Loading...

Design and Prototyping of an Axial Flux Resolver for Reduction of Estimated Position Error

Alipour-Sarabi, Ramin | 2020

532 Viewed
  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 53099 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Oraee Mirzamani, Hashem; Nasiri-Gheidari, Zahra
  7. Abstract:
  8. Providing a precise estimation of the position of a moving element is one of the requirements of many position control systems. Resolvers, as electromagnetic sensors, are one of the most suitable options for use in harsh environments with high thermal and mechanical stresses and high contamination. Although resolvers are the most reliable solution for sensitive applications in stressful environments, they are less accurate in normal operating conditions than optical encoders. In this regard, many efforts have been made to reduce the estimated position. Most of the studies have focused on modifying the electronic converter structure, which is responsible for processing the output signals of the resolver. However, the study of mechanical errors, which account for about 50% of common errors in electric machines, has received little attention. Therefore, in this thesis, it has been attempted to reduce the estimated position error by modifying the electromagnetic structure of the resolver. From this standpoint, by studying the effect of physical parameters on the accuracy of axial flux resolvers, the advantage of the number of poles in increasing the accuracy and decreasing the impact of mechanical errors has been confirmed. In order to implement a high-polar resolver with limited dimensions, it is necessary to modify its winding structure. In the second chapter, a two-phase fractional slot concentrated on tooth winding was introduced and then optimized by an optimization algorithm for rotor and stator windings. In this way, indices such as space harmonics, voltage distortion, leakage inductance, fault tolerance, and unbalanced forces are used. The proposed winding arrangement, in addition to increasing accuracy, has also resulted in reduced copper volume. In the following chapter, to increase the resolution of the resolver under static and dynamic eccentricities a new model based on the magnetic equivalent circuit method is presented. The purpose of this modeling is to provide a fast, yet accurate assessment of the performance of the electric machines under different operating conditions. Finally, in the fourth chapter, by the aid of magnetic equivalent circuit and modified winding function methods with the optimal winding arrangement, the effect of static and dynamic eccentricities has been investigated in different conditions. Due to its ease of measurement, the harmonic spectrum of the output voltages was analyzed and evaluated as a reference signal to monitoring and diagnosis the eccentricity, its type, and amount. By studying the indices introduced in this chapter, which are the harmonic contents of the rotor and stator windings, beside the fault detection, a solution based on the modifying the resolver structure has been proposed to increase its fault tolerance in a variety of mechanical errors. In this axial flux structure, which uses two stators and one rotor, the estimated position error has been reduced and the reliability of the system is increased. It should be noted that in addition to the analytical approaches, e.g., the modified winding function method and magnetic equivalent circuit, three-dimensional finite element analysis have been used to evaluate the proposed theories. By prototyping new resolvers, implementing the pre-claimed structures on them, and analyzing the practical results, the aforementioned analytical presentations were approved
  9. Keywords:
  10. Axial Flux Wound Rotor Resolver ; Optimization ; Modified Winding Function Method ; Magnetic Equivalent Circuit (MEC) ; Eccentricity ; Fractional Slot Concentrated Winding

 Digital Object List

 Bookmark

No TOC