Restraining Zero-Sequence Circulating Current of Directly Parallel Modular Inverters
Zhang Mingrui1, Song Baihui1, Lin Xianqi2, Ouyang Li3, Sun Hua3
1. Tongji University Shanghai 201804 China; 2. Qindao Sifang Rolling Stock Research Institute Co., Ltd. Qingdao 266112 China; 3. Central Academe, Shanghai Electric Group Co., Ltd. Shanghai 200070 China
Abstract:In the FREEDM microgrid, direct parallel inverter technology can improve the capacity of solid state transformers. However, there will be large zero-sequence circulating currents, due to the impacts of the zero drift of operational amplifiers, harmonic disturbances and signal delay. Based on the average model and synchronous rotating coordinate model of zero-sequence circulating currents among direct parallel inverters, this article analyses the relationship between dq0 reference signal and the output voltage. Then an ideal machine model is proposed, to regulate the reference voltage of PWM carriers with error feedback according to a certain order, and to realize the zero-sequence circulating currents restraining and power sharing. The case study in PSCAD/EMTDC shows that the control strategy can restrain the zero-sequence circulating currents effectively, and improve the accuracy of power sharing.
张明锐,宋柏慧,林显琦,欧阳丽,孙华. 直接并联模块化逆变器零序环流抑制[J]. 电工技术学报, 2015, 30(20): 100-107.
Zhang Mingrui, Song Baihui, Lin Xianqi, Ouyang Li, Sun Hua. Restraining Zero-Sequence Circulating Current of Directly Parallel Modular Inverters. Transactions of China Electrotechnical Society, 2015, 30(20): 100-107.
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