考虑吸收电路的五电平有源中点钳位变频器电压过零切换策略

Optimization of voltage zero crossing switching strategy for 5L-ANPC inverter considering snubber circuit

五电平有源中点钳位(five-level active-neutral-point-clamped,5L-ANPC)变频器拓扑结构简单,可直接通过公共直流母线供电,易于实现能量回馈,非常适合用于5~10 kV直流供电的船舶推进变频调速领域。简要介绍了5L-ANPC的主电路拓扑和工作原理,针对5L-ANPC拓扑杂散参数较大的四种换流回路,在兼顾可靠性及适装性前提下,设计了纯电容吸收电路。在上述基础上,分析了设置吸收电路后的5L-ANPC拓扑采用传统电压过零切换策略时存在的内开关管过压问题,并提出一种考虑吸收电路的切换策略,实现了输出电压过零器件安全切换,且避免了电压异常跳变。通过仿真和实验验证了所提考虑吸收电路的输出电压过零切换策略的有效性、正确性。

The topology of 5L-ANPC(five-level active-neutral-point-clamped)converter has a simple structure,which can be directly supplied by the common direct current bus,and is easy to realize energy feedback.It is very suitable for the 5~10 kV propulsion variable frequency speed regulation in the integrated power system of ship.The topology and basic working principle of 5L-ANPC were briefly introduced.Based on the analysis of four commutation circuits of 5L-ANPC topology and considering the assembly and adaptability of the snubber circuit,a single capacitor integrated snubber circuit was designed.The over-voltage problem of internal switch in 5L-ANPC topology with snubber circuit using traditional voltage zero crossing strategy was analyzed and an improved output voltage zero crossing switching strategy was proposed,which ensure the safety of switching device and avoid the abnormal voltage jump.The effectiveness and correctness of the improved strategy are verified by simulation and experiment.