Abstract：A typical micro-grid control strategy is generally feed-forward decoupling constant power(PQ) control based on equilibrium assumption. Through the power analysis on the micro-grid control strategy and analysis of grid-connected inverter output performance using switching function, it could come to the conclusion that the output of the inverter consists of third harmonic and negative sequence components based on the control strategy of equilibrium assumption under the condition of voltage unbalance on the grid. In order to improve the performance, a feed-forward negative sequence voltage control loop is used to superimpose on the original PQ control structure, achieving the purpose of offsetting voltage negative sequence component in the grid and maintaining three-phase balance. Also, the system could suppress the output of the third harmonic through the improved switching function modulation method. The simulation and experiment results indicate that the improved micro-grid unbalanced PQ control strategy may improve the survival capacity of micro-grid under asymmetrical grid voltage.
易桂平. 电网电压不平衡条件下微网恒功率控制策略研究[J]. 电工技术学报, 2015, 30(14): 377-387.
Yi Guiping. Micro-grid Constant Power Control Strategy Analysis under Grid Voltage Imbalance. Transactions of China Electrotechnical Society, 2015, 30(14): 377-387.
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