Li, K.-Y.; Allen, T.; Bickerton, S.; Kelly, P. Thermal-Mechanical Behaviour of Road-Embedded Wireless Charging Pads for EVs. Appl. Sci.2023, 13, 12766.
Li, K.-Y.; Allen, T.; Bickerton, S.; Kelly, P. Thermal-Mechanical Behaviour of Road-Embedded Wireless Charging Pads for EVs. Appl. Sci. 2023, 13, 12766.
Li, K.-Y.; Allen, T.; Bickerton, S.; Kelly, P. Thermal-Mechanical Behaviour of Road-Embedded Wireless Charging Pads for EVs. Appl. Sci.2023, 13, 12766.
Li, K.-Y.; Allen, T.; Bickerton, S.; Kelly, P. Thermal-Mechanical Behaviour of Road-Embedded Wireless Charging Pads for EVs. Appl. Sci. 2023, 13, 12766.
Abstract
Road-embedded inductive power transfer (IPT) systems have the potential to accelerate the electrification of the transportation sector. For these systems to be economically viable however, they need to have a similar durability and lifespan compared to that of asphalt roads. One area that has lacked investigation is thermally induced stresses in a primary IPT pad, which is caused by the increase in temperature of the pad when it is energized and the differing thermal expansion of the materials within. This paper presents an experimental and a finite-element based methodology for investigating the thermal-mechanical behaviour of a ¼-scale double-D pad, which was energized while suspended in air, as well as energized when embedded in pavement. A focus was placed on the measurement and prediction of strains in the magnetic ferrite cores because of their brittleness. Ferrite strains were measured using a combination of resistive strain gauges and non-metallic Fibre Bragg Grating (FBG) sensors. Coupled electromagnetic-thermal-structural simulations were conducted to predict temperature and strains in the system, with temperature-dependent properties obtained through physical testing. At an ambient temperature of 50°C, the temperature in the middle of the copper litz wire coil was predicted to be 100°C in both the suspended and embedded case. There was excellent correlation to experimental results, with a difference of less than 10% for most temperature measurements. When energized, the pad was predicted to experience an upward bow due to its temperature rise, resulting bending strains in the ferrite cores. At an ambient temperature of 50°C, maximum tensile strain in the ferrites of the embedded pad was measured to be 62 microstrain (με), with a root-mean square error that was 18 με across three sensors. The experimental and validated numerical methodology can be applied to full-scale operational IPT pads to analyse and improve their thermal-mechanical performance.
Keywords
inductive power transfer; finite element analysis; Fibre Bragg Gratings; multi-physics simulations; experimental methodology; thermal strain; temperature measurement
Subject
Physical Sciences, Applied Physics
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
