Comparative Analysis of Torque Compensation Control Algorithms of Interior Permanent Magnet Machines for Automotive Applications Considering the Effects of Temperature Variation

For automotive applications, accurate torque production and high efficiency of the traction motor are very important. However, the performance of widely used interior permanent magnet (IPM) machines is influenced by temperature variation, and the temperature variation in automotive applications can be profound. In this paper, the state-of-the-art torque compensation control algorithms of IPM machines in the literature are evaluated and compared. The influence of temperature variation on the performance of IPM machines is identified. Based on the compensation principle, existing algorithms have been classified into two different types: torque open-loop and torque closed-loop method. The operating principles, advantages, and disadvantages of each compensation control algorithm have been discussed in detail. It is shown that the interpolation method using lookup tables and the torque closed-loop method with torque estimation and maximum torque per ampere (MTPA) online calculation are the best available candidates in the literature, since they are the only methods which can maintain both torque accuracy and MTPA operation simultaneously during temperature variation. Special opportunities of compensation control algorithms for traction applications are also identified in this paper. With the comprehensive overview provided in this paper, tradeoff and better decisions can be made during the selection of appropriate compensation control algorithms.