A method for controlling the heating of a susceptor in an aerosol generating device using a boost converter.

Abstract

A method is described for controlling heating of a susceptor of an aerosol generating device, the susceptor being inductively heated by an oscillator circuit (6) driven by an inverter (5), with an optional boost converter (8) connected between a power supply unit (4) and said inverter (5) configured to boost a voltage from an input voltage provided by the power supply unit to an output voltage transferred to the inverter (5). The method includes a power transfer mode of the aerosol generating device and a temperature discrimination mode of the aerosol generating device, in which the amount of power provided to the inverter is less than the amount of power provided during the power transfer mode. The method includes determining a temperature of the susceptor based on, for example, a determined resonant frequency or a resonant capacitor voltage of the oscillator circuit (6). The power transfer mode may include setting an output voltage transferred from the boost converter (8) to the inverter (5) in dependence on the determined temperature of the susceptor.

Description

[Technical Field]

[0001] This disclosure generally relates to a method for controlling the heating of a susceptor of an aerosol generating device, and an aerosol generating device comprising a controller adapted to implement said method. [Background technology]

[0002] An aerosol generating device generally includes at least one reservoir arranged to store an aerosol generating product. The aerosol generating product is heated without combustion to generate an aerosol for inhalation.

[0003] Aerosol generating products can be heated using various methods. One method involves induction heating. Such aerosol generating devices typically comprise an induction heating system comprising an induction coil, an induction-heatable susceptor, and a power supply unit.

[0004] Electrical energy is supplied to the induction coil by an inverter via a power supply unit or battery. The induction coil then generates an alternating current electromagnetic field. A susceptor couples with the electromagnetic field and generates heat, which is transferred to the aerosol-generating product, for example, by conduction. Finally, the heated aerosol-generating product generates aerosols.

[0005] To optimize the operation of aerosol generating devices, there is a need to pursue the highest possible energy efficiency during induction heating.

[0006] In this context, for example, it is known to use a boost converter for an aerosol generating device. The boost converter is configured to increase the voltage supplied by the power supply unit, that is, to convert a DC voltage to a higher value DC voltage. Chinese Utility Model Registration No. 209732613U discloses such an aerosol generating device. [Overview of the project]

[0007] This disclosure aims to provide an improved method for controlling the inductive heating of a susceptor in an aerosol generating device, and more precisely, for improving energy efficiency using a boost converter.

[0008] Accordingly, the present disclosure relates to a method for controlling the heating of a susceptor of an aerosol generating device, wherein the susceptor is inductively heated by an oscillator circuit driven by an inverter.

[0009] According to a first aspect of the present disclosure, the method includes a power transfer mode for an aerosol generating device and a temperature identification mode for an aerosol generating device in which the amount of power supplied to the inverter is less than the amount of power supplied during the power transfer mode, the method further includes determining the temperature of a susceptor based on measurements taken during the temperature identification mode.

[0010] A boost converter may be connected between the power supply unit and the inverter, and the boost converter is configured to boost the voltage from the input voltage supplied by the power supply unit to the output voltage transmitted to the inverter. The power transfer mode may include the step of setting the output voltage transmitted from the boost converter to the inverter, depending on the determined temperature of the susceptor.

[0011] In this way, efficient power control is possible by regulating the voltage transmitted to the oscillation circuit depending on the temperature of the susceptor, i.e., the aerosol generating product. Determining the temperature of the aerosol generating product and controlling the transmitted voltage therefore enables the generation of the correct amount of aerosol with the appropriate substance with high energy efficiency.

[0012] The output voltage can thus vary depending on the desired heating profile, which itself depends on other parameters such as the properties or type of the aerosol-generating product.

[0013] Furthermore, the boost converter provides smooth power control in induction heating, which is not easy to control.

[0014] This method may include a comparison step performed before the setting step, in which the determined temperature of the susceptor is compared with a target temperature, and the output voltage is set to a value that depends on the determined temperature and the target temperature.

