Rectangular Coil Assembly for Induction Heating Efficiency

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Solution Overview

Problem

Conventional induction heating devices with a free zone scheme experience reduced power efficiency and increased heating time due to non-coil regions between the working coils and the casing walls, which are not optimized for the placement of cooking vessels.

Innovation Solution

A coil assembly with a rectangular shape and working coils extending alternately between opposite directions, eliminating non-coil regions between the working coils and the casing walls, ensuring consistent heating power regardless of vessel placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a free zone scheme is used with circular working coils, then the heating region can accommodate various vessel shapes, but non-coil regions are created between the coils and casing walls causing reduced power efficiency

Engineering Contradiction:
Improvevessel placement flexibilityVSAvoidpower efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent transitions from circular working coils to rectangular working coils that match the rectangular heating region and casing geometry. This asymmetric shape change eliminates the non-coil regions between circular coils and rectangular casing walls, ensuring the coil assembly extends fully to the casing boundaries while maintaining versatility for various vessel placements on the heating surface.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent optimizes the spatial arrangement by configuring the rectangular working coils to extend in alternating directions (first direction and second direction perpendicular to each other) within the rectangular coil assembly. This dimensional optimization ensures complete coverage of the heating region without gaps, eliminating energy loss areas while preserving the free zone scheme's adaptability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If non-coil regions exist between working coils and casing walls, then the coil structure is simpler, but heating time increases due to reduced heating power

Engineering Contradiction:
Improvecoil structure simplicityVSAvoidheating time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The rectangular coil configuration replaces circular coils, maintaining structural simplicity while optimizing the geometry to match the rectangular heating region. This eliminates non-coil regions that would otherwise reduce heating power, thereby preventing increased heating time without adding structural complexity.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent transitions from curved circular coil geometry to straight-edged rectangular coil geometry. This shape change eliminates the inherent gaps between circular coils and rectangular casing boundaries, maximizing the active heating area and maintaining high heating power output with a simple rectangular structure.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Ease of manufacture

If circular working coils are used in a rectangular heating region, then manufacturing is easier, but non-coil regions create uneven heating distribution

Engineering Contradiction:
Improvecoil manufacturing easeVSAvoidheating uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent adopts rectangular working coils that match the rectangular heating region geometry. This shape correspondence ensures uniform magnetic field distribution across the entire heating area without the non-coil regions that cause uneven heating, while the rectangular configuration remains equally manufacturable using standard coil winding techniques.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The rectangular coil configuration creates a homogeneous magnetic field distribution across the rectangular heating region by eliminating non-coil regions. This ensures uniform heating performance throughout the heating area, matching the geometric homogeneity of the rectangular structure with the magnetic field distribution.

Inventive Principle:
Principle #33Homogeneity

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 maintains constant heating power and prevents increased heating and cooking times by optimizing the coil arrangement within the induction heating device.

Implementation Method 1

when high-frequency power of a predetermined magnitude is applied to the working coil, an eddy current is generated in the cooking vessel made of a metal using a magnetic field generated around the working coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an eddy current is generated inside the bottom of the cooking vessel. When the resulting eddy current flows in the bottom of the cooking vessel, the cooking vessel itself is heated

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Implementation Method 3

heat generated when current flows through a metal resistance wire or a non-metallic heating element, such as silicon carbide, is transmitted to the cooking vessel through radiation or conduction

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3422814B1Coil assembly and inductively-heating device including the coil assembly
Publication Date: 2024.10.16 LG ELECTRONICS INC
  • EP3422814B1 patent drawingFigure 1
  • EP3422814B1 patent drawingFigure 2
  • EP3422814B1 patent drawingFigure 3~4

AI summary

A coil assembly and an induction heating device including a coil assembly are provided. The coil assembly may include a coil frame having a shape corresponding to a shape of a heating region defined in a plate. A working coil may extend alternately in between opposite first and second directions, rather than being circularly arranged as in related art coil assemblies.