Transverse flux machines with distributed windings for in-wheel applications (original) (raw)
Comparison study of permanent magnet transverse flux motors (PMTFMs) for in-wheel applications
2009 International Conference on Power Electronics and Drive Systems (PEDS), 2009
This paper investigates the existing structures of transverse flux machines (TFMs) that can be constructed as an outer rotor in-wheel motor which is suitable for low speed applications. As the main characteristic of TFM is providing the best torque density at low speeds, it would be a suitable choice and having a great future for low speed mobile platforms. Different structures of TFM are redesigned as outer rotor motors with the same diameter, axial length and pole number and they undergo a comparison study through the use of three dimensional (3D) finite element method (FEM). The simulations have been done via Flux3D software from Cedrat. An analytical study of the TFMs is done in terms of highest torque production capability and design optimisation.
A Novel Transverse Flux Machine for Vehicle Traction Applications
novel transverse flux machine topology for electric vehicle traction applications using ferrite magnets is presented in this paper. The proposed transverse flux topology utilizes novel magnet arrangements in the rotor that are similar to the Halbach array to boost flux linkage; on the stator side, cores are alternately arranged around a pair of ring windings in each phase to make use of the entire rotor flux that eliminates end windings. Analytical design considerations and finite-element methods are used for an optimized design of a scooter in-wheel motor. Simulation results from finite element analysis (FEA) show that the motor achieved comparable torque density to conventional rare-earth permanent magnet (PM) machines. This machine is a viable candidate for direct-drive applications with low cost and high torque density.
A novel transverse flux machine for vehicle traction aplications
2015 IEEE Power & Energy Society General Meeting, 2015
A novel transverse flux machine topology for electric vehicle traction applications using ferrite magnets is presented in this paper. The proposed transverse flux topology utilizes novel magnet arrangements in the rotor that are similar to the Halbach array to boost flux linkage; on the stator side, cores are alternately arranged around a pair of ring windings in each phase to make use of the entire rotor flux that eliminates end windings. Analytical design considerations and finite-element methods are used for an optimized design of a scooter in-wheel motor. Simulation results from finite element analysis (FEA) show that the motor achieved comparable torque density to conventional rare-earth permanent magnet (PM) machines. This machine is a viable candidate for direct-drive applications with low cost and high torque density.
A Review of Transverse Flux Machines Topologies and Design
Energies
High torque and power density are unique merits of transverse flux machines (TFMs). TFMs are particularly suitable for use in direct-drive systems, that is, those power systems with no gearbox between the electric machine and the prime mover or load. Variable speed wind turbines and in-wheel traction seem to be great-potential applications for TFMs. Nevertheless, the cogging torque, efficiency, power factor and manufacturing of TFMs should still be improved. In this paper, a comprehensive review of TFMs topologies and design is made, dealing with TFM applications, topologies, operation, design and modeling.
Design Considerations of Permanent Magnet Transverse Flux Machines
IEEE Transactions on Magnetics, 2000
-drive applications. Due to its complicated 3-D flux components, design and design optimization of a PMTFM is more difficult and time consuming than for radial flux electrical machines. This paper addresses two important design considerations for PMTFM-the influence of permanent magnet leakage flux, which plays an important role in the determination of machine output torque, and the leakage inductance. A new simple method to provide a quick estimation of the armature leakage inductance is proposed, avoiding use of complicated 3-D equivalent reluctance network model to estimate the circumferential armature leakage flux component, and the pole face fringing flux component. Analysis results are supported by 2-D, and 3-D finite element (FE) analysis results, and measurement results on a prototype surface-mounted PMTFM. Index Terms-Inductance, leakage flux, permanent magnet, transverse flux machine.
A Novel Approach to Transverse Flux Machine Construction
Energies, 2021
The article presents a concept for a new design of the well-known Transverse Flux Machine (TFM) made with the use of a flat core used in classical electrical machines. The proposed design was first analytically verified and was subsequently verified using the finite element method, which fully corroborated the results. The simulations show that a set of three single-phase TFM machines with slotted flat rotor yokes generates a torque over three times greater than that of an induction motor and twice as large as Fractional Slot Concentrated Winding—Permanent Magnet Synchronous Machines (FSCW-PMSM). The performed comparative calculations confirmed that the torque generated by machines operating on principles similar to TFM can generate a torque much greater than those currently in common use.