[0015] The output voltage can thus vary depending on the target temperature. For example, it is possible to control the output voltage so that it reaches the target temperature but does not exceed it. Conversely, it is also possible to control the output voltage so that it overshoots the target temperature.

[0016] The aerosol generating device includes a controller configured to control the output voltage of a boost converter to bring the susceptor temperature to a target temperature, the controller being tuned to over-damped, and the output voltage being set to a predefined maximum voltage when the determined susceptor temperature is below a threshold.

[0017] The threshold may be in the range of 60% to 85% of the target temperature.

[0018] The aerosol generating device includes a controller configured to control the output voltage of a boost converter to bring the susceptor temperature to a target temperature, the controller being tuned to underdamped, and the output voltage being set so that the susceptor temperature overshoots the target temperature at the start of susceptor heating.

[0019] The controller may be a PID controller, a model-based controller, and / or a model-predictive controller.

[0020] The output voltage may be substantially set to a predetermined voltage or less, for example, about 8V, when the determined temperature of the susceptor is equal to the target temperature.

[0021] The boost converter can also be an asynchronous boost converter.

[0022] The boost converter may also be a synchronous boost converter.

[0023] The boost converter may include an active switch, which is a MOSFET transistor.

[0024] The boost converter may include a passive switch, which is a MOSFET transistor.

[0025] The boost converter may be configured to boost the voltage from an input voltage in the range of 3 to 4.2V to a desired output voltage. The desired output voltage is sufficient to generate adequate losses within the susceptor for the necessary heating, and in some embodiments, the desired output voltage may be equal to at least 8V. The desired output voltage may depend on the susceptor characteristics, such as resistance, shape, and size.

[0026] If a boost converter is not required, the inverter may be controlled by a controller to adjust induction heating during power transfer mode. For example, the inverter may be periodically enabled and disabled (or periodically controlled to be on and off) with a duty cycle that can be varied to control the heating of the susceptor. Such operation can be called a “global” pulse-width modulation (PWM) control scheme, in which the time (or “pulse width”) the inverter is enabled is variable. The inverter may comprise two transistors. While the inverter is enabled (or on), the transistors can operate with a predetermined duty cycle. While the inverter is disabled (or off), both transistors are turned off.

[0027] The inverter may have two transistors. Preferably, both transistors operate during power transfer mode.

[0028] The oscillator circuit may include a coil circuit and a susceptor circuit. The coil circuit may be, for example, an LLC circuit or an LC circuit, and typically includes at least one inductor or coil and at least one capacitor. In some aspects of this disclosure, an LC circuit may be preferred because it contains fewer components that dissipate the power it contains. In an LLC circuit, an additional filter inductor may increase resistive power loss, which may increase the required battery voltage. This may also result in higher switching losses in the inverter.

[0029] The temperature of the susceptor may be determined based on the determined resonant frequency of the oscillation circuit.

[0030] The above temperature determination step is, - A substep in which only one of the two transistors of the inverter is operated during the temperature identification mode, - A substep to determine the resonant frequency of the oscillation circuit during the temperature identification mode period, - A substep to determine the temperature of the susceptor based on the determined resonance frequency, It may include.

[0031] The temperature of the susceptor may be determined based on an indicated electrical value in the oscillation circuit, for example, the determined maximum value of the voltage across the capacitor in the coil circuit.

[0032] The above temperature determination step is, -During the period of temperature identification mode, for example, the minimum frequency f min and maximum frequency f max While sweeping the frequency within the range between, a substep is performed to determine the maximum value of the indicated electrical value in the oscillator circuit with respect to the frequency range. - A substep to determine the global maximum value from the determined maximum value, - A substep to determine the susceptor temperature based on the global maximum value, It may include.

[0033] The above steps for temperature determination may further include a substep of operating both transistors of the inverter during the temperature identification mode with a reduced duty cycle, for example, about 10% to 15%. More specifically, the duty cycle of the inverter during the temperature identification mode is preferably lower than the duty cycle of the inverter during the power transfer mode. The duty cycle during the temperature identification mode is preferably reduced to a minimum value so as little power as possible is transferred to the susceptor. For example, the temperature rise of the susceptor during a single frequency sweep may be kept below 1°C, which is sufficient to ensure high performance.

