直流母线串联辅助电路的谐振直流环节逆变器

为实现一种结构简单,控制方便,高效率,高功率密度的逆变器,提出了一种新型谐振直流环节软开关逆变器的拓扑结构。通过在传统硬开关逆变器的直流环节添加串联在直流母线上的辅助谐振单元,使直流母线电压周期性地归零,可以实现逆变桥主开关器件的零电压开关,而且辅助开关器件可以实现零电流开通和零电压关断。此外,辅助谐振单元只有一个辅助开关,硬件成本低。分析了电路的换流过程和设计规则,并建立起辅助谐振电路损耗的数学模型,讨论了谐振参数对辅助电路损耗的影响。制作了一个1 k W的实验样机,实验结果表明逆变器的主开关和辅助开关器件都实现了软开关,所以该软开关逆变器能有效地降低开关损耗和提高效率。

Resonant DC link inverter with series auxiliary circuit on DC bus

A novel resonant DC link soft-switching inverter was proposed to realize a inverter which has a simple topology,an easy control strategy,high efficiency and high power density.Series auxiliary resonant unit on the DC bus was added to DC link of conventional inverter to make DC-bus voltage decrease to zero periodically,which realized zero-voltage operation of all switching devices in inverter.Furthermore, the switching device in the auxiliary resonant unit could be turned on under zero-current and turned off under zero-voltage.In addition,because only one auxiliary switch was in the auxiliary resonant unit,cost of hard-ware was lower.Commutation process of the circuit and design rule were analyzed.The mathematical mod-el for auxiliary resonant circuit loss was established and the influence of resonant parameters on the loss of auxiliary circuit was discussed.A 1 kW laboratory prototype was built.The experimental results demonstrat that soft-switching operation of all switching devices can be realized.Therefore,the soft-switching inverter presented can effectively reduce switching loss and improve efficiency.