INSTANTANEOUS SPEED DETECTION WITH PARAMETER-IDENTIFICATION FOR AC SERVO SYSTEMS

Two methods adopting advanced control technology in order to improve the performance of ac servo systems are described in this paper. The first method is the detection of instantaneous speed using an observer. This method provides good response in speed control because it is possible to detect exactly the speed without detection dead time over a wide range of speeds. The second method is the identification of the mechanical inertia time corresponding to motor and load based on the model reference adaptive system (MRAS). This method enables the instantaneous speed detection to be applied to systems in which the mechanical inertia time is unknown. Moreover, it can realize the automatic adjustment of a speed controller using the result of identification. The effectiveness of these methods has been confirmed by experimentation. The experimental system is composed of a digital controller with a digital signal processor (DSP), a PWM inverter, and a permanent magnetic motor.