Research On Control Method For Permanent Magnet Synchronous Motor Of Vehicle

With the increasing environmental pollution and the depletion of oil resources, the development of Hybrid Electric Vehicles (HEV) has been paid more and more attention to. Motor and its control is one of key technologies of HEV. Motor control strategy has a direct impact on vehicle's power performance, fuel economy and emissions. Permanent magnet synchronous motors (PMSM) are ideal drive motors with high power factor, high efficiency and high power density. Because of these excellent performances, PMSM become the first choice as HEV drive motors.For the purpose of designing a hybrid electric vehicle motor controller with high performance, high reliability and wide speed range and optimizing control algorithm, this paper has chosen a permanent magnet synchronous motor as a HEV drive motor, improved the control hardware circuit, and used the flux-weakening control strategy based on vector control to control the speed of PMSM. The statistics from experiments shows that the demand for wide speed range has been met. The main work is as below:1) Analyze the whole structure of permanent magnet synchronous motor and the magnetic circuit. Give calculation methods of steady-state performance of permanent magnet synchronous motor, magnetic circuit and parameters.2) Based on the idea of vector control and flux-weakening control, derive conversion formulas between the three coordinates system. Establish the vector control mathematical model of permanent magnet synchronous motor. Set up equations of flux, voltage, motion and torque under the three coordinates system.3) Design the hardware circuit of motor controller. Improve the motor control method on the hardware side. Write software programs. Build up motor control experimental platform.4) Based on the correction of motor position detection and circuit protection functions on the logic side, compare the difference of speed performance between flux-weakening control and no flux-weakening control. Results have shown that the control system has excellent characteristics. Lay the foundation for the system dynamic performance and load testing.