Fused Least Squares Based on Phase-Locked Loop Used for Resolver Demodulation Error Correction

To address the cost and flexibility limitations of hardware Resolver-to-Digital Converters (RDCs), this paper proposes a high-precision software demodulation scheme based on a Phase-Locked Loop (PLL) and Fused Least Squares. Targeting the I/Q signal distortions caused by sensor imperfections, this paper design a step-wise error parameter identification algorithm. This method progressively integrates Algebraic Least Squares (ALS) for rapid initialization, Geometric Least Squares (GLS) for precise bias elimination, and Weighted Least Squares (WGLS) with Huber loss function for robust outlier suppression. Simulation results demonstrate that the proposed scheme effectively corrects signal errors and achieves high-precision rotor position estimation, offering a robust, low-cost alternative to dedicated chips.