Aerosol generator and system equipped with induction heating device, and method of operation thereof.

Abstract

A method (800) for controlling aerosol generation in an aerosol generating apparatus (200) includes performing a calibration process (820) to measure a calibration value associated with the susceptor (160). The heating arrangement (320) is configured to inductively heat the susceptor (160) based on the calibration value. The calibration process includes i) controlling power provided to the heating arrangement (320) to increase a temperature of the susceptor (160), ii) monitoring a conductance or resistance value associated with the susceptor (160), iii) interrupting the provision of power to the heating arrangement (320) when the conductance value reaches a maximum value or the resistance value reaches a minimum value, and iv) monitoring the conductance value associated with the susceptor (160) until the conductance value reaches a minimum value or the resistance value reaches a maximum value.

Description

[Technical Field]

[0001] This disclosure relates to an induction heating device for heating an aerosol-forming substrate. The present invention further relates to an aerosol generator comprising such an induction heating device, and a method for controlling aerosol generation in an aerosol generator. [Background technology]

[0002] An aerosol generator may include an electrically operated heat source configured to heat an aerosol-forming substrate to generate an aerosol. The electrically operated heat source may be an induction heater. An induction heater typically includes an inductor configured to inductively couple to a susceptor. The inductor generates an alternating magnetic field that causes the susceptor to heat. Typically, 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. The temperature of the aerosol-forming substrate may be controlled by controlling the temperature of the susceptor. Therefore, for such aerosol generators, it is important to accurately monitor and control the temperature of the susceptor to ensure optimal aerosol generation and delivery to the user.

[0003] It is desirable to provide accurate, reliable, and inexpensive temperature monitoring and control for induction heating devices. [Overview of the Initiative]

[0004] According to one aspect of the present invention, a method for controlling aerosol generation in an aerosol generator is provided. The aerosol generator comprises a heating arrangement and a power supply for providing power to the heating arrangement. The method includes performing a calibration process to measure a calibration value associated with a susceptor, wherein the heating arrangement is configured to inductively heat the susceptor based on the calibration value. The calibration process includes: i) controlling the power supplied to the heating fixture to raise the temperature of the susceptor; ii) monitoring the conductance value or resistance value associated with the susceptor; iii) interrupting the supply of power to the heating fixture when the conductance value reaches a maximum value, or interrupting the supply of power to the heating fixture when the resistance value reaches a minimum value, wherein the conductance value at maximum conductance or the resistance value at minimum resistance is a second calibration value associated with the susceptor; and iv) monitoring the conductance value associated with the susceptor until the conductance value reaches a minimum value, or monitoring the resistance value associated with the susceptor until the resistance value reaches a maximum value, wherein the conductance value at minimum conductance or the resistance value at maximum resistance is a first calibration value associated with the susceptor.

[0005] The calibration process is fast and reliable without delaying aerosol generation. Furthermore, since the aerosol generator can be calibrated (or recalibrated) for two or more types of susceptors at any stage of the aerosol generator's lifecycle, the calibration process improves the flexibility and cost-effectiveness of the aerosol generator.

[0006] Preferably a susceptor, the susceptor may comprise a first material having a first Curie temperature and a second material having a second Curie temperature. The second calibration temperature of the susceptor associated with the second calibration conductance value may correspond to the second Curie temperature of the second material. Preferably the first and second materials are two separate materials bonded together and therefore in close physical contact with each other, thereby ensuring that both materials have the same temperature due to thermal conduction. Preferably the two materials are two layers or strips bonded along one of their main surfaces. The susceptor may further comprise a further third layer of material. Preferably the third layer of the susceptor material is made of the first susceptor material. Preferably the thickness of the third layer of the susceptor material is less than the thickness of the layer of the second susceptor material.

[0007] The calibration process may be performed during user operation of the aerosol generator. Performing calibration during user operation of the aerosol generator means that the calibration values ​​used to control the heating process are more accurate and reliable than if the calibration process were performed during manufacturing. This also improves flexibility and cost efficiency in that the aerosol generator can be calibrated for two or more types of susceptors. This is particularly important when the susceptor forms part of a separate aerosol generating article that does not form part of the aerosol generator. In such situations, calibration during manufacturing is not possible.

[0008] The method may further include controlling the power supplied to the induction heating arrangement to maintain the conductance value associated with the susceptor between a first calibration value and a second calibration value.

[0009] The induction heating arrangement may include a DC / AC converter and an inductor connected to the DC / AC converter. The susceptor may be arranged to be inductively coupled to the inductor. The conductance or resistance value is preferably determined based on the DC supply voltage of the power supply and the DC current drawn from the power supply. The DC current drawn from the power supply is preferably measured at the input side of the DC / AC converter. Furthermore, the DC supply voltage is preferably measured at the input side of the DC / AC converter. This is due to the fact that there is a monotonic relationship between the actual conductance of the susceptor (which cannot be determined if the susceptor does not form part of an aerosol generating article) and the apparent conductance thus determined (because the susceptor can impart conductance to the LCR circuit (of the DC / AC converter) to which it is coupled, since a large portion of the load (R) may be due to the resistance of the susceptor; the conductance is 1 / R. Therefore, references to the conductance of the susceptor are understood to refer to the apparent conductance when the susceptor forms part of a separate aerosol generating article).

[0010] Controlling the power supplied to the induction heating system may involve controlling the power supplied to the induction heating system to gradually increase the conductance value associated with the susceptor from a first operating conductance value to a second operating conductance value. The temperature of the susceptor associated with the first operating conductance value may be sufficient for the aerosol-forming substrate to form an aerosol.

[0011] The method may further include controlling the power supplied to the induction heating arrangement to maintain the resistance value associated with the susceptor between a first calibration value and a second calibration value. Controlling the power supplied to the induction heating arrangement may include controlling the power supplied to the induction heating arrangement to gradually decrease the resistance value associated with the susceptor from a first operating resistance value to a second operating resistance value. The temperature of the susceptor associated with the first operating resistance value may be sufficient for the aerosol-forming substrate to form an aerosol.

[0012] Performing the calibration process further includes: v) when the conductance value reaches a minimum value or the resistance value reaches a maximum value, controlling the power provided to the heating arrangement to increase the temperature of the susceptor; vi) monitoring the conductance value or resistance value associated with the susceptor; and vii) when the conductance value reaches a second maximum value or the resistance value reaches a second minimum value, interrupting the provision of power to the heating arrangement, where the conductance value at the second maximum value is a fourth calibration value associated with the susceptor or the resistance value at the second minimum value is a fourth calibration value associated with the susceptor, and interrupting; iv) monitoring the conductance value associated with the susceptor until the conductance value reaches a second minimum value, where the conductance value at the second minimum value is a third calibration value associated with the susceptor, or monitoring the resistance value associated with the susceptor until the resistance value reaches a second maximum value, where the resistance value at the second maximum value is a third calibration value associated with the susceptor.

[0013] The method may further include controlling the power provided to the induction heating arrangement to maintain the conductance value associated with the susceptor between a third calibration value and a fourth calibration value.

[0014] By repeating the steps of the calibration process and using the calibrated conductance values obtained during the repetition of the calibration process, subsequent temperature regulation is significantly improved because it takes more time for heat to disperse within the substrate.

[0015] Controlling the power provided to the induction heating arrangement may include controlling the power to the induction heating arrangement to gradually increase the conductance value associated with the susceptor from a first operating conductance value to a second operating conductance value.

[0016] By controlling the power supplied to the induction heating system, a gradual increase in susceptor temperature occurs, enabling the generation of aerosols with substantially constant delivery (nicotine, flavor, aerosol volume, etc.) for each puff throughout the user experience, over a sustained period encompassing several puffs, e.g., the entire user experience of 14 puffs, or a predetermined time interval such as 6 minutes. Specifically, the gradual increase in susceptor temperature prevents a reduction in aerosol delivery due to substrate depletion and a decrease in heat diffusion over time. Furthermore, the gradual temperature increase allows heat to diffuse into the substrate at each stage.

[0017] The method may further include controlling the power supplied to the induction heating arrangement to maintain the resistance value associated with the susceptor between a third and a fourth calibration value. Controlling the power supplied to the induction heating arrangement may include controlling the power supplied to the induction heating arrangement to gradually decrease the resistance value associated with the susceptor from a first operating resistance value to a second operating resistance value.

[0018] The aerosol generator may be configured to removably receive an aerosol generating article. The aerosol generating article may include a susceptor and an aerosol-forming substrate. The calibration process may be performed in response to the detection of the aerosol generating article.

[0019] The calibration process may be performed in response to the detection of user input.

[0020] The calibration process may be performed in response to the detection of a control signal associated with the completion of the preheating process. The preheating process may have a predetermined duration.

[0021] The method may further include performing a preheating process. The preheating process may include i) controlling the power supplied to the induction heating arrangement to raise the temperature of the susceptor; ii) monitoring the conductance or resistance value associated with the susceptor; and iii) interrupting the supply of power to the induction heating arrangement when the conductance value reaches a minimum or the resistance value reaches a maximum.

[0022] The preheating process allows heat to dissipate within the substrate before the calibration process is initiated, thereby further improving the reliability of the calibration values.

