC-MOSFET inverter.
	[178]	Proposing an optimal thermal design for SiC power modules. A double-sided cooling strategy to enhance heat dissipation and thermal uniformity is presented. Compact, and reliable SiC-based power modules for high-voltage applications can be achieved.
	[179]	Introducing a liquid cooling method for SiC power modules. The proposed method is based on direct liquid contact with the surface of the power module, enhancing thermal dissipation, and reducing thermal resistance.
	[180]	Presenting a passive cooling system for high-power SiC power electronic converters. The proposed heat sink enhances heat dissipation and thermal uniformity using phase-change heat transfer. The presented cooling system results in a reduced thermal resistance, improving the cooling efficiency.
	[181]	Proposing cooling strategies and thermal management methods for (WBG)-based current-source inverter (CSI) employed in motor drives. With the proposed approach, the system compactness is enhanced.
	[182]	Investigating a thermal design methodology for WBG-inverters. An optimized cooling structure is proposed. The developed design improves heat dissipation and increases the reliability of WBG-inverters.

Table 11. Research Contributions related to Key Challenges and Solutions of WBG-based Systems.

Key challenges and solutions	Ref.	Core Contribution
	[183]	Presenting a review including key challenges and solutions for GaN power semiconductor modules. Advancements in GaN technology has been addressed. The paper discusses the main challenges such as parasitic effects, and thermal stress. Some proposed solutions have been addressed as well.
	[184,185]	Providing a review on the key advancements, challenges and future trends in WBG semiconductor technologies for modern automotive and renewable energy systems. Innovations in device design, and fabrication technologies have been addressed.
	[186]	Highlighting the superior performance of (WBG) devices in power electronic converters. It presents some design methodologies and addresses key challenges like parasitic effects and thermal stress.
	[187]	Addressing advancements in (WBG) devices, for the automotive industry. Items such as power density, efficiency, and thermal performance, have been discussed. Moreover, main challenges, including cost, reliability, and integration, are also presented.
	[188]	Discussing the main challenges that affect the reliability and performance of SiC and GaN power semiconductor devices. The article suggests a roadmap for enhancing the quality and reliability of WBG devices for next generation power electronic converters.
	[189]	Reviewing the reliability challenges and packaging of (WBG) devices .The article provides information about improving the devices lifespan and durability for various applications.
	[190]	Investigating the potential of (WBG) in power electronics. It highlights their superior efficiency, higher switching frequencies, and elevated temperature operation compared to silicon-based devices. Main challenges have been addressed as well.
	[191]	Providing a review of packaging technologies and challenges of (SiC) power modules. like high-speed switching, thermal management, high-temperature operation, and high-voltage isolation. It discusses emerging issues in soft-switching converters and low-temperature applications of SiC devices.
	[192]	Addressing switching oscillations in (WBG) semiconductor devices. It classifies oscillation types, analyzes their causes and effects. Suppression techniques have been presented to enhance the performance and reliability of WBG-based power electronic converters.
	[193]	Investigating the integration of (CMOS) logic with (WBG) and (Ultra-WBG) semiconductors. The articles identifies challenges such as material defects and fabrication complexities. It also presents directions and guidelines to overcome these challenges.
	[194]	Discussing the potential of (WBG) power semiconductor devices. It presents the International Technology Roadmap for WBG devices, highlighting the challenges and strategies for accelerating adoption and commercial acceptance of WBG-based devices and converters.
	[195]	Addressing advancements in (WBG) semiconductors. The paper outlines the programs of U.S. Department of Energy that have fostered the innovations through the value chain of power electronics.
	[196]	Presenting the major application of (SiC) power devices. The article addresses the main obstacles such as the crosstalk effects, current overshoot and electromagnetic interference. It also presents the possible solutions to alleviate the adverse effects of such obstacles.
	[197]	Provide a review of employment of wide-bandgap (WBG) power semiconductor modules in EVs. Main design aspects such as die parallelization and Direct Bonded Copper (DBC) routing, have been discussed to enhance efficiency and performance of EV drives.
	[198]	Designing of 30-kVA three-phase (SiC) MOSFETs inverter that can operate at ambient temperatures up to 180 °C. Key challenges of operation at such high-temperature have been addressed. The findings prove that SiC-based inverters are feasible in harsh environments.
	[199]	Investigating the obstacles that prevent the widespread and adoption of (WBG) semiconductors in power electronics applications. The main challenges like material defects and high manufacturing costs have been discussed Some solutions have been addressed to overcome such challenges.
	[200]	Discussing the application and advantages of (SiC) power devices. The paper discusses challenges and suggest solutions to enhance the performance of SiC devices.
	[201]	Providing a comprehensive review of methods for suppressing conductive common-mode electromagnetic interference in inverter-fed motor drives. The paper also discusses the impact of emerging WBG devices on EMI.
	[202]	Designing an inverter for EV based on double-sided cooled (SiC) power modules. This method enhances thermal management and increases the power densities, thereby, contributing higher reliability and compactness of the inverter.
	[203]	Addressing the characteristics and commercial status of (GaN) power devices, highlighting their potential for higher frequency and efficiency in power electronic converters compared to conventional Si devices. It also discusses some challenges such as gate driver design, unique reverse conduction behavior, and breakdown mechanisms of the device.

