Simultaneous Identification and Adaptive Torque Control of Permanent Magnet Synchronous Machines

Abstract

This paper presents an experimentally verified, Lyapunov-based adaptive control design for permanent magnet synchronous ac machines, which exploits overactuation to achieve parameter identification and torque regulation objectives simultaneously. This is achieved by regulating the states of the system (i.e., the stator currents) to the output error-zeroing manifold, along which they are varied to provide excitation for parameter identification. The proposed control law utilizes a combination of adaptively tuned feedforward and feedback decoupling terms, in addition to proportional feedback, to achieve reference current tracking in the presence of parameter uncertainty. A switching-sigma modification to the adaptive update law is used to ensure robust stability of the closed-loop adaptive system, and excitation for parameter estimation is introduced via the direct-axis current reference input. The resulting controller achieves the simultaneous identification and control objective while providing consistent transient response characteristics with zero steady-state error over a wide range of operating points.