Multi-Feed Electromagnetic Cooking Device with Coherent Heating Control
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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 processes.
Innovation Solution
An electromagnetic cooking device with multiple RF feeds and a controller that analyzes forward and backward power to calculate efficiency, determines the coefficient of variation, and adjusts the power level to achieve uniform heating by detecting changes in the heating state, allowing for coherent control of electromagnetic radiation within the cooking cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single magnetron-based microwave source is used, then the device complexity is reduced, but the heating uniformity deteriorates
Solution Approach 1:
The patent divides the single magnetron source into multiple independent RF feeds (at least two separate RF sources). Each RF feed can be independently controlled in terms of phase and amplitude, allowing the system to create multiple electromagnetic field patterns simultaneously. This segmentation enables different regions of the cavity to be heated more uniformly by exploiting constructive and destructive interference patterns between the multiple sources.
Solution Approach 2:
The patent introduces dynamic control of the RF feeds by varying the phase and amplitude of each feed independently over time. The controller adjusts these parameters to create time-varying electromagnetic field distributions that move energy around the cavity, preventing static heating patterns and improving overall uniformity. This dynamic adjustment allows the system to adapt to different loading conditions and maintain optimal heating distribution.
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
Solution Approach 1:
The patent makes the RF feeds multi-functional by enabling each feed to serve multiple purposes: they act as both heating sources and sensing elements. The same RF feeds that deliver microwave energy for heating also provide the signals used to measure forward and backward power, calculate efficiency, and detect heating state through coefficient of variation analysis. This eliminates the need for separate sensing systems and reduces overall device complexity despite having multiple feeds.
Solution Approach 2:
The patent implements a feedback control system where the controller continuously monitors the coefficient of variation of efficiency across multiple RF feeds and adjusts the phase and amplitude of the feeds accordingly. This closed-loop control automatically compensates for variations in heating distribution, maintaining uniform heating conditions without requiring complex mechanical stirrers or turntables, thereby managing device complexity through intelligent control rather than additional mechanical components.
3Stability of the object's composition
If mechanical solutions like stirrer and turntable are added, then the heating uniformity is improved, but the device complexity and loss of time increase
Solution Approach 1:
The patent replaces mechanical stirring and rotating mechanisms with an electromagnetic field-based solution. By using multiple RF feeds with independently controllable phase and amplitude, the system creates dynamic electromagnetic field patterns that simulate the effect of mechanical stirring without any moving parts. This substitution eliminates mechanical wear, reduces maintenance requirements, and removes the time loss associated with mechanical components while achieving similar or better heating uniformity.
4Device complexity
If a non-tunable magnetron source is used, then the device complexity is reduced, but the adaptability to different cooking conditions deteriorates
Solution Approach 1:
The patent enables frequency tuning and parameter adjustment by allowing each RF feed to operate at variable frequencies and with adjustable phase and amplitude. The controller can modify these parameters in real-time based on detected heating conditions, efficiency measurements, and coefficient of variation data. This parameter flexibility allows the system to adapt to different food types, cavity loading conditions, and cooking objectives without requiring complex mechanical adjustments or multiple fixed-frequency sources.
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 enables more even and efficient heating by maintaining coherence in electromagnetic wave patterns, ensuring consistent cooking results and optimizing energy use.
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. A sub-band of the radio frequency spectrum, microwave frequencies at or around 2.45 GHz cause dielectric heating primarily by absorption of energy in water.
Implementation Method 2
microwave frequencies at or around 2.45 GHz cause dielectric heating primarily by absorption of energy in water
Data Source
AI summary
An electromagnetic cooking device and method of controlling the same is provided herein. The cooking device includes 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 heating state in 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 heating state.