A novel brushless synchro: Operation principle and experimental results

In synchroes and resolvers, brushes and slip-rings produce a lot of noise in the output signal. Compared to encoders, the application of such position sensors in precision control systems are restricted because of their lower accuracy. In this research, a novel scheme of a brushless synchro is introduced. In this scheme, the secondary windings are mounted on the stator and the stator magnetic flux passes a certain path in the rotor and induces voltage in the secondary windings. The operation principle is clearly described in the paper and by using 2D finite element method the novel synchro is initially designed and analyzed. The stator winding's turns is calculated by a method based on desired harmonic elimination to have a sinusoidal magneto motive force. A prototype has been fabricated and tested. The experimental results are in good agreement with simulations and verify the theoretical concepts.