Analysis on Control Strategies for Unsymmetrical State of Medium Frequency Three Phase Four Leg Inverter Based on Vector Model
Chen Yihan1, Guo Honghao1, Chen Jie2, Wang Chengchao1, Ma Haixiao1
1. College of Automation Nanjing University of Posts & Telecommunications Nanjing 210023 China; 2. College of Automation Engineering Nanjing University of Aeronautics & Astronautics Nanjing 211106 China;
Abstract：Three phase four leg inverter has ability to work under unsymmetrical load, also has three phase decoupling character. However, control strategy based on analog circuit in middle-frequency applications is complex. In this thesis, based on control strategies,such as open loop, closed loop and three harmonic injection of fourth leg, vector model consists of voltage, current signals of main and control circuit also can be established. Relationship of control strategies of fourth leg and circuit parameters can be obtained by comparing control characteristics of fourth leg control strategies. In conclusion, it can be proved that third harmonic signal generated by output signals of three phase current loops can compensate most of zero-sequence component of fourth leg under unsymmetrical load. On this basis, in this thesis, the control strategy combines both third harmonic signal injection and closed loop control of fourth leg is proposed, it can not only guarantee the DC voltage utilization, but also improve the quality of output voltage under unsymmetrical load. Simulation and experiment results prove theoretical analysis is correct.
陈轶涵, 郭鸿浩, 陈杰, 王成超, 马海啸. 中频三相四桥臂逆变器控制策略不平衡负载状态相量模型分析[J]. 电工技术学报, 2019, 34(9): 1912-1923.
Chen Yihan, Guo Honghao, Chen Jie, Wang Chengchao, Ma Haixiao. Analysis on Control Strategies for Unsymmetrical State of Medium Frequency Three Phase Four Leg Inverter Based on Vector Model. Transactions of China Electrotechnical Society, 2019, 34(9): 1912-1923.
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2019, Vol. 34 
