Sharif Digital Repository

Compared with flat linear structures, tubular linear machines do not face edge effects, making their performance better than their flat counterparts. In this article, a novel linear variable-reluctance resolver with tubular configuration is proposed. To optimize the design of an electromagnetic structure, modeling methods are used. Thus, in this article, an analytical model for the proposed resolver is presented. This model is based on the magnetic equivalent circuit (MEC) method and is considerably less time-consuming than finite element analysis (FEA), yet provides accurate results. A conformal mapping is employed to compute the permeance of the air-gap. The proposed model is then utilized... 

Resolvers have robust performance in harsh environments due to their electromagnetic structure. Among different types of resolvers, variable reluctance (VR) ones suggest higher reliability, simpler configuration, and lower cost. The same features are available for their linear counterparts. Since the application of linear machines is increasing, low-cost, high-precision linear position sensors attract more attentions. However, the accuracy of linear resolvers strongly influenced by longitudinal end effect and the edge effect. The edge effect can be suppressed using tubular configuration and the longitudinal end effect must be considered and suppressed in the design process. On the other... 

Static eccentricity in the resolver, with higher probability and severity occurrence, gradually injects instability into the drive system; thus, its exact location diagnosis is mandatory. Whereas, most existing investigations rely on frequency analysis of signal voltages for resolver fault diagnosis, artificial intelligence (AI) is at the center of attention for electric motors fault diagnosis. Yet, sufficient data collection brings some challenges for AI. Therefore, intrigued by the idea of few-shot learning to overcome the data scarcity challenge, a convolutional neural Siamese network is employed with limited data to diagnose the static eccentricity location under each stator tooth via... 

In this study an analytical model based on solving Maxwell equations in the machine layers is presented for linear resolver (LR). Anisotropy, field harmonics, slot effects, number of slots per pole per phase and the effect of tooth skewing are considered in the model. The proposed method is a design oriented technique that can be used for performance prediction and design optimisation of the LR due to its acceptable accuracy and fast computation time. Two- and three-dimensional time stepping finite element method (FEM) is employed to validate the results of the proposed model. Good correlations between the results obtained by the proposed method and the FEM confirm the superiority of the... 

Using linear position sensors is necessary in linear motion control systems. In this paper the influence of winding's pole pairs on the accuracy of linear resolver is studied. 2-D and 3-D time stepping finite element method (FEM) is used to calculate the performance characteristics of the resolver. The effect of finite mover's length, transverse edge effect and the end windings length are discussed in detail. Then a prototype of the studied resolver along with its experimental test setup is built. Good correlation between simulation and experimental results verified the simulation process. © 2017 IEEE  

Axial flux variable reluctance (AFVR) resolvers have substantial benefits that make them suitable for motion control drives. However, they suffer from insufficient accuracy, especially in high-accuracy applications. Hence, optimizing the AFVR resolver structure is necessary for improving its commercial usage. However, its accurate modelling needs three-dimensional (3-D) time stepping finite element analysis (TSFEA) that is computationally expensive and unsuitable for co-usage with optimization algorithms. The aim of this paper is to establish an accurate, yet computationally fast, model suitable for optimal design of AFVR resolvers. The working of the proposed model is based on magnetic... 

Wound-Rotor (WR) resolvers are the most widely used position sensors in applications with harsh environmental conditions. However, their performance is exposed to failure due to high risk of short circuit (SC) fault. Although the output current of the resolver is negligible, its thin copper wires increases the probability of the short circuit fault. To avoid the propagation of the turn-to turn SC fault to the whole coil and undesirable performance of the motion control drive, it is necessary to diagnose it at the very beginning of its development. Meanwhile, the first step of diagnosing faults is their modeling. Time stepping finite element analysis is the most accurate, but computationally... 

Inverter driven electrical machines need resolver for position estimation and efficient electronic commutations. In this paper, the resolver signals are also used for the purpose of mechanical fault diagnosis. Therefore, a comprehensive procedure based on winding function (WF) method is presented to propose a noninvasive index to identify the mechanical fault's type (static/dynamic eccentricity) and even its percentage. In this regard, once the resolver signals are measured and saved in health condition. Then, during the operation of the motor, calculating the proposed index using the healthy and faulty signals leads to predict the fault type and its percentage. The success of the proposed... 

Linear variable reluctance (LVR) resolvers have substantial benefits that make them suitable for linear motion control drives. The optimal design of LVR resolvers needs an accurate modeling that is usually achieved by a three-dimensional (3-D) time-stepping finite element method (TSFEM). However, the 3-D TSFEM is a very time-consuming method and is unsuitable for cousage with optimization algorithms. So, in this paper an accurate analytical model based on an improved winding function method is proposed. The proposed model is used to calculate the inductances, air-gap flux density, induced voltages, and linear position error. The distinguished feature of the proposed model is the direct usage... 

Position sensors are inseparable part of motion control systems. Linear resolvers (LRs) are electromagnetic position sensors that are suitable for high vibration, polluted environments. The accuracy of their detected position can be affected by different mechanical faults. In this study, variety of possible mechanical faults along with their mathematical index in LRs is introduced. Static eccentricity, dynamic eccentricity, inclined mover and run out error are the presented mechanical faults that are discussed independently and simultaneously. Then, three-dimensional non-linear, time-stepping finite element method is employed to investigate the performance of the studied resolver under... 

