High current switching capabilities of a 3000 V SiC thyristor for fast turn-on applications

Abstract

High voltage, pulse power Silicon Carbide (SiC) thyristors have been under development at GE Global Research Center for the past decade. Previous tests of these relatively mature devices have shown that they can reliably hold off high voltages (> 3 kV) at extremely low leakage currents (nanoamps), and carry high pulse currents (> 1.5 kA) on microseconds timescales, while surviving millions of cycles at a 1Hz repetition rate. To evaluate the performance of these devices on faster time scales and higher power densities, Transient Plasma Systems, Inc. (TPS) conducted brass-board testing to evaluate the hard-switching capabilities of these devices on sub-μs timescales. These tests were designed to baseline dv/dt, di/dt, instantaneous power density, and switching efficiency of the SiC device and compare that against current state-of-the-art Silicon (Si) devices. Compared to a commercially available Si thyristor with a comparable specified current rating, the SiC thyristor turned on seven times faster and was more than 200% more efficient. The high voltage, high peak current, high di/dt, and low losses of these devices makes them an attractive, near-term solution for compact pulsed power systems, which frequently rely on arrays of series/parallel stacked IGBTs or MOSFETs that operate at significantly lower power densities.