一种新型五电平逆变器电容电压平衡策略研究

Research on Capacitor Voltage Balance Strategy of Novel Neutral-point Clamped Five-level Inverter

以一种新型有源中点筘位型五电平逆变器拓扑为研究对象,分析了其工作原理,重点研究了其开关状态对母线中点电压和悬浮电容电压的影响。在此基础上提出一种最优开关组合控制策略,基于最优函数的思想选择合适的冗余开关状态组合实现电容电压的平衡控制。仿真和实验验证了所提出的平衡控制策略的有效性。所提平衡思想与控制策略可广泛应用于各种有源中点箝位型拓扑,具有较强的推广性与实用性。

The working principles,especially the effects on capacitors voltage of different switching states,of a novel neutral-point clamped three-phase five-level clamped topology is studied.And then an optimal switching states combination control strategy is proposed,which selects the redundant switching states due to the capacitors voltage balance.The effectiveness of the proposed strategy has been tested and verified in both simulations and experiments.Meanwhile,the proposed balance control strategies can be widely used in active neutral clamped topology.