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Proceedings ArticleDOI

Effect of Lateral and Angular Misalignments on Power Transfer Efficiency of a Wireless EV Charging System

TL;DR: In this article, the authors presented the simulation analysis of various factors, which effects power transfer efficiency (PTE) in the practical scenario of WPT, and provided the effect of various cores and aluminum shielding on PTE for distinct air gaps.
Abstract: Wireless power transfer (WPT) is an emerging technology that could lead to the breakthrough of plug-in Electric Vehicles (EVs). It enables transfer of electric power from one coil to the other based on the principle of electromagnetic induction. Inductive coupling (IC) and magnetic resonance coupling (MRC) are the two main methods of WPT. In this paper, MRC technique is used to effectively transfer power over large air gaps. Low power transfer efficiency (PTE) is the major challenge in WPT charged EVs. This may causes due to misalignment between the transmitter (Tx) and the receiver (Rx) coils. Lateral and angular are two commonly occurring misalignments in the practical scenario of WPTS. This paper presents the simulation analysis of various factors, which effects PTE. In the analysis, the lateral misalignments are performed for distinct airgaps between Tx and Rx. Various modes of angular misalignments are presented for a fixed value of airgap between coils. In addition, the paper provides the effect of various cores and aluminum shielding on PTE for distinct air gaps are documented.
Citations
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Proceedings ArticleDOI
24 Nov 2022
TL;DR: In this article , the effects of lateral and angular misalignment on the wireless power transfer (WPT) system were investigated. And the results showed the insight to characterize the type of misalignments and its quantitative evaluation, so the transmission efficiency can be improved, and an overcurrent can be prevented in system by adapting a proper compensation topology.
Abstract: In this paper, we have investigated effects of lateral and angular misalignment on the wireless power transfer (WPT) system. The parameters of electric circuit model and the magnetic field distribution was obtained under misalignments. Coupling coefficient, transmission efficiency, current in the coil were analyzed. Also, the magnetic field perpendicular to the receiving coil surface was calculated. The results can show the insight to characterize the type of misalignments and its quantitative evaluation, so the transmission efficiency can be improved, and an overcurrent can be prevented in system by adapting a proper compensation topology.
Journal ArticleDOI
TL;DR: In this article , a novel analytical model that calculates the mutual inductance between two non-identical n-sided polygonal planar coils located in arbitrary position in 3D space is presented.
Abstract: Mutual inductance (MI) calculation is of great importance, because there are many systems that operate on the principle of inductive coupling. This paper presents a novel analytical model that calculates the MI between two non-identical n-sided polygonal planar coils located in arbitrary position in 3D space. The model depends upon misalignment of both the primary and the secondary coils of a wireless power transfer (WPT) system operating based on inductive coupling. The polygonal coils used in this model may differ from each other in terms of size, shape and turns number. The misalignment cases considered in the proposed model include lateral, angular, lateral-angular and vertical distance variation between the primary and secondary coils. Based on Stokes Theorem, instead of using the magnetic flux density vector, the magnetic vector potential (MVP) is used to reach the required magnetic flux in the calculation of the MI. A single analytical solution function that can calculate the MI between two planar polygonal coils of any shape in a simple manner and short time duration is obtained by performing difficult mathematical operations through MVP. Results obtained from the developed new model are compared with finite element analysis (FEA), experimental and other studies in the literature. The good agreement of the results of this study with the other results has proved the accuracy and validity of the proposed new analytical model.
Journal ArticleDOI
TL;DR: In this paper , a novel analytical model that calculates the mutual inductance between two n-sided polygonal planar coils located in an arbitrary position in 3D space is presented.
Abstract: Mutual inductance (MI) calculation is of great importance, because there are many systems that operate on the principle of inductive coupling. This article presents a novel analytical model that calculates the MI between two nonidentical n-sided polygonal planar coils located in an arbitrary position in 3-D space. The model depends upon the misalignment of both the primary and the secondary coils of a wireless power transfer system operating based on inductive coupling. The polygonal coils used in this model may differ from each other in terms of size, shape, and turns number. The misalignment cases considered in the proposed model include lateral, angular, lateral–angular, and vertical distance variation between the primary and secondary coils. Based on Stokes theorem, instead of using the magnetic flux density vector, the magnetic vector potential (MVP) is used to reach the required magnetic flux in the calculation of the MI. A single analytical solution function that can calculate the MI between two planar polygonal coils of any shape in a simple manner and short time duration is obtained by performing difficult mathematical operations through MVP. Results obtained from the developed new model are compared with finite element analysis, and experimental and other studies in the literature. The good agreement of the results of this study with the other results has proved the accuracy and validity of the proposed new analytical model.
References
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Journal ArticleDOI
TL;DR: In this paper, the authors reviewed the technologies in the wireless power transfer (WPT) area applicable to electric vehicle (EV) wireless charging, and the obstacles of charging time, range, and cost can be easily mitigated.
Abstract: Wireless power transfer (WPT) using magnetic resonance is the technology which could set human free from the annoying wires. In fact, the WPT adopts the same basic theory which has already been developed for at least 30 years with the term inductive power transfer. WPT technology is developing rapidly in recent years. At kilowatts power level, the transfer distance increases from several millimeters to several hundred millimeters with a grid to load efficiency above 90%. The advances make the WPT very attractive to the electric vehicle (EV) charging applications in both stationary and dynamic charging scenarios. This paper reviewed the technologies in the WPT area applicable to EV wireless charging. By introducing WPT in EVs, the obstacles of charging time, range, and cost can be easily mitigated. Battery technology is no longer relevant in the mass market penetration of EVs. It is hoped that researchers could be encouraged by the state-of-the-art achievements, and push forward the further development of WPT as well as the expansion of EV.

