Fea Estimation and Experimental Validation of Solid Rotor and Magnet Eddy Current Loss in Single-sided Axial Flux Permanent Magnet Machines PDF Download
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Author: Xu Yang
Publisher:
ISBN: 9781303514944
Category : Permanent magnet motors
Languages : en
Pages : 0
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Book Description
The rotor and magnet loss in single-sided axial flux permanent magnet (AFPM) machines with non-overlapped windings is studied in this dissertation. Finite element analysis (FEA) estimations of the loss are carried out using both 2D and 3D modeling. The rotor and magnet losses are determined separately for stator slot passing and MMF space harmonics from currents in the stator. The segregation of loss between the solid rotor plate and the magnet is addressed. The eddy current loss reduction by magnet segmentation is discussed as well. Two prototype 24 slot/22 pole single-sided AFPMs, fabricated with both single layer (SL) and double layer (DL) windings are assembled. Methods of loss segregation are illustrated in order to separate the eddy current loss. Finally, an optimal design approach to axial flux permanent magnet machines is presented.
Author: Xu Yang
Publisher:
ISBN: 9781303514944
Category : Permanent magnet motors
Languages : en
Pages : 0
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Book Description
The rotor and magnet loss in single-sided axial flux permanent magnet (AFPM) machines with non-overlapped windings is studied in this dissertation. Finite element analysis (FEA) estimations of the loss are carried out using both 2D and 3D modeling. The rotor and magnet losses are determined separately for stator slot passing and MMF space harmonics from currents in the stator. The segregation of loss between the solid rotor plate and the magnet is addressed. The eddy current loss reduction by magnet segmentation is discussed as well. Two prototype 24 slot/22 pole single-sided AFPMs, fabricated with both single layer (SL) and double layer (DL) windings are assembled. Methods of loss segregation are illustrated in order to separate the eddy current loss. Finally, an optimal design approach to axial flux permanent magnet machines is presented.
Author: Frédéric Dubas
Publisher: MDPI
ISBN: 3036503986
Category : Technology & Engineering
Languages : en
Pages : 252
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Book Description
This book is a comprehensive set of articles reflecting the latest advances and developments in mathematical modeling and the design of electrical machines for different applications. The main models discussed are based on the: i) Maxwell–Fourier method (i.e., the formal resolution of Maxwell’s equations by using the separation of variables method and the Fourier’s series in 2-D or 3-D with a quasi-Cartesian or polar coordinate system); ii) electrical, thermal and magnetic equivalent circuit; iii) hybrid model. In these different papers, the numerical method and the experimental tests have been used as comparisons or validations.
Author: Kai Wang
Publisher: Springer
ISBN: 981130629X
Category : Technology & Engineering
Languages : en
Pages : 216
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Book Description
This book investigates the utilization of harmonics in the permanent magnet (PM) or rotor shape to improve the torque density of PM brushless AC machines including three-phase inner rotor and outer rotor machines, five-phase machines, dual three-phase machines, linear machines, by means of analytical, finite element analyses, and as well as experimental validation. The torque density can be improved while the torque ripple remains low in PM shaping utilizing the 3rd harmonic. In this book, the analytical expression of output torque is derived for PM machines with rotor shape using the 3rd harmonic, and then the optimal 3rd harmonic for maximizing torque is analytically obtained. The book compares the PM shape in surface-mounted PM (SPM) machines and the rotor lamination shape in interior PM (IPM) machines utilizing the 3rd harmonic, and it becomes clear that their shaping methods and amount of torque improvement are different. In a five-phase PM machine, the 3rd harmonic can be utilized in both the current waveform and PM shapes to further improve the output torque. For the dual three-phase SPM machines without deteriorating the torque more than 30% when the optimal 3rd harmonic into both the current and PM shape are injected. The harmonics in airgap flux density have significant influence on the cogging torque, stator iron flux distribution, and radial force between the rotor and stator. These effects has been investigated as well in this book.
