Induction Heating Coil Resonance Switching for WPT Mode Sharing

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Solution Overview

Problem

Induction heat cooking apparatuses face limitations in efficiently switching between cooking device heating and wireless power transfer modes, with existing systems often requiring separate coils and frequency adjustments, which can lead to inefficiencies and compatibility issues with variable loads.

Innovation Solution

The induction heat cooking apparatus incorporates a WPT capacitor connected in parallel to the resonance capacitor, controlled by mode conversion switches, allowing the same heating coil to operate in both cooking device heating and wireless power transfer modes, with a PFC power converter ensuring stable output to variable loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate coils are used for heating and wireless power transfer, then the reliability of each function is improved, but the device complexity increases

Engineering Contradiction:
Improvefunctional reliabilityVSAvoidcoil structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a universal heating coil that can operate in both induction heating mode and wireless power transfer mode by changing the capacitance configuration. The same coil structure serves dual purposes, eliminating the need for separate coils while maintaining functional reliability through mode-specific capacitance tuning.

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

Solution Approach 2:

The patent merges the heating function and wireless power transfer function into a single integrated system using one coil. By combining these functions and using a mode conversion switch to adjust capacitance, the system achieves both heating and WPT capabilities without requiring separate hardware components.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If frequency adjustments are made for wireless power transfer mode, then the adaptability to different loads is improved, but the loss of time for mode switching increases

Engineering Contradiction:
Improveload compatibilityVSAvoidmode switching time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent changes the capacitance parameter of the resonant circuit to switch between heating mode and wireless power transfer mode. By using a mode conversion switch that reconfigures the capacitance connection (parallel or series), the system achieves frequency adjustment for different modes without complex frequency sweeping, reducing mode switching time while maintaining adaptability to different loads.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the same heating coil is used for both heating and wireless power transfer, then the device complexity is reduced, but the reliability of mode switching deteriorates

Engineering Contradiction:
Improvecoil configurationVSAvoidmode switching reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a mode conversion switch as an intermediary component that reliably controls the connection configuration of the capacitance. This switch acts as a mediator between the single coil and the two operating modes, ensuring reliable mode switching by providing clear on/off states for capacitance connection, thereby maintaining functional reliability while using a unified coil structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Adaptability or versatility

If capacitance is adjusted for wireless power transfer mode, then the adaptability to variable loads is improved, but the device complexity increases

Engineering Contradiction:
Improvevariable load compatibilityVSAvoidcapacitance configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a dynamic capacitance configuration system where the capacitance value can be changed based on the operating mode. The mode conversion switch dynamically reconfigures the capacitance connection (parallel for heating mode, series for WPT mode), allowing the system to adapt to variable loads in wireless power transfer mode while maintaining simple structure through a single switching mechanism.

Inventive Principle:
Principle #15Dynamics

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 solution enables efficient switching between heating and wireless power transfer modes, improving energy efficiency and compatibility with variable loads, while maintaining high power factor and efficiency across both operations.

Implementation Method 1

When the high frequency current flows through the working coil or the heating coil, lines of strong magnetic force are generated. The lines of the magnetic force generated in the working coil or the heating coil generate eddy current when passing through a cooking device. Thus, since the eddy current flows through the cooking device, heat is generated to heat a container itself.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The lines of the magnetic force generated in the working coil or the heating coil generate eddy current when passing through a cooking device. Thus, since the eddy current flows through the cooking device, heat is generated to heat a container itself.

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Implementation Method 3

since the eddy current flows through the cooking device, heat is generated to heat a container itself

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 4

a WPT capacitor, which is not connected to a resonance capacitor or is connected in parallel to the resonance capacitor as the induction heat cooking apparatus operates in a cooking device heating mode or a wireless power transfer mode

Methodology Applied
Scientific EffectMagnetic resonance: Resonance

Data Source

PatentEP3570637B1Induction heat cooking apparatus to implement WPT and PFC power converter
Publication Date: 2020.08.19 LG ELECTRONICS INC
  • EP3570637B1 patent drawingFigure 1~2
  • EP3570637B1 patent drawingFigure 3~4
  • EP3570637B1 patent drawingFigure 5a~5b

AI summary

Provided is an induction heat cooking apparatus. The induction heat cooking apparatus includes a rectifier configured to convert an AC voltage supplied from an external power source into a DC voltage, an inverter configured to receive the voltage from the rectifier to supply current to heating coils, the heating coils configured to generate magnetic fields when the current flows through the inverter, a resonance capacitor including both DC terminals through which the voltage is outputted from rectifier and a plurality of capacitors connected in series to each other between the heating coils, a wireless power transfer (WPT) capacitor connected in parallel to the resonance capacitor, and a mode conversion switch configured to determine whether to connect the resonance capacitor to the WPT capacitor in parallel.