Proposal of a New Affordable 2-Pole Resolver and Comparing Its Performance With Conventional Wound-Rotor and VR Resolvers

Abstract

In this paper, a new affordable 2-pole resolver is proposed. Since, the commercial 2-pole resolvers are wound rotor (WR) types, at first the performance of a WR resolver is analyzed and shown that despite high accuracy of the sensor, it has a complex structure. The common solution for reducing the complexity of the WR resolvers is using variable reluctance (VR) resolvers. So, the performance of three VR resolvers is discussed. The results show not only the accuracy of the VR resolvers in 2-pole applications is not acceptable but also their accuracy is influenced by imperfection in production and installation. So, a new structure is proposed. The stator of the proposed resolver is exactly the same as WR resolver. While, the complexity of the rotor significantly reduced, even in comparison with VR resolvers. The flux path and the operating principle of the proposed resolver are discussed based on magnetic equivalent circuit. Then, the performance of the proposed resolver is evaluated and compared with traditional resolvers using the 3-D times stepping finite element method. The average of absolute position error and the total harmonic distortion of the voltages’ envelope for the proposed resolver are calculated equal to 0.47° and 1.31%. While those values for the WR resolver are 0.15° and 0.34%, respectively, and 0.48° and 1.31% for the most accurate VR resolver. Finally, the prototype of the proposed resolver is built and tested. Close correlation between the simulation and experimental results validates the success of the design.