A 48 V, 1.5 kW, front-end zero-voltage-switched, PWM converter with lossless active snubbers for output rectifiers

A 48 V, 1.5 kW, zero-voltage-switched, phase-controlled PWM power converter for front-end application in a distributed power system is introduced. The converter operates at 150 kHz, employs lossless active snubbers for its output rectifiers, and achieves an efficiency of about 94% with an input voltage range from 330 V to 425 V. The active snubbers effectively eliminate the voltage spikes and ringings across the rectifiers. As a result, lower-voltage rectifiers can be used and a saving of approximately 45 W in conduction losses and snubber losses is obtained, as compared to using conventional RC snubbers. The implementation of the lossless active snubbers and its impact on the converter´s primary current are discussed