Inductive Heater Calibration Using Curve Plateau and Hill Points
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing aerosol-generating devices face challenges in accurately monitoring and controlling the temperature of electrically operated heat sources to prevent overheating, which can lead to combustion of the aerosol-forming substrate and the generation of undesirable compounds.
Innovation Solution
A method for calibrating an inductive heating device that involves obtaining and smoothing calibration values, determining the first derivative, estimating a maximum value, and operating the device based on plateauing characteristics and hill point values to prevent overheating, using a controller to regulate temperature without continuous temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous temperature measurement is used to monitor heat source temperature, then temperature control accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses an intermediary substance (susceptor material) that indirectly indicates temperature through its magnetic properties rather than directly measuring temperature. The controller monitors changes in the magnetic characteristics of the susceptor material as it heats up, using these changes as a proxy for temperature measurement, thereby avoiding the need for direct temperature sensors in the heating element.
Solution Approach 2:
The patent replaces the mechanical/physical temperature measurement system (thermocouples, RTDs, or other temperature sensors) with an electromagnetic field-based detection system. By monitoring the magnetic properties of the susceptor material through electromagnetic induction, the system substitutes direct temperature sensing with indirect magnetic property measurement.
2Productivity
If inductive heating is used to heat aerosol-forming substrate, then heating efficiency is improved, but risk of overheating and combustion increases
Solution Approach 1:
The patent implements a feedback control system where the controller continuously monitors the magnetic properties of the susceptor material during heating and adjusts the heating power accordingly. When the susceptor material reaches a predetermined temperature indicated by specific magnetic property changes, the controller reduces or stops heating to prevent overheating and combustion of the aerosol-forming substrate.
Solution Approach 2:
The patent incorporates a susceptor material with specific magnetic properties into the aerosol-forming substrate before heating begins. This preliminary preparation allows the system to use the magnetic properties of the susceptor as an early warning indicator of approaching dangerous temperatures, enabling preventive control actions before overheating occurs.
3Speed
If calibration values are obtained without smoothing, then calibration speed is improved, but accuracy of temperature determination deteriorates
Solution Approach 1:
The patent applies periodic smoothing operations to the calibration values obtained during the calibration process. Rather than using raw instantaneous measurements, the system processes calibration data through smoothing algorithms that filter out noise and variations, providing more accurate temperature determination while maintaining acceptable calibration speed through efficient processing.
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 provides reliable temperature regulation, preventing overheating and ensuring safe operation by accurately determining critical temperature points, thereby avoiding the formation of undesirable compounds.
Implementation Method 1
inductive heating device for heating an aerosol-forming substrate
Implementation Method 2
smoothing the sequence of calibration values to obtain a sequence of smoothed calibration values
Data Source
Figure 1~2B
Figure 3
Figure 4~5
AI summary
A method of calibrating an inductive heating device for an aerosol-generating system is disclosed. The method comprises obtaining a sequence of calibration values of an inductive heating device for an aerosol-generating system, wherein the sequence of calibration values is associated with a calibration curve, smoothing the sequence of calibration values to obtain a sequence of smoothed calibration values, determining a first derivative of the sequence of smoothed calibration values, estimating a maximum value of the first derivative of the sequence of smoothed calibration values, determining at least one of a plateauing characteristic and a hill point value based on a first threshold associated with the estimated maximum value of the first derivative, and operating the inductive heating device in accordance with the determined at least one of a plateauing characteristic and a hill point value.