Aerosol generator and system equipped with an induction heating device, and method for operating the same.

Abstract

A method (800) for controlling aerosol generation in an aerosol generating device (200) is provided, the method including performing (820) a calibration process during user operation of the aerosol generating device (200) to define first and second calibration values ​​of an induction heating device (320) during a first heating stage for generating an aerosol, the first calibration value being associated with a first calibration temperature of a susceptor (160) inductively coupled to the induction heating device, the second calibration value being associated with a second calibration temperature of the susceptor, the susceptor being configured to heat an aerosol-forming substrate (110), and controlling (840) power provided to the induction heating device to maintain a target operating value of the induction heating device within the first and second calibration values ​​during the second heating stage.

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 including 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 comprises an inductor inductively coupled 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 can be controlled by controlling the temperature of the susceptor. Therefore, it is important for such an aerosol generator to accurately monitor and control the temperature of the susceptor to ensure optimal generation and delivery of aerosols to the user.

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

[0004] According to embodiments of the present invention, a method for controlling aerosol generation in an aerosol generator is provided. The device may include an induction heater and a power supply for supplying power to the induction heater. The method may include: performing a calibration process to define a first calibration value and a second calibration value for the induction heater during a first heating phase of user operation of the aerosol generator for generating an aerosol, wherein the first calibration value is associated with a first calibration temperature of a susceptor inductively coupled to the induction heater, and the second calibration value is associated with a second calibration temperature of the susceptor, and the susceptor is configured to heat an aerosol-forming substrate; and controlling the power supplied to the induction heater to maintain a target operating value of the induction heater within the first and second calibration values ​​during a second heating phase of user operation of the aerosol generator.

[0005] Performing a calibration process during user operation of the aerosol generator and using the calibration values ​​obtained from the calibration process to control the power supplied to the induction heating device 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, as the aerosol generator can be calibrated for multiple 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.

[0006] An induction heating device may comprise a DC / AC converter and an inductor connected to the DC / AC converter. A susceptor may be inductively coupled and placed on the inductor. Power from a power source can be continuously supplied to the inductor via the DC / AC converter. The current, conductance, or resistance of the induction heating device can be determined at the input side of the DC / AC converter based on measurements of the DC current drawn from the power source and optionally the DC supply voltage of the power source.

[0007] The second calibration temperature of the susceptor may correspond to the Curie temperature of the susceptor material. The first calibration temperature of the susceptor may correspond to the temperature at the maximum permeability of the susceptor material.

[0008] The susceptor may comprise a first susceptor material having a first Curie temperature and a second susceptor material having a second Curie temperature, the second being lower than the first. The second temperature of the susceptor may correspond to the second Curie temperature of the second susceptor material.

[0009] The first and second susceptor materials are preferably two separate susceptor materials joined together and therefore in physical contact with each other, thereby ensuring that both susceptor materials have the same temperature by thermal conduction. The two susceptor materials are preferably two layers or strips joined together along one of their main surfaces. The susceptor may further include a further third layer of susceptor material. The third layer of susceptor material may be made from the first susceptor material. The thickness of the third layer of susceptor material may be less than the thickness of the second layer of the second susceptor material.

[0010] The first calibration value may be a first conductance value, the second calibration value may be a second conductance value, and the target operating value may be a target conductance value. Performing the calibration process may include (i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor, (ii) monitoring the conductance value associated with the susceptor, (iii) interrupting the power supply to the induction heating device when the conductance value reaches a maximum value, wherein the conductance value at the maximum value corresponds to the second calibration value, and (iv) monitoring the conductance value until the conductance value reaches a minimum value, wherein the conductance value at the minimum value corresponds to the first calibration value.

[0011] Monitoring the conductance value may include measuring the DC current drawn from the power supply at the input side of the DC / AC converter. Monitoring the conductance value may further include measuring the DC voltage at the power supply 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 forms part of an article) and the apparent conductance thus determined (because the susceptor imparts the conductance of the coupled LCR circuit (of the DC / AC converter), and a large portion of the load (R) is due to the resistance of the susceptor). Conductance is 1 / R. Therefore, when the inventors refer to the conductance of a susceptor in this text, they are actually referring to the apparent conductance when the susceptor forms part of a separate aerosol-generating article.

[0012] Performing the calibration process may further include repeating steps (i) to (iv) in response to determining that the conductance value has reached a minimum value. The first calibration value and the second calibration value may correspond to the conductance values measured during at least the first repetition of steps (i) to (iv).

[0013] The first calibration value may be a first resistance value, the second calibration value may be a second resistance value, and the target operating value may be a target resistance value. Performing the calibration process may include: i) controlling the power supplied to the induction heating device to increase the temperature of the susceptor; ii) monitoring the resistance value associated with the susceptor; iii) when the resistance value reaches the minimum value, interrupting the power supply to the induction heating device, wherein the resistance value at the minimum value corresponds to the second calibration value; and iv) monitoring the resistance value until it reaches the maximum value, wherein the resistance value at the maximum value corresponds to the first calibration value.

[0014] Monitoring the resistance value may include measuring the DC current drawn from the power supply on the input side of the DC / AC converter. Monitoring the resistance value may further include measuring the DC voltage at the power supply on the input side of the DC / AC converter.

[0015] Performing the calibration process may further include repeating steps i) to iv) in response to determining that the resistance value has reached the maximum value. The first calibration value and the second calibration value may correspond to the resistance values measured during at least the first repetition of steps i) to iv).

[0016] The first calibration value may be a first current value, the second calibration value may be a second current value, and the target operating value may be a target current value.

[0017] Performing a calibration process may include: i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; ii) monitoring the current value associated with the susceptor; iii) interrupting the power supply to the induction heating device when the current value reaches a maximum value, wherein the current value at the maximum value corresponds to a second calibration value; and iv) monitoring the conductance value until the conductance value reaches a minimum value, wherein the current value at the minimum value corresponds to a first calibration value.

[0018] Monitoring the current value may include measuring the DC current drawn from the power supply at the input side of the DC / AC converter. Monitoring the current value may further include measuring the DC voltage at the power supply at the input side of the DC / AC converter.

[0019] Performing the calibration process may further include repeating steps i) to iv) in response to determining that the current value has reached a minimum value. The first and second calibration values ​​may correspond to the current values ​​measured during at least the first iteration of steps i) to iv).

[0020] The calibration process is rapid and reliable, without delaying aerosol generation. Furthermore, by repeating the steps of the calibration process, the time for which heat is distributed within the substrate increases, significantly improving subsequent temperature regulation.

[0021] The method may further include performing a calibration process in response to detecting one or more of the following during the second heating stage: a predetermined period of time, a predetermined number of user smoke inhalations, and a predetermined voltage value of the power supply.

[0022] Conditions may change during user operation of the aerosol generator. For example, the susceptor may be moved relative to the induction heating device, and the power supply (e.g., battery) may lose some efficiency over time. Therefore, performing a calibration process periodically ensures the reliability of the calibration values, thereby ensuring that optimal temperature control is maintained throughout the entire use of the aerosol generator.

[0023] The method may further include performing a preheating process during the first heating stage. The preheating process may be performed before the calibration process, and the preheating process may have a predetermined duration.

[0024] The preheating process may include (i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor, (ii) monitoring the conductance value associated with the susceptor with the power supply, and (iii) interrupting the power supply to the susceptor when the conductance value reaches a minimum value.

[0025] The preheating process may further include repeating steps (i) to (iii) of the preheating process until the end of the predetermined period of the preheating process, if the conductance value reaches a minimum before the end of the predetermined period of the preheating process. Within the predetermined time, heat can diffuse within the substrate, regardless of the physical state of the substrate (e.g., whether the substrate is dry or wet), until it reaches the minimum conductance value measured during the calibration process. This ensures the reliability of the calibration process.

[0026] The preheating process may further include stopping the operation of the aerosol generator if the susceptor conductance value does not reach a minimum value during a predetermined period of the preheating process. The susceptor is preferably contained within an aerosol generating article configured to be inserted into the aerosol generator. Aerosol generating articles not configured for use with an aerosol generator will not behave in the same way as approved aerosol generating articles. Specifically, the susceptor conductance will not reach a minimum value during a predetermined period of the preheating process. This thus prevents the use of unapproved aerosol generating articles.

[0027] The preheating process may include i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; ii) monitoring the resistance value associated with the susceptor with the power supply; and iii) interrupting the power supply to the susceptor when the resistance value reaches its maximum value.

[0028] If the resistance value reaches its maximum value before the end of the predetermined period of the preheating process, steps (i) to (iii) of the preheating process may be repeated until the end of the predetermined period of the preheating process.

[0029] If the resistance value associated with the susceptor does not reach its maximum value during a predetermined period of the preheating process, the aerosol generator may be shut down.

