Method for controlling heating in an aerosol generation system

Abstract

To provide a method for controlling heating in an aerosol generation system (100) equipped with a heater (119).SOLUTION: A method of the present invention includes: a first control step in which predetermined power is supplied to a heater (119), and resistance of the heater (119) is determined, the determined resistance showing the temperature of the heater; monitoring a predetermined condition and recording the resistance of the heater (119) accompanying the detection of the predetermined condition; determining target resistance (RT) in correspondence with a target temperature of the heater (119) on the basis of the recorded resistance; and a second control step in which the power supplied to the heater (119) is adapted so as to be controlled to drive the resistance of the heater (119) toward the target resistance (RT) so that the heater (119) is driven toward the target temperature corresponding to the target resistance (RT).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for controlling heating in an aerosol generating system equipped with a heater, and also to such an aerosol generating system. In particular, the present invention relates to a handheld, electrically operated aerosol generating system that generates an aerosol by vaporizing an aerosol-forming substrate through heating. [Background technology]

[0002] Electrically operated aerosol generating systems are well known. These systems typically consist of a device section having a battery and control electronics, an aerosol-forming substrate, an electric heater comprising at least one resistance heating element arranged to heat the aerosol-forming substrate, and a mouthpiece. In some systems, the aerosol-forming substrate contains a liquid, and an elongated wick is used to transport the liquid aerosol-forming substrate to the heater. The heater typically comprises a coil of resistance heating wire wound around the elongated wick. The heater, wick, and liquid aerosol-forming substrate are often contained within a cartridge that can be installed in or received within the device section. When the user activates the device, current flows through the heater, causing resistance heating, which vaporizes the liquid in the wick. By inhaling through the mouthpiece, or by drawing air through the mouthpiece, air is drawn through the system, accompanied by vapor, which then cools to form an aerosol. The aerosol-filled air leaves the system through the mouthpiece and enters the user's mouth.

[0003] As used herein, the term “aerosol-generating substrate” refers to a substrate having the ability to release volatile compounds that can form aerosols. Such volatile compounds may be released by heating the aerosol-generating substrate. Conveniently, the aerosol-generating substrate may be part of an aerosol-generating article or system. [Overview of the project] [Problems that the invention aims to solve]

[0004] In general, it is desirable for an aerosol generation system to be able to generate consistent aerosols over time. This is particularly true when the aerosol is for human consumption, as variations in the aerosol can impair the user experience and extreme variations can potentially be dangerous. Also in general, it is desirable for an aerosol generation system to generate aerosols as efficiently as possible with respect to the amount of energy required to generate the aerosol. However, this can be difficult to achieve due to variations in the system manufacturing process, variations in the properties of the aerosol-forming substrate used in such systems, and different operating conditions under which such systems are used.

[0005] In an aerosol generation system that uses a liquid aerosol-forming substrate, it is also desirable to be able to detect and avoid a "dry heating" situation, i.e., a situation where the heater is heated in a state where the presence of the liquid aerosol-forming substrate is insufficient. This situation is also known as "dry puffing" and can also lead to overheating and potentially thermal decomposition of the liquid aerosol-forming substrate, which can produce undesirable by-products such as formaldehyde.

[0006] In some cases, it may be desirable to control or regulate the temperature of the heater used to heat the aerosol-forming substrate in order to generate consistent aerosols.

[0007] It is an object of the present invention to provide an aerosol generation system that provides aerosols with more consistent properties during heating of the aerosol-forming substrate. A further object of the present invention is to provide an aerosol generation system that heats the aerosol-forming substrate more efficiently and reduces the possibility of dry puffing.

Means for Solving the Problems

[0008] According to a first aspect of the present invention, a method is provided for controlling heating in an aerosol generating system equipped with a heater, the method comprising: a first control step of supplying a predetermined power to the heater and determining the resistance of the heater, wherein the determined resistance indicates the temperature of the heater; monitoring a predetermined condition and recording the resistance of the heater in accordance with the detection of the predetermined condition; determining a target resistance corresponding to a target temperature of the heater based on the recorded resistance; and a second control step of ensuring that the power supplied to the heater is controllably adapted to drive the resistance of the heater toward the target resistance, thereby driving the heater toward a target temperature corresponding to the target resistance.

[0009] One way to control or regulate the temperature of a heater is through power regulation. In a power-regulated system, a predetermined or constant power is supplied to the heater, and the heater's resistance is monitored. Since the relationship between the heater's electrical resistance and its temperature is generally known or can be determined, the heater's resistance can serve as an indicator of its temperature. For example, the electrical resistance of a heater may be known to be proportional to its temperature, in which case there is a substantially linear relationship between resistance and temperature.

[0010] With a predetermined or constant power supply, the heater temperature initially rises rapidly (e.g., within approximately 0.3 seconds) toward the target temperature. Generally, the power is selected so that the heater temperature begins to stabilize within the target temperature range. However, the power required to maintain the heater temperature at the target temperature is generally less than the power required to heat the heater. As a result, if a constant power supply to the heater continues, the heater temperature will continue to rise above the target temperature, but at a slower rate, for a certain period of time. If the resistance becomes too high, i.e., the heater temperature rises above the target temperature, the power to the heater can be reduced or stopped by monitoring the resistance. However, the heater temperature tends to "rise above" the target temperature in power-controlled systems. This can be undesirable as it can lead to increased aerosol generation and thus variability in aerosol delivery during user inhalation. Furthermore, a temperature rise above the target temperature means that energy is wasted and negatively impacts the efficiency of the device.

[0011] Another way to control or regulate heater temperature is resistance regulation. In a resistance regulation system, a target resistance indicating a target temperature is set, and the power supplied to the heater is adapted so that the heater's resistance is driven toward the target resistance region, or is in or within the target resistance region. However, regulating temperature using resistance regulation can be problematic due to the difficulty in calculating the target resistance, which is caused by various factors affecting the heater's resistance, such as manufacturing variations, contact resistance variations, changes in the properties of the aerosol generating substrate, different ambient temperatures, and different geometric shapes, materials, and resistances of various heaters.

[0012] A method according to a first aspect of the present invention uses two control steps to control heating in an aerosol generation system: a first control step based on power adjustment and a second control step based on resistance adjustment. This results in a hybrid adjustment method, which means that the advantages of both types of adjustment can be utilized while reducing the disadvantages of each type. Such a hybrid method offers numerous benefits, including the following:

[0013] The first control step, which is based solely on power adjustment, requires supplying a constant power to the heater and determining the heater's resistance. There is no need to adjust the power during this control step; therefore, the control is relatively simple and uses fewer control resources compared to resistance adjustment. This is advantageous because there is less need to adjust the temperature during the initial stages of the heating cycle, i.e., while the heater is simply heating.