[0023] If the conductance value reaches its minimum or the resistance value reaches its maximum before the end of the predetermined duration of the preheating process, steps i) to iii) of the preheating process may be repeated until the end of the predetermined duration of the preheating process.

[0024] The predetermined duration allows heat to dissipate in a timely manner within the substrate, regardless of its physical state (e.g., whether it is dry or wet), to reach the minimum calibration value measured during the calibration process. This ensures the reliability of the calibration process.

[0025] If the conductance value does not reach the minimum value or the resistance value does not reach the maximum value during a predetermined duration of the preheating process, a control signal may be generated to stop the operation of the aerosol generator.

[0026] The susceptor is preferably provided within an aerosol generating article configured to be inserted into an aerosol generator. An aerosol generating article not configured for use with an aerosol generator will not behave in the same way as a genuine aerosol generating article. Specifically, the conductance associated with the susceptor will not reach a minimum value during a predetermined duration of the preheating process. This thus prevents the use of an unauthorized aerosol generating article.

[0027] The aerosol generator may be configured to receive an aerosol generating article. The aerosol generating article may include a susceptor and an aerosol-forming substrate. A preheating process may be performed in response to the detection of the aerosol generating article.

[0028] The preheating process may be performed in response to detection of user input.

[0029] According to another aspect of the present invention, an aerosol generator is provided. The aerosol generator comprises a power supply for providing a DC supply voltage and a DC current, and a power supply electronic circuit connected to the power supply. The power supply electronic circuit includes a DC / AC converter and an inductor connected to the DC / AC converter to generate an alternating magnetic field when energized by the alternating current from the DC / AC converter, the inductor being coupled to a susceptor. The susceptor is configured to heat an aerosol-forming substrate. The power supply electronic circuit further includes a controller. The controller is configured to perform a calibration process to measure a calibration value associated with the susceptor. The power supply electronic circuit is configured to inductively heat the susceptor based on the calibration value. The calibration process includes i) controlling the power supplied to the inductor to raise the temperature of the susceptor; ii) monitoring the conductance or resistance value associated with the susceptor; iii) interrupting the supply of power to the inductor when the conductance value reaches a maximum value, or interrupting the supply of power to the inductor when the resistance value reaches a minimum value, wherein the conductance value at the maximum conductance value, or the resistance value at the minimum resistance, is a second calibration value associated with the susceptor; and iv) monitoring the conductance value associated with the susceptor until the conductance value reaches a minimum value, or monitoring the resistance value associated with the susceptor until the resistance value reaches a minimum value, wherein the conductance value at the minimum conductance value, or the resistance value at the maximum resistance, is a first calibration value associated with the susceptor.

[0030] The second operating temperature of the susceptor associated with the second calibration conductance value may correspond to the Curie temperature of the susceptor material.

[0031] The calibration process may be performed during user operation of the aerosol generator.

[0032] The controller may also be configured to control the power supplied to the inductor to maintain the conductance value associated with the susceptor between a first calibration value and a second calibration value.

[0033] Controlling the power supplied to the inductor may involve controlling the power supplied to the inductor to gradually increase the conductance value associated with the susceptor from a first operating conductance value to a second operating conductance value. The temperature of the susceptor associated with the first operating conductance value may be sufficient for the aerosol-forming substrate to form an aerosol.

[0034] The controller may further be configured to control the power supplied to the induction heating arrangement to maintain the resistance value associated with the susceptor between a first calibration value and a second calibration value. Controlling the power supplied to the induction heating arrangement may include controlling the power supplied to the induction heating arrangement to gradually decrease the resistance value associated with the susceptor from a first operating resistance value to a second operating resistance value, such that the temperature of the susceptor associated with the first operating resistance value is sufficient for the aerosol-forming substrate to form an aerosol.

[0035] Performing a calibration process may further include: v) controlling the power supplied to the heating arrangement to raise the temperature of the susceptor when the conductance value reaches a minimum or the resistance value reaches a maximum; vi) monitoring the conductance or resistance value associated with the susceptor; vii) interrupting the supply of power to the inductor when the conductance value reaches a second maximum or the resistance value reaches a second minimum, wherein the conductance value at the second maximum is a fourth calibration value associated with the susceptor, or the resistance value at the second minimum is a fourth calibration value associated with the susceptor; vi) monitoring the conductance value associated with the susceptor until the conductance value reaches a second minimum, wherein the conductance value at the second minimum is a third calibration value associated with the susceptor, or monitoring the resistance value associated with the susceptor until the resistance value reaches a second maximum, wherein the resistance value at the second maximum is a third calibration value associated with the susceptor.

[0036] The controller may also be configured to control the power supplied to the inductor to maintain the conductance value associated with the susceptor between a third calibrated conductance value and a fourth calibrated conductance value.

[0037] Controlling the power supplied to the inductor may involve controlling the power to the inductor to gradually increase the conductance value associated with the susceptor from a first operating conductance value to a second operating conductance value.

[0038] The controller may also be configured to control the power supplied to the induction heating arrangement to maintain the resistance value associated with the susceptor between a third and a fourth calibration value.

[0039] Controlling the power supplied to the induction heating system may include controlling the power supplied to the induction heating system to gradually reduce the resistance value associated with the susceptor from a first operating resistance value to a second operating resistance value. The controller may be configured to perform a calibration process in response to the detection of an aerosol generating article containing a susceptor.

[0040] The controller may be configured to perform a calibration process in response to detecting user input.

[0041] The controller may be configured to perform a calibration process in response to detecting a control signal associated with the end of the preheating process, the preheating process having a predetermined duration.

[0042] The controller may further be configured to perform a preheating process. The preheating process may include: i) controlling the power supplied to the inductor to raise the temperature of the susceptor; ii) monitoring the conductance or resistance value associated with the susceptor; and iii) interrupting the supply of power to the inductor when the conductance value reaches a minimum or the resistance value reaches a maximum.

[0043] The controller may be configured to repeat steps i) to iii) of the preheating process until the end of the predetermined duration of the preheating process if the conductance value reaches a minimum value or the resistance value reaches a maximum value before the end of the predetermined duration of the preheating process.

[0044] The controller may be configured to generate a control signal to stop the operation of the aerosol generator if the conductance value of the susceptor does not reach the minimum value or the resistance value does not reach the maximum value during a predetermined duration of the preheating process.

[0045] The controller may be configured to perform a preheating process in response to the detection of an aerosol-generating article, including a susceptor.

[0046] The controller may be configured to perform a preheating process in response to detecting user input.

[0047] The aerosol generator may further include a housing having a cavity configured to receive an aerosol generating article. The aerosol generating article may include an aerosol-forming substrate and a susceptor.

[0048] According to another aspect of the present invention, an aerosol generating system is provided. The aerosol generating system comprises the above-described aerosol generating device and an aerosol generating article. The aerosol generating article includes an aerosol forming substrate and a susceptor.

[0049] The susceptor may include a first susceptor material and a second susceptor material, the first susceptor material being positioned in physical contact with the second susceptor material. The first susceptor material may have a first Curie temperature, and the second susceptor material may have a second Curie temperature. The second Curie temperature may be lower than the first Curie temperature. The second calibration temperature may correspond to the Curie temperature of the second susceptor material.

[0050] As used herein, the term “aerosol generator” refers to a device that generates an aerosol by interacting with an aerosol-forming substrate. An aerosol generator may interact with either or both an aerosol-generating article containing an aerosol-forming substrate and / or a cartridge containing an aerosol-forming substrate. In some embodiments, the aerosol generator may heat the aerosol-forming substrate to facilitate the release of volatile compounds from the substrate. An electrically operated aerosol generator may include an atomizer, such as an electric heater, for heating the aerosol-forming substrate to form an aerosol.

[0051] As used herein, the term "aerosol generating system" refers to a combination of an aerosol-forming substrate and an aerosol generating device. When the aerosol-forming substrate forms part of an aerosol-generating article, the aerosol generating system refers to a combination of an aerosol-generating article and an aerosol generating device. In an aerosol generating system, the aerosol-forming substrate and the aerosol generating device work together to generate an aerosol.

[0052] As used herein, the term “aerosol-forming substrate” refers to a substrate having the ability to release volatile compounds that can form aerosols. Volatile compounds may be released by heating or burning the aerosol-forming substrate. As an alternative to heating or burning, in some cases, volatile compounds may be released by chemical reactions or by mechanical stimuli such as ultrasound. The aerosol-forming substrate may be solid or may contain both solid and liquid components. The aerosol-forming substrate may be part of an aerosol-generating article.

[0053] As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate having the ability to release volatile compounds capable of forming aerosols. Aerosol-generating articles may be disposable. Aerosol-generating articles comprising an aerosol-forming substrate containing tobacco may be referred to herein as tobacco sticks.

