Optimal torque control of the Interior Permanent Magnet Synchronous Machine

The basic function of any type of electric machine used in automotive powertrain is to propel the automobile in motor mode or to recharge the high-voltage battery in generator mode. The torque control of electric machine in motor and generator modes, using more efficient high-voltage battery, is a goal for automotive industry. The entire control structure must be designed so as to take into account also the limitations of the computer based implementation in an Electronic Control Unit. A good choice for Hybrid Electric Vehicles (HEVs), due to many advantages, is the Interior Permanent Magnet Synchronous Machine (IPMSM). In this paper, a model for a 35 KW IPMSM used by a future HEV is presented. Starting from the developed model a dynamic simulator was implemented in MATLAB/SIMULINK and then, an optimal field oriented control strategy is applied with aims at optimum torque control both in constant torque region and in constant power region, considering the variation of machine parameters. The model was validated against the data provided by Continental Automotive Romania from the system testbench. The simulated results obtained with the proposed control strategy are compared with the ones obtained with the classical PID approach and the results show improved performances.