• 专利附录
  • 专利说明
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    • 专利摘要:
    a control unit (1) for an aerosol generating device (2), the aerosol generating device (2) comprising a resistive heater (3) and a battery (4), wherein the battery (4) is configured to generate a battery voltage (vbat), wherein said control unit (1) comprises: a dc / dc converter (11) arranged to receive the battery voltage (vbat) from the battery as input and to emit a voltage of outlet (heater) for the resistive heater (3); a microcontroller (12) configured to control said dc / dc converter (11) to adjust the output voltage based on a predetermined temperature profile for the resistive heater (3). the use of a dc / dc converter to adjust the dc voltage applied to the resistive heater has significant advantages over using only pulse width modulation (pwm), especially when the resistive heater mass is low.
    公开号:BR112019020434A2
    申请号:R112019020434
    申请日:2018-04-12
    公开日:2020-04-22
    发明作者:Robert Jacques；Christian Courbat Jerome；Bessant Michel
    申请人:Philip Morris Products Sa；
    IPC主号:
    专利说明:

    Descriptive Report of the Invention Patent for SYSTEM AND METHOD FOR TEMPERATURE CONTROL IN AN ELECTRICALLY HEATED AEROSOL GENERATOR DEVICE.
    [001] The invention relates to heated aerosol generating devices and, particularly, to the temperature control of a heater within a battery powered aerosol generating device.
    [002] Typically, in a heated and battery powered aerosol generating device, an electrically resistive heating element is used to heat an aerosol-forming substrate. The aerosol-forming substrate comprises one or more volatile compounds that are vaporized by the resistive heating element and then cooled to form an aerosol. The temperature of the resistive heating element plays a significant role in determining the quantity and quality of the aerosol produced. Therefore, there is a need for such devices to provide temperature control of the heating elements within the device.
    [003] In addition, it is desirable to be able to control the temperature of the heating element to follow a specific temperature profile over time. Changes in the conditions of the aerosol-forming substrate and changes in airflow through the device may mean that simply controlling the heating element to be at a single target temperature does not provide ideal results.
    [004] Normally, pulse width modulation (PWM) of the voltage supplied to the heating elements is used to control the temperature of the heating element. This provides simple and highly reactive control of the heating element temperature. However, there are several limitations
    Petition 870190097361, of 09/30/2019, p. 16/55
    2/27 tions on using pulse width modulation as the only method for temperature control. It would be desirable to provide an alternative method and system for controlling the temperature of a heating element within an aerosol generating system.
    [005] In a first aspect of the invention, a control unit is provided for an aerosol generating device, the aerosol generating device comprising a resistive heater for heating an aerosol forming substrate and a battery, wherein the battery is configured to generate a battery voltage, in which said control unit comprises:
    a DC / DC converter arranged to receive the battery voltage as an input from the battery and output an output voltage to the resistive heater; and a microcontroller configured to control said DC / DC converter to adjust the output voltage based on a predetermined temperature profile for the resistive heater.
    [006] The use of a DC / DC converter to adjust the DC voltage applied to the resistive heater has significant advantages over the use of pulse width modulation (PWM) only, especially when the resistive heater mass is low. Although PWM control is relatively simple and inexpensive to implement and highly reactive, there is a danger in PWM control that a resistive heater overheats during periods when it is ON, if the mass of the resistive heater structure is not is sufficient to effectively calculate the average temperature between the off and on periods (ON and OFF). It is not desirable to simply increase the frequency of PWM to mitigate this problem, because the efficiency of the device will decrease when the frequency of PWM becomes too high. Likewise, the increase in the mass of the heater structure by incorporating a large transfer structure
    Petition 870190097361, of 09/30/2019, p. 17/55
    3/27 heat transfer between the resistive heating elements and the aerosol forming substrate to reduce temperature spikes in the aerosol forming substrate causes its own problems. If the mass of the heater structure is too large, the heater will take a long time to warm up to the required operating temperature.
    [007] Therefore, it can be very difficult to find the right balance between the PWM control parameters and the resistive heater structure. The use of PWM control effectively limits the design freedom of the heater structure.
    [008] On the other hand, the use of a DC / DC converter to control the voltage applied to the resistive heater according to a target temperature profile allows for much greater flexibility in the heater design and particularly allows for a low heater mass.
    [009] There is another problem with PWM control when used with resistive heaters that have a low electrical resistance when they are cold. PWM means that the total battery voltage is supplied during the connected periods. At low temperature, when the device is turned on for the first time, there is low resistance of the heater and therefore a high current, which the battery may not be able to supply, especially when the battery is cold as well. This can lead to complete device failure.
    [0010] The use of a DC / DC converter allows the control of the voltage through the heater and, thus, the control of the maximum current extracted from the battery.
    [0011] As used in this document, the term DC / DC converter means an electronic circuit or electromechanical device that converts a direct current source (CD) from one voltage level to another. The DC / DC converter can be, for example, a buck converter, a boost converter or a buck-boost converter. The DC / DC converter
    Petition 870190097361, of 09/30/2019, p. 18/55
    4/27 can comprise more than one phase of the energy converter. Advantageously, the DC / DC converter is a programmable DC / DC converter.
    [0012] The control unit can also comprise a digital potentiometer connected between the microcontroller and the DC / DC converter. The digital potentiometer can be used to set the output voltage of the DC / DC converter. The digital potentiometer can be programmable.