Table 11. Research Contributions related to Key Challenges and Solutions of WBG-based Systems.

Key challenges and solutions	Ref.	Core Contribution
	[183]	Presenting a review including key challenges and solutions for GaN power semiconductor modules. Advancements in GaN technology has been addressed. The paper discusses the main challenges such as parasitic effects, and thermal stress. Some proposed solutions have been addressed as well.
	[184,185]	Providing a review on the key advancements, challenges and future trends in WBG semiconductor technologies for modern automotive and renewable energy systems. Innovations in device design, and fabrication technologies have been addressed.
	[186]	Highlighting the superior performance of (WBG) devices in power electronic converters. It presents some design methodologies and addresses key challenges like parasitic effects and thermal stress.
	[187]	Addressing advancements in (WBG) devices, for the automotive industry. Items such as power density, efficiency, and thermal performance, have been discussed. Moreover, main challenges, including cost, reliability, and integration, are also presented.
	[188]	Discussing the main challenges that affect the reliability and performance of SiC and GaN power semiconductor devices. The article suggests a roadmap for enhancing the quality and reliability of WBG devices for next generation power electronic converters.
	[189]	Reviewing the reliability challenges and packaging of (WBG) devices .The article provides information about improving the devices lifespan and durability for various applications.
	[190]	Investigating the potential of (WBG) in power electronics. It highlights their superior efficiency, higher switching frequencies, and elevated temperature operation compared to silicon-based devices. Main challenges have been addressed as well.
	[191]	Providing a review of packaging technologies and challenges of (SiC) power modules. like high-speed switching, thermal management, high-temperature operation, and high-voltage isolation. It discusses emerging issues in soft-switching converters and low-temperature applications of SiC devices.
	[192]	Addressing switching oscillations in (WBG) semiconductor devices. It classifies oscillation types, analyzes their causes and effects. Suppression techniques have been presented to enhance the performance and reliability of WBG-based power electronic converters.
	[193]	Investigating the integration of (CMOS) logic with (WBG) and (Ultra-WBG) semiconductors. The articles identifies challenges such as material defects and fabrication complexities. It also presents directions and guidelines to overcome these challenges.
	[194]	Discussing the potential of (WBG) power semiconductor devices. It presents the International Technology Roadmap for WBG devices, highlighting the challenges and strategies for accelerating adoption and commercial acceptance of WBG-based devices and converters.
	[195]	Addressing advancements in (WBG) semiconductors. The paper outlines the programs of U.S. Department of Energy that have fostered the innovations through the value chain of power electronics.
	[196]	Presenting the major application of (SiC) power devices. The article addresses the main obstacles such as the crosstalk effects, current overshoot and electromagnetic interference. It also presents the possible solutions to alleviate the adverse effects of such obstacles.
	[197]	Provide a review of employment of wide-bandgap (WBG) power semiconductor modules in EVs. Main design aspects such as die parallelization and Direct Bonded Copper (DBC) routing, have been discussed to enhance efficiency and performance of EV drives.
	[198]	Designing of 30-kVA three-phase (SiC) MOSFETs inverter that can operate at ambient temperatures up to 180 °C. Key challenges of operation at such high-temperature have been addressed. The findings prove that SiC-based inverters are feasible in harsh environments.
	[199]	Investigating the obstacles that prevent the widespread and adoption of (WBG) semiconductors in power electronics applications. The main challenges like material defects and high manufacturing costs have been discussed Some solutions have been addressed to overcome such challenges.
	[200]	Discussing the application and advantages of (SiC) power devices. The paper discusses challenges and suggest solutions to enhance the performance of SiC devices.
	[201]	Providing a comprehensive review of methods for suppressing conductive common-mode electromagnetic interference in inverter-fed motor drives. The paper also discusses the impact of emerging WBG devices on EMI.
	[202]	Designing an inverter for EV based on double-sided cooled (SiC) power modules. This method enhances thermal management and increases the power densities, thereby, contributing higher reliability and compactness of the inverter.
	[203]	Addressing the characteristics and commercial status of (GaN) power devices, highlighting their potential for higher frequency and efficiency in power electronic converters compared to conventional Si devices. It also discusses some challenges such as gate driver design, unique reverse conduction behavior, and breakdown mechanisms of the device.

