Claims:1. A receiver unit (108) of a wireless power transfer system (100), the receiver unit (108) comprising:
a main receiver coil (120);
a plurality of auxiliary receiver coils (122, 122a, 122b) disposed about a central axis (502) of the main receiver coil (120);
an integrated electronic component (117) comprising:
a substrate (132);
a receiver drive subunit (118) formed on the substrate (132), wherein the receiver drive subunit (118) comprises:
a main converter (124) operatively coupled to the main receiver coil (120), wherein the main converter (124) comprises a main output terminal (210); and
a plurality of auxiliary converters (126, 126a, 126b) operatively coupled to the plurality of auxiliary receiver coils (122, 122a, 122b), wherein the plurality of auxiliary converters (126, 126a, 126b) is operatively coupled to each other to form an auxiliary output terminal (212) coupled in series to the main output terminal (210) to form a common output terminal (214);
a communication subunit (130) formed on the substrate (132) and operatively coupled to the receiver drive subunit (118); and
a controller (128) disposed on the substrate (132) and operatively coupled to at least one of the common output terminal (214), an alternating current terminal (216) of the main converter (124), alternating current terminals (218, 220) of the plurality of auxiliary converters (126, 126a, 126b), and the communication subunit (130), wherein the controller (128) is configured to:
determine one or more circuit parameters corresponding to at least one of the common output terminal (214), the alternating current terminal (216) of the main converter (124), and the alternating current terminals (218, 220) of the plurality of auxiliary converters (126, 126a, 126b); and
control at least the communication subunit (130) based on the one or more circuit parameters.
2. The receiver unit (108) as claimed in claim 1, wherein one auxiliary converter of the plurality of auxiliary converters (126, 126a, 126b) is operatively coupled in parallel to another auxiliary converter of the plurality of auxiliary converters (126, 126a, 126b).
3. The receiver unit (108) as claimed in claim 1, wherein one auxiliary converter of the plurality of auxiliary converters (126, 126a, 126b) is operatively coupled in series to another auxiliary converter of the plurality of auxiliary converters (126, 126a, 126b).
4. The receiver unit (108) as claimed in claim 1, wherein at least one of the plurality of auxiliary converters (126, 126a, 126b) is at least one of a passive rectifier, a hybrid rectifier, and an active rectifier.
5. The receiver unit (108) as claimed in claim 1, wherein the communication subunit (130) is coupled to at least one of the alternating current terminal (216) of the main converter (124), the alternating current terminals (218, 220) of the plurality of auxiliary converters (126, 126a, 126b), and the common output terminal (214).
6. The receiver unit (108) as claimed in claim 1, wherein the substrate (132) comprises a silicon wafer.
7. The receiver unit (108) as claimed in claim 1, wherein the receiver drive subunit (118) comprises a plurality of first switches (206, 208) comprising at least one of a diode, an insulated gate bipolar transistor, a metal oxide semiconductor field effect transistor, a field-effect transistor, an injection enhanced gate transistor, an integrated gate commutated thyristor, a gallium nitride based switch, a silicon carbide based switch, and a gallium arsenide based switch.
8. The receiver unit (108) as claimed in claim 7, wherein the communication subunit (130) comprises at least one of at least one second switch (222) and a demodulator (136).
9. The receiver unit (108) as claimed in claim 8, further comprising a third switch (204) formed on the substrate (132) and coupled across the auxiliary output terminal (212).
10. The receiver unit (108) as claimed in claim 1, wherein the integrated electronic component (117) is an application specific integrated circuit (ASIC), a very large-scale integration (VLSI) chip, a microelectromechanical system (MEMS), or a system on chip (SoC).
11. A wireless power transfer system (100) comprising:
a transmitter unit (106);
a receiver unit (108) operatively coupled to the transmitter unit (106), wherein the receiver unit (108) comprises:
a main receiver coil (120);
a plurality of auxiliary receiver coils (122, 122a, 122b) disposed about a central axis (502) of the main receiver coil (120);
an integrated electronic component (117) comprising:
a substrate (132);
a receiver drive subunit (118) formed on the substrate (132), wherein the receiver drive subunit (118) comprises:
a main converter (124) operatively coupled to the main receiver coil (120), wherein the main converter (124) comprises a main output terminal (210); and
a plurality of auxiliary converters (126, 126a, 126b) operatively coupled to the plurality of auxiliary receiver coils (122, 122a, 122b), wherein the plurality of auxiliary converters (126, 126a, 126b) is operatively coupled to each other to form an auxiliary output terminal (212) coupled in series to the main output terminal (210) to form a common output terminal (214);
a communication subunit (130) disposed on the substrate (132) and operatively coupled to the receiver drive subunit (118); and
a controller (128) disposed on the substrate (132) and operatively coupled to at least one of the common output terminal (214) ), an alternating current terminal (216) of the main converter (124), alternating current terminals (218, 220) of the plurality of auxiliary converters (126, 126a, 126b), and the communication subunit (130), wherein the controller (128) is configured to:
determine one or more circuit parameters corresponding to at least one of the common output terminal (214), the alternating current terminal (216) of the main converter (124), and the alternating current terminals (218, 220) of the plurality of auxiliary converters (126, 126a, 126b); and
control at least the communication subunit (130) based on the one or more circuit parameters.
12. The wireless power transfer system (100) as claimed in claim 11, wherein the communication subunit (130) comprises at least one of a plurality of switches (222) and a demodulator (136).
13. The wireless power transfer system (100) as claimed in claim 12, further comprising a plurality of impedance components (230), wherein a switch of the plurality of switches (222) is coupled to a corresponding impedance component of the plurality of impedance components (230).
14. The wireless power transfer system (100) as claimed in claim 13, wherein the switch of the plurality of switches (222) is operatively coupled to at least one branch (216a, 216b, 218a, 218b, 220a, 220b) of the alternating current terminal (216) of at least one of the main converter (124) and the alternating current terminals (218, 220) of the plurality of auxiliary converters (126, 126a, 126b) via the corresponding impedance component.
15. The wireless power transfer system (100) as claimed in claim 13, wherein the switch of the plurality of switches (222) is coupled to the common output terminal (214) via the corresponding impedance component.
16. The wireless power transfer system (100) as claimed in claim 12, wherein one switch of the plurality of switches (222) is coupled to another switch of the plurality of switches (222).
