RF Cooking Device with Coefficient-of-Variation Popcorn Detection

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Solution Overview

Problem

Conventional microwave ovens using magnetron-based sources for electromagnetic cooking suffer from non-uniform heating due to a single, non-coherent microwave source, leading to inefficiencies in cooking food.

Innovation Solution

An electromagnetic cooking device with multiple RF feeds and a controller that analyzes forward and backward power to calculate efficiency, detects the popping state of popcorn, and adjusts the power level to ensure even cooking by controlling the electromagnetic radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single magnetron-based microwave source is used, then the device complexity is reduced, but the heating uniformity deteriorates

Engineering Contradiction:

Improvenumber of microwave sourcesVSAvoidheating uniformity

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The single magnetron source is segmented into multiple independent solid-state RF sources (at least two), each capable of generating coherent microwave radiation. This segmentation allows independent control of each source to achieve uniform heating across different cavity zones while maintaining system functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically controls the phase, frequency, and amplitude of each RF source based on real-time efficiency measurements and coefficient of variation analysis. This dynamic adjustment enables the system to adapt to different cooking conditions and maintain heating uniformity throughout the cooking process.

Inventive Principle:

Principle #15Dynamics

2Stability of the object's composition

If multiple RF feeds are used to improve heating uniformity, then the heating uniformity is improved, but the device complexity increases

Engineering Contradiction:

Improveheating uniformityVSAvoidnumber of RF feeds and control systems

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The system implements feedback control by measuring forward and backward power at each RF feed, calculating efficiency, and using the coefficient of variation to determine when popping is complete. This feedback mechanism automates the control of multiple RF feeds, reducing the operational complexity despite the increased hardware configuration.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The controller performs multiple functions including power analysis, efficiency calculation, coefficient of variation determination, popping state detection, and power level adjustment. This multi-functionality consolidates the control of multiple RF feeds into a single intelligent controller, managing system complexity through functional integration.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If automatic popcorn detection is implemented, then the productivity is improved, but the measurement precision requirements increase

Engineering Contradiction:

Improveautomatic cooking controlVSAvoidcoefficient of variation measurement

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system periodically measures forward and backward power to calculate efficiency and determine the coefficient of variation. This periodic measurement approach, combined with threshold comparison over time, enables reliable automatic detection of popcorn popping completion while managing measurement precision requirements through statistical analysis.

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 enables precise control of electromagnetic radiation, resulting in more uniform heating and efficient cooking by monitoring the coefficient of variation in efficiency and adjusting power levels accordingly.

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 voltage applied to a high-voltage transformer results in a high-voltage power that is applied to a magnetron that generates microwave frequency radiation. The microwaves are then transmitted to an enclosed cavity containing the food through a waveguide.

Methodology Applied

Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentUS11503679B2Electromagnetic cooking device with automatic popcorn popping feature and method of controlling cooking in the electromagnetic device

Publication Date: 2022.11.15 PANASONIC HOLDINGS CORP

AI summary

An electromagnetic cooking device and method of controlling the same is provided herein. The cooking device has a cavity in which popcorn is placed and a plurality of RF feeds configured to introduce electromagnetic radiation into the cavity for popping the popcorn. 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 popping state of the popcorn based on changes in the coefficient of variation; and adjust a power level of the electromagnetic radiation in response to detection of the popping state.