Susceptor Temperature Modeling for Multi-Frequency Induction Heating
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Solution Overview
Problem
Existing e-cigarettes face challenges in accurately controlling the temperature of the susceptor using inductive heating and detecting susceptor replacement.
Innovation Solution
An aerosol-generating device determines a temperature model for the susceptor by applying alternating magnetic fields at different frequencies, measuring electrical characteristics, and updating the model based on these values to estimate temperature and detect susceptor replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single frequency signal is applied to the coil for temperature estimation, then the device complexity is reduced, but the measurement precision of susceptor temperature is insufficient
Solution Approach 1:
The patent applies signals at multiple different frequencies to the coil and measures the corresponding electrical characteristics (impedance, current, voltage) at each frequency. By analyzing how these electrical parameters change with frequency, the system can more accurately estimate the susceptor temperature, as the electrical characteristics vary with temperature in a detectable manner across different frequencies.
Solution Approach 2:
The system continuously monitors the electrical characteristics of the susceptor at multiple frequencies and uses this feedback information to update and refine the temperature estimation. This feedback mechanism allows the controller to track temperature changes dynamically and adjust heating parameters accordingly, improving measurement precision through iterative refinement.
2Measurement precision
If electrical characteristics at multiple frequencies are measured, then the temperature model accuracy is improved, but the loss of time for model determination increases
Solution Approach 1:
The patent pre-establishes the relationship between electrical characteristics at multiple frequencies and susceptor temperature through calibration or theoretical modeling. This preliminary work creates a lookup table or mathematical model that allows rapid temperature estimation during operation without requiring real-time multi-frequency measurements, thus reducing the time loss while maintaining accuracy.
Solution Approach 2:
Instead of continuously measuring at all possible frequencies, the system selects a limited set of optimal frequencies that provide sufficient temperature discrimination. This partial action approach maintains measurement precision while significantly reducing the time required for model determination compared to exhaustive frequency scanning.
3Reliability
If the temperature model is frequently updated, then the reliability of temperature control is improved, but the productivity of device operation is reduced
Solution Approach 1:
The system updates the temperature model periodically rather than continuously, at predetermined intervals or under specific conditions (e.g., when temperature thresholds are reached or after a certain number of heating cycles). This periodic updating maintains reliability by ensuring the model remains current while minimizing disruptions to continuous operation and preserving productivity.
Solution Approach 2:
The temperature model update frequency is made dynamic rather than static. The system adjusts when and how often to update based on operating conditions, such as increasing update frequency when rapid temperature changes are detected or decreasing it during stable operation phases. This dynamic approach balances reliability requirements with productivity maintenance.
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
Accurately estimates susceptor temperature and detects susceptor replacement, enhancing temperature control and device functionality.
Implementation Method 1
an alternating magnetic field is generated
Implementation Method 2
The temperature of the susceptor may increase due to eddy currents generated in the susceptor
Implementation Method 3
to heat a cigarette using an inductive heating scheme
Data Source
AI summary
A method, performed by an aerosol-generating device, of determining a temperature model of a susceptor, includes applying a first signal having a first frequency to a coil of a heater so that an alternating magnetic field is generated, determining a first value of an electrical characteristic of a susceptor indicated by the first signal, applying a second signal having a second frequency to the coil of the heater so that an alternating magnetic field is generated, determining a second value of the electrical characteristic of the susceptor indicated by the second signal, and determining a first temperature model for the susceptor based on the first value and the second value, wherein the first temperature model may be a model used for determining a temperature of the susceptor based on the electrical characteristic of the susceptor.