A Novel High-Order-Harmonic Winding Design in Hybrid-Excited Reluctance Machine for Electric Vehicle Application

Hybrid-excited reluctance machine (HERM) with both dc field and permanent-magnet (PM) excitations has a robust structure and flexible flux regulation capability, which is an emerging integrated starter-generator (ISG) candidate for electric vehicle application. In order to improve the torque density, a novel high-order-harmonic winding design (HHWD) is proposed. The key is to abandon the traditional winding design (WD) which makes use of fundamental field excitation harmonic to adopt a novel WD which utilizes high-order field excitation harmonic. In this way, the no-load back electromotive force (EMF) can be enhanced by 42.7% and average torque can be improved by 38.3%. In this article, machine configuration and operation principle are illustrated in detail. Using the finite element analysis (FEA), the electromagnetic performance of HERMs with traditional WD and HHWD are compared, which testifies the improvement of HHWD.