17. A method of operation of a wireless power transfer system (100), the method comprising:
determining, by a controller, one or more circuit parameters corresponding to at least one of a common output terminal, an alternating current terminal of a main converter, and alternating current terminals of a plurality of auxiliary converters, wherein the common output terminal is formed by connecting an auxiliary output terminal to a main output terminal of the main converter in series, wherein the auxiliary output terminal is formed by operatively coupling the plurality of auxiliary converters of a receiver drive subunit to each other;
controlling operation of a communication subunit based on the one or more circuit parameters, wherein the communication subunit is operatively coupled to the receiver drive subunit;
inducing a first voltage, by a transmitter coil of a transmitter unit, at at least one of a main receiver coil and a plurality of auxiliary receiver coils based on an alignment of the main receiver coil and the plurality of auxiliary receiver coils with the transmitter coil, wherein the plurality of auxiliary converters is operatively coupled to the plurality of auxiliary receiver coils and the main converter is operatively coupled to the main receiver coil; and
generating a second voltage at the common output terminal.
18. The method as claimed in claim 17, wherein controlling operation of the communication subunit comprises providing a gate control signal, by the controller, to a plurality of switches of the communication subunit based on the one or more circuit parameters.
19. The method as claimed in claim 17, further comprising demodulating information received from the transmitter unit by a demodulator of the communication subunit.
20. An integrated electronic component (117) for a receiver unit (108) of a wireless power transfer system (100), the integrated electronic component (117) comprising:
a substrate (132);
a receiver drive subunit (118) formed on the substrate (132), wherein the receiver drive subunit (118) comprises:
a main converter (124) configured to be operatively coupled to a main receiver coil (120), wherein the main converter (124) comprises a main output terminal (210); and
a plurality of auxiliary converters (126, 126a, 126b) configured to be operatively coupled to a plurality of auxiliary receiver coils (122, 122a, 122b), wherein the plurality of auxiliary converters (126, 126a, 126b) is operatively coupled to each other to form an auxiliary output terminal (212) coupled in series to the main output terminal (210) to form a common output terminal (214);
a communication subunit (130) formed on the substrate (132) and operatively coupled to the receiver drive subunit (118); and
a controller (128) disposed on the substrate (132) and operatively coupled to at least one of the receiver drive subunit (118), and the communication subunit (130), wherein the controller (128) is configured to:
determine one or more circuit parameters corresponding to the receiver drive subunit (118); and
control at least the communication subunit (130) based on the one or more circuit parameters.
, Description:CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Patent of Addition of Indian Patent Application, Application Number, 201841014948, entitled “A RECEIVER UNIT OF A WIRELESS POWER TRANSFER SYSTEM AND AN ASSOCIATED METHOD THEREOF” filed on April 19, 2018, the contents of which are hereby incorporated by reference. Further, this application is an improvement in or modification of the original invention. The Indian Patent Application discloses various embodiments of a wireless power transfer system. In particular, various embodiments disclose different arrangements of the auxiliary receiver coils with respect to the main receiver coil. Furthermore, the embodiments disclose the arrangement of the receiver coils with respect to associated converters.
BACKGROUND
[0002] Embodiments of the present invention relate generally to a power transfer system and more particularly to a wireless power transfer system. In particular, the present invention relates to a receiver unit of the wireless power transfer systems.
[0003] A wireless power transfer system includes a transmitter coil, a receiver coil, and corresponding electronic circuitry. Typically, efficiency of power transfer between the transmitter coil and the receiver coil is compromised due to misalignment between the transmitter coil and the receiver coil. Different techniques have been proposed for overcoming the shortcomings in power transfer due to misalignment between the transmitter coil and the receiver coil. These techniques entail use of an electronic circuitry along with the different arrangement of the receiver coils. However, the packaging of the electronic circuitry remains a challenge.
[0004] Thus, there is a need for an enhanced receiver unit of the wireless power transfer system and an associated method.

BRIEF DESCRIPTION
[0005] In accordance with one embodiment of the present invention, a receiver unit of a wireless power transfer system is presented. The receiver unit includes a main receiver coil, a plurality of auxiliary receiver coils disposed about a central axis of the main receiver coil, and an integrated electronic component. The integrated electronic component includes a substrate, a receiver drive subunit formed on the substrate, where the receiver drive subunit includes a main converter operatively coupled to the main receiver coil, where the main converter includes a main output terminal and a plurality of auxiliary converters operatively coupled to the plurality of auxiliary receiver coils, where the plurality of auxiliary converters is operatively coupled to each other to form an auxiliary output terminal coupled in series to the main output terminal to form a common output terminal. Further, the integrated electronic component includes a communication subunit formed on the substrate and operatively coupled to the receiver drive subunit and a controller disposed on the substrate and operatively coupled to at least one of the common output terminal, an alternating current terminal of the main converter, alternating current terminals of the plurality of auxiliary converters, and the communication subunit, where the controller is configured to determine one or more circuit parameters corresponding to at least one of the common output terminal, the alternating current terminal of the main converter, and the alternating current terminals of the plurality of auxiliary converters and control at least the communication subunit based on the one or more circuit parameters.
[0006] In accordance with another embodiment of the present invention, a wireless power transfer system is presented. The wireless power transfer system includes a transmitter unit, a receiver unit operatively coupled to the transmitter unit, where the receiver unit includes a main receiver coil, a plurality of auxiliary receiver coils disposed about a central axis of the main receiver coil, and an integrated electronic component. The integrated electronic component includes a substrate and a receiver drive subunit formed on the substrate. The receiver drive subunit includes a main converter operatively coupled to the main receiver coil, where the main converter includes a main output terminal; and a plurality of auxiliary converters operatively coupled to the plurality of auxiliary receiver coils, where the plurality of auxiliary converters is operatively coupled to each other to form an auxiliary output terminal coupled in series to the main output terminal to form a common output terminal. The integrated electronic component further includes a communication subunit disposed on the substrate and operatively coupled to the receiver drive subunit and a controller disposed on the substrate and operatively coupled to at least one of the common output terminal, an alternating current terminal of the main converter, alternating current terminals of the plurality of auxiliary converters, and the communication subunit, where the controller is configured to determine one or more circuit parameters corresponding to at least one of the common output terminal, the alternating current terminal of the main converter, and the alternating current terminals of the plurality of auxiliary converters and control at least the communication subunit based on the one or more circuit parameters.