[0030] The preheating process may include i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; ii) monitoring the current value associated with the susceptor at the power supply; and iii) interrupting the power supply to the susceptor when the current value reaches a minimum value.

[0031] If the current value reaches its minimum before the end of the predetermined period of the preheating process, steps (i) to (iii) of the preheating process may be repeated until the end of the predetermined period of the preheating process.

[0032] If the current value associated with the susceptor does not reach a minimum value during a predetermined period of the preheating process, the aerosol generator may be shut down.

[0033] During the preheating process, power from the power supply can be continuously supplied to the inductor via a DC / AC converter.

[0034] The calibration process may be performed in response to the detection of the end of a predetermined period of the preheating process. The preheating process may be performed in response to the detection of user input. The user input may correspond to the user activation of the aerosol generator.

[0035] The aerosol generator may be configured to removably receive an aerosol generating article, which includes a susceptor and an aerosol-forming substrate, and the preheating process is carried out in response to the detection of the presence of the aerosol generating article in the aerosol generator. The predetermined period may be 10 to 15 seconds.

[0036] The susceptor is preferably included in an aerosol generating article configured to be inserted into an aerosol generator. Aerosol generating articles not configured for use with an aerosol generator will not behave in the same way as approved aerosol generating articles. Specifically, the conductance of the susceptor will not reach its minimum value during a predetermined period of the preheating process. This therefore prevents the use of unapproved aerosol generating articles.

[0037] Controlling the power supplied to the induction heater during the second heating stage may further include controlling the power supplied to the induction heater to gradually increase the target operating value from a first target operating value associated with the first operating temperature of the susceptor to a second target operating value associated with the second operating temperature of the susceptor. The first operating temperature may be sufficient for the aerosol-forming substrate to form an aerosol.

[0038] By controlling the power supplied to the induction heating device to gradually increase the susceptor temperature, it becomes possible to generate aerosols over a sustained period, including multiple puffs, such as 14, or a complete user experience at predetermined time intervals, such as 6 minutes, while delivery (nicotine, flavor, aerosol volume, etc.) remains substantially constant with each puff throughout the user experience. Specifically, a gradual increase in susceptor temperature is achieved when the temperature prevents a decrease in aerosol delivery due to substrate depletion and reduced heat diffusion over time. Furthermore, the gradual increase in temperature allows heat to spread within the substrate at each step.

[0039] The first operating temperature may be between 150°C and 330°C, and the second operating temperature may be between 200°C and 400°C. The temperature difference between the first and second operating temperatures may be at least 30°C.

[0040] The gradual increase in the target operating value may include at least three consecutive steps, each having a duration.

[0041] Controlling the power supplied to the induction heating device may further include, for each step, maintaining the target operating value of the induction heating device at a value associated with each step during the duration of each step. Maintaining the target operating value of the induction heating device may include determining one of the current, conductance, or resistance values ​​associated with the susceptor, and adjusting the power supplied to the induction heating device based on the determined conductance value.

[0042] The duration of each step is at least 10 seconds. The duration of each step may be 30 to 200 seconds. The duration of each step may be 40 to 160 seconds. The duration of each step may be predetermined. The duration of each step may correspond to a predetermined number of user smoke inhalations. The first step of a series of steps may have a longer duration than the subsequent temperature steps.

[0043] Power from the power source may be supplied to the inductor as multiple pulses via a DC / AC converter, with each pulse separated by a time interval.

[0044] Controlling the power supplied to an induction heating device may include controlling the time interval between each of the multiple pulses.

[0045] Controlling the power supplied to an induction heating device may include controlling the length of each pulse in a set of pulses.

[0046] The first and second heating stages may be user operation stages of the aerosol generator.

[0047] The first calibration temperature may be between 150°C and 350°C, and the second calibration temperature may be between 200°C and 400°C. The temperature difference between the first and second calibration temperatures may be at least 50°C.

[0048] Another embodiment of the present invention provides an aerosol generator. The aerosol generator may include 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 may include 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, the inductor being coupleable to a susceptor, and the susceptor being configured to heat an aerosol-forming substrate, and a controller. The controller may perform a calibration process to define a first calibration value and a second calibration value of the power supply electronic circuit during a first heating phase during user operation of the aerosol generator for generating an aerosol, the first calibration value being associated with a first calibration temperature of the susceptor, and the second calibration value being associated with a second calibration temperature of the susceptor, and may control the power supplied to the power supply electronic circuit to maintain a target operating value of the power supply electronic circuit within the first and second calibration values ​​during a second heating phase during user operation of the aerosol generator for generating an aerosol.

[0049] Power from the power supply can be continuously supplied to the inductor via a DC / AC converter.

[0050] The second calibration temperature of the susceptor may correspond to the Curie temperature of the susceptor material. The first calibration temperature of the susceptor may correspond to the temperature at the maximum permeability of the susceptor material. The first calibration value may be the first conductance value, the second calibration value is the second conductance value, and the target operating value is the target conductance value. Performing the calibration process may include (i) controlling the power supplied to the power supply electronics to raise the temperature of the susceptor; (ii) monitoring the conductance value associated with the susceptor; (iii) interrupting the power supply to the power supply electronics when the conductance value reaches a maximum value, wherein the conductance value at the maximum value corresponds to the second calibration value; and (iv) monitoring the conductance value until the conductance value reaches a minimum value, wherein the conductance value at the minimum value corresponds to the first calibration value.

[0051] Monitoring conductance values ​​may include measuring the DC current drawn from the power supply at the input side of a DC / AC converter. Monitoring conductance values ​​may further include measuring the DC voltage at the power supply at the input side of a DC / AC converter.

[0052] Performing the calibration process may further include repeating steps (i) to (iv) in response to determining that the conductance value has reached a minimum value. The first and second calibration values ​​may correspond to the conductance values ​​measured during at least the first iteration of steps (i) to (iv).

[0053] The first calibration value may be the first resistance value, the second calibration value may be the second resistance value, and the target operating value may be the target resistance value. Performing the calibration process may include: i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; ii) monitoring the resistance value associated with the susceptor; iii) interrupting the power supply to the induction heating device when the resistance value reaches a minimum value, wherein the resistance value at the minimum value corresponds to the second calibration value; and iv) monitoring the resistance value until the resistance value reaches a maximum value, wherein the resistance value at the maximum value corresponds to the first calibration value.

[0054] Monitoring resistance may include measuring the DC current drawn from the power supply at the input side of a DC / AC converter. Monitoring resistance may further include measuring the DC voltage at the power supply at the input side of a DC / AC converter.

[0055] Performing the calibration process may further include repeating steps i) to iv) in response to determining that the resistance value has reached its maximum value.

[0056] The first and second calibration values ​​may correspond to resistance values ​​measured during at least the first iteration of steps i) to iv).

[0057] The first calibration value may be the first current value, the second calibration value may be the second current value, and the target operating value may be the target current value. Performing the calibration process may include i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; ii) monitoring the current value associated with the susceptor; iii) interrupting the power supply to the induction heating device when the current value reaches a maximum value, wherein the current value at the maximum value corresponds to the second calibration value; and iv) monitoring the conductance value until the conductance value reaches a minimum value, wherein the current value at the minimum value corresponds to the first calibration value.

[0058] Monitoring the current value may include measuring the DC current drawn from the power supply at the input side of the DC / AC converter. Monitoring the current value may further include measuring the DC voltage at the power supply at the input side of the DC / AC converter.

[0059] Performing the calibration process may further include repeating steps i) to iv) in response to determining that the current value has reached a minimum value. The first and second calibration values ​​may correspond to the current values ​​measured during at least the first iteration of steps i) to iv).

[0060] The controller may be further configured to perform a calibration process in response to detecting one or more of the following during the second heating stage: a predetermined period of time, a predetermined number of user smoke inhalations, and a predetermined voltage value of the power supply.

[0061] The controller may also be configured to perform a preheating process during the first heating stage. The controller may also be configured to perform a preheating process before the calibration process, and the preheating process has a predetermined duration.

[0062] The preheating process may include (i) controlling the power supplied to the power supply electronics circuit to raise the temperature of the susceptor, (ii) monitoring the conductance value associated with the susceptor at the power supply, and (iii) interrupting the power supply to the power supply electronics circuit when the conductance value reaches a minimum value. During the preheating process, power from the power supply is continuously supplied to the inductor via a DC / AC converter.

[0063] The controller may be further configured to repeat steps i) to iii) of the preheating process until the end of the predetermined period of the preheating process if the conductance value reaches a minimum value before the end of the predetermined period of the preheating process.

[0064] The controller may also be configured to generate a control signal that stops the aerosol generator from operating if the susceptor conductance value does not reach a minimum value during a predetermined period of the preheating process.

