Sampling Period and Stability Analysis for the Microcomputer-Based Motor Control Systems

This paper investigates the stability and sampling problems in the microcomputer-based motor control systems. When a microcomputer is used to perform the control algorithm and to monitor the motor speed, the sampling rate and the controller parameters must be chosen so that the sampled-data system is stable. In this paper, two typical motor control systems are studied; one is based on frequency comparison, and the other on the use of a phase-locked loop. The result shows that the sampling period has a stable region when the system constants and the controller parameters are given. The paper also reveals the information for determining the measuring time and the controller parameters.