Author: Mohammad Farshadnia
Publisher: Springer
ISBN: 9811087083
Category : Technology & Engineering
Languages : en
Pages : 266
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Book Description
This book focuses on the analytical modeling of fractional-slot concentrated-wound (FSCW) interior permanent magnet (IPM) machines and establishes a basis for their magnetic and electrical analysis. Aiming at the precise modeling of FSCW IPM machines’ magnetic and electrical characteristics, it presents a comprehensive mathematical treatment of the stator magneto-motive force (MMF), the IPM rotor non-homogeneous magnetic saturation, and its airgap flux density. The FSCW stator spatial MMF harmonics are analytically formulated, providing a basis on which a novel heuristic algorithm is then proposed for the design of optimal winding layouts for multiphase FSCW stators with different slot/pole combinations. In turn, the proposed mathematical models for the FSCW stator and the IPM rotor are combined to derive detailed mathematical expressions of its operational inductances, electromagnetic torque, torque ripple and their respective subcomponents, as a function of the machine geometry and design parameters. Lastly, the proposed theories and analytical models are validated using finite element analysis and experimental tests on a prototype FSCW IPM machine.
Author: Ju Hyung Kim
Publisher:
ISBN:
Category :
Languages : en
Pages : 362
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Book Description
This thesis proposes topologies of axial flux-switching permanent magnet (AxFSPM) machines having a 6-slot/4-pole configuration. Different from other high-pole topologies, the proposed topologies achieve the capability of even harmonics elimination taking advantages of a dual structure of AxFSPM machine. The dual structure AxFSPM machine includes a dual-rotor single-stator (DRSS) and a dual-stator single-rotor (DSSR) AxFSPM machines. Other cascaded versions are possible. Significant attention is devoted to developing several alternative approaches to reducing the number of rotor poles. Theory of eliminating even harmonics of the flux linkage is presented introducing a new concept of a stator and a rotor shifting to find the offset angle between stator and rotor pole. Furthermore, this thesis presents technical details of the proposed topologies, including sizing equations of the AxFSPM machine, scalability of the sizing equation, topology comparison, cogging torque elimination methods, manufacturing tolerance issue, demagnetization, and structural dynamics of AxFSPM machines. For the initial design of the proposed topology, sizing equations are derived considering the PM dimension and the magnetic flux. The sizing equations are also verified with finite element analysis (FEA) and prototyping to generalize the scalability of the AxFSPM machine. The characteristics of the proposed topologies are investigated with FEA supported by experimental results. Topologies are compared for dual-structure AxFSPM machines as well as dual-rotor single stator axial flux surface PM (AxSPM) machine. Various rotor tooth shaping methods are proposed and compared using FEA to reduce the cogging torque and ripple torque maintaining average torque. Manufacturing tolerance of AxFSPM machine is considered and investigated to quantify the effect of flaws in the manufacturing process. Demagnetization is investigated to provide an understanding of problems of PMs in the stator. Structure dynamics are also considered understanding the effect of dual-structure in AxFSPM machines. Through proof of concept machine, this thesis proves that the proposed topologies physically can be realized in AxFSPM machine. The proof of concept machine also verifies that dual structure is beneficial to eliminate the even harmonics in 6-slot/4-pole AxFPSM machine.
Author: Emad Roshandel
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
The electric machines (EMs) utilized in the electric vehicles (EVs) and hybrid electric vehicles (HEVs) must operate efficiently over a wide range of torque and speed. Hence, the design procedure of such EMs is involved with the performance parameters estimation over various operating points. Efficiency maps (EffMs) project the maximum efficiency of the machine in the torque-speed envelope as well as the torque-speed capability of EMs. So, the EffMs can be used for prediction of the energy consumption of an EM during operation over a driving cycle. -- The main objective of this thesis is the design of EMs for EVs and HEVs. The thesis starts with a short discussion on the advantageous of EVs and HEVs utilization. The different transmission system components in EVs and HEVs are introduced for better understanding of such vehicles. The different factors affecting the various components of the loss in the electric machines and transmission system of the EMs are described. The literature review highlights the role of EMs efficiency in the propulsion system of EVs and HEVs. -- The EMs operating region and the control techniques for operation in different operating regions is introduced in the third chapter of the thesis. The procedure of the calculation of the EffM is explained. Different calculation methods are discussed, and their strengths and weaknesses are clarified. The experimental procedure of the calculation of EffM for EMs is described and the EffM is obtained experimentally for a sample induction machine (IM). The comparison of different EffM methods, in terms of accuracy and computation time, enables the designer to choose an optimum technique for a certain application. -- A step-by-step design procedure based on the finite element analysis (FEA) is introduced for