Sensorless position estimation of Permanent-Magnet Synchronous Motors using a saturation model

TL;DR

This paper introduces a novel analysis method for sensorless PMSM position estimation at low speeds, leveraging a saturation model and second-order averaging to improve accuracy and robustness.

Contribution

It presents an original second-order averaging analysis combined with a parametric saturation model for enhanced sensorless position estimation in PMSMs.

Findings

Effective position estimation demonstrated on surface-mounted PMSM

Validated approach on interior magnet PMSM

Improved robustness at low velocities

Abstract

Sensorless control of Permanent-Magnet Synchronous Motors (PMSM) at low velocity remains a challenging task. A now well-established method consists in injecting a high-frequency signal and use the rotor saliency, both geometric and magnetic-saturation induced. This paper proposes a clear and original analysis based on second-order averaging of how to recover the position information from signal injection; this analysis blends well with a general model of magnetic saturation. It also proposes a simple parametric model of the saturated PMSM, based on an energy function which simply encompasses saturation and cross-saturation effects. Experimental results on a surface-mounted PMSM and an interior magnet PMSM illustrate the relevance of the approach.