Multi-Feed Electromagnetic Cooking with Asymmetry Compensation
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Solution Overview
Problem
Conventional microwave ovens using a single, non-coherent magnetron source result in non-uniform heating of food due to the lack of tunability and coherence in microwave frequency emission, leading to inefficiencies in cooking processes.
Innovation Solution
An electromagnetic cooking device with multiple RF feeds that can control and measure electromagnetic radiation, allowing for the selection of resonant modes and phases to create optimized heating patterns within the enclosed cavity, using closed-loop regulation to adjust the radiation patterns for uniform cooking.
Engineering Contradictions & Design Principles
Engineering 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
Solution Approach 1:
The patent divides the single microwave source into multiple separate RF feeds (at least two), each capable of independent control. This segmentation allows different regions of the cavity to be heated independently, improving overall heating uniformity while maintaining manageable system complexity through modular architecture
Solution Approach 2:
The patent implements dynamic control of multiple RF feeds by selectively activating different feeds at different time intervals and adjusting their power levels. This dynamic operation allows the system to adapt to different food loads and cavity configurations, optimizing heating uniformity without requiring all feeds to operate simultaneously at full power
2Manufacturing precision
If mechanical stirrers and turntables are added to improve heating uniformity, then the heating uniformity improves, but the device complexity increases
Solution Approach 1:
The patent replaces mechanical stirring and rotating components with an electromagnetic field-based solution using multiple independently controlled RF feeds. The heating uniformity is achieved through electronic control of electromagnetic radiation distribution rather than mechanical movement, eliminating wear, noise, and complexity associated with mechanical systems
Solution Approach 2:
The patent employs periodic switching between different RF feeds to create time-varying electromagnetic field patterns within the cavity. By sequentially activating different feeds in a controlled sequence, the system achieves uniform heating distribution over time without requiring mechanical rotation or stirring components
3Manufacturing precision
If multiple RF feeds are used to create optimized resonant modes, then the heating uniformity improves, but the device complexity increases
Solution Approach 1:
The patent incorporates feedback control by monitoring the resonant modes excited in the cavity and adjusting the phase and amplitude of each RF feed accordingly. This closed-loop control ensures that the desired resonant modes are maintained, optimizing heating uniformity while automatically compensating for variations in food load and cavity conditions
Solution Approach 2:
The patent controls heating uniformity by dynamically adjusting key parameters of the RF feeds including frequency, phase, and amplitude. By changing these parameters in a coordinated manner across multiple feeds, the system optimizes the excited resonant modes to match the specific food load configuration, achieving uniform heating without requiring complex mechanical structures
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 over heating patterns, ensuring more even and efficient cooking by adjusting the sequence of resonant modes based on food load asymmetries and position, thereby improving cooking uniformity and energy delivery.
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.
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.
Implementation Method 3
The controller is configured to select a heating target corresponding to an amount of energy that is to be delivered to each symmetry plane in the enclosed cavity based in part upon the food load positioned in the enclosed cavity where the heating target includes a plurality of unrotated resonant modes
Data Source
AI summary
An electromagnetic cooking device includes a cavity in which a food load is placed, a plurality of RF feeds for introducing electromagnetic radiation into the enclosed cavity, and a controller configured to select a heating target including a plurality of unrotated resonant modes; detect asymmetries of the food load relative to a center of the enclosed cavity and select rotations for the plurality of unrotated resonant modes that compensate for the detected asymmetries of the food load to generate a plurality of optimized resonant modes; generate a heating strategy having a selected sequence of the optimized resonant modes; cause the RF feeds to excite the enclosed cavity with a selected set of phasors for a set of frequencies corresponding to each resonant mode of the selected sequence of optimized resonant modes; and monitor the created heating patterns using closed-loop regulation to selectively modify the sequence of optimized resonant modes.