The effect of switching losses on the efficiency of a switch mode power converter and methods adopted for its improvement using an energy recovery lossless snubber has been presented. A comparative analysis of various types of soft switching techniques along with effects of dissipative and nondissipative snubbers on efficiency of the converter has been carried out before zeroing in on the selected scheme. The selected snubber serves the dual function of a turn-on and turn-off snubber and thereby reducing the switching losses both during turn-on and turn-off transients, resulting in improved efficiency of the converter. A detailed design procedure of the snubber for high-power applications taking into account various effects such as diode reverse recovery, diode voltage stress, and minimum and maximum duty cycle limits, has been presented in this paper. Importance of practical aspects in layout to minimize wiring inductance is also highlighted. A high-power prototype of buck converter has been developed to experimentally validate the theoretical design and analytical observations. 1. Introduction Switch mode power supplies are popular because of higher efficiency, smaller size, and lighter weight [1, 2]. Low weight and smaller size comes about because operation is significantly at a higher frequency range, and thus the magnetic components are quite smaller in size and weight [3]. High switching frequencies in turn results in large switching losses and stresses in power device because during the turn-on and turn-off transients the power device has to withstand high voltage and current simultaneously [4, 5]. Large and transitions also induces significant amount of electromagnetic interference (EMI) in the circuit which in turn pollute the utility systems [6]. This problem, if left unattended, may result in lower efficiency and larger size of converters owing to increased size of the heat sinks and EMI filters. Efforts are made in order to alleviate the aforementioned limitations and to enable operation at still higher frequencies while maintaining better conversion efficiency [7]. Snubbers are an essential part of power electronic systems. They are small network of passive components which forms a part of power switching circuits to reduce switching losses and stresses in power devices [8]. But, as the switching losses in the main switch are dissipated in form of heat in snubber resistors, the overall efficiency of the converter is deteriorated. Various soft switching techniques have been proposed in the literature [1, 9, 10] to obtain soft switching of
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