Wireless charging assembly

Abstract

The invention relates to a wireless charging assembly (100) comprising an induction coil (302, 402) having a closed loop structure, and at least one capacitor (304, 404) electrically connected with the induction coil (302, 402) for enabling the induction coil (302, 402) to operate at a resonant frequency The wireless charging assembly (100) further comprises an inductive shield (308, 408) arranged between the induction coil (302, 402) and the capacitor (304, 404) for blocking the capacitor (304, 404) from effect of magnetic field. The capacitor (304, 404) is positioned within the closed loop in the wireless charging assembly.

Description

WIRELESS CHARGING ASSEMBLYFIELD OF THE INVENTION

[0001] The present invention generally relates to a wireless charging assembly, and particularly relates to a coil arrangement in a wireless charging assembly for electric vehicles.BACKGROUND OF THE INVENTION

[0002] Generally, electric vehicles are powered by batteries and such batteries require charging at periodic intervals from a power source to allow continuous usage of the equipment. Generally, the batteries are charged via wired connections; however, wireless charging technology is increasingly seen as most preferred solution due to the several advantages offered. A few such advantages include increased mobility of a user, safety, better aesthetics, and convenience.

[0003] Basic principle of wireless charging can be easily understood with the help of wireless charging in an electric vehicle (EV). Wireless charging of the EVs is accomplished by a charging assembly including a transmitting assembly and a receiving assembly. The transmitting assembly comprises a transmitter coil for generating magnetic flux for coupling with a receiver coil of the receiving assembly. Both, the transmitting assembly and the receiving assembly, include a capacitor allowing their operation at a resonant frequency. Operation at the resonant frequency enables maximum power transfer between the transmitting and receiving assemblies.

[0004] Fig. 1 illustrates a schematic representation of a conventional wireless charging assembly 100, in accordance with prior art. As illustrated in Fig. 1, wireless power is generated by a transmitting assembly 102. The transmitting assembly 102 includes a transmitter coil 104 electrically connected with a capacitor 106 (henceforth referred as a first capacitor 106) for generation of magnetic flux. The transmitter coil 104 is powered using an AC (Alternating Current) source 108.

[0005] On the other side, an equipment to be charged, such as an EV (Electric Vehicle) includes a receiving assembly 110. The receiving assembly 110 includes a receiver coil 112, electrically connected with a capacitor 114 (henceforth referred as a second capacitor 114), forreceiving the magnetic flux inductively from the transmitter coil 104. The receiving assembly 110 further includes a rectifier 116 connected between the receiver coil 112 and a battery 118 for supplying DC (Direct Current) to charge the battery 118.

[0006] The first capacitor 106 and the second capacitor 114 installed in the transmitting assembly 102 and the receiving assembly 110, respectively ensures that the inductive coupling between the transmitter coil 104 and the receiver coil 112 takes place at a resonant frequency. The inductive coupling at the resonant frequency enables maximum power transmission for wireless charging.

[0007] Fig. 2 illustrates an arrangement of the first capacitor 106 in the transmitting assembly 102 of the wireless charging assembly 100, in accordance with a prior art. In this arrangement, the transmitter coil 104 forms a closed loop structure. The first capacitor 106 are connected with and positioned adjacent to the closed loop of the transmitter coil 104. The transmitter coil 104 may be positioned over an inductive shield 120 responsible for absorbing leakage magnetic flux. The transmitter coil 104 is electrically connected with the first capacitor 106 using a high voltage cable (-10KV) 122. Given high voltage operation, the high voltage cable 122 requires additional insulation to eliminate safety risk.

[0008] The magnetic flux generated by the transmitter coil 104 interferes with operation of the first capacitor 106. To ensure normal operation of the first capacitor 106, a protective casing 124 of specialized material is provided for insulating the first capacitor 106. The protective casing 124 is made of a specialized material, and thus increases overall cost of the charging assembly 100. Further, the protective casing 124 may get heated due to the magnetic flux generated by the transmitter coil 104. Additionally, arrangement of the first capacitor 106 adjacent to the transmitter coil 104 requires additional space for accommodating the transmitting assembly 102, which may pose a challenge given a limited area of installation. Similar arrangement of capacitors and challenges are also present in the receiving assembly 110

[0009] Therefore, there remains a need of a charging assembly that can mitigate the above- mentioned shortcomings.SUMMARY OF THE INVENTION

[0010] Before the present systems, methods, and hardware enablement are described, it is to be understood that this invention in not limited to the particular systems, and methodologies described, as there can be multiple possible embodiments of the present invention which are not expressly illustrated in the present disclosure. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present invention which will be limited only by the appended claims.

