Coupled-Filter-Inductor Soft-Switching Techniques: Principles and Topologies

Pulsewidth-modulation inverters and rectifiers are required in widespread applications such as energy-storage power plants, telecommunication systems, and electric-vehicle propulsion systems. Some of the stringent requirements of these applications can be achieved by high switching frequency. On the other hand, the use of high switching frequency may degrade the overall system efficiency, which can be alleviated by the utilization of soft-switching techniques. In this paper, a generic soft-switching diagram that can generate topologies for turn-on snubber, zero- voltage transition, zero-current-zero-voltage transition inverters with coupled filter inductor is proposed. This approach facilitates the understanding of these techniques by both newcomers and senior engineers, making the advantages and disadvantages of each soft-switching technique much clearer.