Practical Prescribed-Time Fuzzy Adaptive Control for PMSMs Under Uncertain Dynamics via Time-Varying Scaling Function

Abstract

To fulfill the dynamic and steady-state performance requirements of permanent magnet synchronous motors (PMSMs) in speed regulation, a practical prescribed-time fuzzy adaptive control approach is investigated. First, a novel continuously differentiable time-varying scaling function is constructed, which avoids the problems of infinite gain and singularity that may arise in the differentiation process of traditional scaling functions. Based on the time-varying scaling function, a new prescribed-time stability theorem is developed, which provides a theoretical foundation for stability analysis and controller design. Next, a fuzzy adaptive mechanism is designed to approximate the motor parameter uncertainties. Meanwhile, a disturbance observer is utilized to estimate the external disturbances. Moreover, an input saturation mechanism is introduced to protect the PMSM system. Stability analysis demonstrates that the speed regulation error converges to a neighborhood of the origin within the prescribed time. Finally, experimental results of the PMSMs further demonstrate the effectiveness of the proposed method. Note to Practitioners—The motivation of this work is to provide a solution to practical challenges in the PMSM system by meeting the requirements for convergence time and the need for robustness under complex operating conditions, such as external disturbances and motor parameter uncertainties. Accordingly, this paper proposes a practical prescribed-time fuzzy adaptive control strategy based on a time-varying scaling function, which allows the upper bound of the settling time to be prescribed, achieves stable control over the entire time domain, and enhances robustness under motor parameter uncertainties and external disturbances. Moreover, ensuring the safe and reliable operation of the PMSMs is a critical concern in practical applications. To address this, an input saturation mechanism is implemented to prevent damage. The effectiveness of the proposed method has been validated on an experimental platform for the PMSM system.