Research on the Power Factor of an Interior Permanent Magnet Synchronous Machine with Fractional-Slot Concentrated Winding

Taking 12-slot/10-pole interior permanent magnet synchronous machines (IPMSMs) with fractional slot concentrated winding (FSCW) as the study subject, this paper aims to investigate the issue of the power factor and explore the feasible improvement measures. The effect of phase angle and amplitude of stator current on power factor (PF) is studied in detail under the condition of the given rotating speed. Different phase angle of stator current corresponds to different operation state, which is related to control strategies. With increase of inner power factor angle psi(I-s,E-0) ranging from -10 degree to 90 degree, PF increases first and then decreases. PF declines with the amplitude of stator current increasing for the specified control strategies. In addition, the average electromagnetic torque increases with increasing the stator current for different inner power factor angle psi(I-s,E-0)