This paper proposes an improved internal-model-control (IMC)-based proportional-integral (PI) current controller for a permanent magnet synchronous motor (PMSM) drive system to solve the parameter dependence problem. The parameter sensitivity of the conventional IMC-based PI controller is analyzed, which indicates that the parameters mismatch would cause oscillation or overshoot. Therefore, this paper utilizes an uncertainty and disturbance estimator to eliminate the impact of the parameters mismatch disturbance caused by the parameters variation. The proposed controller includes an IMC-based PI controller, which is responsible for tracking, and a disturbance estimator, which deals with other control difficulties. The performance and robustness are easily achieved by separately tuning the only two parameters (the desired closed-loop bandwidth and the estimator bandwidth). The frequency-domain characteristic of the proposed current controller indicates that it can effectively suppress the parameters mismatch disturbance. Simulations and experiments have verified the effectiveness of the proposed method.

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