Current Measurement Offset Error Compensation for IFOC Induction Motor Drives

In vector control, the accuracy of the current measurement is crucial for ensuring good control performance. However, current measurement offset error is caused by various reasons in the current sensors, the op-amplifiers, and the A/D conversion circuits, such as thermal drift and nonlinearity. The measurement offset error results in undesired current ripples, which deteriorates the speed and torque control performance of the vector-controlled drive systems. This paper proposes the PI-type observer-based current offset error compensation method for the induction motor (IM). The proposed PI-type observer can estimate the DC offset error during the motor operation, which is designed in the stationary reference frame. This study analyzes the effect of the parameter mismatch and confirms the robustness of the parameter mismatch. Simulation and experimental results are provided to verify the performance of the current measurement offset error compensation method.