[0011] This summary is provided to introduce aspects related to a wireless charging assembly, and the aspects are further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.

[0012] The present invention relates to a wireless charging assembly. The wireless charging assembly comprises an induction coil having a closed loop structure. The induction coil is electrically connected with at least one capacitor for enabling the induction coil to operate at a resonant frequency. An inductive shield is arranged between the induction coil and the capacitor for blocking the capacitor from effect of magnetic field. Further, the capacitor is positioned within the closed loop of the induction coil.

[0013] Further, the induction coil generates magnetic field for transmitting wireless power.

[0014] In one example, the induction coil couples with magnetic field for receiving wireless power.

[0015] According to one embodiment of the invention, the induction coil and the capacitor are electrically connected in series or parallel.

[0016] According to one embodiment of the invention, the inductive shield is made of a plurality of ferrite bars arranged in a closed layout.

[0017] According to one embodiment of the invention, the inductive shield has a U-shaped profile forming a slot, extending towards the induction coil, for accommodating the capacitor.

[0018] According to one embodiment of the invention, the slot and the capacitor are of same dimensions for tight packaging.

[0019] According to one embodiment of the invention, the slot includes a potting frame for holding the capacitor in a fixed position.

[0020] According to one embodiment of the invention, the wireless charging assembly is integrated in an electric vehicle for wireless charging, and the wireless charging assembly further comprises a supporting layer for holding the induction coil, the inductive shield, and the capacitor against a floor of the electric vehicle.

[0021] Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The foregoing summary, as well as the following detailed description of preferred embodiments, are better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings exemplary constructions of the invention; however, the invention is not limited to the specific methods and system disclosed. The foregoing aspects and many of the advantages of this invention will become more readily appreciated as the same becomes better understood by the reference to the following detailed description, when taken in conjunction with the accompanying drawings. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. In the drawings:

[0023] Fig. 1 illustrates a schematic representation of a conventional wireless charging assembly, in accordance with a prior art;

[0024] Fig. 2 illustrates an arrangement of capacitors in a transmitting assembly of a conventional wireless charging assembly, in accordance with a prior art;

[0025] Fig. 3A illustrates a schematic view of a transmitting assembly of a wireless charging assembly, in accordance with an embodiment of present invention;

[0026] Fig. 3B illustrates a vertical cross-sectional view of a section of the transmitting assembly of the wireless charging assembly shown in Fig. 3A;

[0027] Fig. 4A illustrates a perspective view of a receiving assembly of the wireless charging assembly, in accordance with an embodiment of present invention; and

[0028] Fig. 4B illustrates an exploded view of the receiving assembly of the wireless charging assembly shown in Fig. 4A.DETAILED DESCRIPTION OF THE INVENTION

[0029] The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. Each embodiment described in this disclosure is provided merely as an example or illustration of the present invention, and should not necessarily be construed as preferred or advantageous over other embodiments. The detailed description includes specific details for the purpose of providing a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.

[0030] The words “comprising,” “having,” “containing,” and “including,” and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items.

[0031] It must also be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. Although any systems and methods similar or equivalent to those described herein can be usedin the practice or testing of embodiments of the present invention, the preferred, systems and methods are now described.

[0032] The present invention relates to a wireless charging assembly including a transmitting assembly and a receiving assembly for transmission and reception of magnetic flux, for wireless charging. The transmitting assembly further comprises a transmitter coil generating magnetic flux upon supply of AC (Alternating Current). The magnetic flux inductively couples with a receiver coil of the receiving assembly. The magnetic flux results in generation of AC in the receiver coil. The AC is rectified into DC (Direct Current) for charging the batteries, in the EV (Electric Vehicle). As explained earlier, each of the transmitter coil and the receiver coil is electrically connected with a capacitor by a high voltage cable. The capacitor in conjunction with the respective transmitter coil and the receiver coil ensures that electromagnetic coupling takes place at a resonant frequency. Electromagnetic coupling at a resonant frequency enables maximum energy transfer between the transmitter coil and the receiver coil.

