A Parallel Resonant DC Link Inverter With Low Current Stress on Main Switch

The resonant current of the resonant dc link inverter is superimposed on the main switch in periods of the zero-voltage notch creation, which increases the current stress as well as the conduction loss of the main switch, and inevitably escalates the selection cost of the main circuit. To solve these problems, a parallel resonant dc link inverter with low current stress on main switch is proposed in this article. The main switch of this inverter does not need parallel resonant capacitors, and it also ensures that the current of the main switch remains at the load current value during the whole resonance process or the zero-voltage notch, thus effectively reduces the current stress of the main switch, and thereby the hardware cost of the main circuit can be further diminished. At the same time, the conduction loss of the main switch is significantly decreased since the resonant current is no longer considered, thus improving the efficiency of the inverter. The operation principle of this circuit is analyzed and compared with existing literatures and the design method is also given in the article. Finally, the effectiveness of this resonant dc link inverter is experimentally verified.