Cooking Vessel Temperature Sensing via Induction Resonance Modulation
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Solution Overview
Problem
Existing methods for precisely controlling cooking processes in inductively heatable cooking vessels struggle to accurately determine food temperature, especially when cooking foods containing starch and protein, due to the difficulty in correlating food temperature with the cooking vessel's base temperature, necessitating a reliable and cost-effective means to transmit sensor data from a dedicated food temperature sensor to a reading device.
Innovation Solution
A method and system that utilize a sensor device with an antenna inductively coupled to the induction heating coil, where the impedance is modulated to transmit data by changing the resonant frequency of the self-resonant oscillation circuit, allowing for reliable and cost-effective data transmission from the sensor to a reading device, which decodes the data based on changes in the resonant frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated sensor is provided for measuring the temperature of the food being cooked, then the temperature measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent combines the temperature sensor with the cooking vessel structure itself, integrating the sensing function into the vessel rather than using a separate standalone sensor. This merging approach maintains measurement precision while reducing overall device complexity by eliminating separate sensor mounting structures and wiring systems.
Solution Approach 2:
The cooking vessel is designed to serve multiple functions: it acts as both the cooking container and the sensor housing/protective structure. The vessel's bottom or wall structure simultaneously provides mechanical containment and sensor protection, reducing the need for additional components and simplifying the overall device architecture.
2Ease of operation
If data is transmitted wirelessly from the sensor to the reading device, then the ease of operation is improved, but the reliability of data transmission deteriorates
Solution Approach 1:
The patent introduces an intermediate communication mechanism where the sensor data is first transferred to the control unit via a reliable connection (such as conductive contact through the vessel structure), and then the control unit transmits the data wirelessly to the reading device. This intermediary approach ensures data integrity through the reliable first-stage transmission while maintaining user convenience through wireless final-stage transmission.
Solution Approach 2:
The system incorporates feedback mechanisms where the control unit verifies data reception and transmission status, ensuring data integrity during wireless communication. The control unit can request retransmission if data is not properly received, thereby maintaining reliability while preserving the wireless ease of operation.
3Reliability
If additional receiving antennas or devices are added for data reception, then the reliability of data transmission is improved, but the device complexity increases
Solution Approach 1:
The control unit of the induction heating device is designed to perform multiple functions: it controls the heating process, processes sensor data, and acts as the receiving device for wireless data transmission. This multi-functionality eliminates the need for separate receiving antennas or devices, maintaining reliability through integrated processing while avoiding additional complexity from extra components.
Solution Approach 2:
The patent merges the control unit functions with the data reception function, combining what would traditionally be separate components (heating control and data reception) into a single integrated unit. This consolidation maintains the reliability of data reception while reducing device complexity by eliminating redundant components and simplifying the system architecture.
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
Enables precise and reliable transmission of food temperature data from the sensor to the reading device, allowing for accurate control of the cooking process without the need for additional receiving antennas or devices, thereby improving cooking process control while maintaining cost-effectiveness.
Implementation Method 1
a converter generates a high-frequency drive voltage from a mains AC voltage, the high-frequency drive voltage being applied to a resonant circuit with an induction heating coil in order to generate a high-frequency magnetic alternating field for heating the cooking vessel
Implementation Method 2
an impedance of an antenna which is inductively or magnetically coupled to the induction heating coil and which is assigned to the cooking vessel or can be part of the cooking vessel is changed depending on data to be transmitted from the sensor, i.e. load modulation is carried out. The change in impedance causes a change in the resonant frequency of the self-resonant oscillation.
Implementation Method 3
the high-frequency magnetic alternating field is used to supply operating energy to a circuit which is designed to acquire the data from the sensor
Data Source
AI summary
In a method for transferring data of a sensor (1), which is associated with a cooking vessel that can be inductively heated, to a reading device (3), a high-frequency control voltage (UA) is produced from a mains alternating voltage (UN) by means of a converter (4), wherein the high-frequency control voltage is applied to a resonant circuit (15) having an induction heating coil (5) in order to produce a high-frequency alternating magnetic field in order to heat the cooking vessel. The method comprises the following steps: interrupting the application of the high-frequency control voltage to the resonant circuit during a specified first time period around a zero crossing of the mains alternating voltage in order to cause a self-resonant oscillation of the resonant circuit; changing an impedance of an antenna (6), which is inductively coupled to the induction heating coil and which is associated with the cooking vessel, according to data of the sensor to be transferred, during a second time period that lies within the first time period; and decoding the transferred data of the sensor in the reading device, in that a resonance frequency, in particular a resonance frequency change, of the self-resonant oscillation of the resonant circuit is evaluated.