RF Defrosting Apparatus with Impedance-Based Duration Control
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Solution Overview
Problem
Conventional capacitive food defrosting systems rely on manual timers and lack adaptive control, leading to inefficient defrosting operations due to changing impedance of the food load during the process, which can result in over or under-defrosting.
Innovation Solution
A system utilizing a radio frequency (RF) signal source, a variable impedance network, and a controller to dynamically adjust the defrosting duration based on the impedance matching between the RF signal source and the electrode, allowing for real-time monitoring and control of the defrosting process to ensure precise temperature achievement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If manual timer is used to control defrosting operation, then operation duration can be determined, but defrosting precision deteriorates due to impedance changes during the process
Solution Approach 1:
The system continuously monitors the impedance of the food load during defrosting and uses this feedback to dynamically adjust the RF power delivery. The controller compares the measured impedance against expected values and modifies the power output accordingly, ensuring precise defrosting control despite impedance changes throughout the process.
Solution Approach 2:
The patent implements dynamic control of the defrosting process by continuously adjusting RF power delivery based on real-time impedance measurements. Instead of using a fixed timer, the system adapts the power level and duration dynamically to match the changing electrical properties of the food load as it thaws, achieving both time efficiency and precision.
2Device complexity
If fixed RF power is supplied to the electrode, then system simplicity is maintained, but energy absorption efficiency deteriorates due to impedance mismatch
Solution Approach 1:
The system measures the impedance of the food load and uses this information to adjust RF power delivery in real-time. This feedback mechanism ensures that the food load consistently absorbs maximum energy from the RF field, optimizing heating efficiency without requiring complex additional hardware.
Solution Approach 2:
The controller dynamically changes the RF power delivery parameters (amplitude, duration) based on the measured impedance of the food load. By adjusting these parameters in response to impedance changes, the system maintains optimal energy transfer efficiency throughout the defrosting process.
3Reliability
If defrosting operation continues for extended period, then complete defrosting is achieved, but energy waste increases due to over-defrosting
Solution Approach 1:
The system continuously monitors impedance during defrosting and uses this feedback to detect when the defrosting process is complete. When the impedance reaches a threshold indicating full defrosting, the system automatically stops power delivery, ensuring reliable completion while preventing energy waste from over-defrosting.
Solution Approach 2:
The defrosting system monitors its own process state through impedance measurements and autonomously determines when to stop operation. This self-regulating capability ensures the food is completely defrosted without requiring external intervention or risking energy waste from extended operation.
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 system ensures efficient and precise defrosting by dynamically adjusting the RF energy delivery based on the load's impedance changes, allowing for accurate prediction of completion time and maintaining optimal energy absorption, thus improving defrosting efficiency and user experience.
Implementation Method 1
a radio frequency signal source configured to supply a radio frequency signal; an electrode coupled to the radio frequency signal source
Implementation Method 2
a variable impedance network that includes at least one variable passive component, wherein the variable impedance network is coupled between the radio frequency signal source and the electrode
Data Source
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AI summary
A system is configured to perform an operation that results in increasing a thermal energy of a load. The system includes a radio frequency signal source configured to supply a radio frequency signal, an electrode coupled to the radio frequency signal source, and a variable impedance network that includes at least one variable passive component. The variable impedance network is coupled between the radio frequency signal source and the electrode. The system includes a controller configured to determine an operation duration based upon a configuration of the variable impedance network, and to cause the radio frequency signal source to supply the radio frequency signal for the operation duration.