Improving the model of Permanent Magnet Brushed DC Motor Used in Automotive Industry for Sensorless Speed Estimation

Permanent magnet brushed DC motors are widely used in the automotive industry due to their low cost and simple speed control. Sensorless speed and position estimation are interesting topics for car manufacturers and researchers. Usually, the armature current ripples are used for senseless speed estimation. Therefore, this paper aims to present a model to precisely predict the behavior of this motor, especially in the prediction of armature current ripples. First off, the previous models of DC motor are studied, and then a new test is proposed for measuring armature resistance to increase the accuracy of the model. Besides, the effect of cogging torque was investigated and the model was modified to consider the cogging torque. Finite element analysis used for different studies and verifying the performance of the proposed improved model. Comparison between the results obtained from the proposed model, previous model, and finite element method shows the superiority of the proposed model.