Induction Cooking Temperature Control via Resonant Frequency
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Solution Overview
Problem
Conventional cooking appliances, particularly induction cooking devices, face challenges in accurately and continuously measuring the temperature of cookware bases, leading to delayed and inaccurate temperature control, which affects cooking quality and efficiency, especially in professional gastronomy where precise temperature management is crucial.
Innovation Solution
The method involves measuring the resonant frequency of an induction measuring oscillating circuit interacting with the cookware, using a support element with attached temperature sensors to determine absolute temperature values, and calculating temperature calibration values through a series of step responses, allowing for real-time temperature control without the need for pre-calibration of each cookware piece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If temperature sensors are attached underneath the cooking surface to measure temperature, then temperature detection capability is improved, but measurement precision deteriorates due to thermal conductivity delays and thickness of the cooking surface
Solution Approach 1:
The patent introduces an intermediary approach by using the cooking vessel base itself as a temperature sensing element through inductive coupling. Instead of measuring temperature directly through the cooking surface (which introduces thermal delays), the system measures the electrical properties of the vessel base material that change with temperature, providing direct temperature information without thermal conduction delays.
Solution Approach 2:
The patent replaces the mechanical/thermal measurement system (temperature sensors attached to the cooking surface that rely on thermal conduction) with an electromagnetic measurement system. By using inductive heating and measuring changes in electrical properties of the vessel base, the system eliminates the thermal conduction path and directly senses temperature through electromagnetic interactions.
2Loss of information
If conventional thermal cooktops use temperature sensors on the cooking surface, then temperature monitoring is enabled, but temperature control responsiveness deteriorates due to thermal inertia and delay
Solution Approach 1:
The patent performs preliminary action by measuring the electrical properties of the vessel base material before and during heating to establish a baseline relationship between electrical properties and temperature. This pre-established relationship allows for real-time temperature determination without waiting for thermal equilibrium or experiencing thermal delays during the cooking process.
Solution Approach 2:
The patent substitutes the slow thermal measurement system with a fast electromagnetic measurement system. By measuring changes in electrical properties (conductivity, permeability) of the vessel base through inductive coupling, the system obtains immediate temperature information without the thermal inertia inherent in conventional thermal sensors, eliminating temperature control delays.
3Reliability
If induction cooking appliances use resonant frequency measurement for temperature control, then temperature control capability is improved, but device complexity increases due to calibration requirements
Solution Approach 1:
The patent implements self-service by enabling the system to automatically determine temperature calibration characteristics during normal cooking operations. Instead of requiring separate calibration procedures or pre-calibration of each vessel, the system continuously measures electrical properties during heating and autonomously establishes the temperature-electrical property relationship, eliminating complex calibration workflows.
Solution Approach 2:
The patent ensures continuity of useful action by performing temperature measurement and calibration simultaneously during normal cooking operations. The system continuously measures electrical properties of the vessel base while heating, allowing temperature control functionality to be established and maintained without interrupting the cooking process or requiring separate calibration steps.
4Measurement precision
If multiple temperature calibration values are determined for different cookware, then measurement precision is improved, but productivity deteriorates due to time-consuming calibration processes
Solution Approach 1:
The patent performs preliminary action by establishing temperature calibration characteristics during the initial heating phase of cooking. By measuring electrical properties at different temperature points as the vessel heats up, the system pre-determines calibration values without requiring separate calibration steps, allowing immediate transition to accurate temperature control during the cooking process.
Solution Approach 2:
The patent maintains continuity of useful action by continuously measuring electrical properties throughout the heating process to determine calibration values. Instead of stopping cooking for calibration, the system performs measurements continuously as the vessel heats, converting what would be idle calibration time into productive cooking time, thereby maintaining both accuracy and efficiency.
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 approach enables continuous and accurate temperature control of cookware during cooking, reducing the need for manual calibration and minimizing delays, thereby improving cooking efficiency and consistency across various cookware types.
Implementation Method 1
an induction coil under the cooking surface, by means of which an alternating magnetic field is generated. The alternating magnetic field in turn induces, among other things, eddy currents in the induction cookware, particularly in its base, which, in addition to hysteresis and hysteresis losses, contribute to the heating of the cookware
Implementation Method 2
The alternating magnetic field in turn induces, among other things, eddy currents in the induction cookware, particularly in its base
Implementation Method 3
eddy currents in the induction cookware, particularly in its base, which, in addition to hysteresis and hysteresis losses, contribute to the heating of the cookware
Implementation Method 4
provide a measuring device with a measuring coil below the cooking surface in the area of the induction coil, by means of which an induction measuring resonant circuit is generated, which interacts with the cooking utensil
Implementation Method 5
an induction measuring resonant circuit is generated, which interacts with the cooking utensil. This resonant measuring circuit is characterized by a resonant frequency that depends, among other things, on the permeability or inductance of the cooking utensil
Data Source
Figure 1~2
Figure 3a~3b
Figure 4a~4b
AI summary
The invention relates to a method for determining and regulating the temperature of an article with inductive properties which is heated inductively by means of an induction device, wherein the induction device contains an induction coil, means for producing an induction resonant circuit and a support element arranged above the induction coil and having a first side, which acts as support face for the article, and a second side, which is directed towards the inductive coil. At least one temperature sensor is fitted to the second side. The resonant frequency of the induction resonant circuit is measured via detection means and the temperature of the article is calculated from the measured resonant frequency, wherein the resonant frequency is related to the temperature of the article by virtue of a mathematical function, and the function is determined by determining at least two absolute temperature calibration values of the article at respectively different resonant frequencies. The temperature calibration values are calculated from temperature measured values of the sensor.