Offline Parameter Identification Strategy of Permanent Magnet Synchronous Motor Considering the Inverter Nonlinearities

For permanent magnet synchronous motor servo system, its performance largely depends on the setting of controller parameters, while the tunning of current loop depends on the accurate motor parameters. For the sensorless control system, the design of observer also needs accurate motor parameters. Therefore, offline parameter identification is particularly important for both controller and observer. However, the inverter nonlinearities will affect the results of the parameter identification. Even though various compensation algorithms have been proposed, they are difficult to be applied in industry. To solve this problem, a three-phase parameter identification strategy is proposed considering the inverter nonlinearities for PMSM servo system. The resistance and inductance of the PMSM are calculated by injecting a series of current steps and a voltage step signal. Compared with the conventional method of parameter identification, the proposed method has the potential to the capability of fault diagnosis. Experimental results show that the studied method can estimate the resistance and inductance parameters accurately.