Rotor Design of Ultra-high Speed PM Motor with Self-starting Ability

Due to the fact that traditional ultra-high speed permanent magnet synchronous motor (PMSM) has no self-starting ability, this paper proposes a type of rotor by embedding a hysteresis ring/cylinder in it, and then the PMSM can use the hysteresis torque to start. Three different rotor structures are considered, and their transient starting performances are calculated by 2D finite element (FE) method, respectively. The results show the PMSM equipped with the designed rotors can achieve self-starting. PM torque and hysteresis torque are separated from the total electromagnetic torque, and the influence mechanism of PM on the hysteresis torque is analyzed and summarized.