[0054] The aerosol-forming substrate may contain nicotine. The aerosol-forming substrate may contain tobacco, and may also contain a tobacco-containing material that contains volatile tobacco-flavored compounds released from the aerosol-forming substrate upon heating. In a preferred embodiment, the aerosol-forming substrate may contain homogenized tobacco material, such as cast-leaf tobacco. The aerosol-forming substrate may contain both solid and liquid components. The aerosol-forming substrate may contain a tobacco-containing material that contains volatile tobacco-flavored compounds released from the substrate upon heating. The aerosol-forming substrate may contain non-tobacco materials. The aerosol-forming substrate may further contain aerosol-forming bodies. Examples of suitable aerosol-forming bodies are glycerin and propylene glycol.

[0055] As used herein, “aerosol cooling element” refers to a component of an aerosol generating article positioned downstream of an aerosol generating substrate such that, during use, aerosols formed by volatile compounds released from the aerosol generating substrate pass through the aerosol cooling element and are cooled by the aerosol cooling element before being inhaled by the user. Aerosol cooling elements have a large surface area but produce a low pressure drop. Filters and other mouthpieces that produce a high pressure drop (e.g., filters formed from bundles of fibers) are not considered aerosol cooling elements. Chambers and cavities within an aerosol generating article are not considered aerosol cooling elements.

[0056] As used herein, the term “mouthpiece” refers to a part of an aerosol generating article, aerosol generating device, or aerosol generating system that is placed in the user’s mouth for direct inhalation of an aerosol.

[0057] As used herein, the term “susceptor” refers to an element containing a material capable of converting magnetic field energy into heat. When a susceptor is placed in an alternating magnetic field, it heats up. The heating of the susceptor may result from at least one of hysteresis losses and eddy currents induced within the susceptor, depending on the electrical properties and magnetism of the susceptor material.

[0058] As used herein in reference to an aerosol generator, the terms “upstream” and “forward,” as well as “downstream” and “backward,” are used to describe the relative position of a component or part of a component of the aerosol generator with respect to the direction in which air flows through the aerosol generator during use. The aerosol generator according to the present invention has a proximal end through which aerosols exit the device during use. The proximal end of the aerosol generator may also be called the mouth end or downstream end. The mouth end is downstream of the distal end. The distal end of the aerosol generating article may also be called the upstream end. Components or parts of components of an aerosol generator may be described as being upstream or downstream of each other based on their relative positions with respect to the airflow path of the aerosol generator.

[0059] The terms “upstream” and “forward,” and “downstream” and “backward,” as used herein when referring to an aerosol-generating article, are used to describe the relative position of a component or part of a component of the aerosol-generating article with respect to the direction in which air flows through the aerosol-generating article during its use. The aerosol-generating article according to the present invention includes a proximal end through which an aerosol exits the article during use. The proximal end of an aerosol-generating article may also be called the mouth end or downstream end. The mouth end is downstream of the distal end. The distal end of an aerosol-generating article may also be called the upstream end. A component or part of a component of an aerosol-generating article may be described as being upstream or downstream of each other based on their relative positions between the proximal end and the distal end of the aerosol-generating article. The forward end of a component or part of a component of an aerosol-generating article is the part closest to the upstream end of the aerosol-generating article. The backward end of a component or part of a component of an aerosol-generating article is the part closest to the downstream end of the aerosol-generating article.

[0060] As used herein, the term “inductive coupling” refers to the heating of a susceptor when it is penetrated by an alternating magnetic field. Heating may be caused by the generation of eddy currents within the susceptor. Heating may also be caused by magnetic hysteresis losses.

[0061] As used herein, the term “inhaling” means the action of drawing an aerosol into the body through one’s mouth or nose.

[0062] The present invention is defined in the claims. However, a non-exclusive list of non-limiting embodiments is provided below. One or more features of these embodiments may be combined with one or more features of other embodiments, forms, or aspects described herein.

