Research On Off-line Parameter Identification For Induction Motor Based On Three-level Inverter And Vector Control System

With the development of motor speed control technique, vector control is widely applied on industrial and civil field. In the vector control system, system fuction comes under the serious influence if the parameter of control system does not match parameter of induction motor. We must recongnize the parameter of controlled motor befor we control the induction motor.Based on mathematical model of induction motor, this text proposes the off-line method that uses the resources of transducer to recongnize the parameter of the induction motor. This method achieves the goal that detects the parameter automatically.The method on off-line parameter identification for induction motor based on three-level inverter and vector control system recongnize stator resistance and leakage inductance, rotor resistance and leakage inductance, and mutual inductance by direct current test, one-phase test, no-load test without increasing hardware resources. Meanwhile, the text explains simply PWM theory, SVPWM theory and reconstructed voltage. In direct current test, making use of the PWM voltage that transducer produced, we measure stator current and stator voltage in order to calculate stator resistance. In one-phase test, rotor of the induction motor is resting and no electromagnetic torque is produced. At the moment, filed current is very high, and voltage of the induction motor should not be too high. We calculate rotor resistance and leakage inductance by means of measuring stator current and stator voltage as well as power-factor angle. In no-load test, we take V/F measures to calculate mutual inductance, making use of stator current and stator voltage as well as power-factor angle. To guide experiments, the text analyses hardware and software design, including main circuit design, control circuit design and program flow chart. At the same time, the text researches the parameter identification method by MATLAB simulation software, compared with the real parameter of induction motor. The results of these experiments show that this method is viable.Finally, a summary and analysis is made about the theoretical analysis and simulation research, and some outlook of our researching work is summarized as well.