WO2024096816A1

WO2024096816A1 - Device, receiver and system for facilitating wireless charging of vehicle

Info

Publication number: WO2024096816A1
Application number: PCT/SG2023/050708
Authority: WO
Inventors: Yew Choon Tan; Ching Eng PNG; Xianke GAO
Original assignee: Agency For Science, Technology And Research
Priority date: 2022-10-31
Filing date: 2023-10-23
Publication date: 2024-05-10

Abstract

A device for facilitating wireless charging of a vehicle is provided. The device comprises: a transmitter comprising: a transmitter coupling coil electrically connectable to a power source, and configured to receive electrical energy from the power source and transfer the electrical energy by a magnetic flux; and a receiver comprising: a receiver coupling coil placed adjacent to the transmitter coupling coil, configured to receive the electrical energy from the transmitter coupling coil by the magnetic flux, and electrically connectable to a load to charge a battery of the vehicle, wherein one of the transmitter coupling coil and the receiver coupling coil comprises a first polarized coil and a first non-polarized coil, and the other of the transmitter coupling coil and the receiver coupling coil comprises one of a second polarized coil and a second non-polarized coil.

Description

DEVICE, RECEIVER AND SYSTEM FOR FACILITATING WIRELESS

CHARGING OF VEHICLE

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This patent application claims the benefit of priority of Singapore Patent Application No. 10202251559W, filed on 31 October 2022, the contents of which being hereby incorporated by reference in its entirety for all purposes.

TECHNICAL FIELD

[0002] Various embodiments relate to a device, a receiver, and a system for facilitating wireless charging of a vehicle.

BACKGROUND

[0003] Due to development of vehicles, for example, electric vehicles (EV), wireless power transfer (WPT) technologies for wireless power charging of the electric vehicles (EV) have been developed. The wireless power transfer (WPT) technologies may fall into two categories as follows: a near-field technology and a far-field technology. In the near-field technology, power may be transferred over a short distance using inductive coupling between a transmitter coil and a receiver coil. Some commonly known near-field wireless power transfer (WPT) technologies may be an inductive wireless power transfer (WPT) technology and a magnetic resonance wireless power transfer (WPT) technology. The Inductive wireless power transfer (WPT) technology may be used for a very short-range power transfer over a distance which is not more than 40mm between the transmitter coil and the receiver coil. The magnetic resonance wireless power transfer (WPT) technology may be used for a close range power transfer over a distance which is not more than 300mm between the transmitter coil and the receiver coil. In the magnetic resonance wireless power transfer (WPT) technology, electrical energy may be transferred by resonating magnetic flux from the transmitter coil to the receiver coil through thin air. [0004] FIG. 1 is a block diagram illustrating a conventional system for wireless charging of a vehicle. As shown in FIG. 1, the conventional system may comprise a ground assembly (GA) which is a ground unit and a vehicle assembly (VA) which is mounted on the vehicle. The ground assembly (GA) may comprise a power grid connected a Power Factor Correction (PFC) converter, followed by a DC-AC inverter, a filter and resonant compensation network that is connected to the transmitter coil (also referred to as a “transmitter coupling coil”). The magnetic energy generated by the transmitter coil on the ground assembly (GA) may be coupled to a receiver coil (also referred to as a “receiver coupling coil”) on the vehicle assembly (VA). The vehicle assembly (VA) may comprise the receiver coil connecting to a resonant compensation network and filter, a rectifier, and an optional impedance converter that produces suitable voltages and currents to the connected vehicle battery to charge the vehicle battery. The design of the transmitter coil and the receiver coil may contribute towards a magnetic flux linkage and a coupling factor between the transmitter coil and the receiver coil, and thus affect power transfer characteristics.

[0005] For a system for wireless charging of the vehicle, the transmitter coil and the receiver coil are likely to be designed and installed separately by infrastructure authorities and automotive makers respectively. Therefore, to achieve high power transfer efficiency for the system and to minimise power loss for the wireless charging of the vehicle, there is a need to provide the transmitter coil and the receiver coil with the high interoperability.

SUMMARY

[0006] According to various embodiments, there is a device for facilitating wireless charging of a vehicle, comprising: a transmitter comprising: a transmitter coupling coil electrically connectable to a power source, and configured to receive electrical energy from the power source and transfer the electrical energy by a magnetic flux; and a receiver comprising: a receiver coupling coil placed adjacent to the transmitter coupling coil, configured to receive the electrical energy from the transmitter coupling coil by the magnetic flux, and electrically connectable to a load to charge a battery of the vehicle, wherein one of the transmitter coupling coil and the receiver coupling coil comprises a first polarized coil and a first non-polarized coil, and the other of the transmitter coupling coil and the receiver coupling coil comprises one of a second polarized coil and a second non-polarized coil. [0007] In some embodiments, the one of the transmitter coupling coil and the receiver coupling coil comprises a first ferrite core, and the first ferrite core has an I-shape including a stem, an upper part and a lower part, and each cross-sectional area of the upper part and the lower part is larger than a cross-sectional area of the stem.

[0008] In some embodiments, the first polarized coil comprises a solenoid coil winding around the stem of the first ferrite core, and the first non-polarized coil comprises a planar coil winding on the lower part of the first ferrite core.

[0009] In some embodiments, the other of the transmitter coupling coil and the receiver coupling coil comprises a second ferrite core, and the second ferrite core has a bar shape.

[0010] In some embodiments, the second polarized coil or the second non-polarized coil of the other of the transmitter coupling coil and the receiver coupling coil is placed on top of the second ferrite core.

[0011] In some embodiments, the one of the transmitter coupling coil and the receiver coupling coil comprises a first shield plate spaced apart from the first ferrite core, and the other of the transmitter coupling coil and the receiver coupling coil comprises a second shield plate spaced apart from the second ferrite core.

[0012] In some embodiments, the receiver coupling coil comprises the first polarized coil and the first non-polarized coil, the transmitter coupling coil comprises one of the second polarized coil and the second non-polarized coil, and the load comprises a first load connected to the first polarized coil and a second load connected to the first non-polarized coil.

[0013] In some embodiments, one of the transmitter and the receiver which comprises the one of the transmitter coupling coil and the receiver coupling coil comprises a first switch configured to switch between the first polarized coil and the first non-polarized coil based on whether the other of the transmitter coupling coil and the receiver coupling coil comprises the second polarized coil or the second non-polarized coil.

[0014] In some embodiments, the device further comprises: a sensor configured to determine a first current between the first polarized coil and the load and a second current between the first non-polarized coil and the load, and a controller configured to determine whether the other of the transmitter coupling coil and the receiver coupling coil comprises the second polarized coil or the second non-polarized coil based on the first current and the second current.

[0015] In some embodiments, the receiver coupling coil comprises the first polarized coil and the first non-polarized coil, the transmitter coupling coil comprises one of the second polarized coil and the second non-polarized coil, and the receiver comprises the first switch configured to switch between the first polarized coil and the first non-polarized coil to connect the load to one of the first polarized coil and the first non-polarized coil, based on whether the transmitter coupling coil comprises the second polarized coil or the second non-polarized coil.

[0016] In some embodiments, where it is determined that the transmitter coupling coil comprises the second polarized coil, the first switch is configured to switch to connect the load to the first polarized coil, and where it is determined that the transmitter coupling coil comprises the second non-polarized coil, the first switch is configured to switch to connect the load to the first non-polarized coil.

[0017] In some embodiments, the transmitter further comprises a transmitter connecting component electrically connectable to the power source and the transmitter coupling coil, the receiver further comprises a first receiver connecting component electrically connectable to the first polarized coil and the load, and a second receiver connecting component electrically connectable to the first non-polarized coil and the load, and the transmitter connecting component, the first receiver connecting component, and the second receiver connecting component are configured to create a magnetic resonance, to transfer the electrical energy from the transmitter coupling coil to the receiver coupling coil by the magnetic flux.

[0018] In some embodiments, the transmitter further comprises a first tuning circuit comprising a first tunable component and a first tuning switch, the receiver further comprises a second tuning circuit comprising a second tunable component and a second tuning switch, and the first tuning switch and the second tuning switch are configured to be activated based on at least one of a distance and alignment between the transmitter coupling coil and the receiver coupling coil, so that the first tunable component and the second tunable component shift the magnetic resonance.

[0019] In some embodiments, the other of the transmitter coupling coil and the receiver coupling coil comprises the second polarized coil comprising a solenoid coil winding.

[0020] According to various embodiments, there is a receiver mountable on a vehicle for facilitating wireless charging of the vehicle, comprising: a load electrically connectable to a battery of the vehicle; and a receiver coupling coil placed adjacent to a transmitter coupling coil of a ground assembly, configured to receive electrical energy from the transmitter coupling coil by a magnetic flux, and electrically connectable to the load to charge the battery of the vehicle, wherein the receiver coupling coil comprises a first polarized coil and a first nonpolarized coil. [0021] In some embodiments, the receiver further comprises: a first switch configured to switch between the first polarized coil and the first non-polarized coil to connect the load to one of the first polarized coil and the first non-polarized coil, based on whether the transmitter coupling coil comprises a second polarized coil or a second non-polarized coil.

[0022] According to various embodiments, there is a system for facilitating wireless charging of a vehicle, comprising: a ground assembly on a ground, comprising: a power grid; and a transmitter comprising a transmitter coupling coil electrically connectable to the power grid, and configured to receive electrical energy from the power grid and transfer the electrical energy by a magnetic flux; and a vehicle assembly mounted on the vehicle, comprising: a battery of the vehicle; a receiver comprising a receiver coupling coil placed adjacent to the transmitter coupling coil, configured to receive the electrical energy from the transmitter coupling coil by the magnetic flux, and electrically connectable to a load to charge the battery of the vehicle, wherein one of the transmitter coupling coil and the receiver coupling coil comprises a first polarized coil and a first non-polarized coil, and the other of the transmitter coupling coil and the receiver coupling coil comprises one of a second polarized coil and a second non-polarized coil.

