Reduction of Cross Magnetization in Interior Permanent Magnet Synchronous Motors with V-Shape Magnet Configurations by Optimizing Rotor Slits

This paper describes characteristics improvement of interior permanent magnet synchronous motors (IPMSMs) with V-shape magnet configurations by reducing cross magnetization. First, the effect of the cross magnetization in the V-shape IPMSM is investigated by using the finite element analysis with frozen permeability technique. From the observations of the calculated results, a slit in the rotor is proposed to reduce the cross magnetization. After confirming the validity of the FEA by experiments of a prototype motor, the slit shape is determined by automatic shape optimization. It is clarified that the maximum torque of the V-shape IPMSM increases by the optimized rotor slit.