A COMPARATIVE-STUDY OF A LUENBERGER OBSERVER AND ADAPTIVE OBSERVER-BASED VARIABLE STRUCTURE SPEED CONTROL-SYSTEM USING A SELF-CONTROLLED SYNCHRONOUS MOTOR

This paper presents an analysis of the state observer-based robust speed control of a self-controlled synchronous motor (SCSM). A variable structure control (VSC) technique is utilized to achieve robust (parameter-insensitive) characteristics. The speed and acceleration signals required for the implementation of the variable structure speed control (VSSC) are dynamically estimated with stale observers. Two kinds of observers—the Luenberger full-order observer and an adaptive observer— are explored in this paper. The results obtained illustrate that Luenberger observers do not estimate the system states accurately when the system parameters vary. This inaccuracy in the state estimation results in a deteriorated performance of the VSSC. Therefore, the possibility of using an adaptive state observer (ASO) is investigated. As expected, the ASO estimates the system parameters and the system states simultaneously, thus making VSSC possible. The design methods and the simulation results presented demonstrate the potential of the proposed scheme. © 1990 IEEE