Current Measurement Error Compensation Based on Current Ripple Component Decoupling for PMSM Drives

Current measurement errors (CMEs) including the offset error and scaling error exist in permanent magnet synchronous motor (PMSM) drive systems. It will cause periodic ripples in the dq-axis currents and motor torque/speed. Thus, this article proposes a novel method to decouple and compensate for the CME based on the d-axis current ripple component. In the proposed method, the influence of the closed-loop system is taken into account when separating the CME from the measured current. The bandpass filter (BPF) is employed to extract the desired periodic ripple component in the d-axis current. Decoupling of the CME is achieved through a simple mathematical operation and a low-pass filter (LPF). Compensation is performed through the integrator operation. The proposed method effectively eliminates the dq-axis current ripple and speed ripple caused by the CME. The proposed method has robust performance on motor parameters and can be used during the operation of the motor. The effectiveness and practicability of the proposed CME compensation method is verified using experimental results.