阶梯波合成Ⅱ型混合级联多电平逆变器的功率均衡策略

Power Balance Strategy for Staircase Waveform Synthesis of Ⅱ-Type Hybrid Cascaded Multilevel Inverter

揭示了混合级联多电平逆变器实现功率均衡所需满足的条件:各单元输入平均功率应与其对应输入电压成正比。提出了可以实现功率均衡的改进型阶梯波合成控制,并对所提均衡策略进行讨论,指出其突出优点是:无论级联单元个数多少,逆变器实现功率均衡所需的时间仅为一个输出周期,但逆变器输出电压波形质量会受到一定的影响。最后将该均衡策略推广至一般形式。实验结果验证了该均衡策略的可行性。

This paper reveals the power balance principle of the hybrid cascaded multilevel （ML） inverter, which requires that the input average power of each cell must be proportional to the corresponding input voltage. In order to realize power balance, this paper proposes an improved staircase waveform synthesis strategy. After detailed discusses, it points out the prominent advantage of the proposed strategy is no matter how many cells there are cascaded, it can ensure the output power of each cell well balanced in only one output cycle, but it will affect the total harmonics distortion （THD） of the output voltage a little. Finally, this paper gives out the common equations of the proposed power balance strategy for any cascaded cells. Experimental results verify the validity of the proposed strategy.