Aerosol-generating devices and systems including induction heating devices and methods of operation thereof

Abstract

A method for controlling aerosol generation in an aerosol-generating device comprising an induction heating device. The method includes performing a calibration process for measuring one or more calibration values associated with a susceptor, the susceptor inductively coupled to the induction heating device; and controlling power provided to the induction heating device such that a temperature of the susceptor is adjusted based on the one or more calibration values. The method also includes performing a warm-up process prior to the calibration process. The preheating process comprises the steps that power provided for the induction heating device is controlled so that the temperature of the susceptor can be increased; monitoring power supply parameters; and interrupting the supply of power to the induction heating device at a first predetermined value of the monitored power supply parameter.

Description

[0001] The present disclosure relates to an induction heating device for heating an aerosol-forming substrate. The present invention also relates to an aerosol generating device comprising such an induction heating device and a method for controlling aerosol generation in an aerosol generating device.

[0002] An aerosol generating device may comprise an electrically operated heat source configured to heat an aerosol-forming substrate to produce an aerosol. It is important for an aerosol generating device to accurately monitor and control the temperature of the electrically operated heat source to ensure optimal generation and delivery of an aerosol to a user. In particular, it is important to ensure that the electrically operated heat source uniformly heats the aerosol-forming substrate to provide an optimal taste and smell for the user and to prevent the generation of undesirable compounds if a portion of the aerosol-forming substrate is overheated.

[0003] It is desirable to provide temperature monitoring and control of an induction heating device that provides reliable temperature regulation in order to provide uniform heat distribution within the heat source and thereby provide optimal heating of the energy-forming substrate by the aerosol generating device.

[0004] According to one embodiment of the present invention, a method for controlling aerosol generation in an aerosol generating device is provided, the aerosol generating device comprising an induction heating device and a power supply for providing power to the induction heating device. The method comprises: during a user operating the aerosol generating device for generating an aerosol, during a first heating phase, performing a calibration process for measuring one or more calibration values ​​associated with a susceptor, the susceptor being inductively coupled to the induction heating device, wherein the susceptor is configured to heat an aerosol-forming substrate; and during a user operating the aerosol generating device for generating an aerosol, during a second heating phase, controlling the power provided to the induction heating device so that the temperature of the susceptor is adjusted based on the one or more calibration values. The method also comprises performing a preheating process during the first heating phase, wherein the preheating process is performed before the calibration process. The preheating process includes the steps of: i) controlling the power supplied to the induction heating device so that the temperature of the susceptor increases; ii) monitoring a power parameter, wherein the power parameter is at least partially based on the current; and iii) interrupting the supply of power to the induction heating device at a first predetermined value of the monitored power parameter, wherein the first predetermined value of the monitored power parameter is associated with a current value greater than a minimum operating current.

[0005] The preheating process allows heat to diffuse within the aerosol-forming substrate prior to initiating the calibration process so that there is a uniform heat distribution within the susceptor, thereby improving the reliability of the calibration values. Furthermore, the preheating process provides sufficient heating to the susceptor to reduce temperature gradients within the aerosol-forming substrate without increasing the length of time required for preheating. Thus, the preheating process provides improved heating of the aerosol-forming substrate during operation of the aerosol generating device by a user for generating an aerosol, without affecting the user experience.

[0006] At minimum current, the first predetermined value of the monitored power supply parameter may be between 101% and 150% of the power supply parameter value.

[0007] The first predetermined value of the monitored power supply parameter may correspond to a susceptor temperature between 170 degrees Celsius and 270 degrees Celsius, preferably between 170 degrees Celsius and 240 degrees Celsius or between 240 degrees Celsius and 270 degrees Celsius.

[0008] The power supply parameter being monitored can be conductance or resistance.

[0009] The method may further comprise storing at least a first predetermined value of the monitored power supply parameter in a memory of the aerosol generating device.

[0010] Heating to a predefined value reduces the time required for the preheating process and ensures that uniform heating of the aerosol-forming substrate is reliably enabled.

[0011] Monitoring the power supply parameter may include measuring a plurality of values ​​of the power supply parameter. Interrupting the supply of power to the induction heating device at a first predetermined value of the monitored power supply parameter may include determining that a difference between consecutive values ​​of the plurality of values ​​is below a threshold difference.

[0012] After interrupting the supply of power to the induction heating device, the preheating process may further include the following steps: iv) controlling the power supplied to the induction heating device at a second predetermined value of the monitored power parameter so that the temperature of the susceptor increases, wherein the second predetermined value of the monitored power parameter is associated with a current value less than the minimum operating current; and vi) repeating steps i) to iv) for a predetermined duration of the preheating process.

[0013] This provides a more even heat distribution in the susceptor and aerosol-forming substrate during the preheating process.

[0014] The predetermined duration of the heating process may be between 10 and 15 seconds.

[0015] The method may further comprise ceasing operation of the aerosol generating device if the monitored power supply parameter does not reach a value corresponding to a minimum operating current of the susceptor during a predetermined duration of the preheating process.

[0016] The susceptor is preferably included in an aerosol-generating article that is configured to be inserted into an aerosol-generating device. Aerosol-generating articles that are not configured for use with an aerosol-generating device will not exhibit the same behavior as an authorized aerosol-generating article. In particular, for an aerosol-generating article that is not configured for use with an aerosol-generating device, no minimum current / conductance value or maximum resistance value will be observed during the predetermined duration of the preheating process. This therefore prevents the use of unauthorized aerosol-generating articles.

[0017] The second predetermined value of the power parameter may correspond to a susceptor temperature between 110 degrees Celsius and 220 degrees Celsius.

[0018] The preheating process may be performed in response to detecting a user input. The user input may correspond to a user activating the aerosol generating device. The aerosol generating device may comprise a cavity configured to receive an aerosol generating article, wherein the aerosol generating article comprises a susceptor, and wherein the preheating process is performed in response to detecting the aerosol generating article.

[0019] Detecting the aerosol-generating article may comprise a detection receptor.

[0020] The one or more calibration values ​​may include a power supply parameter value corresponding to a minimum operating temperature of the susceptor.

[0021] The one or more calibration values ​​may also include a power supply parameter value corresponding to a maximum operating temperature of the susceptor.

[0022] Controlling power provided to the induction heating device such that the temperature of the susceptor is adjusted based on the one or more calibration values ​​may include maintaining the temperature of the susceptor between a minimum operating temperature of the susceptor and a maximum operating temperature of the susceptor.

[0023] According to one aspect, an aerosol generating device is provided, comprising: a power supply for providing a DC supply voltage and a DC current; and power supply electronics connected to the power supply. The power supply electronics comprises: a DC / AC converter; an inductor connected to the DC / AC converter for generating an alternating magnetic field; and a controller. When excited by the alternating current from the DC / AC converter, the inductor can be coupled to a susceptor, wherein the susceptor is configured to heat an aerosol-forming substrate. The controller can be configured to: during a user operating the aerosol generating device for generating an aerosol, during a first heating phase, perform a calibration process for measuring one or more calibration values ​​associated with the susceptor; and during a user operating the aerosol generating device for generating an aerosol, during a second heating phase, control the power provided to the inductor so that the temperature of the susceptor is adjusted based on the one or more calibration values. During the first heating phase, the controller is further configured to perform a preheating process, wherein the preheating process is performed before the calibration process. The preheating process includes the steps of: i) controlling power supplied to the inductor such that a temperature of the inductor increases; ii) monitoring a power parameter, wherein the power parameter is based at least in part on current; and iii) interrupting the supply of power to the inductor at a first predetermined value of the monitored power parameter, wherein the first predetermined value of the monitored power parameter is associated with a current value greater than a minimum operating current.

[0024] The first predetermined value of the monitored power parameter may be between 101% and 150% of the power parameter value corresponding to the minimum operating current.

[0025] The first predetermined value of the monitored power supply parameter may correspond to a susceptor temperature between 170 degrees Celsius and 270 degrees Celsius, preferably between 170 degrees Celsius and 240 degrees Celsius or between 240 degrees Celsius and 270 degrees Celsius.

[0026] The power supply parameter being monitored can be conductance or resistance.