    [0013] The control unit can also comprise a non-volatile memory that stores the predetermined temperature profile or the electrical resistance profile. The predetermined temperature or voltage profile can be stored in a look-up table. The memory can store other query tables or routines related to the parameters of the heater or the DC / DC converter among themselves.
    [0014] Advantageously, the microcontroller is configured to control said DC / DC converter based on a measured or calculated resistance or temperature of the resistive heater. In one embodiment, the electrically resistive heater has an electrical resistance that depends on its temperature. In that case, the microcontroller can be configured to control said DC / DC converter based on a calculated electrical resistance of the electrically resistive heater. The control unit can be configured to calculate the electrical resistance of the electrically resistive heater from voltage and current measurements.
    [0015] In another mode, the control unit can comprise a temperature sensor connected to the microcontroller and positioned next to the electrically resistive heater. In that case, the microcontroller can be configured to control said DC / DC converter based on the signals from the temperature sensor.
    [0016] The microcontroller can be configured to operate a
    Petition 870190097361, of 09/30/2019, p. 19/55
    5/27 closed circuit control scheme. The closed-loop control scheme can be implemented as a routine in the microcontroller firmware. A closed-loop control scheme may be appropriate to control the heater temperature over a relatively long period of, for example, a few minutes, as required in continuously heated aerosol generating systems. The closed-loop control scheme can be arranged to control the DC / DC converter to adjust the temperature of the electrically resistive heater towards a target temperature. The target temperature can vary over time, according to a stored target temperature profile. The target temperature profile can be converted to a target resistance profile based on an electrically resistive heater resistance temperature coefficient. The control unit can store the target resistance profile in a non-volatile memory or it can generate the target resistance profile from a target temperature profile stored in a non-volatile memory.
    [0017] The microcontroller can be configured to operate as a proportional integral derivative controller (PID) to adjust the temperature of the electrically resistive heater towards a target temperature in a closed circuit control scheme. Alternatively, the microcontroller can be configured to use predictive logic to adjust the temperature of the electrically resistive heater towards a target temperature in a closed-loop control scheme.
    [0018] Alternatively, the microcontroller can be configured to operate a closed circuit control scheme. In this case, the control unit can store a target profile for a control value input in the DC / DC converter. The control value can determine the Heater output level of the DC / DC converter. O
    Petition 870190097361, of 09/30/2019, p. 20/55
    6/27 microcontroller can be configured to provide said DC / DC converter with a control value according to the target profile for the control value. An open circuit control scheme may be appropriate to control the electrically resistive heater for relatively short periods of time, such as a few seconds, in a drag-powered aerosol generator system in which the heater is supplied with power only during user puffs .
    [0019] The microcontroller can also be configured to adjust the average current supplied to the resistive heater of the DC / DC converter, by controlling the operation of a switch connected in series with the resistive heater and the DC / DC converter. The microcontroller can be configured to use the switch's pulse width modulation control. Therefore, the microcontroller can be configured to operate a PWM control scheme, in addition to controlling using the DC / DC converter. Basic temperature control can be performed using the DC / DC converter and, as it provides a faster response, the PWM control scheme can be used to adjust the temperature.
    [0020] The microcontroller can be configured to monitor a current through the resistive heater and control the DC / DC converter to ensure that the current through the resistive heater does not exceed a maximum current limit. This avoids overcharging the battery, which can cause the device to fail.
    [0021] The microcontroller can control the DC / DC converter to ensure that the battery voltage is maintained at or above the minimum battery voltage. The minimum battery voltage can be a minimum voltage required for the operation of specific components within the device, such as the microcontroller. This ensures that the components, and particularly the microcontroller, are always ready for operation.
    Petition 870190097361, of 09/30/2019, p. 21/55
    7/27 [0022] Alternatively or additionally, the device may comprise a second voltage source for the microcontroller. The second voltage source can be a second battery or it can be a voltage regulator, such as a second DC / DC converter or a linear dropout regulator, LDO, connected between the battery and the microcontroller. This can be used to ensure that the microcontroller and other electronic components receive the minimum voltage required.
    [0023] The microcontroller can be any suitable microcontroller, but it is preferably programmable.
    [0024] In a second aspect of the invention, an aerosol generating device for generating the inhalable aerosol is provided, the device comprising:
    a resistive heater for heating an aerosol-forming substrate, a battery, in which the battery is configured to generate battery voltage and a control unit according to the first aspect of the invention.
    [0025] The aerosol generating device can be configured to receive an aerosol-forming substrate.
    [0026] The resistive heater may comprise an electrically resistive material. Suitable electrically resistive materials include, but are not limited to: semiconductors, such as doped ceramics, electrically conductive ceramics (such as, for example, molybdenum disilicate), carbon, graphite, metals, metal alloys and composite materials made of a material ceramic and metallic material. Such composite materials may comprise doped or non-doped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of me
    Petition 870190097361, of 09/30/2019, p. 22/55
    Such suitable 8/27 include titanium, zirconium, tantalum, platinum, gold and silver. Examples of suitable metal alloys include stainless steel, alloys containing nickel, cobalt, chromium, aluminum, titanium, zirconium, hafnium, niobium, molybdenum, tantalum, tungsten, tin, gallium, manganese, gold and iron, and nickel-based super alloys. iron, cobalt, stainless steel, Timetal® and alloys based on iron, manganese and aluminum. In composite materials, the electrically resistive material can optionally be incorporated, encapsulated or coated with insulating material or vice versa, depending on the power transfer kinetics and the required external physiochemical properties.
