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

With the rapid development of power electronic devices and microprocessors. AC variable frequency and speed regulating system has also made a breakthrough. However, AC variable frequency and speed regulating system’s application in high-power medium voltage is restricted owing to the maximum voltage and current of the power electronic devices. Multi-level topology is proposed to solve this bottleneck, and diode clamped three-level topology has been widely used. This thesis researches on the high performance AC variable frequency speed control system based on this topology.Firstly, the thesis introduces the model of the induction motor on the three-phase stationary reference frame and the concept of space vector, 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. Secondly, it introduces 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; the result of the simulation in the Simulink verifies the validity of this algorithm. Thirdly, the thesis introduces 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, and the result of simulation in the Simulink proves the control system has a very quick dynamic response and high steady state accuracy. In addition, it analyzes the impact of motor parameters on the control system, and the result of the simulation proves the parameter has an effect on the dynamic response and load capacity of the control system.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.