混合级联型多电平变频器拓扑结构研究

多电平电路在高压大功率领域的拓展受到其复杂电路拓扑的制约，因此近年来不断有新型多电平电路结构被提出。该文对已提出的级联型多电平电路结构进行深入分析，对其中最具实用价值的混合七电平级联型变频器在PWM控制方法和整流电路结构上作出改进，解决了直流侧电流倒灌和整流侧电流谐波抑制的问题。在此基础上提出了3-10kV电压等级的混合级联型多电平变频器拓扑结构，并给出了仿真和实验结果。该混合级联型变频器符合目前电力电子器件发展特点，对传统级联型变频器在结构上作出了优化。

Research on the Topology of Hybrid Cascaded Multilevel Converters

The spread of multilevel converters in high- voltage and large-capacity fields is restrained due to complicated topologies, therefore some new topologies are proposed continuously in recent years. In this paper, a detailed ananysis of novel cascaded multilever converters is included. The PWM stategy and rectifier topology of hybrid cascaded converters, which have the most applicable value, is improved to solve the problems that the reverse current of DC bus and the harmonic suppression of rectifier. On this basis, the topology of hybrid cascaded multilevel converters for 3-10kV drives is proposed, and the simulation and experimental results are presented. The proposed converter accords with the develop character of the present semiconductor devices, and optimizes the conventional cascaded converter structure.