[0023] In some embodiments, the one of the transmitter coupling coil and the receiver coupling coil comprises a first ferrite core, and the first polarized coil comprises a solenoid coil winding around a stem of the first ferrite core, and the first non-polarized coil comprises a planar coil winding on a lower part of the first ferrite core.

[0024] In some embodiments, the receiver coupling coil comprises the first polarized coil and the first non-polarized coil, the transmitter coupling coil comprises one of the second polarized coil and the second non-polarized coil, and the load comprises a first load connected to the first polarized coil and a second load connected to the first non-polarized coil.

[0025] In some embodiments, the receiver coupling coil comprises the first polarized coil and the first non-polarized coil, the transmitter coupling coil comprises one of the second polarized coil and the second non-polarized coil, and the receiver further comprises a first switch configured to switch between the first polarized coil and the first non-polarized coil to connect the load to one of the first polarized coil and the first non-polarized coil, based on whether the transmitter coupling coil comprises the second polarized coil or the second non-polarized coil.

BRIEF DESCRIPTION OF THE DRAWINGS [0026] In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments are described with reference to the following drawings, in which:

[0027] FIG. 1 is a block diagram illustrating a conventional system for wireless charging of a vehicle.

[0028] FIG. 2 is a circuit diagram illustrating a device for wireless charging of a vehicle according to various embodiments.

[0029] FIG. 3 is an exemplary diagram illustrating different types of a transmitter coupling coil on a ground assembly (GA) according to various embodiments.

[0030] FIG. 4 is an exemplary diagram illustrating an interoperable receiver coupling coil on a vehicle assembly (VA) according to various embodiments.

[0031] FIG. 5 is an exemplary diagram illustrating a transmitter coupling coil and an interoperable receiver coupling coil according to various embodiments.

[0032] FIG. 6 illustrates simulated input and output power waveforms for a polarized double- D transmitter coil as a transmitter coupling coil of a device of FIG. 2.

[0033] FIG. 7 illustrates plots of coil-to-coil power transfer characteristics for a polarized double-D transmitter coil as a transmitter coupling coil of a device of FIG. 2.

[0034] FIG. 8 illustrates simulated input and output power waveforms for a non-polarized planar transmitter coil as a transmitter coupling coil of a device of FIG. 2.

[0035] FIG. 9 illustrates plots of coil-to-coil power transfer characteristics for a non-polarized planar transmitter coil as a transmitter coupling coil of a device of FIG. 2.

[0036] FIG. 10 is a circuit diagram illustrating a device for wireless charging of a vehicle according to various embodiments.

[0037] FIG. 11 illustrates simulated input and output power waveforms for a polarized double- D transmitter coil as a transmitter coupling coil of a device of FIG. 10.

[0038] FIG. 12 illustrates simulated input and output power waveforms for a non-polarized planar transmitter coil as a transmitter coupling coil of a device of FIG. 10.

[0039] FIG. 13 illustrates plots of coil-to-coil power transfer characteristics for an interoperable receiver coupling coil against a transmitter coupling coil of a device of FIG. 10. [0040] FIG. 14 is an exemplary diagram illustrating a transmitter coupling coil and a receiver coupling coil according to various embodiments. [0041] FIG. 15 is a circuit diagram illustrating a device for wireless charging of a vehicle according to various embodiments.

[0042] FIG. 16 illustrates simulated input and output power waveforms taken across nodes of A-A’ and B-B’ of a device of FIG. 15.

[0043] FIG. 17 illustrates plots of coil-to-coil power transfer characteristics of a device of FIG.

15 at frequency ranging from 50kHz to 150kHz.

[0044] FIG. 18 illustrates a plot of a coupling factor k of coupling coils of a device of FIG. 15 at different separation gap (Z), and plots of coil-to-coil power transfer characteristics of the coupling coils of the device of FIG. 15 at the different separation gap (Z).

[0045] FIG. 19 illustrates plots of coil-to-coil power transfer characteristics of the device of FIG. 15 for different value of coupling factor k.

[0046] FIG. 20 is an exemplary diagram illustrating misalignment between a transmitter coupling coil and a receiver coupling coil according to various embodiments.

[0047] FIG. 21 illustrates plots of a coupling factor k between a transmitter coupling coil and a receiver coupling coil according to a distance and a direction of misalignment between the transmitter coupling coil and the receiver coupling coil.

[0048] FIG. 22 illustrates plots of the coil-to-coil power transfer characteristics of a transmitter coupling coil and a receiver coupling coil according to a distance and a direction of misalignment between the transmitter coupling coil and the receiver coupling coil.

[0049] FIG. 23 is a circuit diagram illustrating a device for wireless charging of a vehicle according to various embodiments.

[0050] FIG. 24 illustrates plots of optimized coil-to-coil power transfer characteristics for a transmitter coupling coil and a receiver coupling coil of the device of FIG. 23 misaligned in a fore and aft direction, and a comparison between original and optimized power transfer efficiency (with adaptive tuning) at an operating nominal frequency of 85kHz.

[0051] FIG. 25 illustrates plots of optimized coil-to-coil power transfer characteristics for a transmitter coupling coil and a receiver coupling coil of the device of FIG. 23 misaligned in a lateral direction, and a comparison between original and optimized power transfer efficiency (with adaptive tuning) at an operating nominal frequency of 85kHz.

DESCRIPTION [0052] Embodiments described below in context of the method are analogously valid for the server, and vice versa. Furthermore, it will be understood that the embodiments described below may be combined, for example, a part of one embodiment may be combined with a part of another embodiment.

[0053] It will be understood that any property described herein for a specific device may also hold for any device described herein. Furthermore, it will be understood that for any device described herein, not necessarily all the components described must be enclosed in the device, but only some (but not all) components may be enclosed.

[0054] It should be understood that the terms “on”, “over”, “top”, “bottom”, “down”, “side”, “back”, “left”, “right”, “front”, “lateral”, “side”, “up”, “down” etc., when used in the following description are used for convenience and to aid understanding of relative positions or directions, and not intended to limit the orientation of any device, structure or any part of any device or structure. In addition, the singular terms “a”, “an”, and “the” include plural references unless context clearly indicates otherwise. Similarly, the word “or” is intended to include “and” unless the context clearly indicates otherwise.

[0055] The term “coupled” (or “connected”) herein may be understood as electrically coupled or as mechanically coupled, for example attached or fixed, or just in contact without any fixation, and it will be understood that both direct coupling or indirect coupling (in other words: coupling without direct contact) may be provided.

[0056] In order that the invention may be readily understood and put into practical effect, various embodiments will now be described by way of examples and not limitations, and with reference to the figures.

[0057] Interoperable WPT Coupler Solution for EV Wireless Power Charging

[0058] FIG. 2 is a circuit diagram illustrating a device for wireless charging of a vehicle according to various embodiments. FIG. 3 is an exemplary diagram illustrating different types of a transmitter coupling coil on a ground assembly (GA) according to various embodiments, and FIG. 4 is an exemplary diagram illustrating an interoperable receiver coupling coil on a vehicle assembly (VA) according to various embodiments. FIG. 5 is an exemplary diagram illustrating the transmitter coupling coil and the interoperable receiver coupling coil according to various embodiments.

[0059] Various embodiments provide the device for facilitating the wireless charging of the vehicle. In some embodiments, the device may include an interoperable wireless power transfer (WPT) coupler for facilitating the wireless charging of an electric vehicle (EV). [0060] In some embodiments, the device may include, but is not limited to a transmitter Tx and a receiver Rx. In some embodiments, a vehicle assembly (VA) mounted on the vehicle may include, but is not limited to, the transmitter Tx. The vehicle assembly (VA) may be an on- vehicle equipment, for example, situated on the opposite side of the vehicle. In some embodiments, a ground assembly (GA) on a ground may include, but is not limited to the receiver Rx. A charging hardware, including the transmitter Tx, may be connected to a power grid.

[0061] In some embodiments, the transmitter Tx may include, but is not limited to, a transmitter coupling coil (also referred to as a “transmitter coil”). In some embodiments, the transmitter coupling coil may include at least one inductor (having inductance of L_Tx) and at least one resistor (having resistance of R_Tx). In some embodiments, the receiver Rx may include, but is not limited to, a receiver coupling coil (also referred to as a “receiver coil”). In some embodiments, the receiver coupling coil may include at least one inductor, for example, two inductors (having inductance of L_Rx_S and L_Rx_P), and at least one resistor, for example, two resistors (having resistance of R_Rx_S and R_Rx_P). As shown in FIG. 2, in some embodiments, the wireless power transfer (WPT) coupler (also referred to as a “coupler”) may include a part of the transmitter Tx, for example, the transmitter coupling coil, and a part of the receiver Rx, for example, the receiver coupling coil.

[0062] In some embodiments, the transmitter Tx may further include a power source, for example, an AC main source (also referred to as an “AC source”), for providing electrical energy to the transmitter coupling coil. For example, the AC main source may be electrically connected to the power grid and receive the electrical energy from the power grid. In some embodiments, the ground assembly (GA) may further include at least one of the power grid, a power-factor corrector (PFC) converter, a DC-AC inverter, a filter and resonant compensation network, and the AC main source. In some other embodiments, the power grid may be external to the vehicle assembly (VA).

[0063] In some embodiments, the transmitter coupling coil may be electrically connectable to the power source, for example, the AC main source. In some embodiments, the transmitter coupling coil may be connected to the power grid via one or more components. For example, the transmitter coupling coil may be connected to the power grid via the power-factor corrector (PFC) converter, the DC-AC inverter, the filter and resonant compensation network, and the AC main source. In some embodiments, the transmitter coupling coil may receive the electrical energy from the power grid, and transfer the electrical energy out to the receiver coupling coil by a magnetic flux.

[0064] In some embodiments, the receiver coupling coil may be placed adjacent to the transmitter coupling coil. In some embodiments, the receiver coupling coil may receive the electrical energy from the transmitter coupling coil by the magnetic flux. In some embodiments, the receiver Rx may further include a load which is electrically connectable to the battery of the vehicle. In some embodiments, the load may include at least one resistor (having resistance of R Load). In some embodiments, the receiver coupling coil may be electrically connectable to the load to charge the battery of the vehicle.

