Negative Effect Suppression of Current Measurement Errors in Electric Propulsion System via ILC

Due to the interference of equipment aging, mechanical vibration and other environmental factors, the current sensors in electric propulsion system are prone to gradual measurement problem, such as offset and gain errors. In the case of sensor failure, the motor system will work in a “sub-health state”, and periodic torque disturbance will be introduced into the system. If it is not restrained and compensated, the speed performance of permanent magnet synchronous motor (PMSM) will be affected. In order to suppress periodic fluctuation, an iterative learning control (ILC) algorithm with forgetting factor is paralleled on the basis of the traditional speed PI controller. The traditional PI controller is used to ensure the performance of the electric propulsion system, and the ILC algorithm is used to suppress the amplitude of periodic fluctuations. From the simulation results, the proposed algorithm reduces the amplitude of periodic fluctuations by more than half.