| Currently, politic guidence, technic developments and the environmental protecting requirements are providing much more convenience and propulsion for the development of electric vehicle. It is the best time for automotive industry to catch this chance which would not only make benefit to the growth of new technologies and new markets, but also help to improve the development and the living environment of human. Motor controlling, considered as one of the key technologies in electric vehicle developing, of permanent magnet synchronous motor(PMSM) based on vector control technology has been developed since 1970s and put into practice in many cases since then. However, vectrol control usually fails to meet its theoretical target for the difficulty of rotor flux detecting, the instability of motor parameter values and complexity of algorithm computing in vectol transforming. The technology of deirect torque control technology, which is concise, responsive and more reliable, has been developed later in 1980s with much study to be carried out for practice utilizing. In the introduction, the thesis gave a survey of the development about electric vehicle and electric drive systems in both China and abroad. Then a discussion about the the background and significance of study on motor control technology of permanent magnet synchronous motor based on direct torque control(DTC) technology would be carried out. And a short description on related technologies and products, such as power electronics, would be introduced at aim of developing a high-permance motor controller.To primize the the application of direct torque control technology, the mathematical model of PMSM was derived from its physical structure. Based on the theory model, the direct torque control strategy was studied and put into practice with a theory frame given in detail. The major flaw limiting the extensive use of DTC on PMSM is torque ripple. To reduce the torque ripple, the DTC controlling system was designed using SVPWM technology, developed from vector control, to modulate the stator flux correctly and control the output torque smoothly. Based on the mathematical model of PMSM and two types of DTC control technology, the study also built up two control frames individually for comparing.Considering both the requirements of electric vehicle exploring and the model of DTC control tehnology for PMSM, a motor control system, with both the hardware and software, was designed in the study. The hardware developing mainly includes designing of control circuit, driver circuit, signal sampling circuit, communication interface circuit and the protecting circuit. To fulfil the debugging and running of the controlling theroy on the physic platform, motor controlling software was compiled. The softare was designed modularly with the peripheral initializating in the main function, while the main algorithm which execute the theory model of the direct torque control for PMSM in the interrupt processing algorithm. In considering the harsh environment of vehicle running, many measures was carried out in both the hardware and software designing to improve the capability of antijamming and EMC performance of the controller.Finally, the simulating model, a tool to improve the software and hardware designing within a shorter exploring period, was set up to verify the theory of direct torque control for permanent magnet synchronous motor and compare performances of two different types of DTC technologies. Basic theory and transformation of vectors were all carried out in individual modules. Analysis and comperations are given according to the simulation results.
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