Research On Vector Control System Of Induction Motor Based On Three-Level Inverter

In recent years, with the development of power electronic technology, large scale integrated circuit and computer control technology, coupled with the application of modern control theory, ac variable speed has been widely used in various industrial fields, and become the main direction of electric drive control field. Especially, vector control can make the torque and flux decoupling so that induction motor can achieve similar dynamic effects of DC motor. Therefore, Induction motor vector control is widely applied. Multi-level inverter can achieve high voltage high power, low output voltage harmonic content, small electromagnetic interference, so that it has been widely used in the the high power field. Three-level inverter is a most representative kind of multi-level inverter. Therefore, the research of induction motor rotor field-oriented control system based on three-level inverter has practical significance.Firstly, the relevant theory of multi-level inverte it researchs the topology of diode clamped three-level inverter and the theory of three-level SVPWM algorithm, explains a simplified three-level SVPWM algorithm on the coordinates of60degrees; Secondly,the concept of space vector the thesis researched, derives the model of the induction motor on the two-phase stationary reference frame and two-phase rotating coordinate frame through the transformation of the coordinates, and then it explains the basic theory of the vector control and the algorithm of rotor flux oriented control.The thesis researchs the three-level vector control system based on indirect flux oriented control, designs the current control loop and the speed control loop of the control system. Thirdly, establish the simulation model,the result of the simulation in the Simulink verifies the validity of this algorithm and proves the control system has a very quick dynamic response and high steady state accuracy.At last, it introduces the hardware circuit design of the three-level inverter control system based on TMS320F28335and implements the improved three-level SVPWM algorithm based on the three-level inverter experimental platform; and the result of the experiment proves the improved three-level SVPWM algorithm is correct. It also does some research on vector control system of three-level inverter and the result of the experiments proves that the control system achieves the purpose of decouple control on the flux and torque of the induction motor, and has a quick dynamic response.