Soft-switching push-pull converter with parallel resonant link and buck-boost capability

A partial resonant push-pull converter with buck-boost capability is proposed. Magnetizing inductance of the three-winding transformer and three capacitors are used to form a parallel LC resonant link. The capacitors create a Zero Voltage Switching (ZVS) condition at turn-on and reduce the turn-off loss for all switches. Although the converter is not current-fed, there is no dc offset in the input current, thereby eliminating the saturation problem that is common to conventional push-pull converters. An analytical approach is developed to establish a relationship between link parameters, input and output voltages, and link frequency. Experimental results are included to corroborate the design and operation.