Transmitter arrangement, wireless power transfer system and methods of forming the same

Abstract

Various embodiments may relate to a transmitter arrangement. The transmitter arrangement may include a source resonator configured to be connected to an alternating (AC) voltage source, the source resonator including a planar source coil. The transmitter arrangement may also include an amplifier resonator configured to be wirelessly coupled to the source resonator, the amplifier resonator including an amplifier coil. The transmitter arrangement may be configured such that a resonant angular frequency of the amplifier resonator is greater than a resonant system angular frequency of the source resonator to increase an output power and extend a power transfer distance.

Description

TRANSMITTER ARRANGEMENT, WIRELESS POWER TRANSFER SYSTEM AND METHODS OF FORMING THE SAMECROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority of Singapore application No. 10202401411Y filed May 20, 2024, the contents of it being hereby incorporated by reference in its entirety for all purposes.TECHNICAL FIELD

[0002] Various embodiments of this disclosure may relate to a transmitter arrangement. Various embodiments of this disclosure may relate to a method of forming a transmitter arrangement. Various embodiments of this disclosure may relate to a wireless power transfer (WPT) system. Various embodiments of this disclosure may relate to a method of forming a wireless power transfer (WPT) system.BACKGROUND

[0003] Inductive-type wireless power transfer (WPT) technology is increasingly recognized as a viable alternative or complement to heavy and bulky batteries in emerging power devices, such as portable tools, robotics, and electric vehicles (EVs). Transmission distance remains a critical concern in WPT systems due to leakage flux. As the distance between two coupled coils increases, the output power of the WPT system decreases significantly. FIG. 1 is a plot of output power as a function of distance illustrating the relationship between the output power and distance between two coupled coils of typical wireless power transfer (WPT) systems. Consequently, WPT systems are usually used in applications where the transfer distance is shorter than the coil dimension.

[0004] To maintain sufficient power supply over relatively long galvanic gaps, various types of power amplifier coils, known as relay coils, have been proposed. A four-coil WPT system has previously been described, where two relay coils are placed alongside the source and receiver coils. This configuration achieves approximately 40% transmission efficiency and delivers 60 W of output power at a resonance frequency of 10 MHz, with a transmission distance of 2 m. Subsequent studies have highlighted the critical role of the additional relaycoils in impedance matching within four-coil WPT systems. A previous study has also disclosed a tuning method to increase power transfer efficiency. Detailed explanations of impedance matching for four-coil WPT systems have been described in another study to provide detailed explanations of impedance matching for four-coil WPT systems, showing that transmission efficiency can be enhanced by adjusting the distance between the transmitter coil and its adjacent relay or the receiver coil and its corresponding relay. Similar to the abovementioned study, another study has indicated that the distance between the relay coil and the receiver coil is adjusted to achieve the optimal mutual inductance for enhancing efficiency. A separate study has presented a formulation for power transfer efficiency based on reflected load theory and coupled-mode theory. In yet another study, two relay coils are positioned on the transmitter side, boosting the apparent coupling coefficient at the operating frequency and achieving higher system efficiency compared to conventional four-coil systems.

[0005] It has been noted that three-coil WPT systems can achieve higher output power than four-coil systems. Thus, three-coil WPT systems have been explored for use in implantable devices. There have also been comparisons between the efficiency of two-coil and three-coil WPT systems. It is shown that three-coil WPT systems are more energy-efficient than two-coil systems, as the relay coil in the three-coil system shifts current stress from the transmitter and generates a large relay current to maximize magnetic coupling with the receiver. The concept of a critical coupling coefficient is introduced as the threshold at which two- and three-coil systems achieve the same transmission efficiency. The three-coil system exhibits higher efficiency when the critical coupling coefficient is lower than this threshold. The three-coil WPT system is demonstrated to reduce current stress and electromagnetic field emissions more effectively under misalignment compared to two-coil systems. Beyond three and four-coil systems, multiple relay coils can be strategically placed between the source and receiver coils to form a domino WPT system. The WPT systems discussed above typically use planar relay designs with capacitors compensated at resonant frequencies.SUMMARY

[0006] Various embodiments may relate to a transmitter arrangement. The transmitter arrangement may include a source resonator configured to be connected to an alternating (AC) voltage source, the source resonator including a planar source coil. The transmitter arrangement may also include an amplifier resonator configured to be wirelessly coupled to the sourceresonator, the amplifier resonator including an amplifier coil. The transmitter arrangement may be configured such that a resonant angular frequency of the amplifier resonator is greater than a resonant system angular frequency of the source resonator to increase an output power and extend a power transfer distance.

