# US 2014/0191818 A1 · Dynamic resonant matching circuit for wireless power receivers

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- Number: US 2014/0191818 A1
- Document ID: US20140191818A1
- Status: Published application
- Kind: A1
- Application number: 14/238,854
- Filed: 2012-08-06
- Published: 2014-07-10
- Earliest claimed: 2011-08-16
- Assignees: Koninklijke Philips N.V.
- Inventors: Eberhard Waffenschmidt; Adrianus Sempel; Dave Willem Van Goor; Henricus Theodorus Van Der Zanden
- Web page: https://patentgrep.com/patent/US20140191818A1

## CPC

- H04B 5/22: Capacitive coupling
- H01F 38/14: Inductive couplings
- H01P 1/10: for switching or interrupting {(in systems using reflection or reradiation of radio, acoustic or other waves G01S7/034)}
- H02J 50/05: using capacitive coupling
- H02J 50/10: using inductive coupling
- H02J 50/12: of the resonant type
- H03H 7/38: Impedance-matching networks
- H03J 1/00: Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general
- H04B 5/79: for data transfer in combination with power transfer
- H04B 5/24: Inductive coupling
- H04B: TRANSMISSION
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B)
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)
- H03J: TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS

## Abstract

A resonant matching circuit (310) for matching a resonant frequency of a wireless power transfer system to a frequency of a power signal comprises a switch (311) connected in parallel with a resonant element (302) of the wireless power transfer N system; and a controller (312) connected to the switch (311) and configured to detect a zero-voltage level crossing of a signal flowing through the resonant element (302) and to close the switch (311) for a predefined amount of time upon detection of the zero-voltage level crossing, wherein closing the switch (311) for the predefined amount of time adds any one of an inductive value and a capacitive value to the resonant frequency of a wireless power transfer system.

## Claims

### Claim 1

A resonant matching circuit for matching a resonant frequency of a wireless power transfer system to a frequency of a power signal, comprising:
a switch connected in parallel with a resonant element of the wireless power transfer system; and
a controller connected to the switch and configured to detect a zero-voltage level crossing of a signal flowing through the resonant element and to close the switch for a predefined amount of time upon detection of the zero-voltage level crossing, wherein closing the switch for the predefined amount of time adds any one of an inductive value and a capacitive value to the resonant frequency of a wireless power transfer system.

### Claim 2 (depends on 1)

The circuit of claim 1, wherein the s itch is closed immediately prior to the zero-voltage level crossing or immediately after the zero-voltage level crossing.

### Claim 3 (depends on 1)

The circuit of claim 1, wherein the predefined amount of time is less than half of the period of the frequency of the power signal.

### Claim 4 (depends on 1)

The circuit of claim 1, wherein the wireless power transfer system is any one of a capacitive power transfer system and an inductive power transfer system.

### Claim 5

A resonant matching circuit for matching a resonant frequency of a wireless power transfer system to a frequency of a power signal, comprising:
a switch connected in series with a resonant element of the wireless power transfer system; and
a controller connected to the switch and configured to detect crossing of a zero current level of a signal flowing through the resonant element and to open the switch for a predefined amount of time upon detection of the zero current level crossing, wherein opening the switch for the predefined amount of time adds any one of an inductive value and a capacitive value to the resonant frequency of a wireless power transfer system.

### Claim 6 (depends on 5)

The circuit of claim 5, wherein the switch is opened immediately prior to the zero current level crossing or immediately after the zero current level crossing.

### Claim 7 (depends on 5)

The circuit of claim 5, wherein the predefined amount of time is less than half of the period of the frequency of the power signal.

### Claim 8 (depends on 5)

The circuit of claim 5, wherein the wireless power transfer system is any one of a capacitive power transfer system and an inductive power transfer system.

### Claim 9

A resonant matching circuit for matching a resonant frequency of a capacitive power transfer system to a frequency of a power signal, comprising:
a switch connected in series with an inductive element of the capacitive power transfer system; and
a controller connected to the switch and configured to detect crossing of a zero current level of a signal flowing through the inductive element and to open the switch for a predefined amount of time upon detection of the zero current level crossing, wherein opening the switch for the predefined amount of time adds any one of an inductive value and a capacitive value to the resonant frequency of the capacitive power transfer system, wherein the resonant frequency is a function of the inductive element, a capacitive impedance formed between receiver electrodes and transmitter electrodes of the capacitive power transfer system, and any one of the inductive value and the capacitive value.

### Claim 10 (depends on 9)

The circuit of claim 9, wherein the predefined amount of time is less than half of the period of the frequency of the power signal.

### Claim 11

A resonant matching circuit for matching a resonant frequency of a capacitive power transfer system to a frequency of a power signal, comprising:
a switch connected in parallel with an inductive element of the capacitive power transfer system; and
a controller connected to the switch and configured to detect crossing of a zero voltage level of a signal flowing through the inductive element and to close the switch for a predefined amount of time upon detection of the zero voltage level crossing, wherein dosing the switch for the predefined amount of time adds any one of an inductive value and a capacitive value to the resonant frequency of a wireless power system, wherein the resonant frequency is a function of the inductive element, a capacitive impedance formed between receiver electrodes and transmitter electrodes of the capacitive power transfer system, and any one of the inductive value and the capacitive value.

### Claim 12 (depends on 11)

The circuit of claim 11, wherein the predefined amount of time is less than half of the period of the frequency of the power signal.

### Claim 13 (depends on 11)

The circuit as in claim 11, wherein the switching operation of the switch is performed by an active rectifier.

### Claim 14 (depends on 11)

The circuit as in claim 11, wherein the wireless power transfer system includes a plurality of receivers, wherein a resonant matching circuit is connected to each receiver of the plurality of receivers to independently match the resonant frequency of the receiver.

### Claim 15 (depends on 11)

The circuit as in claim 11, wherein the switch is further configured to modulate a data signal over the power signal.