[0063] Example 1: A method for controlling aerosol generation in an aerosol generator, the aerosol generator comprising a heating element and a power supply for providing power to the heating element, the method comprising performing a calibration process to measure a calibration value associated with a susceptor, the heating element being configured to inductively heat the susceptor based on the calibration value, the calibration process comprising i) controlling the power supplied to the heating element to raise the temperature of the susceptor, ii) monitoring a conductance or resistance value associated with the susceptor, and iii) controlling the power supply to the heating element when the conductance value reaches its maximum value. A method comprising: iv) interrupting the supply of power to a heating arrangement when the resistance value reaches a minimum value, wherein the conductance value at the maximum conductance value or the resistance value at the minimum resistance is a second calibration value associated with the susceptor; and iv) monitoring the conductance value associated with the susceptor until the conductance value reaches a minimum value, or monitoring the resistance value associated with the susceptor until the resistance value reaches a maximum value, wherein the conductance value at the minimum conductance value or the resistance value at the maximum resistance is a first calibration value associated with the susceptor. Example 2: The susceptor comprises a first material having a first Curie temperature and a second material having a second Curie temperature, wherein the second Curie temperature is lower than the first Curie temperature, and the second calibration temperature of the susceptor associated with a second calibration conductance value corresponds to the second Curie temperature of the second material, according to Example 1. Example 3: The calibration process is performed during user operation of the aerosol generator, using the method according to Example 1 or 2. Example 4: A method according to any one of Examples 1 to 3, further comprising controlling the power supplied to the induction heating arrangement to maintain the conductance value associated with the susceptor between a first calibration value and a second calibration value. Example 5: Controlling the power supplied to the induction heating arrangement involves controlling the power supplied to the induction heating arrangement to gradually increase the conductance value associated with the susceptor from a first operating conductance value to a second operating conductance value, wherein the temperature of the susceptor associated with the first operating conductance value is sufficient for the aerosol-forming substrate to form an aerosol, as per Example 4. Example 6: A method according to any one of Examples 1 to 3, further comprising controlling the power supplied to the induction heating arrangement to maintain the resistance value associated with the susceptor between a first calibration value and a second calibration value. Example 7: Controlling the power supplied to the induction heating arrangement involves controlling the power supplied to the induction heating arrangement to gradually decrease the resistance value associated with the susceptor from a first operating resistance value to a second operating resistance value, wherein the temperature of the susceptor associated with the first operating resistance value is sufficient for the aerosol-forming substrate to form an aerosol, as per Example 6. Example 8: Performing the calibration process further involves v) controlling the power supplied to the heating arrangement to raise the temperature of the susceptor when the conductance value reaches a minimum or the resistance value reaches a maximum; vi) monitoring the conductance value or resistance value associated with the susceptor; and vii) interrupting the supply of power to the heating arrangement when the conductance value reaches a second maximum or the resistance value reaches a second minimum, wherein the conductance value at the second maximum is a fourth calibration value associated with the susceptor, or a second minimum A method according to any one of Examples 1 to 3, comprising: interrupting the process, iv) monitoring the conductance value associated with the susceptor until the conductance value reaches a second minimum value, the conductance value at the second minimum value being a third calibration value associated with the susceptor, or monitoring the resistance value associated with the susceptor until the resistance value reaches a second maximum value, the resistance value at the second maximum value being a third calibration value associated with the susceptor. Example 9: The method according to Example 8, further comprising controlling the power supplied to the induction heating arrangement to maintain the conductance value associated with the susceptor between a third calibration value and a fourth calibration value. Example 10: A method according to Example 9, wherein controlling the power supplied to an induction heating arrangement involves controlling the power to the induction heating arrangement to gradually increase the conductance value associated with the susceptor from a first operating conductance value to a second operating conductance value. Example 11: The method according to Example 8, further comprising controlling the power supplied to the induction heating arrangement to maintain the resistance value associated with the susceptor between a third calibration value and a fourth calibration value. Example 12: Controlling the power supplied to the induction heating arrangement is a method according to Example 11, comprising controlling the power supplied to the induction heating arrangement to gradually decrease the resistance value associated with the susceptor from a first operating resistance value to a second operating resistance value. Example 13: The aerosol generator is configured to removably receive an aerosol generating article, the aerosol generating article comprising a susceptor and an aerosol forming substrate, and the calibration process is carried out in response to the detection of the aerosol generating article, according to any of Examples 1 to 12. Example 14: The calibration process is performed in response to detecting user input, according to any of Examples 1 to 12. Example 15: The calibration process is performed in response to detecting a control signal associated with the end of the preheating process, and the preheating process has a predetermined duration, according to any of Examples 1 to 12. Example 16: The method according to Example 15, further comprising a preheating process, the preheating process comprising: i) controlling the power supplied to the induction heating arrangement to raise the temperature of the susceptor; ii) monitoring the conductance or resistance value associated with the susceptor; and iii) interrupting the supply of power to the induction heating arrangement when the conductance value reaches a minimum or the resistance value reaches a maximum. Example 17: The method according to Example 16, further comprising repeating steps i) to iii) of the preheating process until the end of the predetermined duration of the preheating process if the conductance value reaches a minimum value or the resistance value reaches a maximum value before the end of the predetermined duration of the preheating process. Example 18: The method according to Example 15 or 16, further comprising generating a control signal to stop the operation of the aerosol generator if the conductance value does not reach a minimum value or the resistance value does not reach a maximum value during a predetermined duration of the preheating process. Example 19: A method according to any of Examples 15-18, wherein the aerosol generator is configured to receive an aerosol generating article, the aerosol generating article comprising a susceptor and an aerosol forming substrate, and the preheating process is carried out in response to the detection of the aerosol generating article. Example 20: The preheating process is performed according to any of Examples 15-18, in response to detecting user input. Example 21: A power supply for providing a DC supply voltage and DC current, and a power supply electronic circuit connected to the power supply, comprising a DC / AC converter, an inductor connected to the DC / AC converter for generating an alternating magnetic field when energized by the alternating current from the DC / AC converter, and capable of being coupled to a susceptor, the susceptor being configured to heat an aerosol forming substrate, and a controller configured to perform a calibration process to measure a calibration value associated with the susceptor, wherein the power supply electronic circuit is configured to inductively heat the susceptor based on the calibration value, the calibration process comprising i) controlling the power supplied to the inductor to raise the temperature of the susceptor, and ii) the conductance associated with the susceptor an aerosol generator comprising: iii) a step of monitoring a value or resistance value; iii) a step of interrupting the supply of power to an inductor when the conductance value reaches a maximum value, or when the resistance value reaches a minimum value, wherein the conductance value at maximum conductance or the resistance value at minimum resistance is a second calibration value associated with the susceptor; and iv) a step of monitoring the conductance value associated with the susceptor until the conductance value reaches a minimum value, or until the resistance value associated with the susceptor reaches a maximum value, wherein the conductance value at minimum conductance or the resistance value at maximum resistance is a first calibration conductance value associated with the susceptor. Example 22: An aerosol generator according to Example 21, wherein the second operating temperature of the susceptor associated with the second calibration conductance value corresponds to the Curie temperature of the susceptor material. Example 23: An aerosol generator according to Example 21 or 22, in which the calibration process is performed during user operation of the aerosol generator. Example 24: An aerosol generator according to any of Examples 21-23, wherein the controller is further configured to control the power supplied to the inductor to maintain the conductance value associated with the susceptor between a first calibration value and a second calibration value. Example 25: An aerosol generator according to Example 24, wherein controlling the power supplied to the inductor involves controlling the power supplied to the inductor to gradually increase the conductance value associated with the susceptor from a first operating conductance value to a second operating conductance value, wherein the temperature of the susceptor associated with the first operating conductance value is sufficient for the aerosol-forming substrate to form an aerosol. Example 26: An aerosol generator according to any of Examples 21-23, wherein the controller is further configured to control the power supplied to the induction heating arrangement to maintain the resistance value associated with the susceptor between a first calibration value and a second calibration value. Example 27: Controlling the power supplied to the induction heating arrangement involves controlling the power supplied to the induction heating arrangement to gradually decrease the resistance value associated with the susceptor from a first operating resistance value to a second operating resistance value, wherein the temperature of the susceptor associated with the first operating resistance value is sufficient for the aerosol-forming substrate to form an aerosol, in the aerosol generator according to Example 26. Example 28: The calibration process further comprises v) controlling the power supplied to the heating device to raise the temperature of the susceptor when the conductance value reaches a minimum or the resistance value reaches a maximum; vi) monitoring the conductance value or resistance value associated with the susceptor; and vii) interrupting the supply of power to the inductor when the conductance value reaches a second maximum or the resistance value reaches a second minimum, wherein the conductance value at the second maximum is a fourth calibration value associated with the susceptor, or at the second minimum... an aerosol generator according to any of Examples 21 to 23, comprising: interrupting the process, where the resistance value is a fourth calibration value associated with the susceptor; monitoring the conductance value associated with the susceptor until the conductance value reaches a second minimum value, where the conductance value at the second minimum value is a third calibration value associated with the susceptor; or monitoring the resistance value associated with the susceptor until the resistance value reaches a second maximum value, where the resistance value at the second maximum value is a third calibration value associated with the susceptor. Example 29: An aerosol generator according to Example 28, wherein the controller is further configured to control the power supplied to the inductor to maintain the conductance value associated with the susceptor between a third and a fourth calibration value. Example 30: An aerosol generator according to Example 29, wherein controlling the power supplied to the inductor involves controlling the power to the inductor to gradually increase the conductance value associated with the susceptor from a first operating conductance value to a second operating conductance value. Example 31: Controller The aerosol generator according to Example 28, further configured to control the power supplied to the induction heating arrangement to maintain the resistance value associated with the susceptor between a third and a fourth calibration value. Example 32: Controlling the power supplied to the induction heating arrangement, an aerosol generator according to Example 29, comprising controlling the power supplied to the induction heating arrangement to gradually decrease the resistance value associated with the susceptor from a first operating resistance value to a second operating resistance value. Example 33: An aerosol generator according to any of Examples 21 to 32, wherein the controller is configured to perform a calibration process in response to the detection of an aerosol-generating article containing a susceptor. Example 34: An aerosol generator according to any of Examples 21-32, wherein the controller is configured to perform a calibration process in response to detecting user input. Example 35: An aerosol generator according to any of Examples 21-32, wherein the controller is configured to perform a calibration process in response to detecting a control signal associated with the end of the preheating process, and the preheating process has a predetermined duration. Example 36: The aerosol generator according to Example 35, wherein the controller is further configured to perform a preheating process, the preheating process comprising: i) controlling the power supplied to the inductor to raise the temperature of the susceptor; ii) monitoring the conductance or resistance value associated with the susceptor; and iii) interrupting the supply of power to the inductor when the conductance value reaches a minimum or the resistance value reaches a maximum. Example 37: An aerosol generator according to Example 36, wherein the controller is configured to repeat steps i) to iii) of the preheating process until the end of the predetermined duration of the preheating process if the conductance value reaches a minimum value or the resistance value reaches a maximum value before the end of the predetermined duration of the preheating process. Example 38: An aerosol generator according to Example 36 or 37, wherein the controller is configured to generate a control signal to stop the operation of the aerosol generator if the conductance value of the susceptor does not reach a minimum value or the resistance value does not reach a maximum value during a predetermined duration of the preheating process. Example 39: An aerosol generator according to any of Examples 35-38, wherein the controller is configured to perform a preheating process in response to the detection of an aerosol-generating article containing a susceptor. Example 40: An aerosol generator according to any of Examples 35-39, wherein the controller is configured to perform a preheating process in response to detecting user input. Example 41: An aerosol generator according to any of Examples 21 to 40, further comprising a housing having a cavity configured to receive an aerosol generating article, wherein the aerosol generating article includes an aerosol forming substrate and a susceptor. Example 42: An aerosol generating system comprising an aerosol generating device according to any one of claims 21 to 41 and an aerosol generating article, wherein the aerosol generating article includes an aerosol forming substrate and a susceptor. Example 43: An aerosol generating system according to Example 42, wherein the susceptor comprises a first susceptor material and a second susceptor material, the first susceptor material being positioned in physical contact with the second susceptor material. Example 44: An aerosol generation system according to Example 42 or 43, wherein the first susceptor material has a first Curie temperature, and the second susceptor material has a second Curie temperature, the second Curie temperature being lower than the first Curie temperature. Example 45: An aerosol generation system according to Example 44, wherein the second calibration temperature corresponds to the Curie temperature of the second susceptor material.

[0064] Here, we will further describe the embodiments with reference to the figures. [Brief explanation of the drawing]

[0065] [Figure 1] Figure 1 shows a schematic cross-sectional view of an aerosol-generating object. [Figure 2] Figure 2A shows a schematic cross-sectional view of an aerosol generator for use with the aerosol generating article shown in Figure 1. Figure 2B shows a schematic cross-sectional view of an aerosol generator engaged with the aerosol generating article shown in Figure 1. [Figure 3] Figure 3 is a block diagram showing the induction heating device of the aerosol generator described in relation to Figure 2. [Figure 4] Figure 4 is a schematic diagram showing the electronic components of the induction heating device described in relation to Figure 3. [Figure 5] Figure 5 is a schematic diagram of the inductor in the LC load network of the induction heating device described in relation to Figure 4. [Figure 6] Figure 6 is a DC current-to-time graph showing the remotely detectable change in current that occurs when a susceptor material undergoes a phase transition related to its Curie point. [Figure 7] Figure 7 shows the temperature profile of the susceptor during operation of the aerosol generator. [Figure 8] Figure 8 is a flowchart illustrating a method for controlling aerosol generation in the aerosol generator shown in Figure 2. [Modes for carrying out the invention]

[0066] Figure 1 shows an aerosol generating article 100. The aerosol generating article 100 comprises four elements arranged coaxially: an aerosol forming substrate 110, a support element 120, an aerosol cooling element 130, and a mouthpiece 140. Each of these four elements is substantially cylindrical and has substantially the same diameter. These four elements are arranged in a continuous manner and surrounded by an outer wrapper 150 to form a cylindrical rod. An elongated susceptor 160 is positioned inside the aerosol forming substrate 110, in contact with the aerosol forming substrate 110. The susceptor 160 has approximately the same length as the aerosol forming substrate 110 and is positioned along the radial central axis of the aerosol forming substrate 110.