[0033] Both, the transmitter coil and the receiver coil are formed by arranging a continuous strand of wire, such as a copper wire, in a closed manner, to form a closed loop. The closed loop may be of different shapes, such as square or rectangular shape. The capacitor is positioned within the closed loop of each of the transmitter coil and the receiver coil. Positioning capacitor within the closed loop provides several operational advantages. Primarily, the transmitting assembly and the receiving assembly require lesser area for installation without any loss in performance. Secondly, coupling of the magnetic flux generated by the transmitter coil with the receiver coil increases. Thirdly, the capacitors are insulated from the magnetic flux without requiring any casing of specialized material. Further, operational safety of High Voltage (HV) electrical connections between the capacitors, and the transmitter coil and the receiver coil, improves substantially. Further details of the arrangement of the capacitors in the charging assembly have been described with the help of following embodiments.

[0034] Fig. 3A illustrates a schematic view of a transmitting assembly 300 of a wireless charging assembly, in accordance with an embodiment of present invention. The transmitting assembly 300 includes a transmitter coil 302 generating magnetic flux. The transmitter coil 302 is formed by arranging a continuous strand of wire, such as a copper wire, in a closed manner,to form a closed loop. The closed loop may be of different shapes, such as square or rectangular shape. The magnetic flux generated by the transmitter coil 302 electromagnetically couples with a receiver coil 402 of a receiving assembly 400 (shown in Fig. 4A) for energy transfer. To accomplish efficient energy transfer at a resonant frequency, the transmitter coil 302 is electrically connected with a capacitor 304. The capacitor 304 is electrically connected to the transmitter coil 302 in series or parallel by a High Voltage (HV) cable 306. The capacitor 304 electrically connected with the High Voltage (HV) cable 306 is positioned within i.e. center of the closed loop of the transmitter coil 302. Positioning the capacitor 304 and the HV cable 306 within the closed loop of the transmitter coil 302 reduces overall area of the charging assembly 300 and reduces risk of short circuit due to the HV cable 306. Further, the HV cable 306 requires less insulation, thereby reducing overall cost of the charging assembly 300.

[0035] The capacitor 304 positioned within the closed loop of the transmitter coil 302 is shielded by an inductive shield 308 from magnetic flux generated by the transmitter coil 302. The inductive shield 308 is placed in a horizontal plane parallel to the transmitter coil 302 such that the inductive shield 308 forms a barrier between the capacitor 304 and the transmitter coil 302. The inductive shield 308 may act as a supporting structure for positioning the capacitor 304 within the closed loop of the transmitter coil 302. In order to effectively insulate the capacitor 304 from magnetic flux, the inductive shield 308 may be made of a magnetic material with high magnetic permeability and high saturation magnetic flux, such as ferrite. Ferrites are ceramic compounds derived from iron oxides. In this example, the inductive shield 308 may be formed through an arrangement of a plurality of ferrite bars in a closed layout, such as in a rectangular layout. In one example, the inductive shield 308 may have a surface area greater than that of the transmitter coil 302.

[0036] Fg. 3B illustrates a vertical cross-sectional view of a section of the transmitting assembly 300 of the wireless charging assembly shown in Fig. 3A. As illustrated, the inductive shield 308 comprises a slot 310 forming a holding region for positioning the capacitor 304. The slot 310 extends towards the transmitter coil 302 of the transmitting assembly 300. It is already described above with reference to Fig. 3A that the capacitor 304 is positioned within the closed loop of the transmitter coil 302. Therefore, it must be understood that the capacitor 304 is positioned over the slot 310 and within the center of the closed loop of the transmitter coil 302, where the inductive shield 308 comprising the slot 310 is present beneath the transmitter coil 302.

[0037] The inductive shield 308 may have an inverted ‘U’ shaped profile, as illustrated in the vertical cross-sectional view shown in Fig. 3B The inductive shield 308 comprises a base region 312 and phalanges 314. The base region 312 forming the slot 310 holds the capacitor 304. The phalanges 314 defining a peripheral region act as a supporting surface for positioning the transmitting coil 302.

[0038] In an implementation, the transmitting assembly 300 may be installed in ground for use as a wireless charging point / station. In such implementation, the transmitter coil 302 is positioned nearer to the surface of ground. The transmitter coil 302 may be covered by a charging pad at the top to protect the transmitting assembly 300 from physical damage and environmental agents like dust and water. The transmitter coil 302 may be one of Circular Rectangular Pad (CRP), Circular Pad (CP), Homogenous Pad (HP), Double-D Pad (DDP), Double-D Quadrature Pad (DDQP), and Bipolar Pad (BP). The transmitter coil 302 may be positioned over the upper surface of the inductive shield 308 such that magnetic flux does not interfere with working of the capacitor. The magnetic flux generated by the transmitter coil 302 is directed upwards for coupling with the receiver coil 402 of the receiving assembly 400 (shown in Fig. 4A).