[0007] In accordance with yet another embodiment of the present invention, a method of operation of a wireless power transfer system is presented. The method includes determining, by a controller, one or more circuit parameters corresponding to at least one of a common output terminal, an alternating current terminal of a main converter, and alternating current terminals of a plurality of auxiliary converters, where the common output terminal is formed by connecting an auxiliary output terminal to a main output terminal of the main converter in series, where the auxiliary output terminal is formed by operatively coupling the plurality of auxiliary converters of a receiver drive subunit to each other. Further, the method includes controlling operation of a communication subunit based on the one or more circuit parameters, where the communication subunit is operatively coupled to the receiver drive subunit. Furthermore, the method includes inducing a first voltage, by a transmitter coil of a transmitter unit, at at least one of a main receiver coil and a plurality of auxiliary receiver coils based on an alignment of the main receiver coil and the plurality of auxiliary receiver coils with the transmitter coil, where the plurality of auxiliary converters is operatively coupled to the plurality of auxiliary receiver coils and the main converter is operatively coupled to the main receiver coil. Additionally, the method includes generating a second voltage at the common output terminal.
[0008] In accordance with yet another embodiment of the present invention, an integrated electronic component for a receiver unit of a wireless power transfer system is presented. The integrated electronic component includes a substrate, a receiver drive subunit formed on the substrate, where the receiver drive subunit includes a main converter configured to be operatively coupled to a main receiver coil, where the main converter includes a main output terminal; and a plurality of auxiliary converters configured to be operatively coupled to a plurality of auxiliary receiver coils, where the plurality of auxiliary converters is operatively coupled to each other to form an auxiliary output terminal coupled in series to the main output terminal to form a common output terminal. Further, the integrated electronic component includes a communication subunit formed on the substrate and operatively coupled to the receiver drive subunit. Furthermore, the integrated electronic component includes a controller disposed on the substrate and operatively coupled to at least one of the receiver drive subunit and the communication subunit, where the controller is configured to determine one or more circuit parameters corresponding to the receiver drive subunit and control at least the communication subunit based on the one or more circuit parameters.
DRAWINGS
[0009] These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
[0010] FIG. 1 is a block diagram of a wireless power transfer system in accordance with an embodiment of the present specification;
[0011] FIG. 2 is a schematic representation of a receiver unit of the wireless power transfer system of FIG. 1 in accordance with an embodiment of the present specification;
[0012] FIG. 3 is a schematic representation of a receiver unit of the wireless power transfer system of FIG. 1 in accordance with an embodiment of the present specification;
[0013] FIG. 4 is a schematic representation of a receiver unit of the wireless power transfer system of FIG. 1 in accordance with an embodiment of the present specification; and
[0014] FIG. 5 is a schematic representation of receiver coils of the wireless power transfer system of FIG. 1 in accordance with an embodiment of the present specification.
DETAILED DESCRIPTION
[0015] Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this specification belongs. The terms "first", "second", and the like, as used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Also, the terms "a" and "an" do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. The use of "including," "comprising" or "having" and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms "connected" and "coupled" are not restricted to physical or mechanical connections or couplings, and can include electrical connections or couplings, whether direct or indirect. Furthermore, terms "circuit" and "circuitry" and "controlling unit" may include either a single component or a plurality of components, which are active and/or passive and are connected or otherwise coupled together to provide the described function. In addition, the term operatively coupled as used herein includes wired coupling, wireless coupling, electrical coupling, magnetic coupling, radio communication, software based communication, or combinations thereof.
[0016] As will be described in detail hereinafter, various embodiments of a wireless power transfer (WPT) system are disclosed. In particular, the system and method disclose employing an exemplary receiver unit having a plurality of auxiliary receiver coils disposed about a central axis of a main receiver coil. Further, the embodiments disclose the arrangement of the receiver coils with respect to associated converters. Additionally, different embodiments of the integrated electronic component of the receiver unit is disclosed. The exemplary receiver unit may be employed in wireless charging systems, such as but not limited to a mobile phone, a laptop, an electric vehicle, consumer electronic products, and the like.
[0017] FIG. 1 is a block diagram of a wireless power transfer system 100 in accordance with an embodiment of the present specification. The wireless power transfer system 100 includes a wireless power transfer unit 102 and a power source 104. In the illustrated embodiment, the wireless power transfer unit 102 includes a transmitter unit 106, a receiver unit 108, and a field focusing coil 110. The transmitter unit 106 is magnetically coupled to the receiver unit 108 via the field focusing coil 110. The field focusing coil 110 is used to focus a magnetic field from the transmitter unit 106 to the receiver unit 108. In another embodiment, the field focusing coil 110 may not be present in the wireless power transfer unit 102.
[0018] The transmitter unit 106 includes a transmitter (Tx) drive subunit 112 coupled to a transmitter (Tx) coil 114. In one embodiment, the transmitter drive subunit 112 may be a converter. The transmitter drive subunit 112 includes semiconductor switches such as an insulated gate bipolar transistor, a metal oxide semiconductor field effect transistor, a field-effect transistor, an injection enhanced gate transistor, an integrated gate commutated thyristor, a gallium nitride based switch, a silicon carbide based switch, a gallium arsenide based switch, diodes, or the like. In one embodiment, the transmitter coil 114 may be a wound copper wire.
[0019] The receiver unit 108 includes a receiver (Rx) coil 116 and an integrated electronic component 117. In accordance with aspects of the present specification, the receiver coil 116 includes a main receiver coil 120 and a plurality of auxiliary receiver coils 122. The plurality of auxiliary receiver coils 122 is disposed about a central axis of the main receiver coil 120. In one embodiment, each of the main receiver coil 120 and the plurality of auxiliary receiver coils 122 includes a wound copper wire.
[0020] In one embodiment, the main receiver coil 120 and the plurality of auxiliary receiver coils 122 are resonant coils. In particular, each of the main receiver coil 120 and the plurality of auxiliary receiver coils 122 may be coupled to a corresponding capacitor (not shown). In one specific embodiment, the main receiver coil 120 and the plurality of auxiliary receiver coils 122 are compatible with a Wireless Power Consortium (WPC) standard (Qi) that is defined in a frequency range of 100 kHz to 200 kHz.
[0021] The integrated electronic component 117 is an integrated circuit (IC). In one embodiment, the integrated electronic component 117 may be an application specific integrated circuit (ASIC), a very large-scale integration (VLSI) chip, a microelectromechanical system (MEMS), or system on chip (SoC). The integrated electronic component 117 also includes a receiver drive subunit 118, a controller 128, a communication subunit 130, and a substrate 132. The controller 128, the communication subunit 130, and the receiver drive subunit 118 are disposed/formed on the substrate 132. In one embodiment, the substrate 132 may include a silicon wafer.