Owing to Ref. [204], typical state-of-the-art ratings and main manufacturers of SiC power transistors, as one of the WBG power semiconductor devices, are summarized in Table 12.

Table 12. Typical Ratings and Some Manufacturers of SiC Power MOSFET.

Manufacturer	Voltage Rating [V]	Current Rating [A]
ST Microelectronis	600-2200	7-300
Infineon	400-2000	5.2-238
Semikrone	1200-1700	18-485
Microchip	700-3300	6-149
IXYS	900-1700	3.5-142
Mitsubishi	1200-1700	100-1200
Toshiba	650-1200	20-100
Alfa & Omega	650-1200	6.3-96
Solitron	650-1200	40-120
WeEn	650-1700	4.6-216

Reference[204]: https://us.metoree.com/categories/sic-mosfet/.

Table 12. Typical Ratings and Some Manufacturers of SiC Power MOSFET.

Manufacturer	Voltage Rating [V]	Current Rating [A]
ST Microelectronis	600-2200	7-300
Infineon	400-2000	5.2-238
Semikrone	1200-1700	18-485
Microchip	700-3300	6-149
IXYS	900-1700	3.5-142
Mitsubishi	1200-1700	100-1200
Toshiba	650-1200	20-100
Alfa & Omega	650-1200	6.3-96
Solitron	650-1200	40-120
WeEn	650-1700	4.6-216

Reference[204]: https://us.metoree.com/categories/sic-mosfet/.

4. Main Control Techniques of IM Drives

4.1. Introduction

The commonly used control techniques applied in industrial IM drives are the Field Oriented Control (FOC) and Direct Torque Control (DTC). The FOC originated by Blaschke in[205] is utilized in IM drives when a precise speed and a high dynamic response are required [206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223].

Few decades after inventing the FOC, the Direct Torque Control (DTC) technique is proposed by the authors of [12] to provide fast dynamic response and well control of both motor flux and electromagnetic torque [224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239]. The first industrial DTC-based IM drive was designed and fabricated by ABB in 1996, introduced in [240].

On the other hand, many research activities have been conducted recently aiming to employ the Finite Control Set-Model Predictive Control (FCS-MPC) approach to regulate both motor speed, torque and flux based on the dynamic model of the IM.

Moreover, for high efficiency IM drives, the core control algorithms can involve efficiency optimization task/subroutine (function) to minimize the energy consumption by operating at optimum levels of flux and minimizing the reactive component of the current drawn from the AC supply. Also, adopting regenerative braking approach enhances the overall efficiency of the AC drive by returning to the grid the mechanical energy stored in the motor shaft during the braking instants.

4.2. Field Oriented Control

The commonly used and well-known scalar control methods of IMs provide satisfactory steady performance for economic general purpose AC drives. However, they are neither able to provide high transient response, nor they are suitable for precise operation and applications at low and very low speeds. Beside to that, scalar methods fail to achieve position control of IMs as servo drives. Field oriented control or vector control (VC) technique for IM drives has been originated to overcome the main limitations of the scalar control methods

The FOC or VC technique aims to emulate the decoupled control features of conventional separately excited DC motor, by decomposing the stator current vector into two orthogonal components: direct component I_d and quadrature component I_q. The direct component I_d is responsible for air gap flux production, while the quadrature component I_q is responsible for electromagnetic torque production, as illustrated in Figure 7. This way, the FOC emulates the behavior of the DC motor which results in high dynamic performance and good transient response under sudden load variations, provided that the machine parameters are on-line identified during the motor operation.