[0007] Various embodiments may relate to a wireless power transfer (WPT) system. The wireless power transfer (WPT) system may include a transmitter arrangement as described herein. The wireless power transfer (WPT) system may also include a receiver resonator configured to be wirelessly coupled to the transmitter arrangement, the receiver resonator including a receiver coil.

[0008] Various embodiments may relate to a method of forming a transmitter arrangement. The method may include providing a source resonator configured to be connected to an alternating (AC) voltage source, the source resonator including a planar source coil. The method may also include coupling an amplifier resonator to the source resonator wirelessly, the amplifier resonator including an amplifier coil. The transmitter arrangement may be configured such that a resonant angular frequency of the amplifier resonator is greater than a resonant system angular frequency of the source resonator to increase an output power and extend a power transfer distance.

[0009] Various embodiments may relate to a method of forming a wireless power transfer (WPT) system. The method may include providing a transmitter arrangement as described herein. The method may also include coupling a receiver resonator to the transmitter arrangement wirelessly, the receiver resonator including a receiver coil.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily drawn to scale, emphasis instead generally being placed upon illustrating the principles of various embodiments. In the following description, various embodiments of the invention arc described with reference to the following drawings.FIG. 1 is a plot of output power as a function of distance illustrating the relationship between the output power and distance between two coupled coils of typical wireless power transfer (WPT) systems.FIG. 2A shows a general illustration of a transmitter arrangement according to various embodiments.FIG. 2B shows a general illustration of a wireless power transfer (WPT) system according to various embodiments.FIG. 3 shows a general illustration of a method of forming a transmitter arrangement according to various embodiments.FIG. 4 shows a general illustration of a method of forming a wireless power transfer (WPT) system according to various embodiments.FIG. 5A shows a wireless power transfer (WPT) system including a transmitter arrangement including a source coil and a planar amplifier coil according to various embodiments.FIG. 5B shows a perspective view, a top view and a front view of the planar amplifier coil shown in FIG. 5A according to various embodiments.FIG. 6A shows a wireless power transfer (WPT) system including a transmitter arrangement including a source coil and a conical amplifier coil according to various embodiments.FIG. 6B shows a perspective view, a top view and a front view of the conical amplifier coil shown in FIG. 6A according to various embodiments.FIG. 7 shows an equivalent circuit diagram of the wireless power transfer (WPT) system according to various embodiments.FIG. 8A shows a three-dimensional plot of load RL (in ohms or Ω) as a function of ratio ωa / ωo and ratio a illustrating relationship between a and ( ωa / ωo under different load conditions when ki = 0.3 according to various embodiments.FIG. 8B shows a three-dimensional plot of load RL (in ohms or Ω) as a function of ratio ωa / ωo,, and ratio a illustrating relationship between a and ωa / ωo under different load conditions when ki = 0.2 according to various embodiments.FIG. 9A shows a table illustrating main parameters used in simulation of four models according to various embodiments.FIG. 9B shows reference model A, comparison model B, as well as models of the wireless power transfer (WPT) systems models C and D according to various embodiments.FIG. 9C shows the simulated magnetic field distributions for (a) Model A, (b) Model B as well as (c) Model C and (d) Model D as illustrated in FIG. 9B according to various embodiments.FIG. 9D shows a plot of output power (in Watts or W) as a function of load resistance RL (in ohms or Ω) comparing the output power of the four models in simulation according to various embodiments.FIG. 10A shows a photograph of the experimental setup according to various embodiments. FIG. 10B illustrates (a) dimensions of the ferrite, (b) dimensions of the planar amplifier coil, and (c) dimensions of the conical amplifier coil used in the experiment according to various embodiments.FIG. 10C shows the main experimental parameters of the wireless power transfer (WPT) systems according to various embodiments.FIG. 10D shows a plot of output power (in Watts or W) as a function of load resistance RL (in ohms or Ω) comparing the experimental output power of the four models according to various embodiments.FIG. 10E shows a plot of efficiency (in percent or %) as a function of load resistance RL (in ohms or Ω) comparing the experimental system efficiency (direct current - direct current or de - de) of the four models according to various embodiments.FIG. 11 shows a plot of distance (in centimeters or cm) as a function of model comparing the galvanic gaps of the four models for the same output power according to various embodiments.DESCRIPTION

[0011] The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the invention. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

[0012] Features that arc described in the context of an embodiment may correspondingly be applicable to the same or similar features in the other embodiments. Features that are described in the context of an embodiment may correspondingly be applicable to the other embodiments, even if not explicitly described in these other embodiments. Furthermore, additions and / orcombinations and / or aitcmativcs as described for a feature in the context of an embodiment may correspondingly be applicable to the same or similar feature in the other embodiments.

[0013] In the context of various embodiments, the articles “a”, “an” and “the” as used with regard to a feature or element include a reference to one or more of the features or elements.

