三相H7电压源型光伏并网逆变器共模电压抑制

Common Mode Voltage Suppression for Three-phase H7 Voltage-source Photovoltaic Grid-connected Inverter

针对典型三相非隔离型光伏并网逆变器(以下简称"典型逆变器")存在共模电压的问题,在分析了共模电压与开关状态之间关系的基础上,提出采用具有7开关的三相H7电压源型光伏并网逆变器(以下简称"H7逆变器")拓扑和5段式空间矢量脉冲宽度调制技术,通过控制零矢量来抑制共模电压,并阐述了调制策略的实现方法。应用MATLAB/Simulink和MATLAB/Powergui平台对典型逆变器和H7逆变器进行仿真对比,典型逆变器和H7逆变器的共模电流有效值分别为0.716 A和0.411 A,且前者的共模电压基波幅值大于后者的共模电压基波幅值,说明所提方法能有效抑制共模电压。

In allusion to the problem of common voltage in typical three-phase non-isolated photovoltaic grid-connected in-verter （thereafter as typical inverter）, this paper proposes a modulation strategy for suppressing common voltage by control-ling zero vector, which is to adopt topology of three-phase H7 voltage-source photovoltaic grid-connected inverter （thereaft-er as H7 inverter） with seven switches and use five-segment space vector pulse width modulation technology on the basis of analyzing relationship between common voltage and switching state. Meanwhile, it states realization method for modulation strategy. By means of MATLAB/Simulink and MATLAB/Powergui platforms, it performs simulation comparison on the typical inverter and H7 inverter and figures out effective values of common current of these two inverters are respectively 0. 716 A and 0. 411 A. Fundamental wave amplitude of the former common voltage is greater than that of the later, which indicates the proposed method can effectively suppress common voltage.