Elucidation of the Cause of Positive and Negative Asymmetric Torque Generation of Self-Excited Wound-Field Synchronous Motor Utilizing Space Harmonics

This paper describes the cause of the asymmetric torque at powering and regeneration of self-excited wound-field synchronous motor in which space harmonic flux is utilized to induce the rotor field current instead of the flux by the permanent magnets. The principle of induction motor torque generation which is considered as cause of asymmetrical torque, and the experimental method to identify the cause of the induction motor torque generation is discussed. In addition, Experimental results using prototype motor revealed that the cause of the asymmetric torque at powering and regeneration is the induction motor torque.