An Enhanced Power Quality and Smooth Transition Control Strategy for a Microgrid without Remote Pre-Synchronization Communication
Guo Huizhu1, Meng Xin1, He Mingzhi1, Liu Xueshan1, Liu Jinjun2
1. School of Electrical Engineering Sichuan University Chengdu 610065 China; 2. School of Electrical Engineering Xi'an Jiaotong University Xi'an 710048 China
Abstract：The paper proposes a smooth transition control strategy for microgrids with high power quality and no need for remote communication lines. The microgrid is mainly composed of multiple parallel distributed power generation units and a pre-synchronization unit. A unified grid-connected current control structure is proposed for the interface inverter in the distributed power generation unit, which has the following advantages: ① Without island detection, the inverter can automatically switch between the current control state of the grid-connected mode and the voltage control state of the stand-alone mode to ensure the load power supply quality; ② The proposed unified grid-connected current control structure can effectively suppress the harmonics in grid-connected current and capacitor voltage; ③ When the grid frequency fluctuates, the inverter can still output the corresponding active and reactive power according to the command value, and can synchronize with the grid without a phase-locked-loop or a frequency-locked-loop in the grid-connected operation state. In addition, the proposed pre-synchronization unit can realize the pre-synchronization control of the microgrid voltage and the grid voltage without relying on the remote communication lines. It also reduces the inrush current when the stand-alone operation state changes to the grid-connected operation state. Finally, the control parameters are optimized, and the effectiveness and feasibility of the proposed control strategy are verified through experiments.
郭慧珠, 孟鑫, 贺明智, 刘雪山, 刘进军. 无通信高电能质量的微电网平滑切换控制策略[J]. 电工技术学报, 2022, 37(10): 2611-2621.
Guo Huizhu, Meng Xin, He Mingzhi, Liu Xueshan, Liu Jinjun. An Enhanced Power Quality and Smooth Transition Control Strategy for a Microgrid without Remote Pre-Synchronization Communication. Transactions of China Electrotechnical Society, 2022, 37(10): 2611-2621.
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