[0065] In some embodiments, the vehicle assembly (VA) may further include at least one of the load, a filter and resonant compensation network, a rectifier, and an impedance converter. In some embodiments, the receiver coupling coil may be connected to the battery of the vehicle via one or more components. For example, the receiver coupling coil may be connected to the battery of the vehicle via the load, the filter and resonant compensation network, the rectifier, and the impedance converter.

[0066] In some embodiments, one of the transmitter coupling coil and the receiver coupling coil may include a first polarized coil and a first non -polarized coil. In some embodiments, the other of the transmitter coupling coil and the receiver coupling coil may include one of a second polarized coil and a second non -polarized coil.

[0067] In some embodiments, as shown in FIG. 2, the receiver coupling coil may include the first polarized coil, for example, including an inductor (having inductance of L_Rx_S) and a resistor (having resistance of R_Rx_S), and the first non-polarized coil, for example, including an inductor (having inductance of L_Rx_P) and a resistor (having resistance of R_Rx_P). In some embodiments, as shown in FIG. 2, the transmitter coupling coil may include one of the second polarized coil and the second non-polarized coil, for example, including an inductor (having inductance of L_Tx) and a resistor (having resistance of R_Tx). In some embodiments, as shown in FIG. 2, the load may include a first load, for example, including a resistor (having resistance of R Loadl), connected to the first polarized coil and a second load, for example, including a resistor (having resistance of R_Load2), connected to the first non-polarized coil.

[0068] In some embodiments, as shown in FIG. 2, the transmitter Tx may further include a transmitter connecting component electrically connectable to the power source, for example, the AC main source, and the transmitter coupling coil. For example, the transmitter connecting component may include a transmitter connecting capacitor (having capacitance of C_Tx). In some embodiments, the receiver Rx may further include a first receiver connecting component electrically connectable to the first polarized coil and the load, for example, the first load, and a second receiver connecting component electrically connectable to the first non-polarized coil and the load, for example, the second load. For example, the first receiver connecting component may include a first receiver connecting capacitor (having capacitance of C_Rx_S), and the second receiver connecting component may include a second receiver connecting capacitor (having capacitance of C_Rx_P). In some embodiments, the transmitter connecting component, the first receiver connecting component, and the second receiver connecting component may create a magnetic resonance, to transfer the electrical energy from the transmitter coupling coil to the receiver coupling coil by the magnetic flux.

[0069] In some embodiments, the one of the transmitter coupling coil and the receiver coupling coil may include a first ferrite core. For example, as shown in FIG. 4, where the receiver coupling coil includes the first polarized coil and the first non-polarized coil, the receiver coupling coil may include the first ferrite core having an I-shape. Although not shown, as another example, where the transmitter coupling coil includes the first polarized coil and the first non-polarized coil, the transmitter coupling coil may include the first ferrite core having the I-shape.

[0070] In some embodiments, the first ferrite core may have the I-shape, including a stem, an upper part (also referred to as a “top part”) and a lower part (also referred to as a “bottom part”). For example, each cross-sectional area of the upper part and the lower part is larger than a cross-sectional area of the stem. In some embodiments, the first polarized coil may include a solenoid coil winding around the stem of the first ferrite core, and the first non-polarized coil may include a planar coil winding on the lower part of the first ferrite core. For example, as shown in FIG. 4, where the receiver coupling coil includes the first polarized coil and the first non-polarized coil, the first polarized coil of the receiver coupling coil may include a solenoid coil winding around the stem of the first ferrite core, and the first non-polarized coil of the receiver coupling coil may include a planar coil winding on the lower part of the first ferrite core. Although not shown, as another example, where the transmitter coupling coil includes the first polarized coil and the first non-polarized coil, the first polarized coil of the transmitter coupling coil may include a solenoid coil winding around the stem of the first ferrite core, and the first non-polarized coil of the transmitter coupling coil may include a planar coil winding on the lower part of the first ferrite core. [0071] In some embodiments, the other of the transmitter coupling coil and the receiver coupling coil may include a second ferrite core. In some embodiments, the second ferrite core may have a bar shape, and include a plurality of ferrite core bars. For example, as shown in FIG. 3(a), where the transmitter coupling coil includes the second polarized coil, for example, a double-D coil, the transmitter coupling coil may include the second ferrite core including a plurality of ferrite core bars. As another example, as shown in FIG. 3(b), where the transmitter coupling coil includes the second non-polarized coil, for example, a rectangular planar coil, the transmitter coupling coil may include the second ferrite core including a plurality of ferrite core bars. Although not shown, as another example, where the receiver coupling coil includes one of the second polarized coil and the second non-polarized coil, the receiver coupling coil may include the second ferrite core including a plurality of ferrite core bars.

[0072] In some embodiments, the second polarized coil or the second non-polarized coil of the other of the transmitter coupling coil and the receiver coupling coil may be placed on top of the second ferrite core. For example, as shown in FIG. 3(a), where the transmitter coupling coil includes the second polarized coil, for example, the double-D coil, the transmitter coupling coil may include the second ferrite core, and the second polarized coil of the transmitter coupling coil may be placed on top of the second ferrite core. As another example, as shown in FIG. 3(b), where the transmitter coupling coil includes the second non-polarized coil, for example, the rectangular planar coil, the transmitter coupling coil may include the second ferrite core, and the second non-polarized coil of the transmitter coupling coil may be placed on top of the second ferrite core. Although not shown, as another example, where the receiver coupling coil includes one of the second polarized coil and the second non-polarized coil, the receiver coupling coil may include the second ferrite core, and the second polarized coil or the second non-polarized coil of the receiver coupling coil may be placed on top of the second ferrite core. [0073] In some embodiments, the one of the transmitter coupling coil and the receiver coupling coil may include a first shield plate spaced apart from the first ferrite core. In some embodiments, the other of the transmitter coupling coil and the receiver coupling coil may include a second shield plate spaced apart from the second ferrite core. For example, as shown in FIG. 3, the transmitter coupling coil may include the second shield plate spaced apart from the second ferrite core. As another example, as shown in FIG. 4, the receiver coupling coil may include the first shield plate spaced apart from the first ferrite core.

[0074] In some embodiments, as shown in FIG. 3, coils may be broadly categorized into a polarized coil and a non-polarized coil. The non-polarized coil may be a flat planar coil which may generate a parallel magnetic flux. The planar coil may come in different shape forms, such as a square form, a rectangular form, and a circular form. The polarized coil may generate a perpendicular magnetic flux. The polarized coil may be in the form of at least one of a double- D coil, a bi-polar coil and a double D-quadrature coil.

[0075] As shown in FIG. 3, the coupler may include the transmitter coupling coil lying on top of the second ferrite core, for example, the plurality of ferrite core bars that are stacked above the second shield plate, for example, a metallic shield plate. As shown in FIG. 3(a), the transmitter coupling coil may include the second polarized coil, for example, a polarized double-D coil. Alternatively, as shown in FIG. 3(b), the transmitter coupling coil may include the second non-polarized coil, for example, a non-polarized rectangular planar coil. As shown in FIG. 3(a), In some embodiments, the polarized double-D coil may be made up of two rectangular planar coils (in an opposite winding direction) placing side by side and connecting in series, with 6 turns in each planar coil to give a total coil turns of 12. As shown in FIG. 3(b), In some embodiments, the non-polarized rectangular planar coil may be made up of flat coil winding with 10 turns.

[0076] In some embodiments, FIG. 4 depicts the interoperable receiver coupling coil which may demonstrate high interoperability towards the second polarized coil and the second nonpolarized coil of the transmitter coupling coil on the ground assembly (GA). In some embodiments, the receiver coupling coil may include the first polarized coil, for example, a 14- tums solenoid coil winding (labelled as Rx Solenoid Coil in FIG. 4) which may wrap around the stem of the I-shaped first ferrite core. In some embodiments, the receiver coupling coil may further include the first non-polarized coil, for example, a 10-tums rectangular planar coil winding (labelled as Rx Planar Coil in FIG. 4) on the lower (bottom) surface of the I-shaped first ferrite core. The Rx Solenoid Coil, may be a polarized coil, while the Rx Planar Coil may be a non-polarized coil. In some embodiments, the Rx Solenoid Coil and the Rx Planar Coil may be viewed as being separated and have no direct connection. In some embodiments, the first shield plate, for example, a metallic shield plate, may be placed above the I-shaped first ferrite core, having no physical contact with the first ferrite core and coil windings. The metallic shield plate may be used for shielding purposes to minimize a magnetic flux leakage between the transmitter coupling coil and the receiver coupling coil, and to minimize electromagnetic field radiation.

[0077] In some embodiments, as shown in FIG. 5, the second polarized coil of the transmitter coupling coil and the first polarized coil and the first non-polarized coil of the interoperable receiver coupling coil may be provided. For example, as shown in FIG. 5, the polarized double- D transmitter coil on the ground assembly (GA) and the interoperable receiver coil on the vehicle assembly (VA) may be provided. In some embodiments, the receiver coupling coil may be aligned to a center of the transmitter coupling coil, but raised vertically to a height level such that the receiver coupling coil on the vehicle assembly (VA) may be separated from the transmitter coupling coil on the ground assembly (GA) by a separation gap (Z). For example, as per the SAE J2954 Standard, there may be 3 classes of the separation gap (Z) as follows: Z1 at 100 to 150mm, Z2 at 140 to 210mm, and Z3 at 170 to 250mm. In some embodiments, the separation gap (Z) may be kept at the maximum of Z3 class at 250mm which may represent the worst-case scenarios as higher value of the separation gap (Z) may tend to associate with weaker coupling between the transmitter coupling coil on ground assembly (GA) and receiver coupling coil on the vehicle assembly (VA).

