Induction Hob Control Entity Using Resonance Capacitor Voltage Sampling

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Solution Overview

Problem

Existing induction hobs require a current transducer to determine peak current and power factor, increasing the total costs and footprint of the power circuit board.

Innovation Solution

The induction hob employs a control entity that calculates peak current and phase delay using discrete mathematical transformations on sampled resonance capacitor voltage information, eliminating the need for a current transducer and reducing costs and footprint by utilizing existing resources like microprocessors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a current transducer is used to determine peak current and power factor, then measurement accuracy is improved, but device complexity and cost increase

Engineering Contradiction:
Improvepeak current measurement accuracyVSAvoidpower circuit board complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the physical current transducer (electrical measurement device) with a mathematical calculation system. The control entity uses discrete mathematical transformations on resonance capacitor voltage samples to compute peak current and phase delay, eliminating the need for physical transducer hardware and reducing circuit board complexity while maintaining measurement accuracy

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

Solution Approach 2:

The patent introduces resonance capacitor voltage as an intermediary measurement parameter. Instead of measuring current directly, the system measures the voltage across the resonance capacitor and uses mathematical transformations to derive current information, thereby avoiding the need for a current transducer

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a current transducer is used to determine peak current and power factor, then measurement accuracy is improved, but manufacturing cost increases

Engineering Contradiction:
Improvepower factor measurement accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive current transducer hardware with inexpensive mathematical calculations performed by the control entity. The software-based approach using discrete mathematical transformations on existing voltage samples eliminates the need for costly physical components, significantly reducing manufacturing costs while maintaining measurement precision

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes physical measurement hardware (current transducer) with computational methods (discrete mathematical transformations). This replacement eliminates expensive components and reduces bill of materials costs, making the induction hob more cost-effective to manufacture

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

3Measurement precision

If a current transducer is used to determine peak current and power factor, then measurement accuracy is improved, but footprint of power circuit board increases

Engineering Contradiction:
Improvecurrent amplitude measurement accuracyVSAvoidpower circuit board footprint
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent extracts and removes the current transducer component from the power circuit board. By using mathematical calculations on existing resonance capacitor voltage samples, the system eliminates the physical transducer hardware, thereby reducing the footprint of the power circuit board while maintaining current measurement accuracy

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the current measurement function into the existing control entity and voltage sampling system. Instead of adding a separate transducer component, the system combines current information extraction with the existing resonance capacitor voltage measurement and control logic, reducing overall circuit board footprint

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 approach reduces the overall costs and footprint of the power circuit while maintaining accurate calculations of current amplitude and phase delay, minimizing estimation inaccuracies and noise influence.

Implementation Method 1

induction coil placed below a hob plate in order to heat a piece of cookware

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Induction hobs for preparing food are well known in prior art

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 3

oscillating circuit portion comprising at least one resonance capacitor which is associated with a resonance capacitor voltage

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 4

oscillating circuit portion comprising at least one resonance capacitor

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3534673B1Induction hob and method for operating an induction hob
Publication Date: 2021.09.15 ELECTROLUX APPLIANCES
  • EP3534673B1 patent drawingFigure 1~2
  • EP3534673B1 patent drawingFigure 3~4
  • EP3534673B1 patent drawing

AI summary

The invention relates to an induction hob comprising a circuitry (1a) for powering at least one induction coil (6), the circuitry (1a) comprising a power circuit portion (7) with at least one switching element (4, 5) adapted to provide pulsed electric power to said induction coil (6) and an oscillating circuit portion (9) comprising at least one resonance capacitor (9.1, 9.2) which is associated with a resonance capacitor voltage, said induction coil (6) being electrically coupled with said power circuit portion (7) and said oscillating circuit portion (9), wherein said induction hob comprises a control entity (10), said control entity (10) being configured to provide and/or receive resonance capacitor information, specifically, sampled resonance capacitor voltage values, applying a discrete mathematical transformation to the resonance capacitor information thereby obtaining modified resonance capacitor information, said control entity (10) being further configured to calculate first and second electrical information related to the induction coil (6), specifically information regarding the amplitude of the electric current (Ic) provided through said induction coil (6) and information regarding the phase delay between the electric current (Ic) provided through said induction coil (6) and the voltage applied to the induction coil (6) based on said modified resonance capacitor information.