Digital Speed Control of DC Motor Based on Speed Estimation Method

Abstract

Generally, the speed controller of dc motor is requested to have a quick and accurate response for speed reference and a small speed fluctuation due to the imposed load torque. For this purpose, the drive system of dc motor mounts the speed sensor. However, this speed sensor can not be always implemented because of the limit of the space or the enviromental conditions.
Therefore, from the practical view point, it is desirable to realize a quick speed control of dc motor without speed sensor. This request can be realized by a new method proposed in this paper, which is based on the discrete observer theory. As the motor control system, in which the armature current is sensed, can be treated as an observable system, both the motor speed and imposed load torque can be estimated by the discrete minimum-order observer. In this paper, it is shown that only armature current is a sufficient information for the speed control. This dc motor drive system based on speed estimation method is realized by the microprocessor. Numerical and expermental results are also shown in this paper.