A soft switcher optimized for IGBTs in PWM topologies

A novel soft switching scheme optimal for power IGBTs is described and investigated theoretically and experimentally. The proposed soft switcher applies an auxiliary IGBT switch which is operated for a short time interval during the turn off commutation of the main IGBT. The main advantage of the proposed switcher is ZCS of the main and auxiliary IGBTs during both turn on and turn off while all other power devices are also soft switched. The proposed soft switcher can be implemented in various types of PWM topologies. The experimental boost power converter was run at a switching frequency of 100 kHz to power levels of 1 kW. The efficiency was measured to be about 95% with a duty cycle of 0.45 and an output voltage of 300 V.<>