[0014] In the context of various embodiments, the term “about” or “approximately” as applied to a numeric value encompasses the exact value and a reasonable variance, e.g., within 10% of the specified value.

[0015] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0016] By “comprising” it is meant including, but not limited to, whatever follows the word “comprising”. Thus, use of the term “comprising” indicates that the listed elements are required or mandatory, but that other elements are optional and may or may not be present.

[0017] By “consisting of” it is meant including, and limited to, whatever follows the phrase “consisting of’. Thus, the phrase “consisting of’ indicates that the listed elements are required or mandatory', and that no other elements may be present.

[0018] Embodiments described in the context of one of the arrangements / systems are analogously valid for the other arrangements / systems. Similarly, embodiments described in the context of a method are analogously valid for an arrangement / system, and vice versa.

[0019] Various embodiments may relate to a system where the amplifier / relay coil is compensated off the resonant frequency. The amplifier / relay coil may be positioned beneath the source / transmitting coil to avoid complexity of the receiver coil. Various embodiments may achieve significant improvements in both transmission distance and output power compared to traditional WPT systems.

[0020] FIG. 2A shows a general illustration of a transmitter arrangement according to various embodiments. The transmitter arrangement may include a source resonator 202 configured to be connected to an alternating (AC) voltage source, the source resonator 202 including a planar source coil. The transmitter arrangement may also include an amplifier resonator 204 configured to be wirelessly coupled to the source resonator 202, the amplifier resonator 204 including an amplifier coil. The transmitter arrangement may be configured such that a resonant angular frequency (cωaof the amplifier resonator is greater than a resonant system angular frequency (ωo) of the source resonator to increase an output power and extend a power transfer distance.

[0021] In other words, various embodiments may relate to a transmitter arrangement including a source resonator 202 with a planar source coil, and an amplifier resonator 204 with an amplifier coil. The resonant angular frequency (coa) of the amplifier resonator may be greater than a resonant system angular frequency (co0).

[0022] For avoidance of doubt, FIG. 2A seeks to illustrate some features of a transmitter arrangement according to various embodiments, and is not intended to limit, for instance, the size, shape, orientation, arrangement etc. of the various features.

[0023] In various embodiments, the amplifier resonator 204 and the source resonator 202 may be electrically isolated from each other. The amplifier resonator 204 and the source resonator 202 may be spaced apart from each other. The planar source coil and the amplifier coil may be spaced apart from each other.

[0024] In various embodiments, the amplifier resonator 204 and / or amplifier coil may be electrically isolated from an inverter or a power source.

[0025] In various embodiments, the source resonator 202 may have an inductor-capacitor- capacitor (LCC) compensation topology. In various embodiments, the source resonator 202 may include a first capacitor (Cs) connected in series with the planar source coil. The source resonator 202 may also include a second capacitor (Cfi) connected in parallel with the planar source coil and the first capacitor. The source resonator 202 may further include an inductor (Lfi) connected in series with an arrangement including the planar source coil, the first capacitor (Cs) and the second capacitor (Cfi).

[0026] In various embodiments, the amplifier resonator 204 may have a series-series (SS) compensation topology. In various embodiments, the amplifier resonator 204 may include a capacitor (Ca) connected in series with the amplifier coil.

[0027] In various embodiments, the planar source coil may be compensated at the resonant system angular frequency (m0).

[0028] In various embodiments, the amplifier coil may be compensated at above the resonant system angular frequency (m0).

[0029] The amplifier coil may be of any suitable shape. The amplifier coil may also be arranged at any suitable position relative to the planar source coil. Various embodiments may allow for a wide range of configurations to suit various design and functional requirements, further enhancing the versatility.

[0030] In various embodiments, the amplifier coil may be a planar amplifier coil. The planar amplifier coil may surround the planar source coil.

[0031] In various embodiments, the amplifier coil may be a conical amplifier coil. The conical amplifier coil may form a curved side surface of a truncated cone. The planar source coil may form a truncated surface of the truncated cone or a base surface of the truncated cone. In various other embodiments, the amplifier coil may be, for instance, a rectangular or a polygonal amplifier coil.

[0032] FIG. 2B shows a general illustration of a wireless power transfer (WPT) system according to various embodiments. The wireless power transfer (WPT) system may include a transmitter arrangement as described herein, i.e., including the source resonator 202 and the amplifier resonator 204 as shown in FIG. 2A. The wireless power transfer (WPT) system may also include a receiver resonator 206 configured to be wirelessly coupled to the transmitter arrangement, the receiver resonator 206 including a receiver coil.

[0033] In other words, various embodiments may relate to a transmitter arrangement as described herein and a receiver resonator 206.

