Reduction of a radial electromagnetic oscillating force of an electrical motor 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 reduction methodology of the radial oscillating force that causes the radiation noise from the surface of the motor case by controlling the working currents on IPM moror. 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 the radial force towards the stator and three phase alternating currents is provided firstly, utilizing the radial force 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 radial oscillating force. Finally, the plane electromagnetic field analysis is performed again with the currents including the high order ones and a radial oscillating force reduction of about 20 dB with a torque increase of 2.8% is obtained.