[0027] The aerosol generating device may further comprise a memory.The memory may be configured to store at least a first predetermined value of a monitored power supply parameter.

[0028] Monitoring the power supply parameter may include measuring a plurality of values ​​of the power supply parameter. Interrupting the provision of power to the inductor at a first predetermined value of the monitored power supply parameter may include determining that a difference between consecutive values ​​of the plurality of values ​​is below a threshold difference.

[0029] After interrupting the supply of power to the power electronics, the preheating process may further include the following steps: iv) at a second predetermined value of the monitored power parameter, controlling the power supplied to the inductor so that the temperature of the susceptor increases, wherein the second predetermined value of the monitored power parameter corresponds to a susceptor temperature less than a minimum operating current; and vi) repeating steps i) to iv) for a predetermined duration of the preheating process.

[0030] The predetermined duration of the heating process may be between 10 and 15 seconds.

[0031] The controller may be further configured to stop operation of the aerosol generating device if the monitored power supply parameter does not reach a value corresponding to a minimum operating current for the susceptor during a predetermined duration of the preheating process.

[0032] The second predetermined value of the monitored power supply parameter may correspond to a susceptor temperature between 110 degrees Celsius and 220 degrees Celsius.

[0033] The controller may be configured to perform a preheating process in response to detecting a user input.

[0034] The user input may correspond to user activation of the aerosol generating device.

[0035] The aerosol generating device may comprise a cavity configured to receive an aerosol generating article. The aerosol generating article may comprise a susceptor. The controller may be configured to perform the preheating process in response to detecting an aerosol generating article. Detecting the aerosol generating article may comprise detecting the susceptor.

[0036] The one or more calibration values ​​may include a power supply parameter value corresponding to a minimum operating temperature of the susceptor.

[0037] The one or more calibration values ​​may also include a power supply parameter value corresponding to a maximum operating temperature of the susceptor.

[0038] Controlling power provided to the induction heating device such that the temperature of the susceptor is adjusted based on the one or more calibration values ​​may include maintaining the temperature of the susceptor between a minimum operating temperature of the susceptor and a maximum operating temperature of the susceptor.

[0039] According to another aspect, there is provided an aerosol generating system comprising the above-mentioned aerosol generating device; and an aerosol generating article, wherein the aerosol generating article comprises an aerosol generating substrate and a susceptor.

[0040] As used herein, the term "aerosol generating device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol generating device may interact with one or both of an aerosol generating article comprising an aerosol-forming substrate or a cartridge comprising an aerosol-forming substrate. In some examples, the aerosol generating device may heat the aerosol-forming substrate to promote release of volatile compounds from the substrate. An electrically operated aerosol generating device may include an atomizer, such as an electric heater, to heat the aerosol-forming substrate to form an aerosol.

[0041] As used herein, the term "aerosol generating system" refers to the combination of an aerosol generating device and an aerosol-forming substrate. When the aerosol-forming substrate forms part of an aerosol-generating article, the aerosol generating system refers to the combination of an aerosol generating device and an aerosol-generating article. In an aerosol generating system, the aerosol-forming substrate and the aerosol generating device cooperate to generate an aerosol.

[0042] As used herein, the term "aerosol-forming substrate" refers to a substrate capable of releasing volatile compounds that can form an aerosol. The volatile compounds can be released by heating or burning the aerosol-forming substrate. As an alternative to heating or burning, in some cases, the volatile compounds can be released by chemical reaction or by mechanical stimulation (such as ultrasound). The aerosol-forming substrate can be solid, or can include solid and liquid components. The aerosol-forming substrate can be part of an aerosol-generating article.

[0043] As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate capable of releasing volatile compounds that can form an aerosol. The aerosol-generating article may be disposable. An aerosol-generating article comprising an aerosol-forming substrate (including tobacco) may be referred to herein as a tobacco rod.

[0044] Aerosol forms substrate and can comprise nicotine.Aerosol forms substrate and can comprise tobacco, for example aerosol forms substrate and can comprise the tobacco-containing material containing volatile tobacco aroma compounds, and this volatile tobacco aroma compounds discharges from aerosol formation substrate when heating.In a preferred embodiment, aerosol forms substrate and can comprise homogenized tobacco material, for example cast leaf tobacco.Aerosol forms substrate and can comprise both solid component and liquid component.Aerosol forms substrate and can comprise tobacco-containing material, and this tobacco-containing material contains the volatile tobacco aroma compounds discharged from substrate when heating.Aerosol forms substrate and can comprise non-tobacco material.Aerosol forms substrate and can also comprise aerosol forming agent.The example of suitable aerosol forming agent is glycerol and propylene glycol.

[0045] As used herein, "aerosol-cooling element" refers to a component of an aerosol-generating article located downstream of an aerosol-forming substrate such that, in use, an aerosol formed by volatile compounds released from the aerosol-forming substrate passes through and is cooled by the aerosol-cooling element before being inhaled by a user. Aerosol-cooling elements have a large surface area but cause a low pressure drop. Filters and other mouthpieces that produce a high pressure drop (e.g., filters formed from fiber bundles) are not considered to be aerosol-cooling elements. Chambers and cavities within aerosol-generating articles are not considered to be aerosol-cooling elements.

[0046] As used herein, the term "mouthpiece" refers to the portion of an aerosol-generating article, an aerosol-generating device or an aerosol-generating system that is placed in the mouth of a user for direct inhalation of an aerosol.

[0047] As used herein, the term "susceptor" refers to an element including a material capable of converting magnetic field energy into heat. When the susceptor is located in an alternating magnetic field, the susceptor is heated. The heating of the susceptor may be the result of at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material.

[0048] As used herein in reference to an aerosol generating device, the terms "upstream" and "front" and "downstream" and "rear" are used to describe the relative position of components or parts of components of an aerosol generating device relative to the direction in which air flows through the aerosol generating device during use. An aerosol generating device according to the present invention comprises a proximal end through which, in use, an aerosol leaves the device. The proximal end of the aerosol generating device may also be referred to as a mouth end or a downstream end. The mouth end is downstream of the distal end. The distal end of the aerosol generating article may also be referred to as an upstream end. Components or parts of components of an aerosol generating device may be described as being upstream or downstream of each other based on their relative position relative to the airflow path of the aerosol generating device.

[0049] As used herein in reference to an aerosol-generating article, the terms "upstream" and "front" and "downstream" and "rear" are used to describe the relative position of a component or portions of a component of an aerosol-generating article relative to the direction in which air flows through the aerosol-generating article during use. An aerosol-generating article according to the present invention comprises a proximal end through which, in use, the aerosol leaves the article. The proximal end of the aerosol-generating article 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 the aerosol-generating article may also be referred to as the upstream end. Components or portions of a component of an aerosol-generating article may be described as being upstream or downstream of each other based on their relative position between the proximal end of the aerosol-generating article and the distal end of the aerosol-generating article. The front of a component or portion of a component of an aerosol-generating article is the portion at the end closest to the upstream end of the aerosol-generating article. The rear of a component or portion of a component of an aerosol-generating article is the portion at the end closest to the downstream end of the aerosol-generating article.

[0050] As used herein, the term "inductive coupling" refers to the heating of a susceptor when penetrated by an alternating magnetic field. The heating may be caused by the generation of eddy currents in the susceptor. The heating may be caused by hysteresis losses.

[0051] As used herein, the term "puff" means the action of a user inhaling an aerosol into their body through their mouth or nose.

[0052] As used herein, the term "temperature detector" refers to a thermocouple, a negative temperature coefficient resistive temperature sensor, or a positive temperature coefficient resistive temperature sensor.

[0053] The present invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment or aspect described herein.

