Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

# An Improved Droop Control Strategy for Grid-connected Inverter Power Stability and Harmonic Suppression Under Grid Fluctuation and Inter-harmonics

Version 1 : Received: 3 June 2021 / Approved: 4 June 2021 / Online: 4 June 2021 (10:48:27 CEST)

How to cite: Xu, W.; Wang, B.; Liu, J.; Li, D. An Improved Droop Control Strategy for Grid-connected Inverter Power Stability and Harmonic Suppression Under Grid Fluctuation and Inter-harmonics. Preprints 2021, 2021060136 (doi: 10.20944/preprints202106.0136.v1). Xu, W.; Wang, B.; Liu, J.; Li, D. An Improved Droop Control Strategy for Grid-connected Inverter Power Stability and Harmonic Suppression Under Grid Fluctuation and Inter-harmonics. Preprints 2021, 2021060136 (doi: 10.20944/preprints202106.0136.v1).

## Abstract

This paper presents an improved droop control strategy for grid-connected inverter power stability and power quality under distorted with consideration of grid fluctuation and inter-harmonics. An instantaneous frequency without PLL and amplitude of capacitor voltage feed-forward control strategy is given to power stability control, meanwhile a grid current feedback control is given by an incomplete derivation with a high-pass filter, so that the harmonics and inter-harmonics current can be suppressed. These approaches can provide both good active and reactive power dynamic response under fluctuation of frequency, and rejection ability against harmonic and inter-harmonic voltage. Based on model of inverter, the proposed control strategies are designed in detail. Simulations and experiments are present to validate the effectiveness of proposed method.

## Subject Areas

Droop control; micro-grid inverter; grid-connected mode; instantaneous frequency detection; incomplete derivation

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