Energy Loss Evaluation and Verification of Permanent Magnet Synchronous Motor with Mechanical Winding Changeover Device

This report presents the energy loss evaluation and verification of a Permanent Magnet Synchronous Motor (PMSM) with mechanical winding changeover for electric vehicle traction applications in two standard driving schedules: JC08 and Worldwide Harmonized Light Vehicles Test Cycles (WLTC) modes. We designed a downsized mechanical winding-changeover device with a rated current of a few hundred ampere owing to the multiple contacts and aggregation of movable apparatuses. From the calculated results, the energy loss is observed to be reduced by 6% in the JC08 and 2% in the WLTC modes because of improvement in system efficiency by winding changeover. Actual tests performed on a 5kW PMSM illustrate that the system efficiency improves by up to 5% owing to the reduction of inverter loss and harmonic components of the motor current.