[0078] An equivalent circuit of the wireless power transfer (WPT) coupler shown in FIG. 5 is shown in FIG. 2. As shown in FIG. 2, parameters representing the wireless power transfer (WPT) coupler may include the following:

• L_Tx and R_Tx are self-inductance and AC -resistance of the transmitter coupling coil;

• L_Rx_S and R_Rx_S are self-inductance and AC-resistance of Rx Solenoid coil (first polarized coil);

• L_Rx_P and R_Rx_P are self-inductance and AC-resistance of Rx Planar coil (first non-polarized coil);

• The coupling between the transmitter coupling coil and the Rx Solenoid coil is represented by a coupling coefficient kl2;

• The coupling between the transmitter coupling coil and the Rx Planar coil is represented by a coupling coefficient kl 3 ; and

• The coupling within the receiver coupling coil, between the Rx Solenoid coil and the Rx Planar coil, is represented by a coupling coefficient k23.

For example, the above-mentioned parameters may be obtained through 3D Finite Element Method (FEM) electromagnetic simulation of the wireless power transfer (WPT) coupler shown in FIG. 5, using ANSYS Maxwell.

[0079] In some embodiments, to enhance power transfer over a longer distance range, magnetic resonance wireless power transfer (WPT) may require each coil in the wireless power transfer (WPT) coupler of FIG. 5 to be connected to its compensation circuitry. There may be different types of compensation circuit topologies, and a series-series (SS) resonant compensation topology may be one of the commonly used topologies due to its simplicity. FIG. 2 illustrates the series-series (SS) resonant compensation topology for the wireless power transfer (WPT) shown in FIG. 5. In some embodiments, the device may further include the transmitter connecting component, the first receiver connecting component, and the second receiver connecting component in series with the transmitter coupling coil, the first polarized coil, for example, the Rx Solenoid coil, and the first non-polarized coil, for example, the Rx Planar coil, respectively, to create the magnetic resonance at an operating nominal frequency. For example, the transmitter connecting component may include the transmitter connecting capacitor (having capacitance of C_Tx), the first receiver connecting component may include the first receiver connecting capacitor (having capacitance of C_Rx_S), and the second receiver connecting component may include the second receiver connecting capacitor (having capacitance of C_Rx_P). The capacitance values of the C_Tx, the C_Rx_S and the C_Rx_P may be calculated using mathematical equations (1), (2) and (3) as follows:

Capacitance Equation (l)

'

Capacitance ^Ecl^{uation 1}

'

Capacitance Equation ^)

'

where o is given by: co = 2K (operating nominal frequency) Equation (4)

As per the SAE J2954 standard, the operating nominal frequency for the wireless power charging for the electric vehicle (EV) using the magnetic resonance method is at 85kHz.

[0080] Electromagnetic Simulation of WPT Coupler

[0081] A 3D finite element method (FEM) electromagnetic simulation is used to evaluate performance characteristics of the interoperable receiver coupling coil shown in FIG. 4, using the ANSYS Maxwell. A computational model of two wireless power transfer (WPT) couplers are built in the ANSYS Maxwell environment: one coupler with the polarized double-D coil as shown in FIG. 3(a) as the transmitter coupling coil, and the other coupler with the non-polarized rectangular planar coil as shown in FIG. 3(b) as the transmitter coupling coil. In both wireless power transfer (WPT) coupler models, the coils may be aligned perfectly on a horizontal plane and separating at a vertical separation gap (Z) of 250mm. The setting of the material properties for the respective objects is shown in Table 1.

Table 1 : Material Properties

[0082] The simulation is set to run in Eddy Current solution type at the frequency of 85kHz which is the operating nominal frequency for the wireless charging of the electric vehicle (EV) as per the SAE J2954 standard. The simulated output data from the ANSYS Maxwell simulation that represents the characteristics of the transmitter coupling coil, the Rx Solenoid coil, and the Rx Planar coil in the two wireless power transfer (WPT) couplers described above, is shown in Table 2. As shown in the Table 2, the two wireless power transfer (WPT) couplers may have different transmitter coil characteristics. The polarized double-D coil has a self-inductance of 59.96pH and AC -resistance of 34.92mQ, while the non-polarized rectangular planar coil has a self-inductance of 99.63pH and AC -resistance of 99.63mQ. The interoperable receiver coils (i.e. the Rx Solenoid coil and the Rx Planar coil) present identical coil characteristics for both wireless power transfer (WPT) couplers. As shown in the Table 2, the polarized double-D transmitter coil shows a dominating coupling towards the Rx Solenoid coil (with kl2 at 0.1058) as compared to the Rx Planar coil (with kl3 at 0.0020). In the case of the non-polarized planar transmitter coil, the coupling towards the Rx Planar coil is higher (with kl3 at 0.0917) as compared to Rx Solenoid coil (with kl2 at -0.0013). As described above, coils of the same type (for example, polarized coil to polarized coil) are expected to couple better as compared to coils of different type (for example, polarized coil to nonpolarized coil). As shown in the Table 2, the coupling between the two receiver coupling coils (i.e. the Rx Solenoid coil and the Rx Planar coil) is low with k23 at 0.0049. This coupling may need to be kept low, so that minimum interference exists between the two receiver coupling coils.

[0083] With the simulated data as shown in the Table 2, the values of the various capacitors that form the respective compensation network for both the transmitter coupling coil and the receiver coupling coil in the wireless power transfer (WPT) coupler are calculated using the mathematical equations (1), (2) and (3). Table 3 shows the calculated capacitance values for C_Tx, C_Rx_S and C Rx P.

[0084] The above simulated and calculated data as shown in the Tables 2 and 3 are imported into an ANSYS Simplorer to model the circuit diagram shown in FIG. 2. The AC source shown in FIG. 2 is set to have a voltage amplitude of 240Vpeak, oscillating at 85kHz. The circuit simulation may aim to determine the followings:

• an input power transient waveform across a node A-A’;

• an output power transient waveform across a node B-B’ (the Rx_Solenoid coil);

• an output power transient waveform across a node C-C’ (the Rx_Planar coil);

• coil-to-coil power transfer efficiency between the transmitter coupling coil and the Rx Solenoid coil; and

• coil-to-coil power transfer efficiency between the transmitter coupling coil and the Rx Planar coil.

[0085] FIG. 6 illustrates simulated input and output power waveforms for a polarized double- D transmitter coil as a transmitter coupling coil of a device of FIG. 2. FIG. 7 illustrates plots of coil-to-coil power transfer characteristics for the polarized double-D transmitter coil as the transmitter coupling coil of the device of FIG. 2.

[0086] With reference to the circuit diagram shown in FIG. 2, FIG. 6(a) shows the simulated input power transient waveform taken across the node A-A’ for the polarized double-D coil as the transmitter coupling coil, along with the simulated output power waveform taken across the node B-B’ for the Rx_Solenoid coil and the node C-C’ for the Rx_Planar coil. For better illustration, a zoom-in on the respective power waveforms is shown in FIG. 6(b), for time between 450 ,sec to 500|j.sec. As shown in FIG. 6(b), the peak input power is at 12.43kW while the peak output power on the Rx Solenoid coil and the Rx Planar coil are at 12.04kW and 0.037kW respectively, indicating that power is mainly transferring wirelessly from the transmitter coupling coil to the Rx Solenoid coil with power loss of approximately 0.39kW. [0087] FIG. 7 shows the coil-to-coil power transfer efficiency characteristics at frequency ranging from 70kHz to 110kHz. At 85kHz, the coil-to-coil power transfer efficiency between the double-D transmitter coil and the Rx Solenoid coil is at 96%, while the coil-to-coil power transfer efficiency between the double-D transmitter coil and the Rx Planar coil is at 0.31%. This plot may further indicate that the power transfer may mainly take place between the double-D transmitter coil and the Rx Solenoid coil. In some embodiments, a term named bandwidth of the coil-to-coil power transfer characteristics may be defined. The bandwidth of the coil-to-coil power transfer characteristics may refer to a frequency range that has coil-to- coil power transfer efficiency maintaining at above 90%. As shown in FIG. 7, the bandwidth of the coil-to-coil power transfer characteristics for the Rx Solenoid coil is 7.8kHz (from 81.6kHz to 89.4kHz).

[0088] FIG. 8 illustrates simulated input and output power waveforms for a non-polarized planar transmitter coil as a transmitter coupling coil of a device of FIG. 2. FIG. 9 illustrates plots of coil-to-coil power transfer characteristics for a non-polarized planar transmitter coil as a transmitter coupling coil of a device of FIG. 2.

[0089] With reference to the circuit diagram shown in FIG. 2, FIG. 8(a) shows the simulated input power transient waveform taken across the node A-A’ for the non-polarized rectangular planar coil as the transmitter coupling coil, along with the simulated output power waveform taken across the node B-B’ for the Rx Solenoid coil and the node C-C’ for the Rx_Planar coil. For better illustration, a zoom-in on the respective power waveforms is shown in FIG. 8(b), for time between 450psec to 500 .sec. From the plot shown in FIG. 8(b), the peak input power is at 12.46kW, while the peak output power on the Rx Solenoid coil and the Rx Planar coil are at 0.037kW and 11.54kW respectively, indicating that the power may mainly be transferring wirelessly from the transmitter coupling coil to the Rx Planar coil with power loss of approximately 0.92kW. [0090] FIG. 9 shows the coil-to-coil power transfer efficiency characteristics at frequency ranging from 70kHz to 110kHz. At 85kHz, the coil-to-coil power transfer efficiency between the rectangular planar transmitter coil and the Rx Planar coil is at 96.49%, while the coil-to- coil power transfer efficiency between the rectangular planar transmitter coil and the Rx Solenoid coil is at 0.32%. This plot may further indicate that the power transfer may mainly take place between the transmitter coupling coil and the Rx Planar coil. The bandwidth of the coil-to-coil power transfer characteristics for the Rx Planar coil is 5.1kHz (from 82.9kHz to 88kHz).

[0091] FIG. 10 is a circuit diagram illustrating a device for wireless charging of a vehicle according to various embodiments.

[0092] In some embodiments, one of the transmitter coupling coil and the receiver coupling coil may include a first polarized coil and a first non -polarized coil. In some embodiments, the other of the transmitter coupling coil and the receiver coupling coil may include one of a second polarized coil and a second non -polarized coil.

