Research On Permanent Magnet Synchronous Motor Parameter Matching And Control Algorithm For Hybrid Electric Vehicle

Nowadays, as the energy crisis and environmental pollution are worsening, hybridelectric vehicles (HEVs) have attracted more and more attention by the advantages of lowemission and low fuel consumption. Driving motor control system is one of the keytechnologies of HEVs. Based on the analysis of the performance contrast of several typicaldriving motors, the paper selected the interior permanent magnet synchronous motor(IPMSM) as research object.To satisfy the power requirements of a hybrid electric vehicle (HEV), the motor shouldwork with constant torque below base speed and constant power above base speed. Inaddition, its constant power operation range should be wide enough. The goal is to meet theabove output characteristics, enhance the output performances at high motor speed andimprove the stability of the system in field-weakening region. To achieve the goal, thefollowing works have been done: motor noumenon parameters matching, optimizing andimproving the control arithmetic of the system, modeling and simulation etc.1. Understanding the motor theory and establishing a motor model is the priority issuefor motor control. Fistly, motor mathematical models are established in different coordinateframes. Based on the mathematical model in the dq frame, the simulation model isestablished in the environment of Matlab/Simulink.2. The influence factors on the output performance of motor are analyzed and thecontrol strategies of inverter and stator current are gained. The influence of thecharacteristic parameters (the saliency ratio and field-weakening ratio) is analyzed on theexternal characteristic of motor with the constraint of control strategies. Based on theseanalyses, the feasible regions of saliency ratio and field-weakening ratio are obtained, andthe formulas of PMSM noumenon parameters are derived. Finally, a group of PMSM noumenon parameters are calculated for the research car.3. The on-board batteries provide electric power for the driving motor; it can beapproximately regarded as a voltage source, so the voltage inverter is adopted. Thefundamental of the space vector pulse width modulation (SVPWM) is elaborated in detailand this method has an inherent defect, that is, the phase lag of voltage. So this paperproposed the voltage compensation method and verifies the effectiveness of this method.Then the over-modulation strategy of inverter is designed to improve the output function ofcontrol system according to the theory that the voltage amplitude values are equal.4. The field-weakening is an unavoidable problem for control system of the drivingmotor. The ideal current trajectory is obtained, according to the theory of magnetic-fieldcontrol, when the motor operates in the field-weakening region. This paper learnt theadvantages of the feedforward field-weakening and the feedback field-weakening. And thenthe feedforward-feedback field-weakening control algorithm based on the over-modulationstrategy is designed to improve the output performance of the motor and expand the workarea of the motor.