Motor Drive with Halbach Permanent Magnet Array for Urban Electric Vehicle Concept

Abstract

Permanent Magnet Synchronous Motor (PMSM) with Halbach array increases the fundamental component of the electromotive force, while decreasing the higher harmonics of the PM flux. This allows motors with lower copper losses and lower iron losses due to the absence of higher harmonics in the stator core. Reduction of the no-load losses is of particular high interest for traction applications where a vehicle runs at a rather constant speed. The Urban Vehicle (UV) concept is a one-seater vehicle with light chassis and solar panels. The solar panels allow substantial reduction of the battery size. In UV running at vehicle speeds in the 30 - 50 km/h range, the PMSM iron losses become one of the main contributors of losses and special attention must be paid to the reduction of no-load losses in the motor. In the paper, a PMSM motor with Halbach rotor is built and tested for one-seater vehicle of 90 kg mass and a 0.6 m2 solar panel. At 30 km/h, the power provided by the 0.9 kg Li-Po battery is 78 W and the power consumed by the PMSM with Halbach array is 47 W. Special attention is given in the paper to the no-load losses in the PMSM with Halbach array.