The Flexible Interconnection Strategy between DC Microgrid and AC Grid Based on Virtual Electric Machinery Technology
Lan Zheng1, Tu Chunming2, Jiang Fei3
1. College of Electrical and Information Engineering Hunan University of Technology Zhuzhou 412007 China; 2. National Electric Power Conversion and Control Engineering Technology Research Center Hunan University Changsha 410082 China; 3. College of Electrical and Information Changsha University of Science and Technology Changsha 410082 China
Abstract：The interface converter of DC microgrid mostly adopt “rigid” control strategy, which is insufficient with inertia and damping. It causes the DC microgrid to lack a mechanism for flexible interconnection with the AC grid and cannot actively participate in the power regulation. In this paper, a flexible interconnection strategy between DC microgrid and AC grid based on virtual electric machinery technology is proposed. The interface converter adopts cascaded power electronic transformer, and both the ac side and the dc side integrate unified virtual motor control, simulating the operation characteristics of the rotating machinery. The DC microgrid exhibits flexible features, reduces the impact on AC grid caused by the internal power fluctuations, and improves the stability of the DC bus voltage. At the same time, the active and reactive power of the interface can be adjusted actively to support the frequency and voltage of the AC grid. The proposed flexible interconnection method has been verified by the simulation results in PSCAD/EMTDC.
兰征, 涂春鸣, 姜飞. 基于虚拟电机技术的直流微电网与主电网柔性互联策略[J]. 电工技术学报, 2019, 34(8): 1739-1749.
Lan Zheng, Tu Chunming, Jiang Fei. The Flexible Interconnection Strategy between DC Microgrid and AC Grid Based on Virtual Electric Machinery Technology. Transactions of China Electrotechnical Society, 2019, 34(8): 1739-1749.
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2019, Vol. 34 
