Design and Analysis of a Novel 2-Phase 4/3 FSPMM with Chamfering and Flange Rotor Poles

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I. IntroductionStator-permanent magnet (PM) electrical machines are potential for developing as high-speed (HS) electrical machines, due to their advantages of high torque density and robust rotor structure. As one of the most promising stator-PM machines, flux-switching permanent magnet machine (FSPMM) has comparable torque density with the rotor-PM machines and easy thermal dissipation. However, the high fundamental frequency of conventional FSPMM is inevitable, making it difficult to be driven by the power electronics device. In this paper, a novel dual-step 2-phase 4/3 FSPMM is proposed and analyzed. Compared with the traditional FSPMM with the odd number of rotor poles, the proposed structure has good flux linkage waveform, non-UMF and high torque density.II. Design and Performance of the Proposed 4/3 FSPM MachineFig. 1(a) shows the structure of the novel dual-step 4/3 FSPM machine. With using this structure, it can achieve the least number of rotor poles. The PMs have the same magnetization direction, whereas the winding directions are inverse, as shown in Fig. 1(b) and (c). The two set of windings can be connected in series, therefore it is convenient to drive the machine. The rear rotor is offset by 60° mechanically with respect to the corresponding front rotor. An appropriate gap distance between two stators is necessary to accommodate the end of inverse windings and avoid excessive magnet flux leakage. The flange and chamfering rotor is designed to reduce the cogging torque, as shown in Fig.2 (a). The performance of the novel 4/3 FSPM is obtained by using the finite element method and the parameters optimization method. Fig. 2(b) shows that the UMF of the proposed machine. It can be seen that the UMF of the proposed machine is relatively small. The peak-to-peak value of the cogging torque which varies with width of rotor flange is drawn in Fig.2 (c). The designed machine can obtain minimum cogging torque of 360.71 mNm.  Design and Analysis of a Novel 2-Phase 4  3 FSPMM with Chamfering and Flange Rotor Poles