[0014] Upon detection of a predetermined condition, the resistance is recorded, and the recorded resistance can be used to determine the target resistance. Since the target resistance is simply based on the heater resistance recorded when the predetermined condition is detected, it can be determined independently of various factors that may affect the heater resistance in other ways, such as manufacturing variations, contact resistance variations, changes in the properties of the aerosol generating substrate, different ambient temperatures, and different geometric shapes, materials, and resistances of various heaters.

[0015] Following the determination of the target resistance, a second control step based on resistance adjustment can be used, in which the power supplied to the heater is controllably adapted to drive the heater's resistance toward the target resistance, thereby driving the heater toward a target temperature corresponding to the target resistance. This reduces the possibility of the heater temperature rising above the target temperature. As a result, the consistency or uniformity of the properties of the generated aerosol is improved during and for subsequent inhalation. For example, the volume of the delivered aerosol, as well as the components contained within the aerosol, can be made more consistent. This results in an overall improvement in the user experience. Furthermore, by reducing temperature rises exceeding a certain degree, less energy is wasted and the efficiency of the system is improved.

[0016] As used herein, the term "target resistance" refers to the electrical resistance of a heater, determined based on the heater's resistance recorded when certain conditions are detected. As described above, the relationship between the electrical resistance of a heater and the heater's temperature is generally known or can be determined; therefore, the heater's resistance can serve as an indicator of the heater's temperature. Accordingly, the target resistance has a corresponding target temperature, and vice versa.

[0017] As used herein, the term “target temperature” refers to the temperature or temperature range corresponding to the target resistance. The target temperature is sufficient to generate aerosols from the aerosol-forming substrate, but below the temperature at which thermal decomposition of the aerosol-forming substrate occurs or undesirable byproducts are generated.

[0018] The method may switch from the first control process to the second control process upon detection of a predetermined condition. This enables a rapid response to the predetermined condition.

[0019] As used herein, the term “predetermined conditions” refers to conditions or criteria indicating that the heater resistance is at or near the target resistance. These conditions may be known or determined before performing this method. As described above, when power is supplied to the heater, the heater temperature, and therefore the heater resistance, initially rises rapidly and then begins to stabilize around the target temperature. The point at which the resistance begins to stabilize can be monitored, and various points within the stabilization can be set as predetermined conditions.

[0020] The specified conditions may be selected from one or more different conditions, as follows:

[0021] For example, the specified condition may be the elapsed time since the start of user inhalation. The time it takes for the resistance to stabilize at or near the target temperature may be known or can be determined, and this time can be used as the specified condition.

[0022] As another example, the given condition may be the derivative of the resistance below a predetermined threshold. As used herein, the term “derivative of resistance” refers to a measure of sensitivity to the change in resistance with respect to a change in another variable. For example, the derivative may be the rate of change of resistance over time (e.g., the slope of a resistance-time curve), or the derivative may be the absolute change in resistance over a sampling time. As the resistance begins to stabilize around the target temperature, the rate of change of resistance over time begins to decrease. The given condition may be a specific value for the rate of change of resistance, and the method may monitor when the rate of change of resistance falls below this value.

[0023] As another example, the predetermined condition may be the derivative of resistance equal to zero. When the heater temperature reaches its maximum temperature, it reaches a given power, the rate of temperature change becomes zero, and therefore the rate of resistance change becomes zero. This rate of change of resistance equal to zero may be used as the predetermined condition.

[0024] In addition, the specified conditions can be any appropriate criteria based on resistance and / or time.

[0025] The first and second control steps may be performed during user inhalation and optionally during each user inhalation or smoke inhalation. This allows for setting a target resistance value and effectively optimizing it for each inhalation. This is particularly useful when the target resistance may change between smoke inhalations, for example, when the aerosol-forming substrate is becoming depleted or when ambient operating conditions are changing rapidly.

[0026] As used herein, the terms “inhalation” and “smoke inhalation” are interchangeable and are intended to refer to the action of a user inhaling the edge of the system to draw aerosols out of the system.

[0027] The first and second control steps may be performed during the first user inhalation, and the second user inhalation and subsequent user inhalations may use only the second control step. This allows the target resistance to be set by the first user inhalation and used in all subsequent inhalations so that a consistent aerosol is produced throughout all subsequent inhalations during a particular user session. If desired, the heater temperature can be raised to the target temperature more quickly than using the first control step, which is based on power adjustment, because the second control step is not limited by the need to supply constant power. In other words, the power can be increased beyond the constant output of the first control step if the system requires to drive the heater temperature more quickly toward the target temperature.

[0028] The target resistance may be determined after several initial user inhalations. Optionally, only the first control step and the step of monitoring and detecting predetermined conditions and recording the resistance may be performed during the initial user inhalations. In this option, the switch to the second control mode occurs between inhalations, not during inhalations.

[0029] The target resistance may be determined based on the average of recorded resistances from multiple initial user inhalations. A target resistance based on the average of recorded resistances from multiple initial user inhalations may allow for taking into account fluctuations in the initially recorded resistance, for example, during the initial startup of the aerosol generating system before the system has thermally stabilized, or if ambient operating conditions change abruptly at startup (for example, by a user moving from outdoors to indoors), or to eliminate those resistance fluctuations and make them constant.

[0030] For subsequent user inhalations after multiple initial user inhalations, only the second control step may be used, and the target resistance may be based on the average of the recorded resistances from the multiple initial user inhalations. This may provide consistent aerosol generation for subsequent inhalations in a particular user use session. If desired, the heater temperature can be raised to the target temperature more quickly than using the first control step based on power adjustment, since the second control step is not limited by the need to supply constant power.

[0031] According to a second aspect of the present invention, an aerosol generating system is provided comprising a heater, a power supply and a controller, wherein the controller is configured to supply a predetermined power to the heater and to determine the resistance of the heater in a first control mode so that the determined resistance indicates the temperature of the heater; to monitor predetermined conditions and record the resistance of the heater upon detection of the predetermined conditions; to determine a target resistance corresponding to a target temperature of the heater based on the recorded resistance; and to drive the resistance of the heater toward the target resistance in a second control mode so that the heater is driven toward a target temperature corresponding to the target resistance.

[0032] A system according to a second aspect of the present invention uses two control modes to control heating in an aerosol generation system: a first control mode based on power adjustment and a second control mode based on resistance adjustment. The first and second control modes correspond to the first and second control steps of the method according to the first aspect of the present invention. As a result, the system is configured with hybrid temperature control, which means that the advantages of both types of control can be utilized while the disadvantages of each type can be reduced. Such hybrid control offers numerous benefits, which have been described above under the first aspect of the present invention and will not be repeated here for the sake of brevity.