[0022] Further, the receiver drive subunit 118 includes a main converter 124 and a plurality of auxiliary converters 126. Each of the main converter 124 and the plurality of auxiliary converters 126 include a plurality of first switches (not shown in FIG. 1). The plurality of first switches includes semiconductor switches, such as an insulated gate bipolar transistor, a metal oxide semiconductor field effect transistor, a field-effect transistor, an injection enhanced gate transistor, an integrated gate commutated thyristor, a gallium nitride based switch, a silicon carbide based switch, a gallium arsenide based switch, diodes, or the like.
[0023] The main receiver coil 120 is coupled to the main converter 124. The main converter 124 includes a main output terminal (not shown in FIG. 1) and is configured to rectify a voltage induced at the main receiver coil 120. Further, the auxiliary receiver coils 122 are coupled to the auxiliary converters 126. The auxiliary converters 126 are configured to rectify voltages induced at the auxiliary receiver coils 122. In one embodiment, each auxiliary receiver coil 122 is coupled to a corresponding auxiliary converter 126. In one embodiment, at least one of the main converter 124 and the plurality of auxiliary converters 126 is a passive rectifier. In one specific embodiment, the passive rectifier is a diode rectifier. In another embodiment, at least one of the main converter 124 and the plurality of auxiliary converters 126 includes a hybrid rectifier and an active rectifier.
[0024] Furthermore, the plurality of auxiliary converters 126 is coupled to each other to form an auxiliary output terminal (not shown in FIG. 1). In accordance with aspects of the present specification, the main output terminal of the main converter 124 is coupled to the auxiliary output terminal in series to form a common output terminal (not shown in FIG. 1). Further, a load (not shown in FIG. 1) is coupled across the common output terminal. As noted hereinabove, the exemplary receiver unit 108 includes the auxiliary receiver coils 122 in addition to the main receiver coil 120. The combination of the main receiver coil 120 and the auxiliary receiver coils 122 is configured to provide a desired voltage to the load, via the main and auxiliary converters 124, 126, even in an event of misalignment of the main receiver coil 120 with respect to the transmitter coil 114.
[0025] It may be noted herein that if a central axis of the transmitter coil 114 is aligned with a central axis of the main receiver coil 120, the main receiver coil 120 is aligned with the transmitter coil 114. The central axis of the transmitter coil 114 is an axis passing through a center of the transmitter coil 114. Similarly, the central axis of the main receiver coil 120 is an axis passing through a center of the main receiver coil 120.
[0026] The controller 128 includes a microcontroller, a microprocessor, a processing unit, microcomputer, digital signal processors (DSPs), field programmable gate arrays (FPGAs), and/or any other programmable circuits or the like. Further, the controller 128 is operatively coupled to the receiver drive subunit 118 and the communication subunit 130. In particular, the controller 128 is operatively coupled to the common output terminal and alternating current (AC) terminal of the receiver drive subunit 118. The alternating current terminal of the receiver drive subunit 118 includes alternating current terminal of the main converter 124 and alternating current terminals of the auxiliary converters 126. The communication subunit 130 includes at least one second switch. The at least one second switch includes semiconductor switches, such as an insulated gate bipolar transistor, a metal oxide semiconductor field effect transistor, a field-effect transistor, an injection enhanced gate transistor, an integrated gate commutated thyristor, a gallium nitride based switch, a silicon carbide based switch, a gallium arsenide based switch, diodes, or the like.
[0027] The controller 128 is configured to determine one or more circuit parameters of the receiver drive subunit 118. In particular, the controller 128 is configured to determine the one or more circuit parameters of at least one of the common output terminal, an alternating current terminal of the main converter 124, and alternating current terminals of the plurality of auxiliary converters 126. The term ‘circuit parameters,’ as used herein, may refer to voltage, current, frequency, and power. Further, the controller 128 is configured to control operation of the communication subunit 130 based on the determined circuit parameters. In particular, the controlling operation of the communication subunit 130 includes activating/deactivating the at least one second switch.
[0028] It should be noted herein that the controlling operation of the communication subunit 130 causes a variation in an impedance of the receiver unit 108. In particular, the impedance loading the main receiver coil 120 and the impedance loading the auxiliary receiver coils 122, as seen from the transmitter unit 106 end is varied. As a result of variation of the impedance, a current at the transmitter unit 106 varies. Accordingly, a communication between the transmitter unit 106 and the receiver unit 108 is established.
[0029] In another embodiment, the transmitter unit 106 is also configured to communicate with the receiver unit 108. Hence, a bidirectional communication between the transmitter unit 106 and the receiver unit 108 is desirable. Information is transmitted from the transmitter unit 106 to the receiver unit 108 by varying a frequency/amplitude of a voltage signal at the transmitter unit 106. In one example, the information transmitted from the transmitter unit 106 may be representative of power providing capability of the transmitter unit 106. In another example, the information transmitted from the transmitter unit 106 may be representative of an identification packet for the corresponding transmitter unit 106. Voltage signals at at least one of the alternating current terminals of the main converter 124 and plurality of auxiliary converters 126 is varied as a result of the variation of the frequency/amplitude of the voltage signal at the transmitter unit 106. Subsequently, the voltage signal at at least one of the alternating current terminals of the main converter 124 and plurality of auxiliary converters 126 is demodulated by a demodulator 136 of the communication subunit 130. Accordingly, the information transmitted from the transmitter unit 106 is interpreted at the receiver unit 108. Further, the demodulator 136 provides a demodulated signal to the controller 128 for subsequent action. In one embodiment, the demodulated signal is obtained by using techniques, such as but not limited to frequency and/or amplitude demodulation, frequency shift keying demodulation, and amplitude shift keying demodulation.
[0030] In one embodiment, when the receiver coil 116 is in alignment with the transmitter coil 114, the transmitter unit 106 provides power to the load. In particular, during operation of the wireless power transfer system 100, power provided from the power source 104 is converted from one form to another form by the transmitter drive subunit 112 and provided to the transmitter coil 114. More particularly, the low frequency or direct current (DC) power fed from the power source 104 is converted to a high frequency power by the transmitter drive subunit 112. Accordingly, the transmitter coil 114 is energized and a magnetic field is generated at the transmitter coil 114. The magnetic field at the transmitter coil 114 induces voltages at the main receiver coil 120 and the plurality of auxiliary receiver coils 122 based on alignment of the main receiver coil 120 and the plurality of auxiliary receiver coils 122 with respect to the transmitter coil 114. The combination of voltages induced at the main receiver coil 120 and the plurality of auxiliary receiver coils 122 is referred to as a first voltage.