[0093] In some embodiments, as shown in FIG. 10, the receiver coupling coil may include the first polarized coil, for example, including an inductor (having inductance of L_Rx_S) and a resistor (having resistance of R_Rx_S), and the first non-polarized coil, for example, including an inductor (having inductance of L_Rx_P) and a resistor (having resistance of R_Rx_P). In some embodiments, as shown in FIG. 10, the transmitter coupling coil may include one of the second polarized coil and the second non-polarized coil, for example, including an inductor (having inductance of L_Tx) and a resistor (having resistance of R_Tx). In some embodiments, as shown in FIG. 10, the load may include a resistor (having resistance of R Load) and may be electrically connectable to one of the first polarized coil and the first non-polarized coil.

[0094] In some embodiments, as shown in FIG. 10, the transmitter Tx may further include the transmitter connecting component electrically connectable to the power source, for example, the AC main source, and the transmitter coupling coil. For example, the transmitter connecting component may include the transmitter connecting capacitor (having capacitance of C_Tx). In some embodiments, the receiver Rx may further include the first receiver connecting component electrically connectable to the first polarized coil and the load, and the second receiver connecting component electrically connectable to the first non-polarized coil and the load. For example, the first receiver connecting component may include a first receiver connecting capacitor (having capacitance of C_Rx_S), and the second receiver connecting component may include a second receiver connecting capacitor (having capacitance of C_Rx_P). In some embodiments, the transmitter connecting component, the first receiver connecting component, and the second receiver connecting component may create the magnetic resonance, to transfer the electrical energy from the transmitter coupling coil to the receiver coupling coil by the magnetic flux.

[0095] In some embodiments, the one of the transmitter coupling coil and the receiver coupling coil may include a first ferrite core. For example, as shown in FIG. 10, where the receiver coupling coil includes the first polarized coil and the first non-polarized coil, the receiver coupling coil may include the first ferrite core having the I-shape. It may be appreciated that the first ferrite core described with reference to FIGS. 2 to 5 may be applied herein.

[0096] In some embodiments, the other of the transmitter coupling coil and the receiver coupling coil may include a second ferrite core. In some embodiments, the second ferrite core may have a bar shape, and include a plurality of ferrite core bars. For example, where the transmitter coupling coil includes the second polarized coil, for example, a double-D coil, the transmitter coupling coil may include the second ferrite core including a plurality of ferrite core bars. As another example, where the transmitter coupling coil includes the second nonpolarized coil, for example, a rectangular planar coil, the transmitter coupling coil may include the second ferrite core including a plurality of ferrite core bars. It may be appreciated that the second ferrite core described with reference to FIGS. 2 to 5 may be applied herein.

[0097] In some embodiments, one of the transmitter Tx and the receiver Rx which includes the one of the transmitter coupling coil and the receiver coupling coil may include a first switch S configured to switch between the first polarized coil and the first non-polarized coil based on whether the other of the transmitter coupling coil and the receiver coupling coil includes the second polarized coil or the second non-polarized coil. For example, as shown in FIG. 10, the receiver Rx may further include the first switch S configured to switch between the first polarized coil and the first non-polarized coil based on whether the transmitter coupling coil includes the second polarized coil or the second non-polarized coil. The first switch S may switch to connect the load to one of the first polarized coil and the first non-polarized coil of the receiver coupling coil. As shown in FIG. 10, where it is determined, for example, by a controller (not shown), that the transmitter coupling coil includes the second polarized coil, the first switch S may switch to connect the load to the first polarized coil of the receiver coupling coil, and where it is determined, for example, by the controller, that the transmitter coupling coil includes the second non-polarized coil, the first switch S may switch to connect the load to the first non-polarized coil of the receiver coupling coil. [0098] Although not shown, as another example, where the transmitter coupling coil includes the first polarized coil and the first non-polarized coil, the transmitter Tx may further include the first switch S configured to switch between the first polarized coil and the first nonpolarized coil of the transmitter coupling coil based on whether the receiver coupling coil includes the second polarized coil or the second non-polarized coil. Although not shown, the first switch S of the transmitter Tx may switch to connect the load to one of the first polarized coil and the first non-polarized coil of the transmitter coupling coil. Although not shown, where it is determined, for example, by the controller, that the receiver coupling coil includes the second polarized coil, the first switch S may switch to connect the load to the first polarized coil of the transmitter coupling coil, and where it is determined, for example, by the controller, that the receiver coupling coil includes the second non-polarized coil, the first switch S may switch to connect the load to the first non-polarized coil of the transmitter coupling coil.

[0099] In some embodiments, the first switch S may use a threshold voltage and/or a threshold current. In some embodiments, the first switch S may be in the form of a voltage or current controlled type which uses the threshold voltage/current to determine the switching state. In some embodiments, the device may further include a sensor (not shown) configured to determine a first current (first electric current) between the first polarized coil and the load and a second current (second electric current) between the first non-polarized coil and the load. For example, the sensor may determine the first electric current in a path between the first receiver connecting capacitor (having capacitance of C_Rx_S) and a first state (state 1) of the first switch S (i.e. the Rx Solenoid coil is in connection to the load), and determine the second electric current in a path between the second receiver connecting capacitor (having capacitance of C_Rx_P) and a second state (state 2) of the first switch S (i.e. the Rx Planar coil is connected to the load). As another example, the device may include a plurality of sensors, including a first sensor configured to determine the first electric current in the path between the first receiver connecting capacitor (having capacitance of C_Rx_S) and the first state (state 1) of the first switch S (i.e. the Rx Solenoid coil is in connection to the load), and a second sensor configured to determine the second electric current in the path between the second receiver connecting capacitor (having capacitance of C_Rx_P) and the second state (state 2) of the first switch S (i.e. the Rx Planar coil is connected to the load). In some embodiments, the device may further include the controller configured to determine whether the other of the transmitter coupling coil and the receiver coupling coil includes the second polarized coil or the second nonpolarized coil based on the first current and the second current. In some embodiments, the first switch S may then maintain a connection to the state that carries the higher current. For example, the controller may control the switching of the first switch S based on the first electric current and the second electric current determined by the sensor. In some embodiments, the device may include a switching system (not shown) which may include the first switch S, the sensor and the controller. In some embodiments, the sensor may include the controller.

[00100] As shown in the simulation results of FIGS. 6 to 9, depending on the type of transmitter coupling coil (for example, polarized coil or non-polarized coil), either the Rx Solenoid coil or the Rx Planar coil may be dominating in the power transfer. FIG. 10 shows a modified (revised) circuit diagram with the intention that either the Rx Solenoid coil or the Rx Planar coil will be connecting to the load. As shown in FIG. 10, the first switch S may be added on the receiver side to select between the Rx Solenoid coil or the Rx Planar coil. When the first switch S is in the first state (state 1), the Rx Solenoid coil may be in connection to the load, while when the first switch S is in the second state (state 2), the Rx Planar coil may be connected to the load.

[00101] FIG. 11 illustrates simulated input and output power waveforms for a polarized double-D transmitter coil as a transmitter coupling coil of a device of FIG. 10.

[00102] With reference to the revised circuit diagram (with the first switch S in the first state (state 1)) as shown in FIG. 10, FIG. 11(a) shows the simulated input power transient waveform taken across the node A-A’ for the polarized double-D coil as the transmitter coupling coil, along with the simulated output power waveform taken across the node B-B’ on the receiving end. For better illustration, a zoom-in on the respective power waveforms is shown in FIG. 11(b), for time between 450 ,sec to 500psec. From the plot shown in FIG. 11(b), the peak input power is at 12.45kW, while the peak output power at 11.96kW, with power loss of approximately 0.49kW.

[00103] FIG. 12 illustrates simulated input and output power waveforms for a non-polarized planar transmitter coil as a transmitter coupling coil of a device of FIG. 10.

[00104] With reference to the revised circuit diagram (with the first switch S in the second state (state 2)) as shown in FIG. 10, FIG. 12(a) shows the simulated input power transient waveform taken across the node A-A’ for the non-polarized rectangular planar coil as the transmitter coupling coil, along with the simulated output power waveform taken across the node B-B’ on the receiving end. For better illustration, a zoom-in on the respective power waveforms is shown in FIG. 12(b), for time between 450psec to 500psec. From the plot shown in FIG. 12(b), the peak input power is at 12.37kW, while the peak output power at 11.74kW, with power loss of approximately 0.63kW.

[00105] FIG. 13 illustrates plots of coil-to-coil power transfer characteristics for an interoperable receiver coupling coil against a transmitter coupling coil of a device of FIG. 10. [00106] FIG. 13 compares the coil-to-coil power transfer characteristics of the interoperable receiver coupling coil against the second polarized coil and the second non-polarized coil of the transmitter coupling coil, at the frequency ranging from 70kHz to 110kHz. With the second polarized coil as the transmitter coupling coil, the interoperable receiver coupling coil offers coil-to-coil power transfer characteristics with efficiency of 96.35% at 85kHz and bandwidth of 7.9kHz (from 81.6kHz to 89.5kHz). With the second non-polarized coil as the transmitter coupling coil, the interoperable receiver coupling coil offers coil-to-coil power transfer characteristics with efficiency of 96.8% at 85kHz and bandwidth of 5.2kHz (from 82.9kHz to 88.1kHz). The simulated results shown in FIGS. 11 to 13 may indicate that the receiver coupling coil solution shown in FIG. 3 along with the circuitry shown in FIG. 10 may demonstrate high interoperability against the second polarized coil and the second nonpolarized coil of the transmitter coupling coil, and offer high power transfer efficiency of more than 90%.

[00107] Coupling Coil Design and Compensation Topology

[00108] FIG. 14 is an exemplary diagram illustrating a transmitter coupling coil and a receiver coupling coil according to various embodiments.

[00109] In some embodiments, wireless power charging of the electric vehicle (EV) may be realized using the magnetic resonance wireless power transfer (WPT) technology, which may require a pair of coupling coils, one coil on the ground assembly (GA) and the other coil on the vehicle assembly (VA), to transfer the electrical energy from ground assembly (GA) to the vehicle assembly (VA).