[0034] The substep of determining the global maximum value and / or the susceptor temperature based on that global maximum value does not have to be performed during the temperature identification mode. In other words, while the measurements necessary to determine the susceptor temperature are performed during the temperature identification mode, the process for actually determining the susceptor temperature may be performed after the temperature identification mode has ended.

[0035] The power transfer mode and the temperature identification mode may be alternated during the operation of the aerosol generating device.

[0036] The temperature identification mode may be executed at regular time intervals.

[0037] A second aspect of the present disclosure provides a method for controlling the heating of a susceptor of an aerosol generating device, wherein the susceptor is inductively heated by an oscillator circuit driven by an inverter, a boost converter is connected between a power supply unit and the inverter, the boost converter is configured to boost a voltage from an input voltage supplied by the power supply unit to an output voltage transmitted to the inverter, the method comprising a power transfer mode of the aerosol generating device and a temperature identification mode of the aerosol generating device where the amount of power supplied to the inverter is less than the amount of power supplied during the power transfer mode, further comprising the steps of determining the temperature of the susceptor and setting the output voltage transmitted from the boost converter to the inverter during the power transfer mode, depending on the determined temperature of the susceptor.

[0038] Other features of the aerosol generation device and method are as described above.

[0039] According to a third aspect of this disclosure, an aerosol generating device, - Power supply unit, -Induction heating susceptor, - An oscillator circuit arranged to generate a time-varying electromagnetic field for inductive heating of the susceptor, - An inverter configured to drive an oscillation circuit, - A discretionary boost converter connected to the power supply unit on one side and to the inverter on the other side, - An aerosol generating device is provided, comprising a controller adapted to implement a method for controlling the heating of the susceptor as described above. [Brief explanation of the drawing]

[0040] The following explanation will also reveal other special features and advantages of the present invention.

[0041] The attached drawings, provided by non-limiting embodiments, are as follows:

[0042] [Figure 1a] A schematic diagram shows a portion of the aerosol generating device 1 according to one of the two embodiments of this disclosure. [Figure 1b] A schematic diagram shows a portion of the aerosol generating device 1 according to one of the two embodiments of this disclosure. [Figure 2] The electronic circuit of the aerosol generating device is shown in a schematic diagram. [Figure 3] A control loop system according to one embodiment of this disclosure is shown in a schematic diagram. [Figure 4a] Figure 2 shows the oscillator circuit and inverter. [Figure 4b] This represents an oscillator circuit and inverter according to another embodiment of the present disclosure. [Figure 5a] The boost converter circuit in Figure 2 is shown separately. [Figure 5b] This represents a boost converter circuit according to another embodiment of the present disclosure. [Figure 6] This represents the linear dependency between the resonant frequency of the oscillator circuit and the temperature of the susceptor in the aerosol generating device. [Figure 7] A schematic diagram illustrates a method for controlling the induction of heating in the susceptor of an aerosol generating device. [Figure 8] This illustrates an example of temperature control that can be implemented in an aerosol generating device. [Figure 9] This represents the dependency relationship between the voltage of the oscillator circuit and the temperature of the susceptor of the aerosol generating device. [Modes for carrying out the invention]

[0043] Herein, embodiments of the present disclosure will be described with reference to the attached drawings, merely as examples.

[0044] Figures 1a and 1b schematically represent parts of the aerosol generating device 1 according to two different embodiments of the present disclosure. Both Figures 1a and 1b schematically show the mechanical configuration of the aerosol generating device 1, while Figure 2 shows an example of the electronic circuit of the aerosol generating device 1.

[0045] The aerosol generating device 1 comprises a main unit 2 and a cartridge 3.

[0046] The cartridge 3 comprises a first end 30 configured to engage with the main body 2, and a second end 31 positioned as a mouthpiece portion (not shown) having a vapor outlet.

