Series Connection of 10 kV SiC Current Switches for PWM Current Source Converter Based High Power 7.2 kV Motor Drive Applications

For the first time, two series-connected 10 kV SiC reverse-blocking switch (referred to as the current switch in this paper) consisting of the recently developed 10 kV SiC MOSFET and 10 kV SiC diode is proposed and experimentally demonstrated for a pulse width modulated current source inverter (PWM-CSI) based 7.2 kV motor drive applications. A passive RC snubber-based voltage balancing circuit is demonstrated to show excellent voltage sharing in the hard-switched conditions. The series-connected 10 kV current switch is characterized up to 6 kV blocking voltage. The experimental results show 98.6% efficiency at 10 kHz switching frequency for the 7.2 kV, 150 kVA PWM-CSI motor drive. The high switching frequency results in a 24 times smaller dc link inductor than the 6.5 kV silicon SGCT-based PWM-CSIs switched at 420 Hz.