[0054] Example Ex1: A method for controlling aerosol generation in an aerosol generating device, the aerosol generating device comprising an induction heating device and a power supply for providing power to the induction heating device, and the method comprising: during a user operating the aerosol generating device for generating an aerosol, during a first heating phase, performing a calibration process for measuring one or more calibration values ​​associated with a receptor, the receptor being inductively coupled to the induction heating device, wherein the receptor is configured to heat an aerosol-forming substrate; and during a user operating the aerosol generating device for generating an aerosol, during a second heating phase, controlling the power supplied to the receptor. The method further comprises, during the first heating phase, performing a preheating process, wherein the preheating process is performed before the calibration process, and wherein the preheating process comprises the steps of: i) controlling the power provided to the induction heating device so that the temperature of the susceptor increases; ii) monitoring a power supply parameter, wherein the power supply parameter is at least partially based on current; and iii) interrupting the power supply to the induction heating device at a first predetermined value of the monitored power supply parameter, wherein the first predetermined value of the monitored power supply parameter is associated with a current value greater than a minimum operating current.

[0055] Example Ex2: The method according to example Ex1, wherein at the minimum current, the first predetermined value of the monitored power supply parameter is between 101% and 150% of the power supply parameter value.

[0056] Example Ex3: The method of example Ex1 or Ex2, wherein the first predetermined value of the monitored power supply parameter corresponds to a susceptor temperature between 170 degrees Celsius and 270 degrees Celsius.

[0057] Example Ex4: The method according to one of the preceding examples, wherein the monitored power supply parameter is conductance or resistance.

[0058] Example Ex5: The method according to one of the preceding examples, further comprising storing at least the first predetermined value of the monitored power supply parameter in a memory of the aerosol generating device.

[0059] Example Ex6: A method according to one of Examples Ex1 to Ex4, wherein monitoring the power supply parameter includes measuring multiple values ​​of the power supply parameter, and wherein interrupting the supply of power to the induction heating device at a first predetermined value of the monitored power supply parameter includes determining that the difference between consecutive values ​​of the multiple values ​​is lower than a threshold difference.

[0060] Example Ex7: A method according to one of the preceding examples, wherein, after interrupting the supply of power to the induction heating device, the preheating process further comprises the following steps: iv) controlling the power supplied to the induction heating device at a second predetermined value of the monitored power parameter so that the temperature of the receptor increases, wherein the second predetermined value of the monitored power parameter is associated with a current value less than the minimum operating current; and vi) repeating steps i) to iv) within a predetermined duration of the preheating process.

[0061] Example Ex8: The method according to example Ex7, wherein the predetermined duration of the heating process is between 10 seconds and 15 seconds.

[0062] Example Ex9: The method according to example Ex7 or Ex8, further comprising: stopping the operation of the aerosol generating device if the monitored power supply parameter does not reach a value corresponding to the minimum operating current of the susceptor during the predetermined duration of the preheating process.

[0063] Example Ex10: The method of one of Examples Ex7 to Ex9, wherein the second predetermined value of the power supply parameter corresponds to a susceptor temperature between 110 degrees Celsius and 220 degrees Celsius.

[0064] Example Ex11: The method according to one of the preceding examples, wherein the warm-up process is performed in response to detecting a user input.

[0065] Example Ex12: The method according to example Ex11, wherein the user input corresponds to a user activating the aerosol generating device.

[0066] Example Ex13: A method according to one of Examples Ex1 to Ex10, wherein the aerosol generating device comprises a cavity configured to receive the aerosol generating article, wherein the aerosol generating article comprises the receptor, and wherein the preheating process is performed in response to detecting the aerosol generating article.

[0067] Example Ex14: The method according to example Ex13, wherein detecting the aerosol-generating article comprises detecting the receptor.

[0068] Example Ex15: The method according to one of the preceding examples, wherein the one or more calibration values ​​include a power supply parameter value corresponding to a minimum operating temperature of the susceptor.

[0069] Example Ex16: The method of Example Ex15, wherein the one or more calibration values ​​further include a power supply parameter value corresponding to a maximum operating temperature of the susceptor.

[0070] Example Ex17: The method of Example Ex16, wherein controlling the power provided to the induction heating device such that adjusting the temperature of the susceptor based on the one or more calibration values ​​includes maintaining the temperature of the susceptor between a minimum operating temperature of the susceptor and a maximum operating temperature of the susceptor.

[0071] Example Ex18: An aerosol generating device, comprising: a power supply for providing a DC supply voltage and a DC current; a power supply electronic device connected to the power supply, the power supply electronic device comprising: a DC / AC converter; an inductor, the inductor being connected to the DC / AC converter for generating an alternating magnetic field when excited by an alternating current from the DC / AC converter, the inductor being coupleable to a receptor, wherein the receptor is configured to heat an aerosol-forming substrate; and a controller, the controller being configured to: during a first heating phase when a user operates the aerosol generating device for generating an aerosol, perform a calibration process for measuring one or more calibration values ​​associated with the receptor; and during a first heating phase when a user operates the aerosol generating device for generating an aerosol During the generation of the aerosol, during a second heating phase, the power supplied to the inductor is controlled so that the temperature of the inductor is adjusted based on the one or more calibration values; wherein, during the first heating phase, the controller is further configured to perform a preheating process, wherein the preheating process is performed before the calibration process, and wherein the preheating process comprises the following steps: i) controlling the power supplied to the inductor so that the temperature of the inductor increases; ii) monitoring a power supply parameter, wherein the power supply parameter is at least partially based on the current; and iii) interrupting the power supply to the inductor at a first predetermined value of the monitored power supply parameter, wherein the first predetermined value of the monitored power supply parameter is associated with a current value greater than a minimum operating current.

[0072] Example Ex19: An aerosol generating device according to Example Ex18, wherein the first predetermined value of the monitored power supply parameter is between 101% and 150% of the power supply parameter value corresponding to the minimum operating current.

[0073] Example Ex20: An aerosol generating device according to example Ex18 or Ex19, wherein the first predetermined value of the monitored power supply parameter corresponds to a susceptor temperature between 170 degrees Celsius and 270 degrees Celsius.

[0074] Example Ex21: An aerosol generating device according to one of Examples Ex18 to Ex20, wherein the monitored power supply parameter is conductance or resistance.

[0075] Example Ex22: An aerosol generating device according to one of Examples Ex18 to Ex21, wherein the aerosol generating device further comprises a memory, wherein the memory is configured to store at least the first predetermined value of the monitored power supply parameter.

[0076] Example Ex23: An aerosol generating device according to one of Examples Ex18 to Ex20, wherein monitoring the power parameter includes measuring multiple values ​​of the power parameter, and wherein interrupting the supply of power to the sensor at a first predetermined value of the monitored power parameter includes determining that the difference between consecutive values ​​of the multiple values ​​is lower than a threshold difference.

[0077] Example Ex24: An aerosol generating device according to one of Examples Ex18 to Ex23, wherein, after interrupting the supply of power to the power supply electronic device, the preheating process further includes the following steps: iv) controlling the power supplied to the sensor at a second predetermined value of the monitored power parameter so that the temperature of the sensor increases, wherein the second predetermined value of the monitored power parameter corresponds to a sensor temperature less than the minimum operating current; and vi) repeating steps i) to iv) within a predetermined duration of the preheating process.

[0078] Example Ex25: An aerosol generating device according to example Ex24, wherein the predetermined duration of the heating process is between 10 seconds and 15 seconds.

[0079] Example Ex26: An aerosol generating device according to example Ex24 or Ex25, wherein if the monitored power supply parameter does not reach a value corresponding to the minimum operating current of the susceptor during a predetermined duration of the preheating process, the controller is further configured to stop the operation of the aerosol generating device.

[0080] Example Ex27: An aerosol generating device according to one of Examples Ex24 to Ex26, wherein the second predetermined value of the monitored power supply parameter corresponds to a susceptor temperature between 110 degrees Celsius and 220 degrees Celsius.

[0081] Example Ex28: An aerosol generating device according to one of Examples Ex18 to Ex27, wherein the controller is configured to perform the preheating process in response to detecting a user input.

[0082] Example Ex29: An aerosol generating device according to example Ex28, wherein the user input corresponds to a user activating the aerosol generating device.

[0083] Example Ex30: An aerosol generating device according to one of Examples Ex18 to Ex27, wherein the aerosol generating device comprises a cavity configured to receive an aerosol generating article, wherein the aerosol generating article comprises the receptor, and wherein the controller is configured to perform the preheating process in response to detecting the aerosol generating article.

