This paper describes the development of the drive motor adopted on the newly developed 2013 Model Year (MY) electric vehicle (EV). Based on the 2011MY EV that was specifically designed and engineered for mass-production, the 2013MY powertrain integrates the electric motor, inverter and charging system into one unit in order to achieve downsizing and weight saving, unlike previous 2011 model which had these components segregated.
In general, integration of all components into one unit causes deterioration of the noise and vibration performance of vehicles due to an increase in weight and the number of resonance parts. In order to overcome such problems associated with this integration, each component in the 2013 model has been optimized to reduce noise and vibration resulting in high degree of vehicle quietness.
Since the electric motor is trigger for the noise and vibration in the vehicle, the electromagnetic field circuit of the electric motor has been reformed and redesigned thoroughly. As a result, the noise and vibration performance of the electric motor has been significantly improved.
Furthermore, by optimizing the shape of the electric motor and adopting the new permanent magnet, both improvement of the motor torque performance and downsizing and weight saving of the motor were implemented. This new magnet not only improves the motor torque performance but also significantly reduces the Heavy rare earth (Dysprosium) usage in the electric motor by 40% or more.