Induction Cooktop Rectifier Fast-Recovery Diodes High-Frequency Efficiency

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Solution Overview

Problem

Induction heating devices, particularly induction hobs, face challenges in achieving high-frequency suitability and efficiency due to limitations in rectifier units used, which affect the effective utilization of electrical energy and heating performance.

Innovation Solution

The induction heating device employs faster-recovery rectifier elements and a heating frequency unit to convert low-frequency electrical energy into high-frequency alternating current, coupled with a resonance unit to optimize energy transfer and minimize switching losses, thereby enhancing efficiency and power delivery to induction heating elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If slow-recovery diodes are used in the rectifier unit, then the device structure is simple and cost-effective, but the high-frequency suitability and efficiency deteriorate

Engineering Contradiction:
Improverectifier unit simplicityVSAvoidenergy efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent changes the key parameter of the rectifier elements from slow-recovery diodes to faster-recovery rectifier elements. This parameter change enables the system to operate efficiently at higher frequencies while maintaining manufacturing feasibility, as the faster recovery time allows for higher switching frequencies without excessive energy loss.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamic control through the heating frequency unit that can adjust the operating frequency of the induction heating device. This dynamic frequency adjustment allows the system to optimize performance for different cooking requirements while maintaining energy efficiency through the faster-recovery rectifier elements.

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If faster-recovery rectifier elements are used, then high-frequency suitability and efficiency improve, but device complexity and cost increase

Engineering Contradiction:
Improveenergy efficiencyVSAvoidrectifier unit complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The faster-recovery rectifier elements serve multiple functions: they rectify the input voltage, enable high-frequency operation, and support the resonant circuit operation. This multi-functionality reduces the need for additional components that would otherwise be required to achieve high-frequency suitability, thereby limiting the increase in device complexity.

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

Solution Approach 2:

The patent introduces a resonant circuit as an intermediary between the rectifier unit and the induction heating element. This resonant circuit facilitates efficient energy transfer at high frequencies, allowing the faster-recovery rectifier elements to operate optimally while maintaining overall system efficiency and managing complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Power

If high-frequency alternating current is used, then heating performance and power delivery improve, but switching losses and energy waste increase

Engineering Contradiction:
Improvepower deliveryVSAvoidswitching losses
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent employs periodic switching of the heating frequency unit at optimized frequency intervals. By switching at carefully controlled periods that align with the resonant frequency of the circuit, the system achieves high power delivery while minimizing switching losses, as the faster-recovery rectifier elements can handle the switching transitions more efficiently.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The resonant circuit maintains continuous energy oscillation between the inductive and capacitive elements, ensuring that useful action continues throughout the cycle. This continuous resonant operation minimizes energy losses during switching transitions by maintaining smooth current and voltage waveforms, thereby achieving high power delivery with reduced switching losses.

Inventive Principle:
Principle #20Continuity of useful 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

This configuration improves the high-frequency suitability and efficiency of the induction heating device, allowing for effective use of high-frequency electrical energy and efficient power transmission to heating elements, resulting in improved performance and reduced energy losses.

Implementation Method 1

a rectifier unit (30), which is intended to convert current from an electrical energy source (18) into rectified current

Methodology Applied
Scientific EffectRectification: Diode

Implementation Method 2

a heating frequency unit (50), which is intended to convert low-frequency electrical energy into high-frequency alternating current

Methodology Applied
Scientific EffectFrequency conversion:

Implementation Method 3

an induction heating element, which is intended to be heated by induction effects, in particular induction of electric current and/or magnetic reversal effects

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 4

induction of electric current and/or magnetic reversal effects

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 5

electrical energy, in at least one operating mode in which the induction heating element is connected to a supply electronics into electromagnetic field energy, which is ultimately converted into heat in a suitable heating medium

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 6

a resonance unit (60), which is intended to form at least one partial resonance circuit with an induction heating unit (20)

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2648476B1Induction heating device
Publication Date: 2016.05.25 BOSCH SIEMENS HAUSGERATE GMBH
  • EP2648476B1 patent drawingFigure 1
  • EP2648476B1 patent drawingFigure 2
  • EP2648476B1 patent drawingFigure 3

AI summary

The invention relates to an induction heating device (12), in particular an induction cooktop device, with at least one rectifier unit (30) designed to rectify current from an electrical energy source (18). To improve high-frequency suitability and/or efficiency, it is proposed that the rectifier unit (30) includes at least one fast-repetition rectifier element (32, 34, 36, 38).