[0031] The voltages induced at the main receiver coil 120 and the plurality of auxiliary receiver coils 122 are transmitted to the main converter 124 and the plurality of auxiliary converters 126, respectively. A rectified voltage is generated at the main output terminal of the main converter 124 and another rectified voltage is generated at the auxiliary output terminal of the plurality of auxiliary converters 126. In accordance with aspects of the present specification, a combination of the voltage obtained at the main output terminal and the voltage obtained at the auxiliary output terminal is provided to the load (not shown in FIG. 1). The combination of the voltages obtained at the main output terminal and the voltage obtained at the auxiliary output terminal is referred to as a second voltage.
[0032] Conventionally, switches and other electronics of a receiver unit are discrete electronic components soldered to a printed circuit board. Use of these discrete electronic components increases footprint of such a receiver unit. As a result, use of the receiver unit in compact devices, like mobile phones, laptops, and the like can be a challenge.
[0033] The above-mentioned drawbacks associated with the conventional receiver unit may be overcome by use of the exemplary integrated electronic component 117. In particular, the integrated electronic component 117 includes most of the electronics of the receiver unit 108. More particularly, the integrated electronic component 117 includes the first switches of the receiver drive subunit 118, the second switch of the communication subunit 130, the demodulator 136, connections between the first switches, connections between the communication subunit 130 and receiver drive subunit 118, formed on the substrate 132. In a similar manner, any other associated electronic switches of the receiver unit 108 may be formed on the substrate 132. In one embodiment, the substrate may be a thin silicon wafer. Further, the controller 128 is disposed on the substrate 132. Furthermore, the substrate 132 is packaged in a package unit 134 to provide externally extending connection pins.
[0034] The integrated electronic component 117 has a substantially lower footprint, thereby facilitating easy incorporation of the integrated electronic component 117 into compact devices such as the mobile phone, for example. Moreover, use of the integrated electronic component 117 facilitates to reduce effects of circuit parasitics, such as track impedance and associated voltage drop. Furthermore, use of the integrated electronic component 117 facilitates to enhance misalignment tolerance compared to use a conventional receiver drive subunit having discrete electronic components.
[0035] FIG. 2 is a schematic representation 200 of the receiver unit 108 of the wireless power transfer system 100 of FIG. 1 in accordance with an embodiment of the present specification. In the illustrated embodiment, the receiver unit 108 is coupled to a load 202. In one embodiment, the load 202 includes a battery pack or battery charger. The receiver unit 108 includes the receiver coil 116 and the integrated electronic component 117. The receiver coil 116 includes the main receiver coil 120 and two auxiliary receiver coils 122a, 122b. The main receiver coil 120 and the auxiliary receiver coils 122a, 122b are resonant coils. The main receiver coil 120 is coupled to a capacitor Crx1. Further, the auxiliary receiver coil 122a is coupled to a capacitor Ca1 and the auxiliary receiver coil 122b is coupled to another capacitor Ca2.
[0036] The integrated electronic component 117 includes the substrate 132, the receiver drive subunit 118, the controller 128, and the communication subunit 130. The receiver drive subunit 118 and the communication subunit 130 are formed on the substrate. Further, the controller 128 is disposed on the substrate. Further, the substrate 132 along with the receiver drive subunit 118, the controller 128, and the communication subunit 130 are disposed within a package unit (not shown in FIG. 2) to form a compact integrated electronic component 117. In one example, the substrate 132 along with the receiver drive subunit 118, the controller 128, and the communication subunit 130 are hermetically sealed in the package unit.
[0037] In the illustrated embodiment, the receiver drive subunit 118 includes the main converter 124 and a plurality of auxiliary converters 126a, 126b. The main receiver coil 120 is coupled to the main converter 124. The auxiliary receiver coil 122a is coupled to the auxiliary converter 126a and the other auxiliary receiver coil 122b is coupled to the auxiliary converter 126b. Further, an alternative switch 204 such as a diode is coupled across the auxiliary converters 126a, 126b. The alternative switch 204 may also be referred to as a third switch.
[0038] The main converter 124 includes the first switches 206. Further, the auxiliary converters 126a, 126b includes the first switches 208. In the illustrated embodiment, the first switches 206, 208 include a diode. In another embodiment, the first switches 206, 208 may include semiconductor switches such as an insulated gate bipolar transistor, a metal oxide semiconductor field effect transistor, a field-effect transistor, an injection enhanced gate transistor, an integrated gate commutated thyristor, a gallium nitride based switch, a silicon carbide based switch, a gallium arsenide based switch, or the like. Further, the main converter 124 and auxiliary converters 126a, 126b include a passive rectifier. In another embodiment, the main converter 124 and auxiliary converters 126a, 126b may include a hybrid rectifier and an active rectifier. The term ‘hybrid rectifier,’ as used herein, refers to a rectifier circuit having a combination of passive switches and active switches.
[0039] The main converter 124 includes the main output terminal 210. The auxiliary converter 126a is coupled in parallel to the auxiliary converter 126b to form an auxiliary output terminal 212. Further, the main output terminal 210 is coupled in series to the auxiliary output terminal 212 to form a common output terminal 214. Furthermore, the load 202 is coupled across the common output terminal 214.
[0040] Further, the main converter 124 includes an alternating current terminal 216 having two branches 216a, 216b. The auxiliary converter 126a includes an alternating current terminal 218 and the auxiliary converter 126b includes an alternating current terminal 220. The alternating current terminal 218 includes two branches 218a, 218b. Further, the alternating current terminal 220 include two branches 220a, 220b.
[0041] Further, the receiver unit 108 includes an output enable switch 228 formed on the substrate 132. Further, the receiver unit 108 includes capacitors C1 and Cdc coupled to the output enable switch 228. The capacitor C1 is coupled in parallel to the common output terminal 214. Furthermore, the load 202 is coupled parallel to the capacitor Cdc. It should be noted herein that the capacitors C1 and Cdc ¬and the load 202 do not form a part of the integrated electronic component 117.
