Induction Cooktop Inverter Control for Magnetic and Non-Magnetic Pans

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Solution Overview

Problem

Existing induction heating cooktops face challenges in efficiently heating both magnetic and non-magnetic cooking vessels due to varying output power based on vessel material, and they suffer from significant switching losses and heat generation issues with SiC elements.

Innovation Solution

The cooktop employs a SiC element as a switching element, uses different power control methods for each type of cooking vessel, and adjusts operating frequency and duty of switching elements based on vessel type to minimize losses and enhance heating efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single induction heating system is used for both magnetic and non-magnetic vessels, then the system structure is simple, but the heating output varies significantly depending on vessel material

Engineering Contradiction:
Improveheating output consistencyVSAvoidsystem structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system dynamically adjusts operating frequency based on vessel type detection. When a non-magnetic vessel is detected, the frequency is adjusted to a higher range (e.g., 20-100 kHz) to compensate for lower permeability and achieve consistent heating output across different vessel materials

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller changes key operating parameters (frequency and duty cycle) based on the detected vessel type. For non-magnetic vessels, both frequency and duty cycle are adjusted to optimize heating efficiency and maintain output consistency

Inventive Principle:
Principle #35Parameter changes

2Productivity

If high-frequency power is applied to heat non-magnetic vessels, then heating capability is improved, but switching losses increase

Engineering Contradiction:
Improveheating capabilityVSAvoidswitching losses
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The system uses dynamic frequency adjustment combined with duty cycle control to optimize the balance between heating capability and switching losses. The controller adapts operating parameters in real-time based on vessel type and heating requirements

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The inverter uses periodic switching of the SiC elements to generate high-frequency power. By controlling the switching duty cycle and frequency, the system achieves effective heating while managing switching losses through optimized periodic operation

Inventive Principle:
Principle #19Periodic action

3Speed

If SiC elements are used as switching elements, then switching speed is improved, but heat generation in switching elements increases

Engineering Contradiction:
Improveswitching speedVSAvoidheat generation
Core Design Contradiction:
SpeedVSTemperature

Solution Approach 1:

The system replaces traditional IGBT switching elements with SiC (silicon carbide) elements, which offer superior switching speed and lower on-resistance. This substitution enables faster switching and reduced conduction losses, despite the inherent heat generation challenges of high-power semiconductor devices

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

A heat dissipation fan is introduced as an intermediary cooling mechanism to manage the heat generated by SiC switching elements. The fan provides active thermal management, allowing the system to operate at high switching frequencies while maintaining safe operating temperatures

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach improves heating efficiency for both magnetic and non-magnetic vessels, reduces switching losses, and minimizes heat generation, leading to enhanced user convenience and reduced component deterioration, allowing for miniaturized and cost-effective heat dissipation systems.

Implementation Method 1

when high-frequency power having a predetermined intensity is applied to a coil, eddy current is generated in the object to be heated using magnetic fields generated around the coil so that the object to be heated is heated

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an inverter including a plurality of switching elements driven to allow current to flow through the working coil

Methodology Applied
Scientific EffectElectrical conductivity switching: Conduction (electrical)

Data Source

PatentEP4250875B1Induction heating-type cooktop
Publication Date: 2026.01.28 LG ELECTRONICS INC
  • EP4250875B1 patent drawingFigure 1~2
  • EP4250875B1 patent drawingFigure 3~4
  • EP4250875B1 patent drawingFigure 5

AI summary

The present disclosure provides a cooktop capable of heating both a magnetic receptacle and a non-magnetic receptacle by a high power output, and capable of switching a driving method of an inverter according to the type of cooking receptacle.