[0047] Cartridge 3 further comprises at least one reservoir 32 arranged for storing the aerosol-generating product 33. Cartridge 3 may be disposable.

[0048] The reservoir 32 is positioned to receive an aerosol-generating product 33 of a corresponding shape. The aerosol-generating product 33 and / or the reservoir may be disposable articles or sticks.

[0049] The term aerosol-generating product is used to specify any material that can vaporize in air to form an aerosol. Vaporization is generally achieved by raising the temperature of the vaporizing material to its boiling point, such as up to 400°C, preferably up to 350°C. The vaporizing material may be, for example, in liquid, solid, or semi-liquid form, and therefore may consist of or comprise liquids, tobacco, gels, or waxes, or any combination thereof.

[0050] The mouthpiece is detachably attached to allow access to the reservoir for the purpose of inserting or removing the aerosol generating product 33.

[0051] The aerosol generating device 1 includes an induction heating system configured to enable heating of the aerosol generating product 33.

[0052] The induction heating system generally includes a power supply unit or battery 4, as well as an inverter 5 and a controller 9 (visible in Figure 3), which are typically housed within the main unit 2.

[0053] The controller 9 is configured to operate other electronic components, including the inverter 5.

[0054] The inverter 5 is configured to convert the DC current from the battery 4 into a high-frequency AC current. The inverter 5 comprises two switches or transistors T0 and T1. Transistors T0 and T1 operate at the same frequency and a predetermined duty cycle. In particular, the duty cycles of the two transistors T0 and T1 of the inverter 5 are equal to 50%. A 50% duty cycle during power transfer mode is generally preferred so that transistors T0 and T1 have a symmetrical load, but it goes without saying that other duty cycles are also possible. It is also possible to operate transistors T0 and T1 with a variable duty cycle, for example, a duty cycle of about 20% to 80%. This may be appropriate when there is no boost converter to adjust the voltage supplied to the inverter and there is no other way to control power transfer.

[0055] The induction heating system further comprises an oscillator circuit 6. The oscillator circuit comprises an inductance provided by a coil 60.

[0056] Coil 60 is a helical induction coil extending from the reservoir 32. The induction coil 60 is energized by the battery 4 and the controller 9. The controller 9 operates at the f frequency at which the oscillation circuit 6 is driven. op It is configured to control.

[0057] Furthermore, the induction heating system includes one or more induction-heatable susceptors 7. A susceptor is an element made of a conductive material and used to heat a non-conductive material or product.

[0058] The inductively heatable susceptor 7 may be in direct or indirect contact with the aerosol generating product 33 such that when the susceptor 7 is inductively heated by the induction coil 60, heat is transferred from the susceptor 7 to the aerosol generating product, heating the aerosol generating product and thereby generating an aerosol.

[0059] In the typical embodiment shown in Figure 1a, the susceptor 7 extends into the reservoir 32 together with the aerosol generating product 33. It is preferable that the susceptor 7 is positioned inside the aerosol generating product 33.

[0060] In another embodiment shown in Figure 1b, the susceptor 7 extends to the outside of the aerosol-generating product 33. Preferably, the susceptor 7 extends along the side wall 320 of the reservoir 32.

[0061] Figure 2 shows a battery circuit 40, an inverter circuit 50, and an oscillator circuit 6 comprising a coil circuit 61 and a susceptor circuit 62. The oscillator circuit 6 is shown separately in Figure 4a. Figure 4b shows another embodiment of a suitable oscillator circuit.

[0062] In the embodiment shown in Figure 4a, the coil circuit 61 is an LCC circuit with an additional inductor. The voltage sensor 63 is adapted to measure the voltage across the capacitor C of the coil circuit 61.

[0063] In the embodiment shown in Figure 4b, the coil circuit 61 is an LC circuit. The voltage sensor 64 is adapted to measure the voltage across one of the capacitors C2 of the coil circuit 61.