[0034] For avoidance of doubt, FIG. 2B seeks to illustrate some features of a wireless power transfer (WPT) system according to various embodiments, and is not intended to limit, for instance, the size, shape, orientation, arrangement etc. of the various features.

[0035] In various embodiments, the receiver coil may be a planar receiver coil. The receiver coil may be parallel to and spaced apart from the planar source coil. The receiver coil may be electrically isolated from the planar source coil

[0036] In various embodiments, the receiver resonator 206 may have an inductor-capacitor- capacitor (LCC) compensation topology. In various embodiments, the receiver resonator 206 may include a first capacitor (Cr) connected in series with the receiver coil. The receiver resonator 206 may also include a second capacitor (Crz) connected in parallel with the receiver coil and the first capacitor. The receiver resonator 206 may additionally include an inductor (Lf?) connected in series with an arrangement including the receiver coil, the first capacitor (Cr) and the second capacitor (Cf12).

[0037] FIG. 3 shows a general illustration of a method of forming a transmitter arrangement according to various embodiments. The method may include, in 302, providing or forming a source resonator configured to be connected to an alternating (AC) voltage source, the source resonator including a planar source coil. The method may also include, in 304, coupling anamplifier resonator to the source resonator wirelessly, the amplifier resonator including an amplifier coil. The transmitter arrangement may be configured such that a resonant angular frequency (o»Q) of the amplifier resonator is greater than a resonant system angular frequency (6Joj of the source resonator to increase an output power and extend a power transfer distance.

[0038] In other words, various embodiments may relate to a method of forming a transmitter arrangement by forming or providing a source resonator and an amplifier resonator configured to be coupled wirelessly to the source resonator.

[0039] For avoidance of doubt, FIG. 3 is intended to illustrate steps of a method of forming a transmitter arrangement, and is not intended to limit the sequence of the various steps. The source resonator may be formed or provided before, after or at the same time as forming or providing the amplifier resonator.

[0040] In various embodiments, the amplifier resonator and the source resonator may be electrically isolated from each other.

[0041] In various embodiments, the amplifier resonator may be electrically isolated from an inverter or a power source.

[0042] In various embodiments, the source resonator may have an inductor-capacitor- capacitor (LCC) compensation topology.

[0043] In various embodiments, the source resonator may include a first capacitor (Cs) connected in series with the planar source coil. The source resonator may also include a second capacitor (Cf1) connected in parallel with the planar source coil and the first capacitor (Cs). The source resonator may additionally include an inductor (Ln) connected in series with an arrangement including the planar source coil, the first capacitor (Cs) and the second capacitor (Cfi).

[0044] In various embodiments, the amplifier resonator may have a series-series (SS) compensation topology.

[0045] In various embodiments, the amplifier resonator may include a capacitor (Ca) connected in series with the amplifier coil.

[0046] In various embodiments, the planar source coil may be compensated at the resonant system angular frequency (ωo ).

[0047] In various embodiments, the amplifier coil may be compensated at above the resonant system angular frequency (ωo ).

[0048] The amplifier coil may be of any suitable shape. The amplifier coil may also be arranged at any suitable position relative to the planar source coil.

[0049] In various embodiments, the amplifier coil may be a planar amplifier coil. The planar amplifier coil may surround the planar source coil.

[0050] In various embodiments, the amplifier coil may be a conical amplifier coil. The conical amplifier coil may form a curved side surface of a truncated cone. The planar source coil may form a truncated surface of the truncated cone or a base surface of the truncated cone.

[0051] FIG. 4 shows a general illustration of a method of forming a wireless power transfer (WPT) system according to various embodiments. The method may include, in 402, providing a transmitter arrangement as described herein. The method may also include, in 404, coupling a receiver resonator to the transmitter arrangement wirelessly, the receiver resonator including a receiver coil.

[0052] In other words, various embodiments may relate to a method of forming a wireless power transfer (WPT) system including providing or forming a transmitter arrangement and a receiver resonator configured to be coupled wirelessly to each other.

[0053] For avoidance of doubt, FIG. 4 is intended to illustrate steps of a method of forming a wireless power transfer (WPT) system, and is not intended to limit the sequence of the various steps. The transmitter arrangement may be provided or formed before, after or at the same time as providing or forming the receiver resonator.

[0054] In various embodiments, the receiver coil may be a planar receiver coil. The receiver coil may be parallel to and spaced apart from the planar source coil.

[0055] In various embodiments, the receiver resonator may have an inductor-capacitor- capacitor (LCC) compensation topology.

[0056] In various embodiments, the receiver resonator may include a first capacitor (Cr) connected in series with the receiver coil. The receiver resonator may also include a second capacitor (Cf2) connected in parallel with the receiver coil and the first capacitor. The receiver resonator may further include an inductor (Cf2) connected in series with an arrangement include the receiver coil, the first capacitor (Cr) and the second capacitor (Cf2).

