Induction Hob Control Unit for Flicker Reduction

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Solution Overview

Problem

Existing cooking appliances struggle to provide a continuous and efficient power output while minimizing flicker and intermodulation noise, which affects the stability and energy efficiency of heating processes.

Innovation Solution

A cooking appliance device with at least two heating frequency units and a control unit that adjusts the average output power using a duty cycle of a control signal, allowing for continuous power delivery and reducing flicker by operating one or both heating frequency units at specific frequencies and duty cycles, while maintaining a constant total output power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If heating frequency units are operated at high power output, then heating efficiency is improved, but flicker and intermodulation noise increase

Engineering Contradiction:
Improveheating efficiencyVSAvoidflicker and intermodulation noise
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies periodic action by switching heating frequency units on and off in defined time periods. The control unit operates heating frequency units with different frequencies in alternating time periods, ensuring that in each period at least one unit operates at a frequency that minimizes flicker and intermodulation noise while maintaining high average power output for efficient heating.

Inventive Principle:
Principle #19Periodic action

2Object-generated harmful factors

If heating frequency units are switched on and off frequently to reduce flicker, then flicker is reduced, but power output continuity deteriorates

Engineering Contradiction:
ImproveflickerVSAvoidpower output continuity
Core Design Contradiction:
Object-generated harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent merges multiple heating frequency units operating at different frequencies to achieve continuous power output. When one unit is switched off to reduce flicker, another unit operates to maintain power delivery, ensuring continuous heating while minimizing flicker effects through the combined operation of multiple units.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control unit ensures continuous useful action by configuring multiple heating frequency units such that when one unit is switched off during a time period, another unit operates to maintain power output. This continuous operation across multiple units eliminates gaps in heating while allowing individual units to operate at flicker-reducing frequencies.

Inventive Principle:
Principle #20Continuity of useful action

3Power

If multiple heating frequency units operate simultaneously at different frequencies, then power output is maintained, but intermodulation noise increases

Engineering Contradiction:
Improvepower outputVSAvoidintermodulation noise
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent uses periodic action by alternating the operation of heating frequency units with different frequencies in defined time periods. During each period, at least one unit operates at a frequency specifically selected to minimize intermodulation noise, while the periodic switching maintains average power output without continuous simultaneous operation of multiple frequency units.

Inventive Principle:
Principle #19Periodic 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 achieves a highly continuous and precise power output, reduces flicker, and enhances energy efficiency by operating near resonance frequencies, ensuring stable and uniform heating while adhering to regulatory standards.

Implementation Method 1

A heating frequency unit (10, 12) is to be understood as meaning an electrical unit that generates an oscillating electrical current, preferably with a frequency of at least 1 kHz, in particular of at least 10 kHz and advantageously of at least 20 kHz, to operate at least one heating unit

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

A heating unit is to be understood as meaning a unit that is intended to at least partially convert electrical energy into heat

Methodology Applied
Scientific EffectJoule Heating: Joule Heating

Implementation Method 3

In particular, the heating unit comprises a radiant heater, a resistance heater and/or preferably an induction heater, which is intended to convert electrical energy into heat indirectly via induced eddy currents

Methodology Applied
Scientific EffectEddy Currents: Eddy Currents

Data Source

PatentEP2469971B1Cooking device
Publication Date: 2016.11.16 BOSCH SIEMENS HAUSGERATE GMBH
  • EP2469971B1 patent drawingFigure 1~2
  • EP2469971B1 patent drawingFigure 3~4
  • EP2469971B1 patent drawingFigure 5

AI summary

The appliance has a control unit (14) for adjusting an average output power of two heat frequency units (10, 12) by utilizing a pulse duty factor of a control signal. The control unit reduces a flicker characteristic variable by utilizing the pulse duty factor. A cooktop plate (18) is made of glass ceramic, and three heating zones (20-24) are marked on the cooktop plate. The cooktop plate is arranged horizontally in an operational condition of an induction hob (16) for placing a cooking container. The control unit is integrated in a controlling-and regulating unit (32) of the induction hob. An independent claim is also included for a method for utilizing a cooking appliance.