Research On Flux Estimation Of Direct Torque Control Of PMSM

Energy crisis and environmental pollution is the major problem encountered in the current industrial development. In 2014, most parts of the country have emerged haze phenomenon. The traditional fuel vehicle exhaust is the main contributor to air pollution. The development of little tail gas emission clean energy vehicles will become the trend of the market. Permanent magnet synchronous motor performance has many advantages, such as high power factor, high efficiency, small volume and light weight, so the electric vehicle drive motor is preferred.Direct torque control of AC speed regulation technology is, after a new high performance developed after vector control technology. Therefore, the system has become a hot spot of research of direct torque control of permanent magnet synchronous motor. Based on extensive literature, introduces the structure of permanent magnet synchronous motor,starting from the principle of space vector, the transformation between the three coordinate control system often involved and their derivation, mathematical model in different coordinates of the permanent magnet synchronous motor.This paper on the basis of a detailed analysis of the principle of the traditional direct torque control of permanent magnet synchronous motor, and pushed to the transfer function of the closed-loop speed of permanent magnet synchronous motor. And then in the MATLAB/Simulink environment to build the simulation model, effects of different speed,load torque and parameters of PI system.This paper analyzes some common defects of direct torque control system. Based on the research of methods to improve the control effect. Because the stator resistance and inductance varies with the motor running fever and changes, resulting in inaccurate flux observation. In this paper based on the model reference adaptive stator resistance on-line identification algorithm. According to the theory of model reference adaptive control, push to the adaptive law of the on-line identification of stator of the electron, and verify the feasibility of the algorithm in MATLAB. The simulation results show that the statorresistance parameter is calculated based on the model reference adaptive algorithm is very accurate, and the time is short, can follow the actual resistance value variation. When the stator resistance value changes, the traditional method of flux estimation deviation, and make the system unstable, and join the online identification of flux estimates more accurately,ensure the normal operation of the system.Finally, this paper proposed for further improvement and perfection of the place and theresearch direction in the future.