Wireless Power Transfer Control With Two-Phase Foreign Object Detection

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Solution Overview

Problem

Existing wireless charging technologies face challenges in accurately detecting foreign objects, leading to reduced efficiency, overheating, and potential damage due to foreign objects in the charging area, and unnecessary stopping of charging processes.

Innovation Solution

A method and apparatus for controlling wireless power transmission that includes multiple determination phases to accurately detect foreign objects by measuring power loss and temperature changes, allowing adaptive power control to prevent damage and ensure seamless charging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If foreign object detection is performed using existing wireless charging technologies, then charging efficiency is improved, but false detection occurs leading to unnecessary stopping of charging processes

Engineering Contradiction:
Improveforeign object detection accuracyVSAvoidcharging process continuity
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The foreign object detection process is divided into two distinct phases: a first determination phase that performs initial detection, and a second determination phase that performs verification detection. This segmentation allows the system to distinguish between actual foreign objects and false detections, maintaining charging continuity while improving detection accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first determination phase performs preliminary foreign object detection before the second determination phase. By conducting an initial assessment and then verifying with a second detection phase, the system prepares and confirms detection results in advance, reducing false positives and unnecessary charging interruptions.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If foreign object detection sensitivity is increased to prevent damage, then device safety is improved, but charging efficiency decreases due to more frequent false alarms

Engineering Contradiction:
Improvedevice safetyVSAvoidcharging efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The detection process is segmented into two phases with different sensitivity levels. The first determination phase uses higher sensitivity for initial detection, while the second determination phase provides verification. This segmentation allows the system to maintain high safety standards without suffering from continuous false alarms that would reduce charging efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses feedback from the first determination phase to adjust the operation in the second determination phase. If the first phase detects a potential foreign object, the second phase verifies it with appropriate sensitivity adjustment. This feedback mechanism ensures device safety while minimizing false alarms that would waste energy and reduce charging efficiency.

Inventive Principle:
Principle #23Feedback

3Device complexity

If single-phase foreign object detection is used, then device complexity is reduced, but detection accuracy decreases leading to false positives

Engineering Contradiction:
Improvedetection process simplicityVSAvoidforeign object detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The detection process is divided into two determination phases rather than using a single-phase approach. This segmentation increases detection accuracy by allowing verification of initial detections, reducing false positives while maintaining manageable system complexity through a structured two-phase process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first determination phase performs preliminary detection to identify potential foreign objects, and the second determination phase performs verification. This preliminary action followed by verification improves detection accuracy without significantly increasing overall system complexity, as the two phases build upon each other in a logical sequence.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances foreign object detection accuracy, prevents device damage, and ensures seamless charging by dynamically adjusting power transmission based on the presence of foreign objects.

Implementation Method 1

Wireless power transmission or wireless energy transfer technology refers to technology of wirelessly transmitting electric energy from a transmitter to a receiver using the principle of magnetic induction

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A foreign object detecting circuit measures an amount of change of the impedance value of a coil with respect to a change in the combined magnetic field in the case of the presence of a foreign object

Methodology Applied
Scientific EffectMagnetic field measurement: Magnetic Field

Data Source

PatentEP3796519B1Wireless power transmission control method and apparatus
Publication Date: 2026.03.11 LG INNOTEK CO LTD
  • EP3796519B1 patent drawingFigure 1~2
  • EP3796519B1 patent drawingFigure 3~4
  • EP3796519B1 patent drawingFigure 5

AI summary

Disclosed are a method of controlling wireless power transmission and an apparatus therefor. A method of controlling wireless power transmission of a wireless power transmitter includes a first packet reception phase of receiving a foreign object detection status packet, a first determination phase of determining whether the foreign object is present based on the foreign object detection status packet, and a power control phase of controlling power based on a determination result of the first determination phase, wherein the power control phase includes a first power transfer mode for transmitting first power upon determining that the foreign object is present as the determination result of the first determination phase, and a second power transfer mode for transmitting second power upon determining that the foreign object is not present as the determination result of the first determination phase.