Comparing different configurations for rotary transformer of wound-rotor resolvers

Wound-Rotor resolvers are the oldest and the most widely used resolvers. They are two-phase synchronous generators with high frequency AC excitation. Rotary Transformers (RTs) are used to supply the rotating excitation winding of the resolver. Although RTs offer the benefits of contactless power transmission, harmonic contents of the secondary voltage, phase shift error between the primary and the secondary voltages, and high leakage flux are the main challenges in their usage along with resolvers. Therefore, in this paper, different configurations are examined for RT’s ferromagnetic core to overcome the mentioned problems. All the simulations are done using 3-D time variant finite element method (TVFEM) and the best configuration is chosen for experimental prototyping and measurements. Close agreement between the simulation and the experimental test results approves the performed analysis.