Wireless Power Coil State Detection for Foreign Object vs Misalignment

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing wireless power transmission systems struggle to distinguish between the presence of foreign objects and coil misalignment, leading to potential damage or inefficiencies in power transfer.

Innovation Solution

A wireless power transmitter equipped with a primary coil and a controller that communicates with the receiver to differentiate between the presence of foreign objects and coil misalignment using first and second information from the secondary coil, enabling precise control of power transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If wireless power transmission is performed using magnetic coupling, then power can be transferred wirelessly to provide mobility and convenience, but the system cannot distinguish between foreign objects and coil misalignment leading to potential damage or inefficiencies

Engineering Contradiction:
Improvewireless power transferVSAvoidforeign object detection accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent segments the detection function into multiple independent components: a first sensor detects transmission coil voltage to identify foreign objects, while a second sensor detects coil alignment status. This segmentation allows each sensor to specialize in detecting specific conditions, improving overall detection accuracy and reliability by separating the detection of foreign objects from misalignment detection.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the system transmits power without accurate differentiation between foreign objects and misalignment, then power transfer continues uninterrupted, but potential damage or inefficiencies occur

Engineering Contradiction:
Improvepower transfer continuityVSAvoidpower transfer damage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback control mechanism where the controller continuously receives detection results from both sensors and adjusts power transmission accordingly. When the first sensor detects a foreign object or the second sensor detects misalignment, the controller provides feedback to stop or adjust power transmission, preventing damage while maintaining continuous operation under normal conditions.

Inventive Principle:
Principle #23Feedback

3Device complexity

If the system uses simple foreign object detection methods, then the system remains simple, but it cannot differentiate between foreign objects and coil misalignment

Engineering Contradiction:
Improvedetection systemVSAvoidstate differentiation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by assigning different detection capabilities to different parts of the system. The first sensor is specifically designed and positioned to detect foreign objects near the transmission coil, while the second sensor is configured to detect coil alignment status. This localized specialization of detection functions improves measurement precision without requiring a single complex detection system.

Inventive Principle:
Principle #3Local quality

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

Enables accurate differentiation between foreign objects and coil misalignment, ensuring safe and efficient power transfer by adjusting power transmission accordingly.

Implementation Method 1

a power converter including a primary coil that is magnetically coupled to a secondary coil of the wireless power receiver and transmits the wireless power

Methodology Applied
Scientific EffectMagnetic coupling: Electromagnetic Induction

Data Source

PatentEP4184755B1Wireless power transmitter and wireless power transmission method by wireless power transmitter
Publication Date: 2025.10.22 LG ELECTRONICS INC
  • EP4184755B1 patent drawingFigure 1
  • EP4184755B1 patent drawingFigure 2
  • EP4184755B1 patent drawingFigure 3a

AI summary

A wireless power transmitter according to an embodiment of the present specification comprises: a power converter comprising a primary coil magnetically coupled to a secondary coil of a wireless power receiver to transmit wireless power; and a controller for communicating with the wireless power receiver and controlling the wireless power transmission, wherein the controller receives first information relating to the secondary coil from the wireless power receiver, receives second information relating to the position information of the wireless power receiver from the wireless power receiver, and distinguishes a state in which a foreign material is present between the wireless power receiver and the wireless power transmitter, and a misalignment state of the primary coil and secondary coil, on the basis of the first information and second information.