Loss analysis of space-vector and discontinuous pulse width modulation for an EESM with Dynamic Motor Drive

This study evaluates the impact of generalized discontinuous pulse width modulation (GDPWM) combined with Dynamic Motor Drive (DMD) on the motor and inverter losses of an electrically excited synchronous motor with IGBT inverter for an automotive traction application using simulation. GDPWM, which clamps each phase leg to the positive or negative DC voltage during specified intervals, was found to significantly reduce inverter switching losses with minimal impact to the motor iron losses, even at low modulation index. The reduced inverter switching losses with GDPWM improved vehicle energy consumption by 2.6 percent on the WLTC. DMD, which intermittently operates the motor/inverter in torque pulses at light loads to minimize energy consumption, provided an additional 1.2 percent consumption improvement. The DMD improvement with GDPWM was reduced by approximately one quarter compared to implementation with SVPWM, for which DMD improved energy consumption by 1.6 percent on the WLTC. The reduced DMD benefit with GDPWM was from lower non-DMD switching losses with GDPWM. The combination of GDPWM and DMD resulted in the lowest energy consumption of the strategies considered.