A New IPMSM With Hybrid Rotor Structure for Electrical Vehicle With Reduced Magnet Loss

Abstract

Aiming at the problem of excessive eddy current loss of permanent magnets in fractional slot concentrated winding permanent magnet synchronous motors (FSCW-PMSM) at high speed, a new PMSM with hybrid rotor structure for electric vehicles (EV) is proposed in the article, the key is to introduce additional ferrite magnets in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$d$ </tex-math></inline-formula> - and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$q$ </tex-math></inline-formula> -axis magnetic flux paths, respectively. Furthermore, slotting on the rotor surface and genetic algorithm (GA) optimization are adopted to compensate for the side effects caused by the introduction of ferrite magnets and to obtain optimal parameters of the new motor. Compared with the traditional all-Nd-Fe-B structure, the proposed hybrid rotor structure can not only curb the magnet loss at high speed, but also present a cost-effective design approach for interior pemanent magnet synchronous motor (IPMSM) for EV applications with less usage of expensive Nd-Fe-B magnets as well as enhanced reluctance torque capability.