A High-accuracy Torque Control Strategy of PMSM for Electric Vehicles

Abstract

The actual torque of PMSM may discrepant from the expected torque due to the non-linear characteristics and inconsistency during mass production of PMSM. Meanwhile, achieving high-precision torque control is vital to the safety performance of electric vehicles. A proposed multi-closed-loop algorithm is introduced in this paper. In order to reduce cost and save space, no torque sensors are used. A look-up table model is established by analyzing the data of the calibration experiments, which realizes the high-precision observation of the torque. Under the control of the voltage and current double closed-loop, the proposed power closed-loop further improves the accuracy. The stability of the whole system is analyzed by small signal model, via which, design instructions of proper PI controller parameters are given out. The strategy is verified through the simulation and experimental results.