ISSN 1674-0629
CN 44-1643/TK
CN 44-1643/TK
Error-Free Control of Voltage/Frequency After Power Source Failure in Isolated Hybrid Microgrids
Jun LI , Naqin BAO , Jianhua CHEN , Ganyun LÜ , Yizhi CHEN
›› 2025, Vol. 19 ›› Issue (1) : 150 -159.
Error-Free Control of Voltage/Frequency After Power Source Failure in Isolated Hybrid Microgrids
Most of the interconnecting converters in island hybrid microgrids are grid-following converters, which change their control strategies to switch operation modes by means of remote communication order. When the system operation mode suddenly switches and communication failure or delay happens, the grid-following converters cannot quickly change the control strategies, resulting in voltage and frequency collapse. To solve the above problems, a new type of interconnected converter called grid-forming converter is introduced, which consists of a pair of back-to-back DC/DC and DC/AC converters. The grid-forming converter only needs local communication, and can complete seamless switching of operation modes by measuring and controlling the DC voltage on the DC-DC side, the voltage of interconnected capacitors and the AC frequency on the DC-AC side, and improves the resilience of hybrid microgrids operation. The small size magnitude drop of voltage or frequency will happen after microgrids operation modes switching due to the grid-forming converter control strategy supported by photovoltaic (PV) generations. So a coordinated control strategy between the grid-forming converter and the virtual DC motor energy storage is proposed. The simulation results show that the frequency of AC side and the voltage of DC side can be quickly stabilized at the rated value after the sudden failure of either side of AC/DC voltage sources in isolated island hybrid microgrids under the synergistic action of the grid-forming converter and virtual DC motor energy storage.
hybrid microgrids / error-free control / virtual DC motor energy storage / seamless switching of modes / grid-forming converter
the Carbon Peak and Carbon Neutral Technology Innovation Project of Jiangsu Province(BE2022003-4)
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