Susceptor Inductive Heating Circuit for Rapid Aerosol Substrate Warmup
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Solution Overview
Problem
Conventional smoking articles rely on combustion for flavor and aroma delivery, which is inefficient and produces harmful distillation and pyrolysis products, while alternative methods require external power sources and larger devices for aerosol generation.
Innovation Solution
An inductive heating device with a DC power source, Class-E power amplifier, and LC load network that uses a helically wound inductor coil to inductively couple with a magnetically permeable susceptor, allowing for efficient heat transfer to an aerosol-forming substrate without an external power supply, enabling rapid and on-demand aerosol generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If combustion is used for heating the aerosol-forming substrate, then high temperature heating is achieved, but harmful distillation and pyrolysis products are generated and energy efficiency is low
Solution Approach 1:
The patent replaces the combustion-based heating system with an inductive heating system using a susceptor and electromagnetic field. The susceptor converts electromagnetic energy directly into heat through hysteresis and eddy current losses, eliminating the need for combustion and the associated harmful distillation and pyrolysis products while achieving rapid heating to required temperatures
Solution Approach 2:
The patent changes the heating mechanism from thermal combustion to electromagnetic induction, fundamentally altering the energy conversion parameters. The susceptor material properties (magnetic permeability, electrical conductivity) are optimized to convert electromagnetic field energy into heat efficiently, avoiding the chemical reactions that produce harmful substances
2Ease of operation
If a combustible heating element is used to heat air over heat-activated elements, then aerosol generation is achieved, but the device requires external power supply and larger size
Solution Approach 1:
The susceptor serves a dual function: it is both the heating element and the energy conversion device. When exposed to the alternating magnetic field from the induction source, the susceptor self-heats through electromagnetic induction, eliminating the need for separate external power supplies or combustible heating elements
Solution Approach 2:
The patent merges the susceptor with the aerosol-forming substrate, integrating the heating function directly into the substrate structure. This consolidation eliminates separate heating components and external power requirements, simplifying the overall device architecture
3Productivity
If inductive heating with susceptor is used, then rapid heat generation is achieved, but the device requires compact design with integrated power source
Solution Approach 1:
The inductive heating system uses periodic alternating magnetic fields at high frequency to generate heat rapidly in the susceptor. The Class-E power amplifier generates these high-frequency alternating currents, enabling fast heating cycles that can be turned on and off quickly, providing rapid and controllable heat generation
Solution Approach 2:
The patent optimizes the electrical parameters of the LC load network and power amplifier to operate at high frequency with low ohmic load, maximizing the efficiency of energy transfer to the susceptor. This enables rapid heating while maintaining compact dimensions suitable for portable devices
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
The device provides efficient, compact, and clean heating, reaching temperatures of 350-400°C in under five seconds, with a small form factor and rechargeable batteries, allowing for convenient and environmentally friendly operation.
Implementation Method 1
the inductor of the LC load network is inductively coupled to the susceptor of the aerosol-forming substrate during operation
Implementation Method 2
The induced alternating magnetic field generates heat in the susceptor
Implementation Method 3
The susceptor of the tobacco-laden substrate is exposed to an alternating magnetic field generated by an induction source, so that an alternating magnetic field is induced in the susceptor. This induced alternating magnetic field generates heat in the susceptor
Implementation Method 4
the power supply electronics comprising a DC/AC inverter connected to the DC power source, the DC/AC inverter including a Class-E power amplifier including a transistor switch and an LC load network configured to operate at low ohmic load
Implementation Method 5
the LC load network comprises a shunt capacitor and a series connection of a capacitor and an inductor
Implementation Method 6
the LC load network comprises a shunt capacitor and a series connection of a capacitor and an inductor having an ohmic resistance
Implementation Method 7
the Class-E power amplifier including a transistor switch and an LC load network configured to operate at low ohmic load
Data Source
AI summary
An inductive heating device (1) comprises: a device housing (10), a DC power source (11), a power supply electronics (13) comprising a DC/AC inverter (132) including a Class-E power amplifier with a transistor switch (1320), a transistor switch driver circuit (1322), and an LC load network (1323) configured to operate at low ohmic load (1324), the LC load network (1323) comprising a shunt capacitor (C1) and a series connection of a capacitor (C2) and an inductor (L2), and a cavity (14) arranged in the device housing (10), the cavity (14) having an internal surface shaped to accommodate at least a portion of the aerosol-forming substrate (20), wherein the cavity (14) is arranged such that the inductor (L2) is inductively coupled to the susceptor (21) of the aerosol-forming substrate (20) during operation.