[0084] Example Ex31: An aerosol-generating device according to example Ex30, wherein detecting the aerosol-generating article comprises detecting the receptor.

[0085] Example Ex32: An aerosol generating device according to one of Examples Ex18 to Ex31, wherein the one or more calibration values ​​include a power supply parameter value corresponding to a minimum operating temperature of the susceptor.

[0086] Example Ex33: An aerosol generating device according to Example Ex32, wherein the one or more calibration values ​​further include a power supply parameter value corresponding to a maximum operating temperature of the susceptor.

[0087] Example Ex34: An aerosol generating device according to Example Ex33, wherein controlling the power provided to the induction heating device such that adjusting the temperature of the susceptor based on the one or more calibration values ​​comprises maintaining the temperature of the susceptor between a minimum operating temperature of the susceptor and a maximum operating temperature of the susceptor.

[0088] Example Ex35: An aerosol generating system comprising the aerosol generating device of any one of Examples Ex18 to Ex34; and an aerosol generating article, wherein the aerosol generating article comprises the aerosol generating substrate and the susceptor.

[0089] Several examples will now be further described with reference to the accompanying drawings, in which:

[0090] Figure 1 shows a schematic cross-sectional illustration of an aerosol-generating article;

[0091] Figure 2A Shown for use with Figure 1 A schematic cross-sectional illustration of an aerosol-generating device for use with the aerosol-generating article illustrated in FIG.

[0092] Figure 2B Shown with Figure 1 A schematic cross-sectional illustration of an aerosol generating device engaged with an aerosol generating article illustrated in FIG.

[0093] Figure 3 is a block diagram showing an induction heating device of the aerosol generating device described with respect to FIG. 2 ;

[0094] Figure 4 It shows about Figure 3 A schematic diagram of the electronic components of the described induction heating device;

[0095] Figure 5 About Figure 4 A schematic diagram of an inductor of an LC load network of an induction heating device described;

[0096] Figure 6 is a graph of DC current versus time illustrating a remotely detectable current change that occurs when a susceptor material undergoes a phase change associated with its Curie point;

[0097] Figure 7 shows a conductance curve of a susceptor during operation of an aerosol generating device;

[0098] Figure 8 is a flow chart illustrating a method for controlling aerosol generation in the aerosol generating device of FIG. 2 .

[0099] It should be appreciated that the drawings are for illustration purposes and are not drawn to scale.

[0100] Figure 1 A schematic side cross-sectional view of an aerosol-generating article 100 is illustrated. The aerosol-generating article 100 comprises a strip 110 of an aerosol-forming substrate and a downstream section 115 at a position downstream of the strip 110 of the aerosol-forming substrate. The aerosol-generating article 100 comprises an upstream section 150 at a position upstream of the strip 110 of the aerosol-forming substrate. Thus, the aerosol-generating article 100 extends from an upstream end or distal end 180 to a downstream end or mouth end 170. In use, air is drawn by a user from the distal end 180 through the aerosol-generating article 100 to the mouth end 170.

[0101] The downstream section 115 comprises a support element 120 located immediately downstream of the strip 110 of aerosol-forming substrate, the support element 120 being longitudinally aligned with the strip 110. The upstream end of the support element 120 abuts the downstream end of the strip 110 of aerosol-forming substrate. In addition, the downstream section 115 comprises an aerosol-cooling element 130 located immediately downstream of the support element 120, the aerosol-cooling element 130 being longitudinally aligned with the strip 110 and the support element 120. The upstream end of the aerosol-cooling element 130 abuts the downstream end of the support element 120. In use, volatile material released from the aerosol-forming substrate 110 passes along the aerosol-cooling element 130 towards the mouth end 170 of the aerosol-generating article 100. The volatile material may cool within the aerosol-cooling element 130 to form an aerosol for inhalation by a user.

[0102] The support element 120 includes a first hollow tubular segment 125. The first hollow tubular segment 125 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The first hollow tubular segment 125 defines an inner cavity 145 extending from an upstream end 165 of the first hollow tubular segment 125 to a downstream end 175 of the first hollow tubular segment 125.

[0103] The aerosol-cooling element 130 includes a second hollow tubular segment 135. The second hollow tubular segment 135 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The second hollow tubular segment 135 defines an inner cavity 155 extending from an upstream end 185 of the second hollow tubular segment 135 to a downstream end 195 of the second hollow tubular segment 135. In addition, a ventilation zone (not shown) is provided at a position along the second hollow tubular segment 135. The ventilation level of the aerosol-generating article 100 is about 25%.

[0104] The downstream section 115 also includes a mouthpiece 140 positioned immediately downstream of the aerosol-cooling element 130. Figure 1 As shown in the Figures, the upstream end of the mouthpiece 140 abuts the downstream end 195 of the aerosol-cooling element 130. The mouthpiece 140 is provided in the form of a cylindrical filter segment of low density cellulose acetate.

[0105] The aerosol-generating article 100 further comprises an elongated susceptor 160 within the strip 110 of the aerosol-generating substrate. In more detail, the susceptor 160 is arranged substantially longitudinally within the aerosol-forming substrate 110 so as to be generally parallel to the longitudinal direction of the strip 110. Figure 1 As shown in the figures of FIG. 1 , the susceptor 160 is positioned in a radially central position within the strip and effectively extends along the longitudinal axis of the strip 110 .

[0106] The susceptor 160 extends from the upstream end to the downstream end of the strip of aerosol-forming substrate 110. In practice, the susceptor 160 has substantially the same length as the strip of aerosol-forming substrate 110. The susceptor 160 is positioned in thermal contact with the aerosol-forming substrate 110 such that the aerosol-forming substrate 110 is heated by the susceptor 160 when the susceptor 160 is heated.

[0107] The upstream section 150 comprises an upstream element 190 located immediately upstream of the strip 110 of aerosol-forming substrate, the upstream element 190 being longitudinally aligned with the strip 110. The downstream end of the upstream element 190 abuts the upstream end of the strip of aerosol-forming substrate. This advantageously prevents the susceptor 160 from being displaced. Furthermore, this ensures that the consumer does not accidentally contact the heated susceptor 160 after use. The upstream element 190 is provided in the form of a cylindrical filter segment of cellulose acetate defined by a rigid wrapper.

[0108] The susceptor 160 includes at least two different materials. The susceptor 160 includes at least two layers: a first layer of a first susceptor material disposed in physical contact with a second layer of a second susceptor material. The first susceptor material and the second susceptor material may each have a Curie temperature. In this case, the Curie temperature of the second susceptor material is lower than the Curie temperature 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.

[0109] The susceptor 160 may be formed by electroplating at least one patch of a second susceptor material onto a strip of a first susceptor material. The susceptor may be formed by cladding a strip of the second susceptor material onto a strip of the first susceptor material.

[0110] Figure 1 The aerosol-generating article 100 shown in FIG. 1 is designed to be used with an aerosol-generating device, such as Figure 2A The aerosol generating device 200 shown in FIG. 1 is engaged for generating an aerosol. The aerosol generating device 200 comprises a housing 210 having a cavity 220 configured to receive an aerosol generating article 100, and an induction heating device 230 configured to heat the aerosol generating article 100 for generating an aerosol. Figure 2B The aerosol-generating device 200 is illustrated when the aerosol-generating article 100 is inserted into the cavity 220 .

[0111] The induction heating device 230 is Figure 3 The induction heating device 230 includes a DC power supply 310 and a heating device 320 (also referred to as power electronics). The heating device 320 includes a controller 330 , a DC / AC converter 340 , a matching network 350 and an inductor 240 .

[0112] The DC power supply 310 is configured to provide DC power to the heating device 320. Specifically, the DC power supply 310 is configured to provide a DC supply voltage (V DC ) and DC current (I DC ). Preferably, the power source 310 is a battery, such as a lithium-ion battery. Alternatively, the power source 310 may be another form of charge storage device, such as a capacitor. The power source 310 may need to be recharged. For example, the power source 310 may have sufficient capacity to allow continuous generation of aerosol for a period of about six minutes, or for a period of an integral multiple of six minutes. In another example, the power source 310 may have sufficient capacity to allow a predetermined number of puffs or discontinuous activation of the heating device.