[0067] The susceptor 160 comprises at least two different materials. The susceptor 160 is preferably in the form of an elongated strip having a length of 12 mm and a width of 4 mm. The susceptor 160 comprises at least two layers, wherein the first layer of the first susceptor material is positioned in physical contact with the second layer of the second susceptor material. The first and second susceptor materials may each have a Curie temperature. In this case, the Curie temperature of the second susceptor material is lower than that of the first susceptor material. The first material may not have a Curie temperature. The first susceptor material may be aluminum, iron, or stainless steel. The second susceptor material may be nickel or a nickel alloy. The susceptor 160 may be formed by electroplating at least one patch of the second susceptor material onto a strip of the first susceptor material. The susceptor may be formed by cladding a fragment of a second susceptor material to a fragment of a first susceptor material.

[0068] The aerosol generating article 100 has a proximal end or oral end 170 that the user inserts into their mouth during use, and a distal end 180 that is located at the end opposite to the oral end 170 of the aerosol generating article 100. When assembled, the total length of the aerosol generating article 100 is preferably about 45 mm and the diameter is preferably about 7.2 mm.

[0069] In use, air is drawn by the user through the aerosol generating article 100 from the distal end 180 to the mouth end 170. The distal end 180 of the aerosol generating article 100 may also be described as the upstream end of the aerosol generating article 100, and the mouth end 170 of the aerosol generating article 100 may also be described as the downstream end of the aerosol generating article 100. An element of the aerosol generating article 100 located between the mouth end 170 and the distal end 180 may be described as being upstream of the mouth end 170 or downstream of the distal end 180. The aerosol forming substrate 110 is located at the distal end or the upstream end 180 of the aerosol generating article 100.

[0070] The support element 120 is positioned immediately downstream of the aerosol-forming substrate 110, in contact with the aerosol-forming substrate 110. The support element 120 may be a hollow cellulose acetate tube. The support element 120 causes the aerosol-forming substrate 110 to be positioned at the most distal end 180 of the aerosol-generating article 100. The support element 120 also acts as a spacer for the aerosol cooling element 130 of the aerosol-generating article 100 to pass through the gap from the aerosol-forming substrate 110.

[0071] The aerosol cooling element 130 is positioned immediately downstream of the support element 120, in contact with the support element 120. During use, volatile substances released from the aerosol-forming substrate 110 pass along the aerosol cooling element 130 toward the mouth end 170 of the aerosol-generating article 100. The volatile substances may cool within the aerosol cooling element 130 to form an aerosol that is inhaled by the user. The aerosol cooling element 130 may include an assembly of crimped sheets of polylactic acid surrounded by a wrapper 190. The assembly of crimped sheets of polylactic acid defines a plurality of longitudinal channels extending along the length of the aerosol cooling element 130.

[0072] The mouthpiece 140 is positioned immediately downstream of the aerosol cooling element 130, in contact with the aerosol cooling element 130. The mouthpiece 140 contains a conventional cellulose acetate tow filter with low filtration efficiency.

[0073] To assemble the aerosol-generating article 100, the four elements 110, 120, 130, and 140 described above are aligned and tightly rolled within the outer wrapper 150. The outer wrapper may be conventional cigarette paper. The susceptor 160 may be inserted into the aerosol-forming substrate 110 during the process used to form the aerosol-forming substrate 110, before the multiple elements are assembled to form a rod.

[0074] The aerosol generating article 100 shown in Figure 1 is designed to engage with an aerosol generating device, such as the aerosol generating device 200 shown in Figure 2A, for generating an aerosol. The aerosol generating device 200 comprises a housing 210 having a cavity 220 configured to receive the aerosol generating article 100. The aerosol generating device 200 further comprises an induction heating device 230 configured to heat the aerosol generating article 100 in order to generate an aerosol. Figure 2B shows the aerosol generating device 200 with the aerosol generating article 100 inserted into the cavity 220.

[0075] The induction heating device 230 is shown as a block diagram in Figure 3. The induction heating device 230 includes a DC power supply 310 and a heating arrangement 320 (also referred to as the power supply electronic circuit). The heating arrangement includes a controller 330, a DC / AC converter 340, a matching network 350, and an inductor 240.

[0076] The DC power supply 310 is configured to supply DC power to the heating equipment 320. Specifically, the DC power supply 310 has a DC supply voltage (V DC ) and DC current (I DC The power supply 310 is configured to supply power to the DC / AC converter 340. The power supply 310 is preferably a battery, such as a lithium-ion battery. Alternatively, the power supply 310 may be another form of charge storage device, such as a capacitor. The power supply 310 may require recharging. For example, the power supply 310 may have sufficient capacity to enable continuous generation of aerosol for approximately six minutes, or for periods that are multiples of six minutes. In another example, the power supply 310 may have sufficient capacity to enable a predetermined number of fume extractions or discontinuous starts of a heating arrangement.

[0077] The DC / AC converter 340 is configured to supply a high-frequency alternating current to the inductor 240. As used herein, the term “high-frequency alternating current” means an alternating current having a frequency of about 500 kilohertz to about 30 megahertz. The high-frequency alternating current may have a frequency of about 1 megahertz to about 30 megahertz (e.g., about 1 megahertz to about 10 megahertz, or about 5 megahertz to about 8 megahertz).

[0078] Figure 4 schematically shows the electronic components of the induction heating device 230, in particular the DC / AC converter 340. The DC / AC converter 340 may include a Class E power amplifier. The Class E power amplifier includes, for example, a transswitch 410 containing a field-effect transistor 420 which is a metal-oxide-semiconductor field-effect transistor, a transistor switch supply circuit for supplying a switching signal (gate-source voltage) to the field-effect transistor 420, indicated by arrow 430, and an LC load network 440 including a shunt capacitor C1 and a series connection of capacitor C2 and inductor L2 corresponding to inductor 240. Furthermore, the DC power supply 310, including a choke L1, supplies a DC supply voltage V DC It is indicated to supply DC current I DC The ohm resistance R of inductor L2 is drawn from DC power supply 310 during operation. coil and the ohm resistance R of the susceptor 160 load The ohm resistance R, which represents the total ohm load of 450 (the sum of the two values), is shown in detail in Figure 5.

[0079] Although the DC / AC converter 340 is shown as including a Class E power amplifier, it is naturally possible to use any suitable circuit for converting DC current to AC current. For example, the DC / AC converter 340 may include a Class D power amplifier including two transistor switches. As another example, the DC / AC converter 340 may include a full-bridge power inverter in which four switching transistors work in pairs.

[0080] Returning to Figure 3, the inductor 240 may receive AC current from the DC / AC converter 340 via a matching network 350 to best suit the load, although the matching network 350 is not mandatory. The matching network 350 may include a small matching transformer. The matching network 350 can improve the power transfer efficiency between the DC / AC converter 340 and the inductor 240.

[0081] As shown in Figure 2A, the inductor 240 is positioned adjacent to the distal portion 225 of the cavity 220 of the aerosol generator 200. Therefore, the high-frequency alternating current supplied to the inductor 240 during the operation of the aerosol generator 200 causes the inductor 240 to generate a high-frequency alternating magnetic field within the distal portion 225 of the aerosol generator 200. The alternating magnetic field preferably has a frequency of 1 to 30 megahertz, preferably 2 to 10 megahertz, for example, 5 to 7 megahertz. As can be seen from Figure 2B, when the aerosol generating article 100 is inserted into the cavity 200, the aerosol forming substrate 110 of the aerosol generating article 100 is positioned adjacent to the inductor 240 so that the susceptor 160 of the aerosol generating article 100 is positioned within this alternating magnetic field. When the alternating magnetic field penetrates the susceptor 160, the susceptor 160 is heated by the alternating magnetic field. For example, eddy currents are generated within the susceptor 160 as a result of heating. Further heating is provided by magnetic hysteresis loss within the susceptor 160. The heated susceptor 160 heats the aerosol-forming substrate 110 of the aerosol-generating article 100 to a temperature sufficient to form an aerosol. The aerosol is drawn downstream through the aerosol-generating article 100 and inhaled by the user.

[0082] The controller 330 may be a microcontroller, preferably a programmable microcontroller. The controller 330 is programmed to regulate the power supply from the DC power supply 310 to the induction heating arrangement 320 in order to control the temperature of the susceptor 160.