[0042] Additionally, the receiver unit 108 includes a plurality of impedance components 230. For the ease of representation, the plurality of impedance components 230 are also represented as Z1, Z2, Z3, Z4, Z5, and Z6. The plurality of impedance components 230 are disposed external to the integrated electronic component 117.
[0043] The communication subunit 130 includes a plurality of second switches 222 coupled to each other. For ease of representation, the plurality of second switches 222 is also represented as S1, S2, S3, S4, S5, and S6. The plurality of second switches 222 includes semiconductor switches such as an insulated gate bipolar transistor, a metal oxide semiconductor field effect transistor, a field-effect transistor, an injection enhanced gate transistor, an integrated gate commutated thyristor, a gallium nitride based switch, a silicon carbide based switch, a gallium arsenide based switch, a diode, or the like.
[0044] Further, the communication subunit 130 is coupled to the alternating current terminals 216, 218, 220. In particular, the second switches 222 are coupled to the alternating current terminals 216, 218, 220 via the impedance components 230. More particularly, the switch S1 is coupled to the branch 216a via the impedance component Z1 and the switch S2 is coupled to the branch 216b via the impedance component Z2. Further, the switch S3 is coupled to the branch 218a via the impedance component Z3 and the switch S4 is coupled to the branch 218b via the impedance component Z4. Furthermore, the switch S5 is coupled to the branch 220a via the impedance component Z5 and the switch S6 is coupled to the branch 220b via the impedance component Z6.
[0045] The controller 128 is coupled to a current sensor 224 and a voltage sensor 226. In particular, the controller 128 is configured to determine circuit parameters such as value of current and voltage at the common output terminal 214. More particularly, the controller 128 is configured to receive the values of current at the common output terminal 214 measured by the current sensor 224. In another embodiment, the current sensor 224 can be located after the capacitor C1 in series with the switch 228. Further, the controller 128 is configured to receive the value of voltage at the common output terminal 214 measured by the voltage sensor 226. Further, the controller 128 is configured to activate and/or deactivate the output enable switch 228. Furthermore, the controller 128 is configured to activate and/or deactivate the second switches 222 of the communication subunit 130 based on the determined circuit parameters.
[0046] A method of manufacturing the electronic component 117 involves a first step of designing an electric circuit to be formed on the substrate 132. In the example of FIG. 2, the electrical circuit includes first switches 206, 208, connections between the first switches 206, 208, the second switches 222, connections between the second switches 222, connections between the first switches 206, 208 and the second switches 222, the output enable switch 228, the alternative switch 204, connection of the alternative switch 204 to the auxiliary output terminal 212, the connection of the output enable switch 228 to the common output terminal 214, and the demodulator 136.
[0047] At a second step, a circuit layout of the electrical circuit that needs to be disposed on the substrate 132 is designed using different tools such as Verilog, MATLAB, Simulink, VHDL, and the like. The circuit layout includes different patterns corresponding to different process layers such as a N+ diffusion layer, a P+ diffusion layer, a metal layer, a N-well layer, a contact cut layer, a polysilicon layer, and the like.
[0048] At a third step, a mask is manufactured for each of the process layers. For example, one mask may correspond to the N+ diffusion layer and another mask may correspond to the contact cut layer. In a similar manner, masks for other process layers are manufactured. It should be noted herein that a mask is formed by etching the pattern of each process layer on a corresponding glass sheet. A plurality of such masks corresponding to the process layers is produced.
[0049] Further, at a fourth step, each mask is used to develop a corresponding pattern on the substrate 132 using a photolithography technique to form a corresponding process layer. Accordingly, the process layers are developed on the substrate 132 to form the electrical circuit.
[0050] At a fifth step, the controller 128 is disposed on the substrate 132 at a designated location to establish connection to the second switches 222, the output enable switch 228, and the common output terminal 214. Subsequently, at a sixth step, the substrate 132 is disposed in the package unit 134 to provide exteriorly extending connection pins.
[0051] During operation of the wireless power transfer system 100, during an initial state, such as at a time instant t=0, the main receiver coil 120 or the auxiliary receiver coils 122a, 122b are powered by the transmitter coil 114. Further, at time t=0, the transmitter unit 106 may be configured to send ping signals to the receiver unit 108. In one embodiment, the ping signals may be a variation in power at the transmitter unit 106 which may cause a variation of the circuit parameters at the receiver unit 108. These circuit parameters may include the voltage/current/power at the common output terminal 214, in one example. Also, at the time instant t=0, the output enable switch 228 may be in a deactivated state.
[0052] Subsequently, for example, at a time instant t=t1, the receiver unit 108 acknowledges the ping signal sent from the transmitter unit 106. In particular, the receiver unit 108 may be configured to send an information having one or more bit patterns, such as a 11-bit pattern. In one embodiment, the bit patterns may be representative of the signal strength received by the receiver unit 108 and/or an identification information of the receiver unit 108. The ping signal sent from the transmitter unit 106 and the acknowledgement sent by the receiver unit 108 is indicative of the communication between the receiver unit 108 and the transmitter unit 106. Further, at the time instant t=t2, where t2> t1, the output enable switch 228 may be activated. The output enable switch 228 may be activated by providing a gate control signal to the output enable switch 228 by the controller 128.
[0053] Moreover, to enable communication between the transmitter unit 106 and the receiver unit 108, the controller 128 controls switching of the switches S1 and S2 based on the measurement of circuit parameters at the common output terminal 214. In particular, the controller 128 is configured to activate and/or deactivate the switches S1 and S2 by providing the corresponding gate control signal to the switches S1 and S2. In one embodiment, when the switch S1 is activated, the switch S2 is also activated. The impedance loading the main receiver coil 120, as seen by the transmitter unit 106 end varies based on activation and/or deactivation of the switches S1 and S2. As a result, the value of current at the transmitter unit 106 is varied. The variation of current at the transmitter unit 106 is in the form of the bit pattern is configured to provide information to the transmitter unit 106.
[0054] Information is representative of performance parameters of the receiver unit 108, in one example. This information is transmitted by the receiver unit 108 to the transmitter unit 106 at regular intervals. In particular, information representative of the type of connected load, an amount of power/voltage/current demanded by the load 202, control error, such as, a output voltage error are transmitted by the receiver unit 108. Accordingly, a controller at the transmitter unit 106 may be configured to regulate the power provided from the transmitter unit 106 to meet any demand of the load.