    [0027] The aerosol generating device may comprise an internal resistive heater or an external resistive heater or both, where internal and external refer to the aerosol-forming substrate. An internal resistive heater can take any suitable shape. For example, an internal resistive heater may take the form of a heating blade. Alternatively, the internal resistive heater can take the form of a coating or substrate with different electroconductive portions or an electrically resistive metal tube. As another option, an internal resistive heater can be one or more heating needles or columns that pass through the center of the aerosol-forming substrate. Other alternatives include a heating wire or filament, for example, a Ni-Cr (nickel-chromium) wire, platinum, tungsten or alloy wire, or a heating plate. Optionally, the internal resistive heater can be placed inside or on a rigid transport material. In such an embodiment, the internal resistive heater can be formed using a metal that has a defined relationship between temperature and resistivity. In an example of such a device, the metal can be formed as a strip of a suitable insulating material, such as a ceramic material and then placed between another material
    Petition 870190097361, of 09/30/2019, p. 23/55
    9/27 insulating, like glass. Heaters formed in this way can be used both to heat and to monitor the temperature of the heating elements during operation.
    [0028] An external resistive heater can take any suitable shape. For example, an external resistive heater may take the form of one or more flexible heating sheets on a dielectric substrate, such as polyimide. The flexible heating sheets can be shaped to fit the perimeter of the substrate receiving cavity. Alternatively, an external heating element can take the form of one or more metal grids, a flexible printed circuit board, a molded interconnect device (MID), ceramic heater, flexible carbon fiber heater, or it can be formed using a coating technique, such as plasma vapor deposition, on a suitable substrate. Other techniques, such as evaporation, chemical engraving, laser engraving, screen printing, gravure printing and inkjet printing can also be used to form the heater. An external resistive heater can also be formed using a metal that has a definite relationship between temperature and resistivity. In an example of such a device, the metal can be formed as a strip between two layers of suitable insulating materials. An external resistive heater formed in this way can be used both to heat and to monitor the temperature of the external heating element during operation.
    [0029] The resistive heater advantageously heats the aerosol-forming substrate by means of conduction. The resistive heater can be at least partially in contact with the substrate or with the conveyor on which the substrate is deposited. Alternatively, the heat from an internal or external element can be conducted to the
    Petition 870190097361, of 09/30/2019, p. 24/55
    10/27 substrate by means of a heat conducting element.
    [0030] The resistive heater can have a mass between 0.1 g and 0.5 g and more preferably between 0.15 g and 0.25 g. The battery can be a rechargeable battery. The battery can be a lithium-ion battery, for example, lithium-cobalt, lithium-iron-phosphate, lithium titanate or a lithium polymer battery. Alternatively, the battery can be another form of rechargeable battery, such as a nickel-metal hydride battery or a nickel-cadmium battery.
    [0031] The microcontroller can be configured to continuously supply current to the resistive heater of the DC / DC converter for a period of more than 5 seconds. The microcontroller can be configured to control the DC / DC converter based on a target temperature profile that varies with time after activation of the device.
    [0032] As used in this document, an aerosol generating device refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-forming substrate may be part of an aerosol-generating article. An aerosol generating device may be a device that interacts with an aerosol-forming substrate of an aerosol-generating article to generate an aerosol that is directly inhaled into a user's lungs through the user's mouth. The aerosol-forming substrate may be wholly or partially contained in the device.
    [0033] The aerosol forming substrate can be a solid aerosol forming substrate. Alternatively, the aerosol-forming substrate may be a liquid or may comprise solid and liquid components. The aerosol-forming substrate may comprise a tobacco-containing material, containing volatile tobacco flavoring compounds, which are released from the substrate upon heating. Alternatively, the aerosol-forming substrate may comprise
    Petition 870190097361, of 09/30/2019, p. 25/55
    11/27 a material without tobacco. The aerosol forming substrate may further comprise an aerosol former. Examples of suitable aerosol builders are glycerin and propylene glycol.
    [0034] If the aerosol-forming substrate is a solid aerosol-forming substrate, the aerosol-forming substrate may comprise, for example, one or more of these: powder, granules, pellets, pieces, filaments, strips or sheets containing one or more of these: herbal leaf, tobacco leaf, tobacco twig fragments, reconstituted tobacco, homogenized tobacco, extruded tobacco, reconstituted tobacco and expanded tobacco. The solid aerosol-forming substrate may be in loose form or may be supplied in a suitable container or cartridge. Optionally, the solid aerosol-forming substrate may contain additional volatile tobacco flavoring compounds or no tobacco, to be released upon heating the substrate. The solid aerosol-forming substrate may also contain capsules which, for example, include the additional volatile tobacco flavoring compounds or non-tobacco, and such capsules may melt while heating the solid aerosol-forming substrate.
    [0035] Optionally, the solid aerosol forming substrate can be supplied or incorporated into a thermally stable carrier. The carrier can take the form of powder, granules, pellets, filaments, pieces, strips or sheets. Alternatively, the carrier may be a tubular carrier and contain a thin layer of the solid substrate deposited on its inner or outer surface or on its inner and outer surfaces. Such a tubular conveyor may be formed, for example, from paper, or paper-like material, a non-woven carbon fiber mat, a low-mass open-mesh wire mesh, a perforated metal sheet or any other thermally stable polymeric matrix .
