US 10,476,313 B2Granted

Foreign object detection in a wireless power transfer system

AssigneeDenso Corporation

InventorsTrong Duy Nguyen, Christopher Jeffery White

Life of this patent

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Abstract

A wireless power transfer system includes a transmitter with a transmitting coil, a first detection coil, and a second detection coil. The transmitting coil receives and wirelessly radiates power from a power supply to a receiver of a vehicle. In response to the radiated power from the transmitting coil, the first detection coil generates a first voltage, and the second detection coil generates a second voltage. A comparison system is electrically coupled to the transmitter. The comparison system declares presence of a foreign object in proximity to the transmitter in response to a difference between the first voltage and a first reference voltage exceeding a threshold value. The comparison system declares the presence of the foreign object in response to a difference between the second voltage and a second reference voltage exceeding the threshold value. The transmitter is selectively disabled in response to presence of the foreign object being declared.

Claims14

Dependent claims

A wireless power transfer system comprising:

a transmitter that includes a transmitting coil, a first detection coil, and a second detection coil, wherein:
the transmitting coil is configured to receive and wirelessly radiate power from a power supply to a receiver of a vehicle;
the first detection coil is configured to generate a first voltage in response to the radiated power from the transmitting coil;
and
the second detection coil is configured to generate a second voltage in response to the radiated power from the transmitting coil;
and
a comparison system electrically coupled to the transmitter,
wherein the comparison system includes a microcontroller configured to, by instructions stored in non-transitory memory:
calculate a difference between the first voltage and a first reference voltage;
calculate a difference between the second voltage and a second reference voltage;
generate a first logic signal in response to the difference between the first voltage and the first reference voltage exceeding a threshold value;
and
generate a second logic signal in response to the difference between the second voltage and the second reference voltage exceeding the threshold value;
wherein the comparison system includes (i) a first differential operational amplifier configured to output a first signal based on the difference between the first voltage and the first reference voltage and (ii) a second differential operational amplifier configured to output a second signal based on the difference between the second voltage and the second reference voltage;
wherein the comparison system is configured to declare presence of a foreign object in proximity to the transmitter in response to one of (i) the first logic signal being generated, (ii) the second logic signal being generated, (iii) the first signal being outputted, and (iv) the second signal being outputted;
and
wherein the transmitter is selectively disabled in response to presence of the foreign object being declared.

14 more elements

A wireless power transfer method comprising:

receiving and wirelessly radiating power, with a transmitting coil of a transmitter, from a power supply to a receiver of a vehicle;
generating, with a first detection coil of the transmitter, a first voltage in response to the radiated power from the transmitting coil;
generating, with a second detection coil of the transmitter, a second voltage in response to the radiated power from the transmitting coil;
calculating, using a microcontroller of a comparison system electrically coupled to the transmitter, a difference between the first voltage and a first reference voltage, wherein the microcontroller is configured to execute instructions stored in non-transitory memory;
calculating, using the microcontroller, a difference between the second voltage and a second reference voltage, the comparison system including (i) a first differential operational amplifier configured to output a first signal based on the difference between the first voltage and the first reference voltage and (ii) a second differential operational amplifier configured to output a second signal based on the difference between the second voltage and the second reference voltage;
generating, using the microcontroller, a first logic signal in response to the difference between the first voltage and the first reference voltage exceeding a threshold value;
and
generating, using the microcontroller, a second logic signal in response to the difference between the second voltage and the second reference voltage exceeding the threshold value;
declaring, with the comparison system, presence of a foreign object in proximity to the transmitter in response to one of (i) the first logic signal being generated, (ii) the second logic signal being generated, (iii) the first signal being outputted, and (iv) the second signal being outputted;
and
disabling the transmitter in response to presence of the foreign object being declared.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/416,443Filed 26 Jan 2017
Published: US 2018/0212476 A126 Jul 2018
Granted: 12 Nov 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification14 codes

H02J 50/60
Circuit arrangements or systems for wireless supply or distribution of electric power: responsive to the presence of foreign objects, e.g.…
B60L 53/124
Inductive energy transfer: detection or removal of foreign bodies
H01F 38/14
Adaptations of transformers or inductances for specific applications or functions: inductive couplings
H02J 50/10
Circuit arrangements or systems for wireless supply or distribution of electric power: using inductive coupling