Hexagonal Coil Research Articles

Optimal Design of Transmission Characteristics for Hexagonal Coil Wireless Power Transfer System Based on Genetic Algorithm

Effective optimization methods are used to guide the optimal design of coil parameters, which is significant for improving the transmission performance of the wireless power transfer (WPT) system. Traditional methods mostly rely on the exhaustive attack method and finite element analysis (FEA) to achieve the coil parameter design, which have the disadvantages of complex modeling and time-consumption. To overcome these limitations, this study proposes an optimization strategy based on the genetic algorithm (GA), which considers the actual requirements of the efficiency and power of the WPT system. First, a direct integration method is proposed to simplify the analytical solution process of the mutual inductance between the hexagonal coils. Based on the mutual inductance model, the transmission characteristics of the hexagonal coil WPT system are deeply analyzed by the control variable method. Most importantly, with the proposed optimization objective function and its constraints, the GA is used to automatically achieve multi-parameter optimization of the hexagonal coil. Finally, a 500 W WPT system experimental platform is established, and the experimental results verify the feasibility of the proposed optimization method.

Comparison of PCB Based Actuator Coils for Untethered Actuation

Recently magnetic actuation has become a versatile tool for manipulation on both the micro and macro scale. Due to the problems arising from scale, conventional electromagnet production methods are insufficient to produce the desired electromagnets to be used for this purpose. To solve the problems arising from this situation, researchers have been forced to work in alternative electromagnet production and application areas and paved the way for PCB-based electromagnetic actuators. For this reason, this article will explain the design principles of PCB planar coils for electromagnetic actuator applications and will provide the basis for later studies to create a coil matrix using this coil design and an actuator that can move ferromagnetic particles or magnets in the plane with this 2D coil matrix. The presented project design steps can be listed as follows; First of all, to be able to design a coil that consists of copper paths on the PCB and can meet expectations (homogeneous magnetic field, high magnetic force/current ratio). PCB coils consisting of square, circular and hexagonal coils are manufactured and various measurements are made. The measured results are consistent with the simulated results proving the accuracy and applicability of PCB coil actuators, and they are highly suitable for a new actuator version. In the tests carried out, coils energized with 1A can provide a maximum field strength of 1400 (A/m) and an average of 900 (A/m) and due to the lack of magnetic core, the created magnetic field has the shape of a bell. In order to overcome this situation, it is foreseen that making studies to increase the working current and, as a more important development, switching from the planar single-layer structure to the structure of two or more layers can increase the magnetic field produced by this type of coils, but this layer increase should take into account the cost and PCB production and application capabilities. should be made available.

A hexagonal high-performance transformer balun based on TSV technology for W-band application

Balun has been widely used for microwave circuits for its balance properties. The development of highly integrated RF systems has put forward higher requirements for superior performance and miniaturization of the balun. A compact broadband millimeter wave (MMW) transformer balun based on through silicon via (TSV) technology is proposed in this letter. Compared with the traditional balun, the proposed balun impedance ratio is 4:1, and the use of hexagonal coil winding significantly reduces its area and improves its performance. It is shown that the proposed balun has a magnitude imbalance of 0.64dB and a phase imbalance of 2.5° at 81.5-93GHz. A return loss of greater than 15dB is obtained for the frequency band ranges from 82.1-88.6 GHz. Furthermore, the area of balun is only 0.201×0.29mm2 (0.2×0.29λg2).

Design Methodology of Free-Positioning Nonoverlapping Wireless Charging for Consumer Electronics Based on Antiparallel Windings

Free positioning wireless charging for consumer electronics allows the devices to be charged at arbitrary positions and angles to improve user experience. However, a user-initiated sudden movement of the device during charging can cause hazards due to the abrupt variation of the coupling coefficient. To solve this issue, the coupling coefficient variation at different positions should be mitigated, which is also good for the design and high-efficiency operation of power electronics converters. This article proposes a design methodology to employ antiparallel windings to smooth the coupling coefficient variation over different positions by reducing the coupling coefficient at central positions and enhancing it at boundary positions. Two optimization methods are proposed: turn-by-turn optimization and winding-by-winding optimization. A design flow is offered. The hexagonal coil is compared with the square coil and proved to achieve better performance than the latter. An experimental prototype is implemented to validate the effectiveness of the proposed design methodology.