[0033] The controller may be configured to switch from a first control mode to a second control mode upon detection of a predetermined condition. This enables a rapid response to the predetermined condition.

[0034] The predetermined conditions may be selected from one or more of the following: i) elapsed time since the start of the user's inhalation, ii) the derivative of resistance below a predetermined threshold, and iii) the derivative of resistance equal to zero. Each of these predetermined conditions is identical to the predetermined conditions in the first aspect of the present invention, as described above. For the sake of brevity, that description will not be repeated here. In addition, the predetermined conditions can be any suitable criteria based on resistance and / or time.

[0035] The first and second control modes may be used during user inhalation and, optionally, during each user inhalation. This allows for setting a target resistance value and effectively optimizing it for each inhalation. This is particularly useful when the target resistance may change between inhalations, for example, when the aerosol-forming substrate is becoming depleted or when ambient operating conditions are changing rapidly.

[0036] The first and second control modes may be used during the first user inhalation, and the second user inhalation and subsequent user inhalations may use only the second control mode. This allows the target resistance to be set by the first user inhalation and used for all subsequent inhalations, so that a consistent aerosol is produced throughout all subsequent inhalations during a particular user session. If desired, the heater temperature can be raised to the target temperature more quickly than with the first control mode, which is based on power adjustment, because the second control mode is not limited by the need to supply constant power. In other words, the power can be increased beyond the constant output of the first control mode if the system requires to drive the heater temperature more quickly toward the target temperature.

[0037] The target resistance may be determined after several initial user inhalations. Optionally, only the first control mode—monitoring and detecting predetermined conditions and recording the resistance—may be used during the multiple initial user inhalations. In this option, the switch to the second control mode would occur between inhalations, not during inhalations.

[0038] The target resistance may be determined based on the average of recorded resistances from multiple initial user inhalations. A target resistance based on the average of recorded resistances from multiple initial user inhalations may allow for variations in the determined target resistance, or eliminate those variations and make them constant, for example, during the initial startup of the aerosol generating system before the system has thermally stabilized, or if ambient operating conditions change abruptly at startup (for example, by a user moving from outdoors to indoors).

[0039] After multiple initial user inhalations, subsequent user inhalations may use only the second control mode, and the target resistance may be based on the average of the recorded resistances from multiple initial user inhalations. This may provide consistent aerosol generation for subsequent inhalations in a particular user use session. If desired, the heater temperature can be raised to the target temperature more quickly than using the first control mode, which is based on power adjustment, because the second control mode is not limited by the need to supply constant power.

[0040] In both the first and second embodiments of the present invention, the heater may include an electrically resistive heating element. The heater may also include an electrically resistive material. Suitable electrically resistive materials include, but are not limited to, semiconductors such as doped ceramics, conductive ceramics (e.g., molybdenum disilide), carbon, graphite, metals, alloys, and composite materials made of ceramic and metallic materials. Such composite materials may include doped ceramics or undoped ceramics. A suitable example of a doped ceramic is doped silicon carbide. Suitable examples of metals include titanium, zirconium, tantalum platinum, gold, and silver. Suitable metal alloys include stainless steel, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, gold-containing, and iron-containing alloys, as well as nickel, iron, cobalt, stainless steel-based superalloys, Timetal®, and iron-manganese-aluminum alloys. In composite materials, the electrical resistive material may be embedded in, sealed in, or coated with an insulating material, depending on the required energy transfer dynamics and external physicochemical properties.

[0041] In both the first and second embodiments of the present invention, the heater may comprise an internal heating element, an external heating element, or both an internal and an external heating element, where “internal” and “external” refer to their position relative to the aerosol-forming substrate. The internal heating element may take any suitable form. For example, the internal heating element may take the form of a heating blade. Alternatively, the internal heater may take the form of a casing or substrate having different conductive or electrically resistive metal tubes. Alternatively, the internal heating element may be one or more heating needles or rods passing through the center of the aerosol-forming substrate. Other alternatives include heating wires or filaments, such as Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wires, or heating plates. Optionally, the internal heating element may be placed in or on a rigid carrier material. In one such embodiment, the electrically resistive heating element may be formed using a metal having a clear relationship between temperature and resistivity. In such exemplary devices, the metal may be formed as a track on a suitable insulating material such as a ceramic material and then sandwiched between other insulating materials such as glass. A heater formed in this manner may be used during operation for both heating the heating element and monitoring its temperature.

[0042] The heater may include a fluid-permeable heating element. The fluid-permeable heating element may be substantially flat and may also include a conductive filament. The conductive filament may be placed in a single plane. In other embodiments, the substantially flat heating element may be curved along one or more dimensions, for example, to form a dome shape or a bridge shape.

[0043] The conductive filaments may have defined gaps between them, and these gaps may have a width of 10 μm to 100 μm. The filaments may create capillary action in the gaps, which in turn draws the liquid aerosol-forming substrate into the gaps during use, increasing the contact area between the heating element and the liquid.

[0044] The conductive filaments may form a mesh of size 160 to 600 mesh US (±10%) (i.e., 160 to 600 filaments per inch (±10%)). The gap width is preferably 75 μm to 25 μm. The ratio of the mesh opening area, which is the ratio of the gap area to the total mesh area, is preferably 25 to 56%. The mesh may be formed using different types of woven or lattice structures. Alternatively, the conductive filaments consist of an array of filaments arranged parallel to each other.

[0045] The conductive filament may have a diameter of 10 μm to 100 μm, preferably 8 μm to 50 μm, and more preferably 8 μm to 39 μm. The filament may have a round cross-section or a flat cross-section. The heater filament may be formed by etching a sheet material (such as foil). If the heater assembly includes a mesh or fabric of filaments, the filaments may be formed individually and then woven together.

[0046] The area of ​​the fluid-permeable heating element may be, for example, 50 square millimeters or less, preferably 25 square millimeters or less, and more preferably approximately 15 square millimeters.

[0047] The electrical resistance of the conductive filament mesh, array, or fabric of the heating element may be 0.3 ohms to 4 ohms. Preferably, the electrical resistance is 0.5 ohms or higher. More preferably, the electrical resistance of the conductive filament mesh, array, or fabric is 0.6 ohms to 0.8 ohms.

[0048] The aerosol-forming substrate may be a liquid aerosol-forming substrate. If a liquid aerosol-forming substrate is provided, the aerosol generation system preferably includes means for holding the liquid. For example, the liquid aerosol-forming substrate may be held in a liquid storage section or container. Alternatively, or additionally, the liquid aerosol-forming substrate may be absorbed into a porous carrier material. The porous carrier material may be made of any suitable absorbent plug or body, such as foamed metal or plastic material, polypropylene, terylene, nylon fiber, or ceramic.