[0055] Furthermore, the switches S1 to S6 are switched synchronously. In one embodiment, the controller 128 controls switching of the switches S3 and S4 based on the measurement of circuit parameters at the common output terminal 214. The impedance loading the auxiliary receiver coil 122a, as seen from the transmitter unit 106 end is varied based on the switching of the switches S3 and S4. As a result, the value of current at the transmitter unit 106 is varied. The variation of current at the transmitter unit 106 is in a form of a bit pattern such as a 11-bit pattern configured to provide information to the transmitter unit 106. A controller of the transmitter unit 106 may be configured to regulate power provided from the transmitter unit 106 to meet a demand of the load 202. The combination of switches S1, S2, S3, S4, S5, and S6 which are coupled to the main receiver coil 120 and the auxiliary receiver coils 122a, 122b, facilitates to enhance communication between the receiver unit 108 and the transmitter unit 106 compared to an embodiment having only the switches S1 and S2.
[0056] In one embodiment, when the main receiver coil 120 is aligned with the transmitter coil 114, the auxiliary converters 126a, 126b may contribute a low value of voltage to the load 202. In such an embodiment, the alternative switch 204 provides a path for a flow of current to prevent flow of current through the auxiliary converters 126a, 126b. Accordingly, losses in the auxiliary converters 126a, 126b is avoided.
[0057] In certain other embodiments, if the transmitter unit 106 is supplying power but instead of the receiver coils 120, 122a, 122b a foreign object is in the vicinity of the transmitter unit 106, the foreign object may not communicate with the transmitter unit 106. Accordingly, the transmitter unit 106 does not provide power and thereby prevents localized heating at the location of the foreign object. The foreign object may be any metallic object, in one example.
[0058] In yet another embodiment, a foreign object in combination with at least one of the receiver coils 120, 122a, 122b may be drawing power from the transmitter unit 106. In such an embodiment, the presence of the foreign object is detected by comparing a value of power received at the receiver coils 120, 122a, or 122b with a value of power transmitted from the transmitter unit 106. If the difference between the value of the power transmitted from the transmitter unit 106 and the value of power received at the receiver coils 120, 122a, or 122b is higher than a determined threshold value, the presence of the foreign object is detected. Accordingly, the transmitter unit 106 terminates supply of power and thereby prevents localized heating at the location of the foreign object.
[0059] Although the embodiment of FIG. 2 shows auxiliary converters 126a, 126b coupled in parallel to each other, in other embodiments, the auxiliary converters 126a, 126b may also be coupled to each other in series. Further, although only two auxiliary receiver coils 120a, 120b and corresponding auxiliary converters 126a, 126b are represented, in other embodiments, a number of auxiliary receiver coils and corresponding auxiliary converters may vary depending on the application.
[0060] FIG. 3 is a schematic representation of one embodiment 300 of the receiver unit 108 of the wireless power transfer system 100 of FIG. 1 in accordance with an embodiment of the present specification. As discussed earlier, the receiver unit 108 is coupled to the load 202. The receiver unit 108 includes the receiver coil 116 and the integrated electronic component 117.
[0061] In the illustrated embodiment, the integrated electronic component 117 includes the substrate 132, the controller 128, and the communication subunit 130. Furthermore, the integrated electronic component 117 includes a diode 302 and the output enable switch 228. In the example of FIG. 3, the communication subunit 130 is operatively coupled to the common output terminal 214. In one embodiment, the second switch 222 of the communication subunit 130 is operatively coupled to the common output terminal 214 via the corresponding impedance component 230.
[0062] As discussed earlier, the controller 128 is configured to measure the circuit parameters such as voltage, current, and/or power of the common output terminal 214. The controller 128 is configured to control activation and/or deactivation of the second switch 222 based on the measured circuit parameters. Further, the controller 128 is configured to control activation and/or deactivation of the output enable switch 228.
[0063] In one embodiment, the integrated electronic component 117 is an integrated circuit. In one embodiment, the integrated circuit is an application specific integrated circuit (ASIC). The integrated electronic component 117 is packaged in such a manner to provide externally extending connection pins. In the illustrated embodiment, the connections pins may be available at locations X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11. The external components such as the receiver coils 120, 122a, 122b, the impedance component 230, and the load 202 may be coupled to the connections pins at the locations X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11. Further, the integrated electronic component 117 may include additional connection pins for connecting to other external electrical/electronic components (not disclosed herein).
[0064] During operation of the wireless power transfer system 100, at the time instant time t=0, the receiver unit 108 is powered by the transmitter unit 106. Further, at time t=0, the transmitter unit 106 may be configured to send ping signals to the receiver unit 108. The receiver unit 108 acknowledges the ping signals sent from the transmitter unit 106. The controller 128 activates the output enable switch 228 subsequent to the acknowledgement by the receiver unit 108.
[0065] In order to communicate from the receiver unit 108 to the transmitter unit 106, the controller 128 may activate or deactivate the second switch 222. When the second switch 222 is activated, the impedance component 230 is connected across the common output terminal 214. As a result, the impedance loading the receiver coils 120, 122a, 122b, as seen by the transmitter unit 106, varies. As a result of variation of impedance, a current at the transmitter coil 114 may vary in such a manner that a 11-bit pattern is obtained at the transmitter unit 106. Accordingly, information is transmitted from the receiver unit 108 to the transmitter unit 106. The information may be representative of the value of power or a control error that needs to be provided to the load 202. Once the information is received at the transmitter unit 106, the power/voltage/current/frequency at the transmitter unit 106 is controlled by the controller 128.
[0066] As noted hereinabove, when the second switch 222 is activated, the impedance component 230 is connected across the common output terminal 214. If the diode 302 is not present, activation of the second switch 222 also provides one closed path via the second switch 222, the impedance component 230, the output enable switch 228, the capacitor Cdc, and back to the second switch 222. Further, another closed path is provided via the second switch 222, the impedance component 230, the capacitor C1, and back to the second switch 222. In such a scenario, the capacitors C1 and Cdc may discharge via the corresponding closed paths.
[0067] The capacitor Cdc is a load capacitor. The discharge of the capacitor Cdc results in loss of stored energy at a load terminal. In one example, the load terminal includes input terminals of a charger stage of a battery of a mobile phone. Hence, the discharge of the capacitor Cdc needs to be prevented. Further, C1 is the capacitor across which the circuit parameters of the common output terminal 214 are measured by the controller 128. The discharge of the capacitor C1 may cause an undesirable variation in the voltage across the capacitor C1. The variation in voltage across the capacitor C1 may cause inaccurate measurement of circuit parameters at the common output terminal. Hence, the discharge of the capacitor C1 needs to be prevented.
