降低共模电压的三电平变流器SVPWM策略

A novel virtual space vector modulation with reduced common mode voltage and eliminated neutral point voltage oscillation for neutral point clamped three-level inverter

文章简要回顾了中点箝位型(neutral point clamped,NPC)三电平逆变器(three-level inverter,TLI)(NPC TLI)的共模电压(common mode voltage,CMV)和中点电压(neutral point voltage,NPV)的相关问题,针对上述2个问题讨论了空间矢量脉宽调制(space vector pulse width modulation,SVPWM)和传统虚拟SVPWM(VSVPWM),揭示了它们在减小共模电压和消除中点电压振荡方面的不足。为了同时实现降低NPC TLI的共模电压和消除其中点电压振荡,提出了一种新的虚拟空间矢量调制方法,即RCMV-VSVPWM。通过选取低共模电压的矢量,得到了一组新的虚拟电压矢量。该方法具有一个控制周期内平均中点电流为0、共模电压低的特点。文中进一步提出了一种适用于RCMV-VSVPWM的中点电压主动控制方法。相应实验结果与理论分析吻合。

This paper briefly reviews the common mode voltage(CMV)and neutral point voltage(NPV)of neutral point clamped three-level inverter(NPC TLI).Then,the space vector pulse width modulation(SVPWM)and traditional virtual SVPWM(VSVPWM)are discussed in term of these two issues,revealing the shortcomings in reducing CMV or eliminating NPV oscillation.To reduce CMV and eliminate NPV oscillation for NPC TLI simultaneously,a novel virtual space vector modulation,called as RCMV-VSVPWM,is proposed in this paper.By selecting vectors with lower CMVs,a set of novel virtual voltage vectors are generated.The method is featured with zero average neutral point current in one control cycle and low CMV.Further,the active NPV control suitable for RCMV-VSVPWM is presented.The corresponding experimental results are given,which are well consistent with the theoretical analysis.