A 1-kW wireless power transfer system for electric vehicle charging with hexagonal flat spiral coil

Wireless power transfer (WPT) technology is getting more attention in these days as a clean, safe, and easy alternative to charging batteries in several power levels. Different coil types and system structures have been proposed in the literature. Hexagonal coils, which have a common usage for low power applications, have not been well studied for high and mid power applications such as in electric vehicle (EV) battery charging. In order to fill this knowledge gap, the self and mutual inductance equations of a hexagonal coil are obtained, and these equations have been used to design a 1 kW WPT system with hexagonal coils for a mid-power stage EV charging. The theoretical and simulation results have been validated with an implementation in the laboratory and a DC-to-DC power efficiency of 85% is achieved across a 10 cm air gap between the perfect aligned coils. The misalignment performance of the system was observed for different positioning of the secondary coil, and the output power variation is given. In addition, the effect of shielding on magnetic field exposition of a driver sitting in an EV was obtained, and these simulation results were compared in order to check the compliance with international health standards.

Improvement of power transfer efficiency of hexagonal coil arrays in misalignment conditions

<span>Wireless charging by transferring energy between two objects using electromagnetic fields commonly called Wireless power transfer is an alternative technology that is physically installed in an electric vehicle (EV) to charge. Parking alignment is a very important factor in driver behavior that affects Power transfer efficiency (PTE). The proposed hexagonal coil array design in this experiment is to optimize PTE and receiver coil size. The experimental results show that PTE in the tangential boundary plane Misalignment increases by 5-10% when compared to coil array circles and increases by 82% when compared to single coil circles. </span>

Analysis of Coil Parameters and Comparison of Circular, Rectangular, and Hexagonal Coils Used in WPT System for Electric Vehicle Charging

In this paper, the major factors that affect the performance of wireless power transfer systems, such as coil inner radius and coil number of turns, are discussed. A comparison of three coil shapes covering the coreless case, the case with ferrite, and the case with ferrite and aluminum is also carried out. Another comparison is proposed by addressing the combination of different coil shapes in the wireless power transfer (WPT)system. The analysis covers the coupling coefficient, the mutual inductance, and the self-inductance. Due to the complexity of calculating these parameters, the finite element analysis (FEA) method is adopted by using the Ansys Maxwell software. An introduction to the typical WPT system for electric vehicle charging is also presented.

A new semi-analytical approach for self and mutual inductance calculation of hexagonal spiral coil used in wireless power transfer systems

Several methods have been proposed in the literature for the calculation of self and mutual inductance. These methods include the use of complex integral analysis, the necessity of having primary and secondary coils with the same dimensions and the limitations of the ratio of the coil dimension to the distance between the coils. To overcome these restrictions, a new semi-analytical estimation method has been proposed in this paper. Calculation the self and mutual inductance by using the same basic formula which is based on Biot Savart Law prevents the formation of complex integrals and helps create a simple solution method. In order to verify the results obtained with the analytical approach, two hexagonal coils with 10 and 20 cm outer side lengths were produced by using litz wire with a conductive cross section of 1.78 mm2. The results obtained with the new approach are compared with the finite element analysis, other work presented in the literature and experimental results in order to prove the accuracy of the proposed method.

A tactile sensor based on magneto-sensitive elastomer to determine the position of an indentation

Abstract. In this paper, we investigate the capabilities of a tactile sensor based on magneto-sensitive elastomers (MSEs). The main feature of the sensor is the determination of the position of indentation. The principle is based on inductance measurements of multiple planar coils and a soft magneto-sensitive layer. The proposed prototype consists of a linear array of hexagonal coils with overlapping sections. First, the results of the experiments are presented, which include a sampling of a sensor region with indentations of constant depth. Subsequently, we introduce a mathematical model based on the bell-shaped flux density distribution of a planar coil. This model consists of ellipse equations with three parameters and a polynomial fit for each parameter. Finally, solving the system of equations results in the determination of the x coordinate of the indentation.

Energy Efficiency Analysis through Misalignment on New Design of Hexagonal Coil Array in Wireless Power Transfer

The global transportation revolution accelerates the growth of the Electric Vehicle (EV) market. Wireless Power Transfer Technology (WPT) is part of an alternative solution to replace charging by cable. In its implementation the driver's parking behavior affects Power Transfer Efficiency (PTE) due to frequently misalignment. A new coil array design proposed to optimize PTE and reduce the size of receiver coil. Receiver and transmitter circuits designed to simulate parking conditions and parking lots in small scale settings to get PTE data. Experimental results show that PTE increased by 10% in the center of the coil design and 82% during misalignment on a radius array against single loop coil. In the area of Misalignment tangential boundary, efficiency increased by 5-10% compared to circular coil arrays. The proposed novel coil series achieves a higher overall PTE than a single coil design and an increase in PTE in the tangential boundary misalignment when compared to circular coil arrays.

