A Novel Stability Improvement Strategy for a Multi-Inverter System in a Weak Grid Utilizing Dual-Mode Control

Energies

卷:11

Xing Zhang¹  Ming Li¹  Wei Zhao² 

[1] School of Electrical Engineering and Automation, Hefei University of Technology, Hefei 230009, China;

[2] Sungrow Power Supply Co., Ltd., Hefei 230088, China;

关键词: current source mode (CSM);    distributed generations;    grid-connected inverter;    grid impedance;    multi-inverter system;    voltage source mode (VSM);    weak grid;   

DOI  :  10.3390/en11082144

来源: DOAJ

【 摘 要 】

Due to the increasing penetration of distributed generations (DGS) and non-negligible grid impedance, the instability problem of the multi-inverter system operating in current source mode (CSM) is becoming serious. In this paper, a closed-loop transfer function model of such a multi-inverter system is established, by which it is concluded that output current resonance will occur with the increase in the grid impedance. In order to address this problem, this paper presents a novel dual-mode control scheme of multiple inverters: one inverter operating in CSM will be alternated into voltage source mode (VSM) if the grid impedance is high. It is theoretically proved that the coupling between the inverters and the resonance in the output current can be suppressed effectively with the proposed scheme. Finally, the validity of the proposed theory is demonstrated by extensive simulations and experiments.

【 授权许可】

Unknown