[0064] Furthermore, the aerosol generating device 1 also includes a boost converter 8, and an example of its circuit 80 is shown in Figure 2. In particular, Figure 2 includes an example of a boost converter 8 that can be used in the aerosol generating device, which is shown separately in Figure 5a. Figure 5b similarly shows another example of a suitable boost converter 8.

[0065] The boost converter 8 is connected to the battery 4 at one end and to the inverter 5 at the other end. In some embodiments of this disclosure, the boost converter 8 may be omitted, and the inverter 5 is connected directly to the battery 4 or another power source. When the boost converter is absent, the induction heating of the susceptor 7 may be controlled by a controller using a “global” PWM control scheme during the power transfer modes described below. The inverter 5 may operate in the ON state, during which transistors T0 and T1 are switched on and off at predetermined duty cycles. In particular, the duty cycles of the two transistors T0 and T1 of the inverter 5 are equal to 50%. When the inverter 5 operates in the OFF state, the two transistors T0 and T1 are switched off. The overall duty cycle of the “global” PWM control scheme may be controlled to vary the heating of the susceptor 7 during the power transfer modes.

[0066] The boost converter 8 is configured to boost the voltage, that is, to convert a DC voltage to a higher DC voltage. More precisely, the boost converter 8 is configured to boost the input voltage V supplied from the power supply unit 4. in From there, a higher output voltage V is transmitted to inverter 5. out It is configured to boost the voltage.

[0067] The boost converter 8 is a favorable solution for increasing voltage in minimal space.

[0068] A boost converter is a type of switch-mode power supply. In particular, it uses a main switch, such as a transistor, to turn parts of the circuit on and off at a certain speed.

[0069] The boost converter 8 includes an active switch T2 and a passive switch T3.

[0070] The active switch T2, or main switch, is a MOSFET transistor (metal-oxide-semiconductor field-effect transistor) in both of the examples shown.

[0071] In the embodiment shown in Figure 5a, the passive switch T3 or auxiliary switch is a diode. The boost converter is therefore an asynchronous boost converter.

[0072] In the embodiment shown in Figure 5b, the passive switch T3 is a MOSFET transistor. The boost converter 8 is therefore a synchronous boost converter.

[0073] The boost converter 8 further includes an inductor 81 and a capacitor 82.

[0074] The boost converter circuit 80 further includes two sensors, a current sensor 83 and a voltage sensor 84. The current sensor 83 is adapted to measure the output current transmitted by the boost converter 8. The voltage sensor 84 measures the output voltage V transmitted by the boost converter 8. out It is adapted to measure.

[0075] The principle of the boost converter consists of two different states: an on state and an off state. In the on state, the main switch T2 is on, and the inductor 81 is charged. In the off state, the main switch T2 is off, and the energy in the inductor 81 begins to dissipate.

[0076] The boost converter 8 is also characterized by its duty cycle D. The duty cycle D represents the proportion of the rectification period T while the main switch T2 is on. Therefore, D takes values ​​in the range of 0 to 1.

[0077] Average output voltage V out The input voltage V is as shown by the following relationship. in And it is directly related to duty cycle D.

Number

[0078] The boost converter is configured here to boost the voltage from an input voltage V in the range of 3 to 4.2 V in to a higher output voltage V out The output voltage V out is preferably at least equal to 8V.

[0079] The controller 9 is configured here to control the boost converter 8, and in particular to control the output voltage transmitted to the inverter 5.

[0080] Figure 3 shows an example of a control loop system that can be used in the present disclosure. The controller 9 is connected on one side to the inverter 5 and on the other side to the boost converter 8.

[0081] The controller 9 is, for example, a proportional-integral-derivative controller (PID controller).

[0082] For more advanced control and better performance, other topologies or controller types can be used. The controller 9 can be, for example, a model-based controller. Such a controller has the advantage of taking into account the dynamic response of the system that changes with the operating conditions. The model-based controller provides significantly better performance compared to a normal PID controller and shows much lower sensitivity to differences in system characteristics. It allows, for example, a rapid increase or decrease in temperature if necessary.

