Fractional-Order Phase-Corrected Feedforward Repetitive Control With Fast Convergent Augmented Observer for Static-Errorless Current Regulation in PMSM

Traditional driving methods are plagued by numerous disturbances and uncertainties within the motor system, which impact system performance and reliability. To address this challenge, this article proposes a fractional-order phase-corrected feedforward repetitive control form (FPFRC), integrated with a fast convergent augmented observer (FCAO) to enhance current performance. Initially, a repetitive control (RC) based on internal-model feedforward form which leverages the inherent characteristics of the control paradigm is introduced to improve harmonic suppression capabilities and convergence speed. In addition, the concept of fractional-order phase correction is employed to design phase-lag compensation for the internal-mode delay term and phase-lead compensation for the forward channel within proposed FPFRC, thereby materializing resonant frequency robustness and repetitive gain maximization. Subsequently, the proposed FCAO incorporates the measured current integral term as a system augmented variable to decouple the interaction between noise and high observer gain. Finally, the state prediction error can be made to converge to the vicinity of the equilibrium point within a fixed time by modifying a suitably defined nonlinear correction term. Comparative experiments obtained from a PMSM test platform verify the superiorities of proposed strategy.