Study On Variable-Frequency Asynchronous Motor Speed Control Based On Space Vector Pulse Width Modulation

With the development of electronic technology and all kinds of motor mathematical model and control algorithm is put forward, motor control technology has obtained the unprecedented development, particularly in the microcontroller, digital signal processor applied to the motor speed control, all kinds of high precision, good control characteristic and the motor controller application of high efficiency, greatly improved the performance of induction motor speed control. Variable-frequency motor speed control is one of the highest efficiency and best performance of the motor speed control method, occupies an important position in the whole area of motor speed control. Space Vector Pulse Width Modulation(Space Vector Pulse Width Modulation: SVPWM) variable-frequency asynchronous motor speed control system which joins space vector frequency control in motor speed regulation is a new ac motor speed control technology in recent years, can achieve fairly ideal speed control. In this paper, modeling and simulation for SVPWM variable-frequency asynchronous motor speed control system is studied.This paper first compared the development of asynchronous motor speed control technology at home and abroad and the problem of motor speed control in our country. Based on the analysis of the composition and the basic structure of the asynchronous motor, the linear terms model of the motor are analyzed in detail, the conclude voltage equations, flux linkage equations of three phase asynchronous motor, electromagnetic torque equations, and electrical and mechanical motion equations have been studied in detail, analysis the mathematical model of asynchronous motors in different coordinate system, implements the asynchronous motor, the mathematical model of high order, nonlinear and multivariable coupling into a similar model of the dc motor, so as to realize the independent control of flux and torque of asynchronous motor more conveniently. Third, according to the active power and reactive power of the motor, the principle of reasonable matching iron loss has taken into account, making the operation of the motor to get maximum efficiency. Finally, the basic theory of space vector pulse width modulation control system, expounds the basic thought and the control principle, laid the foundation for calculating SVPWM. Using MATLAB/SIMULINK simulation platform as the simulation tools, Asynchronous motor used in pumping unit as an object, establishes the model of the motor. the space coordinate transform, asynchronous motor SVPWM control of induction motor model is established, static characteristics, dynamic characteristics, disturbance and system parameter changes are simulated to examine the effects of the performance of the system. Simulation results show that SVPWM induction motor speed control has good motor speed control features, which laid a foundation for new research and implementation of ac motor speed control methods.