[0083] In yet another specific embodiment, the controller 9 can be a model predictive controller or a model-based predictive controller. Such a controller can also represent the behavior of a dynamic system and further make predictions regarding the future behavior of the system using a model of the system.

[0084] Hybrid or mixed control methods may also be used. For example, if the aerosol generating device includes a boost converter 8, the boost converter may be controlled by the controller 9 during some operations of the aerosol generating device (e.g., during preheating), while during other operations (e.g., during the vaping phase), the boost converter may be bypassed or disabled, and the induction heating of the susceptor 7 may be controlled by an inductor, for example, using the "global" PWM control scheme described above. During preheating, more power is required, and the boost converter 8 is beneficial in providing a higher output voltage for the inverter 5. A higher voltage means less current is required to achieve the same power, thereby reducing losses. Then, during the vaping phase, less power is required, and the boost converter 8 is not needed. Conduction losses can be reduced by bypassing the boost converter 8 in this way.

[0085] A method for controlling the heating of the susceptor 7 of the aerosol generating device 1 includes the step of first determining the temperature of the susceptor 7.

[0086] The temperature of the susceptor 7 may be determined using any suitable method. For example, the temperature of the susceptor 7 can be determined by first determining the resonant frequency of the oscillation circuit 6.

[0087] In fact, the resonant frequency f of the oscillator circuit r This is influenced by the values ​​of inductance L, resistance R, and capacitance C, and for the LLC circuit shown in Figure 4a, it is given as follows:

number

[0088] Furthermore, the resonant frequency f of the oscillator circuit 6 r This depends on the following: - The precise position of the susceptor 7 relative to the inductance coil 60 of the oscillation circuit 6, and - The resistance of susceptor 7 changes with the temperature of the susceptor.

[0089] Furthermore, resistance variations can also be affected by manufacturing tolerances.

[0090] Therefore, in order to track the change in total resistance, and thus the change in the temperature of the susceptor 7, the resonant frequency f r It can be used.

[0091] More specifically, the resonant frequency f r As shown in Figure 6, it changes linearly with temperature. The function that describes the temperature T of the susceptor 7 as a function of the frequency characteristic F can be written as F(T) = aT + b, where "a" and "b" are constant parameters of the function. Parameter "a" corresponds to the slope value of the frequency curve. Parameter "b" corresponds to the y-intercept.

[0092] The various curves in Figure 6 represent the frequency variation of the oscillator circuit depending on the temperature and position of the susceptor 7. In fact, as explained above, the resonant frequency depends on the position of the susceptor 7 relative to the oscillator circuit. This, therefore, modifies the y-intercept of the frequency curve. This is clearly shown in Figure 6, where the slope "a" is the same for all curves, but the y-intercept differs for each curve.

[0093] In the illustrated embodiment, the y-intercept or b-parameter is the initial resonant frequency f of the resonant circuit. i Corresponds to the initial resonant frequency f. i This refers to the resonant frequency of the oscillation circuit before heating of the susceptor 7. In other words, it corresponds to the resonant frequency when the susceptor 7 is at ambient temperature, i.e., approximately 20°C.

[0094] The illustrated curve shows that it is possible to take into account improper insertion of the susceptor 7 into the aerosol generating device.

[0095] First, the temperature of the susceptor 7 can be determined by determining the resonant capacitor voltage of the oscillator circuit 6. Specifically, the resonant capacitor voltage V of the oscillator circuit at the resonant frequency is... c The inductance L, resistance R, and supply voltage V are all factors. s Influenced by the value of , the following is given for the LC circuit shown in Figure 4b:

number

[0096] Therefore, the resonant capacitor voltage depends on the resistance of the susceptor 7, which changes with the temperature of the susceptor.

