Cross Saturation Inductance Analysis of a Permanent Magnet Synchronous Motor
This paper presents the cross saturationeffect on a specially designed spoke type permanent magnet synchronous motor(PMSM) for the sensorless vector control. The cross saturation effect becomesvery important where the sensorless control algorithm is used. Accurate fluxlinkage modeling is required to obtain a satisfactory position estimation andeventually minimum induced torque error. The magnetic saturation is the mostimpacting parameters affecting the position error. Since the Ld and Lqinductance difference is generally less than 5% in the spoke type PMSM, theaccurate estimation of the cross saturation is critical for the sensorlessvector control. In this paper, thedesigned PMSM has the Ld and Lq difference in 15% level even for the overloadcapacity. So it is even possible to operate the motor in the transient modeswith the overload capacity by estimating right cross saturation effect withcertain time limits. The mapping of the inductances and efficiency are obtainedby using Finite element method and presented in the paper. Some experimentalresults are also given such as efficiency and power-speed variation at theconstant torque.
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