An Improved Saliency-Based Sensorless Drive with Single Current Sensor Using Current Prediction Method for Permanent-Magnet Synchronous Motors

This paper presents the improvement of a low cost saliency-based sensorless drive with a single dc-link current sensor for interior permanent-magnet synchronous machines. The phase currents, reconstructed by the single dc-link current sensor, usually suffer from a significant reconstruction error. This paper analyzes this reconstruction error, especially when applying sensorless drive technique based on a high frequency voltage signal injection. Based on this analysis, an improved current prediction method is proposed to reduce the reconstruction error, where the d-q axes currents are accurately estimated under even zero voltage vector status. Several experimental results under a saliency-based sensorless drive are provided to verify the improvement of the proposed current prediction method.