Control Strategy of LCL Grid-Connected Inverter Based on Improved Weighted Current Control

doi:10.3969/j.issn.1008-0198.2023.02.007

Hunan Electric Power ›› 2023, Vol. 43 ›› Issue (2): 39-45.doi: 10.3969/j.issn.1008-0198.2023.02.007

• Researches and Tests • Previous Articles Next Articles

Control Strategy of LCL Grid-Connected Inverter Based on Improved Weighted Current Control

LING Zhiyong^1,2, ZHOU Zhifei^1,3, LI Shengqing^1,3, YAO Hongde^1,3

1. School of Electrical and Information Engineering, Hunan University of Technology, Zhuzhou 412007,China;
2. State Grid Zhuzhou Power Supply Compnay, Zhuzhou 412000,China;
3. Hunan Engineering Research Center of Photovoltaic Microgrid Intelligent Control Technology, Zhuzhou 412007,China

Received:2022-11-11 Revised:2022-12-14 Online:2023-04-25 Published:2023-05-06

Abstract

Abstract: Aiming at the problems that the traditional weighted average current (WAC)control strategy does not consider the digital control delay, and causes the phase lag of the system, which leads to the reduction of system bandwidth and poor robustness, the WAC control strategy of combination of quasi-proportional resonance control and lead compensator is proposed. Firstly, the capacitor current feedback is introduced to suppress the reverse resonance peak. Secondly, the lead compensator is connected in series at the transfer function of the inverter bridge to improve the phase margin of the system. Finally, the quasi-proportional resonant controller is used as a current regulator to Increase the fundamental frequency gain and reduce the static error of the system. It is verified by simulation that the proposed control strategy has good adaptability to weak power grids, and the harmonic distortion rate of grid-connected current is reduced from 1.84% to 0.26%, thereby enhancing the robustness of the system and improving the quality of grid-connected current.

Key words: weighted current control, digital control delay, capacitive current feedback, system order reduction, quasi-proportional resonance control

CLC Number:

TM464

LING Zhiyong, ZHOU Zhifei, LI Shengqing, YAO Hongde. Control Strategy of LCL Grid-Connected Inverter Based on Improved Weighted Current Control[J]. Hunan Electric Power, 2023, 43(2): 39-45.

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Control Strategy of LCL Grid-Connected Inverter Based on Improved Weighted Current Control

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