采用不可控整流的混合不对称多电平变换器控制策略

混合不对称多电平变换器在输出相同电平数的情况下较传统多电平变换器采用更少的功率元件，可以大大减少变换器体积与成本，成为近年来研究的热点，但至今还没有统一的设计标准和方法。对采用不可控整流的混合不对称多电平变换器进行了深入的研究，通过对采用混合控制策略下的不对称多电平变换器输出电压及各单元输出功率的分析，提出避免有功功率双向流动的控制方法，并在此基础上总结了在进行混合不对称多电平变换器设计时需要遵循的一些原则。对典型的混合不对称三单元变换器进行了仿真与试验验证，仿真与试验结果表明所得结论正确。

Control Method of Hybrid Asymmetrical Multilevel Converter With Unidirectional Rectifier

In recent years, hybrid asymmetrical multilevel converters have received more attentions because they need less power devices than conventional multilevel converters when the number of output voltage levels is same, and the volume and cost are reduced evidently. However, a generalized design and methodology has not yet been presented. A detailed analysis of hybrid asymmetrical multilevel converters with unidirectional rectifiers was given. A new control method was presented by analyzing the output voltage and output active power of cells to avoid active power regenerated to the input source. Some design principles for hybrid asymmetric multilevel converters were given. Simulations and tests were carried out on a typical three-cell hybrid asymmetric multilevel converter and the results show the conclusions are correct.