Multi-Coil Induction Heating Load Detection via Sequential Segmentation

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Solution Overview

Problem

Multi-coil induction heating devices face challenges in implementing energy-saving and accurate load detection in a short time, as existing methods are inefficient in quickly identifying the position of a load on multiple heating coils.

Innovation Solution

The induction heating device employs a controller that supplies a detection current to all heating coils, determines the presence of a load, and then sequentially checks each coil, connecting all coils to the driver after load detection is confirmed, utilizing a switching unit and electric signal detectors to optimize load detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a detection current is supplied to all heating coils simultaneously, then load detection can be performed quickly, but energy consumption increases

Engineering Contradiction:
Improveload detection timeVSAvoidenergy consumption during detection
Core Design Contradiction:
Loss of timeVSUse of energy by moving object

Solution Approach 1:

The patent divides the heating coils into multiple groups and performs load detection in a sequential manner across different time periods. In the first time period, detection current is supplied to only one group of coils at a time rather than all coils simultaneously. This segmentation approach reduces the total energy consumption during detection while still achieving complete load detection across all coils within an acceptable time frame.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If detection current is supplied to all heating coils, then accurate load position detection is achieved, but it prevents energy saving

Engineering Contradiction:
Improveload position detection accuracyVSAvoidenergy wastage during detection
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent segments the detection process into multiple stages: first performing detection on one group of coils at a time, then based on the detection results, determining which specific heating coils require activation. This segmented approach maintains accurate load position detection by systematically checking all coils while avoiding unnecessary energy consumption on coils that don't require heating.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by supplying detection current to only one group of heating coils at a time rather than all coils simultaneously. The detection process is performed in parts across different time periods, which reduces energy wastage while still achieving complete and accurate load position detection through the cumulative results of multiple detection cycles.

Inventive Principle:
Principle #16Partial or excessive action

3Loss of energy

If sequential detection of each heating coil is performed, then energy consumption is reduced, but detection time increases

Engineering Contradiction:
Improveenergy consumption during detectionVSAvoidtotal detection time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The patent performs preliminary load detection in the first time period by sequentially checking groups of heating coils before actual heating operation begins. This preliminary detection identifies which coils need to be activated, allowing the system to prepare the appropriate heating configuration in advance. The second time period then focuses detection only on the identified coils, reducing total detection time while maintaining energy efficiency.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If all heating coils are connected to driver after detection, then heating operation is ready, but energy is wasted on coils not needing heating

Engineering Contradiction:
Improveheating operation readinessVSAvoidenergy waste on unnecessary coils
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent implements feedback control by using the load detection results to determine which specific heating coils should be connected to the driver and activated. The controller receives detection signals from each coil group and uses this feedback information to selectively connect only the necessary coils to the driver for heating operation, avoiding energy waste on coils that are not required for the current heating task.

Inventive Principle:
Principle #23Feedback

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

This approach enables quick and accurate load detection, reducing energy wastage and improving the efficiency of heating coil operation by ensuring only the necessary coils are activated, thus enhancing the overall performance of multi-coil induction heating devices.

Implementation Method 1

an induction heating device that inductively heats a load, such as a metal cooking pot, placed on a top panel

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a multi-coil induction heating device having multiple heating coils provided below the top panel

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 3

detects a change in an electric signal on a conduction path which connects a power source of the heating cooker to each of the heating coils

Methodology Applied
Scientific EffectElectrical signal detection:

Data Source

PatentEP3509398B1Induction heating device and load detection method in induction heating device
Publication Date: 2020.01.22 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3509398B1 patent drawingFigure 1~2
  • EP3509398B1 patent drawingFigure 3~4
  • EP3509398B1 patent drawingFigure 5

AI summary

In a multi-coil induction heating device, a detection current is supplied to all of a plurality of heating coils (3) by driver (4) and switching unit (8). Controller (50) determines whether a load is placed above the plurality of heating coils (3) based on an electric signal in response to the detection current. When determining that the load is placed above the plurality of heating coils (3), controller (50) determines whether the load is placed above each of the plurality of heating coils (3) by sequentially and independently supplying the detection current to each of the plurality of heating coils (3). After the determination for each of the plurality of heating coils (3) is performed, switching unit (8) connects all heating coils (3) to driver (4). According to this aspect, energy-saving and accurate load detection is possible in a short time in the multi-coil induction heating device.