[0065] The preheating process may include i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; ii) monitoring the resistance value associated with the susceptor with the power supply; and iii) interrupting the power supply to the susceptor when the resistance value reaches its maximum value.

[0066] The controller may also be configured to repeat steps (i) to (iii) of the preheating process until the end of the predetermined period of the preheating process if the resistance value reaches its maximum value before the end of the predetermined period of the preheating process.

[0067] The controller may also be configured to generate a control signal that stops the aerosol generator from operating if the resistance value associated with the susceptor does not reach its maximum value during a predetermined period of the preheating process.

[0068] The preheating process may include i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; ii) monitoring the current value associated with the susceptor at the power supply; and iii) interrupting the power supply to the susceptor when the current value reaches a minimum value.

[0069] The controller may also be configured to repeat steps (i) to (iii) of the preheating process until the end of the predetermined period of the preheating process if the current value reaches a minimum value before the end of the predetermined period of the preheating process.

[0070] The controller may also be configured to generate a control signal that stops the aerosol generator from operating if the current value associated with the susceptor does not reach a minimum value during a predetermined period of the preheating process. The controller may also be configured to perform a calibration process in response to detecting the end of a predetermined period of the preheating process.

[0071] The controller may be configured to perform a preheating process in response to detecting user input. User input may correspond to user activation of the aerosol generator.

[0072] The controller may be configured to perform a preheating process in response to detecting the presence of an aerosol-generating object within a predetermined threshold distance of the inductor. The predetermined duration of the preheating process may be 10 to 15 seconds.

[0073] Controlling the power supplied to the power supply electronics circuit during the second heating stage may further include controlling the power supplied to the power supply electronics circuit to gradually increase the target operating value from a first target operating value associated with the first operating temperature of the susceptor to a second target operating value associated with the second operating temperature of the susceptor.

[0074] The first operating temperature may be sufficient for the aerosol-forming substrate to form an aerosol.

[0075] The first operating temperature may be between 150°C and 330°C, and the second operating temperature may be between 200°C and 400°C. The temperature difference between the first and second operating temperatures may be at least 30°C.

[0076] The gradual increase in the target operating value may include at least three consecutive steps, each having a duration.

[0077] Controlling the power supplied to the power supply electronics may further include, for each step, maintaining the target operating value of the power supply electronics at the value associated with each step during the duration of each step.

[0078] Maintaining the operating conductance value of the power supply electronics may include determining one of the current, conductance, or resistance values ​​associated with the susceptor, and adjusting the power supplied to the power supply electronics based on the determined conductance value. The power supply electronics may further include a current sensor configured to measure the DC current drawn from the power supply at the input side of the DC / AC converter. The power supply electronics may further include a voltage sensor configured to measure the DC supply voltage of the power supply at the input side of the DC / AC converter. The duration of each step may be at least 10 seconds. The duration of each step may be 30 to 200 seconds. The duration of each step may be 40 to 160 seconds. The duration of each step may be predetermined. The duration of each step may correspond to a predetermined number of user smoke inhalations. The first step of a series of steps may have a longer duration than the subsequent steps.

[0079] Power from a power source may be supplied to an inductor as multiple pulses via a DC / AC converter, with each pulse separated by a time interval. Controlling the power supplied to the power supply electronics may include controlling the time interval between each of the multiple pulses. Controlling the power supplied to the power supply electronics may also include controlling the length of each of the multiple pulses.

[0080] The first and second heating stages may be user operation stages of the aerosol generator.

[0081] The first calibration temperature may be between 150°C and 350°C, and the second calibration temperature may be between 200°C and 400°C. The temperature difference between the first and second calibration temperatures may be at least 50°C.

[0082] The power supply electronic circuit may further include a matching network for matching the impedance of the inductor to the impedance of the susceptor.

[0083] The aerosol generator may further include a housing having a cavity configured to receive an aerosol generating article, the aerosol generating article comprising an aerosol forming substrate and a susceptor.

[0084] According to another embodiment of the present invention, an aerosol generating system is provided comprising the aerosol generating device and aerosol generating article described above. The aerosol generating article may comprise an aerosol forming substrate and a susceptor.

[0085] The susceptor may comprise a first layer made of a first material and a second layer made of a second material, wherein the first material is positioned in physical contact with the second material. The first material may be one of aluminum, iron, and stainless steel, and the second material may be nickel or a nickel alloy. The first material may have a first Curie temperature, and the second 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 second Curie temperature of the second susceptor material.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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. Suitable examples of aerosol-forming bodies are glycerin and propylene glycol.

[0091] As used herein, “aerosol cooling element” refers to a component of an aerosol-generating article located downstream of an aerosol-forming substrate, such that during use, aerosols formed by volatile compounds released from the aerosol-forming 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.

[0092] As used herein, the term “mouthpiece” means 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.

[0093] As used herein, the term “susceptor” refers to an element comprising a material having the ability to convert magnetic field energy into heat. When a susceptor is located 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.

[0094] Where 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 positions of components or parts of components of an aerosol generator in relation 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 an aerosol generator may also be referred to as 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 referred to as 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.

[0095] Where used herein in reference to an aerosol-generating article, the terms “upstream” and “front,” and “downstream” and “rear” are used to describe the relative positions of components or parts of components of an aerosol-generating article in relation to the direction through which air flows during use of the aerosol-generating article. The aerosol-generating article according to the present invention has a proximal end through which an aerosol exits the article during use. The proximal end of an aerosol-generating article may also be referred to as the mouth end or the downstream end. The mouth end is downstream of the distal end. The distal end of an aerosol-generating article may also be referred to as the upstream end. Components or parts of components 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 front 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 rear 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.

[0096] As used herein, the term “inductively coupled” refers to heating of a susceptor when it is penetrated by an alternating magnetic field. Heating is caused by the generation of eddy currents within the susceptor. Heating is also caused by magnetic hysteresis losses.

[0097] As used herein, the term "inhalation" means the act of a user inhaling an aerosol into their body through their mouth or nose.

[0098] As used herein, the term “value associated with current” refers to a value determined from current measurements such as current, conductance, and resistance. Current measurements are performed in heating devices (also known as power supply electronic circuits). In particular, DC current may be measured at the input side of a DC / AC converter.

[0099] As used herein, the term “limit” refers to the maximum or minimum value of a function or set of values ​​within a given range or over its entire range.

[0100] 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.

