Design Of Electrical Machines Research Articles

Overview on amorphous alloy electrical machines and their key technologies

Amorphous alloy (AA) is attracting more and more attention in electrical machines due to its excellent low loss characteristics. This paper overviews advances on AA electrical machines over the last 30 years, with particular reference to new and novel topologies and processing techniques of AA electrical machines and their key technologies. These include current states and trends for radial-flux AA electrical machines, axial-flux AA electrical machines, influences of processing techniques on electrical performance of AA iron cores, the characteristics of loss and vibration and noise of AA core and AA machines, optimum design of AA electrical machines, etc. The paper highlights the application prospects of the AA electrical machines.

Electric Machine Design through Investigation of Thermal Performance by Installing Thermocouple Sensors

The aim of this paper is to explore new approaches of monitoring, diagnosis, condition evaluation, and possibility of extending the life of transformers. Research, emphasizing to experimental work, is conducted on a 1.5 KVA single-phase transformer to measure the internal temperature of the primary and secondary winding, using reliable instruments. Special consideration is given to the convenience in the acquisition and management of experimental data, so that the proposed monitoring system can be exploited for all kinds of thermal tests and various loading conditions. The transformer under study is designed and constructed from scratch, according to particular technical specifications. Having completed the transformer construction with the temperature sensors linked in each coil, our aim is to apply various types of loads and record the temperature variation inside the transformer. A process of acquisition and processing of data related to various parameters of transformers is developed so as to predict the behavior and prevent the failure of a transformer.

Global and local meta-models for the robust design of electrical machines

This paper presents an optimization framework for the robust design of electrical machines. During the run of a genetic algorithm, all evaluated solutions are kept in an archive, and are used to build different meta-models for the assessment of robustness. The proposed robust design algorithms are verified using analytical test functions and are shown to be efficient and accurate. They have also been applied to the robust design of a surface mount permanent magnet machine considering manufacturing imprecision and different optimal designs (robust and non-robust) are obtained.

Hardware-in-the-Loop Emulation of Linear Induction Motor Drive for MagLev Application

Linear induction machines are widely used in transportation systems due to their many advantages. Design and prototyping of electric machines are an expensive and time-consuming process; hardware-in-the-loop simulation provides an efficient alternative. In this paper, a field-programmable gate array-based real-time digital emulation of single-sided linear induction motor with the drive system is proposed. Implementation of the model is performed in both fixed-point using Xilinx system generator and floating-point number representations using a handwritten VHSIC Hardware Description Language code. Then, an evaluation in terms of real-time step-size and accuracy as well as hardware resource utilization is provided. The whole design was fully paralleled, which resulted in a considerable reduction of model execution time. The minimum time step of 2.3 and 0.8 $\mu \text{s}$ was achieved for floating-point and fixed-point implementations, respectively. The results of the real-time simulation are verified by the experimental results as well as a 2-D finite-element simulation in JMAG software.

USING OF OBJECT-ORIENTED DESIGN PRINCIPLES IN ELECTRIC MACHINES DEVELOPMENT

Purpose. To develop the theoretical basis of electrical machines object-oriented design, mathematical models and software to improve their design synthesis, analysis and optimization. Methodology. We have applied object-oriented design theory in electric machines optimal design and mathematical modelling of electromagnetic transients and electromagnetic field distribution. We have correlated the simulated results with the experimental data obtained by means of the double-stator screw dryer with an external solid rotor, brushless turbo-generator exciter and induction motor with squirrel cage rotor. Results. We have developed object-oriented design methodology, transient mathematical modelling and electromagnetic field equations templates for cylindrical electrical machines, improved and remade Cartesian product and genetic optimization algorithms. This allows to develop electrical machines classifications models, included not only structure development but also parallel synthesis of mathematical models and design software, to improve electric machines efficiency and technical performance. Originality. For the first time, we have applied a new way of design and modelling of electrical machines, which is based on the basic concepts of the object-oriented analysis. For the first time is suggested to use a single class template for structural and system organization of electrical machines, invariant to their specific variety. Practical value. We have manufactured screw dryer for coil dust drying and mixing based on the performed object-oriented theory. We have developed object-oriented software for design and optimization of induction motor with squirrel cage rotor of AIR series and brushless turbo-generator exciter. The experimental studies have confirmed the adequacy of the developed object-oriented design methodology.

