The Research On Induction Motor VVVF Speed Regulation In Electric Traction

In variable-frequency drives of AC motor, it needs to control the relevant variables to ensure three-phase equilibrium of the sinusoidal input current in order to keep the electromagnetic torque of AC motor constant. Judging from the dynamic mathematical model of the induction motor in ABC coordinate system, it's a strong-coupling multi-variable system, which is hard to control. This paper presents the dynamic mathematical model of the induction motor in MT coordinate system. When the direction of the rotor flux is consistent with the M-axis, the control of the stator current is equivalent to the independent control of flux current and torque current. It achieves the performance as good as a DC motor speed control system. In this paper, the study is based on the rotor flux-oriented vector control system.The key of vector control system is to achieve rotor flux orientation accurately. In this paper, the rotor flux observation models are discussed in detail, and the final paper makes a brief discussion on the simulation results of the observation.This paper presents the establishment of the induction motor vector control system. It also presents the designs of the torque current regulator, flux current regulator and the speed regulator.The hardware system consists of control circuit and main circuit, based on DSP chip TMS320F2812. And the design of the control algorithm based on C Language Programming. By established simulation model in Matlab/simulink environment, the induction motor vector control system achieves good steady-state and dynamic performance. The experimental results proof that the designed vector control system is feasible. The vector control system designed in this paper makes a good foundation for the further study of electric traction control system.