[0083] FIG. 6 shows the DC current I drawn from the power supply 310 over time as the temperature of the susceptor 160 (indicated by the dotted line) increases. DC The DC current I drawn from the power supply 310 DC is measured on the input side of the DC / AC converter 340. For the purposes of this figure, it can be assumed that the voltage V of the power supply 310 DC is substantially constant. As the susceptor 160 is inductively heated, the apparent resistance of the susceptor 160 increases. This increase in resistance is observed as a decrease in the DC current I drawn from the power supply 310 that decreases as the temperature of the susceptor 160 increases at a constant voltage. The high-frequency alternating magnetic field provided by the inductor 240 induces eddy currents, an effect known as the skin effect, in the vicinity of the susceptor surface. The resistance of the susceptor 160 depends in part on the electrical resistance of the first susceptor material and the resistance of the second susceptor material, and the resistance of the second susceptor material depends in part on the depth of the skin layer in each material available for the induced overcurrent, and then the resistance depends on the temperature. When the second susceptor material reaches its Curie temperature, its magnetism is lost. As a result, the skin layer available for eddy currents in the second susceptor material increases, thereby reducing the apparent resistance of the susceptor 160. As a result, when the skin depth of the second susceptor material begins to increase, the detected DC current I DC The resistance of the susceptor 160 depends in part on the electrical resistance of the first susceptor material and the resistance of the second susceptor material, and the resistance of the second susceptor material depends in part on the depth of the skin layer in each material available for the induced overcurrent, and then the resistance depends on the temperature. When the second susceptor material reaches its Curie temperature, its magnetism is lost. As a result, the skin layer available for eddy currents in the second susceptor material increases, thereby reducing the apparent resistance of the susceptor 160. As a result, when the skin depth of the second susceptor material begins to increase, the detected DC current I DCThe current temporarily increases, and the resistance begins to decrease. This can be seen as a trough (local minimum) in Figure 6. The current continues to increase until it reaches the maximum skin depth, which coincides with the point at which the second susceptor material loses its spontaneous magnetism. This point is called the Curie temperature and can be seen as a peak (local maximum) in Figure 6. At this point, the second susceptor material undergoes a phase change from a ferromagnetic or ferrimagnetic state to a paramagnetic state. At this point, susceptor 160 is at a known temperature (the Curie temperature, which is the intrinsic temperature of the material). After reaching the Curie temperature, if the inductor 240 continues to generate an alternating magnetic field (i.e., power to the DC / AC converter 340 is not interrupted), eddy currents generated within the susceptor 160 flow against the resistance of the susceptor 160, sustaining Joule heating within the susceptor 160. This causes the resistance to increase again (the resistance may have a polynomial dependence with respect to temperature, which for most metal susceptor materials can be approximated for our purposes as a cubic polynomial dependence), and the current begins to decrease again as long as the inductor 240 continues to supply power to the susceptor 160.

[0084] Therefore, as can be seen from Figure 6, the susceptor 160 (and the corresponding current I drawn from the power supply 310) DC The apparent resistance of the susceptor 160 can change with the temperature of the susceptor 160 in a strictly monotonic relationship over a specific temperature range of the susceptor 160. This strictly monotonic relationship makes it possible to clearly determine the temperature of the susceptor 160 from the determination of the apparent resistance or apparent conductance (1 / R). This is because each determined value of the apparent resistance represents only a single value of temperature, and there is no ambiguity in the relationship. The monotonic relationship between the temperature of the susceptor 160 and the apparent resistance enables the determination and control of the temperature of the susceptor 160, and therefore the determination and control of the temperature of the aerosol-forming substrate 110. The apparent resistance of the susceptor 160 is determined by the DC current I drawn from at least the DC power supply 310. DC It can be detected remotely by monitoring.

[0085] At least the DC current I drawn from power supply 310 DCThis is monitored by the controller 330. Preferably, the DC current I drawn from the power supply 310 is monitored. DC and DC supply voltage V DC Both are monitored. The controller 330 adjusts the power supply provided to the heating arrangement 320 based on the conductance value or resistance value, and conductance is the DC current I DC and DC supply voltage V DC The resistance is defined as the ratio of the DC supply voltage V. DC and DC current I D It is defined as the ratio of . The heating equipment 320 uses DC current I DC It may include a current sensor (not shown) for measuring the current. Heating arrangement is optional, DC supply voltage V DC It may include a voltage sensor (not shown) for measuring the current. The current sensor and voltage sensor are located on the input side of the DC / AC converter 340. DC current I DC and optionally DC supply voltage V DC This is provided by a feedback channel to the controller 330, and AC power P is supplied to the inductor 240. AC Control the further supply of [the product / service].

[0086] The controller 330 can control the temperature of the susceptor 160 by maintaining the measured conductance value or measured resistance value at a target value corresponding to the target operating temperature of the susceptor 160. The controller 330 can maintain the measured conductance value or measured resistance value at a target value using any suitable control loop, for example, by using a proportional-integral-differential control loop.

[0087] To utilize the strictly monotonic relationship between the apparent resistance (or apparent conductance) of the susceptor 160 and the temperature of the susceptor 160, during user operation to generate aerosols, the conductance or resistance value associated with the susceptor and measured at the input side of the DC / AC converter 340 is maintained between a first calibration value corresponding to a first calibration temperature and a second calibration value corresponding to a second calibration temperature. The second calibration temperature is the Curie temperature of the second susceptor material (the peak in the current plot in Figure 6). The first calibration temperature is above the susceptor temperature at which the skin depth of the second susceptor material begins to increase (leading to a temporary decrease in resistance). Thus, the first calibration temperature is above the temperature at which the second susceptor material has maximum penetration. The first calibration temperature is at least 50 degrees Celsius lower than the second calibration temperature. At least the second calibration value can be determined by calibrating the susceptor 160, as will be described in more detail below. The first calibration value and the second calibration value may be stored as calibration values ​​in the memory of the controller 330.

[0088] Conductance (resistance) has a polynomial dependence with respect to temperature, and conductance (resistance) behaves nonlinearly as a function of temperature. However, the first and second calibration values ​​are selected such that the difference between the first and second calibration values ​​is small, allowing this dependence to be approximated linearly between the first and second calibration values, and such that the first and second calibration values ​​are at the top of the operating temperature range. Therefore, to adjust the temperature to the target operating temperature, the conductance is adjusted according to the first and second calibration values ​​through a linear equation. For example, if the first and second calibration values ​​are conductance values, the target conductance value corresponding to the target operating temperature is given by: G Target =G Lower +(x×△G) In the equation, △G is the difference between the first conductance value and the second conductance value, and x is the percentage of △G.

[0089] The controller 330 can control the power supply to the heating arrangement 320 by adjusting the load cycle of the switching transistor 410 of the DC / AC converter 340. For example, during heating, the DC / AC converter 340 continuously generates an alternating current to heat the susceptor 160, and simultaneously supplies a DC voltage V DC and DC current I DC The conductance may be measured every millisecond for a period of preferably 100 milliseconds. If the conductance is monitored by the controller 330, the load cycle of the switching transistor 410 decreases when the conductance reaches or exceeds the value corresponding to the target operating temperature. If the resistance is monitored by the controller 330, the load cycle of the switching transistor 410 decreases when the resistance reaches or falls below the value corresponding to the target operating temperature. For example, the load cycle of the switching transistor 410 may decrease to about 9%. In other words, the switching transistor 410 may be switched to a mode in which it generates pulses only every 10 milliseconds for a duration of 1 millisecond. During this 1 millisecond ON state (conductive state) of the switching transistor 410, the DC supply voltage V DC The value and DC current I DC The value is measured and the conductance is determined. When the conductance decreases (or the resistance increases), indicating that the temperature of susceptor 160 falls below the target operating temperature, a pulse train is again supplied to the gate of transistor 410 at a drive frequency selected for the system.

[0090] Power may be supplied to the inductor 240 by the controller 330 in the form of a series of continuous current pulses. Specifically, power may be supplied to the inductor 240 in a series of pulses, each separated by a certain time interval. The series of continuous pulses may include two or more heating pulses and one or more probe pulses between the continuous heating pulses. The heating pulses have an intensity for heating the susceptor 160. The probe pulses are isolated power pulses that do not heat the susceptor 160, but instead have an intensity for obtaining feedback on the conductance or resistance value, and then on the release (decrease) of the susceptor temperature. The controller 330 may control the power by controlling the duration of the time intervals between the continuous heating pulses of power supplied to the inductor 240 by the DC power supply. Additionally or alternatively, the controller 330 may control the power by controlling the length (in other words, duration) of each of the continuous heating pulses of power supplied to the inductor 240 by the DC power supply.

[0091] The controller 330 is programmed to perform a calibration process to obtain a calibration value in which the conductance is measured at a known temperature of the susceptor 160. The known temperature of the susceptor may be a first calibration temperature corresponding to a first calibration value, and a second calibration temperature corresponding to a second calibration value. Preferably, the calibration process is performed each time the user operates the aerosol generator 200, for example, each time the user inserts an aerosol generating article 100 into the aerosol generator 200.

[0092] During the calibration process, the controller 330 controls the DC / AC converter 340 to continuously or intermittently supply power to the inductor 240 in order to heat the susceptor 160. The controller 330 controls the current I drawn by the power supply. DC , and optionally, power supply voltage V DCThe conductance or resistance associated with the susceptor 160 is monitored by measuring the current. As described above in relation to Figure 6, when the susceptor 160 is heated, the measured current decreases until it reaches a first turning point where the current begins to increase. This first turning point corresponds to the local minimum conductance value (local maximum resistance value). The controller 330 may record the local minimum value of conductance (or local maximum value of resistance) as the first calibration value. The controller may record the conductance or resistance value as the first calibration value at a predetermined time after reaching the minimum current. The conductance or resistance is measured against the current I DC and the measured voltage V DC It can be determined based on the known characteristics of the power supply 310, the power supply voltage V DC It may be assumed that this is approximately constant. The temperature of the susceptor 160 at the first calibration value is referred to as the first calibration temperature. The first calibration temperature is preferably between 150 degrees Celsius and 350 degrees Celsius. More preferably, if the aerosol-forming substrate 110 contains tobacco, the first calibration temperature is 320 degrees Celsius. The first calibration temperature is at least 50 degrees Celsius lower than the second calibration temperature.