Designing and CFD Analysis of Table Top Refrigerator Hexagonal Coil Crossection

In the Present study CFD analysis has been performed on evaporator unit. Tabletop refrigerators are the common house hold unit used in almost all houses. Evaporator and Condenser unit is the main functioning unit of refrigerator system used for the cooling applications. With the increase of modernization use of refrigerator system has rapidly increases due to the reason a lot of researches are prevailing on refrigerator systems. With the updating in technologies almost all the refrigerators require performing with high efficiency and low power consumption. Most researches are going on to increase the heat transfer and heat dissipation in refrigerator systems. In the current study a table refrigerator is selected for the study purpose where effects of different cross sections of evaporator coil has been studied. In the design portion some changes have been made in the material of heating plate to have high transfer of heat from plate to evaporator coil. For the complete study CATIA V5 is used for the modelling purpose and Ansys Fluent is used for the CFD analysis Procedure where hexagonal cross section of evaporator coil shows the most efficient results.

A polygonal double-layer coil design for high-efficiency wireless power transfer

In this work, we present a novel coil structure for the design of Wireless Power Transfer (WPT) systems via magnetic resonant coupling. The new coil consists of two layers of flat polygonal windings in square, pentagonal and hexagonal shapes. The double-layer coil can be conveniently fabricated using the print circuit broad (PCB) technology. In our design, we include an angle between the two layers which can be adjusted to change the area of inter-layer overlap. This unique structure is thoroughly investigated with respect to the quality factor Q and the power transfer efficiency (PTE) using the finite element method (FEM). An equivalent circuit is derived and used to explain the properties of the angularly shifted double-layer coil theoretically. Comparative experiments are conducted from which the performance of the new coil is evaluated quantitatively. Our results have shown that an increased shift angle improves the Q-factor, and the optimal PTE is achieved when the angle reaches the maximum. When compared to the pentagonal and hexagonal coils, the square coil achieves the highest PTE due to its lowest parasitic capacitive effects. In summary, our new coil design improves the performance of WPT systems and allows a formal design procedure for optimization in a given application.

Coil Array Structures Compared for Contactless Battery Charging Platform

We propose two new coil topologies for a contactless battery charging platform. The new topologies consist of square printed circuit board (PCB) coils, grouped in two layers on a PCB. We compare the new topologies to each other and to a previously published topology that consists of three layers of hexagonal coils. For each topology, the magnetic flux density is calculated above the coil layers. In addition, the position dependence of the flux linkage between the primary coil array and a secondary coil is simulated and compared for all three topologies. For one of the new topologies, we compare the simulations with measurements.

ABA type liquid crystalline triblock copolymers by combination of living cationic polymerizaition and ATRP: synthesis and self-assembly.

Lamellar and hexagonal-coil-cylinder self-assembled structures of ABA type triblock copolymers containing mesogen-jacketed liquid crystalline polymer (MJLCP) as the rod block, and polyisobutylene (PIB) as the coil middle block were discovered. PIB was synthesized by living cationic polymerization of isobutylene initiated by 1,4-bis(2-chloro-2-propyl)benzene (p-DCC), and then a small amount of styrene was introduced at the end of the PIB chains to form the difunctional PIB macroinitiator with -CH2CH(C6H5)Cl end groups for further atom transfer radical polymerization (ATRP). 2,5-Bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS) was block-copolymerized from the difunctional PIB macroinitiators at 110 °C. The molecular characterization of the triblock copolymers was performed with 1H NMR, 13C NMR, gel permeation chromatography (GPC), and thermogravimetric analysis (TGA). Their phase structures and transitions were investigated by differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), and polarized optical microscopy experiments. It was demonstrated that the triblock copolymers formed lamellar structures at moderate rod fractions and hexagonal coil cylinders in the rod matrix at high rod fractions. The d-spacing of the microphase-separated structures was influenced by the liquid crystalline phase of rod-like PMPCS blocks.

Hexagonal zero mode TEM coil: A single‐channel coil design for imaging multiple small animals

A novel hexagonal coil design for simultaneous imaging of multiple small animals is presented. The design is based on a coaxial cavity and utilizes the magnetic field formed between two coaxial conductors with hexagonal cross-sections. An analytical solution describing the B(1) field between conductors of the hexagonal coil was found from the Biot-Savart law. Both experimental results and analytical calculations showed a variation in the B(1) field within the imaging region of less than 10%. Numerical calculations predicted approximately 35% improvement in B(1) field homogeneity with the hexagonal coil design compared to a cylindrical coaxial cavity design. The experimentally-measured signal-to-noise ratio (SNR) of the hexagonal coil loaded with six 50-mM phantoms was only 4-5% lower than that of a single parallel plate resonator loaded with one phantom. In vivo spin-echo (SE) images of six 7-day-old rat pups acquired simultaneously demonstrated sufficient SNR for microimaging. The construction scheme of the coil, simple methods for tuning and matching, and an anesthesia device and animal holder designed for the coil are described. The hexagonal coil design utilizes a single receiver and allows for simultaneous imaging of six small animals with no significant compromise in SNR.