Induction Hob EMI Filter with Closed Magnetic Core

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing induction hobs face challenges in effectively reducing high-frequency noise generated in the power unit, which affects the AC mains voltage, requiring separate components for common mode and differential mode filtering, increasing complexity and costs.

Innovation Solution

An electromagnetic filtering section with a closed magnetic core element and coils provides both common mode and differential mode filtering capabilities in a single component, utilizing a bar-shaped or plate-shaped core element to enable direct magnetic flux and adjustable air gaps for tuned filtering behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate common mode and differential mode filtering components are used, then filtering effectiveness is improved, but device complexity and installation space increase

Engineering Contradiction:
Improvefiltering effectivenessVSAvoidfilter complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines separate common mode and differential mode filtering components into a single integrated electromagnetic interference filter. The filter housing contains both filtering circuits, allowing them to work simultaneously in one compact unit rather than requiring separate installations, thereby reducing device complexity while maintaining comprehensive filtering effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated EMI filter performs multiple filtering functions (both common mode and differential mode noise suppression) within a single device. This multi-functional design eliminates the need for separate filtering components, reducing overall system complexity and installation space while providing comprehensive electromagnetic interference protection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If separate common mode and differential mode filtering components are used, then filtering effectiveness is improved, but manufacturing costs increase

Engineering Contradiction:
Improvefiltering effectivenessVSAvoidmanufacturing costs
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By merging separate filtering components into one integrated unit, the patent reduces the total number of parts that need to be manufactured, stocked, and assembled. This consolidation simplifies the supply chain and manufacturing process, leading to lower production costs while maintaining effective noise filtering performance.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If multiple filtering components are used, then comprehensive noise suppression is achieved, but installation space increases

Engineering Contradiction:
Improvenoise suppression capabilityVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent integrates both common mode and differential mode filtering circuits into a single compact filter housing, dramatically reducing the installation space required compared to separate components. This consolidated design maintains comprehensive noise suppression capability while occupying minimal space in the power unit.

Inventive Principle:
Principle #5Merging (Combining)

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 solution reduces filter complexity and installation space while lowering manufacturing costs, achieving effective noise suppression with optimized common and differential mode filtering capabilities.

Implementation Method 1

said electromagnetic filtering section may particularly comprise a closed magnetic core element around which at least two coils are provided. Said closed magnetic core element and said coils preferably provide said common mode filtering means.

Methodology Applied
Scientific EffectMagnetic core: Magnetic Field

Implementation Method 2

Said differential mode filtering means more preferably are adapted to enable a direct magnetic flux between the coil ends of each coil in order to obtain differential mode filtering effect.

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 3

According to embodiments, an air gap is provided at one side or at each side between said bar-shaped or plate-shaped core element and said closed magnetic core element. Thereby, the filtering behaviour of the filtering section can be designed according the required needs.

Methodology Applied
Scientific EffectAir gap: Magnetic Reluctance

Data Source

PatentEP3478026B1Induction hob comprising an electromagnetic interference filter
Publication Date: 2021.06.30 ELECTROLUX APPLIANCES
  • EP3478026B1 patent drawingFigure 1~2
  • EP3478026B1 patent drawingFigure 3~4
  • EP3478026B1 patent drawingFigure 5~6

AI summary

Induction hob comprising an AC power input (2) and a power conversion entity (3) adapted to provide high frequency electric current to an induction coil, wherein an electromagnetic filtering section (1) is provided between said AC power input (2) and said power conversion entity (3), said electromagnetic filtering section (1) comprising common mode filtering means and differential mode filtering means, wherein said electromagnetic filtering section (1) comprises a closed magnetic core element (4) around which at least two coils (5, 6) are provided, said closed magnetic core element (4) and said coils (5, 6) providing said common mode filtering means, and wherein said differential mode filtering means are adapted to enable a direct magnetic flux between the coil ends (5.1, 5.2, 6.1, 6.2) of each coil (5, 6) in order to obtain differential mode filtering effect.