Semiconductor Power Losses Reduction Using Tandem Diodes Concepts for Motor Drives Applications

Generally, variable speed motor drives systems use Si-based chipset in standard sixpack topology with switching frequencies up to 16 kHz. Considering filter less implementations between converter and motor, hence, is required that dv/dt-stress on the motor windings should be limited up to 5 V/ns in order to avoid partial discharge phenomena or early insulation failure. The 1200 V pair IGBT and antiparallel freewheeling diode are selected by several figure-of-merit such as cost, efficiency, short circuit capability, EMC and so on. Concurrently, power losses and cost reduction are crucial for industrial motor drives, hence an investigation about optimal chipset is required. Tandem FWD pair has been proposed as an interesting chipset solution in parallel with standard 1200 V IGBT technology due to low reverse recovery losses coefficients from 650 V diodes technologies. An analysis of different chipset technologies demonstrates that Si-based tandem FWD are potentially solutions bringing an equilibrated trade-off in cost and performance for standard motor drives applications limited by dv/dt values below 5 V/ns. Experimental results validated the proposed investigation.