Working Coil Control for Wireless Power Misalignment Detection

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Solution Overview

Problem

Existing wireless power transmission systems for small home appliances face challenges in efficiently transferring power due to eccentricity between coils and the presence of foreign objects, which affects alignment, safety, and convenience, often requiring additional sensors and circuits that increase costs and complexity.

Innovation Solution

A wireless power transmission apparatus that compensates for eccentricity and detects foreign objects by analyzing load voltage variations, using a controller to determine the presence of foreign objects and provide alarms, without the need for separate sensors, ensuring reliable and stable operation across varying input voltages and eccentricity degrees.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional sensors and circuits are added to detect foreign objects and compensate for eccentricity, then detection reliability is improved, but device complexity increases

Engineering Contradiction:
Improveforeign object detection reliabilityVSAvoidsensor and circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The working coil serves multiple functions: it acts as both the heating coil for induction heating and the detection coil for foreign object detection. The controller performs multiple tasks including power supply control, foreign object detection through load voltage analysis, and eccentricity compensation, eliminating the need for separate sensors and detection circuits.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own working coil and controller to perform self-diagnosis and self-adjustment. The controller analyzes load voltage variations caused by foreign objects and automatically compensates for eccentricity by adjusting power supply parameters, without requiring external detection devices.

Inventive Principle:
Principle #25Self-service

2Productivity

If coil alignment is strictly required for efficient power transfer, then power transmission efficiency is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoiduser alignment convenience
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The controller continuously monitors load voltage variations that occur when foreign objects or eccentricity affect the magnetic field. Based on this feedback, the system automatically adjusts power supply parameters to compensate for misalignment, maintaining efficient power transfer without requiring precise manual alignment by the user.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts power supply parameters in response to detected eccentricity or foreign objects. The controller modifies operating conditions in real-time to optimize power transfer efficiency under varying alignment conditions, making the system adaptable rather than requiring fixed precise alignment.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If load voltage analysis is used for foreign object detection, then device complexity is reduced, but measurement precision may be affected by voltage fluctuations

Engineering Contradiction:
Improvedetection system complexityVSAvoidforeign object detection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The controller continuously monitors load voltage and compares it against expected values. When voltage deviations exceed thresholds that cannot be explained by normal operation or compensatable eccentricity, the system identifies foreign objects. This feedback mechanism allows accurate detection despite voltage fluctuations by recognizing abnormal patterns.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical or electromagnetic detection systems with an electrical measurement approach. By analyzing load voltage variations through the existing controller, the system achieves foreign object detection without additional sensors, using electrical signal analysis instead of physical detection mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The solution enables reliable detection and compensation for foreign objects and eccentricity, ensuring safe and efficient wireless power transfer by integrating these functions into a single apparatus, enhancing user convenience and reducing costs by eliminating the need for additional sensors.

Implementation Method 1

when alternating current (AC) flows in a transmission coil, a battery is charged by forming a magnetic field around a transmission coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a general electron induction heating device allows high-frequency current to flow in a working coil or heating coil installed therein. When the high-frequency current flows in the working coil or the heating coil, a strong line of magnetic force is generated. The line of magnetic force generated in the working coil or the heating coil forms eddy current while being transmitted through a cooking tool. Thus, as eddy current flows in a cooking tool, heat is generated

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a controller that receives a load voltage from the target object during wireless power transfer, compensates for the load voltage, and determines whether a foreign object is present in the working coil when the user selects a wireless power transmission mode

Methodology Applied
Scientific EffectVoltage analysis:

Data Source

PatentEP3872959A1Wireless power transmission apparatus for induction heating and control method thereof
Publication Date: 2021.09.01 LG ELECTRONICS INC
  • EP3872959A1 patent drawingFigure 1
  • EP3872959A1 patent drawingFigure 2~3
  • EP3872959A1 patent drawingFigure 4

AI summary

A wireless power transmission apparatus for induction heating includes a working coil configured to change a mode depending on selection of a user, to change an operation frequency depending on the mode, and to induction-heat a target object, or to wirelessly transmit power to the target object, an inverter that is turned on and off depending on the operation frequency and configured to generate the power, and a controller configured to receive a load voltage from the target object during wireless power transfer, to compensate for the load voltage, and to determine whether a foreign object is present in the working coil when the user selects a wireless power transmission mode.