Mass Ionized Particle Optimization Algorithm Applied to Optimal FEA-Based Design of Electric Machine

A finite-element analysis-based optimal design of an electric machine takes considerable time for its objective evaluation and has many local minima. Thus, selecting an appropriate global convergence optimization with fast convergence speed is necessary in the optimal design of an electric machine. In this paper, a novel global search optimization algorithm, mass ionized particle optimization (MIPO), is newly proposed. The MIPO is the population-based algorithm, which reflects the interactive force between the ionized particles. The global convergence and the convergence speed are validated by comparison with the particle swarm optimization, which have already been proved for its global convergence when applied to a well-known Goldstein–Price function as a benchmark function. In addition, the algorithm has been applied to the optimal design of an interior permanent magnet synchronous machine aiming for its torque ripple reduction.

Magnetic Field Analysis in Eccentric Surface-Mounted Permanent-Magnet Motors Using an Improved Conformal Mapping Method

This paper presents an improved conformal mapping (ICM) method for magnetic field analysis in one typical surface-mounted permanent-magnet (SMPM) motor considering the static, dynamic, and mixed rotor eccentricities. The ICM method accurately accounts for the slotting effect, the winding distribution, the armature reaction, the magnetic saturation effect, and the working point variation of PMs throughout their volume. The ICM method is also very rigorous to separate the onload air gap field components. First, the slotless model of an eccentric SMPM motor is mapped to one concentric model using a new form of bilinear conformal mapping, and the field solution is then obtained through applying Hague's solution in the main canonical domain. Second, the slotted air gap magnetic field is obtained through the modulation of air gap magnetic field in the slotless physical domain using the complex relative air gap permeance. The ICM method is also used to investigate the influence of rotor eccentricity on the flux linkage of the stator coils. This developed model is validated through comparing with the corresponding results obtained through finite element method and the frozen permeability method. This method can also be used as a tool for design and optimization of electrical machines.

Topology Optimization Based on Regularized Level-Set Function for Solving 3-D Nonlinear Magnetic Field System With Spatial Symmetric Condition

Topology optimization (TO) is an effective method for producing practical design of electrical machines. TO is conventionally implemented based on the material density; however, this approach can yield a large number of grayscale areas and unfeasible shapes. On the other hand, when the level-set function is applied to the TO of the magnetic field problem, the potential for obtaining a feasible solution improves. This paper implemented a TO method that uses the regularized level-set function to solve the 3-D nonlinear magnetic field problem. Furthermore, a spatial symmetry condition (SSC), which can introduce the mirror and periodic symmetry of the level-set function from the viewpoint of the electromagnetism, is proposed. To achieve symmetry in the electromagnetic field distribution, the validity of the SSC is investigated and confirmed in a 3-D magnetic shielding problem.

Search Region Management Method for Local Search Algorithm Employing Design Optimization of Brushless DC Motor

The optimal design of electric machines requires a significant amount of computation time, since the design is usually performed based on finite-element analysis (FEA) for better accuracy. For this reason, the development of an optimization algorithm is regarded as a prerequisite to reduce the number of objective function call, which is directly related to computation time. The local search algorithm does not guarantee that the global optimum solution can be searched effectively. Therefore, in this paper, we introduce the novel optimization method, search region management (SRM), to improve the efficiency of the local search algorithm. SRM uses a guided random bit generation based on Gray code for the region selection when the local search iterates the optimum search process for a multi-start. In addition, the SRM saves and manages the information of previous searched points to prevent overlapping calculation and to increase the effectiveness of the local search during every iteration process. To clarify the effectiveness of the proposed method for electric machine design, it is applied to the optimal design of brushless dc motor coupled with FEA minimizing torque ripple.

A 2D finite element study on the role of material properties on eddy current losses in soft magnetic composites

The use of soft magnetic composites (SMCs) in electrical engineering applications is growing. SMCs provide an effective alternative to laminated steels because they exhibit a high permeability with low eddy current losses. Losses are a critical feature in the design of electrical machines, and it is necessary to evaluate the role of microstructure and constitutive properties of SMCs during the predesign stage. In this paper we propose a simplified finite element approach to compute eddy current losses in these materials. The computations allow to quantify the role of exciting source and material properties on eddy current losses. This analysis can later be used in the development of homogenization models for SMC.