[0113] The DC / AC converter 340 is configured to supply a high-frequency alternating current to the inductor 240. As used herein, the term "high-frequency alternating current" refers to an alternating current having a frequency between about 500 kilohertz and about 30 megahertz. The high-frequency alternating current may have a frequency between about 1 megahertz and about 30 megahertz, such as between about 1 megahertz and about 10 megahertz, or, for example, between about 5 megahertz and about 8 megahertz.

[0114] Figure 4 The electrical components of the induction heating device 230, in particular the DC / AC converter 340, are schematically illustrated. The DC / AC converter 340 preferably comprises a class E power amplifier. The class E power amplifier comprises a transistor switch 410 comprising a field effect transistor 420 (e.g. 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 comprising a parallel capacitor C1 and a series connection of a capacitor C2 and an inductor L2 corresponding to the inductor 240. In addition, a DC power supply 310 comprising a choke coil L1 is shown for supplying a DC supply voltage V DC , DC current I DC During operation, the DC power source 310 is drawn from the DC power source 310. Figure 5 The ohmic resistance R representing the total ohmic load 450 is shown in more detail in FIG. 4 , which is the ohmic resistance R of the inductor L2. coil and the ohmic resistance R of the sensor 160 load The sum of .

[0115] Although DC / AC converter 340 is illustrated as including a class E power amplifier, it should be understood that DC / AC converter 340 may use any suitable circuit that converts DC current into AC current. For example, DC / AC converter 340 may include a class D power amplifier including two transistor switches. As another example, DC / AC converter 340 may include a full-bridge power inverter having four switching transistors that act in pairs.

[0116] Back to Figure 3 , the inductor 240 can receive an alternating current from the DC / AC converter 340 via a matching network 350 to best suit the load, but the matching network 350 is not required. The matching network 350 can include a small matching transformer. The matching network 350 can improve the power transfer efficiency between the DC / AC converter 340 and the inductor 240.

[0117] like Figure 2AAs shown in , the inductor 240 is positioned adjacent to the distal portion 225 of the cavity 220 of the aerosol generating device 200. Therefore, the high-frequency alternating current supplied to the inductor 240 during operation of the aerosol generating device 200 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 between 1 MHz and 30 MHz, preferably between 2 MHz and 10 MHz, for example between 5 MHz and 7 MHz. As shown in FIG. Figure 2B It can be seen that when the aerosol generating article 100 is inserted into the cavity 200, the aerosol-forming substrate 110 of the aerosol generating article 100 is positioned adjacent to the inductor 240 so that the susceptor 160 of the aerosol generating article 100 is 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 in the susceptor 160, as a result of which the susceptor is heated. Further heating is provided by 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.

[0118] The controller 330 may be a microcontroller, preferably a programmable microcontroller, and is programmed to regulate the power supply from the DC power source 310 to the induction heating device 320 in order to control the temperature of the susceptor 160 .

[0119] Figure 6 shows the DC current I drawn from the power supply 310 as the temperature of the susceptor 160 (indicated by the dashed line) increases. DC The relationship between time. More specifically, Figure 6 The solid line 600 of FIG. 600 shows the remotely detectable DC current change that occurs when the susceptor material undergoes a phase change associated with its Curie point. The DC current I drawn from the power source 310 DC Measured at the input side of the DC / AC converter 340. For the purpose of this description, it can be assumed that the voltage V DC Keep it roughly constant.

[0120] When the susceptor 160 is inductively heated, the apparent resistance of the susceptor 160 increases. This increase in resistance is observed as a DC current I drawn from the power supply 310. DCThe DC current decreases when the temperature of the susceptor 160 increases at a constant voltage. The high frequency alternating magnetic field provided by the inductor 240 induces eddy currents in close proximity to the susceptor surface, an effect known as the skin effect. The resistance in the susceptor 160 depends in part on the resistivity of the first susceptor material, the resistivity of the second susceptor material, and in part on the depth of the skin layer in each material available for induced eddy currents, which in turn is temperature dependent.

[0121] When the second susceptor material reaches its Curie temperature it loses its magnetic properties. This causes an increase in the skin layer available for eddy currents in the second susceptor material, which causes a decrease in the apparent resistance of the susceptor 160. The result is a detected DC current I DC Then, as the skin depth of the second susceptor material begins to increase, the resistance begins to decrease. Figure 6 The middle is regarded as a valley (local minimum 610).

[0122] As heating continues, the current continues to increase until the maximum skin depth is reached, which coincides with the point at which the second susceptor material has lost its spontaneous magnetic properties. This point is called the Curie temperature and is Figure 6 620). 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, the susceptor 160 is at a known temperature (the Curie temperature, which is an intrinsic material-specific temperature).

[0123] If the inductor 240 continues to generate the alternating magnetic field after the Curie temperature has been reached (i.e., the power supplied to the DC / AC converter 340 is not interrupted), the eddy currents generated in the susceptor 160 will act against the resistance of the susceptor 160, so that Joule heating in the susceptor 160 will continue, and thus the resistance will increase again (the resistance will have a polynomial dependence on temperature, which for most metallic susceptor materials can be approximated to a cubic polynomial dependence for our purposes), and the current will begin to decrease again as long as the inductor 240 continues to supply power to the susceptor 160.

[0124] Therefore, the second susceptor material is heated by Figure 6 The first turning point 610 (corresponding to the local minimum of the current and the local maximum of the resistance) corresponds to the beginning of the phase change. The second turning point 620 (corresponding to the local maximum of the current and the local minimum of the resistance) corresponds to the end of the phase change.

[0125] from Figure 6 It can be seen that the DC current I drawn from the power supply 310 can be monitored DCThe apparent resistance of the susceptor 160 and thus the start and end of the phase change can be remotely detected. Alternatively, the conductance value (where conductance is defined as the DC current I DC With DC supply voltage V DC ratio) or resistance value (where resistance is defined as the DC supply voltage V DC With DC current I DC The controller 330 monitors at least the DC current I drawn from the power source 310. DC Although the DC supply voltage V DC It is known, but preferably, the DC current I drawn from the power supply 310 is monitored. DC and DC supply voltage V DC Both. DC current I DC , conductance and resistance values ​​can be called power supply parameters.

[0126] As from Figure 6 As can be seen in FIG. 1 , within certain temperature ranges of the susceptor 160, for example, between the valley 610 and the hill 620, the apparent resistance of the susceptor 160 (and accordingly the current I drawn from the power supply 310) is DC ) may vary with the temperature of the susceptor 160 in a strictly monotonic relationship. A strictly monotonic relationship allows the temperature of the susceptor 160 to be determined unambiguously from determining the apparent resistance (R) or the apparent conductance (1 / R). This is because each determined value of the apparent resistance represents only one single value of the temperature, so that there is no ambiguity in the relationship. The monotonic relationship of the temperature and apparent resistance of the susceptor 160 over the temperature range over which the second susceptor material undergoes a reversible phase change allows the temperature of the susceptor 160, and therefore the temperature of the aerosol-forming substrate 110, to be determined and controlled.

[0127] The controller 330 regulates the power supply provided to the heating device 320 based on the power supply parameters. In particular, the heating device 320 may include a current sensor (not shown) to measure the DC current I DC The heating device may optionally include a voltage sensor (not shown) to measure the DC supply voltage V DC The current sensor and the voltage sensor are located at the input side of the DC / AC converter 340. The DC current I DC and an optional DC supply voltage V DC The feedback channel is provided to the controller 330 to control the further supply of AC power P to the inductor 240. AC .

[0128] Controller 330 may control the temperature of susceptor 160 by maintaining the measured power parameter value at a target value corresponding to a target operating temperature of susceptor 160. Controller 330 may maintain the measured power parameter at the target value using any suitable control loop, such as by using a proportional-integral-derivative control loop.

