Chengjun Liu

The analysis for new axial variable reluctance resolver with air-gap complementary structure

A new kind of a couple-pole axial variable reluctance resolver is introduced in this paper, which is compact, small in size and has huge anti-interference ability, etc. Being special axial structure, the new type reluctance resolver has strong ability than any other kinds of variable reluctance resolvers. The variable reluctance principle of this new resolver is different from the traditional reluctance resolvers because the reluctance of this resolver is changed by varying the coupling area between the rotor and the stator. 3D FEM time stepping method is used in this article to analyze the character of EMF produced by two signal windings. At the same time, every part of magnetic structure is designed based on the simulation result to minimize errors.

The effects of stator and rotor eccentricities on measurement accuracy of axial flux variable-reluctance resolver with sinusoidal rotor

As position and speed sensor, the axial flux variable-reluctance resolver with sinusoidal rotor(AFVRSR) needs to possess high accuracy of measurement. However, the relative locations of stator and rotor sometimes appear some deviations in practical work. The stator and rotor eccentricities caused by the assembly factors could produce serious electrical error. This paper carries on theoretical analysis and finite element analysis when stator and rotor of AFVRSR are provided with different eccentricities. Zero error, amplitude error and function error were measured under the conditions of different eccentricities, such as radial eccentricity of stator, rotating eccentricity of stator and axial eccentricity. The study on eccentricities of stator and rotor could give some theoretical basis to improve the performance of AFVRSR.

Design Considerations of Tubular Transverse Flux Linear Machines for Electromagnetic Launch Applications

Due to the achievable high force densities, permanent magnet linear machines with transverse flux configurations are gaining increased interest in electromagnetic launch (EML) applications, in which the force density demand is crucial. This paper deals with the design of a tubular transverse flux linear machine (TFLM) targeting EML applications, and the issues pertinent to its topology selection, design optimization, and thermal modeling are discussed. By overall comparison of practical topologies and technologies of the TFLM, a tubular moving-magnet topology with separated flux paths is believed to be more appropriate. Design optimization is then performed to maximize the thrust force under specific volumetric constraints. It is shown that the thrust force is more sensitive to the stator segment length, instead of the magnet thickness. Regarding the overload requirement inherent in EML systems, special focus is given on the thermal characteristics of the TFLM at overload conditions, and it is proved that the machine shows appreciable overload capability. Measurements carried out on a prototype TFLM have validated the predictions.

The decoupling study on the dual-channel radial flux reluctance resolver with common magnetic circuit

In this paper, the structure and basic principle of the dual-channel radial flux reluctance resolver with common magnetic circuit are put forward based on the theoretical derivation of the multi-polar radial flux reluctance resolver. The effectiveness and feasibility of decoupling has been verified by theoretical research and the finite element analysis of magnetic field. The results show that the influence of the accurate machine on the coarse machine reduces gradually as the number of pole pairs of resolver increasing. Meanwhile, it is concluded that the harmonic amplitude of the electromotive force (EMF) of the coarse machine signal windings is affected by the superposition angle of salient poles of the accurate machine and coarse machine. This paper points out the general design rule of this resolver, which lays the theoretical foundation for further study of this resolver.