AC Variable Frequency Speed-adjusting System Of Permanent Magnet Synchronous Motor For Hybrid Electric Vehicle (HEV)

This paper reports a series of research and development work on the vector control of Permanent Magnet Synchronous Motor (PMSM) with the aim of its application in the Hybrid electric vehicle (HEV) drive system. The control system combines the electrical motor theories with the modern power electronics techniques, sensor techniques, microprocessor techniques and advanced control theories. As the representative of modern electrical motors, permanent magnet synchronous motor(PMSM) is ideal for advanced Hybrid electric vehicle (HEV) drive systems for its potentials of high efficiency, high torque to current ratio, and low inertia. Thus, permanent magnet synchronous motor is widely regarded in Hybrid electric vehicle (HEV) control field.The digital signal processor of Freescale Semiconductor, 56F8346,is used as the controller in the study. The mainstructures of the software and hardware parts of the control system are introduced. Principles and realization of the main functional blocks of these two parts are illuminated. On the hardware of the system, parts of control circuit and the design and debugging of peripheral circuits are discussed thoroughly. Based o n the hardware circuit, the software is programmed with C language. Dual close loop vector control with feedback of speed and current are realized. The flow charts of main program and PWM interrupt service routines are given. The important control strategies of vector control PMSM such as current sensing and scaling, speed sensing and scaling, bettor co-ordinate trans- formation, generation of sine and cosine, PI regulators, SVPWM vector modulation and so on are all accomplished in the PWM interrupt service routines. In order to unite all the variables in the program, scaling is used.We used RS-232 to communicate with the PC and developed the control and display software by the LabWindows/CVI, it controlled the PMSM very easily anddisplayed the data that we needed.Finally, the experimental results validated and deepened the Conclusions drawn from theoretical research. The results fully approved the usability and reliability for the system.