[0093] As the controller 330 continues to control the power supplied to the inductor 240 by the DC / AC converter 340, the measured current rises until it reaches a second turning point, after which the measured current begins to decrease (corresponding to the Curie temperature of the second susceptor material). This turning point corresponds to the local maximum conductance value (local minimum resistance value). The controller 330 records the local maximum value of conductance (or local minimum value of resistance) as the second calibration value. The temperature of the susceptor 160 at the second calibration value is referred to as the second calibration temperature. Preferably, the second calibration temperature is between 200°C and 400°C. Once the maximum value is detected, the controller 330 controls the DC / AC converter 340 to interrupt the supply of power to the inductor 240, resulting in a decrease in the temperature of the susceptor 160 and a corresponding decrease in conductance.

[0094] Due to the shape of the graph, the process of continuously heating the susceptor 160 to obtain the first and second calibration values ​​may be repeated at least once. After interrupting the supply of power to the inductor 240, the controller 330 continues to monitor the conductance (or resistance) until a third transition point corresponding to a second minimum conductance value (second maximum resistance value) is observed. Once the third transition point is detected, the controller 330 controls the DC / AC converter 340 to continuously supply power to the inductor 240 until a fourth transition point corresponding to a second maximum conductance value (second minimum resistance value) is detected. The controller 330 stores the conductance or resistance value at or immediately after the third transition point as the first calibration value, and the conductance or resistance value at the current of the fourth transition point as the second calibration value. Repeated measurements of the transition points corresponding to the minimum and maximum currents measured significantly improve subsequent temperature control during user operation for aerosol generation. Preferably, the controller 330 adjusts the power based on conductance or resistance values ​​obtained from a second maximum and a second minimum value, which is more reliable because it may take more time for the heat to dissipate within the aerosol-forming substrate 110 and the susceptor 160.

[0095] To further improve the reliability of the calibration process, the controller 310 may optionally be programmed to perform a preheating process before the calibration process. For example, if the aerosol-forming substrate 110 is particularly dry or in a similar state, the calibration may be performed before heat has diffused into the aerosol-forming substrate 110, reducing the reliability of the calibration value. If the aerosol-forming substrate 110 is wet, the susceptor 160 will take longer to reach the valley temperature (due to the moisture content of the substrate 110).

[0096] To carry out the preheating process, the controller 330 is configured to continuously supply power to the inductor 240. As described above, the current begins to decrease as the temperature of the susceptor 160 rises until it reaches a minimum value. At this stage, the controller 330 is configured to wait for a predetermined period of time to allow the susceptor 160 to cool before continuing heating. Thus, the controller 330 controls the DC / AC converter 340 to interrupt the supply of power to the inductor 240. After the predetermined period, the controller 330 controls the DC / AC converter 340 to supply power until it reaches a minimum value. At the minimum value, the controller controls the DC / AC converter 340 to again interrupt the supply of power to the inductor 240. The controller 330 again waits for the same predetermined period of time to allow the susceptor 160 to cool before continuing heating. This heating and cooling of the susceptor 160 is repeated for a predetermined duration of the preheating process. The predetermined duration of the preheating process is preferably 11 seconds. A preheating process for a predetermined combination is preferably followed by a calibration process lasting 20 seconds.

[0097] If the aerosol-forming substrate 110 is dry, it may reach a first minimum value of the preheating process within a predetermined period, and power interruptions may be repeated until the end of the predetermined period. If the aerosol-forming substrate 110 is wet, it may reach a first minimum value of the preheating process toward the end of the predetermined period. Therefore, by performing the preheating process for a predetermined duration, it is ensured that, regardless of the physical state of the substrate 110, there is sufficient time for the substrate 110 to reach a minimum temperature and a first maximum value in order to prepare for continuous power supply. This allows for calibration as early as possible, but still eliminates the risk that the substrate 110 will not reach the valley beforehand.

[0098] Furthermore, the aerosol generating article 100 may be configured to always reach a minimum value within a predetermined duration of the preheating process. If the minimum value is not reached within a predetermined duration of the preheating process, this may indicate that the aerosol generating article 100, including the aerosol forming substrate 110, is not suitable for use in the aerosol generator 200. For example, the aerosol generating article 100 may contain an aerosol forming substrate 110 that is different from or of lower quality than the aerosol forming substrate 100 intended for use in the aerosol generator 200. As another example, the aerosol generating article 100 may not be configured for use in the heating arrangement 320, for example, if the aerosol generating article 100 and the aerosol generator 200 are manufactured by different manufacturers. Therefore, the controller 330 may be configured to generate a control signal to stop the operation of the aerosol generator 200.

[0099] The preheating process may be performed in response to the acceptance of user input, for example, user activation of the aerosol generator 200. Additionally or alternatively, the controller 330 may be configured to detect the presence of aerosol generating articles 100 in the aerosol generator 200, and the preheating process may be performed in response to the detection of the presence of aerosol generating articles 100 in the cavity 220 of the aerosol generator 200.

[0100] Figure 7 is a graph of conductance against time showing the heating profile of the susceptor 160. The graph shows two successive heating stages, the first heating stage 710 including the preheating process 710A and the calibration process 710B described above, and the second heating stage 720 corresponding to the user operation of the aerosol generator 200 for generating aerosols. Although Figure 7 is shown as a graph of conductance against time, it is understood that the controller 330 may be configured to control the heating of the susceptor between the first heating stage 710 and the second heating stage 720 based on the measured resistance or current, as described above.

[0101] Furthermore, while techniques for controlling the heating of the susceptor between the first heating stage 710 and the second heating stage 720 have been described above based on a determined conductance value or determined resistance value associated with the susceptor, it is understood that the above techniques may be implemented based on a current value measured at the input of the DC / AC converter 340.

[0102] As can be seen from Figure 7, the second heating stage 720 includes multiple conductance steps corresponding to multiple temperature steps from the first operating temperature of the susceptor 160 to the second operating temperature of the susceptor 160. The first operating temperature of the susceptor is the minimum temperature at which the aerosol-forming substrate can form an aerosol in sufficient volume and quantity to provide a satisfactory experience when inhaled by the user. The second operating temperature of the susceptor is the maximum temperature at which it is desirable for the aerosol-forming substrate to be heated for the user to inhale the aerosol. The first operating temperature of the susceptor 160 is above the first calibration temperature of the susceptor 160 at the trough of the current plot shown in Figure 6. The first operating temperature may be between approximately 150°C and approximately 330°C. The second operating temperature of the susceptor is below the second calibration temperature of the susceptor 160 at the Curie temperature of the second susceptor material. The second operating temperature may be between 200°C and 400°C. The difference between the first operating temperature and the second operating temperature is at least 50 degrees Celsius. The first operating temperature of the susceptor is the temperature at which the aerosol-forming substrate 110 forms an aerosol, so that an aerosol is formed during each temperature step.

[0103] Naturally, the temperature steps shown in Figure 7 are illustrative, and the second heating stage 720 includes at least three consecutive temperature steps, preferably two to fourteen temperature steps, most preferably three to eight temperature steps. Each temperature step may have a predetermined duration. Preferably, the duration of the first temperature step is longer than the duration of the subsequent temperature steps. The duration of each temperature step is preferably longer than 10 seconds, preferably 30 to 200 seconds, and more preferably 40 to 160 seconds. The duration of each temperature step may correspond to a predetermined number of user inhalations. Preferably, the first temperature step corresponds to four user inhalations, and each subsequent temperature step corresponds to one user inhalation.

[0104] During the duration of each temperature step, the temperature of the susceptor 160 is maintained at the target operating temperature corresponding to that temperature step. Therefore, during the duration of each temperature step, the controller 330 controls the power supply to the heating arrangement 320 so that the conductance is maintained at a value corresponding to the target operating temperature of each temperature step described above. The target conductance value for each temperature step may be stored in the memory of the controller 330.

[0105] For example, the second heating stage 720 may include five temperature steps, the first temperature step having a duration of 160 seconds, and G Target =G Lower The target conductance value is +(0.09 × ΔG), and the second temperature step has a duration of 40 seconds, and G Target =G Lower The target conductance value is +(0.25 × ΔG), and the third temperature step has a duration of 40 seconds, and G Target =G Lower The target conductance value is +(0.4 × ΔG), and the fourth temperature step has a duration of 40 seconds, and G Target =G Lower The target conductance value is +(0.56 × ΔG), and the fifth temperature step has a duration of 85 seconds, and G Target =G LowerThe target conductance value is +(0.75 × ΔG). These temperature steps can correspond to temperatures of 330°C, 340°C, 345°C, 355°C, and 380°C.

[0106] Figure 8 is a flowchart of method 800 for controlling aerosol generation in the aerosol generator 200. As described above, the controller 330 can be programmed to implement method 800.

