Challenges of Finite Element Analysis of Resolvers

Nowadays, position sensors are increasingly used in many applications. One of the most commonly used sensors are resolvers. There are different types of resolvers including wound rotor resolvers, variable air-gap length variable reluctance resolvers, and sinusoidal rotor variable reluctance resolvers. Regardless of the resolvers' configurations, including linear, cylindrical and disk type, finite element analysis (FEA) is inseparable part of design and the performance evaluation of these magnetic sensors. The scope of this study is to discuss challenges in the FEA of resolvers. The influence of mesh quality, time steps, stop time, excitation methods including voltage source and current source and signal processing methods are investigated in detail. Then, a key question in analysis of resolvers is answered. The question is Is total harmonic distortion of induced voltages' envelopes a suitable criterion for the performance evaluation of resolvers? Finally, four prototypes of different types of resolvers are used for experimental tests. Good agreements are obtained between simulation and test results indicating the accuracy of following discussions.