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    12/27 [0036] The solid aerosol-forming substrate can be deposited on the surface of the carrier in the form of, for example, a sheet, foam, gel or paste. The solid aerosol-forming substrate can be deposited over the entire carrier surface or, alternatively, can be deposited in a pattern to provide non-uniform aroma distribution during use.
    [0037] Although reference has been made to solid aerosol-forming substrates earlier in this disclosure, it will be apparent to one skilled in the art that other forms of aerosol-forming substrate can be used with other modalities. For example, the aerosol forming substrate can be a liquid aerosol forming substrate. If a liquid aerosol forming substrate is provided, the aerosol generating device preferably comprises means for retaining the liquid. For example, the liquid aerosol-forming substrate can be retained in a container. Alternatively or in addition, the liquid aerosol-forming substrate can be absorbed into a porous carrier material. The porous carrier material can be made of any suitable plug or absorbent body, for example, a metal foam or plastic foam material, polypropylene, terylene, nylon or ceramic fibers. The liquid aerosol-forming substrate may be retained in the porous carrier material prior to use of the aerosol-generating device or, alternatively, the material of the liquid aerosol-forming substrate may be released into the porous carrier material during or immediately before use. For example, the liquid aerosol-forming substrate can be supplied in a capsule. The cartridge of the capsule preferably melts upon heating releasing the liquid aerosol-forming substrate into the porous carrier material. The capsule can optionally contain a solid in combination with the liquid. Alternatively, the carrier can be
    Petition 870190097361, of 09/30/2019, p. 27/55
    13/27 a non-woven fabric or bundle of fibers in which tobacco components have been incorporated. The non-woven fabric or bundle of fibers may comprise, for example, carbon fibers, natural cellulose fibers or fibers derived from cellulose.
    [0038] During operation, the aerosol-forming substrate can be completely contained within the aerosol generating device. In this case, a user may swallow through the mouthpiece of an aerosol generating device. Alternatively, during operation, an aerosol forming article containing the aerosol forming substrate may be partially contained within the aerosol generating device. In this case, the user can swallow directly in the aerosol-forming article.
    [0039] The aerosol forming article can be substantially cylindrical in shape. The aerosol-forming article can be substantially elongated. The aerosol forming article may have a length and circumference substantially perpendicular to the length. The aerosol-forming substrate can be substantially cylindrical in shape. The aerosol-forming substrate can be substantially elongated. The aerosol-forming substrate can also have a length and circumference substantially perpendicular to the length.
    [0040] For example, the aerosol forming article can have a total length between approximately 30 mm and approximately 100 mm. The aerosol forming article can have an outside diameter between approximately 5 mm and approximately 12 mm. The aerosol forming article may comprise a filter plug. The filter plug may be located at the downstream end of the aerosol forming article. The filter plug can be a cellulose acetate filter plug. The filter plug is approximately 7 mm long, in one mode, but may have a length of 870190097361, from 09/30/2019, pg. 28/55
    14/27 between approximately 5 mm and approximately 10 mm.
    [0041] In one embodiment, the aerosol-forming article has a total length of approximately 45 mm. The aerosol forming article may have an outside diameter of approximately 7.2 mm. In addition, the aerosol-forming substrate may be approximately 10 mm long. Alternatively, the aerosol-forming substrate may be approximately 12 mm long. In addition, the diameter of the aerosol-forming substrate can be between approximately 5 mm and approximately 12 mm. The aerosol-forming article may comprise an outer paper wrapper. In addition, the aerosol forming article may comprise a separation between the aerosol forming substrate and the filter plug. The separation can be about 18 mm, but it can be in the range of about 5 mm and about 25 mm.
    [0042] The device is preferably a portable or handheld device, which can be held comfortably between the fingers of a hand. The device can be basically cylindrical in shape and have a length of 70 to 200 mm. The maximum diameter of the device is preferably between 10 and 30 mm. In one embodiment, the device has a polygonal cross section and a button protruding from one side. In this embodiment, the diameter of the device is between 12.7 and 13.65 mm measured from a flat face to an opposite flat face; between 13.4 and 14.2 measured from one edge to an opposite edge (that is, from the intersection of two faces on one side of the device to a corresponding intersection on the other side), and between 14.2 and 15 mm measured from one top of the button to an opposite flat bottom face.
    [0043] In a third aspect of the invention, a method is provided for controlling an aerosol generating device, the aerosol generating device comprising a resistive heater, a battery
    Petition 870190097361, of 09/30/2019, p. 29/55
    15/27 ria, in which the battery is configured to generate a battery voltage and a control unit, the control unit comprising a DC / DC converter arranged to receive the battery voltage from the battery as input and emit a voltage output to the resistive heater, the method comprising:
    [0044] control said DC / DC converter to adjust the output voltage based on a predetermined temperature profile for the resistive heater.
    [0045] Advantageously, the method may comprise the control of said DC / DC converter based on a measured or calculated resistance or temperature of the resistive heater. In one embodiment, the electrically resistive heater has an electrical resistance that depends on its temperature. In this case, the method can comprise the control of said DC / DC converter based on a calculated electrical resistance of the electrically resistive heater. The method can also include the calculation of the electrical resistance of the electrically resistive heater based on voltage and current measurements.