[0057] FIG. 5A shows a wireless power transfer (WPT) system including a transmitter arrangement including a source coil 512 and a planar amplifier coil 514 according to various embodiments. As shown in FIG. 5 A, the source coil 512 and the planar amplifier coil 514 may not be connected. The WPT system may also include a receiver coil 516. The source coil 512may be a traditional planar transmitter coil placed on a top surface, while the planar amplifier coil 514 may be wound outside, i.e., surround, the planar source coil 512. FIG. 5B shows a perspective view, a top view and a front view of the planar amplifier coil 514 shown in FIG. 5A according to various embodiments. For the sake of clarity, the other components of the source resonator, the amplifier resonator and the receiving resonator, e.g., capacitors and inductors, are not illustrated in FIGS 5 A - B. n and n as shown in FIG. 5B denote, respectively, the inner radius and the outer radius of the planar amplifier coil 514.

[0058] FIG. 6A shows a wireless power transfer (WPT) system including a transmitter arrangement including a source coil 612 and a conical amplifier coil 614 according to various embodiments. As shown in FIG. 6A, the source coil 612 and the amplifier coil 614 may not be connected. The WPT system may also include a receiver coil 616. The source coil 612 may be a traditional planar transmitter coil placed on a top surface, while the amplifier coil 614 may be a conical coil, i.e., a coil that forms the curved side surface of a truncated cone. FIG. 6B shows a perspective view, a top view and a front view of the conical amplifier coil 614 shown in FIG. 6A according to various embodiments. For the sake of clarity, the other components of the source resonator, the amplifier resonator and the receiving resonator, e.g., capacitors and inductors, arc not illustrated in FIGS 6A - B. n and n as shown in FIG. 6B denote, respectively, the radius of the top surface (i.e., truncated surface) and the radius of the bottom surface (i.e., base surface) respectively of the truncated cone, h denotes the height of the truncated cone. While FIG. 6 A shows that the planar source coil 612 forms a truncated surface of the truncated cone, with the truncated surface facing the receiver coil 616, it may also be envisioned that in various other embodiments, the planar source coil 612 may form a base surface of the truncated cone, with the base surface facing the receiver coil 616.

[0059] FIG. 7 shows an equivalent circuit diagram of the wireless power transfer (WPT) system according to various embodiments. The source resonator 702 may have an inductorcapacitor-capacitor (LCC) compensation (or LCC -compensated) topology. Likewise, the receiver resonator 706 may have an inductor-capacitor-capacitor (LCC) compensation (or LCC-compensated) topology. The amplifier resonator 704 may have a series-series (SS) compensation topology (or a series-compensated topology).

[0060] The source resonator 702 may include a first capacitor (Cs) 722 connected in series with the planar source coil (Ls) 712, a second capacitor (Cfi) 732 connected in parallel with the planar source coil 712 and the first capacitor 722, and an inductor (Ln) 742 connected in serieswith an arrangement including the planar source coil 712, the first capacitor 722 and the second capacitor 732. The alternating voltage source vtmay be connected in series with the source resonator 702.

[0061] The amplifier resonator 704 may include a capacitor (Ca) 724 connected in series with the amplifier coil (La) 714. As shown in FIG. 7, the amplifier resonator 704 may not be connected to any power source (i.e., voltage source or current source) or other components, e.g., an inverter.

[0062] The receiver resonator 706 may include a first capacitor (Cr) 726 connected in scries with the receiver coil (Lr) 716, a second capacitor (Cf2) 736 connected in parallel with the receiver coil 716 and the first capacitor 726, and an inductor (Lf2) 746 connected in series with an arrangement including the receiver coil 716, the first capacitor 726 and the second capacitor 736. The load RL may be connected in series with the receiver resonator 706.

[0063] Mi is the mutual inductance between the source coil Ls712 and the receiver coil Lr716. M2 is the mutual inductance between the source coil Ls712 and the amplifier coil La714. M3 is the mutual inductance between the receiver coil Lr 716 and the amplifier coil La714.