Multidisciplinary Design Process of a 6-Slot 2-Pole High-Speed Permanent-Magnet Synchronous Machine

High-speed permanent-magnet synchronous machines (HS PMSMs) are a popular topology among modern electrical machines. Suitable applications for such machines are low-power vacuum pumps, compressors, and chillers. This paper describes a systematic design methodology for an HS PMSM using two case studies. The design process for such high-speed (HS) machines is multidisciplinary and highly iterative due to the complex interaction of the many design variables involved. Consequently, no single optimum solution exists, and multiple possible solutions can meet the customer requirements. Practical solutions should be within acceptable thermal limits, should be energy-efficient, and should be rigid enough to withstand the forces exerted during operation. The proposed design flow is divided into steps that are presented in this paper in the form of a flowchart with emphasis on mechanical aspects. Each step represents a task for a thermal, mechanical, or electrical engineer. The features of each step and the prerequisites for moving to the next step are discussed. The described methodology was implemented in the design of two HS PMSMs. The output performance results of the design flow are compared with measured results of the prototypes. The design process described in this paper provides a straightforward procedure for the multidisciplinary design of HS permanent magnet electrical machines.

Optimization of Geometry of Poles of Cylindrical Electrical Machines with Permanent Magnets

The paper presents a method for optimizing the geometry of the selected class slotless electrical machines with permanent magnet poles based on the method of enumeration. The pole is divide into a certain number of concentric annular sectors. For each sector, calculated the optimal design, the superposition of the received magnetic systems for optimum design of the poles of the electric machine. In this example, as a criterion for optimization is selected the average value of the starting torque. These results confirm the usefulness of this method in the design of electrical machines with cylindrical permanent magnets.

Guest editorial - Electric machines in renewable energy applications

The main objective of this special issue is to collect and disseminate publications that highlight recent advances and breakthroughs in the area of renewable energy resources. The use of these resources for production of electricity is increasing rapidly worldwide. As of 2015, a majority of countries have set renewable electricity targets in the 10%–40% range to be achieved by 2020–2030, with a few notable exceptions aiming for 100% generation by renewables. We are experiencing a truly unprecedented transition away from fossil fuels, driven by environmental, energy security, and socio-economic factors.Electric machines can be found in a wide range of renewable energy applications, such as wind turbines, hydropower and hydrokinetic systems, flywheel energy storage devices, and low-power energy harvesting systems. Hence, the design of reliable, efficient, cost-effective, and controllable electric machines is crucial in enabling even higher penetrations of renewable energy systems in the smart grid of the future. In addition, power electronic converter design and control is critical, as they provide essential controllability, flexibility, grid interface, and integration functions.

Novel tubular switched reluctance motor with double excitation windings: Design, modeling, and experiments.

The space utilization of linear switched reluctance machine is relatively low, which unavoidably constrains the improvement of system output performance. The objective of this paper is to propose a novel tubular linear switched reluctance motor with double excitation windings. The employment of double excitation helps to increase the electromagnetic force of the system. Furthermore, the installation of windings on both stator and mover can make the structure more compact and increase the system force density. The design concept and operating principle are presented. Following that, the major structure parameters of the system are determined. Subsequently, electromagnetic force and reluctance are formulated analytically based on equivalent magnetic circuits, and the result is validated with numerical computation. Then, a research prototype is developed, and experiments are conducted on the system output performance. It shows that the proposed design of electric linear machine can achieve higher thrust force compared with conventional linear switched reluctance machines.

Sub-Domain Model of Eddy Current Loss in Windings for Flux-Switching Permanent Magnet Machine under Open-Circuit Condition

This article shows a two-dimensional analysis model for predicting eddy current loss in a winding flux-switching permanent magnet under an open-circuit. The finite-element method is used for electrical machine design; however, this numerical method is always time consuming. Depending on the geometry, the mesh quality of the finite-element method should be high, and thus the finite-element method is more time consuming for special electrical machines. To solve this problem, a sub-domain model using Fourier analysis is improved for a flux-switching permanent magnet machine. It is obtained by solving Poisson and Laplace equations in polar coordinates for each domain, i.e., the magnet, air gap, rotor and stator slots, as well as external region. The model accounts for the influence of interaction between the stator slots and air gap, as well as rotor slots and air gap. Magnetic field distribution, flux linkage, back-electromotive force, cogging torque, and eddy current loss waveforms are derived from the analytical method and verified by finite-element analysis. To the best knowledge of the authors, such an analysis has not been carried out previously.