[0129] In order to take advantage of 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 for generating aerosols, the power supply parameter measured at the input side of the DC / AC converter 340 is maintained between a first calibration value corresponding to the first calibration temperature and a second calibration value corresponding to the second calibration temperature. The second calibration temperature is the Curie temperature ( Figure 6 The first calibration temperature is greater than when the skin depth of the second susceptor material begins to increase (causing a temporary decrease in resistance) ( Figure 6 The first calibration temperature is a temperature greater than or equal to the temperature of the susceptor material at the valley 610 in the current graph of the second susceptor. Therefore, the first calibration temperature is a temperature greater than or equal to the temperature at the maximum permeability of the second susceptor material. The first calibration temperature is at least 50 degrees Celsius lower than the second calibration temperature. At least the second calibration value can be determined by calibration of the susceptor 160, as will be described in more detail below. The first calibration value and the second calibration value can be stored as calibration values ​​in the memory of the controller 330. Since the power supply parameters will have a polynomial dependence on temperature, the power supply parameters will act in a nonlinear manner with temperature. However, the first calibration value and the second calibration value are selected so that this dependence can be approximated as a linear relationship between the first calibration value and the second calibration value because the difference between the first calibration value and the second calibration value is small, and the first calibration value and the second calibration value are in the upper part of the operating temperature range. Therefore, in order to adjust the temperature to the target operating temperature, the power supply parameters are adjusted by a linear equation according to the first calibration value and the second calibration value.

[0130] For example, if the first calibration value and the second calibration value are conductance values, the target conductance value corresponding to the target operating temperature may be given by the following equation:

[0131] G Target =G Lower +(x×ΔG)

[0132] Where ΔG is the difference between the first conductance value and the second conductance value, and x is a percentage of ΔG.

[0133] The controller 330 can control the power supply to the heating device 320 by adjusting the duty 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 that heats the susceptor 160, and at the same time, the DC current I can be preferably measured every millisecond within a period of 100 milliseconds. DC and selectable DC supply voltage V DC .

[0134] For example, if conductance or current is monitored by controller 330 to adjust the susceptor temperature, the duty cycle of switching transistor 410 is reduced when the conductance or current reaches or exceeds a value corresponding to the target operating temperature for adjusting the susceptor temperature. If controller 330 monitors resistance for adjusting the susceptor temperature, the duty cycle of switching transistor 410 is reduced when the resistance reaches or falls below a value corresponding to the target operating temperature. For example, the duty cycle of switching transistor 410 can be reduced to about 10%. In other words, switching transistor 410 can be switched to a mode in which it generates a pulse only every 10 milliseconds for 1 millisecond. During this 1 millisecond on-state (conducting state) of switching transistor 410, the DC supply voltage V is measured. DC and DC current I DC As the conductance decreases (or the resistance increases) to indicate that the temperature of the susceptor 160 is below the target operating temperature, the gate of the transistor 410 is again supplied with a series of pulses at the drive frequency selected for the system.

[0135] The controller 330 may supply power to the inductor 240 in the form of a series of continuous pulses of current. In particular, the power may be supplied to the inductor 240 in a series of pulses, each pulse being separated by a time interval. The series of continuous pulses may include two or more heating pulses and one or more detection pulses between the continuous heating pulses. The heating pulses have an intensity that heats the susceptor 160, for example. The detection pulses are isolated power pulses of such intensity that they do not heat the susceptor 160, but rather obtain feedback about the power supply parameters and then obtain feedback about the evolution (reduction) of the susceptor temperature. The controller 330 may control the power by controlling the duration of the time intervals between the continuous heating pulses of the power supplied by the DC power supply to the inductor 240. Additionally or alternatively, the controller 330 may control the power by controlling the length (in other words, the duration) of each continuous heating pulse of the power supplied by the DC power supply to the inductor 240.

[0136] The controller 330 is programmed to perform a calibration process in order to obtain a calibration value at which the power supply parameter is measured at a known temperature of the susceptor 160. The known temperature of the susceptor may be a first calibration temperature corresponding to the first calibration value and a second calibration temperature corresponding to the second calibration value. The calibration process is performed each time the user operates the aerosol generating device 200. For example, the calibration process is performed during a first heating phase of the aerosol generating device before the user operates the aerosol generating device 200 to generate an aerosol. The calibration process may be repeated during the time the user operates the aerosol generating device 200 for generating an aerosol.

[0137] Figure 7 is a graph of conductance versus time showing a heating curve for a susceptor 160, including a first heating phase 710 including the calibration process 710B described above. The first heating phase 710 is followed by a second heating phase 720 for heating an aerosol-forming substrate to generate an aerosol for inhalation by a user of the aerosol generating device.

[0138] although Figure 7 It is shown as a graph of conductance versus time, but it should be understood that the controller 330 may be configured to control the heating of the susceptor 160 during the first heating stage 710 and the second heating stage 720 based on the measured resistance or current as described above.

[0139] During the calibration process, the controller 330 controls the DC / AC converter 340 to continuously or constantly supply power to the inductor 240 in order to heat the susceptor 160. The ... DC and optional supply voltage V DC To monitor power supply parameters. Figure 6 As described above, when the susceptor 160 is heated, the measured current decreases until it reaches a first turning point E (corresponding to Figure 6 610 in FIG. 610 ) and the current begins to increase. This first turning point E corresponds to a local minimum conductance or current value (local maximum resistance value). The controller 330 can record the power supply parameter at the first turning point as a first calibration value.

[0140] When the power parameter is conductance or resistance, the measured current I DC and the measured voltage V DC Alternatively, it can be assumed that the power supply voltage V DCThe first calibration value is a known characteristic of the power source 310. The temperature of the susceptor 160 at the first calibration value is referred to as the first calibration temperature. Preferably, the first calibration temperature is between 150 degrees Celsius and 350 degrees Celsius. More preferably, when the aerosol-forming substrate 110 comprises tobacco, the first calibration temperature is 320 degrees Celsius. The first calibration temperature is at least 50 degrees Celsius lower than the second calibration temperature.

[0141] While the controller 330 continues to control the power provided by the DC / AC converter 340 to the sensor 240, the controller 330 continues to monitor the power parameter until a second turning point F (corresponding to Figure 6 620 in FIG. 620). The second turning point corresponds to the maximum current (corresponding to the Curie temperature of the second susceptor material) before the measured current starts to decrease. This turning point F corresponds to the local maximum conductance or current value (local minimum resistance value). The controller 330 records the power supply parameter value at the second turning point F 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 degrees Celsius and 400 degrees Celsius. When the maximum value is detected, the controller 330 controls the DC / AC converter 340 to interrupt the power supply to the inductor 240, so that the temperature of the susceptor 160 decreases and the measured current decreases accordingly.

[0142] Due to the shape of the graph, this process of continuously heating the susceptor 160 to obtain the first calibration value and the second calibration value can be repeated at least once during the calibration process 710B. After interrupting the supply of power to the inductor 240, the controller 330 continues to monitor the power parameter until a third turning point is observed. The third turning point corresponds to the second minimum conductance or current value (second maximum resistance value). When the third turning point is detected, the controller 330 controls the DC / AC converter 340 to continuously supply power to the inductor 240 until a fourth turning point in the monitored power parameter is observed. The fourth turning point corresponds to the second maximum conductance or current value (second minimum resistance value). The controller 330 stores the power parameter value measured at the third turning point as the first calibration value and stores the power parameter value measured at the fourth turning point as the second calibration value. Repeatedly measuring the turning points corresponding to the minimum and maximum measured currents significantly improves subsequent temperature regulation during user operation of the device for generating aerosols. Preferably, the controller 330 adjusts the power based on the power supply parameter value obtained from the second maximum value and the second minimum value, which is more reliable because the heat will have more time to be distributed within the aerosol-forming substrate 110 and the susceptor 160.

[0143] The controller 330 is configured to detect turning points by measuring a sequence of power supply parameter values. Figure 6 and 7, the sequence of measured power parameter values ​​will form a curve where each value is greater or less than the previous value. The controller 330 is configured to measure the calibration value at the point where the curve begins to flatten out. In other words, the controller 330 records the calibration value when the difference between consecutive power parameter values ​​is below a predetermined threshold.

[0144] Additionally, during the first heating phase 710, the controller 330 is programmed to perform a preheating process 710A prior to the calibration process 710B.

