CONTACTLESS POWER SUPPLY DEVICE AND CONTACTLESS CHARGING SYSTEM
First Claim
1. A contactless power supply device that supplies power in a contactless manner from a primary coil to a secondary coil, the contactless power supply device comprising:
- the primary coil supplied with AC current l to generate alternating flux;
an input current measurement unit that measures a current value of an input current of the primary coil in a charging state during which the alternating flux generated by the primary coil intersects the secondary coil; and
a determination unit that determines that a metal foreign object has been detected when a most recent input current measured by the input current measurement unit in a most recent detection cycle is greater than or equal to a threshold obtained by adding a predetermined current value to a reference current value, which corresponds to a current value of an input current measured by the input current measurement unit in a previous detection cycle.
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Accused Products
Abstract
A primary-side controller (12) retains a reference current value corresponding to an input current measured in the previous detection cycle by an input current measurement unit (11), in a charging state. The primary-side controller (12) adds the retained reference current value and a predetermined current value, and generates a first threshold value. When the input current measured by the input current measurement unit (11) in the latest detection cycle is equal to or greater than the first threshold value, a determination is made that a foreign metal is present in the vicinity of a first coil (L1).
65 Citations
8 Claims
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1. A contactless power supply device that supplies power in a contactless manner from a primary coil to a secondary coil, the contactless power supply device comprising:
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the primary coil supplied with AC current l to generate alternating flux; an input current measurement unit that measures a current value of an input current of the primary coil in a charging state during which the alternating flux generated by the primary coil intersects the secondary coil; and a determination unit that determines that a metal foreign object has been detected when a most recent input current measured by the input current measurement unit in a most recent detection cycle is greater than or equal to a threshold obtained by adding a predetermined current value to a reference current value, which corresponds to a current value of an input current measured by the input current measurement unit in a previous detection cycle. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A contactless charging system comprising:
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a contactless power supply device including a primary coil supplied with AC current to generate alternating flux; and a contactless power reception device including a secondary coil that intersects the alternating flux generated by the primary coil, a conversion unit that converts AC current, which is supplied from the primary coil via the secondary coil, into DC current, and a load supplied with the DC current converted by the conversion unit, wherein the contactless power supply device includes an input current measurement unit that measures a current value of an input current of the primary coil in a charging state during which the alternating flux generated by the primary coil intersects the secondary coil, and a determination unit that determines that a metal foreign object has been detected when a most recent input current measured by the input current measurement unit in a most recent detection cycle is greater than or equal to a threshold obtained by adding a predetermined current value to a reference current value, which corresponds to a current value of an input current measured by the input current measurement unit in a previous detection cycle, and the contactless power reception device includes a load current control unit that constant-current-controls a load current converted to DC current by the conversion unit, a charging current control unit that supplies the load with the load current as charging current, and a power reception side measurement unit that measures a current value of the charging current, wherein the load current control unit is configured to constant-current-control the load current so that a current value of the load current becomes lower than the current value of the charging current, and the determination unit performs a determination when the load current control unit is executing constant current control. - View Dependent Claims (8)
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Specification