Analysis and optimization of regenerative linear snubbers applied to switches with voltage and current tails

Among the trends notable in modern power electronic converters, the following two are of particular importance: the interest in and growing application of soft switching techniques and the widespread use of the newer device types, such as the IGBT. In this paper, a new approach to the optimization of total losses for these device types is proposed. To describe the tail-forming characteristics of devices such as the IGBT, GTO, and MCT better, the changing device parameters are modeled by two linear segments of different gradients. The switching losses of devices that exhibit tail characteristics are analyzed using this modeling approach. The snubber size is optimized for minimum total losses with respect to the recovery efficiency of the snubber circuit. The validity of the proposed description is confirmed by independent experimental results