Comparison between model based and non-model based sensorless methods of brushed DC motor

Abstract

This paper presents a comparison between sensorless techniques for estimating speed of brushed DC motor. These techniques can be classified into two groups: model based methods, non-model based methods. The model based methods use a dynamic model of DC motor, where a sliding mode observer, pseudo-sliding mode observer and observer with PI controller are presented. The non-model based methods use a ripple component of DC motor current, where the motor speed is estimated by applying a novel approach. This approach uses a discrete bandpass filter with a floating bandwidth to extract information about the motor speed from the measured motor current. The results obtained from the experimental verification indicate that the novel approach estimates the motor speed correctly in a wide range of speeds.