Rectifiers for Wireless Power Transfer with Impedance Inverting Filters for Reduced Electromagnetic Interference
First Claim
1. A receive circuit for wireless transfer of power, comprising:
- a receive coupler including a resonant circuit including;
a receive inductor; and
a first capacitor through which the receive inductor is connected to a first node;
a first pi filter connected between the first node and an intermediate node, including a second capacitance connected between the first node and ground, a third capacitance connected between the intermediate node and ground, and a first inductance connected between the first node and the intermediate node, wherein impedances of the second capacitance, the third capacitance, and the first inductance are formed to provide a first impedance inversion function for the first pi filter whereby impedance at the first node varies inversely with impedance at the intermediate node in a first frequency band;
a second pi filter connected between the intermediate node and a second node, including a fourth capacitance connected between the intermediate node and ground, a fifth capacitance connected between the second node and ground, and a second inductance connected between the intermediate node and the second node, wherein impedances of the fourth capacitance, the fifth capacitance, and the second inductance are formed to provide a second impedance inversion function for the second pi filter whereby impedance at the intermediate node varies inversely with impedance at the second node in the first frequency band; and
a rectifier through which the second node is connectable to drive a load.
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Accused Products
Abstract
Resonant rectifier topologies are described for tuning the rectifier so that it performs from an electromagnetic interference (EMI) point of view, while maintaining the voltage regulation at the output that a series tuned rectifier would maintain. Examples include a an inductor of a receive coupler and a rectifier connectable to drive a load, along with first and second filter elements that are each configured to provide an impedance inversion function in a frequency band and that are connected in series between the inductor of a receive coupler and rectifier. In one set of examples, both filter elements are implemented as pair filters, while in other examples the first filter element includes the inductor of a receive coupler in parallel with a capacitance connected to ground.
32 Citations
26 Claims
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1. A receive circuit for wireless transfer of power, comprising:
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a receive coupler including a resonant circuit including; a receive inductor; and a first capacitor through which the receive inductor is connected to a first node; a first pi filter connected between the first node and an intermediate node, including a second capacitance connected between the first node and ground, a third capacitance connected between the intermediate node and ground, and a first inductance connected between the first node and the intermediate node, wherein impedances of the second capacitance, the third capacitance, and the first inductance are formed to provide a first impedance inversion function for the first pi filter whereby impedance at the first node varies inversely with impedance at the intermediate node in a first frequency band; a second pi filter connected between the intermediate node and a second node, including a fourth capacitance connected between the intermediate node and ground, a fifth capacitance connected between the second node and ground, and a second inductance connected between the intermediate node and the second node, wherein impedances of the fourth capacitance, the fifth capacitance, and the second inductance are formed to provide a second impedance inversion function for the second pi filter whereby impedance at the intermediate node varies inversely with impedance at the second node in the first frequency band; and a rectifier through which the second node is connectable to drive a load. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A receive circuit for wireless transfer of power, comprising:
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a receive coupler including a first receive inductor connected to a first node; a first capacitance connected between the first node and ground, wherein the first receive inductor and the first capacitance are formed to have substantially equal but opposite reactances in a first frequency band; a first pi filter connected between the first node and a second node, including a second capacitance connected between the first node and ground, a third capacitance connected between the second node and ground, and a first inductance connected between the first node and the second node, wherein impedances of the second capacitance, the third capacitance, and the first inductance are formed to provide an impedance inversion function for the first pi filter whereby impedance at the first node varies inversely with impedance at the second node in the first frequency band; and a rectifier through which the second node is connectable to drive a load. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A receive circuit for wireless transfer of power, comprising:
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a receive coupler configured to wirelessly couple power via a wireless field, the receive coupler including a receive inductor; a rectifier connectable to drive a load; first filtering means configured to provide a first impedance inversion function in a first frequency band; and second filtering means configured to provide a second impedance inversion function in the first frequency band, where the receive inductor is connected to the rectifier through the first and second filtering means connected in series. - View Dependent Claims (24, 25)
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26. A receive circuit for wireless transfer of power, comprising:
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a receive coupler configured to inductively receive power via a magnetic field that has a frequency, the receive coupler including a resonant circuit that includes an inductive loop electrically coupled in series to a capacitive element, the resonant circuit configured to resonate at the frequency of the magnetic field; a rectifier electrically coupled to the receive coupler and configured to provide an output to power or charge a load; a first filter circuit electrically coupled between the receive coupler and the rectifier; and a second filter circuit electrically coupled between the first filter circuit and the rectifier, wherein the first filter circuit has one or more first reactive elements with values whereby impedance of the first filter circuit as seen at the receive coupler varies inversely with impedance of the second filter circuit, and the second filter circuit has one or more second reactive elements with values whereby impedance of the second filter circuit as seen at the first filter varies inversely with impedance of the rectifier.
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Specification