This work aims to lower the traction drive losses in passenger electric vehicles by utilizing the new voltage modulation strategy called ‘Partial Load Triangular Current Mode’ (PL-TCM). Losses are reduced in the low & partial load regions by exciting the machine terminal with near sinusoidal voltages, mitigating the machine PWM harmonic losses. The PL-TCM comprises of a ‘disconnectable’ AC filter and operates under TCM modulation for low & partial loads but SVPWM in higher loads, avoiding any current overrating of inverter and TCM filter. The current work analyses further the PL-TCM modulation strategy, its challenges and proposes modifications by injecting an optimal common mode voltage waveform (AC & DC-bias) based on the load operating point. For a 300 kW, 800 V synchronous machine drive system it is expected to save up to 25% drive losses (5% total consumption) in the WLTP cycle compared to a 10 kHz SVPWM operation. Experimental validations are made with an inverter-filter system with a custom designed TCM inductor.
