| Wound resolvers have been widely used in the field of aerospace and military because of their high precision, reliable structure, long life-span and low cost. Around their precision, contactless wound resolvers are studied from parameter design and structure optimization aspects in this thesis, which has practical value to some extent.Wire running method plays a decisive role on the precision of wound resolvers. Firstly, the principle and winding structure of wound resolvers are analyzed. Theoretical deviation is conducted in terms of the principle of the resolvers which have sinusoidal distributed windings in both stators and rotors. The electromagnetic designs of wound resolvers with different structures, such as double layer short pitch winding, concentric sinusoidal windings and chutes, are carried out and simulated using FEM(Finite Element Method) software. Then harmonic distortion rate of output signal are analyzed under several different structures. The design method of single pole pair resolvers is given, which can guarantee their precision as well as improving winding utilization ratio.A resolver’s structure decides its internal magnetic flux leakage condition. For resolvers with small length-diameter ratios, magnetic flux leakage ratio is always greater. The combination of field method and road method is applied to analyze and calculate the inductance and end winding magnetic flux leakage of the designed resolver. Besides, Three-dimensional model that is mainly used to analyze the slot and end winding magnetic flux leakage is built in FEM software. In addition, research about tooth/slot number combination and structure optimization of single pole pair wound resolvers is completed. Different resolvers’ structures are compared for their impacts on output voltage’s amplitude and precision, such as stator slot shapes, air-gap length, relative axial length of stator versus rotor, etcetera. A conclusion is drawn that all the aforementioned factors have significant influences on the precision of resolvers’ signal windings.Coupling transformer provides excitation for contactless wound resolver. Aiming at controlling excitation currents and guaranteeing output voltages, circuit analysis and structure design simulation are performed for a coupling transformer with inductosyn as its load. The output characteristic of a coupling transformer with low resistance load is analyzed. The effects on output voltage created by frequency, eddy current loss and air-gap is discussed. Impedance matching problem of coupling transformers is analyzed through simulation. For this kind of transformers, excitation turns on the primary side should not be excessive. Meanwhile, experiment verification of one strategy is conducted, which has ideal result.Although single pole pair resolvers can provide absolute position, their precision is much lower than those of multi-pole pair resolvers. The precisions of multi-pole pair resolvers, which have the same number of pole pairs and different winding designs, are discussed when the number of stator slots and rotor teeth are almost equal. The general relation of resolvers’ precision varying against pole pair numbers is given. The winding suitable for common excitation system is proposed. The outputs of common excitation dual channel wound resolvers and separated excitation dual channel wound resolvers are compared, both of them having the same winding structure, when pole pair number varies. After pole pair number reaching a certain value, the resolvers with common excitation structure have low distortion rate of output signal, and even equal to those of resolvers with separated excitation dual channel structure. |
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