Optimal High-Frequency Injection Minimizing High-Frequency Torque Ripple for Sensorless Control of Electric Vehicle IPM Traction Motors

A high-frequency (HF) torque ripple-free sinusoidal HF injection-based sensorless control technique is proposed for electric vehicle (EV) traction motors. The sensorless control is developed for interior permanent magnet (IPM) synchronous machines, which is the most commonly used motor type in EV traction applications. The HF torque ripple minimization is performed by injecting sinusoidal voltage along an optimal injection angle in the estimated rotor-aligned dq frame, which varies with the operating point. The magnetic saturation and cross-saturation that affect the operation of most traction motors are properly taken into account. The effectiveness, stability, and parameter sensitivity of the proposed method have been experimentally verified on a commercial 157 kW IPM traction motor mounted on a test rig.