Induction Cooktop Pot Detection With Low-Power Sensing Coil

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Solution Overview

Problem

Conventional induction heating devices consume high power to determine if a pot is compatible with induction heating and lack the ability to simultaneously measure the object's temperature and type, requiring users to manually select heating regions.

Innovation Solution

An induction heating device equipped with a loaded-object sensor featuring a cylindrical hollow body with a sensing coil and a temperature sensor, allowing for inductive sensing and temperature measurement, which reduces power consumption and eliminates the need for manual heating-region selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a predetermined amount of power is supplied to the working coil for a predetermined time to determine whether eddy current occurs in the pot, then the suitability of the pot for induction heating can be determined, but relatively high levels of power (200 W or more) are consumed during the determination process

Engineering Contradiction:
Improvedetermination accuracy of pot compatibilityVSAvoidpower consumption during pot compatibility determination
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent divides the pot compatibility determination process into two distinct stages: a preliminary determination stage using a sensor coil that consumes low power, and a confirmation stage using the working coil that consumes high power. This segmentation allows the system to filter out obviously incompatible pots first, thereby reducing the frequency and duration of high-power operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a preliminary determination step before the main heating operation. The sensor coil performs an initial assessment of pot compatibility using minimal power consumption. Only pots that pass this preliminary check proceed to the confirmation stage, preventing wasteful consumption of high power on incompatible pots.

Inventive Principle:
Principle #10Preliminary action

2Loss of energy

If the induction heating device heats only the pot itself by inductive heating, then energy efficiency is improved and the loading plate remains relatively cool, but the device cannot simultaneously measure the object's temperature and determine its type

Engineering Contradiction:
Improveenergy efficiency of heating processVSAvoidsimultaneous temperature measurement and object type determination capability
Core Design Contradiction:
Loss of energyVSMeasurement precision

Solution Approach 1:

The patent introduces a sensor coil as an intermediary component between the loading plate and the working coil. This sensor coil serves dual purposes: it acts as a detection element for pot compatibility determination and functions as a measurement probe for temperature sensing. This intermediary enables the system to perform measurement functions without requiring the working coil to be directly involved, thus maintaining energy efficiency while adding measurement capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The sensor coil is designed to perform multiple functions: it determines pot compatibility through eddy current detection, measures the temperature of the pot, and provides feedback for control purposes. This multi-functionality eliminates the need for separate measurement devices, maintaining the energy efficiency of the induction heating system while enabling simultaneous temperature measurement and object type determination.

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

3Device complexity

If conventional induction heating devices require manual selection of heating regions by users, then device complexity is reduced, but ease of operation deteriorates

Engineering Contradiction:
Improvestructural simplicity of heating deviceVSAvoiduser convenience in heating region selection
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent implements an automatic detection and identification system that enables the heating device to autonomously determine the presence, type, and optimal heating region for the placed pot. The sensor coil detects the pot's characteristics, and the control unit automatically selects the appropriate heating parameters and region. This self-service capability eliminates the need for manual intervention, significantly improving ease of operation while adding intelligent detection and control functions to the device.

Inventive Principle:
Principle #25Self-service

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 device accurately and quickly determines the type and temperature of the loaded object while consuming less power, enabling intuitive operation and efficient heating.

Implementation Method 1

a sensing coil wound on an outer face of the body

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a temperature sensor accommodated in a receiving space formed inside the body of the sensor

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

applying a high-frequency voltage (e.g., an alternating current) of a predetermined magnitude to the working coil. Accordingly, an inductive magnetic field may be generated around the working coil. When a pot containing certain metals or other inductive metals is positioned on or near the working coil to receive the flux of the generated inductive magnetic field, an eddy current may be generated inside the bottom of the pot

Methodology Applied
Scientific EffectMagnetic induction: Electromagnetic Induction

Implementation Method 4

magnetic induction from the magnetic field may cause an eddy current to be generated in an adjacent pot made of a certain metals so that the pot itself may be heated due to electrical resistance from the eddy current

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 5

the pot itself may be heated due to electrical resistance from the eddy current

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3422810B1Induction heating device and method for controlling the same
Publication Date: 2021.07.28 LG ELECTRONICS INC
  • EP3422810B1 patent drawingFigure 1
  • EP3422810B1 patent drawingFigure 2
  • EP3422810B1 patent drawingFigure 3

AI summary

The present disclosure relates to an induction heating device and a method for controlling the same. In accordance with the present disclosure, first, inductive sensing is periodically performed to detect a specific object with inductive heating property. Next, current sensing of the specific object having the inductive heating property is performed to again check whether the specific object has the inductive heating property. Thus, when the user simply places the loaded object on the device, the device may allow the user to quickly and intuitively confirm whether the corresponding loaded object has the inductive heating property.