Study of Control Strategy for Seamless Transfer of Grid-Connected Distributed Generation Systems
Wang Xiaohuan, Zhang Chunjiang
Key Lab of Power Electronics for Energy Conservation and Motor Drive of Hebei Province Institute of Electrical Engineering Yanshan University Qinhuangdao 066004 China
Abstract：The dual-mode inverters for distributed generation (DG) systems can operate in grid-connected and stand-alone mode. When the DG transfer the mode between the grid-connected and stand-alone mode, the control mode changes between the voltage control in stand-alone mode and current control in grid-connected mode. The key technology of dual-mode inverter is to achieve the seamless transfer and reduce the impact of current and voltage. During process of the transfer, the traditional seamless transfer control algorithm neglect non-synchronization of two kinds of transition, which address the issue of seamless transition assuming the work mode switching and control mode switching at the same time to complete. If ignoring the situation, it will cause voltage and current overshoot, which is unfavorable to power grid and load. After the transfer transient is detailed analyzed, this paper presents a voltage and current weighted control strategies without increasing system complexity. The strategy can ensure that the switching transient variables can be controlled to reduce the impact of voltage and current, and achieve seamless transfer. Simulations and experiments results verify the availability and correctness of the proposed method.
王晓寰, 张纯江. 分布式发电系统无缝切换控制策略[J]. 电工技术学报, 2012, 27(2): 217-222.
Wang Xiaohuan, Zhang Chunjiang. Study of Control Strategy for Seamless Transfer of Grid-Connected Distributed Generation Systems. Transactions of China Electrotechnical Society, 2012, 27(2): 217-222.
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