[0145] To perform the preheating process 710A, the controller 330 is configured to continuously provide power to the inductor 240 so that the temperature of the susceptor 160 increases. As described above, the measured current I DC As the temperature of the susceptor 160 increases, it begins to decrease until it reaches a turning point A corresponding to the minimum measured current. During this stage, the controller 330 continues to provide power to the inductor 240, and the measured current I CD The increase starts with the increase in the temperature of the susceptor 110. The controller 330 is configured to interrupt the supply of power to the inductor 240 when the measured power parameter reaches a predetermined value B.

[0146] The predetermined power parameter value when the controller 330 interrupts the power supply to the inductor can be adjusted according to the power parameter value measured at the turning point A. For example, if the power parameter value is conductance, the conductance value when the controller 330 interrupts the power supply to the inductor 240 can be given by the following equation:

[0147] G B =G A +(x×ΔG)

[0148] where x can be between 1.01 and 1.5.

[0149] Alternatively, the controller 330 can be configured to interrupt the power supply to the inductor 240 when the inflection point is reached, i.e., just before the local maximum 620. In this example, the controller 330 is configured to determine the difference between consecutively measured current values. The controller 330 interrupts the power supply to the inductor 240 when the determined difference between consecutively measured current values ​​is below a predetermined threshold difference, wherein the predetermined threshold difference is a power supply parameter value.

[0150] When the supply of power to the inductor 240 is interrupted, the susceptor 160 begins to cool and the value of the monitored current begins to decrease until reaching a local minimum C. The controller 330 may be configured to supply power to the inductor 240 when the measured power parameter value reaches another predetermined power value corresponding to the minimum current value at C. Alternatively, the controller 330 may be configured to supply power to the inductor when the measured current reaches another predetermined power value corresponding to a predetermined value of the current D. Alternatively, the controller 330 is configured to wait for a predetermined period of time to allow the susceptor 160 to cool before continuing to heat.

[0151] The predetermined power supply parameter value is predefined and stored on a memory of the aerosol generating device. The predetermined power supply parameter value is determined before the aerosol generating device is used to generate an aerosol for inhalation by a user. For example, the predetermined power supply parameter value may be determined during manufacture of the aerosol generating device.

[0152] like Figure 7 As shown in , the heating and cooling of the susceptor 160 is repeated within a predetermined duration of the preheating process 710A. The predetermined duration of the preheating process 710A is preferably 11 seconds. The predetermined combined duration of the preheating process 710A and the subsequent calibration process 710B is preferably 20 seconds.

[0153] The preheating process 710A improves the reliability of the calibration process 710B by enabling heat to diffuse uniformly within the susceptor 160 and the aerosol-forming substrate 110 before calibration is performed. More specifically, when energy is provided to the susceptor 160, heating is greatest at the center of the susceptor 160 along the longitudinal axis. In other words, heat generation in the susceptor 160 decreases as one moves away from the center of the susceptor in the axial direction. The heat then diffuses along the susceptor 160 and into the aerosol-forming substrate 110. Thus, a temperature gradient exists within the susceptor 160, and when the susceptor 160 is heated, the temperature increase within the susceptor 160 and the aerosol-forming substrate 110 depends on the axial position along the susceptor 160. However, the measured changes in the power supply parameters are associated with the temperature of the susceptor as a whole. Over time and at elevated temperatures, the temperature gradient decreases as heat diffuses in the susceptor 160 and the aerosol-forming substrate 110.

[0154] Thus, the preheating phase 710A introduces additional energy into the aerosol-generating article to raise the average temperature of the aerosol-generating article, particularly by heating to a temperature above the temperature at the inflection point A and by allowing time for the generated heat to diffuse along the susceptor and into the aerosol-forming substrate.

[0155] During the calibration process 710B, additional energy is provided to the susceptor for a short period of time in order to reach the valley point F. Heat generation occurs primarily in the center of the susceptor, as previously described. However, since more heat has been provided during the preheating phase 710A, the ends of the susceptor are at a higher temperature than if the susceptor were only heated to the temperature achieved when the valley point A was reached during the phase 710A. Therefore, the temperature gradient to reach the valley point F is lower. In addition, in order to maintain the same average susceptor temperature, the maximum temperature reached in the center of the susceptor is lower (because the temperature at the ends is higher). When a lower maximum temperature is reached, this mitigates the risk of overheating the aerosol-forming substrate located near (or in contact with) the center of the susceptor.

[0156] For example, if the aerosol-forming substrate 110 is particularly dry or under similar conditions, calibration may be performed before heat has diffused within the aerosol-forming substrate 110, thereby reducing the reliability of the calibration value. If the aerosol-forming substrate 110 is moist, the susceptor 160 takes more time to reach the valley temperature (due to the water content in the substrate 110). Therefore, performing the preheating process 710A for a predetermined duration ensures that, regardless of the physical condition of the substrate 110, this time is sufficient for the entire aerosol-forming substrate 110 to reach the minimum operating temperature in order to be ready for continuous feeding and to reach the first maximum value F. This allows calibration to be performed as early as possible, but still without running the risk that the substrate 110 will not reach the valley beforehand.

[0157] Furthermore, the aerosol-generating article 100 may be configured such that the current minimum value A is always reached within the predetermined duration of the preheating process 710A. If the current minimum value A is not reached within the predetermined duration of the preheating process 710A, this may indicate that the aerosol-generating article 100 including the aerosol-forming substrate 110 is not suitable for use with the aerosol-generating device 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 110 intended for use with the aerosol-generating device 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-generating device 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-generating device 200 if the controller 330 detects that the current minimum value A is not reached during the predetermined duration of the preheating process.

[0158] The preheating process 710A may be performed in response to receiving a user input (e.g., a user activating the aerosol generating device 200). Additionally or alternatively, the controller 330 may be configured to detect the presence of an aerosol generating article 100 in the aerosol generating device 200, and may perform the preheating process in response to detecting the presence of an aerosol generating article 100 within the cavity 220 of the aerosol generating device 200. The controller 330 may be configured to perform the calibration process 710B in response to detecting the end of the preheating process 710A. The first heating stage 710 may have a duration of between 5 seconds and 30 seconds, preferably between 10 seconds and 20 seconds.

[0159] During the second heating phase 720, the controller 330 is configured to control the operating temperature of the susceptor 160 for generating an aerosol based at least on the first calibration value measured during the calibration process 710B. The second heating phase 720 may have a duration of up to 340 seconds. The controller 330 may stop heating during the second heating phase 720 before the end of the second heating phase 720 in response to receiving a user input. In addition, the controller 330 may be configured to stop the supply of power to the induction heating device during the second heating phase 720 before the end of the second heating phase 720 if a temperature above a predetermined temperature is detected, so as to prevent overheating of the aerosol-forming substrate.

[0160] Figure 7 The second heating stage 720 is shown to include a plurality of conductance steps corresponding to a plurality of temperature steps from a first operating temperature of the susceptor 160 to a second operating temperature of the susceptor 160. The first operating temperature of the susceptor 160 is the temperature at which the aerosol-forming substrate 110 forms an aerosol such that an aerosol is formed during each temperature step. Preferably, the first operating temperature of the susceptor is the lowest temperature at which the aerosol-forming substrate will form a sufficient volume and amount of aerosol to provide a satisfactory experience when inhaled by a user. The second operating temperature of the susceptor is the temperature at which it is desired to heat the aerosol-forming substrate for inhalation of the aerosol by a user.

[0161] The first operating temperature of the susceptor 160 is greater than or equal to the first calibration temperature (corresponding to the first calibration value) of the susceptor 160 ( Figure 6 The first operating temperature may be between 150 degrees Celsius and 330 degrees Celsius. The second operating temperature of the susceptor 160 is less than or equal to a second calibration temperature of the susceptor 160, which corresponds to a second calibration value ( Figure 6 The second operating temperature may be between 200 degrees Celsius and 400 degrees Celsius. The difference between the first operating temperature and the second operating temperature is at least 50 degrees Celsius.