1,603 citations


"Effect of Lateral and Angular Misal..." refers background in this paper

  • ...There are four simple and basic compensation topologies in the system [8]....

    [...]

Journal ArticleDOI
TL;DR: In this paper, the authors present simple and accurate expressions for the DC inductance of square, hexagonal, octagonal, and circular spiral inductors, and evaluate the accuracy of their expressions, as well as several previously published inductance expressions, in two ways: by comparison with three-dimensional field solver predictions and by contrast with their own measurements, and also previously published measurements.
Abstract: We present several new simple and accurate expressions for the DC inductance of square, hexagonal, octagonal, and circular spiral inductors. We evaluate the accuracy of our expressions, as well as several previously published inductance expressions, in two ways: by comparison with three-dimensional field solver predictions and by comparison with our own measurements, and also previously published measurements. Our simple expression matches the field solver inductance values typically within around 3%, about an order of magnitude better than the previously published expressions, which have typical errors ground 20% (or more). Comparison with measured values gives similar results: our expressions (and, indeed, the field solver results) match within around 5%, compared to errors of around 20% for the previously published expressions. (We believe most of the additional errors in the comparison to published measured values is due to the variety of experimental conditions under which the inductance was measured.) Our simple expressions are accurate enough for design and optimization of inductors or of circuits incorporating inductors. Indeed, since inductor tolerance is typically on the order of several percent, "more accurate" expressions are not really needed in practice.

1,498 citations


"Effect of Lateral and Angular Misal..." refers background in this paper

  • ...In the structural analysis of the WPT system, fill factor ( ) is a key element which decides the self-inductance of the coil and it varies from one structure to another [11]....

    [...]

Journal ArticleDOI
TL;DR: In this article, the development history of inductive power transfer systems (IPTSs) is tracked from the origin of the RPEV in the 1890s to the recent road-powered electric vehicle (RPEV).
Abstract: Roadway-powered electric vehicles (RPEVs) are attractive candidates for future transportation because they do not rely on large and heavy batteries but directly and efficiently get power while moving along a road. The inductive power transfer systems (IPTSs) that have been widely used for the wireless powering of RPEVs are reviewed in this paper. The development history of the IPTS is tracked from the origin of the RPEV in the 1890s to the recent RPEV. Throughout its 100-year history, the size, weight, efficiency, air gap, lateral tolerance, electromagnetic force, and cost of the IPTS have been substantially improved, and now RPEVs are becoming more widely commercialized. Important milestones of the developments of the IPTS and RPEVs are summarized in this paper, focusing on recent developments of on-line electric vehicles that were first commercialized in 2013.

555 citations


"Effect of Lateral and Angular Misal..." refers methods in this paper

  • ...Here, aluminum rings (AR) are used for electromagnetic shielding of the system [3-4]....

    [...]

Journal ArticleDOI
TL;DR: A high-power high-efficiency wireless-power-transfer system using the class-E operation for transmitter via inductive coupling has been designed and fabricated using the proposed design approach.
Abstract: In this paper, a high-power high-efficiency wireless-power-transfer system using the class-E operation for transmitter via inductive coupling has been designed and fabricated using the proposed design approach. The system requires no complex external control system but relies on its natural impedance response to achieve the desired power-delivery profile across a wide range of load resistances while maintaining high efficiency to prevent any heating issues. The proposed system consists of multichannels with independent gate drive to control power delivery. The fabricated system is compact and capable of 295 W of power delivery at 75.7% efficiency with forced air cooling and of 69 W of power delivery at 74.2% efficiency with convection cooling. This is the highest power and efficiency of a loosely coupled planar wireless-power-transfer system reported to date.

520 citations

Journal ArticleDOI
TL;DR: In this article, the authors proposed a new method to integrate the compensated coil into the main coil structure, which not only makes the system more compact, but also the extra coupling effects resulting from the integration are either eliminated or minimized to a negligible level.
Abstract: There is a need for charging electric vehicles (EVs) wirelessly since it provides a more convenient, reliable, and safer charging option for EV customers. A wireless charging system using a double-sided LCC compensation topology is proven to be highly efficient; however, the large volume induced by the compensation coils is a drawback. In order to make the system more compact, this paper proposes a new method to integrate the compensated coil into the main coil structure. With the proposed method, not only is the system more compact, but also the extra coupling effects resulting from the integration are either eliminated or minimized to a negligible level. Three-dimensional finite-element analysis tool ANSYS MAXWELL is employed to optimize the integrated coils, and detailed design procedures on improving system efficiency are also given in this paper. The wireless charging system with the proposed integration method is able to transfer 3.0 kW with 95.5% efficiency (overall dc to dc) at an air gap of 150 mm.

245 citations


"Effect of Lateral and Angular Misal..." refers methods in this paper

  • ...Here, aluminum rings (AR) are used for electromagnetic shielding of the system [3-4]....

    [...]