    [0046] The method can comprise the operation of a closed circuit control scheme. The closed-loop control scheme can be implemented as a routine in the microcontroller firmware. A closed-loop control scheme may be appropriate for controlling the heater temperature over a relatively long period of, for example, a few minutes, as required in continuously heated aerosol generating systems. The closed-loop control scheme can be arranged to control the DC / DC converter to adjust the temperature of the electrically resistive heater towards a target temperature. The target temperature can vary over time, according to a stored target temperature profile. The target temperature profile can be converted to a target resistance profile based on a coefficient
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    16/27 aware of the resistance temperature of the electrically resistive heater.
    [0047] The method can comprise the operation of a derivative integral proportional controller (PID) to adjust the temperature of the electrically resistive heater towards a target temperature in a closed circuit control scheme. Alternatively, the method may comprise the use of predictive logic to adjust the temperature of the electrically resistive heater towards a target temperature in a closed-loop control scheme.
    [0048] Alternatively, the method may comprise the operation of an open circuit control scheme. An open circuit control scheme may be appropriate for controlling the electrically resistive heater for relatively short periods of time, such as in a drag-powered aerosol generator system in which the heater is supplied with power only during user puffs.
    [0049] The method may also include adjusting the average current supplied to the resistive heater of the DC / DC converter by controlling the operation of a switch connected in series with the resistive heater and the DC / DC converter. The method may comprise the operation of the switch to provide pulse width modulation of the current supplied to the resistive heater. This technique can be used to fine-tune the voltage control provided by the DC / DC converter.
    [0050] The method can comprise monitoring a current through the resistive heater and controlling the DC / DC converter to ensure that the current through the resistive heater does not exceed a maximum current limit. This avoids overcharging the battery, which can cause the device to fail.
    [0051] The method can comprise the control of the converter
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    17/27
    DC / DC to ensure that the battery voltage is maintained at or above the minimum battery voltage. The minimum battery voltage can be a minimum voltage required to operate specific components within the device, such as a microcontroller. Alternatively or additionally, the method may comprise operating a second voltage source for the microcontroller. The second voltage source can be a second battery or it can be a voltage regulator, such as a second DC / DC converter or a low dropout regulator, LDO, connected between the battery and the microcontroller.
    [0052] In a fourth aspect of the invention, a computer program is provided which, when executed on programmable electrical circuits in a control unit of an electrically operated aerosol generating device, the aerosol generating device comprising a resistive heater, a battery , where the battery is configured to generate a battery voltage and a control unit, the control unit comprising a DC / DC converter arranged to receive the battery voltage from the battery as input and output an output voltage to the resistive heater, causes the programmable electrical circuit to perform a method according to the third aspect of the invention.
    [0053] Although the present disclosure has been described as a reference to different aspects, it must be made clear that the characteristics described in relation to one aspect of the present disclosure can be applied to the other aspects of the disclosure. In particular, aspects described in relation to the first aspect of the invention may be applicable to the second and third aspects of the invention.
    [0054] Examples of the invention will then be described in detail with reference to the attached drawings in which:
    [0055] Figure 1 shows a schematic illustration of a provision 870190097361, of 09/30/2019, p. 32/55
    18/27 positive according to an additional embodiment of the invention;
    [0056] Figure 2 is a schematic diagram that illustrates the device components involved in controlling the heater temperature;
    [0057] Figure 3 illustrates an example of a temperature profile for the resistive heater and corresponding profiles of resistance and voltage generated;
    [0058] Figure 4 illustrates a PID-based control circuit for the heater voltage;
    [0059] Figure 5 illustrates a control circuit using predictive logic for the heater voltage; and [0060] Figure 6 illustrates another example of a temperature profile for the resistive heater and a corresponding voltage profile, suitable for a device that activates the heater only during the user's inhalations.
    [0061] In Figure 1, the components of an embodiment of an electrically heated aerosol generating device 1 are shown in a simplified form. The elements of the electrically heated aerosol generating device 1 are not drawn to scale in Figure 1. Elements that are not relevant for understanding this modality have been omitted to simplify Figure 1.
    [0062] The electrically heated aerosol generating device 1 is formed by a compartment 10 and an aerosol forming substrate 12, for example an aerosol forming article such as a cigarette. The aerosol-forming substrate 12 is pushed into the compartment 10 to be in thermal proximity to the heater 4. In this example, the heater is a blade that extends to the aerosol-forming substrate. The aerosol-forming substrate 12 will release a variety of volatile compounds at different temperatures. By controlling the heater's operating temperature
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    19/27 to be below the release temperature of some of the volatile compounds, the release or formation of these smoke constituents can be prevented. Normally, the aerosol-forming substrate is heated to a temperature between 170 and 450 degrees centigrade. In one embodiment, the aerosol-forming substrate is heated to a temperature between 170 and 250 degrees centigrade and, preferably, between 180 and 240 degrees centigrade. In another embodiment, the aerosol-forming substrate is heated to a temperature between 240 and 450 degrees centigrade and, preferably, between 250 and 350 degrees centigrade. Inside compartment 10 there is a battery 2, for example, a rechargeable lithium ion battery. A control unit 3 is connected to the heating element 4, the electric battery 2 and a user interface 6, for example, a button or display. This type of system is described in EP2800486, for example.