Comparative review of disk type and unconventional transverse flux machines: performance analysis
TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES
Transverse flux machines (TFM) can be designed with high pole numbers, so they are very useful in directdrive systems with high torque density. Although many TFM models have been proposed to date, no detailed classification and comparison has been made before. Conventional TFMs have a high power and torque density, but low power factors and high cogging torques have prevented them from being widely used. However, especially with the new disk type TFMs proposed in recent years and the methods developed, these drawbacks have been reduced. In this paper, the TFMs proposed in recent years have been classified and their performances in terms of power factor, cogging torque, torque density, and efficiency have been examined. According to the results of this review, the performances of the new generation TFMs are competitive. Especially double-sided disk type TFMs are seen as an important topology with their high magnet utilization and flexibility in design.
An Insight into Torque Production and Power Factor in Transverse-Flux Machines
IEEE Transactions on Industry Applications, 2017
Despite transverse flux machines (TFMs) being intrinsically three-dimensional, it is still possible to model them analytically using relatively simple models. This paper aims to provide an insight into the behaviour of TFMs using a compact equation, which relates torque to the electric and magnetic loadings of the machine and a flux factor. The flux factor is also used to estimate the flux linkage and therefore the power factor of this kind of machines. It is shown that the low power factor of TFMs is not only due to leakage but also due to the nature of the electromagnetic interaction that takes place. The TFM developed at the University of Southampton is used as the basis of a case study to illustrate the trade-off between torque density and power factor, and to provide some design guidelines. The analytical results are verified using finite elements analysis and experimental data. Index Terms-Analytical models, permanent magnet machines, power factor, torque, transverse-flux machines.
Analytical 3-D Design of a Transverse Flux Machine with High Power Factor
Low-speed high-torque applications, e.g. wind energy generation, favor high number of pole solu tions. for traditional radial or axial flux machines this leads to an increase in leakage flux while the power output does not increase. For Transverse Flux Machines (TFM) the increase in power output is proportional to the number of poles. However, large flux leakage is also present in TFMs, reducing their power factor and commercial application. Fast and accurate 3-D models are required to model this flux leakage. Finite Element Models (FEM) comprising a large number of elements are commonly used to calculate the 3-D flux density distribution. This approach is very time consuming with hours for a single solution. A fast and more accurate parameterized model is essential to minimize the machine volume while maintaining the required power factor. In this paper, a design approach is presented to obtain a TFM of a minimum volume with a predefined power factor. An analytical 3-D magnetic charge model is used to model a single magnetic period of the TFM. With the required power factor and the obtained flux due to the magnets the coil dimensions are calculated. The performance of the single magnetic period of the TFM is used to determine the full machine dimensions.
A Comprehensive Analytical Sizing Methodology for Transverse and Radial Flux Machines
IEEE Access
Transverse flux machines have the potential to offer high torque density in direct-drive vehicle traction applications. Besides, sizing equations are a widespread technique for transverse flux machines design, as their computational cost is much lower than the finite element method. In this paper a novel analytical sizing methodology for transverse and radial flux machines is presented, focusing on the current load and the pole length factor as the main design parameters. The motor specifications are intended for a light-duty electric vehicle application. As transverse flux machines have a single, hoop-shaped coil per phase that embraces the flux of all the pole pairs, their principle of operation and therefore their sizing equations differ from radial flux machines. The proposed analytical method allows to compare transverse and radial flux machines easily through a similarity analysis and a parametric study. Furthermore, the discrepancies between the analytical model and the finite element method are quantified and then included in previous equations. Then the analytical model is optimized with a multiobjective genetic algorithm in the final stage. According to the sizing methodology presented here, transverse flux machines have a superior performance than radial flux machines in terms of torque density and efficiency. INDEX TERMS Analytical sizing equations, electric vehicles, finite element method, multiobjective genetic algorithm, permanent magnet synchronous machines, transverse flux machines.