A New Technique for Analysis of Static Eccentricity in Axial Flux Resolver

Resolvers have been widely used in motion control systems as position sensors. This paper deals with the analysis of Axial Flux Resolvers. Axial flux resolvers are a group of resolvers which can be used in high performance servomechanisms. The accuracy of resolver detected position is affected by errors. Some of these errors are caused by speed fluctuations, permeance ripples, unbalanced voltages, and eccentricity between rotor and stator. Among these errors the static eccentricity (SE) is not corrected electronically. In this paper, the eccentric resolver is modeled analytically based on d-q synchronous rotating coordinate system with different L-d and L-q values and then, the static eccentricity effect based on the developed model is studied. A novel algorithm is proposed for suppressing the eccentricity error. This method is based on analytical model and modern control fundamentals. In a comparison, simulation and experimental results show good agreement. Finally, the effect of air gap length, pole number and excitation voltage on position error of eccentric AFR is investigated, practically.