二极管箝位五电平Z源逆变器研究

Study on Diode-Clamped Five-level Z-source Inverter

为了将Z源逆变器的单级变流特性应用于高压大功率场合,克服双Z网络二极管箝位五电平Z源逆变器所需储能元件多、硬件成本高及调制复杂的缺点,提出一种单Z网络结构的二极管箝位五电平拓扑,该拓扑只需一个Z网络,但通过合适的脉宽调制可以达到与双Z网络相同的升压效果。给出Z源逆变器直流链全直通及部分直通原理,分析适用于五电平Z源逆变器的直通控制方法,设计了直通状态插入的同向载波层叠(D)及交替反向载波层叠(APOD)两种脉宽调制策略。最后仿真验证系统直通控制方法及调制策略的正确性。

Existing five-level Z-source inverters use two LC impedance networks can significantly increase the overall system cost with numerous passive elements and require a more complex modulator. To overcome these disadvantages and apply the characteristic of single-stage energy conversion in high-power high-voltage application, a topology of diode-clamped five-level Z-source inverter with single impedance network is proposed. It only needs a single LC impedance network, with proper modulation, while achieving the same voltage boost capability like the topology with dual impedance networks. The basic principles of full dc-link shoot through and partial dc-link shoot through in Z-source inverter were given, and a shoot through control method matched for the proposed topologic was analyzed, carrier-based phase disposition （PD） and alternative phase opposite disposition （APOD） technique with shoot-through states inserted were designed. The correctness of shoot-through method and the modulation strategies were verified lastly by simulation.