[0101] Example 1: A method for controlling aerosol generation in an aerosol generator, wherein the device comprises an induction heating device and a power supply for supplying power to the induction heating device, the method comprising: performing a calibration process to define a first calibration value and a second calibration value of the induction heating device during a first heating phase of user operation of the aerosol generator for generating an aerosol, wherein the first calibration value is associated with a first calibration temperature of a susceptor inductively coupled to the induction heating device, and the second calibration value is associated with a second calibration temperature of the susceptor, and the susceptor is configured to heat an aerosol-forming substrate; and controlling the power supplied to the induction heating device to maintain a target operating value of the induction heating device within the first and second calibration values ​​during a second heating phase of user operation of the aerosol generator. Example 2: The method according to Example 1, wherein the second calibration temperature of the susceptor corresponds to the Curie temperature of the susceptor material, and the first calibration temperature of the susceptor corresponds to the temperature of maximum permeability of the susceptor material. Example 3: The method according to Example 1 or 2, wherein the susceptor comprises a first susceptor material having a first Curie temperature and a second susceptor 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 corresponds to the second Curie temperature of the second susceptor material. Example 4: The method according to any one of Examples 1 to 3, wherein the first calibration value is the first conductance value, the second calibration value is the second conductance value, and the target operating value is the target conductance value. Example 5: The method according to Example 4, wherein the calibration process includes (i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; (ii) monitoring the conductance value associated with the susceptor; (iii) interrupting the power supply to the induction heating device when the conductance value reaches a maximum value, wherein the conductance value at the maximum value corresponds to a second calibration value; and (iv) monitoring the conductance value until the conductance value reaches a minimum value, wherein the conductance value at the minimum value corresponds to a first calibration value. Example 6: The method according to Example 5, wherein monitoring the conductance value includes measuring the DC current drawn from the power supply at the input side of the DC / AC converter. Example 7: The method according to Embodiment 6, further comprising monitoring the conductance value at the input side of the DC / AC converter and measuring the DC voltage of the power supply. Example 8: The method according to any one of Examples 5 to 7, further comprising repeating steps (i) to (iv) in response to determining that the calibration process has reached a minimum value. Example 9: The method according to Example 8, wherein the first calibration value and the second calibration value correspond to conductance values ​​measured during at least the first iteration of steps (i) to (iv). Example 10: The method according to any one of Examples 1 to 3, wherein the first calibration value is the first resistance value, the second calibration value is the second resistance value, and the target operating value is the target resistance value. Example 11: The method according to Example 10, wherein the calibration process includes: i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; ii) monitoring the resistance value associated with the susceptor; iii) interrupting the power supply to the induction heating device when the resistance value reaches a minimum value, wherein the resistance value at the minimum value corresponds to a second calibration value; and iv) monitoring the resistance value until the resistance value reaches a maximum value, wherein the resistance value at the maximum value corresponds to a first calibration value. Example 12: The method according to Example 11, wherein monitoring the resistance value includes measuring the DC current drawn from the power supply at the input side of a DC / AC converter. Example 13: The method according to Example 12, further comprising monitoring the resistance value at the input side of a DC / AC converter and measuring the DC voltage at the power supply. Example 14: The method according to any one of Examples 11 to 13, further comprising repeating steps i) to iv) in response to determining that the calibration process has reached its maximum value. Example 15: The method according to Example 14, wherein the first calibration value and the second calibration value correspond to the resistance values ​​measured during at least the first iteration of steps i) to iv). Example 16: The method according to any one of Examples 1 to 3, wherein the first calibration value is the first current value, the second calibration value is the second current value, and the target operating value is the target current value. Example 17: The method according to Example 16, wherein the calibration process includes: i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; ii) monitoring the current value associated with the susceptor; iii) interrupting the power supply to the induction heating device when the current value reaches a maximum value, wherein the current value at the maximum value corresponds to a second calibration value; and iv) monitoring the conductance value until the conductance value reaches a minimum value, wherein the current value at the minimum value corresponds to a first calibration value. Example 18: The method according to Example 17, wherein monitoring the current value includes measuring the DC current drawn from the power supply at the input side of the DC / AC converter. Example 19: The method according to Example 18, further comprising monitoring the current value at the input side of a DC / AC converter and measuring the DC voltage at the power supply. Example 20: The method according to any one of Examples 17 to 19, further comprising repeating steps i) to iv) in response to determining that the calibration process has reached a minimum value. Example 21: The method according to Example 20, wherein the first calibration value and the second calibration value correspond to the current values ​​measured during at least the first iteration of steps i) to iv). Example 22: The method according to any one of Examples 1 to 21, further comprising performing a calibration process during the second heating stage in response to detecting one or more of a predetermined period, a predetermined number of user smoke inhalations, and a predetermined voltage value of the power supply. Example 23: The method according to any one of Examples 1 to 22, further comprising performing a preheating process during the first heating stage, wherein the preheating process is performed before the calibration process, and the preheating process has a predetermined duration. Example 24: The method according to Example 23, wherein the preheating process includes (i) controlling the power supplied to an induction heating device to raise the temperature of the susceptor; (ii) monitoring the conductance value associated with the susceptor with the power supply; and (iii) interrupting the power supply to the susceptor when the conductance value reaches a minimum value. Example 25: The method according to Example 24, further comprising repeating steps (i) to (iii) of the preheating process until the end of the predetermined period of the preheating process if the conductance value reaches a minimum value before the end of the predetermined period of the preheating process. Example 26: The method according to Example 24, further comprising stopping the operation of the aerosol generator if the conductance value associated with the susceptor does not reach a minimum during a predetermined period of the preheating process. Example 27: The method according to Example 23, wherein the preheating process includes the steps of i) controlling the power supplied to an induction heating device to raise the temperature of the susceptor, ii) monitoring the resistance value associated with the susceptor with the power supply, and iii) interrupting the power supply to the susceptor when the resistance value reaches its maximum value. Example 28: The method according to Example 27, further comprising repeating steps (i) to (iii) of the preheating process until the end of the predetermined period of the preheating process if the resistance value reaches its maximum value before the end of the predetermined period of the preheating process. Example 29: The method according to Example 27, further comprising stopping the operation of the aerosol generator if the resistance value associated with the susceptor does not reach its maximum value during a predetermined period of the preheating process. Example 30: The method according to Example 23, wherein the preheating process includes the steps of i) controlling the power supplied to an induction heating device to raise the temperature of the susceptor, ii) monitoring the current value associated with the susceptor at the power supply, and iii) interrupting the power supply to the susceptor when the current value reaches a minimum value. Example 31: The method according to Example 30, further comprising repeating steps (i) to (iii) of the preheating process until the end of the predetermined period of the preheating process if the current value reaches a minimum value before the end of the predetermined period of the preheating process. Example 32: The method according to Example 30, further comprising stopping the operation of the aerosol generator if the current value associated with the susceptor does not reach a minimum value during a predetermined period of the preheating process. Example 33: The method according to any one of Examples 23 to 32, wherein during the preheating process, power from the power supply is continuously supplied to the inductor via a DC / AC converter. Example 34: The method according to any one of Examples 23 to 33, wherein the calibration process is performed in response to the detection of the end of a predetermined period of the preheating process. Example 35: The method according to any one of Examples 23 to 33, wherein the preheating process is performed in response to detection of user input. Example 36: The method according to Example 35, wherein user input corresponds to user activation of the aerosol generator. Example 37: The method according to any one of Examples 23 to 33, wherein the aerosol generator is configured to removably receive an aerosol generating article, the aerosol generating article comprises a susceptor and an aerosol forming substrate, and a preheating process is performed in response to the detection of the presence of the aerosol generating article in the aerosol generator. Example 38: The method according to any one of Examples 23 to 37, wherein the predetermined period is 10 to 15 seconds. Example 39: The method according to any one of Examples 1 to 38, further comprising controlling the power supplied to the induction heating device during the second heating stage to progressively increase the target operating value from a first target operating value associated with the first operating temperature of the susceptor to a second target operating value associated with the second operating temperature of the susceptor. Example 40: The method according to Example 39, wherein the first operating temperature is sufficient for the aerosol-forming substrate to form an aerosol. Example 41: The method according to Example 40, wherein the first operating temperature is 150°C to 330°C, the second operating temperature is 200°C to 400°C, and the temperature difference between the first and second operating temperatures is at least 30°C. Example 42: The method according to any one of Examples 39 to 41, wherein the stepwise increase of the target operating value includes at least three consecutive steps, each having a predetermined duration. Example 43: The method according to Example 42, further comprising controlling the power supplied to the induction heating device to maintain a target operating value of the induction heating device at a value associated with each step for the duration of each step. Example 44: The method according to Example 43, wherein maintaining a target operating value for an induction heating device includes determining one of a current value, a conductance value, and a resistance value associated with a susceptor, and adjusting the power supplied to the induction heating device based on the determined value. Example 45: The method according to any one of Examples 39 to 44, wherein the duration of the step is at least 10 seconds. Example 46: The method according to any of Examples 39 to 44, wherein the duration of the step is 30 to 200 seconds. Example 47: The method according to any of Examples 39 to 44, wherein the duration of the step is 40 to 160 seconds. Example 48. The method according to any of Examples 39 to 47, wherein the duration of each step is predetermined. Example 49: The method according to any one of Examples 39 to 44, wherein the duration of the step corresponds to a predetermined number of user smoke inhalations. Example 50: The method according to any one of Examples 39 to 44, wherein the first step of a series of steps has a longer duration than the subsequent steps. Example 51: The method according to any one of Examples 1 to 49, wherein the induction heating device includes a DC / AC converter and an inductor connected to the DC / AC converter. Example 52: The method according to Embodiment 51, wherein power from a power source is continuously supplied to an inductor via a DC / AC converter. Example 53: The method according to Embodiment 51 or 52, wherein power from a power source is supplied to an inductor as multiple pulses via a DC / AC converter, and each pulse is separated at a time interval. Example 54: The method according to Example 53, wherein controlling the power supplied to the induction heating device includes controlling the time interval between each of a plurality of pulses. Example 55: The method according to Example 53, wherein controlling the power supplied to the induction heating device includes controlling the length of each pulse of a plurality of pulses. Example 56: The method according to any one of Examples 1 to 55, wherein the first calibration temperature is 150°C to 350°C, the second calibration temperature is 200°C to 400°C, and the temperature difference between the first calibration temperature and the second calibration temperature is at least 50°C. Example 57: Aerosol generator comprising: a power supply for providing a DC supply voltage and DC current; a power supply electronic circuit connected to the power supply, the power supply electronic circuit including a DC / AC converter and an inductor connected to the DC / AC converter for generating an alternating magnetic field, wherein the inductor is capable of coupling with a susceptor when energized by the alternating current from the DC / AC converter, and the susceptor is configured to heat an aerosol-forming substrate; and a controller configured to control the power supplied to the power supply electronic circuit so as to maintain a target operating value of the power supply electronic circuit within the first and second calibration values ​​during a second heating phase during user operation of the aerosol generator for generating an aerosol, wherein the first calibration value is associated with a first calibration temperature of the susceptor, and the second calibration value is associated with a second calibration temperature of the susceptor, during a second heating phase during user operation of the aerosol generator for generating an aerosol. Example 58: The aerosol generator according to Example 57, wherein power