[0097] Preferably, the determination step is performed with a low power supply, i.e., a low output voltage V out This is performed by the boost converter 8. The low output voltage V out This means 8V or less. Preferably, the output voltage at a low power supply is approximately equal to 8V. Performing the above determination step at a low power supply allows for a more accurate determination of the susceptor temperature. Moreover, it allows for minimal energy consumption, which is advantageous because energy conversion for heating is not the purpose of this step.

[0098] A method for controlling the heating of the susceptor 7 further includes performing a comparison step, and the determined temperature T of the susceptor 7 d is a predetermined or target temperature T t This is compared to the target temperature. The target temperature refers to a predetermined, pre-set temperature that should be maintained for the purpose of accurate aerosolization of the aerosol-generating product.

[0099] The controller or aerosol generating device 1 controls the susceptor 7 to a predetermined or target temperature T t It goes without saying that it can be configured to store the determined temperature T. d The target temperature T stored tIt may also include a comparator for comparison.

[0100] Next, this method determines the temperature T of the susceptor 7. d The output voltage V transmitted from the boost converter 8 to the inverter 5 depends on this. out This includes the step of setting up.

[0101] Output voltage V of boost converter 8 out The temperature of susceptor 7 reaches the target temperature T. t It can be adjusted to reach and then maintain that state.

[0102] The controller operates in a closed loop, and the determined temperature T of the susceptor 7 d The output voltage V depends on out Adjust.

[0103] For example, the determined temperature T d The target temperature is T t As long as it is less than V, high power supply to inverter 5 will be maintained. High power supply means high output voltage V out This is to mean: High output voltage V out It is higher than 8V. Target temperature T t As the temperature approaches, the power supply can be reduced. Target temperature T t When it reaches this level, the power supply is set to an extremely low level. In other words, the output voltage V out This is set to a low value, preferably 8V or less.

[0104] The heating process and the corresponding output voltage control depend on the design selection and vary depending on parameters such as the properties or type of aerosol-generating product and the desired heating profile.

[0105] Therefore, by repeating the determination step and setting step during the operation of the aerosol generating device, the voltage transmitted to the oscillation circuit 6 can be frequently adjusted. This enables good power control and energy efficiency.

[0106] For example, the determination and setting steps are repeated at certain intervals while the aerosol generating device is operating. The determination and setting steps are repeated at regular intervals.

[0107] In another embodiment, the determination and setting steps can be continuously repeated while the aerosol generating device is operating.

[0108] An example of such a method for controlling the heating of susceptor 7 is shown in Figure 7.

[0109] In this diagram, T refers to the temperature of susceptor 7, and V c V refers to the voltage across the capacitor in the oscillator circuit, T0 and T1 are the two transistors of inverter 5, and the frequency F is that of oscillator circuit 6. out This is the output voltage transmitted by the boost converter 8. All of these parameters are expressed as a function of time.

[0110] First, the initial resonant frequency f of the oscillator circuit. i This is determined. This first step is S in Figure 7. in It is referred to as the initialization step, and is also called the initialization step S. in This is performed when the susceptor 7 is at ambient temperature, i.e., before it is heated.

[0111] initial resonant frequency f i To determine this, low power energy is supplied to the oscillation circuit 6. In particular, only transistor T0 of inverter 5 is operating, and transistor T1 is off. The output voltage V of the boost converter out The voltage is set to a low value, preferably 8V or less. More preferably, the output voltage V out This is equal to 8V.

[0112] Operating frequency f of inverter 5 op Next, the determined initial resonant frequency f i The method for controlling the heating of the susceptor 7 is further set to power transfer mode S. pand temperature identification mode S Ti Includes.

[0113] Power transfer mode S p This is performed while the susceptor 7 is being heated. During this mode, both transistors T0 and T1 of inverter 5 are operating. Output voltage V out This is usually set to a high value. That is, the output voltage V out It is set to a value greater than 8V.

[0114] While the susceptor 7 is heating, the resonant frequency f r It is continuously tracked. In fact, the resonant frequency changes during the operation of the aerosol generating device. Furthermore, the resonant frequency f r Its operation ensures the highest possible energy efficiency.