    [0063] The control unit 3 controls the energy supplied to the heating element 4, to regulate its temperature. It may be desirable to vary the temperature over a single use of the device. In one example, it is desirable to increase the temperature quickly immediately after activating the device to minimize the time required for a first puff to be available and then to reduce the temperature of the heater so that the substrate is kept at a constant temperature by next puffs. It may then be desirable to increase the temperature of the heater as the aerosol-forming substrate runs out, to ensure that sufficient aerosol is still delivered to the user. This type of heating profile is described in detail in WO2014 / 102091.
    [0064] Figure 2 illustrates the components of the device involved in controlling the heater temperature. In particular, Figure 2 shows the arrangement of the battery 2, control unit 3 and heater 4. The
    Petition 870190097361, of 09/30/2019, p. 34/55
    The control unit 20/27 comprises a microcontroller 30 and a digitally controlled DC / DC converter 32. The digitally controlled DC / DC converter 32 is connected between battery 2 and heater 4 and is controlled by microcontroller 30. The DC / DC converter receives the battery output voltage (Vbat) at its input and emits an output voltage (Heater). In this example, the DC / DC converter is a buck or step-down converter, so that the Heater is less than or equal to the Vbat. But the invention can be implemented using, for example, a boost converter or a buck-boost converter or a combination of phases of the energy converter.
    [0065] The heater 4 comprises a plurality of electrically resistive bands on a substrate. The heater strips can be formed from platinum and the substrate can be a ceramic material, such as zirconia. The substrate is shaped like a blade to allow it to easily penetrate and be removed from an aerosol-forming substrate.
    [0066] The microcontroller controls the digitally controlled DC / DC converter so that the heater follows the desired temperature profile. In this mode, a closed-loop control scheme is used based on the resistance of the heater. The electrical resistance of the platinum heater bands is directly related to the heater temperature by the platinum resistance temperature coefficient. The microcontroller receives a measurement from the Heater and a measurement of the current through the heater. A current measurement block 34 is shown connected between the heater and the earth, with an output connected to the microcontroller 30. The current measurement block 34 can comprise a branch resistor (with a very low resistance) in series with the heater 4. The current through the shunt resistor, which is also the current through the heater, can be measured using a connected amplifier.
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    21/27 in parallel to the bypass resistor. The resistance of the heater was calculated using Ohm's law.
    [0067] Referring to Figure 3, the microcontroller stores a desired temperature profile, illustrated in graph 40 and stored as a query table 41. Graph 40 illustrates the target temperature of the heater versus the time after activation of the device. In this example, the temperature profile comprises five distinct phases. In a first stage, the heater is raised from an ambient temperature TO to an initial target temperature T1. This first phase lasts for 30 seconds. In a second phase, lasting one minute, the heater temperature is maintained at T1. In a third phase, the temperature drops and is maintained at a second target temperature T2. The third phase lasts for two minutes. In a fourth phase, lasting 20 seconds, the temperature is gradually increased to a third target temperature T3. In a final phase of 2 more minutes, the heater is maintained at a temperature of T3. After the final phase, the heater power is turned off.
    [0068] To execute a closed loop control scheme based on this temperature profile, the microcontroller converts the target temperature profile into a corresponding target electrical resistance profile, based on the relationship between temperature and electrical resistance of the heater. The resistance profile is illustrated as graph 42 and as query table 43. A query table 44 can be stored in the microprocessor to convert the temperature profile into an electrical resistance profile.
    [0069] It is not always necessary to store a desired temperature profile in the form of temperature values. In some embodiments, it may be beneficial to store a desired electrical resistance profile. This is a temperature profile, simply converted to a resistance profile before being stored in the device.
    Petition 870190097361, of 09/30/2019, p. 36/55
    22/27
    If the heater is not replaceable, it may be preferable to store a resistance profile, as it reduces data storage requirements and processing steps in the device. However, especially if the heater is replaceable, it can be beneficial to store a temperature profile in the device and then convert it to a resistance profile in the device, as it is the temperature that must finally be controlled. When a heater is replaced, the new heater may have a different temperature coefficient of resistance than the previous heater.
    [0070] The closed loop control scheme is then used to bring the heater resistance towards the target resistance. The resulting Vaporizer voltage output is illustrated in graph 46.
    [0071] Figure 4 illustrates a first example of a closed-loop control scheme that can be implemented by the microprocessor. In a first step 50, the current measurement through the heater and the measurement from the Heater are received. In a second step 52, measurements are used to calculate the electrical resistance of the heater. The calculated resistance of the heater is compared to the target resistance in step 53 and the difference is output to a proportional integral derivative controller (PID) in step 54. The output of the PID controller is a value necessary for the Heater to bring the electrical resistance of the heater to target resistance. The use of a PID controller is a well-known technique for closed-loop control. The PID controller has fixed parameters, regardless of the heater temperature or resistance. Before the PID controller output is used to control the DC / DC converter, it is first checked whether the current or voltage through the heater or the required output of the DC / DC converter is greater than the predetermined maximum limits. If the current through the heater is greater than the maximum current that the battery can supply, in the step
    Petition 870190097361, of 09/30/2019, p. 37/55
    23/27 the necessary value for the Heater will be defined as the product of the maximum allowed current and the calculated resistance of the heater. If the Heater value calculated by the PID controller is greater than that provided by the DC / DC converter, the Heater will be set to the maximum output voltage of the DC / DC converter.