[0064] In the source resonator 702, the source coil Ls712 may be compensated by the LCC components Cs722, Ln 742, and Cn 732. The parameters may be designed to satisfywhere is the resonant frequency. vtis the equivalent voltage source of thesystem. The compensation circuit design of the receiver resonator 706 may be similar to that of the source resonator 702. The receiver coil Lr 716 may be compensated by the LCC components Cr726, Lf2746, and Cf2736. The parameters may be designed to satisfyRL is the equivalent load resistance of the system. Based on (1) and (2), the excitation current (i.e., is) of the source coil 712 can be regarded as constant, which can be expressed asTo simplify the analysis without losing generality, Lfi and Lf2 may be designed to be the same as Lf 1Lf 2Lf. Based on Kirchhoffs law, the load current can be derived asThe current of the amplifier coil can be further derived aswhere is the equivalent impedance of the amplifier resonator. Bysubstituting (5) into (4). the root mean square (RMS) value of mean be derived as

[0065] If the amplifier coil is not used, the RMS value of m can be derived asThen, the ratio (i.e., a ) of the output current with and without using the amplifier resonator (i.e., a) can be derived based on (6) and (7) aswhere [I —TO further analyse the relationship between a and Xa, partial derivative of a with respect tocan be derived asAccording to (9), for X , a will increase when X;iis increased. Due isalways lower than . Therefore, the amplifier resonator will reduce the output powerof the system when . Based on (8), the partial derivative of a with respect tocan be derived asAccording to while it is negative Due. Thus, the amplifier would enhance theoutput power of the system when the maximal a can beobtained when Xasatisfies

[0066] The corresponding maximal a can be obtained as

[0067] To investigate the relationship between the resonant frequency of the amplifier resonator and the source resonator, the equivalent impedance of the amplifier resonator can be determined aswhere ωais the resonant angle frequency of the amplifier resonator. According to (11), if (i)ais designed to be greater thanis negative such that the output power of the system can be increased by including the amplifier resonator. According to (8), the output characteristics may be influenced by several parameters, including load resistance and mutual inductances. To illustrate the effective range of the amplifier, FIGS. 8A - B show the relationship between the output current ratio and the resonant frequency of the amplifier under different load and coupling conditions. FIG. 8A shows a three-dimensional plot of load RL (in ohms or Ω) as a function of ratioand ratio a illustrating relationship between a and under different load conditions when k1= 0.3 according to various embodiments. FIG. 8B shows a three-dimensional plot of load RL (in ohms or Ω) as a function of ratioand ratio a illustrating relationship betweenunder different load conditions when k1= 0.2 according to various embodiments. For simplification, it is assumed that the coupling coefficient between the source and the receiver (i.e., k1) and between the amplifier and the receiver (i.e., k3) are the same. The coupling between the source and the amplifier (i.e., k2) is strong, as the two coils are closely placed. FIG. 8A represents the WPT system with relatively strong coupling between the source and receiver. Clearly, there is a range where the ratio of the output current is greater than 1, with the maximum ratio reaching approximately 3 for. When the main coupling is reduced to 0.2, the effective range increases significantly, as shown in FIG. 8B. Therefore, the proposed transmitter design according to various embodiments may be better suited for long-distance wireless charging applications.

[0068] Simulations are conducted using a combination of Ansys Simplorer and Maxwell 2023R1. Four models were constructed in Maxwell, as illustrated in FIGS. 9A - B. FIG. 9A shows a table illustrating main parameters used in simulation of four models according tovarious embodiments. FIG. 9B shows reference model A, comparison model B, as well as models of the wireless power transfer (WPT) systems models C and D according to various embodiments. Reference model A is without auxiliary coils and materials (i.e., has only the conventional source coil and receiver coil), while comparison model B has a ferrite layer placed beneath the source coil to enhance the power transfer distance and output power.

[0069] The simulated magnetic flux densities are illustrated in FIG. 9C. FIG. 9C shows the simulated magnetic field distributions for (a) Model A, (b) Model B as well as (c) Model C and (d) Model D as illustrated in FIG. 9B according to various embodiments.

[0070] The corresponding magnetic flux densities of the four models with RL = 2Ω, are depicted in FIG. 9C. The magnetic flux densities of Model B, Model C, and Model D may be stronger than that of the reference Model A. The magnetic flux distribution of Model C may be similar to that of Model A, and may have a strong magnetic flux density at the edge of the coils. On the contrary, the magnetic flux densities in Model B and Model D may be more concentrated in the center.

[0071] The distance between the source coil and the receiver coil may be set to 8 cm. A double-sided LCC-compensated network may be implemented in Simplorer. An alternating current (AC) voltage source with a root-mcan-squarc (RMS) value of 5 V may be utilized. The RMS value of the excitation current for the source coil is about 0.5 A. Based on the SAE standard, the operating frequency and resonant frequencies of the source coil and receiver coil may be set to be 85 kHz. The resonant frequencies of the proposed amplifier resonators in the Model C and Model D may be 86 kHz.

[0072] FIG. 9D shows aplotof output power (in Watts or W) as a function of load resistance RL (in ohms or Ω) comparing the output power of the four models in simulation according to various embodiments. FIG. 9D is based on the parameters shown in FIG. 9A, but with load resistance (RL) varying from 2 Ω - 10 Ω. Compared to the reference Model A, the output power of Model B, Model C, and Model D may be increased. The proposed designs in the Model C and Model D may exhibit higher output power than the Model B with ferrites. The proposed design in the Model D may perform better than the proposed design in the Model C.