[0049] If a liquid aerosol-forming substrate is provided, both the first and second embodiments of the present invention may be configured to detect dry fume extraction, for example, by detecting when a recorded resistance increases above a threshold, or by detecting when the power required to maintain the heater at a target resistance decreases below a threshold.

[0050] The aerosol-forming substrate may be a solid aerosol-forming substrate. Alternatively, the aerosol-forming substrate may comprise both solid and liquid components. The aerosol-forming substrate may contain a tobacco-containing material that includes volatile tobacco-flavored compounds released from the substrate upon heating. Alternatively, the aerosol-forming substrate may contain a non-tobacco material. The aerosol-forming substrate may further contain aerosol-forming bodies. Suitable examples of aerosol-forming bodies are glycerin and propylene glycol.

[0051] The aerosol generating system may comprise a housing having a mouthpiece portion and a main body portion. The main body portion may include a power supply (e.g., a rechargeable lithium-ion battery), a control circuit having a controller (e.g., a microcontroller), and a user interface for activating the heater (e.g., a smoke inhalation detection device or push button). The mouthpiece portion may comprise a liquid storage portion, such as a cartridge containing a liquid aerosol generating substrate. The cartridge may include capillary material for transporting the liquid aerosol forming substrate to the heater. The cartridge may also comprise a heater.

[0052] The control circuit may be configured to supply power to the heating element as a series of voltage pulses. The power supplied to the heating element may then be adjusted by adjusting the load cycle of the voltage pulses. The load cycle may be adjusted by changing the pulse width, the pulse frequency, or both. Alternatively, the circuit may be configured to supply power to the heating element as a continuous DC signal. A proportional-integral-derivative (PID) control loop may be used to drive the heater resistance toward a target resistance.

[0053] According to a third aspect of the present invention, a controller for an aerosol generation system is provided, the controller is configured to perform any of the methods described above.

[0054] According to a fourth aspect of the present invention, a computer program is provided which, when executed by a programmable controller for an aerosol generation system, causes the programmable controller to execute any of the methods described above.

[0055] Features described in reference to one aspect of the present invention may also apply equally to other aspects of the present invention.

[0056] Here, for illustrative purposes only, embodiments of the present invention will be described with reference to the following attached drawings. [Brief explanation of the drawing]

[0057] [Figure 1] Figure 1 is a schematic diagram of an aerosol generation system according to one embodiment of the present invention. [Figure 2] Figure 2 is a schematic diagram of the temperature profile of the heater of the aerosol generation system obtained by the method according to an embodiment of the present invention. [Figure 3] Figure 3 is a schematic diagram of the temperature profile of the heater of an aerosol generation system obtained by a method according to another embodiment of the present invention. [Figure 4] Figure 4 is a schematic diagram of the temperature profile of the heater of an aerosol generation system obtained by a method according to another embodiment of the present invention. [Figure 5] Figure 5 is a schematic diagram of the temperature profile of the heater of an aerosol generation system obtained by a method according to another embodiment of the present invention. [Figure 6] Figure 6 is a schematic diagram of the temperature profile of the heater of an aerosol generation system obtained by a method according to another embodiment of the present invention. [Figure 7] Figure 7 is a schematic diagram of the heater temperature profile of an aerosol generation system exhibiting dry fume extraction conditions. [Figure 8] Figure 8 is a schematic diagram of the heater temperature profile of an aerosol generation system exhibiting a different dry fume extraction situation. [Figure 9] Figure 9 is a schematic diagram of the temperature control circuit of the aerosol generation system of the type shown in Figure 1. [Modes for carrying out the invention]

[0058] Figure 1 is a schematic diagram of an aerosol generation system. The system 100 comprises a housing 101 having a mouthpiece portion 103 and a main body portion 105. The main body portion 105 provides a power supply 107 (e.g., a rechargeable lithium-ion battery), a control circuit 109 having a controller 110 (e.g., a microcontroller), and a smoke inhalation detection device 111. The mouthpiece portion 103 provides a liquid storage portion 113 (e.g., a cartridge containing a liquid aerosol generation substrate 115), a wick 117 made of capillary material, and a heater 119 having at least one heating element. One end of the wick 117 extends into the cartridge 113, and the other end of the wick 117 is surrounded by the heater 119. The heater 119 is connected to the smoke inhalation detection device 111 via a connection 121, which is then connected to the control circuit 109 by further connections (not shown). The housing 101 also includes an air intake 123 within the area of ​​the smoke detection device 111, an air outlet 125 exiting from the mouthpiece portion 103, and an aerosol forming chamber 127 surrounding the heater 119.

[0059] The liquid aerosol-forming substrate 115 is moved or carried by the wick 117 via capillary action from the cartridge 113 to the end of the wick surrounded by the heater 119. During use, the user inhales through the mouthpiece portion 103 or inhales through the mouthpiece portion 103, and ambient air is drawn out through the air intake port 123. Inhalation or inhalation is detected or sensed by the inhalation detection device 111, which activates the heater 119. The battery 107 supplies energy to the heater 119 to heat the end of the wick 117 surrounded by the heater. The liquid at that end of the wick 117 is vaporized by the heater 119, creating a supersaturated vapor. Simultaneously, the vaporized liquid is replaced by further liquid moving along the wick 117 by capillary action. The supersaturated vapor produced is mixed with the airflow from the air intake 123 and carried in the airflow, condensing in the aerosol formation chamber 127 to form an inhalable aerosol, which is then carried toward the outlet 125 and into the user's mouth.

[0060] The controller 110 is programmable and has embedded software or firmware to control the power supplied to the heater 119 in order to adjust the heater temperature. This then affects the heater's temperature profile, which in turn affects the amount of aerosol produced. The controller 110 supplies power to the heater 119 by pulse width modulation (PWM), which transmits power using a series of voltage pulses. The power supplied to the heater can be varied by changing the load cycle of pulses at a constant frequency. The load cycle is the ratio of the time the power is switched on to the time the power is switched off. In other words, it is the ratio of the width of a voltage pulse to the time between voltage pulses. For example, a 5% low load cycle provides far less power than a 95% load cycle.

[0061] Figure 2 shows a graph of resistance R versus time t and the temperature profile of the heater of an aerosol generating system heated by a method according to one embodiment of the present invention. In particular, Figure 2 shows the first three inhalations or snortings of a user's usage session, all of which are controlled by hybrid adjustment, i.e., a combination of power adjustment and resistance adjustment.