from a power source is continuously supplied to an inductor via a DC / AC converter. Example 59: The aerosol generator according to Examples 57-58, wherein the second calibration temperature of the susceptor corresponds to the Curie temperature of the susceptor material. Example 60: The aerosol generator according to Example 59, wherein the first calibration temperature of the susceptor corresponds to the temperature at which the susceptor material has maximum permeability. Example 61: An aerosol generator according to any one of Examples 57 to 60, wherein the first calibration value is the first conductance value, the second calibration value is the second conductance value, and the target operating value is the target conductance value. Example 62: The aerosol generator according to Example 61, wherein the calibration process includes (i) controlling the power supplied to the power supply electronic circuit to raise the temperature of the susceptor; (ii) monitoring the conductance value associated with the susceptor; (iii) interrupting the power supply to the power supply electronic circuit when the conductance value reaches a maximum value, wherein the conductance value at the maximum value corresponds to a second calibration value; and (iv) monitoring the conductance value until the conductance value reaches a minimum value, wherein the conductance value at the minimum value corresponds to a first calibration value. Example 63: The aerosol generator according to Example 62, wherein monitoring the conductance value includes measuring the DC current drawn from the power supply at the input side of the DC / AC converter. Example 64: The aerosol generator according to Example 63, further comprising monitoring the conductance value at the input side of a DC / AC converter and measuring the DC voltage at the power supply. Example 65: The aerosol generator according to any one of Examples 62 to 65, further comprising repeating steps (i) to (iv) in response to determining that the calibration process has reached a minimum value. Example 66: The aerosol generator according to Example 65, wherein the first calibration value and the second calibration value correspond to conductance values ​​measured during at least the first iteration of steps (i) to (iv). Example 67: An aerosol generator according to any one of Examples 57 to 60, wherein the first calibration value is the first resistance value, the second calibration value is the second resistance value, and the target operating value is the target resistance value. Example 68: The aerosol generator according to Example 67, wherein the calibration process includes: i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; ii) monitoring the resistance value associated with the susceptor; iii) interrupting the power supply to the induction heating device when the resistance value reaches a minimum value, wherein the resistance value at the minimum value corresponds to a second calibration value; and iv) monitoring the resistance value until the resistance value reaches a maximum value, wherein the resistance value at the maximum value corresponds to a first calibration value. Example 69: The aerosol generator according to Example 68, wherein monitoring the resistance value includes measuring the DC current drawn from the power supply at the input side of the DC / AC converter. Example 70: The aerosol generator according to Example 69, further comprising monitoring the resistance value at the input side of a DC / AC converter and measuring the DC voltage at the power supply. Example 71: The aerosol generator according to any one of Examples 68 to 70, further comprising repeating steps i) to iv) in response to determining that the calibration process has reached its maximum value. Example 72: The aerosol generator according to Example 71, wherein the first calibration value and the second calibration value correspond to resistance values ​​measured during at least the first iteration of steps i) to iv). Example 73: An aerosol generator according to any one of Examples 57 to 60, wherein the first calibration value is the first current value, the second calibration value is the second current value, and the target operating value is the target current value. Example 74: The aerosol generator according to Example 73, wherein the calibration process includes: i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; ii) monitoring the current value associated with the susceptor; iii) interrupting the power supply to the induction heating device when the current value reaches a maximum value, wherein the current value at the maximum value corresponds to a second calibration value; and iv) monitoring the conductance value until the conductance value reaches a minimum value, wherein the current value at the minimum value corresponds to a first calibration value. Example 75: The aerosol generator according to Example 74, wherein monitoring the current value includes measuring the DC current drawn from the power supply at the input side of the DC / AC converter. Example 76: The aerosol generator according to Example 75, further comprising monitoring the current value at the input side of a DC / AC converter and measuring the DC voltage at the power supply. Example 77: The aerosol generator according to any one of Examples 74 to 76, further comprising repeating steps i) to iv) in response to determining that the calibration process has reached a minimum value. Example 78: The aerosol generator according to Example 77, wherein the first calibration value and the second calibration value correspond to current values ​​measured during at least the first iteration of steps i) to iv). Example 79: The aerosol generator according to any one of Examples 57 to 78, further configured to perform a calibration process in response to detecting one or more of a predetermined period, a predetermined number of user smoke inhalations, and a predetermined voltage value of the power supply during a second heating stage. Example 80: The aerosol generator according to any of Examples 57 to 79, wherein the controller is further configured to perform a preheating process during a first heating stage, and the controller is configured to perform a preheating process before a calibration process, and the preheating process has a predetermined duration. Example 81: The aerosol generator according to Example 80, wherein the preheating process includes (i) controlling the power supplied to the power supply electronic circuit to raise the temperature of the susceptor, (ii) monitoring the conductance value associated with the susceptor with the power supply, and (iii) interrupting the power supply to the power supply electronic circuit when the conductance value reaches a minimum value. Example 82: The aerosol generator according to Example 81, wherein the controller is further configured to repeat steps i) to iii) of the preheating process until the end of the predetermined period of the preheating process if the conductance value reaches a minimum value before the end of the predetermined period of the preheating process. Example 83: The aerosol generator according to Example 81 or 82, further configured to generate a control signal that stops the operation of the aerosol generator if the conductance value of the susceptor does not reach a minimum value during a predetermined period of the preheating process. Example 84: The aerosol generator according to Example 80, wherein the preheating process includes the steps of i) controlling the power supplied to an induction heating device to raise the temperature of the susceptor, ii) monitoring the resistance value associated with the susceptor with the power supply, and iii) interrupting the power supply to the susceptor when the resistance value reaches its maximum value. Example 85: The aerosol generator according to Example 84, further configured so that if the resistance value reaches its maximum value before the end of a predetermined period of the preheating process, steps (i) to (iii) of the preheating process are repeated until the end of a predetermined period of the preheating process. Example 86: The aerosol generator according to Example 84, further configured to generate a control signal that stops the operation of the aerosol generator if the resistance value associated with the susceptor does not reach a maximum value during a predetermined period of the preheating process. Example 87: The aerosol generator according to Example 80, wherein the preheating process includes the steps of i) controlling the power supplied to an induction heating device to raise the temperature of the susceptor, ii) monitoring the current value associated with the susceptor at the power supply, and iii) interrupting the power supply to the susceptor when the current value reaches a minimum value. Example 88: The aerosol generator according to Example 87, further configured such that if the current value reaches a minimum value before the end of a predetermined period of the preheating process, steps (i) to (iii) of the preheating process are repeated until the end of a predetermined period of the preheating process. Example 89: The aerosol generator according to Example 87, further configured to generate a control signal that stops the operation of the aerosol generator if the current value associated with the susceptor does not reach a minimum value during a predetermined period of the preheating process. Example 90: An aerosol generator according to any one of Examples 80 to 89, wherein during the preheating process, power from a power supply is continuously supplied to the inductor via a DC / AC converter. Example 91: An aerosol generator according to any one of Examples 80 to 90, wherein the controller is configured to perform a calibration process in response to detecting the end of a predetermined period of the preheating process. Example 92: An aerosol generator according to any one of Examples 80 to 91, wherein the controller is configured to perform a preheating process in response to detecting user input. Example 93: The aerosol generator according to Example 92, wherein user input corresponds to user activation of the aerosol generator. Example 94: An aerosol generator according to any one of Examples 80 to 91, wherein the controller is configured to perform a preheating process in response to detecting the presence of an aerosol-generating article within a predetermined threshold distance of an inductor. Example 95: An aerosol generator according to any one of Examples 80 to 94, wherein the predetermined period is 10 to 15 seconds. Example 96: The aerosol generator according to any one of Examples 57 to 95, further comprising controlling the power supplied to the power supply electronic circuit during the second heating stage to progressively increase the target operating value from a first target operating value associated with a first operating temperature to a second target operating value associated with a second operating temperature. Example 97: The aerosol generator according to Example 96, wherein the first operating temperature is sufficient for the aerosol-forming substrate to form an aerosol. Example 98: The aerosol generator according to Example 97, wherein the first operating temperature is 150°C to 330°C, the second operating temperature is 200°C to 400°C, and the temperature difference between the first and second operating temperatures is at least 30°C. Example 99: An aerosol generator according to any one of Examples 96 to 98, wherein the stepwise increase of the target operating value includes at least three consecutive steps, each step having a duration. Example 100: The aerosol generator according to Example 99, further comprising controlling the power supplied to the power supply electronic circuit, for each step, maintaining a target operating value of the power supply electronic circuit at a value associated with each step for the duration of each step. Example 101: An aerosol generator according to Example 100, wherein maintaining a target operating value of the power supply electronics includes determining one of a current value, a conductance value, and a resistance value associated with a susceptor, and adjusting the power supplied to the power supply electronics based on the determined value. Example 102: The aerosol generator according to Example 101, further comprising a power supply electronic circuit that includes a current sensor configured to measure the DC current drawn from the power supply at the input side of a DC / AC converter. Example 103: The aerosol generator according to Example 102, further comprising a voltage sensor configured to measure the DC supply voltage of the power supply at the input side of a DC / AC converter. Example 104: An aerosol generator according to any one of Examples 100 to 104, wherein the duration of the step is at least 10 seconds. Example 105: An aerosol generator according to any one of Examples 100 to 104, wherein the duration of the step is 30 to 200 seconds. Example 106: An aerosol generator according to any one of Examples 100 to 103, wherein the duration of the step is 40 seconds to 160 seconds. Example 107: An aerosol generator according to any of Examples 100 to 106, wherein the duration of each step is predetermined. Example 108: An aerosol generator according to any one of Examples 100 to 103, wherein the duration of the step corresponds to a predetermined number of user smoke inhalation. Example 109: An aerosol generator according to any one of Examples 100 to 106, wherein the first step of a series of steps has a longer duration than the subsequent steps. Example 110: An aerosol generator according to any of Examples 57 to 106, wherein power from a power source is supplied to an inductor as multiple pulses via a DC / AC converter, and each pulse is separated at a time interval. Example 111: The aerosol generator according to Example 110, wherein controlling the power supplied to the power supply electronic circuit includes controlling the time interval between each of a plurality of pulses. Example 112: The aerosol generator according to Example 110, wherein controlling the power supplied to the power supply electronic circuit includes controlling the length of each pulse of a plurality of pulses. Example 113: An aerosol generator according to any one of Examples 57 to 111, wherein the first calibration temperature is 150°C to 300°C, the second calibration temperature is 200°C to 400°C, and the temperature difference between the first calibration temperature and the second calibration temperature is at least 50°C. Example 114: An aerosol generator according to any one of Examples 57 to 113, wherein the power supply electronic circuit further includes a matching network for matching the impedance of the inductor with the impedance of the susceptor. Example 115: An aerosol generator according to any one of Examples 57 to 114, 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 116: An aerosol generating system comprising an aerosol generating device and an aerosol generating article described in any of Examples 56 to 15, wherein the aerosol generating article comprises an aerosol forming substrate and a susceptor. Example 117: The aerosol generating system according to Example 116, wherein the susceptor comprises a first layer made of a first material and a second layer made of a second material, and the first material is positioned in physical contact with the second material. Example 118: The aerosol generating system according to Example 117, wherein the first material is one of aluminum, iron, and stainless steel, and the second material is nickel or a nickel alloy. Example 119: The aerosol generating system according to Example 117 or 118, wherein the first material has a first Curie temperature, the second material has a second Curie temperature, and the second Curie temperature is lower than the first Curie temperature. Example 120: The aerosol generation system according to Example 119, wherein the second calibration temperature corresponds to the second Curie temperature of the second susceptor material.

