Simulation Study on Flux Weakening Performance of Dual-Rotor Switched Flux Permanent Magnet Motor

For the requirements of high-speed permanent magnet motors, flux weakening by d-axis current is an effective solution to increase the speed limit, but this approach usually leads to additional losses, which affects the energy efficiency of the motor and shortens its service life. Therefore, a new dual-rotor flux switching permanent magnet motors (DR-FSPM) is proposed in this paper. By controlling the angle between the inner rotor and the outer rotor, the magnetic circuit reluctance is changed to achieve flux weakening by mechanical structure. Firstly, the magnetic flux switching principle of DR-FSPM is analysed. Secondly, based on the dual-rotor flux weakening principle, the influence of geometric parameters on motor performance is discussed through the finite element method analysis. The results show that reasonable design of inner rotor geometric parameters can effectively weaken the permanent magnet flux linkage of motor. By adjusting the angle between the inner and outer rotors, the flux linkage and the induced electromotive force can be adjustable. That achieves the continuous changing from the normal to flux weakening state of the motor, and increases the speed limit of motor.