[0062] The system is activated at time t0, for example, when the user turns on the system's power. At time t1, the user begins the first inhalation or smoke extraction, which starts the heater. The heater is initially controlled by a first control process or mode based on power adjustment (indicated by PR in the figure), where a certain predetermined power corresponding to a given load cycle is supplied to the heater. The predetermined power may be relatively high (e.g., an 80% to 95% load cycle) to rapidly raise the heater temperature. Providing the predetermined power causes the heater temperature to rise, and the heater resistance is determined at regular intervals to serve as an indicator of the heater temperature. The predetermined power is supplied at time t L1The heater is supplied until a predetermined condition is detected, and at this time, the resistance is locked or recorded, and the target resistance is based on the recorded resistance. RT1 The target resistance is determined. Generally, the target resistance is the same as the recorded resistance, but it is also possible that the target resistance may differ from the recorded resistance (for example, depending on the recorded resistance or to include known error corrections) depending on the system requirements. Using this method, the target resistance is determined independently of any variation in the heater resistance or system characteristics. The target resistance corresponds to the target temperature to which the heater should be heated.

[0063] In the embodiment shown in Figure 2, the predetermined condition is the point at which the rate of change of resistance falls below a specific threshold, that is, the point at which the gradient of the temperature profile decreases to a predetermined value. In particular, in Figure 2, the predetermined condition is the point at which the gradient of the temperature profile approaches zero.

[0064] Time t L1 Then, the heater control switches to a second control process or mode based on resistance adjustment (represented by RR in the diagram), in which process or mode the power supplied to the heater is such that the heater is at a target resistance R T1 The heater's resistance is set to the target resistance R so that it is driven toward the corresponding target temperature. T1 It is controllably adapted to drive toward a target. The second control step or mode is to adjust the resistance using PID control. PID control is incorporated into the software programmed into the controller. To adjust the resistance, the heater resistance is determined, and the determined resistance and the target resistance R are set. T1 The error between these two values ​​is calculated. Next, the power load cycle is adjusted using PID control to compensate for the error and drive the heater toward the target resistance. The resistance is determined at a frequency chosen to match the frequency at which the load cycle is controlled, and may be determined every 100ms or more as needed.

[0065] Time t L1Following the switch to the second control step or mode based on resistance adjustment at, the resistance remains substantially constant at the target resistance R until the user stops their first inhalation or puff at time t2. T1 is maintained substantially constantly.

[0066] In the embodiment of FIG. 2, a hybrid adjustment similar to that described above is used in each subsequent inhalation or puff. The user starts their second inhalation and third inhalation at times t3 and t5, respectively, and the corresponding target resistances R T2 and R T3 are determined at times t L2 and t L3 respectively. Each of the three inhalations in FIG. 2 has its own target resistance, namely R T1 、R T2 、R T3 respectively. The target resistances are substantially similar but slightly different due to slightly different conditions in each inhalation, whereby the target resistances R T1 、R T2 、R T3 are optimized for each inhalation.

[0067] FIG. 3 shows a graph of resistance R against time t and the temperature profile of the heater of an aerosol generating system heated by a method according to another embodiment of the invention. In particular, FIG. 3 shows the first three inhalations or puffs of a user session, in which only the first inhalation is adjusted by hybrid adjustment and the second and subsequent inhalations are adjusted using only resistance adjustment.

[0068] In FIG. 3, the system is activated at time t0 and the user starts their first inhalation or puff at time t1, which activates the heater. The first inhalation in FIG. 3 is adjusted in the same way as the inhalation in FIG. 2. During the first inhalation, the heater is initially controlled by the first control step or mode based on power adjustment. At time t L1 with the detection of a predetermined condition, the resistance is recorded and the target resistance R TThis is determined. At this point, the heater control switches to a second control step or mode based on resistance adjustment, which is used for the remaining inhalation until inhalation ends at time t2.

[0069] In Figure 3, the second and third inhalations begin at times t3 and t5, respectively, at which point the heater is restarted. However, until the inhalations end at times t4 and t6, respectively, they are controlled solely by the second control step based on resistance adjustment. Therefore, the second and subsequent inhalations are controlled at the target resistance R of the first inhalation. T It is adjusted based on this. This provides consistent aerosol generation across all inhalations. In addition, the second control step or mode is not limited to supplying a constant predetermined power, but can supply power up to a 100% load cycle if necessary to bring the heater temperature to the target temperature as quickly as possible, so that the heater can reach the target resistance R more quickly when needed. T This allows the device to reach the corresponding target temperature. As can be seen in Figure 3, the temperature profiles for the second and third inhalations have steeper gradients compared to the first inhalation, indicating a faster rate of temperature change. The second control process or mode used to adjust the second and third inhalations uses PID control to adjust the resistance, which is incorporated into the software programmed into the controller.

[0070] Figure 4 shows a graph of resistance R versus time t and the temperature profile of the heater of the aerosol generating system, which is heated by a method according to another embodiment of the present invention. In particular, Figure 4 shows the first five inhalations or smuggling sessions by the user, in which the first three inhalations are regulated by hybrid adjustment, and the fourth inhalation and subsequent inhalations are regulated using resistance adjustment only.

[0071] In Figure 4, the system is activated at time t0, and the user performs the first inhalation or smoke extraction at time t1, at which point the heater is activated. The first inhalation in Figure 4 is regulated in the same way as the inhalation in Figure 2. During the first inhalation, the heater is initially controlled by a first control process or mode based on power regulation, where a certain predetermined power corresponding to a given load cycle is supplied to the heater. The predetermined power is supplied at time t L1 The heater is supplied until a predetermined condition is detected, at which point the resistance R1 is locked or recorded. In the example in Figure 4, the predetermined condition is when the gradient of the temperature profile approaches zero again. At this point, the target resistance is not determined. Instead, the method first monitors one or more further inhalations or fumes before determining the target resistance.

[0072] Time t in Figure 4 L1 In this process, the heater control switches to a second control process or mode based on resistance adjustment, in which the power supplied to the heater is controllably adapted to drive the heater's resistance toward the recorded resistance R1 so that the heater is driven toward the temperature corresponding to the recorded resistance R1. The second control process or mode uses PID control, which is built into the software programmed into the controller to adjust the resistance.

[0073] Time t in Figure 4 L1 Following a second control step or mode switch based on resistance adjustment, the resistance is maintained substantially continuously at the recorded resistance R1 until the user stops their first inhalation or smoking at time t2.

[0074] The second and third inhalations in Figure 4 are regulated in the same way as the first inhalation. The second and third inhalations begin at times t3 and t5, respectively, at which point the heater is restarted. The heater is initially controlled by a first control process or mode based on power regulation, at time t L2 and t L3Upon detection of predetermined conditions, resistances R2 and R3 are recorded, respectively. The heater control then switches to a second control step or mode based on the resistance adjustment, which is used for the remaining inhalation until the second and third inhalations are completed at times t4 and t6, respectively.

