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This paper proposes a design solution for static eccentricity (SE) in axial flux resolvers (AFRs). There are two definitions for static eccentricity in AFRs. The first approach is based on the definition of static eccentricity in conventional radial flux resolvers, wherein the rotor axis does not coincide with the stator bore, but the rotor rotates around its own shaft. In other words, it is different in the angular inclination of the rotor and stator axis. Thus, the air gap of the motor is not uniform. In the second approach, which is more common in axial flux resolvers, when static eccentricity occurs, air gap length remains uniform. Rotor axis remains parallel with the stator axis, although it does not coincide with the stator bore. This means that there is radial misalignment of the rotor and stator axis. In this paper, both definitions are considered, and an innovative design solution is proposed to decrease the effect of both types of static eccentricity in the accuracy of detected position. Threedimensional time stepping finite element analysis (3-D TSFEA) is used to show the success of proposed designs. Finally, both models were evaluated using experimental results.

In this paper, design and optimization of a ladder-type single-sided linear induction motor (Ladder SLIM) for machine tool applications is investigated. High-speed linear induction machines suffer from the end-effect phenomenon, which can reduce the thrust and result in declined output characteristics. Although it is common to consider this phenomenon in high-speed applications, it is essential to take it into account in the design and analysis of low-speed low-air-gap linear machines. In addition, Ladder SLIMs have significant flux density ripples, and using skewed bars for secondary of the machine is a common solution for it. Therefore, providing required equations, an algorithm for designing a Ladder SLIM considering the end-effect phenomenon based on Duncan model is proposed, and effect of several design parameters on the output characteristics are analyzed. In order to find the optimum design parameters, a multiobjective optimization problem considering efficiency, power factor, and braking force due to the end effect is defined. This problem is optimized with two algorithms, interior point and genetic algorithms, and results are compared. Finally, the validity of the obtained solution is verified using a 2-D and 3-D time-stepping finite-element method. Index Terms-End-effect braking force (EEBF), genetic algorithm (GA), interior point algorithm (IPA), ladder-type single-sided linear induction motor (Ladder SLIM), multivariable multiobjective (MVMO) optimization, time-stepping finiteelement method (TSFEM). 0885-8969 . Her research interests include design, optimization, and performance analysis of electrical machines and electromagnetic sensors.

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Variable reluctance (VR) resolvers have some distinguish features over wounded rotor resolvers that make them suitable for industrial applications. Among different types of VR resolvers, sinusoidal-rotor resolvers are preferred due to simple structure and high performance under eccentricities. However, their accuracy is affected by inevitable run-out error. As they work based on sinusoidal variation of coupling area between stator and rotor and under run-out error the coupling area is impaired. Hence, in this study, a new disk shape configuration is proposed for sinusoidal-rotor resolver that is robust against run-out error. Geometrical dimensions are calculated based on optimisations to achieve more accuracy. Three-dimensional time-stepping finite-element method is used to show the preference of the proposed resolver. Finally, prototypes of both conventional and proposed sensors are built and tested. Experimental results verify the success of the proposed structure.

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This study proposes a new design solution for static eccentricity in axial flux induction motors (AFIMs). There are two definitions for static eccentricity in AFIMs. In the first approach, that is, commonly used for double-side machines, the rotor axis does not coincide with the stator bore but rotor rotates around its own shaft. So, the air-gap of motor is not uniform. Usually, in single stator-single rotor arrangement the rotor integrates with rotating parts of mechanical load. So, when static eccentricity occurs, air-gap length remains uniform. Rotor axis remains parallel with stator axis whereas it does not coincide with the stator bore. Based on the authors' knowledge, the latter approach has not been considered before. Therefore in this study a new definition for static eccentricity factor in direct drive is presented. Also, an optimisation is done to decrease the effect of static eccentricity on motor performance. The mathematical model of studied motor in transient and steady state is used based on d-q axis theory. In particular, the proposed model considers the effect of core saturation, and both approaches for modelling static eccentricity. Finally, studied motor is constructed and tested. All parameters of studied motor are calculated based on experimental measurements.

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