The block diagram of the basic scheme of FOC of IM drives is presented in Figure 8.

In VC or FOC system of 3-F IM, the reference electromagnetic torque ${\mathrm{T}}_{\mathrm{e}\mathrm{m}\mathrm{r}\mathrm{e}\mathrm{f}}^{*}$ is computed as the output of the PI-speed controller. The reference stator flux ${\mathrm{F}}_{\mathrm{S}\mathrm{r}\mathrm{e}\mathrm{f}}^{*}$ is a function of the reference speed, involving the operation in the field weakening mode for motor operation at speeds above the rated value, as illustrated in the lower part of Figure 8. Meanwhile, the reference stator currents ${\mathrm{i}}_{\mathrm{S}\mathrm{d}\mathrm{r}\mathrm{e}\mathrm{f}}^{*}$ and ${\mathrm{i}}_{\mathrm{S}\mathrm{q}\mathrm{r}\mathrm{e}\mathrm{f}}^{*}$ in the d-q coordinates are generated with the aid of IM parameters and its model equations given below:

$${\mathrm{i}}_{\mathrm{S}\mathrm{d}\mathrm{r}\mathrm{e}\mathrm{f}}^{\mathrm{*}}={\displaystyle \frac{{\mathsf{\Phi }}_{\mathrm{S}\mathrm{r}\mathrm{e}\mathrm{f}}^{\mathrm{*}}}{{\mathrm{L}}_{\mathrm{S}}}}$$

(1)

$${\mathrm{i}}_{\mathrm{S}\mathrm{q}\mathrm{r}\mathrm{e}\mathrm{f}}^{\mathrm{*}}={\displaystyle \frac{4}{3}}{\displaystyle \frac{{\mathrm{T}}_{\mathrm{e}\mathrm{m}\mathrm{r}\mathrm{e}\mathrm{f}}^{\mathrm{*}}}{{\mathrm{P}\mathsf{\Phi }}_{\mathrm{S}\mathrm{r}\mathrm{e}\mathrm{f}}^{\mathrm{*}}}}$$

(2)

The previous equations are based on the following assumptions:

1-

The stator flux linkage is typically aligned along the d-axis, and the q-axis flux component is zero. Accordingly: ${\mathsf{\Phi }}_{\mathrm{S}\mathrm{d}}^{\mathrm{*}}={\mathsf{\Phi }}_{\mathrm{S}\mathrm{r}\mathrm{e}\mathrm{f}}^{\mathrm{*}}$; ${\mathsf{\Phi }}_{\mathrm{S}\mathrm{q}}^{\mathrm{*}}=0$

2-

The reference stator current in the d-axis is directly related to the stator flux linkage.

3-

Rotor is short circuited, where:${\mathrm{V}}_{\mathrm{r}\mathrm{d}}={\mathrm{V}}_{\mathrm{r}\mathrm{d}}=0$

The electromagnetic torque is computed using the following equation:

$${\mathrm{T}}_{\mathrm{e}\mathrm{m}}={\displaystyle \frac{3}{2}}{\displaystyle \frac{\mathrm{P}}{2}}\left({\mathsf{\Phi }}_{\mathrm{S}\mathrm{d}}{\mathrm{i}}_{\mathrm{S}\mathrm{q}}-{\mathsf{\Phi }}_{\mathrm{S}\mathrm{q}}{\mathrm{i}}_{\mathrm{S}\mathrm{d}}\right)$$

(3)

The slip speed is determined using the following relation:

$${\mathsf{\omega }}_{\mathrm{s}\mathrm{l}\mathrm{i}\mathrm{p}}={\displaystyle \frac{{\mathrm{R}}_{\mathrm{r}}}{{\mathrm{L}}_{\mathrm{r}}}}{\displaystyle \frac{{\mathrm{i}}_{\mathrm{S}\mathrm{q}}}{{\mathrm{i}}_{\mathrm{S}\mathrm{d}}}}$$