[0075] The three separate recorded resistances R1, R2, and R3 from the first three inhalations are used to determine the target resistance R based on the average of the three recorded resistances R1, R2, and R3. T This is used to determine the fourth and fifth inhalations. The fourth and fifth inhalations in Figure 3 are adjusted in the same way as the second and third inhalations. The fourth and fifth inhalations in Figure 4 are started at times t7 and t9, respectively, at which point the heater is started again, but the inhalations are started at times t8 and t 10 Until completion, it is controlled only by the second control step based on resistance adjustment. The fourth and subsequent inhalations are controlled based on the average of the recorded resistances R1, R2, and R3, with a target resistance R T It is adjusted using [a specific method / tool]. This provides consistent aerosol generation for the fourth and subsequent inhalations.

[0076] Figure 5 shows a graph of resistance R versus time t and the temperature profile of the heater of an aerosol generating system heated by a method according to another embodiment of the present invention. In particular, Figure 5 shows the first seven inhalations or smuggling sessions by a user, in which the first five inhalations are regulated by hybrid adjustment, and the sixth inhalation and subsequent inhalations are regulated using resistance adjustment only. This method may be used when the recorded resistance changes significantly during the first few inhalations, i.e., when the resistance fluctuation is outside a predetermined or acceptable range, which may occur, for example, during the initial startup of the aerosol generating system before the system has thermally stabilized.

[0077] In Figure 5, the system is activated at time t0, and the user takes the first three inhalations or smoke inhalations at times t1, t3, and t5, at which point the heater is activated. The first three inhalations in Figure 5 are controlled in the same way as the first three inhalations in Figure 4. During the first three inhalations, the heater is initially controlled by a first control process or mode based on power adjustment. For each inhalation, at time t L1 t L2 t L3 For each inhalation, upon detection of a predetermined condition, separate resistances, namely R1, R2, and R3, are recorded. At this point, the heater control switches to a second control process or mode using resistance adjustment based on the three recorded resistances R1, R2, and R3, and this process or mode is used for the remainder of each inhalation until the inhalation ends at times t2, t4, and t6, respectively.

[0078] The condition for determining the target resistance may be that the resistance recorded for the last n inhalations or smokes falls within a maximum predetermined range ΔRmax. In this case, the target resistance may be based on either the last recorded resistance or the average of the last n inhalations.

[0079] In Figure 5, n is set to 3, and the values ​​of resistors R1, R2, and R3 are within the maximum predetermined range ΔR max It will be outside. In other words, the value obtained by subtracting the minimum value of R1, R2, and R3 from the maximum value of R1, R2, and R3 is the maximum △R within a given range. max Greater than, i.e., maximum {R1, R2, R3} - minimum {R1, R2, R3} > △R max Therefore, the method monitors further inhalation performed by the user rather than determining the target resistance.

[0080] The fourth inhalation is performed at time t7 and is adjusted in the same way as the first three inhalations, i.e., using hybrid adjustment. The fourth resistance R4 is adjusted at time t L4When the predetermined conditions are detected, they are recorded, and the fourth inhalation ends at time t8. Next, this method examines the resistances recorded for the last three inhalations (i.e., R2, R3, R4). However, in Figure 5, these three resistances are also within the maximum predetermined range ΔR max It goes outside. Therefore, the method monitors further inhalation performed by the user rather than determining the target resistance.

[0081] The fifth inhalation is performed at time t9 and is adjusted in the same way as the first four inhalations, i.e., using hybrid adjustment. The fifth resistance R5 is adjusted at time t L5 When the specified conditions are detected, it is recorded, and the fourth inhalation is time t 10 This completes the process. Next, this method examines the resistances recorded for the last three inhalations (i.e., R3, R4, and R5). In Figure 5, these three resistances are within the maximum predetermined range △R max It falls within the range, and therefore the target resistance R T This allows us to determine the target resistance R. T This can be based on the last recorded resistance, i.e., R5, or on the average of the last three recorded resistances, i.e., R3, R4, and R5. In Figure 5, the target resistance R T This is based on the average of the recorded resistances from the last three inhalations, namely R3, R4, and R5.

[0082] The 6th and 7th inhalations are prepared in the same way as the 2nd and 3rd inhalations in Figure 3. The 6th and 7th inhalations in Figure 5 are prepared at time t, respectively. 11 and t 13 It starts at [time], and the heater is restarted at that point, but the intake is each [time] 12 and t 14 Until completion, it is controlled only by the second control step based on resistance adjustment. The 6th and subsequent inhalations are controlled based on the average of the recorded resistances R3, R4, and R5, with a target resistance R T It is adjusted using [a specific method / tool]. This provides consistent aerosol generation for the sixth inhalation and subsequent inhalations.

[0083] Figure 6 shows a graph of resistance R versus time t and the temperature profile of the heater of the aerosol generating system, which is heated by a method according to another embodiment of the present invention. In particular, Figure 6 shows the first five inhalations or smuggling sessions by the user, in which the first three inhalations are controlled by power adjustment alone, and the sixth inhalation and subsequent inhalations are controlled using resistance adjustment alone.

[0084] The first three inhalations in Figure 6 differ from the initial inhalations in other examples shown in the figure in that they are controlled solely by power adjustment. In Figure 6, the system is activated at time t0, the user performs the first inhalation or smoke extraction at time t1, at which point the heater is activated. During inhalation, the heater is controlled by a first control process or mode based solely on power adjustment, where a constant predetermined power corresponding to a predetermined load cycle is supplied to the heater until inhalation ends at time t2. L1 The resistance R1 is recorded when a predetermined condition is detected. In the example in Figure 6, the predetermined condition is when the gradient of the temperature profile approaches zero.

[0085] As described above, power control systems generally use a relatively high predetermined power (e.g., 80% to 95% load cycle) to raise the heater temperature towards the target temperature as quickly as possible. Once the target temperature is reached, the power can be gradually reduced because generally less power is used to maintain the heater at the target temperature than was used for heating. However, since the initial intake does not switch to the second control process or mode during intake, i.e., upon detection of the predetermined conditions, the resistance is not adjusted to the recorded resistance, and therefore the heater temperature continues to rise above the recorded resistance, albeit at a slower rate.

[0086] The target resistance based on the recorded resistance R1 is calculated under a predetermined condition, i.e., time t L1The detection may determine the target temperature. For example, the target temperature can be determined if R1 is within a given range. However, the method shown in Figure 6 takes an alternative approach, first monitoring two more inhalations or fumes using power adjustment alone before determining the target resistance due to resistance fluctuations in the first few inhalations.

