Loss Minimization by Partial SAZZ for High-Power Chopper

抄録

Loss minimization is vital in high-power choppers for electric drive systems in automobiles. This paper describes the evaluation of partial turn-off behavior in IGBTs (Insulated Gate Bipolar Transistor) by ZVS (Zero Voltage Switching) without over-elimination based on Partial SAZZ (Snubber Assisted Zero Voltage and Zero Current Transition). High power BTB (back to back) experiments using a 90kW 3-phase interleaved chopper derived the good characteristics of the Partial SAZZ method and compared them with those of the hard switching (Hard SW) method. The total switching loss of the main circuit, which accounted for 48% (674W) in Hard SW, reduced to 192W, a 72% reduction, in Partial SAZZ. The Partial SAZZ method obtained the highest efficiency of 97.42% at 30kW, 1.82% higher than Hard SW (95.6%) and the highest efficiency over the entire power region. This was verified through a load test and loss breakdown of up to 30kW per phase.