ROBUST NONLINEAR SPEED CONTROL OF PM SYNCHRONOUS MOTOR USING ADAPTIVEAND SLIDING MODE CONTROL TECHNIQUES

A DSP-based nonlinear speed control of a permanent magnet synchronous motor (PMSM) which is robust to unknown parameter variations and speed measurement error is presented. The model reference adaptive system ( MRAS) based adaptation mechanisms for the estimation of slow ly varyin g parameters are derived using the Lyapunov stability theory. For the disturbances or quickly varying parameters, a quasilinearised and deco upled model including the influence of parameter variations and speed measurement error on the nonlinear speed control of a PMSM is derived. Based on this model, a boundary layer integral sliding mode controlle r to improve the robustness and performance of a PMSM drive is designe d and compared with the conventional controller. To show the validity of the proposed control scheme, simulations and experimental work are carried out and compared with the conventional control scheme.