Analytical approach of current deformation based on the influence of motor space harmonics in a closed-loop of Field Oriented Control

The reason for the stator current deformation of a Permanent Magnet Synchronous Motor (PMSM) can be categorized into 3 groups: the time harmonics from the voltage power supply, the space harmonics from the non-sinusoidal coil distribution and the nonlinearity of the stator inductance. The classic Field Oriented Control (FOC) system has control over the 1st order, assuming the three phase currents are symmetrical and sinusoidal and the existence of the current harmonic components are ignored. In this paper, the impact of motor space harmonics on the current ripple due to the closed-loop FOC control is analyzed by using system transfer function and Bode diagram.