(4)

$${\mathsf{\omega }}_{\mathrm{s}}={\mathsf{\omega }}_{\mathrm{s}\mathrm{l}\mathrm{i}\mathrm{p}}+{\mathsf{\omega }}_{\mathrm{m}}$$

(5)

Where:

${\mathrm{T}}_{\mathrm{e}\mathrm{m}}^{\mathrm{*}}$ is the reference electromagnetic torque (Nm); T_em is the instantaneous electromagnetic torque (Nm); ${\Phi }_{\mathrm{S}\mathrm{d}}$, ${\Phi }_{\mathrm{S}\mathrm{q}}$are the stator flux components in d-q synchronous reference frame (Wb); i_Sd , i_Sq are stator current components of stator current in d-q synchronous frame (A); ${\mathsf{\omega }}_{\mathrm{s}}$ is the synchronous speed (rad/s); ${\mathsf{\omega }}_{\mathrm{s}\mathrm{l}\mathrm{i}\mathrm{p}}$ is the slip speed (rad/s); ${\mathsf{\omega }}_{\mathrm{m}}$ is the motor mechanical speed (rad/s); P is the number of poles; L_s is the stator self-inductance (H); L_r is the rotor self-inductance (H); R_r is the rotor resistance (W); L_r is the rotor self-inductance (H);

Although the FOC provides good transient performance of the IM, it suffers from several drawbacks. Firstly, the successful operation depends on the accuracy of estimation (computation) of slip speed (${\mathsf{\omega }}_{\mathrm{s}\mathrm{l}\mathrm{i}\mathrm{p}}$) and the angle (q), which depend on the rotor time constant (L_r/R_r) that varies with the temperature and level of saturation.

In fact, considerable research efforts have been done in VC and FOC of IM during the period (1992-2008), with the advancement in DPS and Microcontroller technologies. However, The main observed research contributions of FOC of IM drives during the period (2017 to 2024) are summarized and presented in Table 13.

4.3. Direct Torque Control

DTC strategy of IM drives controls directly both stator flux and electromagnetic torque by applying instantaneously the optimum inverter switching state which satisfy both torque and flux requirements. The DTC scheme of 3-F IM is composed of the following blocks:

1- Motor transient model to calculate the instantaneous value of the stator flux vector and electromagnetic torque.

2- Two hysteresis ON/OFF controllers: one for the stator flux and the other is for the torque.

3- Optimum switching table whose output is the instantaneous values of the inverter switching state that such that the flux and torque track the set points (reference values).

The DTC strategy of IM drive can have two modes of operation: torque control mode and speed control mode. In torque control mode, the desired electromagnetic torque is the reference signal. In speed control mode, the reference torque is the output of speed controller. The reference flux signal is a function of the motor reference speed. For speeds greater than the rated value, the reference stator flux is reduced, running the motor in field weakening mode.

The flux and torque control under DTC can be explained with the aid of Figure 10 and 11 respectively, where the stator flux vector initially lies in sector number one. Each discrete inverter switching state and the corresponding voltage vector has its effect on both electromagnetic torque and stator Flux. E.g., if the voltage vector V₁ is applied during the sampling period, the magnitude of the stator flux will increase. At the same time, the angle between stator and rotor flux vectors will decrease, which results in a reduction in the instantaneous value of the electromagnetic torque. (From the principles of electric machines, the magnitude of the electromagnetic torque is directly proportional to the SINE value of the angle between stator and rotor flux vectors).

Figure 9. Block Diagram Of Conventional DTC System of IM Drive.

Figure 9. Block Diagram Of Conventional DTC System of IM Drive.

Figure 11. Control Of Motor Stator Flux And Torque In Sector 1.

Figure 11. Control Of Motor Stator Flux And Torque In Sector 1.

While applying vector V₄ instead of V₁ results in a reduction in magnitude of stator flux as illustrated in Figure 10. At the same time, the angle between stator and rotor flux vectors will increase, which results in an increment in the instantaneous value of the electromagnetic torque. From these observations, an optimum switching table is obtained to control simultaneously both stator flux and electromagnetic torque.

Figure 12 summarizes the effects of all inverter voltage vectors on both torque and flux in Sector 1.

