Susceptor Temperature Sensing via RLC Resonance Tracking
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Solution Overview
Problem
Existing aerosol generating devices face challenges in accurately determining the temperature of the susceptor without physical contact, which is crucial for controlling the heating of aerosol generating materials to prevent burning or charring.
Innovation Solution
The controller determines the temperature of the susceptor by analyzing the frequency characteristic of the RLC resonance circuit, specifically the resonant frequency and bandwidth of the peak frequency response, using passive or active electrical measurements to infer the susceptor's temperature without direct contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If contactless temperature measurement is implemented using a camera, then non-contact temperature monitoring is achieved, but the measurement is affected by surrounding temperature and requires calibration
Solution Approach 1:
The patent introduces an intermediary approach by using the RLC resonance circuit as a mediator between the heating system and temperature measurement. The resonance frequency serves as an indirect indicator of temperature, eliminating the need for direct thermal contact or external optical measurement, thereby avoiding calibration issues and environmental interference.
2Measurement precision
If a temperature sensor is inserted into the aerosol generating component, then direct temperature measurement is achieved, but the structure becomes more complex and cleaning is more difficult
Solution Approach 1:
The system uses the susceptor itself as the temperature sensing element. The susceptor's electrical properties (resonance frequency) inherently change with temperature, so no separate temperature sensor is needed. The heating component serves dual purposes: heating and temperature indication, simplifying the overall device structure.
Solution Approach 2:
The susceptor is designed to perform multiple functions: it serves as both the heating element (through inductive heating) and the temperature sensor (through resonance frequency measurement). This multi-functionality eliminates the need for separate temperature sensing components.
3Ease of manufacture
If the RLC resonance circuit operates at a fixed frequency, then the circuit design is simpler, but accurate temperature determination across different operating conditions is difficult
Solution Approach 1:
The system transitions from a fixed-frequency approach to a dynamic frequency adjustment approach. The control unit varies the excitation frequency to track the resonance peak, allowing the system to adapt to changing operating conditions and temperature ranges while maintaining measurement accuracy.
Solution Approach 2:
The patent changes the operating parameter from a fixed frequency to a variable frequency that tracks the resonance peak. By monitoring shifts in the resonance frequency and bandwidth, the system can accurately determine temperature across different operating conditions without compromising circuit simplicity.
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 method allows for precise temperature control of the susceptor, enhancing design freedom and ensuring the aerosol generating material is heated within safe temperature limits without physical contact, thus preventing combustion.
Implementation Method 1
aerosol generating device, the susceptor being for inductive heating by a RLC resonance circuit
Implementation Method 2
frequency characteristic of a peak of a frequency response of the RLC resonance circuit
Data Source
Figure 1
Figure 2a~2b
Figure 2c~3a
AI summary
Disclosed are methods and apparatus for determining a temperature of a susceptor of an aerosol generating device, the susceptor being for inductive heating by a RLC resonance circuit. The apparatus is arranged to: determine a frequency characteristic of a peak of a frequency response of the RLC resonance circuit; and determine, based on the determined frequency characteristic, the temperature of the susceptor. Also disclosed is an aerosol generating device comprising the apparatus.