Dual-Resonance Inductive Heating for Independent Aerosol Substrate Control

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Solution Overview

Problem

Existing aerosol-generating devices with multiple inductor coils struggle to heat one portion of an aerosol-generating article without indirectly heating adjacent portions, due to the shared inductive heating mechanism.

Innovation Solution

The aerosol-generating device employs an LC circuit with a first and second inductor coil, each with a distinct resonance frequency, allowing for independent control of the heating of different portions of the susceptor arrangement using AC currents at specific frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple inductor coils are used to heat different portions of the susceptor arrangement, then the ability to heat different portions independently is improved, but cross-heating of adjacent portions occurs due to the shared inductive heating mechanism

Engineering Contradiction:
Improveindependent heating controlVSAvoidcross-heating
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by operating each inductor coil at its own resonant frequency. The controller is configured to drive the first inductor coil at a first resonant frequency and the second inductor coil at a second resonant frequency, which are different from each other. This frequency differentiation allows independent control of heating in different portions of the susceptor arrangement while minimizing cross-heating interference between adjacent portions.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a single inductor coil is used for heating, then the device structure is simpler, but the ability to control temperature of different portions independently is lost

Engineering Contradiction:
Improveheater structureVSAvoidtemperature control precision
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies segmentation by dividing the single inductor coil into multiple separate inductor coils, where each coil is responsible for heating a specific portion of the susceptor arrangement. The device includes a first inductor coil for generating a first varying magnetic field to heat a first portion, and a second inductor coil for generating a second varying magnetic field to heat a second portion. This segmentation enables independent temperature control of different portions while maintaining manageable device complexity.

Inventive Principle:
Principle #1Segmentation

3Productivity

If multiple inductor coils operate simultaneously at the same frequency, then heating efficiency is improved, but interference between coils causes unstable heating

Engineering Contradiction:
Improveheating efficiencyVSAvoidheating stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent resolves the interference issue by changing the operating frequency parameter for each inductor coil. Each coil operates at its own resonant frequency, which is determined by its inductance and capacitance values. This frequency separation eliminates electromagnetic interference between simultaneously operating coils, ensuring stable and reliable heating while maintaining high heating efficiency through parallel operation.

Inventive Principle:
Principle #35Parameter changes

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 approach enables precise temperature control of separate portions of the aerosol-forming substrate, minimizing cross-heating and optimizing the generation of aerosol with desired characteristics.

Implementation Method 1

The inductor generates a varying magnetic field to generate eddy currents and hysteresis losses in the susceptor, causing the susceptor to heat up

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The inductor generates a varying magnetic field to generate eddy currents and hysteresis losses in the susceptor

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 3

The inductor generates a varying magnetic field to generate eddy currents and hysteresis losses in the susceptor

Methodology Applied
Scientific EffectHysteresis losses: Hysteresis

Implementation Method 4

an inductive heater is used rather than a resistive heating element

Methodology Applied
Scientific EffectInductive heating: Induction Heating

Implementation Method 5

The resonance frequency of an LC circuit depends upon the inductance of the inductor coil of the LC circuit and upon the capacitance of the capacitor of the LC circuit

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3993656B1Aerosol-generating device comprising an inductive heating arrangement comprising first and second LC circuits having different resonance frequencies
Publication Date: 2025.05.14 PHILIP MORRIS PRODUCTS SA
  • EP3993656B1 patent drawingFigure 1
  • EP3993656B1 patent drawingFigure 2
  • EP3993656B1 patent drawingFigure 3~4

AI summary

An aerosol-generating device comprising: an inductive heating arrangement (501) configured to heat an aerosol-forming substrate, the inductive heating arrangement comprising: a susceptor arrangement (310) that is heatable by penetration with a varying magnetic field to heat the aerosol-forming substrate; a first LC circuit, the first LC circuit (510) at least comprising a first inductor coil (512) and a first capacitor (514), wherein the first LC circuit has a first resonance frequency; and a second LC circuit (520), the second LC circuit at least comprising a second inductor coil (522) and a second capacitor (524), wherein the second LC circuit has a second resonance frequency different from the first resonance frequency of the first LC circuit. The inductive heating arrangement (501) further shows a first transistor (516), such as a FET, connected to the first LC circuit (510) and a second transistor (526) connected with the second LC circuit (520). The first transistor (516) is configured for controlling operation (heating) of the first LC circuit (510). The second transistor (526) is configured for controlling operation (heating) of the second LC circuit (520). An aerosol-generating system comprising the aerosol-generating device and an aerosol-generating article comprising an aerosol- forming substrate.