Low-Cost Low-Resolution Sensorless Positioning of DC Motor Drives for Vehicle Auxiliary Applications

Brushed DC (BDC) motor drives are widely used in vehicle auxiliary applications. These motor drives, if the position information is required, are usually equipped with position sensors. Even Hall sensors, which are used as a low-cost solution, including pin connectors and cables, are a significant part of the drive cost. To keep costs at a low level, eliminating position sensors for these applications is very important. In this paper, a simple method for accurate sensorless position control is presented. First, the current slot harmonics are filtered to estimate the incremental motor position. Second, a motor modification is introduced, which provides an index signal for the correction algorithm. Several simulation and experimental tests have been conducted. The tests show the effectiveness of the presented method.