Induction Coil Assembly with Ferrite Layer for Inverter Efficiency

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Solution Overview

Problem

Existing induction coils in cooktops face inefficiencies and require improvements in electrical efficiency and resistance, particularly when operating with full-bridge inverters.

Innovation Solution

The induction coil assembly incorporates a resonant circuit with a capacitor range of 0.1 to 0.6 microfarads and a coil operating at 50 to 150 kHz, utilizing a full-bridge inverter and a unique arrangement of a ferrite layer to enhance resistance and optimize induction heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If existing induction coils are used in cooktops, then the basic induction heating function is provided, but electrical efficiency is insufficient and resistance is inadequate when operating with full-bridge inverters

Engineering Contradiction:
Improveelectrical efficiencyVSAvoidperformance with full-bridge inverter
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies parameter changes by optimizing the coil's electrical characteristics including resistance (0.05-0.2 ohms), inductance (40-80 microhenries), and operating frequency (50-150 kHz). These parameter adjustments enable the coil to achieve enhanced electrical efficiency and improved performance when operating with full-bridge inverters, directly resolving the technical contradiction between energy efficiency and reliability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the coil size and structure are increased to improve resistance and efficiency, then electrical performance improves, but the cooktop design becomes less slim and more complex

Engineering Contradiction:
ImproveresistanceVSAvoidcoil assembly structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs composite materials by integrating the induction coil with ferrite layers and protective coatings to enhance resistance and electrical performance without increasing the overall size. This composite structure allows the coil assembly to achieve improved reliability while maintaining a compact, slim design, effectively resolving the contradiction between resistance improvement and device complexity.

Inventive Principle:
Principle #40Composite materials

3Use of energy by moving object

If the coil operating frequency is increased to improve efficiency, then electrical efficiency improves, but the resonant circuit components become more complex and costly

Engineering Contradiction:
Improveelectrical efficiencyVSAvoidresonant circuit
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent optimizes the operating frequency parameter within the range of 50-150 kHz to achieve enhanced electrical efficiency. By carefully selecting and tuning this frequency parameter in conjunction with the resonant circuit components (capacitor: 0.1-0.6 microfarads), the system achieves improved energy efficiency while keeping the resonant circuit design practical and cost-effective, resolving the contradiction between efficiency improvement and circuit complexity.

Inventive Principle:
Principle #35Parameter changes

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 solution provides enhanced electrical efficiency, increased resistance, and a slim design, while maintaining cost-effectiveness by using a full-bridge inverter and a ferrite layer to focus magnetic fields effectively.

Implementation Method 1

a coil disposed under the cooking surface and configured to operate at a working frequency of between 50 kHz and 150 kHz

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a unique arrangement of a ferrite layer to enhance resistance and optimize induction heating

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 3

a resonant circuit having a resonant frequency in the range of 40 kHz to 60 kHz

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4601410A1Induction coil assembly
Publication Date: 2025.08.13 WHIRLPOOL CORP
  • EP4601410A1 patent drawingFigure 1
  • EP4601410A1 patent drawingFigure 2
  • EP4601410A1 patent drawingFigure 3

AI summary

An induction cooktop (10) includes a cooking surface (12) operable to support cookware (14) and a resonant circuit (16) having a resonant frequency in the range of 40 kHz to 60 kHz. The resonant circuit (16) includes a capacitor (18) having capacitance of between 0.1 micro-Farads and 0.6 micro-Farads and a coil (20) disposed under the cooking surface (12) and configured to operate at a working frequency of between 50 kHz and 150 kHz. The induction cooktop (10) includes an induction control circuit configured to power the resonant circuit (16) at the working frequency.