Wireless power transmission apparatus for induction heating and control method thereof

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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, particularly in induction heating and wireless charging applications.

Innovation Solution

A wireless power transmission apparatus that determines eccentricity and foreign object presence using a controller to adjust operation frequency and provide user alarms, allowing for efficient power transfer without physical repositioning of objects, and integrates a user input unit for mode selection, enabling both induction heating and wireless charging using a single working coil.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If wireless power transmission is performed with eccentric coil alignment, then power transmission can be attempted, but power transmission efficiency is remarkably lowered

Engineering Contradiction:
Improveease of operationVSAvoidpower transmission efficiency
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The system measures the coupling factor between transmission and reception coils to detect alignment status, then provides real-time feedback to the user through a display unit indicating the degree of misalignment. This feedback mechanism guides users to achieve proper coil alignment, thereby maximizing power transmission efficiency while maintaining ease of operation.

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If a multi-functional device is designed to perform both induction heating and wireless charging, then versatility is improved, but device complexity increases

Engineering Contradiction:
ImproveversatilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a single working coil that can operate in multiple modes: induction heating mode for direct heating applications and wireless charging mode for battery charging. The controller switches between these modes based on the presence and type of object detected, allowing one device to perform multiple functions without requiring separate coils or complex additional components.

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

Solution Approach 2:

The system changes operational parameters such as frequency and power level based on the detected mode. For induction heating, higher frequencies and power levels are used to generate eddy currents in cookware. For wireless charging, different frequency and coupling conditions are applied. This parameter adaptation allows a single coil structure to serve multiple functions efficiently.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If foreign object detection is implemented during wireless power transmission, then safety is improved, but measurement precision requirements increase

Engineering Contradiction:
ImprovesafetyVSAvoidmeasurement precision
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The coupling factor serves as an intermediary measurement parameter that indirectly indicates both alignment status and the presence of foreign objects. By measuring the coupling factor between transmission and reception coils, the system can detect anomalies that suggest foreign object presence without requiring direct sensing of the foreign object itself, thus improving safety while avoiding complex direct detection mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 power transmission efficiency by compensating for eccentricity and detecting foreign objects, ensuring safe and convenient operation by adjusting frequencies and providing user alerts, thereby improving alignment and reducing the risk of ignition or degradation in power transfer.

Implementation Method 1

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 to heat a container itself

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

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 EffectEddy current: Eddy Currents

Implementation Method 3

when alternating current (AC) flows in a transmission coil, a battery is charged by forming a magnetic field around a transmission coil, allowing AC to flow in a reception coil due to influence of the magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3872961A1Wireless power transmission apparatus for induction heating and control method thereof
Publication Date: 2021.09.01 LG ELECTRONICS INC
  • EP3872961A1 patent drawingFigure 1
  • EP3872961A1 patent drawingFigure 2~3
  • EP3872961A1 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 configure to calculate an eccentricity degree between the working coil and a reception coil of the target object and to control the operation frequency depending on the calculated eccentricity degree while performing wireless power transfer when the user selects a wireless power transfer mode.