[0102] Here, we will further describe the embodiments with reference to the figures. [Brief explanation of the drawing]

[0103] [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 that engages 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 of the LC load network of the induction heating apparatus 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]

[0104] 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 located 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 located along the radial central axis of the aerosol forming substrate 110.

[0105] The susceptor 160 comprises at least two different materials. The susceptor 160 is preferably in the form of an elongated strip 12 mm long and 4 mm wide. The susceptor 160 comprises at least two layers, namely, a first layer of the first susceptor material that is physically in contact with a 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 can be formed by covering a strip of the first susceptor material with a strip of the second susceptor material.

[0106] The aerosol generating article 100 has a proximal end or an oral end 170, which the user inserts into their mouth during use, and a distal end 180 located on the opposite end of the aerosol generating article 100 from the oral end 170. The total length of the assembled aerosol generating article 100 is preferably about 45 mm and the diameter is about 7.2 mm.

[0107] In use, air is drawn by the user through the aerosol generating article 100 from the distal end 180 to the oral 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 oral end 170 of the aerosol generating article 100 may also be described as the downstream end of the aerosol generating article 100. Elements of the aerosol generating article 100 located between the oral end 170 and the distal end 180 can be described as being upstream of the oral end 170, or alternatively 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.

[0108] The support element 120 is located immediately downstream of the aerosol-forming substrate 110 and is in contact with the aerosol-forming substrate 110. The support element 120 may be a hollow cellulose acetate tube. The support element 120 positions the aerosol-forming substrate 110 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.

[0109] The aerosol cooling element 130 is located immediately downstream of the support element 120 and is 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 aggregate of crimped sheets of polylactic acid surrounded by a wrapper 190. The aggregate of crimped sheets of polylactic acid defines a plurality of longitudinal channels extending along the length of the aerosol cooling element 130.

[0110] The mouthpiece 140 is located immediately downstream of the aerosol cooling element 130 and is in contact with the aerosol cooling element 130. The mouthpiece 140 contains a conventional cellulose acetate tow filter with low filtration efficiency.

[0111] To assemble the aerosol-generating article 100, the four elements 110, 120, 130, and 140 described above are aligned and tightly rolled within an 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.

[0112] The aerosol generating article 100 shown in Figure 1 is designed to generate an aerosol in conjunction with an aerosol generating device, such as the aerosol generating device 200 shown in Figure 2A. The aerosol generating device 200 includes a housing 210 having a cavity 220 configured to receive the aerosol generating article 100. The aerosol generating device 200 further includes an induction heating device 230 configured to heat the aerosol generating article 100 for generating an aerosol. Figure 2B shows the aerosol generating device 200 with the aerosol generating article 100 inserted into the cavity 220.

[0113] The induction heating device 230 is shown as a block diagram in Figure 3. The induction heating device 230 comprises a DC power supply 310 and a heating device 320 (also called the power supply electronic circuit). The heating device includes a controller 330, a DC / AC converter 340, a matching network 350, and an inductor 240.

[0114] The DC power supply 310 is configured to supply DC power to the heating device 320. Specifically, the DC power supply 310 has a DC supply voltage (V DC ) and DC current (I DCThe 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 a time period that is a multiple of six minutes. In another example, the power supply 310 may have sufficient capacity to enable a predetermined number of fumigation or discontinuous startups of the heating device.

[0115] The DC / AC converter 340 is configured to supply the inductor 240 with a high-frequency alternating current. 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).

[0116] Figure 4 schematically shows the electrical components of the induction heating device 230, in particular the DC / AC converter 340. The DC / AC converter 340 preferably includes a Class E power amplifier. The Class E power amplifier includes a field-effect transistor 420, a transistor switch 410 including, for example, a metal-oxide-semiconductor field-effect transistor, a transistor switch supply circuit indicated by arrow 430 for supplying a switching signal (gate-source voltage) to the field-effect transistor 420, 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, a DC power supply 310 with a choke L1 draws a DC current I from the DC power supply 310 during operation. DC Along with, DC supply voltage V DC It is shown to supply the ohm resistance R of the inductor L2. Coil And the ohm resistance R of the susceptor 160 Load The ohm resistance R, which represents the sum of these values ​​and a total ohm load of 450, is shown in detail in Figure 5.

[0117] Although the DC / AC converter 340 is shown as including a Class E power amplifier, it should be understood that the DC / AC converter 340 may 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 having four switching transistors acting in pairs.

[0118] Returning to Figure 3, the inductor 240 may receive AC current from the DC / AC converter 340 via a matching network 350 for optimal suitability to the load, although the matching network 350 is not mandatory. The matching network 350 may comprise a small matching transformer. The matching network 350 can improve the power transfer efficiency between the DC / AC converter 340 and the inductor 240.

[0119] As shown in FIG. 2A, the inductor 240 is positioned adjacent to the distal portion 225 of the cavity 220 of the aerosol generating device 200. Thus, during operation of the aerosol generating device 200, the high-frequency alternating current supplied to the inductor 240 causes the inductor 240 to generate a high-frequency alternating magnetic field within the distal portion 225 of the aerosol generating device 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 FIG. 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 such that the susceptor 160 of the aerosol generating article 100 is located within this alternating magnetic field. When the alternating magnetic field penetrates the susceptor 160, the alternating magnetic field causes heating of the susceptor 160. For example, eddy currents are generated within the susceptor 160 which is consequently heated. Further heating is provided by magnetic hysteresis losses 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.

[0120] <� 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 device 320 in order to control the temperature of the susceptor 160.

