Induction Coil Resonance Frequency Calibration

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Solution Overview

Problem

Aerosol generating devices face challenges in maintaining a target temperature profile for the susceptor due to resistance deviations in the coil during production and assembly, leading to inconsistent heating performance.

Innovation Solution

The aerosol generating system includes a controller that applies a test voltage to the coil, measures the output current while changing the frequency of the test voltage, determines the frequency at which the output current becomes maximum, and applies an operating voltage with this determined frequency to the coil, ensuring optimal heating performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a coil is made according to a design standard, then the resonance frequency should match the stored value, but resistance deviation occurs during production and assembly causing the resonance frequency to vary

Engineering Contradiction:
Improveresistance deviationVSAvoidheating temperature consistency
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The system performs a preliminary measurement action by applying a test voltage to the coil and detecting its resonance frequency before actual heating operation. The controller stores the detected resonance frequency and uses it for subsequent heating operations, ensuring accurate heating despite manufacturing variations in the coil

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by measuring the actual resonance frequency of the coil through test voltage application and output current detection. The controller uses this feedback information to identify the correct operating frequency, compensating for resistance deviations that occur during production and assembly

Inventive Principle:
Principle #23Feedback

2Reliability

If the resonance frequency varies due to resistance deviation, then the heating temperature deviates from the target profile, but the system needs to maintain consistent heating performance

Engineering Contradiction:
Improveheating temperature consistencyVSAvoidresonance frequency variation
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The controller performs preliminary detection of the coil's resonance frequency by applying test voltages at different frequencies and measuring the output current. The resonance frequency corresponding to maximum output current is stored and used for subsequent heating operations, ensuring consistent heating performance despite manufacturing variations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the operating frequency parameter of the coil based on detected resonance characteristics. By adjusting the frequency of the voltage applied to the coil to match the detected resonance frequency, the system maintains optimal heating performance even when manufacturing precision varies

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a test voltage is applied to detect resonance frequency, then accurate heating can be achieved, but additional measurement and control steps are required

Engineering Contradiction:
Improveresonance frequency detectionVSAvoidcontrol process steps
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The controller performs multiple functions using the same hardware components: it detects resonance frequency by applying test voltages and measuring output current, then uses the same coil and controller for actual heating operations. This multi-functionality reduces the need for separate measurement and control systems

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own existing components (controller, coil, voltage source) to perform the resonance frequency detection and measurement. The controller that controls heating also performs the detection function, eliminating the need for external measurement devices and simplifying the overall system

Inventive Principle:
Principle #25Self-service

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 solution allows the aerosol generating system to maintain a target temperature profile for the susceptor even with resistance deviations in the coil, providing a consistent and optimal smoking experience.

Implementation Method 1

a coil surrounding the susceptor and heating the susceptor by generating a magnetic field when an alternating current voltage is applied

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a susceptor heating an aerosol generating article; a coil surrounding the susceptor and heating the susceptor by generating a magnetic field

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Data Source

PatentEP3836808B1Aerosol generating system
Publication Date: 2025.05.21 KT&G CO LTD
  • EP3836808B1 patent drawingFigure 1~4
  • EP3836808B1 patent drawingFigure 5~6
  • EP3836808B1 patent drawingFigure 7~8

AI summary

An aerosol generating device includes: a susceptor heating an aerosol generating article; a coil surrounding the susceptor and heating the susceptor by generating a magnetic field when an alternating current voltage is applied; and a controller which applies a test voltage to the coil in response to a user input, measures an output current of the coil while changing a frequency of the test voltage, determines a frequency at which the output current becomes maximum, and applies an operating voltage having the determined frequency to the coil.