Active auxiliary resonant snubber-assisted soft-switching PWM inverter with optimum gate pulse pattern sequences and its PV-system application

This paper presents an advanced circuit topology and optimum gate pulse patterns for the voltage source bridge type soft-switching PWM inverter, which incorporates a novel active auxiliary bridge commutation leg, associated quasiresonant snubbers as the improved ARCP snubber. In this voltage source type PWM inverter, all the main power switches and the auxiliary power switches can achieve the zero voltage soft-switching (ZVS) or the zero current soft-switching (ZCS). And the periodic steady state circuit operation of this quasiresonant bridge leg link snubber including the auxiliary switch is required to achieve the soft-switching commutation. The complete soft-switching commutation is possible only by determining the gate timing of the main switches and the auxiliary switches, and the circuit parameter design. So the special resonant current and the current and voltage sensor control circuit to achieve soft-switching commutation are not necessary for this resonant snubber. In addition, the optimum gate pulse pattern to minimize the power losses of the resonant snubber treated here. The DC divided middle point composed of the electrolytic capacitor is unnecessary.