Implementation and Validation of a Simplified Dead Time Compensation Scheme for a High-Power Space Vector Controlled SiC Inverter PMSM Drive

Implementing dead time is mandatory to avoid shoot-throughs across the same phase leg switches of a 3-phase half-bridge voltage source inverter. However, it causes distortions in voltage and current waveforms with higher-order harmonics, resulting in torque ripples in permanent magnet synchronous (PMSM) drives. Due to higher switching speed, and sharp dV/dt and dI/dt characteristics, this effect is further pronounced in SiC-based PMSM drives. In this paper, a detailed investigation of the deadtime effect on the output voltage and current waveforms is carried out, and subsequently, the hardware and software implementation of a simplified deadtime compensation scheme based on the current polarity detection method is presented. The implementation involves the integration of a commercially available state-of-the-art high-power SiC intelligent power module and an automotive-grade software and hardware control system to drive a PMSM. LTspice is used for system simulations and a dyno-test bench is used for hardware verification of the deadtime compensation scheme. Results show that the scheme is simple and effective for high-power PMSM drives with considerable improvements in voltage and current waveforms along with a THD reduction of up to 4% in output phase currents for a typical operation.