[00110] To enhance the power transfer over a longer distance range, in some embodiments, the magnetic resonance wireless power transfer (WPT) technology may also require each coil in the coupling coils to be connected to a compensation circuitry. There may be different types of compensation circuit topologies available, and a series-series (SS) resonant compensation topology may be one of the commonly used topology due to its simplicity. FIGS. 14(a) and 14(b) show exemplary diagrams of the coil design for the transmitting ground assembly (GA). In some embodiments, each of the transmitter coupling coil and the receiver coupling coil may include a solenoid coil winding around the ferrite core, and each of the transmitter coupling coil and the receiver coupling coil may include a shield plate spaced apart from the ferrite core. Although not shown, in some embodiments, the ferrite core may have an I-shape, a circular shape or a donut shape.

[00111] As shown in FIGS. 14(a) and 14(b), in some embodiments, the transmitter coupling coil may include 3 parallel connected solenoid coils wrapping around an I-shaped ferrite core. The transmitter coupling coil may further include a metallic shield plate, located under the ferrite core, while having no physical contact with the ferrite core and solenoid coils. The metallic shield plate may be used for shielding purposes to minimize the leakage magnetic flux between the coupling coils and to minimize the electromagnetic field radiation. FIG. 14(c) shows exemplary diagrams of the coil design for the receiving vehicle assembly (VA) (for better illustration, the shield plate above the receiver coupling coil is not shown in FIG. 14(c)). As shown in FIG. 14(c), in some embodiments, the receiver coupling coil may be identical to, and be a mirror image of the transmitter coupling coil for the ground assembly (GA). The two coils (i.e. the transmitter coupling coil and the receiver coupling coil) may be separated by a vertical separation gap (Z), representing the gap between the ground assembly (GA) on the ground and vehicle assembly (VA) on the vehicle.

[00112] FIG. 15 is a circuit diagram illustrating a device for wireless charging of a vehicle according to various embodiments.

[00113] FIG. 15 illustrates the series-series (SS) resonant compensation topology used here for the magnetic resonance wireless power transfer (WPT) technology. In some embodiments, the device may further include a transmitter connecting component, for example, a transmitter connecting capacitor (having capacitance of C_GA), and a receiver connecting capacitor, for example, a receiver connecting capacitor (having capacitance of C_VA), in series with the transmitter coupling coil and the receiver coupling coil respectively, to create the magnetic resonance at the operating nominal frequency. The capacitance values of C_GA and C_VA may be calculated using mathematical equations (5) and (6) as follows:

Capacitance Equation (5)

Capacitance Equation (6)

where Li and L2 are self-inductance of the transmitter coupling coil and the receiver coupling coil respectively, and co is given by: co = 2TC (operating nominal frequency) Equation (7) As shown in FIG. 15, the equivalent circuit of the coupling coils may include a self-inductance Li and a coil-resistance Rl of the transmitter coupling coil and a self-inductance L2 and a coilresistance R2 of the receiver coupling coil. A mutual -inductance L_m may exist between the coupling coils, which may define a coupling factor k between the coupling coils as per a mathematical equation (8). The coupling factor value may range from 0 to 1, and it may contribute towards defining the coil-to-coil power transfer efficiency characteristics.

Coupling factor, k = Equation (8)

VG G

In the circuit as shown in FIG. 15, a transmitter end may be connected to an AC main source, while a receiver end may be connected to an equivalent load, for example, including a resistor (having resistance of R Load). For the maximum power transfer, the circuit may need to be balanced and R Load may be calculated using a mathematical equation (9) as follows:

R Load Equation (9)

[00114] Electromagnetic Simulation of Aligned Coupling Coils

[00115] An electromagnetic simulation is carried out using the ANSYS Maxwell and the ANSYS Simplorer, on the transmitter coupling coil and the receiver coupling coil shown in FIG. 14(c). A computational model of the transmitter coupling coil and the receiver coupling coil are built in the ANSYS Maxwell environment with the coupling coils aligned perfectly on a horizontal plane and separating at a vertical separation gap (Z) of 250mm. The setting of material properties for the respective objects is shown in Table 4.

Table 4: Material Properties

The simulation is set to run in Eddy Current solution type at the frequency of 85kHz which is the operating nominal frequency for wireless charging of the electric vehicle (EV) as per the SAE J2954 standard. The available output data from the ANSYS Maxwell simulation that is of interest is as listed below:

• Self-inductance of the transmitter coupling coil, Li;

• Resistance of the transmitter coupling coil, Ri;

• Self-inductance of the receiver coupling coil, L2;

• Resistance of the receiver coupling coil, R2; • Mutual inductance between the transmitter coupling coil and the receiver coupling coil, L_m; and

• Coupling factor, k

These output data may be imported into the ANSYS Simplorer to build the circuit as shown in FIG. 15. The AC main source as shown in FIG. 15 is set to have a voltage amplitude of 240Vpeak, oscillating at 85kHz. The capacitance of the transmitter connecting capacitor C_GA and the capacitance of the receiver connecting capacitor C_VA are calculated using the mathematical equations (5) and (6), along with the output data of Li and L2 at the operating nominal frequency of 85kHz. The resistance of the load R Load is calculated using the mathematical equation (9), along with the output data of L_m, Ri and R2 at the operating nominal frequency of 85kHz. The circuit simulation is conducted to determine the followings:

• Coil-to-coil power transfer characteristics; and

• Input power and output power transient waveform taken across nodes of A-A’ and B- B’ shown in FIG. 15 respectively.

[00116] FIG. 16 illustrates simulated input and output power waveforms taken across nodes of A-A’ and B-B’ of a device of FIG. 15.

[00117] FIG. 16(a) shows the simulated input and output power waveform (in transient) taken across the nodes of A-A’ and B-B’ in FIG. 15, respectively. For better illustration, a zoom-in of the same power waveform is shown in FIG. 16(b), for time between 450psec to 500psec. As shown in the plot in FIG. 16(b), the peak input and output power is at 11.892kW and 11.804kW respectively, indicating a coil-to-coil power transfer loss of 88W.

[00118] FIG. 17 illustrates plots of coil-to-coil power transfer characteristics of a device of FIG. 15 at frequency ranging from 50kHz to 150kHz.

[00119] As shown in FIG. 17, at 85kHz, the coil-to-coil power transfer efficiency is at 99%. In some embodiments, a term named bandwidth of the coil-to-coil power transfer characteristics may be defined. The bandwidth of the coil-to-coil power transfer characteristics may refer to the frequency range that has power transfer efficiency maintained above a defined margin. Considering using the 95% power efficiency mark as the margin, the coil-to-coil power transfer characteristics in FIG. 17 may have a bandwidth of 16.7kHz (from 78.8kHz to 95.5kHz).

[00120] Evaluation on Coupling factor k [00121] FIG. 18 illustrates a plot of a coupling factor k of coupling coils of a device of FIG. 15 at different separation gap (Z), and plots of coil-to-coil power transfer characteristics of the coupling coils of the device of FIG. 15 at the different separation gap (Z).

[00122] There may be three different Z-classes defined to classify the wireless power transfer (WPT) systems based on the expected maximum ground clearance. The three classes may be Z1 at 100mm to 150mm, Z2 at 140mm to 210mm, and Z3 at 170mm to 250mm. In FIG. 18, the change in the coupling factor k and the coil-to-coil power transfer characteristics of the coupling coils design shown in FIG. 14(c) may be evaluated, as the separation gap (Z) between the coupling coils changes between 100mm to 250mm at an interval of 50mm, while maintaining the two coupling coils in perfect alignment on the horizontal plane.

[00123] FIG. 18(a) presents a plot of the coupling factor k of the coupling coils at a different separation gap (Z). The coupling factor k of the coupling coils may tend to decrease from 0.62 to 0.28 as the separation gap (Z) between the transmitter coupling coil and the receiver coupling coil increases from 100mm to 250m. FIG. 18(b) shows plots of the coil-to-coil power transfer characteristics of the coupling coils at a different separation gap (Z) of 100mm, 150mm, 200mm and 250mm. Table 5 records the coil-to-coil power transfer efficiency at 85kHz as well as the bandwidth (using 95% power efficiency as a margin) of the power transfer characteristics as per the plots present in FIG. 18(b). As shown in the Table 5, the power transfer efficiency of the coupling coils with the separation gap (Z) of 100mm is at 99.6%. This power transfer efficiency may reduce linearly at 0.2% per 50mm increase in the separation gap (Z). The coil- to-coil power transfer characteristics may offer a wide bandwidth of 53.1kHz at the separation gap (Z) of 100mm, as compared to the bandwidth of 16.7kHz at the separation gap (Z) of 250mm.

Table 5: Summary of coupling coils at different separation gap (Z)

[00124] In some embodiments, to further evaluate the influence of the coupling factor k on the power transfer characteristics of the coupling coils, the circuit simulation set-up for the coupling coils with the separation gap (Z) of 250mm is used. The simulated output data extracted from the ANSYS Maxwell for the coupling coils with the separation gap (Z) of 250mm, along with the calculated capacitance of the transmitter connecting capacitor C_GA and the calculated capacitance of the receiver connecting capacitor C_VA and the resistance of R Load, as listed below may be imported into the circuit shown in FIG. 15:

• Self-inductance and resistance of the transmitter coupling coil, Li = 31.99 H and Ri = 15.85mQ;

• Self-inductance and resistance of the receiver coupling coil, L2 = 32 H and R2 = 15.85mQ;

• Mutual inductance between the transmitter coupling coil and the receiver coupling coil, L_m = 8.98|j.H;

• Capacitance of the transmitter connecting capacitor C_GA = 109.58nF;

• Capacitance of the receiver connecting capacitor C_VA = 109.56nF; and

• Resistance of the load R Load = 4.8Q.

[00125] FIG. 19 illustrates plots of coil-to-coil power transfer characteristics of the device of FIG. 15 for different value of coupling factor k.

