A comparison of voltage-mode soft-switching methods for PWM converters

A comparison study was conducted to characterize the loss mechanisms, component stresses, and overall efficiencies of a group of voltage-mode soft-switching pulse width modulation (PWM) methods, including two methods developed by the authors. All soft-switching methods in the selected group allow zero voltage turn-on and turn-off of the main switch and utilize a single auxiliary switch with some resonant components. Advantages and disadvantages are identified for each method. Experimental verification for each soft-switching method is provided. It was found that only those methods that softly switch the auxiliary switch, minimize redirection current, and recover the auxiliary circuit energy improved efficiency over most of the load range.