Wireless Charging Safety: Early Foreign Substance Detection
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Summary
Problems
Existing wireless charging devices face challenges in detecting conductive foreign substances on the placement surface before the charging target is placed, leading to delayed detection and safety concerns due to prolonged power suppression.
Innovation solutions
A charging device equipped with a power transmission coil, a position detection coil, a foreign substance detection coil, a memory, and a processor that supplies electric power to a first coil of the foreign substance detection coil when the charging target is not placed, determining the presence of conductive foreign substances based on the variation of induced voltage in the position detection coil.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If the charging device uses echo signal from the charging target to detect conductive foreign substances, then detection can be performed using existing resonance circuit techniques, but detection cannot be performed when the charging target is not placed on the placement surface and it takes time to detect foreign substances even when the target is placed
Why choose this principle:
The system performs foreign substance detection before charging starts by detecting changes in the impedance of the power transmission coil when a conductive foreign substance is present on the placement surface. This preliminary detection occurs even when no charging target is placed, allowing the system to identify foreign substances in advance and prevent delayed detection during charging operation.
Principle concept:
If the charging device uses echo signal from the charging target to detect conductive foreign substances, then detection can be performed using existing resonance circuit techniques, but detection cannot be performed when the charging target is not placed on the placement surface and it takes time to detect foreign substances even when the target is placed
Why choose this principle:
The patent uses the power transmission coil's impedance characteristics as an intermediary indicator to detect foreign substances. Instead of directly detecting foreign substances or relying on echo signals from the charging target, the system measures impedance changes in the power transmission coil caused by the presence of conductive foreign materials, providing an indirect but effective detection method.
Application Domain
Data Source
AI summary:
A charging device equipped with a power transmission coil, a position detection coil, a foreign substance detection coil, a memory, and a processor that supplies electric power to a first coil of the foreign substance detection coil when the charging target is not placed, determining the presence of conductive foreign substances based on the variation of induced voltage in the position detection coil.
Abstract
A charging device includes: a power transmission coil configured to transmit electric power to a terminal device; a position detection coil that includes a plurality of coils, and is configured to detect a position of a power reception coil of the terminal device; a foreign substance detection coil that includes a plurality of coils corresponding to the plurality of coils of the position detection coil; and a processor configured to supply electric power to a first coil among the plurality of coils of the foreign substance detection coil in a state in which the terminal device is not placed on a placement part, to determine that a conductive foreign substance is present on the placement part in a case in which a variation amount of induced voltage generated in the position detection coil is equal to or larger than a predetermined threshold.