Cost, durability and reliability are three critical issues in electrical/hybrid electrical vehicles (EV/HEV). In this regard, resolvers are often used as position and speed sensors in such applications. In this paper design and analysis of a novel multi-turn resolver is discussed to address all the mentioned issues. The proposed resolver has got one stator core and one rotor core. Double sets of signal windings on the stator and a special excitation winding on the rotor are designed to achieve both absolute and multi-speed operations. Mathematical model of the proposed resolver is verified using time stepping finite element analysis and experimental measurements. © 1967-2012 IEEE  

Multi-turn resolvers are employed in the applications that high reliability; high accuracy and absolute position measurement are required, simultaneously. They are basically consisted of two individual resolvers in a common frame. In this paper a novel sinusoidal air-gap length multi-turn resolver is proposed. The rotor shape and the winding configuration are designed to achieve single-speed and multi-speed operations using a single rotor and a single stator core. Furthermore, some constraints are laid down and discussed in such a way that the performance of two resolvers has no interference with each other. All the mathematical calculations are validated using time stepping finite element... 

Resolver, as an electromagnetic sensor, is widely used in different industrial applications such as servo motor feedback applications because of its reliable performance in the presence of undesired external factors in a harsh environment. Among different types of resolvers, variable reluctance (VR) resolvers draw attention due to their robust structure with a winding-less solid rotor and low-cost manufacturing. In this article, analytical modeling based on the magnetic equivalent circuit (MEC) is employed to investigate the output signals of the proposed toroidal winding arrangements for VR resolver with a 5-X rotor. Time-stepping finite element analysis (TSFEA) is used for all the... 

In this paper static eccentricity (SE) fault diagnosis in wound rotor (WR) resolver is considered and a new noninvasive index is proposed. Using the proposed index not only leads to SE detection but also, helps to precisely determine the eccentricity level. Furthermore, the location of the fault is determined using two search coils. In this regard, a mathematical model based on the winding function method is proposed. In the proposed model the influence of non-uniform air-gap length on calculating the inductances is considered. Then, time-stepping finite element method (TSFEM) is used for approving the success of the proposed index. Finally, experimental tests are done to validate the... 

In this paper, a new disk type variable reluctance (DTVR) resolver is introduced. The proposed resolver works based on the sinusoidal variation of the coupling area between stator and rotor. An analytical model based on winding function theory is proposed for the performance analysis of the sensor. Then, the influence of stator slot shape, radial and peripheral slot width, pole numbers, and slot skewing and harmonic injection into the rotor couture on the accuracy of the proposed resolver is examined. The 3-D time stepping finite element method is used to show the effect of optimizations. Finally, the prototypes of the two-pole, four-pole, and eight-pole DTVR resolvers are constructed and... 

Resolvers are widely used in high performance motion control of inverter-driven motors. Among different types of resolvers, axial flux wound-rotor (AFWR) resolvers have gained more attention due to their higher stability against static eccentricity. So, in this study the influence of stator and rotor winding arrangements on the accuracy of AFWR resolvers is presented. A single/two phase distributed, constant turn winding is considered for the rotor and the influence of short circuit damper winding of the rotor is investigated. For the stator, constant turn, distributed winding and variable turn, on-tooth winding is examined. Finally, it is shown that using variable turn on-tooth winding for... 

Road speed cameras are usually used in photovoltaic power plants, especially in the areas with limited or no access to grid power. However, there are many areas in Iran where wind power is more accessible than solar energy. So, in this study, a small permanent magnet vernier generator is designed to meet power concussion requirements of traffic enforcement camera. The designed generator is optimized to achieve lower harmonic content of no-load induced voltage and lower cogging torque. In this regard, the effect of geometrical dimensions and the configuration of permanent magnets are investigated using three-dimensional time stepping finite element method. Both no-load and full-load... 

Linear position sensors are essential parts of linear motion control systems. Among different linear sensors, linear resolvers are an appropriate choice for harsh environments. Design optimization of linear resolvers needs an accurate, but computationally fast model for their performance prediction. Slotting effect of the cores and end effect are two important phenomena that must be accurately involved in the model to ensure its reliable results. Therefore, in this paper a semi-analytical model based on subdomain modeling technique is proposed for linear resolvers. Then, according to the developed model, the induced voltages in the signal windings of the resolver are calculated and... 

Multi-speed resolvers are used in the applications that need higher accuracy. However, they suffer from losing absolute position information. To overcome this challenge and improve the reliability of detecting position, using multi-turn resolvers is recommended. The conventional configuration of multi-turn resolver is using two individual resolvers on one shaft and into a common frame. Using such configuration needs special care on setting the distance between two resolvers. In this paper a new structure based on dual side configuration is proposed. The performance of the double sided resolver is analyzed and optimized using an analytical model based on magnetic equivalent circuit (MEC).... 

Winding configuration is a crucial factor that highly affects the accuracy of resolvers. A nonoptimal winding could also make the manufacturing process complicated and costly inefficient. In this article, an approach to determine the optimal winding configuration for the resolvers is proposed. This method is applicable for both wound rotor (WR) and variable reluctance (VR) resolvers, and significantly simplifies the winding configuration of resolvers with different pole pairs and teeth numbers. Based on the proposed approach, the winding configuration of multiturn resolvers, which are generally more complicated than single-turn resolvers, is simplified for WR and VR type resolver with...