[00126] The coupling factor k may be varied from 0.05 to 0.25 at an interval of 0.05, to evaluate the change in the power transfer characteristics of the coupling coils. In some embodiments, since the value of the self-inductance of the transmitter coupling coil and of the receiver coupling coil (Li and L2) and the capacitance of the transmitter connecting capacitor and the receiver connecting capacitor (C_GA and C_VA) in the series-series (SS) resonant compensation network stays constant, the resonance may remain at the point of 85kHz, as shown in the various plots of FIG. 19. As per the observation shown in FIG. 19, the bandwidth of the power transfer characteristics may get narrower as the value of the coupling factor k reduces. Further reduction in the coupling factor k may eventually cause the power transfer efficiency at 85kHz to drop below the 95% margin, as in the case of k=0.05. Therefore, it may be necessary to have a reasonable coupling factor k of 0.25 or more, between the transmitter coupling coil and the receiver coupling coil, to achieve the coil-to-coil power transfer characteristics with reasonably wide bandwidth and power transfer efficiency of more than 95%. Table 6 summaries the power efficiency at 85kHz and bandwidth of the power transfer characteristics of FIG. 19.

Table 6: Coupling factor k influence on power transfer characteristics

[00127] Coil Misalignment and Adaptive Tuning

[00128] FIG. 20 is an exemplary diagram illustrating misalignment between a transmitter coupling coil and a receiver coupling coil according to various embodiments.

[00129] In the electric vehicle (EV) wireless power charging application, misalignment between the transmitter coupling coil and the receiver coupling coil on the horizontal plane is likely to be very common. Similar to the separation gap (Z) between the coupling coils, coil misalignment may result in low coupling factor k between the coupling coils and narrowing the bandwidth of the coil-to-coil power transfer characteristics. In FIG. 20, performance characteristics of the coupling coils shown in FIG. 14(c) may be evaluated, when subjecting to horizontal misalignment between the transmitter coupling coil (on the ground assembly (GA)) and the receiver coupling coil (on the vehicle assembly (VA)), in the fore and aft (vehicle’s front and back) and lateral (vehicle’s left and right) direction as illustrated in FIG. 20:

• FIG. 20(a) shows the coupling coils’ fore and aft and lateral direction in 3D view;

• FIG. 20(b) shows a plan view of the coupling coils’ misalignment in the fore and aft direction; and

• FIG. 20(c) shows a plan view of the coupling coils’ misalignment in the lateral direction.

This evaluation of the coil misalignment between the transmitter coupling coil (on the ground assembly (GA)) and the receiver coupling coil (on the vehicle assembly (VA)) is carried out for different slide distance ranging from 100mm to 500mm in the fore and aft direction as shown in FIG. 20(b), and from 100mm to 300mm in the lateral direction as shown in FIG. 20(c).

[00130] FIG. 21 illustrates plots of a coupling factor k between a transmitter coupling coil and a receiver coupling coil according to a distance and a direction of misalignment between the transmitter coupling coil and the receiver coupling coil.

[00131] FIG. 21 presents the plots of the coupling factor k between the transmitter coupling coil (on the ground assembly (GA)) and the receiver coupling coil (on the vehicle assembly (VA)) when subjects to the coil misalignment in the fore and aft direction (with slide distance from 100mm to 500mm at an interval of 100mm) and the lateral direction (with slide distance from 100mm to 300mm at an interval of 100mm). As shown in FIG. 21, the coupling factor k may decline as the misaligned slide distance increases. As shown in FIG. 21, the decline in the coupling factor k may be steepest in the case of misalignment in the lateral direction as compared to that in the fore and aft direction. As described above, the decline in the coupling factor k may result in narrowing the bandwidth of the coil-to-coil power transfer characteristics and lowering the power transfer efficiency at the operating nominal frequency.

[00132] FIG. 22 illustrates plots of the coil-to-coil power transfer characteristics of a transmitter coupling coil and a receiver coupling coil according to a distance and a direction of misalignment between the transmitter coupling coil and the receiver coupling coil.

[00133] FIG. 22(a) presents the plots of the coil-to-coil power transfer characteristics of the coupling coils shown in FIG. 20(a) when subject to coil misalignment in the fore and aft direction, with slide distance from 100mm to 500mm at an interval of 100mm. Three significant findings may be observed as the slide distance increases:

• Bandwidth of the coil-to-coil power transfer characteristics gets narrower, and it is becoming very significant in the case of slide distance at 500mm.

• The resonance is shifting away from the operating nominal frequency (85kHz), towards higher frequency, especially in the case of slide distance at 400mm and 500mm.

• Power transfer efficiency at 85kHz maintains above 95% for misaligned slide distance of up to 300mm. As the misaligned slide distance increases further to 400mm, the power transfer efficiency drops to 90.5% and eventually to 65% as the misaligned slide distance reaches 500mm. This significant drop in the power transfer efficiency especially in the case of slide distance at 500mm is due to the bandwidth narrowing and resonance shifting.

[00134] FIG. 22(b) presents the plots of the coil-to-coil power transfer characteristics of the coupling coils when subject to coil misalignment in the lateral direction, with slide distance from 100mm to 300mm at an interval of 100mm. Three significant findings may be observed as the slide distance increases:

• Bandwidth of the coil-to-coil power transfer characteristics gets narrower, and it is becoming very significant in the case of slide distance at 300mm.

• The resonance is shifting away from the operating nominal frequency (85kHz), towards higher frequency, especially in the case of slide distance at 200mm and 300mm.

• Power transfer efficiency at 85kHz maintains above 95% for misaligned slide distance of up to 100mm. As the misaligned slide distance increases further to 200mm, the power transfer efficiency drops to 94.3% and eventually to 16.8% as the misaligned slide distance reaches 300mm. This significant drop in the power transfer efficiency especially in the case of slide distance at 300mm is due to the bandwidth narrowing and resonance shifting.

[00135] From the results shown in FIGS. 21 and 22, the design of the transmitter coupling coil (on the ground assembly (GA)) and the receiver coupling coil (on the vehicle assembly (VA)) may show a better control in the coupling factor k and the power transfer characteristics for misalignment in the fore and aft direction as compared to the lateral direction. This coupling coils design may maintain the coil-to-coil power transfer efficiency at above 95% for coil misalignment of up to 300mm in the fore and aft direction and <200mm in the lateral direction. [00136] FIG. 23 is a circuit diagram illustrating a device for wireless charging of a vehicle according to various embodiments. In some embodiments, a first tuning circuit and a second tuning circuit which will be described with reference to FIG. 23 may be combined with any device of the various embodiments (for example, any device described with reference to FIGS. 2, 10 and/or 15).

[00137] As described with reference to FIG. 22, resonance shifting out of the operating nominal frequency (85kHz) may be seen taking place when the transmitter coupling coil (on the ground assembly (GA)) and the receiver coupling coil (on the vehicle assembly (VA)) are misaligned with:

• Slide distance at 400mm and 500mm in fore & aft direction; and

• Slide distance at 200mm and 300mm in lateral direction.

This shift in the resonance may result in significant decline in the power transfer efficiency at the operating nominal frequency.

[00138] In some embodiments, the device may provide an adaptive tuning technique to shift the resonance back to the operating nominal frequency. The adaptive tuning technique is a technique that may tune/change an overall impedance value in a matching or resonant network, by using one or more tunable components or switches to include additional discrete components into existing network, with the intention to shift the resonance in place to maintain the bandwidth coverage over the required operating frequency or frequency range. FIG. 23 shows a modified series-series (SS) resonant compensation network, to include additional switches and capacitors for the adaptive tuning. In some embodiments, as shown in FIG. 23, the transmitter Tx may further include the first tuning circuit including a first tunable component, for example, a first tunable capacitor (having capacitance of C GA Tune), and a first tuning switch S 1. In some embodiments, as shown in FIG. 23, the receiver Rx may include the second tuning circuit including a second tunable component, for example, a second tunable capacitor (having capacitance of C VA Tune) and a second tuning switch S2. In some embodiments, the first tuning switch SI and the second tuning switch S2 may be activated based on at least one of a distance and alignment between the transmitter coupling coil and the receiver coupling coil, so that the first tunable capacitor and the second tunable capacitor shift the magnetic resonance back to the operating nominal frequency.

[00139] FIG. 24 illustrates plots of optimized coil-to-coil power transfer characteristics for a transmitter coupling coil and a receiver coupling coil of the device of FIG. 23 misaligned in a fore and aft direction, and a comparison between original and optimized power transfer efficiency (with adaptive tuning) at an operating nominal frequency of 85kHz.

[00140] FIG. 24(a) presents the optimized coil-to-coil power transfer characteristics for the misaligned transmitter coupling coil (on the ground assembly (GA)) and receiver coupling coil (on the vehicle assembly (VA)) in the fore and aft direction. In the case of slide distance from 100mm to 300mm, the first tunable capacitor and the second tunable capacitor may be left out (with the first and second tuning switches SI, S2 in an open position) from the series-series (SS) resonant compensation network (in FIG. 23), since the bandwidth of the respective power transfer characteristics may be sufficient to cover the operating nominal frequency of 85kHz. For slide distance at 400mm and 500mm, the first and second tuning switches SI, S2 may be closed to include the first tunable capacitor and the second tunable capacitor in the network. This may help to shift the resonance back to the operating nominal frequency, as shown in FIG. 24(a).

[00141] FIG. 24(b) presents a comparison between the original power transfer efficiency (as shown in FIG. 15) and optimized power transfer efficiency (with adaptive tuning) at the operating nominal frequency of 85kHz. With the adaptive tuning, the power transfer efficiency may improve from 91% to 98% at misaligned slide distance of 400mm, and from 65% to 96% at misaligned slide distance of 500mm.

[00142] FIG. 25 illustrates plots of optimized coil-to-coil power transfer characteristics for a transmitter coupling coil and a receiver coupling coil of the device of FIG. 23 misaligned in a lateral direction, and a comparison between original and optimized power transfer efficiency (with adaptive tuning) at an operating nominal frequency of 85kHz.