The ideal trajectory of the stator flux vector is a circular path. Under DTC strategy, the actual path is formed by applying instantaneously the optimum inverter voltage vectors. Such optimum vectors depend on both the current location of the stator flux vector (Sector number 1:6) and the direction of rotation as well.

Figure 13 clarifies and indicates the selection method of the inverter optimum vectors in Sectors ONE and TWO, where:

For CCW rotation in Sector ONE, vectors V₂ and V₃ are to be mutually applied to follow the desired flux trajectory. While in Sector TWO, vectors V₃ and V₄ are to be mutually applied to follow up the required stator flux trajectory.

For CW rotation in Sector ONE, vectors V₅ and V₆ are to be mutually applied to keep track of the desired flux locus. While in Sector TWO, vectors V₁ and V₆ are to be mutually applied in sector 2. Again,

The stator flux components int (a-b) stationary reference frame are computed using the following equations:

$${\overline{\Phi }}_{\mathrm{S}}={\Phi }_{\mathsf{\alpha }}+\mathrm{j}{\Phi }_{\mathsf{\beta }}$$

(6)

$${\Phi }_{\alpha }={\int }_0^{{\mathrm{T}}_{\mathrm{S}}}\left(v_{\alpha }-{\mathrm{R}}_{\mathrm{S}}{i}_{\alpha }\right)\mathrm{d}\mathrm{t}$$

(7)

$${\Phi }_{\beta }={\int }_0^{{\mathrm{T}}_{\mathrm{S}}}\left(v_{\beta }-{\mathrm{R}}_{\mathrm{S}}{i}_{\beta }\right)\mathrm{d}\mathrm{t}$$

(8)

Where T_S is the sampling period of the DTC algorithm in digital implementation.

The magnitude and the location of the stator flux vector are computed by Eqns. (9) and (10) respectively. They are inputs to the DTC blocks (hysteresis flux controller and the inverter switching table) as shown in Figure 9.

$$\left|{\Phi }_{\mathrm{S}}\right|=\sqrt{{\Phi }_{\alpha }^2+{\Phi }_{\beta }^2}$$

(9)

$${\Phi }_{\mathrm{S}}={\mathrm{t}\mathrm{a}\mathrm{n}}^{-1}\left({\displaystyle \frac{{\Phi }_{\beta }}{{\Phi }_{\alpha }}}\right)$$

(10)

The electromagnetic torque produced by the IM is calculated using Equations (11) and (12):

$${\mathrm{T}}_{\mathrm{e}\mathrm{m}}={\displaystyle \frac{3}{2}}{\displaystyle \frac{\mathrm{P}}{2}}\left({\overline{\Phi }}_{\mathrm{S}}\mathrm{x}{\overline{\mathrm{I}}}_{\mathrm{S}}\right)$$

(11)

$${\mathrm{T}}_{\mathrm{e}\mathrm{m}}={\displaystyle \frac{3}{2}}{\displaystyle \frac{\mathrm{P}}{2}}\left({\Phi }_{\alpha }{i}_{\beta }-{\Phi }_{\beta }{i}_{\alpha }\right)$$

(12)

Where P is the number of magnetic poles of the AC motor.

The stator current components in (a-b) stationary reference frame are determined using Equations (14) and (15):

$${\overline{\mathrm{I}}}_{\mathrm{S}}=i_{\mathsf{\alpha }}+\mathrm{j}{i}_{\mathsf{\beta }}$$

(13)

$$i_{\mathsf{\alpha }}={\displaystyle \frac{1}{3}}\left({2i}_{\mathrm{a}}-i_{\mathrm{b}}-i_{\mathrm{c}}\right)$$

(14)

$$i_{\mathsf{\beta }}={\displaystyle \frac{1}{\sqrt{3}}}\left(i_{\mathrm{b}}-i_{\mathrm{c}}\right)$$

(15)

The major advantages of DTC are the quick response of both torque and flux. Also, dependency of DTC algorithm to on a machine model with a moderate degree of complexity, not like FOC which is based on sophisticated machine mode.

However, the main drawbacks of the DTC are the requirement of online identification of stator resistance to achieve high performance at low speeds, meanwhile the conventional scheme is not applicable for position control and servo applications.