[0039] Fig. 4A illustrates a perspective view of the receiving assembly 400 of the wireless charging assembly, in accordance with an embodiment of present invention, and Fig. 4B illustrates an exploded view of the receiving assembly 400 of the wireless charging assembly shown in Fig. 4A. The receiving assembly 400 includes the receiver coil 402 for receiving magnetic flux. The receiver coil 402 is formed by arranging a continuous strand of wire, such as a copper wire, in a closed manner, to form a closed loop. The closed loop may be of different shapes, such as square or rectangular shape. The receiver coil 402 of the receiving assembly 400 electromagnetically couples with the magnetic flux generated by the transmitter coil 302 of the transmitting assembly 300 for energy transfer. To accomplish efficient energy transfer at a resonant frequency, the receiver coil 402 is electrically connected with a capacitor 404. The capacitor 404 is electrically connected to the receiver coil 402 in series or parallel using a High Voltage (HV) cable. The capacitor 404 electrically connected with the High Voltage (HV) cable is positioned within i.e., center of the closed loop of the receiver coil 402. Positioning the capacitor 404 and the HV cable within closed loop of the receiver coil 402 reduces risk of short circuit due to the HV cable and reduces overall area of the receiving assembly 400. Further,the HV cable requires less insulation, resulting into reduced overall cost of the receiving assembly 400.

[0040] The capacitor 404 positioned within closed loop of the receiver coil 402 is shielded by an inductive shield 408 from magnetic flux coupling with the receiver coil 402. The inductive shield 408 is placed in a horizontal plane parallel to the receiver coil 302 such that the inductive shield 408 forms a barrier between the capacitor 404 and the receiver coil 402. The inductive shield 408 also acts as a supporting structure for positioning the capacitor 404 within loop of the receiver coil 402. In order to effectively insulate the capacitor 404 from magnetic flux, the inductive shield 408 may be made up of a magnetic material with high magnetic permeability and high saturation magnetic flux, such as ferrite. A plurality of ferrite bars is arranged in a closed loop to form the inductive shield 408. In this example, the inductive shield 408 may be formed through an arrangement of a plurality of ferrite bars in a closed layout, such as in a rectangular layout. In one example, the inductive shield 408 may have a surface area greater than that of the receiver coil 402.

[0041] As illustrated in Fig. 4B, the inductive shield 408 comprises a slot 410 forming a holding region for positioning the capacitor 404. The slot 410 extends towards the receiver coil 402 of the receiving assembly 400. It is already described above with reference to Fig. 4A that the capacitor 404 is positioned within the closed loop of the receiver coil 402. Therefore, it must be understood that the capacitor 404 is positioned over the slot 410 and within the center of the closed loop of the receiver coil 402, where the inductive shield 408 comprising the slot 410 is present above the receiver coil 402.

[0042] In one implementation, the slot 410 may include a potting frame for holding the capacitor 404 in a fixed position. The potting frame may include adaptations for receiving the capacitor 404. The potting frame provides additional support to the capacitor 404 so that the capacitor 404 fits tightly over the slot 410 of the inductive shield 408.

[0043] In an implementation, the receiving assembly 400 may be installed in an Electric Vehicle (EV). In such implementation, the receiver coil 402 is positioned to face ground surface for enabling maximum coupling during wireless charging. The receiver coil 402 in the receiving assembly 400 is one of Circular Rectangular Pad (CRP), Circular Pad (CP), Homogenous Pad (HP), Double-D Pad (DDP), Double-D Quadrature Pad (DDQP), and BipolarPad (BP). The receiver coil 402 with the closed loop is positioned against the lower surface of the inductive shield 408 having a slot 410. The slot 410 matches profile of the capacitor 404 such that the capacitor 404 is secured tightly in the slot 410. The receiver coil 402 may be held against a lower surface of the inductive shield 408 by a supporting plate 420. The supporting plate 420 may include a plurality of grooves to accommodate the receiver coil 402. The supporting plate 420 may further include an indentation 422 to accommodate the slot 410 of the inductive shield 408. The supporting plate 420 provides a resting surface to the inductive shield 408 having the capacitor 404. The supporting plate 420 may be integrated with a bottom surface i.e. chassis of the EV. The supporting plate 420 may be made of a non-magnetic material to provide protection from physical damage and environmental agents.

