Induction Hob Control Unit Reducing Acoustic Coupling Noise

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Solution Overview

Problem

Cooking appliances, particularly induction hobs, face challenges in minimizing acoustic coupling noises and ensuring even power distribution due to magnetic coupling between induction targets, leading to unfavorable acoustic loads and potential flicker issues.

Innovation Solution

A cooking appliance device with a control unit that detects coupling parameters between induction targets and adjusts their operation to reduce coupling noises by maintaining constant activation and average power, using separate energy sources for each target and coordinating their heating frequencies to avoid intermodulation noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If induction targets are operated simultaneously at different heating frequencies, then productivity is improved, but acoustic coupling noises are generated

Engineering Contradiction:
Improvesimultaneous operation of multiple induction targetsVSAvoidacoustic coupling noises
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies periodic action by alternating the operation of multiple induction targets in time intervals rather than operating them simultaneously. The control unit switches between different induction targets periodically, ensuring that only one target is active at any given moment, thereby preventing magnetic coupling noises while maintaining overall productivity through continuous cycling of multiple zones.

Inventive Principle:
Principle #19Periodic action

2Productivity

If induction targets are operated at different heating frequencies, then productivity is improved, but coupling noises occur

Engineering Contradiction:
Improveheating performanceVSAvoidcoupling noises
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The control unit implements periodic switching between different heating frequencies and different induction targets. By alternating operation in a periodic manner and ensuring that induction targets are not active simultaneously, the system achieves effective heating performance while avoiding the intermodulation and coupling noises that would result from simultaneous operation at different frequencies.

Inventive Principle:
Principle #19Periodic action

3Productivity

If multiple induction targets are operated simultaneously, then productivity is improved, but flicker is generated

Engineering Contradiction:
Improveoverall heating outputVSAvoidflicker
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system uses periodic switching to operate multiple induction targets sequentially rather than simultaneously. The control unit alternates between different targets in defined time intervals, which prevents the flicker effect that would be caused by simultaneous switching of multiple high-power loads, while still delivering the required overall heating output through continuous operation cycles.

Inventive Principle:
Principle #19Periodic action

4Ease of operation

If induction targets are operated without coordination, then ease of operation is improved, but acoustic quality deteriorates

Engineering Contradiction:
Improveindependent control of induction targetsVSAvoidacoustic coupling noises
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The control unit implements feedback control by continuously monitoring the operational state of each induction target and adjusting the switching sequence accordingly. This feedback mechanism ensures that induction targets are never operated simultaneously, thereby preventing coupling noises while maintaining the flexibility and ease of operation for the user to select and control different heating zones independently.

Inventive Principle:
Principle #23Feedback

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 effectively reduces acoustic coupling noises, ensures a comfortable operating environment, and maintains a stable power supply by minimizing flicker and allowing flexible adjustment of heating power, while maintaining reliable setpoint heating outputs.

Implementation Method 1

a detection unit for determining a coupling characteristic of a coupling between the induction targets, wherein the control unit is designed to evaluate the coupling characteristic and, in the event of a coupling between the first and second induction targets

Methodology Applied
Scientific EffectMagnetic coupling: Electromagnetic Induction

Implementation Method 2

a control unit for controlling and supplying energy to at least one first induction target from a first energy source and at least one second induction target from a second energy source

Methodology Applied
Scientific EffectInduction heating: Electromagnetic Induction

Implementation Method 3

acoustic coupling noises due to intermodulation between induction sources operating at different heating frequencies can be avoided

Methodology Applied
Scientific EffectIntermodulation:

Implementation Method 4

keep the average power drawn from the energy sources constant and/or advantageously to minimize and/or avoid flicker

Methodology Applied
Scientific EffectFlicker:

Data Source

PatentEP3641494B1Cooking device
Publication Date: 2022.03.23 BOSCH SIEMENS HAUSGERATE GMBH
  • EP3641494B1 patent drawingFigure 1a~1b
  • EP3641494B1 patent drawingFigure 2a~2b
  • EP3641494B1 patent drawingFigure 3a~3b

AI summary

To improve the control characteristics, a cooking appliance device (10), in particular a hob device, is proposed with a control unit (12) which is provided for controlling and supplying energy to at least one first induction target (14) from a first energy source and at least one second induction target (16) from a second energy source, and with a detection unit (18) for determining a coupling characteristic of a coupling between the induction targets (14, 16), wherein the control unit (12) is provided to evaluate the coupling characteristic and, in the case of a coupling between the first induction target (14) and the second induction target (16), to switch to at least one special operating state in order to at least reduce coupling noise by at least one special control of the induction targets (14, 16).