Electric Motor and Power Electronics NVH Control Strategies for Electric Propulsion Systems of Battery Electric Vehicles

Tonal electric motor whine and high frequency switching noise are among the main NVH challenges of electric propulsion systems for high performance battery electric vehicles. A holistic NVH control strategy is developed and validated by integrating hardware design and advanced motor calibration and PWM controls. A special rotor notch feature is introduced and optimized that significantly reduces electric motor whine up to 20 dB with minimum impact to motor torque or efficiency. Active torque ripple cancellation control is developed to effectively reduce motor winding orders at selected motor torque and speed conditions. A new analytical method is developed that accurately predicts PWM induced noise at both switching frequency and its sidebands. This allows system level switching strategy optimization to balance NVH performance with efficiency and thermal considerations.