A parameter offline identification method of asynchronous motor of mine inverter

Under the condition of no speed sensor, the speed regulation performance of inverter is closely related to the parameters of asynchronous motor. Most of the existing offline identification methods of asynchronous motor parameters use fast Fourier transform to calculate the current amplitude and phase. There are spectrum leakage and fence effect and it is likely to cause measurement errors. In order to solve the above problems, a parameter offline identification method of asynchronous motor of mine inverter with the asynchronous motor equivalent circuit as the load is proposed. The steady-state response method is used to identify the stator resistance, and the transient response method is used to identify the rotor resistance and leakage inductance. On the basis of this method, the motor model in synchronous rotating coordinate system is established. The current instantaneous values are transformed in rotating coordinate to calculate the current amplitude and phase under the no-load operation condition of constant voltage frequency ratio. Then, the stator-rotor mutual inductance and no-load excitation current are identified, avoiding the spectrum leakage and fence effect. Matlab/Simulink simulation results show that the rotor resistance and leakage inductance parameter identification results are consistent with the given motor model parameters, which verifies the accuracy of the parameter identification method. 380 V/2.2 kW motor parameter identification experimental results show that the voltage signal applied to the motor by the inverter gets the correct current response, which is consistent with the simulation results. Moreover, and the motor parameter identification process has good repeatability and high identification accuracy. The 660 V/90 kW mine inverter core is built, and the identified motor parameters are used in the mine inverter vector control system. The actual test results show that the inverter can start with load and continue to run stably under rated torque. The motor parameter identification results can meet the vector control requirements of the mine inverter.