[00143] FIG. 25 presents the optimized coil-to-coil power transfer characteristics for misaligned transmitter (on GA) and receiver (on VA) coils in the fore and aft direction. In the case of slide distance up to 150mm, the first tunable capacitor and the second tunable capacitor may be left out (with the first and second tuning switches SI, S2 in the open position) from the series-series (SS) resonant compensation network (in FIG. 23), since the bandwidth of the respective power transfer characteristics may be sufficient to cover the operating nominal frequency of 85kHz. For slide distance above 150mm, the first and second tuning switches SI, S2 may be closed to include the first tunable capacitor and the second tunable capacitor in the network. This may help to shift the resonance back to the operating nominal frequency, as shown in FIG. 25(a).

[00144] FIG. 25(b) presents a comparison between the original power transfer efficiency (as shown in FIG. 15) and optimized power transfer efficiency (with adaptive tuning) at the operating nominal frequency of 85kHz. With the adaptive tuning, the power transfer efficiency may improve from 94% to 98% at misaligned slide distance of 200mm, and from 17% to 86% at misaligned slide distance of 300mm.

[00145] As described above, the various embodiments may provide a device with an interoperable receiver coil solution for the vehicle assembly (VA) in the electric vehicle (EV) wireless power charging (WPC) system. In some embodiments, the device may include the receiver including the receiver coupling coil having two separated coils: one polarized solenoid coil winding that wraps around the ferrite core, and one non-polarized rectangular planar coil winding on the bottom surface of the ferrite core. Advantageously, the device may demonstrate high interoperability against the polarized coil, for example, the polarized transmitter coil, and the non-polarized coil, for example, the non-polarized transmitter coil, and may offer high power transfer efficiency of more than 90%. Although not shown, the two separated coils may be applied to the transmitter including the transmitter coupling coil on the ground assembly (GA).

[00146] In addition, as described above, the various embodiments may provide a coupling coils design (the transmitter coupling coil on the ground assembly (GA) and the receiver coupling coil on the vehicle assembly (VA)) and a modified resonant compensation network with the adaptive tuning. The coupling coils design may have a good coupling factor, offering good coil-to-coil power transfer characteristics with wide bandwidth for coils with large vertical separation gap (Z) and coil misalignment on the horizontal plane. The adaptive tuning technique introduced in the resonant compensation network may allow resonance tuning, to recover shifted resonance back to its operating nominal frequency. Simulation results of the wireless power transfer solution may show the coil-to-coil power transfer efficiency of more than 95% for coil misalignment up to 500mm in the fore and aft direction, and more than 85% for coil misalignment up to 300mm in the lateral direction.

[00147] While embodiments of the invention have been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced. It will be appreciated that common numerals, used in the relevant drawings, refer to components that serve a similar or the same purpose. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof’ include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof’ may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words “module,” “mechanism,” “element,” “device,” and the like may not be a substitute for the word “means.” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for.”

Claims

1. A device for facilitating wireless charging of a vehicle, comprising: a transmitter comprising: a transmitter coupling coil electrically connectable to a power source, and configured to receive electrical energy from the power source and transfer the electrical energy by a magnetic flux; and a receiver comprising: a receiver coupling coil placed adjacent to the transmitter coupling coil, configured to receive the electrical energy from the transmitter coupling coil by the magnetic flux, and electrically connectable to a load to charge a battery of the vehicle, wherein one of the transmitter coupling coil and the receiver coupling coil comprises a first polarized coil and a first non-polarized coil, and the other of the transmitter coupling coil and the receiver coupling coil comprises one of a second polarized coil and a second non-polarized coil.

2. The device according to claim 1, wherein the one of the transmitter coupling coil and the receiver coupling coil comprises a first ferrite core, and the first ferrite core has an I-shape including a stem, an upper part and a lower part, and each cross-sectional area of the upper part and the lower part is larger than a cross-sectional area of the stem.

3. The device according to claim 2, wherein the first polarized coil comprises a solenoid coil winding around the stem of the first ferrite core, and the first non-polarized coil comprises a planar coil winding on the lower part of the first ferrite core.

4. The device according to claim 2 or claim 3, wherein the other of the transmitter coupling coil and the receiver coupling coil comprises a second ferrite core, and the second ferrite core has a bar shape.

5. The device according to claim 4, wherein the second polarized coil or the second non-polarized coil of the other of the transmitter coupling coil and the receiver coupling coil is placed on top of the second ferrite core.

6. The device according to claim 4 or claim 5, wherein the one of the transmitter coupling coil and the receiver coupling coil comprises a first shield plate spaced apart from the first ferrite core, and the other of the transmitter coupling coil and the receiver coupling coil comprises a second shield plate spaced apart from the second ferrite core.

7. The device according to any one of claims 1 to 6, wherein the receiver coupling coil comprises the first polarized coil and the first nonpolarized coil, the transmitter coupling coil comprises one of the second polarized coil and the second non-polarized coil, and the load comprises a first load connected to the first polarized coil and a second load connected to the first non-polarized coil.

8. The device according to any one of claims 1 to 6, wherein one of the transmitter and the receiver which comprises the one of the transmitter coupling coil and the receiver coupling coil comprises a first switch configured to switch between the first polarized coil and the first non-polarized coil based on whether the other of the transmitter coupling coil and the receiver coupling coil comprises the second polarized coil or the second non-polarized coil.

9. The device according to claim 8 further comprising a sensor configured to determine a first current between the first polarized coil and the load and a second current between the first non-polarized coil and the load, and a controller configured to determine whether the other of the transmitter coupling coil and the receiver coupling coil comprises the second polarized coil or the second non-polarized coil based on the first current and the second current.

10. The device according to claim 8 or claim 9, wherein the receiver coupling coil comprises the first polarized coil and the first nonpolarized coil, the transmitter coupling coil comprises one of the second polarized coil and the second non-polarized coil, and the receiver comprises the first switch configured to switch between the first polarized coil and the first non-polarized coil to connect the load to one of the first polarized coil and the first non-polarized coil, based on whether the transmitter coupling coil comprises the second polarized coil or the second non-polarized coil.

11. The device according to claim 10, wherein where it is determined that the transmitter coupling coil comprises the second polarized coil, the first switch is configured to switch to connect the load to the first polarized coil, and where it is determined that the transmitter coupling coil comprises the second nonpolarized coil, the first switch is configured to switch to connect the load to the first nonpolarized coil.

12. The device according to claim 10 or claim 11, wherein the transmitter further comprises a transmitter connecting component electrically connectable to the power source and the transmitter coupling coil, the receiver further comprises a first receiver connecting component electrically connectable to the first polarized coil and the load, and a second receiver connecting component electrically connectable to the first non-polarized coil and the load, and the transmitter connecting component, the first receiver connecting component, and the second receiver connecting component are configured to create a magnetic resonance, to transfer the electrical energy from the transmitter coupling coil to the receiver coupling coil by the magnetic flux.

13. The device according to any one of claims 1 to 12, wherein the transmitter further comprises a first tuning circuit comprising a first tunable component and a first tuning switch, the receiver further comprises a second tuning circuit comprising a second tunable component and a second tuning switch, and the first tuning switch and the second tuning switch are configured to be activated based on at least one of a distance and alignment between the transmitter coupling coil and the receiver coupling coil, so that the first tunable component and the second tunable component shift the magnetic resonance.

14. The device according to any one of claims 1 to 4, wherein the other of the transmitter coupling coil and the receiver coupling coil comprises the second polarized coil comprising a solenoid coil winding.

15. A receiver mountable on a vehicle for facilitating wireless charging of the vehicle, comprising: a load electrically connectable to a battery of the vehicle; and a receiver coupling coil placed adjacent to a transmitter coupling coil of a ground assembly, configured to receive electrical energy from the transmitter coupling coil by a magnetic flux, and electrically connectable to the load to charge the battery of the vehicle, wherein the receiver coupling coil comprises a first polarized coil and a first nonpolarized coil.

16. The receiver according to claim 15, further comprising: a first switch configured to switch between the first polarized coil and the first non-polarized coil to connect the load to one of the first polarized coil and the first non-polarized coil, based on whether the transmitter coupling coil comprises a second polarized coil or a second non-polarized coil.

17. A system for facilitating wireless charging of a vehicle, comprising: a ground assembly on a ground, comprising: a power grid; and a transmitter comprising a transmitter coupling coil electrically connectable to the power grid, and configured to receive electrical energy from the power grid and transfer the electrical energy by a magnetic flux; and a vehicle assembly mounted on the vehicle, comprising: a battery of the vehicle; a receiver comprising a receiver coupling coil placed adjacent to the transmitter coupling coil, configured to receive the electrical energy from the transmitter coupling coil by the magnetic flux, and electrically connectable to a load to charge the battery of the vehicle, wherein one of the transmitter coupling coil and the receiver coupling coil comprises a first polarized coil and a first non-polarized coil, and the other of the transmitter coupling coil and the receiver coupling coil comprises one of a second polarized coil and a second non-polarized coil.

18. The system according to claim 17, wherein the one of the transmitter coupling coil and the receiver coupling coil comprises a first ferrite core, and the first polarized coil comprises a solenoid coil winding around a stem of the first ferrite core, and the first non-polarized coil comprises a planar coil winding on a lower part of the first ferrite core.

19. The system according to claim 17 or claim 18, wherein the receiver coupling coil comprises the first polarized coil and the first nonpolarized coil, the transmitter coupling coil comprises one of the second polarized coil and the second non-polarized coil, and the load comprises a first load connected to the first polarized coil and a second load connected to the first non-polarized coil.

20. The system according to claim 17 or claim 18, wherein the receiver coupling coil comprises the first polarized coil and the first nonpolarized coil, the transmitter coupling coil comprises one of the second polarized coil and the second non-polarized coil, and the receiver further comprises a first switch configured to switch between the first polarized coil and the first non-polarized coil to connect the load to one of the first polarized coil and the first non-polarized coil, based on whether the transmitter coupling coil comprises the second polarized coil or the second non-polarized coil.