In fact, considerable research activities in DTC drives have been carried out during the period (1997-2017). The main observed research contributions of DTC for IM drives during the period (2017 to 2024) are summarized and presented in Table 14.

4.5. Model Predictive Control

Recently, Finite Control Set Model Predictive Control (FCS-MPC) is applied in IM drives as an advanced control approach [241,242,243,244,245,246,247,248,249,250,251,252,253,254,255,256,257] to minimize the torque and flux ripples and achieving other goals such as minimization of switching frequency [271].

In the FCS-MPC technique, the future behavior of the controlled variables (stator flux and electromagnetic torque in case of IM drives) are predicted for a finite time frame of one or more sampling period. Accordingly, the optimum future control action is applied to the motor to satisfy a customized goal function, where the FCS-MPC algorithm repeatedly checks the future behavior at every sampling period. Therefore, in addition to the main speed control (regulation) task, other goals can be achieved such as minimization of flux and torque ripples, minimization inverter switching frequency, minimization of stator current ripple, or minimization of active and reactive power ripples. Accordingly, the cost function can accommodate all these terms and more upon owing to the performance requirement of the IM drive as demonstrated in Equations 16, 17, 18, and 19:

$$J_1=\left|{\mathrm{T}}_{\mathrm{e}\mathrm{m}}^{\mathrm{*}}-{\mathrm{T}}_{\mathrm{e}\mathrm{m}}^{\mathrm{k}+1}\right|+\left|{\Phi }_{\mathrm{S}}^{\mathrm{*}}-{\Phi }_{\mathrm{S}}^{\mathrm{k}+1}\right|$$

(16)

$$J_2=\left|{\mathrm{T}}_{\mathrm{e}\mathrm{m}}^{\mathrm{*}}-{\mathrm{T}}_{\mathrm{e}\mathrm{m}}^{\mathrm{k}+1}\right|+\left|{\Phi }_{\mathrm{S}}^{\mathrm{*}}-{\Phi }_{\mathrm{S}}^{\mathrm{k}+1}\right|+{\mathrm{F}}_{\mathrm{SWT}}$$

(17)

$$J_3=\left|{\mathrm{i}}_{\mathrm{S}}^{\mathrm{*}}-{\mathrm{i}}_{\mathrm{S}}^{\mathrm{k}+1}\right|+\left|{\mathrm{i}}_{\mathrm{S}}^{\mathrm{*}}-{\mathrm{i}}_{\mathrm{S}}^{\mathrm{k}+1}\right|$$

(18)

$$J_{pq1}=\left|{\mathrm{P}}_{\mathrm{r}\mathrm{e}\mathrm{f}}-{\mathrm{P}}^{\mathrm{k}+1}\right|+\left|{\mathrm{Q}}_{\mathrm{r}\mathrm{e}\mathrm{f}}-{\mathrm{Q}}^{\mathrm{k}+1}\right|$$

(19)

The absolute value functions of the previous equations can be replaced by square function for minimizing the terms of the formulated cost functions, Moreover, each term can have a weight factor (w_p and w_q) to prioritize some term(s) during operation as given by Eqn. 20:

$$J_{pq2}={{\mathrm{w}}_{\mathrm{p}}\left({\mathrm{P}}_{\mathrm{r}\mathrm{e}\mathrm{f}}-{\mathrm{P}}^{\mathrm{k}+1}\right)}^2+{{\mathrm{w}}_{\mathrm{q}}\left({\mathrm{Q}}_{\mathrm{r}\mathrm{e}\mathrm{f}}-{\mathrm{Q}}^{\mathrm{k}+1}\right)}^2$$

(20)

The block diagram of FCS-MPC of IM drives is shown in Figure 14. The control system has three main parts:

1- Speed control loop and reference signals generation of torque and flux. The output of the PI speed controller represents the desired electromagnetic torque, while the reference stator flux is kept constant at the rated value for the entire range of speed from zero to the rated value. Above the rated, the flux is reduced inversely to verify field weakening mode.

2- Computation of stator currents and stator voltages components in the (a-b) stationary reference frame.

