Second Order Radial Force Suppression Method to Superimpose Harmonic Current on Redundant DoF of Double-star PMSM

Motors used in automobiles are required to improve reliability and reduce vibration. As an approach to improve reliability, a double-star permanent magnet synchronous motor (PMSM) with two power converters and two three-phase windings is adopted. The torque ripple is suppressed by the characteristics of the double-star PMSM with winding phase, and proposed control method suppresses 2nd order radial force. Conventional method of weakening the magnetic flux to suppress the 2nd order radial force occupies one of two degrees of freedom for motor control. Proposed method suppresses the radial force by applying harmonic currents to the redundant degrees of freedom generated by adopting the double-star PMSM. The suppression control method was verified by simulation and a 91.7 % suppression effect was confirmed for the 2nd order radial force.