Analytical and numerical study of a new kind of PM brushless motor with trapezoidal EMF for low cost and low inertia applications

This paper deals with the design of a new kind of PM brushless machine for low cost and low inertia applications. The proposed solution is based on the use of rare earth bonded magnet of prismatic shape. This unconventional solution allows to obtain trapezoidal waveforms which can be very interesting in a simple 120 degrees two phases energized current control strategy. These structures are studied and compared with conventional ones using an analytical method based on magnetic charge theory. This analytical method is validated by finite difference calculation. The study shows that these very original solutions can be very advantageous in terms of performance, weight and inertia