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Compensation Position Error In Variable Reluctance Resolver

Lasjerdi, Hamed | 2023

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 56787 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Nasiri Gheidari, Zahra
  7. Abstract:
  8. Position sensors are an integral part of electric machine control systems. There are different ways to determine the position. The most common methods are using resolvers or optical encoders. Resolver is the recommended in harsh environments where there is wide temperature variation, vibration, and dust. Despite their good features, resolvers face challenges such as eccentricity, short circuit fault, single-phase disconnection, and non-ideal signal voltage. The Resolver chosen in this research is the variable reluctance resolver with variable air gap length. Although this type of resolvers is cheaper than wound rotor resolvers, but its position error is high under electrical and mechanical faults. Therefore, in this research, the improvement of this type of resolvers against faults is investigated In this dissertation, the resolver is modeled with the winding function model under static and dynamic eccentricity and short circuit fault. First, inductances and signal voltage are calculated in each fault, then the harmonics representing each fault are determined. In the next step, two algorithms are presented to compensate the position error under these fault, in first algorithm, compensation is done in one cycle using the DFT method, then in second algorithm compensation is done in a faster time using LSE. In all cases, the position error is reduced more than 94%. In the next step, the influence of the dimensional and winding parameters of the resolver such as the change the number of teeth, poles, and the shape of the air gap on the position error under electrical and mechanical fault is investigated and the optimal case is presented, which reduces the position error more than 80%. In the fifth chapter, methods for compensating the non-ideality of the signal voltage and single-phase fault are provided. The performance of each method in an ideal state and against harmonics, amplitude imbalance, phase shift and dc component is investigated and the best method is selected. Finally, the investigated resolver is prototype and experimental test is done, the results of tests show the correctness of the simulations
  9. Keywords:
  10. Variable Reluctance Resolver ; Static Eccentricity ; Dynamic Eccentricity ; Electrical Faults ; Modified Winding Function Method ; Position Error ; Density Functional Theory (DFT)

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