Interior permanent magnet synchronous motor control for electric vehicle using look-up table

This paper proposes a look-up table based maximum torque control of interior permanent magnet synchronous motor (IPMSM) for traction of electric vehicles (EV). Maximum torque control is preferable for traction requirement of EV due to requirements of high torque ability in lower speed and wide-adjustable operation range. In constant torque region (below rating speed), Maximum Torque per Ampere (MTPA) can achieve perfect performance, while in field-weaking region (over rating speed), the torque control usually is not satisfactory. The main problem is that on-line calculation of current commands is too complex and time-consuming in real control system. We solved the problem through construction of look-up table for d-axis current off-line, and on-line calculation of q-axis current using torque equation. It can not only permit the maximum torque control performance but also easy for micro-controller to implement. Finally, simulation and experimental system were constructed to verify the proposed method, and results have been found in good agreement with theoretic analysis.