Design of Slotted and Slotless AFPM Synchronous Generators and their Performance Comparison Analysis by using FEA Method

Axial-flux permanent magnet machines are popular and widely used for many applications due to their attractive features such as light weight, low noise, high torque, robust and higher efficiency due to lack of field excitation. The main essence of this paper is to perform slotted and slotless axial-flux permanent magnet synchronous generator design based on theoretical sizing equations and then finite element analysis is reinforcement in order to get a more reliable and accuracy machine design. A comparative study of machine design and performances over the same rating but different configurations i.e., slotted and slotless are also discussed. And then, finite-element method (FEM) software was made for the slotted stator and slotless stator (AFPMSG) in order to compare their magnetic flux density and efficiency. The AFPMSG topology considered in this paper is a three-phase double-rotor single-stator topology with 16 pole-pairs, 2kW rated power and 188 rpm rated speed

Coreless and Conventional Axial Flux Permanent Magnet Motors for Solar Cars

Axial flux permanent magnet (AFPM) motors are suitable options for solar-powered vehicles due to their compact structure and high torque density. Furthermore, certain types of AFPM machines may be configured without stator cores, which eliminates associated losses and cogging torque and simplifies the manufacturing and assembly. This paper examines two machine designs for use in the solar-powered vehicle of the challenger class-a single rotor, single stator conventional AFPM machine, and a coreless AFPM machine with multiple stator and rotor disks. The response surface methodology (RSM) is utilized for the systematic comparison of the conventional and coreless topologies and to select the optimum designs among several hundreds of candidates. Designs with minimum losses and mass producing required torque with larger air-gap are favored. The performance of the selected designs has been studied via three-dimensional finite element analysis (FEA). The FEA parametric modeling methodology is validated by measurements on three AFPM machines of the conventional and coreless type

Optimum Design of Axial Flux PM Machines based on Electromagnetic 3D FEA

Axial flux permanent magnet (AFPM) machines have recently attracted significant attention due to several reasons, such as their specific form factor, potentially higher torque density and lower losses, feasibility of increasing the number of poles, and facilitating innovative machine structures for emerging applications. One such machine design, which has promising, high efficiency particularly at higher speeds, is of the coreless AFPM type and has been studied in the dissertation together with more conventional AFPM topologies that employ a ferromagnetic core. A challenge in designing coreless AFPM machines is estimating the eddy current losses. This work proposes a new hybrid analytical and numerical finite element (FE) based method for calculating ac eddy current losses in windings and demonstrates its applicability for axial flux electric machines. The method takes into account 3D field effects in order to achieve accurate results and yet greatly reduce computational efforts. It is also shown that hybrid methods based on 2D FE models, which require semi-empirical correction factors, may over-estimate the eddy current losses. The new 3D FE-based method is advantageous as it employs minimum simplifications and considers the end turns in the eddy current path, the magnetic flux density variation along the effective length of coils, and the field fringing and leakage, which ultimately increases the accuracy of simulations. After exemplifying the practice and benefits of employing a combined design of experiments and response surface methodology for the comparative design of coreless and conventional AFPM machines with cores, an innovative approach is proposed for integrated design, prototyping, and testing efforts. It is shown that extensive sensitivity analysis can be utilized to systematically study the manufacturing tolerances and identify whether the causes for out of specification performance are detectable. The electromagnetic flux path in AFPM machines is substantially 3D and cannot be satisfactorily analyzed through simplified 2D simulations, requiring laborious 3D models for performance prediction. The use of computationally expensive 3D models becomes even more challenging for optimal design studies, in which case, thousands of candidate design evaluations are required, making the conventional approaches impractical. In this dissertation a new two-level surrogate assisted differential evolution multi-objective optimization algorithm (SAMODE) is developed in order to optimally and accurately design the electric machine with a minimum number of expensive 3D design evaluations. The developed surrogate assisted optimization algorithm is used to comparatively and systematically design several AFPM machines. The studies include exploring the effects of pole count on the machine performance and cost limits, and the systematic comparison of optimally designed single-sided and double-sided AFPM machines. For the case studies, the new optimization algorithm reduced the required number of FEA design evaluations from thousands to less than two hundred. The new methods, developed and presented in the dissertation, maybe directly applicable or extended to a wide class of electrical machines and in particular to those of the PM-excited synchronous type. The benefits of the new eddy current loss calculation and of the optimization method are mostly relevant and significant for electrical machines with a rather complicated magnetic flux path, such is the case of axial flux and of transvers flux topologies, which are a main subject of current research in the field worldwide

