Radial Force Suppression Method Using A Redundant Degrees of Freedom of Double-star PMSM

This paper proposes a vibration suppression method for double-winding PMSM drive with double three-phase inverter to reduce the vibration of electrical power steering motor. Multiplexing the windings to improve reliability increases the control flexibility and adds redundant degrees of freedom compared to general three-phase PMSM. The redundant degrees of freedom are noted and used to reduce radial force that causes vibration of motor. In this paper, the relationship between the radial force that is cause of vibration and the harmonic current is investigated for the purpose of suppressing the vibration generated from the double-star permanent magnet synchronous motor. Applying harmonic currents of additional degrees of freedom on synchronous frames acts on radial forces of variable orders. Experimental validation shows a 74.7 % reduction in 12th order radial acceleration and a 57.3 % reduction in 4th order radial acceleration.