[0162] It should be understood that Figure 7 The number of temperature steps shown in is exemplary. The second heating stage 720 may include at least three consecutive temperature steps, preferably between two temperature steps and fourteen temperature steps, and most preferably between three temperature steps and eight temperature steps. Each temperature step may have a predetermined duration. Preferably, the duration of the first temperature step is longer than the duration of the subsequent temperature step. The duration of each temperature step is preferably longer than 10 seconds, preferably between 30 seconds and 200 seconds, and more preferably between 40 seconds and 160 seconds. The duration of each temperature step may correspond to a predetermined number of user puffs. Preferably, the first temperature step corresponds to four user puffs, and each subsequent temperature step corresponds to one user puff. Alternatively, the controller 330 may be configured to start each temperature step in response to receiving a control signal (e.g., user input).

[0163] During the duration of each temperature step, the temperature of the susceptor 160 is maintained at the target operating temperature corresponding to the corresponding temperature step. Therefore, during the duration of each temperature step, the controller 330 controls the power supply to the heating device 320 so that the measured power supply parameter is maintained at a target value corresponding to the target operating temperature of the corresponding temperature step, wherein the target value is determined with respect to the first calibration value and the second calibration value as described above.

[0164] Alternatively, the controller 330 may be configured to control the power provided to the inductor 240 to maintain the temperature of the susceptor 160 at a constant temperature for the duration of the second heating phase 720. The constant temperature may be between 150 degrees Celsius and 400 degrees Celsius.

[0165] Figure 8 is a flow chart of a method 800 for controlling aerosol generation in an aerosol generating device 200. As described above, the controller 330 may be programmed to perform the method 800.

[0166] The method starts at step 810, where the controller 330 detects user operation of the aerosol generating device 200 for generating an aerosol. Detecting user operation of the aerosol generating device 200 may include detecting user input, for example, a user activating the aerosol generating device 200. Additionally or alternatively, detecting user operation of the aerosol generating device 200 may include detecting that an aerosol generating article 100 has been inserted into the aerosol generating device 200.

[0167] In response to detecting a user operation at step 810, the controller 330 performs the preheating process 710A at step 820. At the end of the predetermined duration of the preheating process, the controller 330 is configured to perform the calibration process 710B as described above (step 830). After completing the calibration process 710B, the controller 330 enters the second heating stage, in which aerosol is generated at step 840.

[0168] For the purpose of this specification and the appended claims, unless otherwise indicated, all numbers representing amounts, quantities, percentages, etc. should be understood to be modified by the term "about" in all cases. Moreover, all ranges include disclosed maximum and minimum points, and include any intermediate ranges therein that may be specifically listed or may not be listed in this article. In this case, the number A can be regarded as including a numerical value within the general standard error for the measurement of the attribute modified by the number A. In some cases used in the appended claims, the number A may deviate from the percentage listed above, provided that the amount of A deviation will not substantially affect the basic characteristics and novel features of the claimed invention. Moreover, all ranges include disclosed maximum and minimum points, and include any intermediate ranges therein that may be specifically listed or may not be listed in this article.

Claims

1. A method for controlling aerosol generation in an aerosol generating device, the aerosol generating device comprising an induction heating device and a power supply for providing power to the induction heating device, and the method comprising: performing, during a first heating phase, a calibration procedure for measuring one or more calibration values ​​associated with a susceptor inductively coupled to the inductive heating device, wherein the susceptor is configured to heat an aerosol-forming substrate, during operation of the aerosol generating device by a user for generating an aerosol; as well as During operation of the aerosol generating device by a user for generating an aerosol, during a second heating phase, controlling the power provided to the induction heating device such that the temperature of the susceptor is adjusted based on the one or more calibration values; The method further comprises, during the first heating phase, performing a preheating process, wherein the preheating process is performed before the calibration process, and wherein the preheating process comprises the following steps: i) controlling the power supplied to the induction heating device so that the temperature of the susceptor increases; ii) monitoring a power supply parameter, wherein the power supply parameter is based at least in part on the current; and iii) interrupting the supply of power to the induction heating device at a first predetermined value of the monitored power parameter, wherein the first predetermined value of the monitored power parameter is associated with a current value greater than a minimum operating current.

2. The method of claim 1, further comprising storing at least the first predetermined value of the monitored power supply parameter in a memory of the aerosol generating device.

3. The method according to claim 1 or 2, wherein: After interrupting the power supply to the induction heating device, the preheating process further comprises the following steps: iv) at a second predetermined value of the monitored power parameter, controlling the power supplied to the induction heating device such that the temperature of the susceptor increases, wherein the second predetermined value of the monitored power parameter is associated with a current value less than the minimum operating current; and vi) repeating steps i) to iv) for a predetermined duration of said preheating process. The method according to claim 3 , wherein the predetermined duration of the heating process is between 10 and 15 seconds.

5. The method according to claim 3 or 4, further comprising: If the monitored power supply parameter does not reach a value corresponding to a minimum operating current for the susceptor during a predetermined duration of the preheating process, operation of the aerosol generating device is stopped.

6. The method according to one of the preceding claims, wherein the one or more calibration values ​​comprise a power supply parameter value corresponding to a minimum operating temperature of the susceptor.

7. The method of claim 6, wherein the one or more calibration values ​​further include a power supply parameter value corresponding to a maximum operating temperature of the susceptor.

8. An aerosol generating device comprising: A power supply, the power supply being used to provide a DC supply voltage and a DC current; power electronics connected to the power supply, the power electronics comprising: DC / AC converter; an inductor connected to the DC / AC converter for generating an alternating magnetic field when excited by an alternating current from the DC / AC converter, the inductor being coupleable to a susceptor, wherein the susceptor is configured to heat the aerosol-forming substrate; and A controller, the controller being configured to: performing a calibration procedure for measuring one or more calibration values ​​associated with the receptor during a first heating phase during operation of the aerosol generating device by a user for generating an aerosol; and during operation of the aerosol generating device by a user for generating an aerosol, during a second heating phase, controlling the power supplied to the susceptor such that the temperature of the susceptor is adjusted based on the one or more calibration values, Wherein, during the first heating stage, the controller is further configured to perform a preheating process, wherein the preheating process is performed before the calibration process, and wherein the preheating process comprises the following steps: i) controlling the power supplied to the susceptor so that the temperature of the susceptor increases; ii) monitoring a power supply parameter, wherein the power supply parameter is based at least in part on the current; and iii) interrupting the supply of power to the inductor at a first predetermined value of the monitored power parameter, wherein the first predetermined value of the monitored power parameter is associated with a current value greater than a minimum operating current.

9. An aerosol generating device according to claim 8, wherein the monitored power supply parameter is conductance or resistance.

10. An aerosol generating device according to claim 8 or 9, wherein monitoring the power supply parameter comprises measuring a plurality of values ​​of the power supply parameter, and wherein interrupting the supply of power to the sensor at a first predetermined value of the monitored power supply parameter comprises determining that a difference between consecutive values ​​of the plurality of values ​​is below a threshold difference.

11. An aerosol generating device according to one of claims 8 to 10, wherein: After interrupting the power supply to the power electronics, the preheating process further comprises the following steps: iv) at a second predetermined value of the monitored power parameter, controlling the power supplied to the susceptor to cause a temperature of the susceptor to increase, wherein the second predetermined value of the monitored power parameter corresponds to a susceptor temperature less than the minimum operating current; and vi) repeating steps i) to iv) for a predetermined duration of said preheating process.

12. An aerosol generating device according to claim 11, wherein the predetermined duration of the heating process is between 10 and 15 seconds.

13. An aerosol generating device according to claim 11 or 12, wherein if the monitored power supply parameter does not reach a value corresponding to the minimum operating current of the susceptor during a predetermined duration of the preheating process, the controller is further configured to stop the operation of the aerosol generating device.

14. An aerosol generating device according to one of claims 8 to 13, wherein the aerosol generating device comprises a cavity configured to receive an aerosol generating article, wherein the aerosol generating article comprises the receptor, and wherein the controller is configured to perform the preheating process in response to detecting the aerosol generating article.

15. An aerosol generating system comprising: An aerosol generating device according to any one of claims 8 to 14; as well as An aerosol-generating article, wherein the aerosol-generating article comprises the aerosol-generating substrate and the susceptor.

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