Induction Heating Coil Switching for Flexible Output Control

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Solution Overview

Problem

Existing induction heating apparatuses face inefficiencies due to the inability to adjust the outputs of multiple working coils independently and the difficulty in using all coils based on the size and type of the object being heated, leading to suboptimal current supply and heating performance.

Innovation Solution

The induction heating apparatus includes a working coil base accommodating two coils, with adjustable connections via relays controlled by a controller, allowing for parallel or series configurations based on the object's type and desired output, enhancing coil utilization and current conversion efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple working coils are connected in parallel to increase heating capacity, then the heating power is improved, but the output adjustment flexibility and current supply efficiency deteriorate

Engineering Contradiction:
Improveheating powerVSAvoidoutput adjustment flexibility
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The patent divides the working coils into multiple independent groups, each with its own switching mechanism. This segmentation allows individual coils to be activated or deactivated based on heating requirements, enabling flexible output adjustment while maintaining the ability to scale heating power by activating more coil groups.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic control of coil connections through switching circuits that can reconfigure the electrical connections between coils. This dynamic reconfiguration capability allows the system to adapt the number of active coils and their connection arrangements (series/parallel) based on real-time heating needs, improving both power flexibility and efficiency.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If multiple working coils of different sizes are used to match object sizes, then the adaptability to different objects is improved, but the complexity of coil selection and connection increases

Engineering Contradiction:
Improveadaptability to different objectsVSAvoidcoil selection and connection complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs a universal coil configuration system where the same set of working coils can serve multiple heating scenarios through different connection arrangements. The switching circuits enable the coils to be connected in series, parallel, or mixed configurations, allowing a single coil set to handle both small and large objects without requiring separate dedicated coil assemblies.

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

Solution Approach 2:

The patent changes the electrical connection parameters (series/parallel configuration, switching states) of the working coils to adapt to different heating requirements. By dynamically adjusting connection parameters rather than physically reconfiguring coil arrangements, the system achieves adaptability to different object sizes while maintaining simple hardware architecture.

Inventive Principle:
Principle #35Parameter changes

3Power

If all working coils are always connected to maximize heating capacity, then the heating power is improved, but the current supply efficiency and energy waste increase

Engineering Contradiction:
Improveheating capacityVSAvoidcurrent supply efficiency
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent applies partial action by activating only the necessary number of working coils required for the specific heating task rather than always operating all coils. The switching circuits enable selective activation of coil groups based on the heating load, preventing excessive action that would waste energy while ensuring sufficient heating capacity when needed.

Inventive Principle:
Principle #16Partial or excessive action

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 configuration enables all coils to be utilized regardless of object size, adjusts output according to object type, and improves current conversion efficiency by optimizing coil connections for precise heat control.

Implementation Method 1

induction heating involves generating eddy current in an object to be heated made of metal (e.g., a cooking container) with a magnetic field that is generated around a coil when high-frequency power having predetermined magnitude is supplied to the coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

induction heating involves generating eddy current in an object to be heated made of metal

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Implementation Method 3

a resonance capacitor that connects to the other end of the second working coil

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4040917B1Induction heating apparatus and method for controlling the same
Publication Date: 2025.08.20 LG ELECTRONICS INC
  • EP4040917B1 patent drawingFigure 1~2
  • EP4040917B1 patent drawingFigure 3~6
  • EP4040917B1 patent drawingFigure 7~9

AI summary

The induction heating apparatus of one embodiment includes a current conversion circuit that converts current supplied from an external power source, a first working coil whose one end is connected to the current conversion circuit, a second working coil whose one end is connected to the current conversion circuit or the other end of the first working coil, a working coil base that accommodates the first working coil and the second working coil, a resonance capacitor that connects to the other end of the second working coil, a first relay that adjusts a connection between the other end of the first working coil and the resonance capacitor, a second relay that selectively connects one end of the second working coil to any one of the other end of the first working coil and the current conversion circuit, and a controller that controls the first relay's and the second relay's connections.