[0073] Experiments arc conducted on an LCC-LCC compensated WPT system according to various embodiments, as shown in FIG. 10A. FIG. 10A shows a photograph of the experimental setup according to various embodiments. Comparisons arc made among the WPT system without amplifier coils and ferrites (i.e., Model A), the WPT system with ferrites (i.e.,Model B), the WPT system with the proposed planar amplifier coil (i.c., Model C), and the WPT system with the proposed conical amplifier coil (i.e., Model D). The dimensions of the ferrite and amplifier coils arc provided in FIG. 10B. FIG. 10B illustrates (a) dimensions of the ferrite, (b) dimensions of the planar amplifier coil, and (c) dimensions of the conical amplifier coil used in the experiment according to various embodiments. The ferrite material (PC 95) has a thickness of 2 mm. The source coil and the conical amplifier coil are mounted on a truncated cone model fabricated using 3D printing technology with polylactic acid (PLA) material. The input direct current (DC) voltage may be set at 5 V. The operating frequency and resonant frequencies of the source coil and receiver coil may be set to be 85 kHz. The resonant frequencies of the amplifier resonators may be 86 kHz. The other parameters of the WPT system are listed in FIG. 10C. FIG. 10C shows the main experimental parameters of the wireless power transfer (WPT) systems according to various embodiments. The distance between the source coil and receiver coil may be set at 8 cm. The placement of the amplifiers and the ferrite may be directly beneath the source coil, separated by a minimal distance of 2 mm. The comparisons of experimental output power and efficiency arc illustrated in FIGS. 10D - E, respectively.

[0074] FIG. 10D shows a plot of output power (in Watts or W) as a function of load resistance RL (in ohms or Ω) comparing the experimental output power of the four models according to various embodiments. FIG. 10D illustrates that the average output power of the WPT systems across load resistances ranging from 1 Ω to 8 Ω are 0.41 W, 0.93 W, 6.83 W, and 8.51 W. The output power of the WPT systems with the proposed transmitter arrangements incorporating amplifier coils is enhanced by approximately 16.66 times and 20.76 times compared to the conventional system without amplifier coils.

[0075] FIG. 10E shows a plot of efficiency (in percent or %) as a function of load resistance RL (in ohms or Ω) comparing the experimental system efficiency (direct current - direct current or de - de) of the four models according to various embodiments. As shown in FIG. 10E, the use of ferrite may achieve the highest efficiency among all designs. The average efficiency across load resistances from 1 Ω to 8 Ω for Models A to D is measured as 67.4%, 76.1%, 50.4%, and 56.9%, respectively.

[0076] To achieve the same output power of 0.38 W with RL = 4 Ω, the charging distance among the four models arc 8 cm, 9.7 cm, 21.5 cm, and 22 cm, respectively. The comparisons are exhibited in FIG. 1 1 . FIG. 1 1 shows a plot of distance (in centimeters or cm) as a functionof model comparing the galvanic gaps of the four models for the same output power according to various embodiments. The charging distance of the proposed designs can be extended about 2.69 times and 2.75 times, respectively. The weights of the ferrite and amplifier coils used in the experiment are measured. The weights for the ferrite, planar amplifier coil, and the conical amplifier coil are 0.63 kg, 0.36 kg, and 0.43 kg, respectively. The conical amplifier coil is lighter than the ferrite by about 31.75%, but heavier than the planar amplifier coil due to the extra mass of the three dimensional (3D)-printed holder.

Claims

Claims1. A transmitter arrangement comprising: a source resonator configured to be connected to an alternating (AC) voltage source, the source resonator comprising a planar source coil; and an amplifier resonator configured to be wirelessly coupled to the source resonator, the amplifier resonator comprising an amplifier coil; wherein the transmitter arrangement is configured such that a resonant angular frequency of the amplifier resonator is greater than a resonant system angular frequency of the source resonator to increase an output power and extend a power transfer distance.

2. The transmitter arrangement according to claim 1, wherein the amplifier resonator and the source resonator are electrically isolated from each other.

3. The transmitter arrangement according to claim 1 or claim 2, wherein the amplifier resonator is electrically isolated from an inverter or a power source.

4. The transmitter arrangement according to any one of claims 1 to 3, wherein the source resonator has an inductor-capacitor-capacitor (LCC) compensation topology.

5. The transmitter arrangement according to claim 4, wherein the source resonator comprises: a first capacitor connected in series with the planar source coil; a second capacitor connected in parallel with the planar source coil and the first capacitor; andan inductor connected in scries with an arrangement comprising the planar source coil, the first capacitor and the second capacitor.

