五电平逆变器的电容电压平衡算法

The Capacitor Voltage Balance For The Optimization of Five Level Inverter

介绍了五电平中性点箝位H桥换流器,其中包含12脉冲整流器.研究了整流器和逆变器中性点连接的两种结构:第一种结构中性点断开和第二种结构中性点连接.此外,提出一种新的适用于当前结构的中性点电压平衡方法,给出了大量的中性点电压平衡的仿真结果.仿真结果要应对一些问题如逆变器输出电流的总谐波失真(THD)和电压、电流、频率、谐波含量、频谱分布.结果证实了所提出的方法的有效性.比较了电压平衡的方法,并对它们的优缺点进行了说明.

The paper presents the 5-level,neutral point clamped,H-bridge inverter fed by 12-pulse rectifier.Two configurations of rectifier and inverter neutral point connection are studied,the first configuration with disconnected neutral points and the second configuration with connected neutral points.Furthermore,novel neutral point voltage balancing methods suitable for the presented configurations are proposed.Extensive simulation results of the proposed configurations with the neutral point voltage balancing methods are presented.The simulation results deal with aspects such as total harmonic distortion（THD）factor of the inverter output currents,and voltages,grid current,harmonic content,frequency spectrum distribution.The results confirm the effectiveness of the proposed methods.The voltage balancing methods are compared and their advantages and disadvantages are explained.