Torque Control Strategy of an IPMSM Considering the Flux Variation of the Permanent Magnet

The variation of the remanence of the Permanent Magnet (PM), according to operating temperature and manufacturing tolerance, especially in the magnetization of the magnet, results in variation of the capability curve of an Interior Permanent Magnet Synchronous Machine (IPMSM). The analysis of the measured torque and estimated flux at several temperatures is described in this paper. Also, a torque control scheme of the IPMSM considering the flux variation of PM, which can be used in the full operation region, is proposed. The scheme is based on measured data and interpolation method, and generates a modified current reference for the precise control of torque regardless of operating temperature and manufacturing tolerance. The validity of the proposed technique is verified by experiments, and the results demonstrate their feasibilities and reasonable performances.