级联多电平逆变器CPS-TPWM策略研究

Research on CPS-TPWM strategy for cascaded multilevel inverter

针对传统的多电平调制策略直流电压利用率低的问题,提出了一种用于级联多电平逆变器(CMI)的载波相移梯形波脉宽调制(CPS-TPWM)策略。在对载波相移技术进行数学分析的基础上,推导了梯形波三角化率σ与CMI输出基波幅值和谐波含量的数学关系。在选取合适的σ值和拥有良好谐波特性的条件下,该调制策略大幅提高了CMI的输出电压基波幅值。在Matlab/Simulink中搭建了三相九电平CMI模型进行仿真验证,仿真结果证明了该方法的正确性和可行性。

For the issue of the low utilization rate of direct current （ DC ） voltage with the traditional multilevel modulation strategy, a carrier phase shifting trapezoidal pulse width modulation （ CPS- TPWM ）strategy for the cascaded multilevel inverter （ CMI） is proposed here. The relation of the trapezoidal wave triangular factor σ with the fundamental amplitude and the harmonic content of the CMI output is deduced based on the mathematical analysis of the carrier phase shifting technique. By choosing the appropriate cr value and making the CMI process possessing the better harmonic per-formance, the fundamental amplitude of output voltage is greatly improved by the proposed modulation strategy. A three-phase nine-level CMI model is built by the Matlab/Simulink, and the simulation results verify the correctness and the feasibility of the proposed method.