[0121] FIG. 6 shows the relationship over time of the DC current I drawn from the power supply 310 as the temperature of the susceptor 160 (shown by the dashed line) increases. The DC current I drawn from the power supply 310 DC is measured at the input side of the DC / AC converter 340. For the purposes of this figure, the voltage V of the power supply 310 DC may be assumed to be substantially constant. When the susceptor 160 is inductively heated, the apparent resistance of the susceptor 160 increases. This increase in resistance results in a decrease in the DC current I drawn from the power supply 310 DC is substantially constant. When the susceptor 160 is inductively heated, the apparent resistance of the susceptor 160 increases. This increase in resistance results in a decrease in the DC current I drawn from the power supply 310DC Observed as a decrease, at a constant voltage, it decreases as the temperature of susceptor 160 rises. The high-frequency alternating magnetic field provided by inductor 240 induces eddy currents near the susceptor surface, an effect known as the skin effect. The resistance of susceptor 160 depends partly on the electrical resistivity of the first susceptor material, partly on the resistivity of the second susceptor material, and partly on the depth of the skin layer of each material available for the induced eddy currents, with the resistivity being temperature-dependent. When the second susceptor material reaches its Curie temperature, it loses its magnetism. This increases the amount of skin layer available for eddy currents within the second susceptor material, thereby decreasing the apparent resistance of susceptor 160. As a result, the skin depth of the second susceptor material begins to increase and the resistance begins to decrease, the detected DC current I DC A temporary increase occurs. This is considered a trough (local minimum) in Figure 6. The current continues to increase until it reaches the maximum skin depth that coincides with the point at which the second susceptor material loses its innate magnetic properties. This point is called the Curie temperature and is considered a hill (local maximum) in Figure 6. At this point, the second susceptor material has undergone a phase transition 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 material-specific temperature). If the inductor 240 continues to generate an alternating magnetic field after reaching the Curie temperature (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, thereby continuing Joule heating of the susceptor 160, which causes the resistance to increase again (the resistance has a polynomial dependence on temperature, and for most metal susceptor materials, it can be approximated as a cubic polynomial dependence for the inventors' purposes), and the current begins to decrease again as long as the inductor 240 continues to supply power to the susceptor 160.

[0122] Therefore, as can be seen from Figure 6, the apparent resistance of the susceptor 160 (and the current I drawn from the corresponding power supply 310) DCThe apparent resistance (I) can vary with respect to the temperature of the susceptor 160, which has a strictly monotonic relationship over a specific temperature range of the susceptor 160. This strictly monotonic relationship allows for a clear determination of 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 one 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 allows for 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.

[0123] At least the DC current I drawn from power supply 310 DC This 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 device 320 based on the conductance value or resistance value. Conductance is the DC current I DC DC supply voltage V DC Resistance is defined as a ratio to the DC supply voltage V DC DC current I DC It is defined as a ratio to . The heating device 320 uses DC current I DC The heating device may be equipped with a current sensor (not shown) for measuring the DC supply voltage V DC A voltage sensor (not shown) for measuring the current may optionally be included. 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].

[0124] 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 may maintain the measured conductance value or measured resistance value at the target value using any suitable control loop, for example, by using a proportional-integral-derivative control loop.

[0125] 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 an aerosol, the conductance value or resistance value associated with the susceptor and measured on 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 hill in the current plot in Figure 6). The first calibration temperature is a temperature above the susceptor temperature at which the skin depth of the second susceptor material begins to increase (resulting in a temporary decrease in resistance). Thus, the first calibration temperature is a temperature above the temperature at which the second susceptor material has maximum permeability. The first calibration temperature is at least 50 degrees Celsius lower than the second calibration temperature. At least the second calibration value may be determined by calibration of 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.

[0126] Because conductance (resistance) has a polynomial dependence on temperature, it behaves nonlinearly as a function of temperature. However, the first and second calibration values ​​are chosen such that the difference between them is small, and since the first and second calibration values ​​are at the top of the operating temperature range, this dependence can be approximated as linear between the first and second calibration values. Therefore, to adjust the temperature to the target operating temperature, the conductance is adjusted according to the first and second calibration values ​​via 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 may be given as follows: G Target =G Lower +(x×ΔG) In the formula, ΔG is the difference between the first conductance value and the second conductance value, and x is the ratio of ΔG.

[0127] The controller 330 may control the power supply to the heating device 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 DCThe conductance may preferably be measured every 1 millisecond for 100 milliseconds. If the controller 330 monitors the conductance, the load cycle of the switching transistor 410 is reduced when the conductance reaches or exceeds a value corresponding to the target operating temperature. If the controller 330 monitors the resistance, the load cycle of the switching transistor 410 is reduced when the resistance reaches or falls below a value corresponding to the target operating temperature. For example, the load cycle of the switching transistor 410 may be reduced to about 9%. In other words, the switching transistor 410 may switch to a mode in which it generates pulses only every 10 milliseconds for a period 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), it indicates that the temperature of susceptor 160 is below the target operating temperature, and the gate of transistor 410 is again supplied with a train of pulses at the system's selected drive frequency.

[0128] Power may be supplied to the inductor 240 by the controller 330 in the form of a continuous series of pulses of current. In particular, power may be supplied to the inductor 240 in a series of pulses, each separated by a time interval. The continuous series of pulses may include two or more heating pulses and one or more probing pulses between the continuous heating pulses. The heating pulses have an intensity such as heating the susceptor 160. The probing pulses are separated power pulses that do not heat the susceptor 160, but rather obtain feedback regarding the conductance value or resistance value, and then the evolution (decrease) of the susceptor temperature. The controller 330 may control the power by controlling the duration of the time interval 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.

[0129] 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.

[0130] During the calibration process, the controller 330 controls the DC / AC converter 340 to continuously or continuously 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, in some cases, the 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 reaches a first turning point and then decreases until the current increases. This first turning point corresponds to the local minimum conductance value (local maximum resistance value). The controller 330 may record the local minimum of conductance (or local maximum of resistance) as a first calibration value. The controller may record the conductance or resistance value at a predetermined time after the minimum current is reached as a first calibration value. 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 power supply 310, such as 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°C and 350°C. More preferably, if the aerosol-forming substrate 110 contains tobacco, the first calibration temperature is 320°C. The first calibration temperature is at least 50°C lower than the second calibration temperature.

[0131] As the controller 330 continues to control the power supplied to the inductor 240 by the DC / AC converter 340, the measured current increases until a maximum current (corresponding to the Curie temperature of the second susceptor material) is observed, reaching a second turning point before the measured current begins to decrease. 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 power supply to the inductor 240, resulting in a decrease in the temperature of the susceptor 160 and a corresponding decrease in conductance.

[0132] 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 power supply to the inductor 240, the controller 330 continues to monitor the conductance (or resistance) until a third transition point corresponding to the 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 the 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 fourth transition point as the second calibration value. Repeated measurements of the transition points corresponding to the minimum and maximum measurement currents significantly improve subsequent temperature control during user operation of the apparatus for generating aerosols. 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 requires more time for the heat to dissipate within the aerosol-forming substrate 110 and the susceptor 160.

[0133] 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 under similar conditions, the calibration may be performed before heat has spread within the aerosol-forming substrate 110, which may reduce the reliability of the calibration values. If the aerosol-forming substrate 110 is wet, the susceptor 160 will take longer to reach the valley temperature (depending on the moisture content of the substrate 110).

[0134] 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 power supply 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 this point, the controller controls the DC / AC converter 340 to interrupt the power supply to the inductor 240 again. The controller 330 again waits for the same predetermined time to allow the susceptor 160 to cool before continuing heating. This heating and cooling of the susceptor 160 is repeated over a predetermined period of the preheating process. The predetermined period of the preheating process is preferably 11 seconds. Following a predetermined combined period of the preheating process, the calibration process is preferably 20 seconds long.

[0135] If the aerosol-forming substrate 110 is dry, the first minimum value of the preheating process is reached within a predetermined time, and the power interruption is repeated until the end of the predetermined time. If the aerosol-forming substrate 110 is wet, the first minimum value of the preheating process is reached towards the end of the predetermined time. Therefore, performing the preheating process for a predetermined period ensures that the substrate 110 has enough time to reach its lowest temperature in order to be ready to receive continuous power and reach the first maximum value, regardless of the physical state of the substrate 110. This allows for calibration as early as possible without the risk that the substrate 110 has not reached a valley beforehand.

[0136] Furthermore, the aerosol generating article 100 may be configured such that the minimum value is always achieved within a predetermined period of the preheating process. If the minimum value is not reached within a predetermined period 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 include 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 with the heating device 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.

[0137] The preheating process may be performed in response to the reception of user input, such as 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.

[0138] Figure 7 is a graph of conductance against time showing the heating profile of the susceptor 160. The graph shows two consecutive stages of heating: a first heating stage 710, which includes the preheating process 710A and calibration process 710B described above, and a second heating stage 720, which corresponds to user operation of the aerosol generator 200 that generates the aerosol. Although Figure 7 is shown as a graph of conductance against time, it should be 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.