[0044] Positioning the capacitor 304, 404 within the closed loop in each of the transmitter coil 302 and the receiver coil 402 of the wireless charging assembly provides substantial technical advancements over the state of art. In accordance with aforesaid disclosure, installation of the transmitting assembly 300 and the receiving assembly 400 require less area for installation. In the EVs, the receiving assembly 400 provides additional space for accommodating different parts or making the EV body more compact. The HV cable confined within the transmitting assembly 300 and the receiving assembly 400 minimizes risk of short circuits. The capacitors 304, 404 are insulated from the magnetic flux allowing their uninterrupted operation. Further, there is no requirement of providing specialized casing to insulate the capacitors 304, 404, thereby reducing overall cost of installation of the charging assembly.

[0045] The present wireless charging assembly may be designed to wirelessly charge the EV in static position or in dynamic motion. The transmitting assembly may include other components such as rectifier, DC-DC converter, High Frequency (HF) inverter, current injector, vehicle position sensors along with the transmitter coil and capacitor for generating magnetic flux, as per requirement. Similarly, the receiving assembly installed in the EV may include a rectifier, DC-DC converter for coupling with magnetic flux and supplying current to charge batteries.

[0046] The embodiments in the invention have been described with reference to the wireless charging assembly for the electric vehicle. However, reference to the electric vehicle is for illustration and does not limit scope of the invention. The technical features provided in theinvention may be employed in the wireless charging assembly for other electronic equipment and mobility solutions.

[0047] In the above detailed description, reference is made to the accompanying drawings that form a part thereof, and illustrate the best mode presently contemplated for carrying out the invention. However, such description should not be considered as any limitation of scope of the present invention. The structure thus conceived in the present description is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence.

[0048] Any combination of the above features and functionalities may be used in accordance with one or more embodiments. In the foregoing specification, embodiments have been described with reference to numerous specific details that may vary from implementation to implementation. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. The sole and exclusive indicator of the scope of the invention, and what is intended by the applicants to be the scope of the invention, is the literal and equivalent scope of the set as claimed in claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction.

Claims

We claim:

1. A wireless charging assembly (100), comprising: an induction coil (302, 402) having a closed loop structure; at least one capacitor (304, 404) electrically connected with the induction coil (302, 402) for enabling the induction coil (302, 402) to operate at a resonant frequency; and an inductive shield (308, 408) arranged between the induction coil (302, 402) and the capacitor (304, 404) for blocking the capacitor (304, 404) from effect of magnetic field, wherein the capacitor (304, 404) is positioned within the closed loop.

2. The wireless charging assembly (100) as claimed in claim 1, wherein the induction coil (302) generates magnetic field for transmitting wireless power.

3. The wireless charging assembly (100) as claimed in claim 1, wherein the induction coil (402) couples with magnetic field for receiving wireless power.

4. The wireless charging assembly (100) as claimed in claim 1, wherein the induction coil (302, 402) and the capacitor (304, 404) are electrically connected in series or parallel.

5. The wireless charging assembly (100) as claimed in claim 1, wherein the inductive shield (308, 408) is made of a plurality of ferrite bars arranged in a closed layout.

6. The wireless charging assembly (100) as claimed in claim 1, wherein the inductive shield (308, 408) has a U-shaped profile forming a slot (310, 410), extending towards the induction coil (302, 402), for accommodating the capacitor (304, 404).

7. The wireless charging assembly (100) as claimed in claim 6, wherein the slot (310, 410) and the capacitor (304, 404) are of same dimensions for tight packaging.

8. The wireless charging assembly (100) as claimed in claim 6, wherein the slot (310, 410) includes a potting frame for holding the capacitor (304, 404) in a fixed position.

9. The wireless charging assembly (100) as claimed in claim 3, wherein the wireless charging assembly (100) is integrated in an electric vehicle for wireless charging.

10. The wireless charging assembly (100) as claimed in claim 9, further comprises a supporting layer (420) for holding the induction coil (402), the inductive shield (408), and a capacitor (404) against a floor of the electric vehicle.

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