Some design aspects of fully and partially regenerative active snubber networks

Analytical expressions predicting the energy trapped in snubber network components are developed. These expressions are then used to evaluate the effectiveness of frequently used low-loss snubber networks under full and partial energy recovering conditions. Results show that the additional complexity of a fully regenerative active snubber is not always justified. Depending upon specific operating conditions and snubber component size, zones of yes, no, and maybe exist. The validity of predicted results have been verified on a 30 kVA GTO (gate turn-off thyristor) experimental inverter