design of the 100kW IM and interior permanent magnet machine (IPMSM) for a HEV. The design procedure not only considers the electromagnetic validity of the designed machines, but also it covers the thermal aspects during the design. The importance of the optimal selection of the number of poles is studied. The effect of the V-shape angle on the torque ripple and cogging torque of IPMSMs is studied. The role of the number of rotor bars on the torque ripple of IMs is another aspect of the study. The advantageous and disadvantages of the IM and IPMSMs are highlighted based on a comparison of their cost, torque density, and power density. -- The design of 100kW and 200kW axial flux permanent magnet machines (AFPMSMs) is the subject of study in the fifth chapter of the thesis. This chapter designs the AFPMSMs for a HEV with the series propulsion system. Initially a design procedure using 3-D FEA is described and applied to design a 100kW AFPMSM, with optimal operation in the constant torque (CT) region. It is shown that the double stator design in double sided axial flux machines can offer a better performance compared to the double rotor designs. The higher power density of the axial flux machines is highlighted by comparison of the performance parameters with existing axial and radial flux designs. The role of the slot numbers, number of pole effect, torque ripple, THD, slot numbers, solid loss, axial force, stator negative stiffness, rotor eddy current loss, demagnetization, and thermal constraints are discussed and analysed during the design. The kriging technique and multi-objective optimization are employed to find the 100kW design with the optimal performance in the CT region. -- The fifth chapter is continued by the optimal AFPMSM designs with capability of the operation in the constant power region. The axial flux interior PMSM (AFIPMSM), fractional slots topologies, and number of poles are the subjects of the study for improvement of the AFPMSM performance in the field weakening region. It is shown that AFIMPSM suffers from a low power factor and low power density. The rotor eddy current losses are investigated in axial flux PM machines which results in the limitation of the utilization of fractional slot designs to achieve an acceptable field weakening performance. The change of the number of poles is investigated as another alternative for the performance improvement in FW. Finally, the optimal 200kW design with the slot per pole of one and capability of delivery of maximum power up to 4 times of rated speed is obtained through an optimization study. The results demonstrate that the increase of the PM and iron losses is an important limiting factor for using higher number of poles in electric machines especially in higher speeds. -- The lack of availability of a fast and accurate model for performance prediction of the EMs is underlined in chapter six. The subdomain technique is used to develop an accurate model for prediction of the performance parameters of the IMs. The model is further improved by adding the saturation consideration capability using the subdomains magnetic vector potentials. This model is validated using the 2-D FEA, 3-D FEA, and experimental results in this chapter. -- The fast speed and high accuracy of the developed analytical model enables to define an optimization problem over the driving cycle points. In chapter seven, an accurate lumped thermal model is proposed to predict the temperature of the IMs during operation in a driving cycle. An optimization design approach for design of IMs with and without consideration of overload condition is introduced. The optimal designs are compared with each other in terms of the performance parameters, power density, and energy consumption over driving cycle. The effect of the consideration of the overload operation on the weight and energy consumption of IMs is discussed. -- A 4kW axial flux induction machine (AFIM) is designed in a same size as a commercial AFPMSM. The challenges for construction of the AFIM rotor and its manufacturing is discussed. The AFIM is constructed for experimental analysis. The effect of the airgap length on the axial force and stiffness is studied through the 3-D FEA and experimental results. It is shown that the axial stiffness in lower airgaps is high which is a limitation for designing the axial flux machines with small airgaps. The optimum airgap with the minimum stiffness is chosen to redesign the AFIM. The locked rotor test is performed experimentally to extract the equivalent circuit parameters of AFIM and validate the 3-D FEA results. The performance parameters of the proposed AFIM are compared with the commercial AFPMSM. The results show the similar power density of both design and less torque density of the AFIM design in the torque-speed envelope. -- In summary, this thesis investigates different types of electric machines and their design procedure for EVs and HEVs. The main contributions of the thesis are (1) Detailed analysis of different physical phenomena on the loss of the electric machines; (2) Analysis and development of different methods for efficiency map calculation of electric machines; (3) A step-by-step design process for design of induction and permanent magnet radial flux machines; (4) Optimal design of axial flux permanent magnet machines with the capability of acceptable operation in the field weakening region; (5) Introduction of an analytical model for performance parameters prediction of induction machines; (6) Prediction of saturation level of induction machines using subdomain technique; (7) Optimal design of induction machine over driving cycle; (8) Design and construction of axial flux induction machine.
