Design and Analysis of Modular Permanent Magnet Claw Pole Machines With Hybrid Cores for Electric Vehicles

Abstract

The permanent magnet claw pole machine (PMCPM) is a special transverse flux permanent magnet machine with higher torque density than other electrical machines. However, it is difficult to manufacture using silicon steel sheets since its main magnetic flux path is very complex. To address this deficiency, the soft magnetic composite (SMC) is employed to fabricate its stator core. However, SMC is difficult to make directly into large-size cores; thus, the PMCPM with SMC cores have generally been developed for low-power applications in the past. In this paper, the ring cores made of different materials are analyzed. A modular PMCPM with hybrid cores is proposed, which makes the manufacturing process of large-size PMCPM easier. Meanwhile, three modular PMCPMs with different cores are comprehensively compared to verify the superiority of hybrid cores. Then, setting a double V-shaped interior permanent magnet synchronous machine (DVIPM) widely applied in electric vehicles (EVs) as a reference, the optimal design was carried on the inner rotor claw pole machine (IRCPM) and outer rotor claw pole machine (ORCPM) with different pole numbers, respectively. Meanwhile, an optimization strategy based on prior experience is proposed to reduce optimization time. Finally, a comprehensive comparative analysis was conducted between DVIPM and the designed PMCPMs. Compared to DVIPM, PMCPM is more suitable for working at low speeds and high torques. Especially in the torque range of 200 Nm to 300 Nm, PMCPM has significant advantages. In contrast to PMCPM, DVIPM is more suitable for application in high-speed situations with lower torque. The analysis results have been verified through experiments on a small-size PMCPM with hybrid cores.