    [0072] The digitally controlled DC / DC converter includes a programmable DC / DC converter and a digital potentiometer. The microcontroller is connected to the digital potentiometer and is the digital potentiometer that defines the output voltage of the programmable DC / DC converter. The DC / DC feedback pin of the DC / DC converter is connected to the digital potentiometer and it is the value of that feedback pin that determines the output level of the Heater of the DC / DC converter. Referring again to Figure 3, the voltage profile shown in graph 46 is converted into a value to be applied to the DC / DC feedback pin using lookup table 48. Lookup table 48 can relate the Heater to a value to be applied to the DC / DC feedback pin in 0.05V steps, for example. By changing the value of the digital potentiometer, the CC / CC automatically adjusts the value of the Heater to the desired level. With this arrangement, it is possible to adjust the Heater value in less than 10 milliseconds. The digital potentiometer is controlled by the microcontroller through a Peripheral Serial Interface (SPI) in this example, but it can also be controlled by I2C or a parallel bus, for example.
    [0073] Figure 5 illustrates an alternative example of a closed-loop control scheme that can be implemented by the microprocessor. In a first step 60, the current measurement through the heater and the measurement of the Heater are received and then a second step 62 is used to calculate the electrical resistance of the heater. The calculated resistance of the heater is compared to the target resistance in step 63 and the difference is emitted
    Petition 870190097361, of 09/30/2019, p. 38/55
    24/27 for a predictive logic controller in step 64. The predictive logic controller can be based on an ideal heater model or behavior based on a plurality of parameters, such as Heater temperature, time current and error between target resistance and the calculated resistance. As in the control circuit of Figure 4, before the output of the predictive logic controller is used to control the DC / DC converter, it is first checked whether the current or voltage through the heater or the required output of the DC / DC converter is greater than the predetermined maximum limits. If the current through the heater is greater than the maximum current that the battery can supply, in step 65 the value required for the Heater will be defined as the product of the maximum allowed current and the calculated resistance of the heater. If the Heater value calculated by the predictive logic controller is greater than that provided by the DC / DC converter, then the Heater will be set to the maximum output voltage of the DC / DC converter.
    [0074] It can be seen that the control of the DC / DC converter can be done to ensure that the current does not exceed a maximum allowed current above which the battery would be overloaded and which can cause the device to fail. The control unit can also ensure that the microcontroller always receives enough voltage from the battery. A microcontroller usually requires a minimum voltage to operate, such as 2.5 volts.
    [0075] It is desirable to raise the heater to the first target temperature quickly so that the user does not have to wait long before a first puff. The greater the energy applied to the heater, the faster its temperature will increase. When the device is activated for the first time, the heater is normally at room temperature. For a heater with a positive temperature coefficient, it means that it has an electrical resistance
    Petition 870190097361, of 09/30/2019, p. 39/55
    25/27 relatively low compared to its resistance during operation. At low temperature, the battery also has a lower output energy because its output voltage is reduced and because its internal resistance is increased, which reduces the output current. This combination of factors means that, at low temperatures, if the maximum energy is extracted from the battery, the battery voltage can be reduced to a level below the minimum operating voltage of the microcontroller.
    [0076] As illustrated in Figure 2, the device includes a voltage regulator 36 to regulate the voltage supplied from the battery to the microcontroller. The voltage regulator in this example is a linear drop regulator (LDO), but it can, for example, be a second DC / DC converter. The LDO in this example is configured to provide a stable 2.5V to the microcontroller at all times. However, if the battery voltage drops below 2.5V, the LDO will not function properly.
    [0077] This problem can be avoided by controlling the DC / DC converter during the first phase of the temperature profile. The microcontroller can be configured to continuously monitor the battery voltage and compare it to a reference voltage, normally 2.5V. If the battery voltage is higher than the reference voltage, the control signal changes the value of the digital potentiometer so that it increases the DC / DC output voltage. If the battery voltage is lower than the reference voltage, the control signal changes the value of the digital potentiometer so that it decreases the DC / DC output voltage. This corresponds to a controlled circuit system in which the DC / DC output voltage is always at the maximum value, which can be ensuring that the battery voltage never falls below the minimum voltage of 2.5V. This method provides the fastest heating of the heater for a certain temperature of the battery.
    Petition 870190097361, of 09/30/2019, p. 40/55
    26/27 [0078] In some embodiments, an open circuit control scheme for the DC / DC converter may be preferable. For example, the aerosol generating device in Figure 1 can work by supplying power to a heater only in response to user inhalation. Between user inhalation, energy is not supplied to the heater. In this case, the temperature profile of the heater is much lower, about 2 or 3 seconds. There is no need for a complex temperature profile. The heater must reach the vaporization temperature as soon as possible, keep it for 2 or 3 seconds and then switch off. A temperature profile of this type is shown in Figure 6 as graph 70. The relationship between temperature and heater resistance can be known or calibrated during manufacture and the temperature or resistance profile can be converted into a profile for the control value a be applied to the CC / DC feedback pin, as shown in graph 72. The profile is stored in a lookup table on the microcontroller. The microcontroller controls the DC / DC converter via the digital potentiometer directly in an open circuit. The microcontroller can still receive and monitor the Heater and current measurements to detect abnormal or fault conditions, such as an exhausted substrate.