6. The transmitter arrangement according to any one of claims 1 to 5, wherein the amplifier resonator has a series-series (SS) compensation topology.

7. The transmitter arrangement according to claim 6, wherein the amplifier resonator comprises a capacitor connected in series with the amplifier coil.

8. The transmitter arrangement according to any one of claims 1 to 7, wherein the planar source coil is compensated at the resonant system angular frequency.

9. The transmitter arrangement according to any one of claims 1 to 8, wherein the amplifier coil is compensated at above the resonant system angular frequency.

10. The transmitter arrangement according to any one of claims 1 to 9, wherein the amplifier coil is a planar amplifier coil; and wherein the planar amplifier coil surrounds the planar source coil.

11. The transmitter arrangement according to any one of claims 1 to 9, wherein the amplifier coil is a conical amplifier coil; wherein the conical amplifier coil forms a curved side surface of a truncated cone; and wherein the planar source coil forms a truncated surface of the truncated cone or a base surface of the truncated cone.

12. A wireless power transfer system comprising: a transmitter arrangement according to any one of claims 1 to 11; and a receiver resonator configured to be wirelessly coupled to the transmitter arrangement, the receiver resonator comprising a receiver coil.

13. The wireless power transfer system according to claim 12, wherein the receiver coil is a planar receiver coil; and wherein the receiver coil is parallel to and spaced apart from the planar- source coil.

14. The wireless power transfer system according to claim 12 or claim 13, wherein the receiver resonator has an inductor-capacitor-capacitor (LCC) compensation topology.

15. The wireless power transfer system according to claim 14, wherein the receiver resonator comprises: a first capacitor connected in series with the receiver coil; a second capacitor connected in parallel with the receiver coil and the first capacitor; and an inductor connected in series with an arrangement comprising the receiver coil, the first capacitor and the second capacitor.

16. A method of forming a transmitter arrangement, the method comprising: providing a source resonator configured to be connected to an alternating (AC) voltage source, the source resonator comprising a planar source coil; and coupling an amplifier resonator to the source resonator wirelessly, the amplifier resonator comprising an amplifier coil;wherein the transmitter arrangement is configured such that a resonant angular frequency of the amplifier resonator is greater than a resonant system angular frequency of the source resonator to increase an output power and extend a power transfer distance.

17. The method according to claim 16, wherein the amplifier resonator and the source resonator are electrically isolated from each other.

18. The method according to claim 16 or claim 17, wherein the amplifier resonator is electrically isolated from an inverter or a power source.

19. The method according to any one of claims 16 to 18, wherein the source resonator has an inductor-capacitor-capacitor (LCC) compensation topology.

20. The method according to claim 19, wherein the source resonator comprises: a first capacitor connected in series with the planar source coil; a second capacitor connected in parallel with the planar source coil and the first capacitor; and an inductor connected in series with an arrangement comprising the planar source coil, the first capacitor and the second capacitor.

21. The method according to any one of claims 16 to 20, wherein the amplifier resonator has a series-series (SS) compensation topology.

22. The method according to claim 21, wherein the amplifier resonator comprises a capacitor connected in series with the amplifier coil.

23. The method according to any one of claims 16 to 22, wherein the planar source coil is compensated at the resonant system angular frequency.

24. The method according to any one of claims 16 to 23, wherein the amplifier coil is compensated at above the resonant system angular frequency.

25. The method according to any one of claims 16 to 24, wherein the amplifier coil is a planar amplifier coil; and wherein the planar amplifier coil surrounds the planar source coil.

26. The method according to any one of claims 16 to 24, wherein the amplifier coil is a conical amplifier coil; wherein the conical amplifier coil forms a curved side surface of a truncated cone; and wherein the planar source coil forms a truncated surface of the truncated cone or a base surface of the truncated cone.

27. A method of forming a wireless power transfer system, the method comprising: providing a transmitter arrangement according to any one of claims 1 to 11; and coupling a receiver resonator to the transmitter arrangement wirelessly, the receiver resonator comprising a receiver coil.

28. The method according to claim 27, wherein the receiver coil is a planar receiver coil; and wherein the receiver coil is parallel to and spaced apart from the planar source coil.

29. The method according to claim 27 or claim 28, wherein the receiver resonator has an inductor-capacitor-capacitor (LCC) compensation topology.

30. The method according to claim 29, wherein the receiver resonator comprises: a first capacitor connected in series with the receiver coil; a second capacitor connected in parallel with the receiver coil and the first capacitor; and an inductor connected in series with an arrangement comprising the receiver coil, the first capacitor and the second capacitor.

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