Author: Mehdi Taghizadeh Kakhki
Publisher:
ISBN:
Category :
Languages : en
Pages : 131
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Book Description
In order to respect the constraints for efficiency in an electrical machine, losses should be accurately estimated. In the case of a permanent magnet machine fed by a PWM supply, the high frequency harmonic content of the current (associated with the modulation scheme), may generate additional losses in the machine which the conventional models tend to overlook. Development of new models which may take account of these additional losses will allow us to improve the analysis and design of the electrical machines. In this work various models for the prediction of losses in a permanent magnet machine including the mechanical losses, copper losses and magnetic losses are presented. A new loss expression for taking account of the skin effect in a laminated magnetic material due to high frequency harmonic content of the stator current is developed. Regarding hysteresis losses, an algorithm for the identification of the minor hysteresis cycles is presented. An analytical model for the estimation of the PWM losses in the stator of the permanent magnet machine, and a new method for the direct estimation of eddy current losses in the lamination material by 2D-FE analysis are also developed. The design methodology for the design of a surface mounted permanent magnet machine is briefly described. A prototype machine is designed and realised to measure the losses in a variety of operating conditions and validate the loss models. Various models for magnetic losses are compared in order to find the most appropriate method in the time or frequency domains. The method which offers the best performance is then validated in a wide range of operating conditions. The losses in two PM rotors (with or without magnet segmentation) are compared and the effect of magnet segmentation and the choice of rotor yoke material are investigated by 2D FE analysis. These results are also used to evaluate the performance of an analytical model for the prediction of eddy current losses in the rotor magnets.
Author: Akrem Mohamed Aljehaimi
Publisher:
ISBN:
Category :
Languages : en
Pages : 125
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Book Description
Interior permanent magnet synchronous machines (IPMSMs) with rare-earth magnets are widely used by the electric and hybrid electric vehicle industry due to their high efficiency and high torque density. The drawbacks of the IPMSMs like the fluctuating prices of the rare-earth permanent magnets (PMs), the difficulty in flux weakening, and relatively low efficiency in the high-speed region, triggered the need for alternative electrical machines for traction applications. The variable-flux type IPMSMs, also called memory motors, is a promising technology for electrified transportation applications. These machines make use of low-coercivity magnets such as AlNiCo magnets, which makes them rare-earth PM independent. Moreover, owing to the low-coercivity, the AlNiCo magnets can be demagnetized in the high-speed region. This reduces or eliminates the extra current component needed for flux weakening, which results in lower copper/iron losses and improved machine efficiency. Besides, the variable-flux IPMSMs can provide torque densities comparable to rare-earth IPMSMs in high-torque low-speed regions. Since the magnetization state of AlNiCo magnets can be varied online by a short stator current pulse, and the current needed for a particular magnetization state is machine parameter dependent, it is of a vital importance to the drive system to keep track of the magnet flux during transient and steady-state conditions. Moreover, failing in depicting the actual magnetization state of the magnets means a mismatch between the real value of the magnet flux in the machine and the estimated one in the controller, which directly affects the resultant torque and performance. In addition, the current pulse excitation method for magnetization causes non-uniform variable flux distribution in the air-gap. Therefore, an estimation algorithm of the rotor flux linkage of variable-flux IPMSMs via flux harmonics extraction has been proposed. Compared to the existing methods, this method does not need any voltage or current signal injection into the stator winding. The algorithm was experimentally evaluated for different magnetization states and showed a good performance in tracking the rotor flux linkage variations during transient and steady-state conditions. The operating envelopes of the variable-flux IPMSM were found to be affected by the nonlinearity of the magnet flux with the machine direct axis current. New analytical solutions for the operating point were reached for maximum power and maximum output voltage control for the variable-flux IPMSM taking into consideration this nonlinearity. The experimental measurement performed also support the analytical results. The irreversible demagnetization of the low-coercivity magnets in the high-speed region results in extending the braking time of the variable-flux IPMSMs. A simple yet effective minimal-time braking algorithm is proposed and experimentally validated.
Author: Hanne Jussila
Publisher:
ISBN: 9789522148827
Category : Permanent magnet motors
Languages : en
Pages : 119
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Book Description
Author: Sreeju Sreedharan Nair
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