    [0079] In addition to controlling the DC / DC converter in an open or closed loop control scheme, the microcontroller can use pulse width modulation (PWM) to adjust the heater temperature control. A switch, such as a MOSFET, can be connected in series to the heater and can be controlled by the microcontroller to modulate the current supplied to the heater. PWM can be used, for example, when the error between the resistance of the target heater and the calculated resistance of the heater is less than a threshold value. Alternatively or in addition, PWM can be used to provide fast response time, for example,
    Petition 870190097361, of 09/30/2019, p. 41/55
    27/27 when the temperature is rising too fast.
    [0080] The use of a DC / DC converter controlled according to a predetermined temperature or voltage profile has several advantages. The temperature profile of the heater is smoother than with PWM control and there is a much less chance that the heater will overheat instantly. The instantaneous current required from the battery, particularly immediately after activation of the device, is less than when using the PWM control, reducing the potential for low voltage battery problems at low temperatures. In addition, the use of a DC / DC converter allows much greater flexibility in the design of the heater. For example, if a boost DC / DC converter is used, a higher resistance heater can be used, which can mitigate the impact of other resistors on the system, such as parasitic resistors and contact resistors.
    权利要求:
    Claims (14)
    [1]
    1. Aerosol generating device (1) for generating inhalable aerosol, the device (1) characterized by the fact that it comprises:
    a resistive heater (4), a battery (2), in which the battery (2) is configured to generate a battery voltage (Vbat) and a control unit (3), in which said control unit (3) comprises:
    a DC / DC converter (32) arranged to receive the battery voltage (Vbat) from the battery as an input and emit an output voltage (Heater) to the resistive heater (4); and a microcontroller (30) configured to control said DC / DC converter (32) to adjust the output voltage based on a predetermined temperature profile for the resistive heater (4) that varies with time.
    [2]
    2. Aerosol generating device according to claim 1, characterized by the fact that it also comprises a memory that stores the predetermined temperature profile.
    [3]
    Aerosol generating device according to claim 1 or 2, characterized by the fact that the microcontroller is configured to control said DC / DC converter based on a measured or calculated resistance or temperature of the resistive heater.
    [4]
    4. Aerosol generating device according to claim 3, characterized by the fact that the microcontroller is configured to operate a closed-loop control scheme.
    [5]
    Aerosol generating device according to any one of claims 1 to 4, characterized in that it also comprises means for measuring the temperature or resistance of the heater.
    Petition 870190097361, of 09/30/2019, p. 9/55
    2/3 cedor.
    [6]
    6. Aerosol generating device according to claim 1, 2 or 3, characterized by the fact that the microcontroller is configured to operate a closed circuit control scheme.
    [7]
    Aerosol generating device according to any one of claims 1 to 6, characterized by the fact that the microcontroller is configured to adjust the average current supplied to the resistive heater of the DC / DC converter by controlling the operation of a switch connected in series with resistive heater and DC / DC converter.
    [8]
    Aerosol generating device according to any one of claims 1 to 7, characterized by the fact that it also comprises a digital potentiometer connected between the microcontroller and the DC / DC converter.
    [9]
    Aerosol generating device according to any one of claims 1 to 8, characterized in that the microcontroller is configured to monitor a current through the resistive heater and to control the DC / DC converter to ensure that the current through the heater resistive does not exceed a maximum current limit.
    [10]
    Aerosol generating device according to any one of claims 1 to 9, characterized by the fact that the microcontroller controls the DC / DC converter to ensure that the battery voltage is maintained at or above the minimum battery voltage.
    [11]
    Aerosol generating device according to any one of claims 1 to 10, characterized in that the resistive heater has a mass between 0.1 g and 0.5 g.
    [12]
    12. Aerosol generating device, according to which
    Petition 870190097361, of 09/30/2019, p. 10/55
    3/3 wants one of claims 1 to 11, characterized in that the battery is a lithium ion battery.
    [13]
    Aerosol generating device according to any one of claims 1 to 12, characterized in that the microcontroller is configured to continuously supply current to the resistive heater of the DC / DC converter for a period of more than 5 seconds.
    [14]
    14. Method for controlling an aerosol generating device (1), the aerosol generating device (1) characterized by the fact that it comprises a resistive heater (4), a battery (2), in which the battery (2) is configured to generate a battery voltage (Vbat), and a control unit (3), the control unit comprising a DC / DC converter (32) arranged to receive the battery voltage (Vbat) as input from the battery and to emit an output voltage (Heater) to the resistive heater (4), the method comprising:
    controlling said DC / DC converter (32) to adjust the output voltage based on a predetermined temperature profile for the resistive heater (4) that varies with time.
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    同族专利:
    公开号 | 公开日
    EP3618648A1|2020-03-11|
    KR20190140455A|2019-12-19|
    RU2019138048A|2021-06-03|
    RU2762188C2|2021-12-16|
    JP2020518236A|2020-06-25|
    WO2018202403A1|2018-11-08|
    RU2019138048A3|2021-09-01|
    PH12019502162A1|2020-06-15|
    EP3618648B1|2021-06-30|
    CN110536617A|2019-12-03|
    US20200046033A1|2020-02-13|
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    法律状态:
    2021-10-19| B350| Update of information on the portal [chapter 15.35 patent gazette]|
    优先权:
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    EP17169337|2017-05-03|
    PCT/EP2018/059477|WO2018202403A1|2017-05-03|2018-04-12|A system and method for temperature control in an electrically heated aerosol-generating device|
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