1.State Key Laboratory of Advanced Electromagnetic Engineering and Technology (Huazhong University of Science and Technology), Wuhan 430074, China;2.Guangdong EAST Power Co., Ltd., Dongguan 523808, China
During the traditional pre-synchronization process for grid-connection of islanded microgrids, there exist the voltage fluctuation caused by the output variation of the wind and photovoltaic distributed generators, and the frequency out-of-limit risk caused by the improper proportional-integral (PI) parameters. To solve the above problems, firstly, the feedforward disturbance compensation of the load voltage and current is introduced into the V/f control strategy of the energy storage system to suppress the voltage fluctuation. Secondly, based on the Simplex algorithm, the PI parameters are optimized to take into account the grid-connected speed and frequency fluctuation in the pre-synchronization process, and the optimized PI parameter selection method combining off-line optimization and on-line lookup table is designed. Thirdly, a pre-synchronization optimized control scheme for the islanded microgrid considering both the voltage fluctuation and frequency out-of-limit risk is proposed. Finally, the simulation experiment proves that the pre-synchronization scheme for the grid connection of islanded microgrids can realize the fast phase synchronization and effectively suppress voltage fluctuation and avoid frequency out-of-limit risk.
This work is supported by National Key R&D Program of China (No. 2018YFB0904100).
|||WU Yuqi, YE Yuqing, MA Xiao, et al. Pre-synchronization Scheme with Voltage Fluctuation Suppression and Frequency Out-of-limit Avoidance for Grid Connection of Islanded Microgrid[J]. Automation of Electric Power Systems,2021,45(14):56-64. DOI:10.7500/AEPS20201104009|