[0087] The second and third inhalations in Figure 6 are regulated in the same manner as the first inhalation. The second and third inhalations begin at times t3 and t5, respectively, at which point the heater is restarted. The heater is controlled by the first control process or mode only, based solely on power regulation, until the inhalations end at times t4 and t6, respectively. L2 and t L3 Upon detection of a predetermined condition, resistors R2 and R3 are recorded, respectively.

[0088] The three recorded resistances R1, R2, and R3 from the first three inhalations are used to determine the target resistance R1, R2, and R3, which are based on the average of the three recorded resistances R1, R2, and R3. T This is used to determine the fourth and fifth inhalations, which are controlled in the same way as the second and third inhalations in Figure 3, i.e., using only resistance adjustment. The fourth and fifth inhalations in Figure 6 are started at times t7 and t9, respectively, at which point the heater is started again, but the inhalations are started at times t8 and t9, respectively. 10 Until completion, it is controlled only by the second control step based on resistance adjustment. The fourth and subsequent inhalations are controlled based on the average of the recorded resistances R1, R2, and R3, with a target resistance R T It is adjusted using [a specific method / tool]. This provides consistent aerosol generation for the fourth and subsequent inhalations.

[0089] Alternatively, if the three recorded resistances R1, R2, and R3 are not within the maximum predetermined range, the system can wait until the resistances stabilize and fall within the predetermined range, and then calculate the target resistance based on the average of the recorded resistances in the same manner as described in Figure 5.

[0090] Figure 7 shows a graph of resistance R versus time t and the heater temperature profile of an aerosol generating system according to another embodiment of the present invention where the heater exhibits a dry fume extraction condition. In particular, Figure 7 shows the first three inhalations or fume extractions of a user session where all inhalations are controlled by hybrid control, i.e., a combination of power control and resistance control. As described above, the "dry fume extraction" or "dry heating" condition occurs when the heater is heated in the absence of sufficient liquid aerosol-forming substrate. This can lead to overheating and potentially thermal decomposition of the liquid aerosol-forming substrate, which can produce undesirable byproducts such as formaldehyde.

[0091] In Figure 7, the system is activated at time t0, and the user begins the first inhalation or smoke extraction at time t1, which activates the heater. During the first inhalation, liquid is present in the heater, which is initially controlled by the first control process or mode based on power adjustment. L1 Upon detection of a predetermined condition, the resistance R1 may be recorded, and the target resistance may be determined based on the recorded resistance R1. At this point, the heater control switches to a second control step or mode based on the resistance adjustment, which is used for the remaining suction until the suction is completed at time t2.

[0092] The second and third inhalations in Figure 7 are prepared in the same manner as the first inhalation and initiated at times t3 and t5, respectively. However, there is insufficient liquid aerosol generating substrate available for the second and third inhalations, resulting in dry inhalation. Upon detection of the predetermined conditions, resistance R2 is adjusted during the second inhalation at time t L2 Recorded at time t during the third inhalation, resistance R3 was L3The following is recorded: Resistances R2 and R3 are significantly higher than resistance R1 due to dry fumes. This is because, in the power control system, when a certain predetermined power is supplied to the heater and there is insufficient liquid aerosol-forming substrate present in the heater, for example, when the cartridge storing the liquid aerosol-forming substrate is empty, less power is consumed or no power is consumed in the vaporization of the liquid, resulting in a significant increase in the recorded resistance to the final temperature achieved. Furthermore, the temperature rises at a faster rate compared to when liquid is present, which is evident from the more rapid rate of temperature rise in the second and third inhalations.

[0093] The system is configured to detect this significant and abrupt increase in recorded resistance caused by insufficient fluid. Specifically, the system is configured to detect when the recorded resistance increases above a threshold. Upon detection, the system can isolate the heater to prevent further dry fume extraction, thereby reducing the possibility of the user being exposed to undesirable byproducts. Instructions to detect dry fume extraction and isolate the heater can be implemented in the software programmed within the controller.

[0094] Figure 8 shows a graph of resistance R versus time t and the heater temperature profile of an aerosol generating system according to another embodiment of the present invention where the heater exhibits a different dry inhalation condition. In particular, Figure 8 shows the first three inhalations or inhalations of a user's usage session, where the first inhalation is regulated by hybrid adjustment and subsequent inhalations are regulated by resistance adjustment.

[0095] In Figure 8, the system is activated at time t0, and the user begins the first inhalation or smoke extraction at time t1, which activates the heater. The first inhalation in Figure 8 is controlled in the same way as the first inhalation in Figure 7. During the first inhalation, liquid is present in the heater, which is initially controlled by the first control process or mode based on power adjustment. L1Upon detection of a predetermined condition, the resistance is recorded, and the target resistance R is determined based on the recorded resistance. T This is determined. At this point, the heater control switches to a second control step or mode based on resistance adjustment, which is used for the remaining inhalation until inhalation ends at time t2.

[0096] During the second and third inhalations, the amount of liquid aerosol generating substrate available for use by the heater is insufficient, resulting in dry fumes. In Figure 8, the second and third inhalations begin at times t3 and t5, respectively, at which point the heater is restarted, but controlled only by the second control step based on resistance adjustment, where the resistance is set to the target resistance R of the first inhalation until the inhalations end at times t4 and t6, respectively. T The system is adjusted to maintain a constant resistance during the second and third inhalations, so because the resistance is kept constant, it is not possible to detect dry inhalation conditions using changes in resistance. Instead, it is necessary to monitor the power required to maintain the target temperature and, therefore, the target resistance. When the liquid aerosol generating substrate is insufficient in the heater, no power is consumed in the vaporization of the liquid, so the power required to maintain a constant temperature is significantly lower than when liquid is present.

[0097] The system is configured to detect a significant decrease in the power required to maintain the heater at a target resistance. Specifically, the system is configured to detect when the power required to maintain the heater at the target resistance falls below a threshold. Upon detection, the system can isolate the heater to prevent further dry fume extraction, thereby reducing the user's potential exposure to undesirable byproducts. The commands to detect dry fume extraction and isolate the heater can be implemented in the software programmed within the controller.

[0098] Figure 9 illustrates a control circuit 200 used to provide temperature control according to one embodiment of the present invention.

[0099] Circuit 200 includes a heater 214 with a resistive heating element, connected to a power supply via connection 222. The power supply provides a voltage V2. An additional resistor 224 with a known resistance r is inserted in series with the heater 214. At a point in the circuit between the heater 214 and the additional resistor 224, i.e., on the ground side of the heater 214, there is a voltage V1. Voltage V1 is midway between ground and voltage V2. Software for providing temperature control is incorporated into the software programmed in the microcontroller 218, which can transmit a pulse-width modulated voltage signal to a transistor 226 via the output 230 of the microcontroller 218, which acts as a simple switch to activate the heater 214 according to the pulse-width modulated voltage signal.