3- FCS-MPC algorithm, which is composed of several blocks and functions, such as prediction of stator currents and stator flux components in the stationary reference frame (a-b) one sample ahead, and prediction of electromagnetic torque one sample ahead as well. Finally, In FCS-MPC, the customized cost function is calculated and checked for all possible inverter switching states. Then, the optimum inverter switching state that instantaneously provide minimum cost function is chosen and applied to the IM.

The FCS-MPC approach requires a high speed DSP unit to implement the several functions and subroutines related to the sophisticated algorithm. The accuracy of stator flux and electromagnetic torque prediction depends on the machine parameters plugged into the model. Thus, any deviation from the real values, which are affected by temperature and saturation level of the machine, affect negatively the performance of the IM drive, and maybe the stability as well.

Recently, several research efforts have been exerted in applying and investigating the IM drive under FCS-MPC approach. The summary of main research contributions during the period (2017 to 2024) is presented in Table 15.

4.6. Regenerative Braking and Energy Saving

Applying Regenerative Braking is one of the important strategies that are employed in industrial AC drives and EV, because it is an effective and efficient energy recovery technique that minimize the overall consumption, beside to that it provides quick stopping of the electric machine [258,259,260,261,262,263,264,265,266,267,268,269,270].

In case of EV, this energy is utilized to charge the battery, increasing the distance range of the EV. In medium and high power range, AC drives apply regenerative braking technique to return the shaft kinetic energy to the electric grid during braking instants as in electric trains [14,15].

Research Contributions in Regenerative Braking & Energy Saving of IM Drives during the period 2017 to 2024 are presented and summarized in Table 16

5. Manufacturers of Industrial IM Drives

A summary of the well-known industrial AC drives manufacturers (ordered alphabetically) and the employed control techniques in their products are summarized in Table 17. Most manufacturers produce scalar V/F drives and vector control VC drives (with position/speed encoder or sensorless drive), while few players adopt DTC technology.

The major observation is that the MPC has not gain yet the industrial acceptance. However, PowerFlex® 750 AC drives series, with totalFORCE® technology from Allen-Bradely provides adaptive control of position, velocity, and torque for AC motors [290,291].

6. Conclusions

This article aims to provide a guide and a summary to the recent trends in high efficiency induction motor drives during the period (2017-2024). The selected period is narrowed to only the last seven years to involve the state-of-the art carried out research activities. However, considerable respectful research publications covering the same topics have been published during the previous two decades. However, the pioneer contributions during the last three decades can not be ignored and have been addressed through the corresponding covered topic in the article.

The study conclusions and findings are summarized in the following points:

1- Development and adopting high efficiency AC drives, especially IM drives, is an important issue in the modern industry to reduce energy consumption in different sectors in accordance with energy efficiency standards and restrictions.

1-

Design and implementation of high efficiency and premium efficiency IMs have commercial acceptance as many manufacturers fabricate considerable products covering a wide power range serving multiple applications.

2-

Design of high efficiency IMs using evolutionary optimization techniques and modern analysis tools such as finite element have great interest from academia and industry.

3-

Many recent research papers are interested in studying and investigating thermal equivalent circuits of IMs to optimize and enhance motor cooling system to raise the efficiency.

4-

WBG power semiconductor devices are gradually taking place in the development of commercial IM drives due to salient advantages. E.g., SiC devices are suitable for high power applications, meanwhile GaN is convenient to low voltage/low power application very high frequency applications.

5-

Some fabrication challenges of WBG power devices are still existing. However, considerable research efforts tackle these obstacle and find solutions to most of them. So, the prices of WBG devices are decreasing with the time to get the commercial acceptance.

6-

The industrial IM drives are still depending on scalar control techniques for general purpose application. Meanwhile vector control IMs drives took place when high performance drives is required.

7-

Till now, few industrial drives manufacturers adopt or fabricate DTC-based drives since the development of the first drive by ABB in 1996.

8-

MPC have not got the commercial or industrial acceptance till now. However, considerable research papers adopt and recommend the utilization of FCS-MPC in high performance IM drives.

9-

Modern IM drives have the option of regenerative braking to provide quick stopping and motor braking. Moreover, it participates in reduction in the overall energy consumption of the AC drive. In EVs and electric transportation systems, regenerative braking extend the distance range of the vehicle battery by trickle charging during EV speed reductions and stopping.