Induction Cooking Control Unit Managing Intermodulation Noise

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Solution Overview

Problem

Existing cooking appliances, such as induction hobs, face challenges in achieving flexible and scalable average output power settings while minimizing intermodulation noise and flicker, especially when operating multiple heating frequency units.

Innovation Solution

A cooking appliance device with a control unit that periodically operates multiple heating frequency units in defined time intervals, selecting control types from a catalog to optimize output power and frequency settings, ensuring minimal fluctuations and compliance with flicker limits, thereby allowing flexible power adjustments and scalability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If multiple heating frequency units are operated simultaneously at different frequencies to avoid intermodulation noise, then intermodulation noise is reduced, but device complexity and control difficulty increase

Engineering Contradiction:
Improveintermodulation noiseVSAvoidcontrol unit complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The period duration is divided into multiple time intervals, with each interval assigned a specific control type from the catalog. This segmentation allows the control unit to manage multiple heating frequency units in a structured manner, reducing control complexity while maintaining low intermodulation noise through frequent switching between different frequency configurations

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heating frequency units are operated periodically with a defined period duration that is divided into time intervals. This periodic operation enables systematic cycling through different control types, ensuring intermodulation noise is minimized while providing a predictable and manageable control pattern that reduces overall system complexity

Inventive Principle:
Principle #19Periodic action

2Object-affected harmful factors

If heating frequency units are switched on and off frequently to minimize flicker, then flicker is reduced, but output power stability becomes more difficult to maintain

Engineering Contradiction:
ImproveflickerVSAvoidoutput power stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The control unit dynamically selects control types from the catalog for each time interval based on the desired average output power and flicker minimization requirements. This dynamic adaptation allows the system to maintain output power stability while frequently switching between different heating frequency unit configurations to minimize flicker

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control unit monitors the operating state of heating frequency units and adjusts the selection of control types accordingly to maintain both flicker minimization and output power stability. The feedback mechanism ensures that switching operations achieve flicker reduction while maintaining stable average output power

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If the system is designed to accommodate a large number of heating frequency units, then scalability is improved, but control complexity and calculation requirements increase

Engineering Contradiction:
ImprovescalabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control unit is designed with a universal catalog of control types that can be applied to any combination of heating frequency units. This universal approach allows the system to scale to a large number of units without increasing control complexity, as the same catalog-based selection process handles any configuration

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

Solution Approach 2:

The control unit calculates and determines control types for each time interval based on the specific operating requirements, using only the necessary subset of available control types from the catalog. This partial action approach avoids unnecessary computational overhead while maintaining scalability

Inventive Principle:
Principle #16Partial or excessive action

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 enables flexible setting of average output power and simple scalability to a large number of heating frequency units, minimizing intermodulation noise and flicker, thereby enhancing operating comfort and precision in heating operations.

Implementation Method 1

an induction hob with at least two heating frequency units (10, 12)... an induction cooktop... heating frequency unit is understood to be, in particular, an electrical unit that generates an oscillating electric current, preferably with a frequency of at least 15 kHz

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an induction heating element designed to convert electrical energy indirectly into heat via induced eddy currents

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Data Source

PatentEP2506666B1Cooking device
Publication Date: 2020.05.06 BOSCH SIEMENS HAUSGERATE GMBH
  • EP2506666B1 patent drawingFigure 1~2
  • EP2506666B1 patent drawingFigure 3a~3b
  • EP2506666B1 patent drawingFigure 3c~3d

AI summary

The device has a controlling unit designed such that two heating frequency units are operated together in a time period (t) that is divided into two time intervals (Ta, Tb). The controlling unit is designed to select a control type for each time interval, from a catalog of control types, and to determine frequencies (f1a, f2a, f1b, f2b) of control signals of the heating frequency units based on the selected control type under temporal stabilization of average output powers (P1, P2) of the frequency units. The control unit adjusts the output powers to selected target powers (Pobj1, Pobj2). An independent claim is also included for a method for operating a cooking device.