A general framework for the analysis and design of tubular linear permanent magnet machines

A general framework for the analysis and design of a class of tubular linear permanent magnet machines is described. The open-circuit and armature reaction magnetic field distributions are established analytically in terms of a magnetic vector potential and cylindrical coordinate formulation, and the results are validated extensively by comparison with finite element analyses. The analytical field solutions allow the prediction of the thrust force, the winding emf, and the self- and mutual-winding inductances in closed forms. These facilitate the characterization of tubular machine topologies and provide a basis for comparative studies, design optimization, and machine dynamic modeling. Some practical issues, such as the effects of slotting and fringing, have also been accounted for and validated by measurement

Analysis and design optimization of an improved axially magnetized tubular permanent-magnet machine

This paper describes the analysis and design optimization of an improved axially magnetized tubular permanent-magnet machine. Compared with a conventional axially magnetized tubular machine, it has a higher specific force capability and requires less permanent-magnet material. The magnetic field distribution is established analytically in the cylindrical coordinate system, and the results are validated by finite-element analyses. The analytical field solution allows the analytical prediction of the thrust force and back-electromotive force (emf) in closed forms, which, in turn, facilitates the characterization of a machine, and provides a basis for design optimization and system dynamic modeling

MODELLING OF LINEAR PERMANENT MAGNET MOTOR FOR AIR-VAPOR COMPRESSOR

Power consumption of refrigerator is the top three among the various household appliances. This is because of the lack performance and efficiency of the conventional refrigerator compressor system. This paper describes about the design of linear permanent magnet motor for reciprocating air-vapor compressor application. There are various types of linear motor technologies and topologies for air-vapor compressor that have been discussed, such as, linear induction machine, linear synchronous machine, linear DC machine, and linear permanent magnet machine. The significant designs criteria considered are based on their force capability, higher efficiency, simplicity and cost-effectiveness. Among the linear motor technologies reviewed, a linear permanent magnet machine is the most preferable technologies for the reciprocating air-vapor compressor application due to the high thrust capability and efficiency. There are three categories of the linear permanent magnet, which are, moving-coil, moving-iron, and moving-magnet. This paper is mainly focused on the moving-magnet topologies which considered a tubular permanent magnet, a slotted and a slotless stator, and also a different type of magnet configuration for the reciprocating air-vapor compressor application. The linear permanent magnet topologies have been studied and analyzed in order to obtain the best three designs for the reciprocating air-vapor compressor application. ANSYS software, ANSOFT Maxwell, is used to draw and analyze the proposed designs to get the results of air-gap flux distribution, air-gap flux density and the respective graph. The result for the three designs will be compared discussed in order to choose one best design for air-vapor compressor application. In conclusion, the best design obtained can be apply for air-vapor compressor to increase efficiency, performance and reduce the energy consumption as well

Torque and Power Capabilities of Coreless Axial Flux Machines with Surface PMs and Halbach Array Rotors

This paper investigates employing a Halbach PM rotor array to increase torque and power density within coreless axial flux permanent magnet (AFPM) machines. Analytical and 2/3-dimensional finite element analysis (FEA) methods are developed to study torque and power capabilities within an example double-rotor, single-stator coreless AFPM machine with a PCB stator. Compared to a surface PM topology of the same mass and volume, employing a Halbach array increases torque density by as much as 30% through increased airgap flux density amplitude. Multiple parametric studies are performed to explore methods of increasing torque and power density while employing Halbach arrays combined with enhanced cooling methods and coil transposition to minimize associated losses. A design procedure is also developed that relies on the advantages of coreless AFPM machines controlled by ultra-high-frequency SiC-based drive systems to maximize potential torque gain