Abstract：The isolatedisland microgrid has no large grid support, and the source-load power electronic equipment is strongly interactively coupled, which is prone to stability problems such as high frequency oscillation. In this regard, the impedance reconstruction control method of the isolated island inverter is proposed, which can improve the phase of the output sequence impedance of the isolated island inverter at high frequency, increase system damping and effectively suppress the high frequency oscillation of the system. A small-signal wideband positive and negative sequence impedance model of the off-grid source PWM inverter is established by using the harmonic linearization method. In order to further analyze the interaction stability of the island system, the positive and negative sequence impedance model of the load PWM rectifier is established. Then, according to the established impedance model and Nyquist stability criterion, the influence of control method, load type and load power on the stability of the isolated island microgrid system is analyzed. The essential reason for the high frequency oscillation of the isolated island inverter and the PWM rectifier type load interaction in the island microgrid is revealed: the output impedance of the isolated island inverter is negatively resistive-capacitive at high frequency, and the input impedance of the PWM rectifier type load is Inductive, causing the system impedance ratio not to meet the stability criteria. The proposed impedance reconstruction control method can improve the phase characteristics of the isolated island inverter at high frequencies and increase the stability of the system by adding the voltage feedback branch.Finally, the experiment verifies the correctness of the analysis in this paper.
刘津铭, 陈燕东, 伍文华, 张焜, 罗安. 孤岛微电网序阻抗建模与高频振荡抑制[J]. 电工技术学报, 2020, 35(7): 1538-1552.
Liu Jinming, Yan Dongchen, Wu Wenhua, Zhang Kun, Luo An. Sequence Impedance Modeling and High-Frequency Oscillation Suppression Method for Island Microgrid. Transactions of China Electrotechnical Society, 2020, 35(7): 1538-1552.
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2020, Vol. 35 
