Design and Study of Radial Flux Dual-Rotor Permanent Magnet Synchronous Machine With Modular Stator

In this article, a design method of equal inner and outer flux applicable to radial flux dual-rotor permanent magnet synchronous machine (RFDR-PMSM) with a modular stator is proposed. Based on this design method, the power equation of the RFDR-PMSM with the modular stator is derived, which reveals the theoretical relationship between the main sizes and the power. In order to simplify the winding process of the modular stator, a fractional-slot concentrated winding is selected for RFDR-PMSM with the modular stator. Then, a 24-slots and 20-poles RFDR-PMSM with a modular stator is designed using the proposed design methodology. Through finite element analysis (FEA), it is found that the design RFDR-PMSM with the modular stator has higher power density and efficiency compared with the traditional RFDR-PMSM with a stator yoke. Moreover, a modular stator structure with a pin connection is proposed to solve the problem that the stator loses effective support after removing the stator yoke. Finally, a prototype of the RFDR-PMSM with the modular stator is manufactured. The back electromotive force (EMF), current-torque curve, and the efficiency map up to 10 kW of the RFDR-PMSM with the modular stator are tested, and the correctness of the finite element model and theoretical design is verified by comparing the experimental results with the FEA results.