[0100] The temperature indication of heater 214 (in this example, the electrical resistance of heater 214) is determined by measuring the electrical resistance of heater 214. The temperature indication is used to adjust the load cycle of the pulse-width modulated voltage supplied to heater 214 in order to keep the heater near the target resistance. The temperature indication is determined at a frequency chosen to match the timing required for the control process, and may be determined every 100 ms or more as needed.

[0101] Analog input 221 on the microcontroller 218 is used to monitor the voltage V2 on the power source side of the heater 214. Analog input 223 on the microcontroller is used to monitor the voltage V1 on the ground side of the heater 214.

[0102] The heater resistance measured at a specific temperature is R ヒーター The microprocessor 218 controls the resistor R of the heater 214. ヒーター To measure this, both the current flowing through heater 214 and the voltage across heater 214 can be determined. Then, Ohm's law can be used to determine the resistance. TIFF0007875343000001.tif11160

[0103] In Figure 9, the voltage across the heater is V2 to V1, and the current flowing through the heater is I. Therefore, TIFF0007875343000002.tif16160

[0104] Using an additional resistor 224 with a known resistance r, we again use (1) above to determine the current I. The current flowing through resistor 224 is also I, and the voltage across resistor 224 is V1. Therefore, TIFF0007875343000003.tif16160

[0105] Therefore, when (2) and (3) are combined, TIFF0007875343000004.tif16160

[0106] Therefore, since an aerosol generation system is used, the microprocessor 218 can measure V2 and V1, and also knows the value of r, and thus the heater resistance R at a specific temperature. ヒーター It is possible to make a decision.

[0107] Heater resistance R ヒーター It correlates with temperature. Using a linear approximation, the measured resistance R is calculated according to the following equation. ヒーター The corresponding temperature T can be determined. In formula TIFF0007875343000005.tif16160, A is the thermal resistance coefficient of the heater material, and R0 is the resistance of the heater at ambient temperature T0.

[0108] An advantage of control circuit 200 is that it does not require a temperature sensor. Such sensors can be bulky and expensive. Also, the microcontroller can directly use a resistance value instead of temperature. Heater resistance R ヒーターIf the temperature is maintained within the desired range, the temperature of the heater 214 will also be maintained within the desired range. As a result, the actual temperature of the heater 214 does not need to be calculated during the control process, which improves computational efficiency. However, if desired, it is possible to use a separate temperature sensor and connect it to the microcontroller to provide the necessary temperature information.

[0109] The software programmed into the microcontroller 218 is configured to monitor predetermined conditions and, when those conditions are detected, to record the heater resistance. The predetermined conditions and resistance can be stored in the microcontroller 218's memory. The software programmed into the microcontroller 218 is configured to determine a target resistance based on the recorded resistance.

[0110] The microcontroller 218 is also configured to adapt the load cycle of a pulse-width modulated voltage signal to control the power supplied to the heater in order to drive the heater's resistance toward a target resistance, so that the heater is driven toward a target temperature corresponding to the target resistance. To adjust the resistance, the heater resistor R ヒーター The heater resistance R was determined. ヒーター The error between the current resistance and the target resistance is calculated. Next, the power load cycle is adjusted using proportional-integral-derivative (PID) control to correct the error and drive the heater toward the target resistance. The PID control is incorporated into the software programmed into the controller 218.

[0111] The power P supplied to the heater 214 can be determined by the following formula. In formula TIFF0007875343000006.tif6160, V is the voltage across the heater, i.e., V2 to V1, and I is the current flowing through the heater, which can be determined using (3) above. The determined power can be used, for example, to detect the dry fume extraction situation shown in Figure 8.

Claims

1. A method for controlling heating in an aerosol generation system equipped with a heater, A first control step comprising supplying a predetermined power to the heater and determining the resistance of the heater, wherein the determined resistance indicates the temperature of the heater, A step of monitoring predetermined conditions and recording the resistance of the heater upon detection of the predetermined conditions, A step of determining a target resistance corresponding to the target temperature of the heater based on the recorded resistance, The second control step includes, so that the heater is driven toward a target temperature corresponding to the target resistance, the power supplied to the heater is adapted in a controllable manner to drive the resistance of the heater toward the target resistance, A method wherein only the first control step and the step of monitoring and detecting predetermined conditions and recording the resistance are performed during a plurality of initial user inhalations.

2. The aforementioned predetermined conditions ●Time elapsed since the start of user inhalation, ●The derivative of the resistor is below a predetermined threshold, ● The method according to claim 1, selected from one or more of the following: the derivative of the resistance, which is equal to zero.

3. The method according to claim 1, wherein the target resistance is determined after the plurality of initial user inhalations.

4. The method according to any one of claims 1 to 3, wherein the target resistance is determined based on the average of the recorded resistances from the plurality of initial user inhalations.

5. The method according to claim 4, wherein the user inhalations after the plurality of initial user inhalations use only the second control step, and the target resistance is based on the average of the recorded resistances from the plurality of initial user inhalations.

6. an aerosol generation system, A heater and Power supply and A controller is provided, and the controller is A predetermined power is supplied to the heater, and the resistance of the heater is determined in the first control mode, and the determined resistance indicates the temperature of the heater. The system monitors predetermined conditions and, upon detection of the predetermined conditions, records the resistance of the heater. Based on the recorded resistance, a target resistance corresponding to the target temperature of the heater is determined. In a second control mode, the power supplied to the heater is configured to be controllably adapted to drive the resistance of the heater toward the target resistance, so that the heater is driven toward a target temperature corresponding to the target resistance. An aerosol generating system in which only the first control mode, as well as the monitoring and detection of predetermined conditions and the recording of resistance, are used during multiple initial user inhalations.

7. The aforementioned predetermined conditions ●Time elapsed since the start of user inhalation, ●The derivative of the resistor is below a predetermined threshold, ● An aerosol generating system according to claim 6, selected from one or more of the following: the derivative of resistance equal to zero, and

8. The aerosol generating system according to claim 6, wherein the target resistance is determined after the plurality of initial user inhalations.

9. The aerosol generating system according to any one of claims 6 to 8, wherein the target resistance is determined based on the average of the recorded resistances from the plurality of initial user inhalations.

10. The aerosol generating system according to claim 9, wherein the user inhalations after the plurality of initial user inhalations use only the second control mode, and the target resistance is based on the average of the recorded resistances from the plurality of initial user inhalations.

11. A controller for an aerosol generating system, wherein the controller is configured to perform the method according to any one of claims 1 to 5.

12. A computer program that, when executed on a programmable controller for an aerosol generating system, causes the programmable controller to perform the method according to any one of claims 1 to 5.

Images