[0139] 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 a determined resistance value associated with the susceptor, it should be understood that the above techniques can also be implemented based on a current value measured at the input of the DC / AC converter 340.

[0140] 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 lowest temperature at which the aerosol-forming substrate forms 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 highest temperature at which it is desirable to heat the aerosol-forming substrate 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 valley of the current plot shown in Figure 6. The first operating temperature may be between 150°C and 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, and as a result, an aerosol is formed between each temperature step.

[0141] The number of temperature steps shown in Figure 7 is illustrative, and it should be understood that 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. The duration of the first temperature step is preferably 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, more preferably 40 to 160 seconds. The duration of each temperature step may correspond to a predetermined number of user smoke inhalations. Preferably, the first temperature step corresponds to four user smoke inhalations, and each subsequent temperature step corresponds to one user smoke inhalation.

[0142] During each temperature step, the temperature of the susceptor 160 is maintained at the target operating temperature corresponding to that temperature step. Therefore, during each temperature step, the controller 330 controls the power supply to the heating device 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.

[0143] As an example, the second heating stage 720 consists of the following five temperature steps, a duration of 160 seconds, and G Target =G Lower A first temperature step with a target conductance value of +(0.09 × ΔG), a duration of 40 seconds, and G Target =G Lower A second temperature step with a target conductance value of +(0.25×ΔG), a duration of 40 seconds, and G Target =G Lower A third temperature step with a target conductance value of +(0.4×ΔG), a duration of 40 seconds, and G Target =G Lower A fourth temperature step having a target conductance value of +(0.56×ΔG), as well as a period of 85 seconds and G Target =G LowerA fifth temperature step having a target conductance value of +(0.75 × ΔG) may be included. These temperature steps may correspond to temperatures of 330 degrees Celsius, 340 degrees Celsius, 345 degrees Celsius, 355 degrees Celsius, and 380 degrees Celsius.

[0144] Figure 8 is a flowchart of method 800 for controlling aerosol generation in the aerosol generator 200. As described above, the controller 330 may be programmed to implement method 800.

[0145] The method begins in step 810, where 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, such as 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.

[0146] In response to detecting user operation in step 810, the controller 330 may be configured to perform any of the preheating processes described above. At the end of a predetermined period 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 calibration process is complete, the controller 330 performs a second heating step in step 840 in which an aerosol is generated.

[0147] 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 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 generator comprises an induction heating device and a power supply for supplying power to the induction heating device, and the method is During a first heating phase of user operation of the aerosol generator for generating an aerosol, a calibration process is performed to define a first calibration value and a second calibration value for the induction heater, wherein the first calibration value is associated with a first calibration temperature of a susceptor inductively coupled to the induction heater, the second calibration value is associated with a second calibration temperature of the susceptor, and the susceptor is configured to heat the aerosol-forming substrate. This includes controlling the power supplied to the induction heating device during the second heating phase of the user operation of the aerosol generator to maintain the target operating value of the induction heating device within the first and second calibration values, Performing the calibration process includes: (i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; (ii) monitoring a value associated with the current associated with the susceptor; (iii) interrupting the power supply to the induction heating device when the value reaches a first extreme value, wherein the value associated with the current at the first extreme value corresponds to the second calibration value; and (iv) monitoring the value until the value reaches a second extreme value, wherein the value associated with the current at the second extreme value corresponds to the first calibration value. A method comprising performing the calibration process, further comprising repeating steps (i) to (iv) in response to determining that the value associated with the current has reached the second extreme value, wherein the first calibration value and the second calibration value correspond to values ​​associated with the current measured during at least a first iteration of steps (i) to (iv).

2. The method according to claim 1, wherein the first calibration value is a first conductance value, the second calibration value is a second conductance value, and the target operating value is a target conductance value.

3. The method according to claim 2, wherein step (ii) of the calibration process includes monitoring a conductance value associated with the susceptor, step (iii) of the calibration process includes interrupting the power supply to the induction heating device when the conductance value reaches a maximum value, the conductance value at the maximum value corresponding to the second calibration value, and step (iv) of the calibration process includes monitoring the conductance value until the conductance value reaches a minimum value, the conductance value at the minimum value corresponding to the first calibration value.

4. The method according to claim 3, wherein monitoring the conductance value includes measuring the DC current drawn from the power supply at the input side of the DC / AC converter.

5. The method according to claims 1 to 4, further comprising performing a preheating process during the first heating step, wherein the preheating process is performed before the calibration process and the preheating process has a predetermined duration.

6. The method according to claim 5, wherein the preheating process includes (i) controlling the power supplied to the induction heating device to raise the temperature of the susceptor; (ii) monitoring a current value associated with the susceptor with the power supply; and (iii) interrupting the power supply to the susceptor when the current value reaches a minimum value.

7. The method according to claim 6, further comprising repeating steps (i) to (iii) of the preheating process until the end of the predetermined period of the preheating process if the current value reaches a minimum value before the end of the predetermined period of the preheating process.

8. The method according to claim 6, further comprising stopping the operation of the aerosol generator if the current value associated with the susceptor does not reach a minimum value during a predetermined period of the preheating process.

9. The method according to any one of claims 5 to 8, wherein the aerosol generator is configured to removably 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 presence of the aerosol generating article in the aerosol generator.

10. The method according to any one of claims 1 to 9, further comprising controlling the power supplied to the induction heating device during the second heating step to control the power supplied to the induction heating device to gradually increase the target operating value from a first target operating value associated with a first operating temperature of the susceptor to a second target operating value associated with a second operating temperature of the susceptor.

11. 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 is DC / AC converter and A power supply electronic circuit including an inductor connected to the DC / AC converter to generate an alternating magnetic field, wherein the inductor is capable of coupling to a susceptor when energized by an alternating current from the DC / AC converter, and the susceptor is configured to heat an aerosol-forming substrate, It is a controller, During a first heating phase of user operation of the aerosol generator for generating aerosols, a calibration process is performed to define a first calibration value and a second calibration value of the power supply electronic circuit, wherein the first calibration value is associated with a first calibration temperature of the susceptor, and the second calibration value is associated with a second calibration temperature of the susceptor, and During a second heating phase of user operation of the aerosol generator for generating aerosols, the power supplied to the power supply electronic circuit is controlled to maintain the target operating value of the power supply electronic circuit within the first and second calibration values. Performing the calibration process includes: (i) controlling the power supplied to the power supply electronic circuit to raise the temperature of the susceptor; (ii) monitoring a value associated with the current associated with the susceptor; (iii) interrupting the power supply to the power supply electronic circuit when the value reaches a first extreme value, wherein the value associated with the current at the first extreme value corresponds to the second calibration value; and (iv) monitoring the value until the value reaches a second extreme value, wherein the value associated with the current at the second extreme value corresponds to the first calibration value. Aerosol generator comprising a controller, wherein performing the calibration process further includes repeating steps (i) to (iv) in response to determining that the value associated with the current has reached a second extreme value, the first calibration value and the second calibration value corresponding to values ​​associated with the current measured during at least a first iteration of steps (i) to (iv).

12. The aerosol generator according to claim 11, wherein the second calibration temperature of the susceptor corresponds to the Curie temperature of the susceptor material.

13. The aerosol generator according to claim 11 or 12, wherein the first calibration value is a first resistance value, the second calibration value is a second resistance value, and the target operating value is a target resistance value.

14. The aerosol generator according to claim 13, wherein step ii) of the calibration process includes monitoring a resistance value associated with the susceptor, step iii) of the calibration process includes interrupting the power supply to the power supply electronic circuit when the resistance value reaches a minimum value, the resistance value at the minimum value corresponds to the second calibration value, and step iv) of the calibration process includes monitoring the resistance value until the resistance value reaches a maximum value, the resistance value at the maximum value corresponds to the first calibration value.

15. The aerosol generator according to any one of claims 11 to 14, wherein power from the power source is supplied to the inductor as a plurality of pulses via the DC / AC converter, and each pulse is separated at a time interval.

16. The aerosol generator according to claim 15, wherein controlling the power supplied to the power supply electronic circuit includes controlling the time interval between each of the plurality of pulses.

17. The aerosol generator according to claim 15, wherein controlling the power supplied to the power supply electronic circuit includes controlling the length of each pulse of the plurality of pulses.

18. An aerosol generating system comprising an aerosol generating device and an aerosol generating article according to any one of claims 11 to 17, wherein the aerosol generating article comprises the aerosol forming substrate and the susceptor.

19. The aerosol generating system according to claim 18, wherein the susceptor comprises a first layer made of a first material and a second layer made of a second material, and the first material is arranged in physical contact with the second material.

20. The aerosol generating system according to claim 19, wherein the first material has a first Curie temperature, and the second material has a second Curie temperature, the second Curie temperature being lower than the first Curie temperature.

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