Analysis and Compensation of Intrinsic Position Error in Resolvers for High-Accuracy Applications

Resolvers are essential components for precise position sensing in demanding industrial and automotive applications. Their accuracy is fundamentally limited by inherent imperfections. A significant challenge in both design and compensation is the difficulty in decoupling the position error originating from the magnetic structure from the velocity-induced error (rotational voltage). This paper proposes a new framework to address this challenge. The key innovations of this work are twofold: first, the introduction of a new analytical metric for quantifying the error caused purely by the magnetic structure, and second, the development of an effective compensation algorithm based on this analysis. We introduce the concept of "Intrinsic Position Error," which is isolated by analyzing induced voltages at the zero-crossing of the excitation current, showing it is a direct function of inductance harmonics. Based on this, a novel compensation algorithm is proposed which utilizes the harmonic characteristics of the error signal for a precise position correction. Finite Element Analysis (FEA) were performed to validate the proposed method. The results demonstrate the algorithm’s effectiveness, showing the average absolute position error is reduced by 92%. Experimental validation was conducted on a fabricated sensor prototype. The results showed a strong correlation with simulations, confirming the feasibility and effectiveness of the proposed compensation algorithm. This research provides a valuable tool for designers to optimize magnetic structures and a practical method for achieving high-accuracy position sensing.