Analysis and comparison of a new passive lossless snubber for high frequency converter application

Two variations of a new adaptive turn on/off snubber configurations are developed where energy trapped in the snubber is fully recovered, passively, into the DC rail, in addition to the load, without any active devices or resistors. The circuit may be operated in a soft-clamped, or hard-clamped snubber mode. The circuit models are analyzed in detail and their relative circuit performances are compared. Besides individual advantages, the two variations of the snubber posses the common characteristics that maximum over-shoot voltage on the switch is fixed, peak switch current is low and the operational range of load current is wider than conventional snubbers. The application of the two variations of the snubber, for use in high frequency power converters, is discussed and design equations are given, along with simulations and experimental results for an IGBT converter