Journal of Power Electronics

The Korean Institute of Power Electronics (전력전자학회)
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Active damping strategy with differential feedback of grid-side inductor voltage for LCL-filtered grid-connected inverters

  • Li, Mingming (College of Engineering, Southeast University) ;
  • Xiao, Hua F. (College of Engineering, Southeast University) ;
  • Cheng, Ming (College of Engineering, Southeast University)
  • Received : 2021.06.02
  • Accepted : 2021.11.24
  • Published : 2022.02.20
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Abstract

Active damping (AD) methods with extra feedback provide a high rejection of the resonance peak caused by LCL-filters, and have the advantages of simple implementation and strong robustness. Among them, capacitor current proportional-feedback AD has been proved to be effective and robust with only a proportional calculation. However, a large capacitive current pulsation restricts the detection accuracy. Based on a theoretical derivation, the same damping effect but with a better rejection of grid harmonic can be obtained by grid-side inductor voltage differential-feedback AD. However, the measured inductor voltage usually contains a parasitic resistance voltage that is difficult to separated, and it deteriorates the performance of LCL-filters. To solve this problem, a differential-negative proportional method based on the vector relationship between the voltages of the grid-side inductor and its parasitic resistance is proposed in this paper. In addition, the influence of control delays is considered and a solution is given. Experimental results based on a 3 kW LCL-type grid-connected inverter prototype are provided to verify the effectiveness of the proposed method.

Keywords

Acknowledgement

The study was funded by The National Natural Science Foundation of China (Grant no. 51577033) and Foundation of Jiangsu Provincial Key Laboratory of Smart Grid Technology and Equipment.

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