[0107] The method begins in step 810, during which the controller 330 detects user operation of the aerosol generator 200 for generating an aerosol. Detection of user operation of the aerosol generator 200 may include detecting user input, for example, user activation of the aerosol generator 200. Additionally or alternatively, detection of user operation of the aerosol generator 200 may include detecting that an aerosol generating article 100 has been inserted into the aerosol generator 200.

[0108] In response to detecting user operation in step 810, the controller 330 may be configured to perform the optional preheating process described above. At the end of a predetermined duration of the preheating process, the controller 330 performs the calibration process (step 820) as described above. Alternatively, the controller 330 may be configured to proceed to step 820 in response to detecting user operation in step 810. After the completion of the calibration process, the controller 330 performs a second heating step in step 840 in which an aerosol is generated.

[0109] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers representing amounts, quantities, percentages, etc., should be understood in all cases as being modified by the term “approximately.” Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges therewith, which may or may not be specifically listed herein. In this context, number A may be considered to include a number that falls within the general standard error of the measurement of the characteristic that number A modifies. In some cases as used in the appended claims, number A may deviate by the percentages listed above, provided that the amount of deviation of A does not substantially affect the basic and novel characteristics(s) of the claimed invention. Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges therewith, which may or may not be specifically listed herein.

Claims

1. A method for controlling aerosol generation in an aerosol generator, wherein the aerosol generator comprises a heating element and a power supply for providing power to the heating element, and the method is The calibration process includes performing a calibration process to measure a calibration value associated with a susceptor, wherein the heating arrangement is configured to inductively heat the susceptor based on the calibration value, and the calibration process is performed i) A step of controlling the power supplied to the heating arrangement to raise the temperature of the susceptor, ii) A step of monitoring the conductance value or resistance value associated with the susceptor, iii) A step of interrupting the supply of power to the heating arrangement when the conductance value reaches its maximum value, or when the resistance value reaches its minimum value, wherein the conductance value at maximum conductance, or the resistance value at minimum resistance, is a second calibration value associated with the susceptor. iv) A step of monitoring the conductance value associated with the susceptor until the conductance value reaches a minimum value, or monitoring the resistance value associated with the susceptor until the resistance value reaches a maximum value, wherein the conductance value at the minimum conductance, or the resistance value at the maximum resistance, is a first calibration value associated with the susceptor. A method wherein the calibration process is performed in response to detecting a control signal associated with the termination of a preheating process, and the preheating process has a predetermined duration.

2. The method according to claim 1, wherein the susceptor comprises a first material having a first Curie temperature and a second material having a second Curie temperature, the second Curie temperature being lower than the first Curie temperature, and the second calibration temperature of the susceptor associated with the second calibration conductance value corresponding to the second Curie temperature of the second material.

3. The method according to claim 1 or 2, wherein the calibration process is performed during user operation of the aerosol generator.

4. The power supplied to the heating arrangement is controlled to maintain the conductance value associated with the susceptor between the first calibration value and the second calibration value. The method according to any one of claims 1 to 3, wherein controlling the power supplied to the heating arrangement includes controlling the power supplied to the heating arrangement to gradually increase the conductance value associated with the susceptor from a first operating conductance value to a second operating conductance value, and the temperature of the susceptor associated with the first operating conductance value is sufficient for the aerosol-forming substrate to form an aerosol.

5. The power supplied to the heating arrangement is controlled to maintain the resistance value associated with the susceptor between the first calibration value and the second calibration value. The method according to any one of claims 1 to 3, wherein controlling the power supplied to the heating arrangement includes controlling the power supplied to the heating arrangement to gradually decrease the resistance value associated with the susceptor from a first operating resistance value to a second operating resistance value, and the temperature of the susceptor associated with the first operating resistance value is sufficient for the aerosol-forming substrate to form an aerosol.

6. The method according to claim 1, further comprising performing the preheating process, the preheating process comprising: i) controlling the power supplied to the heating arrangement to raise the temperature of the susceptor; ii) monitoring a conductance or resistance value associated with the susceptor; and iii) interrupting the supply of power to the heating arrangement when the conductance value reaches a minimum or the resistance value reaches a maximum.

7. The method according to claim 6, further comprising repeating steps i) to iii) of the preheating process until the end of the predetermined duration of the preheating process if the conductance value reaches a minimum value or the resistance value reaches a maximum value before the end of the predetermined duration of the preheating process.

8. The method according to any one of claims 1 to 6, further comprising generating a control signal to stop the operation of the aerosol generator if the conductance value does not reach a minimum value or the resistance value does not reach a maximum value during the predetermined duration of the preheating process.

9. The method according to any one of claims 1 to 3, wherein the aerosol generator is configured to receive an aerosol generating article, the aerosol generating article comprises the susceptor and the aerosol forming substrate, and the preheating process is performed in response to the detection of the aerosol generating article.

10. Aerosol generator, A power supply for providing DC supply voltage and DC current, A power supply electronic circuit connected to the power supply, wherein the power supply electronic circuit comprises a DC / AC converter, an inductor connected to the DC / AC converter to generate an alternating magnetic field when energized by the alternating current from the DC / AC converter, the inductor being capable of being coupled to a susceptor, and the susceptor being configured to heat an aerosol-forming substrate, and A power supply electronic circuit includes a controller configured to perform a calibration process to measure a calibration value associated with a susceptor, wherein the power supply electronic circuit is configured to inductively heat the susceptor based on the calibration value, and the calibration process is performed i) A step of controlling the power supplied to the inductor to raise the temperature of the susceptor, ii) A step of monitoring the conductance value or resistance value associated with the susceptor, iii) A step of interrupting the supply of power to the inductor when the conductance value reaches its maximum value, or when the resistance value reaches its minimum value, wherein the conductance value at maximum conductance or the resistance value at minimum resistance is a second calibration value associated with the susceptor. iv) A step of monitoring the conductance value associated with the susceptor until the conductance value reaches a minimum value, or monitoring the resistance value associated with the susceptor until the resistance value reaches a maximum value, wherein the conductance value at the minimum conductance, or the resistance value at the maximum resistance, is a first calibrated conductance value associated with the susceptor. An aerosol generator wherein the controller is configured to perform the calibration process in response to detecting a control signal associated with the termination of the preheating process, and the preheating process has a predetermined duration.

11. The aerosol generator according to claim 10, wherein the second operating temperature of the susceptor associated with the second calibration conductance value corresponds to the Curie temperature of the susceptor material.

12. The aerosol generator according to claim 10 or 11, wherein the controller is further configured to control the power supplied to the inductor to maintain the conductance value associated with the susceptor between the first calibration value and the second calibration value.

13. The aerosol generator according to claim 10 or 11, wherein the controller is further configured to control the power supplied to the inductor to maintain the resistance value associated with the susceptor between the first calibration value and the second calibration value.

14. The calibration process further includes: v) controlling the power supplied to the heating arrangement to raise the temperature of the susceptor when the conductance value reaches the minimum value or the resistance value reaches the maximum value; vi) monitoring the conductance value or the resistance value associated with the susceptor; and vii) interrupting the supply of power to the inductor when the conductance value reaches a second maximum value or the resistance value reaches a second minimum value, wherein the conductance value at the second maximum value is a fourth calibration value associated with the susceptor, or at the second minimum value The aerosol generator according to claim 10 or 11, comprising: interrupting the current, wherein the resistance value is a fourth calibration value associated with the susceptor; iv) monitoring the conductance value associated with the susceptor until the conductance value reaches a second minimum value, wherein the conductance value at the second minimum value is a third calibration value associated with the susceptor; or monitoring the resistance value associated with the susceptor until the resistance value reaches a second maximum value, wherein the resistance value at the second maximum value is a third calibration value associated with the susceptor.

15. The aerosol generator according to claim 14, wherein the controller is further configured to control the power supplied to the inductor to maintain the conductance value associated with the susceptor between the third calibration value and the fourth calibration value.

16. The aerosol generator according to claim 14, wherein the controller is further configured to control the power supplied to the inductor to maintain the resistance value associated with the susceptor between the third calibration value and the fourth calibration value.

17. The controller is configured to perform the calibration process in response to the detection of an aerosol-generating article containing the susceptor, or The aerosol generator according to any one of claims 10 to 16, wherein the controller is configured to perform the calibration process in response to detecting user input.

18. The aerosol generator according to claim 10, wherein the controller is further configured to carry out the preheating process, the preheating process comprising: i) controlling the power supplied to the inductor to raise the temperature of the susceptor; ii) monitoring a conductance or resistance value associated with the susceptor; and iii) interrupting the supply of power to the inductor when the conductance value reaches a minimum or the resistance value reaches a maximum.

19. The controller is configured to repeat steps i) to iii) of the preheating process until the end of the predetermined duration of the preheating process if the conductance value reaches a minimum value or the resistance value reaches a maximum value before the end of the predetermined duration of the preheating process. The aerosol generator according to claim 18, wherein the controller is configured to generate a control signal for stopping the operation of the aerosol generator if the conductance value of the susceptor does not reach a minimum value or the resistance value does not reach a maximum value during the predetermined duration of the preheating process.

20. An aerosol generating system comprising the aerosol generating device according to any one of claims 10 to 19 and an aerosol generating article, wherein the aerosol generating article includes the aerosol forming substrate and the susceptor.

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