Improved Torque Density of a Permanent Magnet Brushless AC Motor with Novel Pulse Width Modulation Magnet for Electrified Application

Researchers have recently attached more attention on permanent magnet brushless AC motors for electrified propulsion. Considering the further improvement of torque density, this paper proposes a novel pulse width modulation (PWM) magnet array and quantitatively analyzes the magnetic field with different magnet configurations. It is a good potential for reducing the magnet volume. Based on a slotless motor design which eliminates the influence of additional harmonic sources except for that from magnets, investigations on motor performance with proposed magnet array are made. Also, the improvement of torque density is discussed and verified.