[0068] In order to avoid discharge of the capacitors C1 and Cdc, the diode 302 is employed. The use of the diode 302 blocks the flow of current from the capacitors C1 and Cdc. As a result, the discharge of the capacitors C1 and Cdc is prevented.
[0069] FIG. 4 is a schematic representation of another embodiment 400 of the receiver unit 108 of the wireless power transfer system 100 of FIG. 1 in accordance with an embodiment of the present specification. As discussed earlier, the receiver unit 108 is coupled to the load 202. The receiver unit 108 includes the main receiver coil 120, the auxiliary receiver coils 122a, 122b, and the integrated electronic component 117. The integrated electronic component 117 includes the substrate 132, the main converter 124, the auxiliary converters 126a, 126b, the controller 128, the communication subunit 130, and the output enable switch 228.
[0070] The communication subunit 130 includes switches 404, 408, and a NOT logical gate 406. The switch 404 may be alternatively referred to as a second switch. A gate signal is provided to a gate terminal of the switch 404. This gate signal is inverted using the NOT logical gate 406 and an inverted gate signal is provided to a gate terminal of the switch 408. The activation/deactivation of the switches 404, 408 is determined based on the gate signals at the gate terminals of the switches 404, 408. In one embodiment, when the gate signals corresponding to the switches 404, 408 are high, the switches 404, 408 are configured to be activated. In another embodiment, when the gate signals corresponding to the switches 404, 408 are low, the switches 404, 408 are configured to be deactivated.
[0071] The receiver unit 108 further includes an impedance component 402. The impedance component 402 is disposed externally to the integrated electronic component 117. Further, the receiver unit 108 includes a capacitor C1 coupled across the common output terminal 214. Furthermore, the capacitor Cdc is coupled across the load 202. The output enable switch 228 is coupled to the capacitors C1 and Cdc. The capacitors C1 and Cdc are also disposed externally to the integrated electronic component 117.
[0072] During operation of the receiver unit 108, at least one of the auxiliary receiver coils 122a, 122b or main receiver coil 120 is powered by the transmitter coil 114. Subsequently, the output enable switch 228 is activated based on the communication between the transmitter unit 106 and the receiver unit 108. Further, the controller 128 measures the circuit parameters at the common output terminal 214. Furthermore, the controller 128 controls operation of the communication subunit 130 based on the measured circuit parameters. In particular, the controller 128 controls operations of the switch 404 based on the measured circuit parameters. Accordingly, the switch 404 is activated and/or deactivated. When the switch 404 is activated, the impedance component 402 is coupled across the common output terminal 214. Accordingly, the impedance loading the receiver coils 120, 122a, 122b as seen from the transmitter unit 106 end changes. The change in impedance is reflected as a change in current at the transmitter unit 106.
[0073] As a result of activation and/or deactivation of the switch 404, the current at the transmitter coil 114 is varied in such a manner that a bit pattern is obtained at the transmitter unit 106. Accordingly, the information is transmitted from the receiver unit 108 to the transmitter unit 106.
[0074] It may be noted that if both the switches 404 and 408 are activated at same period of time, a closed path is formed via the switch 404, the impedance component 402, the switch 408, the output enable switch 228, the capacitor Cdc, and back to the switch 404. As a result, the capacitor Cdc may discharge via the switch 408, the impedance component 402, and the switch 404. In a similar manner, the capacitor C1 may be discharged. In order to avoid discharge of the capacitors C1 and Cdc, the switch 408 has to be deactivated. According to aspects of the present specification, when the switch 404 is activated, the switch 408 is deactivated. The gate signal provided at the gate terminal of the switch 404 is inverted by the NOT logic gate 406 and provided to the gate terminal of the switch 408. Accordingly, the switch 408 is deactivated. As a result of deactivation of the switch 408, the capacitors C1 and Cdc are disconnected from the common output terminal 214, thereby preventing discharge of the capacitors C1 and Cdc.
[0075] Further, the controller 128 measures circuit parameters at the alternating current terminal 216 of the main converter 124 and the alternating current terminals 218, 220 of the auxiliary converters 126a, 126b respectively. The controller 128 further determines pattern of switching of first switches 410 of the main converter 124 based on circuit parameters at the alternating current terminal 216 of the main converter 124. Further, the controller 128 determines the pattern of switching of first switches 412 of the auxiliary converters 126a, 126b based on the circuit parameters corresponding to the alternating current terminals 218, 220 of the auxiliary converters 126a, 126b. The term “pattern of switching,” as used herein, may refer to pattern of activating/deactivating the first switches 412. Although the example of FIG. 4 refers to use of the controller 128 to switch the first switches 410, 412, use of a separate controller for switching the first switches 410, 412 is also envisioned.
[0076] FIG. 5 is a schematic representation of the receiver coil 120 of the wireless power transfer system 100 of FIG. 1 in accordance with an embodiment of the present specification. In particular, FIG. 5 is a top view of the receiver coil 116. The receiver coil 116 includes the main receiver coil 120 and plurality of auxiliary receiver coils 122a, 122b, 122c, 122d.
[0077] Reference numeral 502 is representative of a central axis of the main receiver coil 120. The central axis 502 is referred to as an axis passing through a center and perpendicular to a x-y plane of the main receiver coil 120.
[0078] In the illustrated embodiment, the main receiver coil 120 is disposed directly on a ferrite layer 504. According to aspects of the present specification, the plurality of auxiliary receiver coils 122a, 122b, 122c, 122d is disposed about the central axis 502. In the illustrated embodiment, four auxiliary receiver coils 122 are disposed about the main receiver coil 120. The number of auxiliary receiver coils may vary depending on the application.
[0079] In accordance with the embodiments discussed herein, the arrangement of the main receiver coil, the plurality of auxiliary receiver coils, and the corresponding converters facilitate efficient power transfer between the transmitter coil and the receiver coils even in the event of a misalignment of the main receiver coil with respect to the transmitter coil. Further, the main converter, the auxiliary converters, and other related electronics of the receiver unit are formed on a substrate to form an integrated electronic component. Accordingly, the footprint of the corresponding electronics of the receiver unit is considerably reduced.
[0080] While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof.