Induction heating cooker

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Solution Overview

Problem

Existing induction cookers face limitations in non-contact power transfer due to attenuation of electric power caused by induced currents in conductive frames surrounding non-magnetic top plates, restricting the placement position of power receiving devices and affecting efficiency.

Innovation Solution

An induction cooker design featuring a top plate with a conductive frame having discontinuous portions, allowing magnetic-resonance non-contact power transfer with a power transfer coil and power receiving coil, which reduces induced currents and enhances placement flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a continuous conductive frame surrounds the top plate, then structural strength and electrical shielding are improved, but induced currents are generated causing power attenuation

Engineering Contradiction:

Improvepower attenuationVSAvoidframe structural strength

Core Design Contradiction:

Loss of energyVSStrength

Solution Approach 1:

The continuous conductive frame is segmented into multiple separate conductive members by introducing discontinuous portions. This segmentation prevents the formation of closed loops, thereby eliminating induced currents while maintaining structural integrity through alternative design arrangements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The harmful continuous conductive path is extracted from the frame structure by removing specific portions. This eliminates the closed circuit that causes induced currents and power attenuation, while the frame still provides structural support through its discontinuous configuration.

Inventive Principle:

Principle #2Taking out (Extraction)

2Loss of energy

If electromagnetic induction coupling is used for power transfer, then power transfer efficiency is improved, but placement position of power receiving device is restricted

Engineering Contradiction:

Improvepower transfer efficiencyVSAvoidplacement position flexibility

Core Design Contradiction:

Loss of energyVSAdaptability or versatility

Solution Approach 1:

The system utilizes magnetic resonance (a form of oscillating magnetic field) instead of static electromagnetic induction. By operating at resonant frequencies, the power transfer achieves high efficiency similar to induction coupling while allowing greater spatial flexibility in device placement.

Inventive Principle:

Principle #18Mechanical vibration

Solution Approach 2:

The power transfer mechanism transitions from low-frequency electromagnetic induction to high-frequency magnetic resonance. This parameter change in operating frequency enables both high efficiency and improved placement flexibility by allowing wireless power transfer over larger distances and with less stringent alignment requirements.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If magnetic resonance is used for power transfer, then placement position flexibility is improved, but induced currents in frame cause power attenuation

Engineering Contradiction:

Improveplacement position flexibilityVSAvoidpower attenuation

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The frame is segmented into discontinuous conductive members that cannot form closed loops. This eliminates the path for induced currents while preserving the magnetic resonance power transfer capability and its associated placement flexibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The continuous conductive path that causes harmful induced currents is extracted from the frame structure. The discontinuous frame members provide structural support without creating closed circuits, thus eliminating power attenuation while maintaining placement flexibility.

Inventive Principle:

Principle #2Taking out (Extraction)

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 design effectively suppresses power attenuation and improves the usability of induction cookers by allowing flexible placement of power receiving devices without facing the power transfer coil, maintaining high transfer efficiency even at increased distances.

Implementation Method 1

a power transfer coil configured to transfer electric power by magnetic resonance

Methodology Applied

Scientific EffectMagnetic resonance: Resonance

Implementation Method 2

a heating coil disposed below the top plate, and configured to inductively heat the heating target

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3697175B1Induction heating cooker

Publication Date: 2021.07.28 MITSUBISHI ELECTRIC CORP

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AI summary

An induction cooker according to the present disclosure includes a body including a top plate on which a heating target is placed, a frame formed to surround an outer periphery of the top plate, and having a discontinuous portion being electrically discontinuous from other parts of the frame, a heating coil disposed below the top plate, and configured to inductively heat the heating target, a driver circuit configured to supply electric power to the heating coil, a power transfer coil configured to transfer electric power by magnetic resonance, and a power transfer circuit configured to supply electric power to the power transfer coil, and a power receiving device including a power receiving coil configured to receive electric power from the power transfer coil by magnetic resonance, and a load circuit configured to operate by the electric power received by the power receiving coil.