Induction coil for heating cookware, induction hob and cooking hob system

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Solution Overview

Problem

Existing induction coils for heating cookware heat unevenly due to non-uniform power distribution, leading to reduced energy efficiency and difficulty in achieving even frying, especially on non-circular hotplates.

Innovation Solution

The induction coil design features a winding group with varying spacing between coil windings, including a reduced spacing in intermediate sections, and a change in winding density to ensure uniform heating, with ferrites arranged to enhance magnetic flux density distribution and prevent hotspots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the induction coil has a rectangular outer contour with uniform winding density, then the device complexity is reduced and manufacturing is simplified, but the heating uniformity deteriorates and energy efficiency is reduced

Engineering Contradiction:
Improvecoil manufacturing simplicityVSAvoidheating uniformity
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent applies local quality by varying the winding density in different regions of the induction coil. Specifically, the intermediate sections have reduced winding density compared to the corner areas, creating locally optimized heating characteristics that compensate for the non-circular geometry and achieve uniform heat distribution across the hotplate surface.

Inventive Principle:
Principle #3Local quality

2Device complexity

If the winding spacing is uniform across the induction coil, then the device complexity is reduced, but the power distribution uniformity deteriorates leading to hotspots and uneven heating

Engineering Contradiction:
Improvewinding spacing complexityVSAvoidpower distribution uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by systematically varying the winding spacing parameter across different sections of the coil. The intermediate sections feature increased spacing between windings, while corner areas maintain tighter spacing, thereby modulating the magnetic field density and achieving uniform power distribution without requiring complex control systems.

Inventive Principle:
Principle #35Parameter changes

3Power

If the induction coil uses high winding density throughout, then the power output is increased, but the heating uniformity deteriorates with excessive power concentration in certain areas

Engineering Contradiction:
Improvetotal power outputVSAvoidheat distribution evenness
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent distributes power output uniformly by applying local quality principles to the winding density. Intermediate sections have lower winding density to reduce power concentration, while corner areas have higher density to maintain adequate power output. This localized optimization ensures that the total power is distributed evenly across the entire hotplate surface.

Inventive Principle:
Principle #3Local quality

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 design achieves uniform heating across non-circular hotplates, improving energy efficiency and cooking results by ensuring even heat distribution and reducing power density variations.

Implementation Method 1

A winding group with at least two coil windings, preferably running around a coil axis, for generating a magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The winding spacing can have at least one spacing maximum within the intermediate section. According to one aspect of the invention, the winding spacing within the intermediate section can be reduced along the circumferential direction on both sides of the spacing maximum

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Data Source

PatentEP4221462A1Induction coil for heating cookware, induction hob and cooking hob system
Publication Date: 2023.08.02 BORA VERTRIEBS GMBH & CO KG
  • EP4221462A1 patent drawingFigure 1
  • EP4221462A1 patent drawingFigure 2
  • EP4221462A1 patent drawingFigure 3

AI summary

An induction coil (16) for heating cooking utensils comprises a winding group (32) with at least two coil turns (28) extending around a coil axis (30) for generating a magnetic field, wherein the winding group (32) has at least one intermediate section (38) extending along a circumferential direction (ϕ) around the coil axis (30) between two successive maxima (rmax) of the radial extent (r) of an outer contour of the winding group (32), wherein a variable winding spacing (d) exists along the circumferential direction (ϕ) between at least two of the coil turns (28) of the winding group (32), wherein the winding spacing (d) within the intermediate section (38) has at least one spacing maximum (dmax), and wherein the winding spacing (d) within the intermediate section (38) decreases on both sides of the spacing maximum (dmax) along the circumferential direction (ϕ).