An Improved Resonant DC-Link Inverter to Reduce Switch Current Stress

During the resonant process, the resonant element of the resonant dc-link inverter (RDCLI) auxiliary resonant circuit (ARC) resonates with the shunt capacitors of the main switch, which will increase the current stress of the main switch and affect the waveform quality of the output waveform. To address this problem, this article proposes an improved RDCLI. Compared with the original RDCLI, this inverter simplifies the topological complexity of the ARC by reducing the switching devices. In the meanwhile, the main switch does not require shunt capacitors, so there is no resonant current in the main switch. In addition, during the zero-voltage notch, the resonant current also does not flow through the main circuit. So, this proposed inverter lowers the current stress in the main switch, which further improves the waveform quality. The working principle of the improved RDCLI and the design method are given in detail in this article, and the corresponding experimental results are also given at the end of this article.