A Review of Structural and Thermal Analysis of Traction Motors

Traction motors for hybrid electric powertrains have stringent operational requirements including delivering high torque at low speeds and high power at cruising speeds. They require a wide speed range and high efficiency along with high power density and mechanical robustness. Traction motors and their drives are also expected to deliver superior performance throughout the lifetime of the vehicle. Considering the extreme loading conditions, the motors should be designed for very strict thermal requirements. Therefore, all electromagnetic, mechanical, and thermal variables must be thoroughly addressed in motor design. In this review paper, a summary of current structural and thermal simulation methods applicable for traction motors is presented. Prominent design issues along with appropriate analysis methodologies are explained. In addition, brief case studies of electromagnetic, structural, and thermal analysis performed at Fiat Chrysler Automobiles (FCA) US LLC are highlighted. A detailed list of references and an analysis road map are also provided to aid practicing engineers and researchers involved in electric machine design.

An AHP-based approach for design optimization of flux-switching permanent magnet generator for wind turbine applications

Summary Compared with different types of renewable energies, wind energy has the fastest annual growing rate over the last decade. Hence, employing a framework based on numerical algorithms for optimal design of electrical generator, especially adopted for wind power systems, is a great challenge in electrical systems. Recently, for their rigid structure, high torque density and lower mass of the flux-switching permanent magnet (FSPM) generators have attracted much interest because they are capable of supplementing conventional permanent magnet synchronous generators. In this paper, a new analytical hierarchy process (AHP) approach is proposed for a multi-objective optimization of the design of the FSPM generator. To carry out the optimization, trade-offs are considered among more conflicting targets (cost, mass, and some electromagnetic performance). Finite element method numerical results, experimentally validated by means of a prototype, have been used to assess the required data for the optimization. Then the optimal solutions given by the AHP method have been compared with the solutions obtained using different classical optimization methods. The results showed that the AHP approach gives the best solution with respect to the earlier designs and also with respect to other conventional optimization methods, confirming its effectiveness to be used in the optimal design of electrical machines. Copyright © 2015 John Wiley & Sons, Ltd.

Guest Editorial Optimal Design of Electric Machines

The papers in this special section cover the advances in multi-objective design and optimization based on genetic algorithms, surrogate, polynomial regression, and particle swarm optimization techniques. Design of novel trans-rotary magnetic gear, hybrid machines for dc generation, and two degrees of freedom split-stator induction machines highlight new magnetic configurations and their performance evaluations. Multiphysics analysis of magnetothermal and magnetostructural behavior of Switched Reluctance Machine (SRM) and brushless doubly fed machines shed light on analytical and practical aspects of design in electromechanical converters. Finally, control of torque undulation, loss minimization, low speed high torque operation, and advanced digital control of adjustable speed motor drives conclude this unique collection of papers.

Influence of Machine Integration on the Thermal Behavior of a PM Drive for Hybrid Electric Traction

This paper describes a method for fast identification of the thermal behavior of vehicle integrated electric drives to propose a better understanding of electric machine design tailored to driving cycles. A simple, but satisfactorily accurate, calculation method for the estimation of machine losses, which is an input for the analytic thermal network, in the early design stage is introduced. The analytic models, which are verified using measurement data, are used for parameter and case studies for consideration of the thermal environment, with a focus on the gearbox. The first case study analyzes the influence of the gearbox on the thermal behavior of critical machine components. Aiming to use the gearbox lubricant for cooling the winding heads, an improvement of machine performance using an alternative cooling approach, which cools down the end windings, is shown in the second case study.

Determination of the magnetic losses in laminated cores under pulse width modulation voltage supply

In the laminated ferromagnetic cores employed in transformers and electrical machines energy losses occur resulting in a warming effect and efficiency decrease. Normally, manufacturers only provide iron losses data when a sinusoidal voltage supply is applied, but the actual operating characteristics of electrical machines include non-sinusoidal supplies, in particular pulse-width modulation (PWM). This information can be experimentally obtained, but only measuring systems that have function generators with arbitrarily programmable waveforms allow measurements in the presence of higher harmonics. Therefore, having an analytical tool to obtain the most accurate estimation of the magnetic losses is of great interest in addressing the design of electric machines. This paper validates an analytical-expression-based procedure, which delivers results with acceptable accuracy under all operating conditions for the estimation of losses in laminated cores. In addition, it investigates the influence of the modulation amplitude and the switching frequency of the PWM signals in the magnetic losses of soft magnetic materials. For this purpose, non-oriented fully processed electrical steel strips have been measured in a commercial AC permeameter using a single strip tester.