三电平ANPC逆变器改进SVPWM控制策略

An Optimized SVPWM Control Strategy for Midpoint Voltage Balance in Three-Level ANPC Inverter

针对三电平有源中点钳位逆变器(ANPC)中点电压不平衡问题,提出一种改进的SVPWM控制策略。首先,分析了ANPC逆变器中点电压不平衡的原因,利用空间矢量合成方法分析了各矢量形成的中点电流,从而提出了一种利用大矢量合成中矢量的改进调制算法,并且分析了SVPWM调制模式下中点电压的偏移情况,并提出了解决方案;在此基础上,对所提出的改进SVPWM控制策略和NVSVM控制策略进行了仿真对比,分析了改进算法的优势;最后,通过搭建实验平台对提出的算法进行了实验验证,实验结果表明:提出的控制策略能有效平衡中点电压,同时能及时地校正中点电压的偏移,中点电压波动小。

Aimed at the problem that midpoint voltage is out of balance in three-level active midpoint clamp inverter(ANPC),an improved SVPWM control strategy is proposed.Firstly,the reasons of the point voltage imbalance in the ANPC inverter are analyzed,the midpoint current formed by each vector is analyzed by the space vector synthesis method,and an improved modulation algorithm is proposed by using vector in large vector synthesis.The offset of midpoint voltage in SVPWM modulation mode is analyzed,and a solution is given.On the basis of this,the modified SVPWM control strategy and the traditional SVPWM control strategy are simulated and compared with others,and the advantages of the improved algorithm are analyzed.Finally,the results are verified by the experimental platform.The results show that the modified SVPWM control strategy can effectively balance with the midpoint voltage,and can correct offset to be the midpoint voltage in time,and can make the midpoint voltage weak in fluctuation.