Decoupled current control with novel anti-windup for PMSM drives

This paper proposes a new current controller with modified decoupling and anti-windup schemes for a permanent magnet synchronous motor (PMSM) drive. In designing the controller, an improved voltage model, which is different from existing models in that it reflects all the nonlinear characteristics of the motor, is considered. In an actual PMSM, unintentional distortion occurs in inductance and flux due to magnetic saturation and structural asymmetry. In this paper, the effects of such distortion on voltage ripple are analyzed and the effect of voltage distortion on current control is analyzed in detail. Based on the voltage model, a decoupling controller is developed to effectively separate the d-q current regulators. The controller produces compensation voltages using the current error of the other axis. In addition, an anti-windup controller is designed that takes into account not only the integrator output in PI controllers but also the integrator output in decoupling controllers. The proposed current controller aimed at compensating all nonlinearities of PMSM enables high-performance operation of the motor. The feasibility of the proposed current control scheme is verified by experimental results.