Electromagnetic cooking device with automatic liquid heating and method of controlling cooking in the electromagnetic cooking device

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Solution Overview

Problem

Conventional microwave ovens with single, non-coherent magnetron sources often result in non-uniform heating due to the lack of tunability and coherence in microwave frequency distribution, leading to inefficiencies in cooking processes.

Innovation Solution

An electromagnetic cooking device with multiple coherent RF feeds that introduce electromagnetic radiation into a cavity, allowing for dynamic wave pattern control through separately controlled frequencies, phases, and amplitudes, enabling precise heating control by monitoring resonance shifts and adjusting power levels based on efficiency coefficients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single magnetron source is used to generate microwave radiation, then the device complexity is reduced, but the heating uniformity deteriorates

Engineering Contradiction:
Improvesource configurationVSAvoidheating uniformity
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent divides the single microwave source into multiple separate feeds (at least two feeds) that independently introduce microwave energy into the cavity. Each feed can be controlled separately in terms of power level, phase, and frequency, allowing the system to create more uniform heating patterns by distributing energy from multiple locations rather than relying on a single source.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic control of the microwave feeds by independently adjusting power levels, phases, and frequencies of each feed based on detected resonance conditions. The system monitors reflected power and VSWR in real-time and dynamically modifies feed parameters to maintain optimal heating uniformity as the cooking process progresses and resonance conditions change.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If multiple RF feeds with separate control are implemented, then heating uniformity is improved, but the device complexity increases

Engineering Contradiction:
Improveheating uniformityVSAvoidcontrol system
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent incorporates feedback mechanisms that monitor reflected power and voltage standing wave ratio (VSWR) from each feed. The controller uses this feedback information to automatically adjust power levels, phases, and frequencies of the feeds to maintain optimal resonance conditions and heating uniformity. This closed-loop control system manages the complexity by using sensor data to drive automated adjustments.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-diagnosis and self-adjustment by detecting resonance conditions through reflected power measurements and automatically modifying feed parameters without external intervention. The controller monitors the cooking process in real-time and autonomously optimizes heating uniformity by adjusting feed configurations based on detected conditions, reducing the need for manual control.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If resonance monitoring and dynamic adjustment are implemented, then cooking precision is improved, but the measurement and control difficulty increases

Engineering Contradiction:
Improvetemperature controlVSAvoidresonance detection
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent exploits electromagnetic resonance (a form of vibration in the electromagnetic field) within the cooking cavity to identify optimal heating conditions. By monitoring reflected power and VSWR, the system detects resonance frequencies and adjusts feed parameters to maintain resonance, which corresponds to optimal energy transfer and heating efficiency. This approach converts a complex measurement problem into a detectable physical phenomenon.

Inventive Principle:
Principle #18Mechanical vibration

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 solution ensures more uniform and efficient heating by maintaining coherence within the cavity, allowing for precise temperature control and even heating patterns, thereby improving cooking consistency and efficiency.

Implementation Method 1

A conventional microwave oven cooks food by a process of dielectric heating in which a high-frequency alternating electromagnetic field is distributed throughout an enclosed cavity. Microwave frequencies at or around 2.45 GHz cause dielectric heating primarily by absorption of energy in water.

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 2

A reception antenna for receiving reflected waves reflected from the substance to be cooked

Methodology Applied
Scientific EffectElectromagnetic wave reflection: Reflection

Implementation Method 3

The controller is further configured to determine and monitor a coefficient of variation of the efficiency, wherein the coefficient of variation is based on a standard deviation and a mean of the efficiency during a predetermined period of time; detect a specified temperature of the liquid based on changes in the coefficient of variation

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3563635B1Electromagnetic cooking device with automatic liquid heating and method of controlling cooking in the electromagnetic cooking device
Publication Date: 2022.09.28 PANASONIC HOLDINGS CORP
  • EP3563635B1 patent drawingFigure 1
  • EP3563635B1 patent drawingFigure 2
  • EP3563635B1 patent drawingFigure 3

AI summary

An electromagnetic cooking device and method of controlling the same is provided herein. The cooking device has a cavity in which a liquid is placed and a plurality of RF feeds configured to introduce electromagnetic radiation into the cavity for heating the liquid. A controller is provided and is configured to: analyze forward and backward power at the plurality of RF feeds to calculate efficiency; determine and monitor a coefficient of variation of the efficiency; detect a specified temperature of the liquid based on changes in the coefficient of variation; and adjust a power level of the electromagnetic radiation in response to detection of the specified temperature.