Inductive Aerosol Heating with Probing Pulses for Temperature Control
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Solution Overview
Problem
Existing aerosol-generating systems with inductive heating devices face challenges in accurately monitoring and controlling the temperature of aerosol-forming substrates, particularly due to the lack of direct electrical connection between the susceptor and the inductive heating device, which limits precise temperature control and puff detection.
Innovation Solution
The implementation of a power supply electronics system that supplies power to the inductor in pulses, with probing pulses during intervals to monitor the susceptor's temperature indirectly by measuring current, allowing for fine control of heating cycles and temperature maintenance within a desired range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the susceptor is in direct contact with the aerosol-forming substrate for heat transfer, then heating efficiency is improved, but temperature monitoring precision deteriorates due to lack of direct electrical connection
Solution Approach 1:
The patent introduces an intermediary measurement approach by using the inductor as a sensing element. The inductor's electrical properties (inductance, resistance, or quality factor) change in response to temperature-induced changes in the susceptor's electrical properties, allowing indirect temperature measurement without direct electrical contact between the susceptor and control circuitry.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the inductor's electrical properties and using this information to adjust the heating power. The control circuitry modifies the heating parameters based on the measured temperature (inferred from electrical properties) to maintain the desired temperature range, creating a closed-loop control system.
2Temperature
If continuous heating is applied to maintain temperature, then temperature stability is improved, but energy consumption increases
Solution Approach 1:
The patent employs periodic pulsed heating instead of continuous heating. The control circuitry applies heating in discrete pulses with intervals between them, allowing the system to maintain temperature stability while reducing overall energy consumption. The pulse duration and frequency are adjusted based on the measured temperature and thermal requirements.
Solution Approach 2:
The patent implements dynamic control of heating parameters by continuously adjusting the pulse duration, frequency, and power level based on real-time temperature measurements (inferred from electrical properties). This dynamic adaptation allows the system to maintain temperature stability with minimal energy input by matching the heating rate to the actual thermal needs.
3Speed
If the inductor operates at high power for rapid heating, then heating speed is improved, but temperature control precision deteriorates
Solution Approach 1:
The patent uses periodic pulsed heating with varying duty cycles to achieve both rapid heating and precise control. During the heating phase, high power is applied for rapid temperature increase, while the intervals between pulses allow for cooling and measurement, enabling precise control of the heating process and preventing overheating.
Solution Approach 2:
The patent performs preliminary measurements of the inductor's electrical properties before and during heating pulses to predict temperature changes and adjust subsequent heating parameters accordingly. This preliminary action allows the system to prepare for temperature excursions and make corrective adjustments before excessive heating occurs.
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 improved temperature control and aerosol generation, allowing for efficient heating and precise monitoring of the aerosol-forming substrate, enhancing user experience and compatibility with substrates requiring narrow temperature ranges.
Implementation Method 1
The induction source generates an alternating electromagnetic field that induces eddy currents in the susceptor
Implementation Method 2
induces eddy currents in the susceptor. The induced eddy currents heat the susceptor through ohmic or resistive heating
Implementation Method 3
The induced eddy currents heat the susceptor through ohmic or resistive heating
Implementation Method 4
The susceptor is further heated as a result of hysteresis losses
Implementation Method 5
the susceptor is in direct contact with the aerosol-forming substrate and heat is transferred from the susceptor to the aerosol-forming substrate primarily by conduction
Data Source
Figure 1A~2B
Figure 3~5
Figure 6
AI summary
An inductive heating device (100), an aerosol-generating system and a method of operating an inductive heating device, wherein the inductive heating device (100) is configured to receive an aerosol-generating article (10) comprising an aerosol-forming substrate (20) and a susceptor (1,4), the inductive heating device (100) being configured to heat the susceptor (1,4) when the aerosol-generating article (10) is received by the inductive heating device (100). The inductive heating device (100) comprises: a DC power supply (150) for providing a DC supply voltage (VDC) and a current (IDC); power supply electronics (160) comprising a DC/AC converter (162) connected to the DC power supply (150); and an inductor (110) connected to the DC/AC converter(162)and arranged to inductively couple to the susceptor (1,4) of the aerosol-generating article(10) when the aerosol-generating article (10) is received by the inductive heating device (100). The power supply electronics (160) are configured to: supply power to the inductor (110) from the DC power supply (150), via the DC/AC converter (162), for heating the susceptor (1,4) of the aerosol-generating article (10) when the aerosol-generating article (10) is received by the inductive heating device (100), the supply of power being provided in a plurality of pulses separated by time intervals. The pulses comprise two or more heating pulses and one or more probing pulses between successive heating pulses. The power supply electronics (160) are further configured to control the duration of the time interval between successive heating pulses based on one or more measurements of the current supplied from the DC power supply (150) in one or more of the one or more probing pulses.