Reduction of an electrical motor torque ripple by superposing a high order current

It is important to reduce the vibrations of an Interior Permanent Magnetic motor that is generally installed in electrical vehicles, fuel cell vehicles, and hybrid electrical vehicles. The purpose of the study here is to build up the torque ripple reduction methodology by controlling the working currents on IPM motor. The distributed winding IPM motor with 48 teeth on the stator and 4 pairs of poles on the rotor is treated. The relating equation between torque and three phase alternating currents is shown firstly, utilizing the torque that results from the Finite Element Analysis of the plane electromagnetic field. Secondly, high order currents are derived from the equation and superposed on the basic currents in order to reduce the torque ripple. Finally, the plane electromagnetic field analysis is performed again with the currents including the high order ones and a torque ripple reduction of more than 25 dB with a torque drop of 2.2% is obtained.