[0115] Therefore, the controller has a resonant frequency f r Tracking power transfer mode S p Accordingly, the actual operating frequency f during heating op Adjust the operating frequency f. op This is continuously updated to correspond to the resonant frequency of the oscillator circuit.

[0116] Since the resonant frequency is tracked continuously, the temperature can be continuously determined using the curve in Figure 6.

[0117] Using this method to control heating, the temperature of the susceptor 7 is controlled in power transfer mode S p It can be continuously monitored during that period.

[0118] However, a better and more accurate determination of the temperature of susceptor 7 is required. This requires a temperature identification mode S that is performed at certain time intervals. Ti This becomes possible.

[0119] To achieve this, after the power supply is interrupted, a low power energy is supplied to the oscillation circuit. In particular, only transistor T0 operates, and transistor T1 is shut off. Furthermore, the output voltage V out The output voltage V will be lowered. out The voltage can be reduced to a value of 8V or less.

[0120] Next, the resonant frequency is determined. At this time, the temperature of the susceptor 7 can be determined using the curve shown in Figure 6. In practice, the same corresponding curve for the initial resonant frequency is used to determine the temperature of the susceptor. In this disclosure, as explained above, the resonant frequency f r As shown in Figure 6, it changes linearly with temperature. The function that describes the temperature T of the susceptor 7 as a function of the frequency response F can be written as F(T) = aT + b, where "a" and "b" are constant parameters of the function. Parameter "a" corresponds to the slope value of the frequency curve. Parameter "b" corresponds to the y-intercept. The frequency range is approximately 300kHz to approximately 700kHz, but it may also be approximately 100kHz to approximately 700kHz.

[0121] As shown in Figure 6, multiple curves are fitted after the initial resonant frequency is determined. These curves may or may not be shifted, depending on the formula implemented in the controller.

[0122] In another embodiment, these curves can be implemented as a lookup table. The lookup table can be registered in the memory of the aerosol generating device.

[0123] Therefore, at a certain interval, temperature identification mode S Ti This causes the susceptor temperature to reach the target temperature T. t They are precisely identified for the purpose of maintaining them.

[0124] Temperature identification mode S TiReducing the power supplied to the oscillation circuit 6 during this period makes it possible to avoid power transfer to the susceptor 7. In this way, the impact on the temperature of the susceptor 7 is reduced, and a better estimation of the temperature of the aerosol generating product 33 becomes possible.

[0125] Power transfer mode S p and temperature identification mode S Ti This is done alternately.

[0126] Temperature identification mode S Ti This can be repeated at regular intervals for accurate temperature determination.

[0127] In the example shown, power transfer mode S p and temperature identification mode S Ti This is repeated regularly and alternates. However, power transfer mode S p and temperature identification mode S Ti The duration may change while the aerosol generating device is functioning. Depending on the operating factors, temperature identification mode S Ti It would be beneficial to reduce the frequency with which this occurs. For example, during the initial stages of temperature rise, power transfer mode S p Extending the length of may be beneficial, which would enable temperature identification mode S Ti The frequency with which this is performed should decrease.

[0128] Each power transfer mode S p The duration may be, for example, within the range of approximately 30 to 200 ms.

[0129] Each temperature identification mode S Ti The duration can be extremely short, for example, in the range of approximately 2 to 20 ms, in order to obtain stable temperature determination of the susceptor. Each temperature identification mode S TiThe duration of the sweep may depend on other operational factors such as the frequency range required for the sweep and the required resolution. In some cases, the duration of a particular temperature identification mode can be longer than approximately 20 ms, and can be extended to approximately 120 ms for frequency sweeps over a wider frequency range with higher resolution, as described below. The first temperature identification mode may be longer than subsequent temperature identification modes to enable a wider frequency range (e.g., 100 kHz to 700 kHz), while subsequent temperature identification modes use a narrower frequency range (e.g., 350 kHz to 450 kHz). The initial frequency sweep may be performed over a wide frequency range with low resolution to identify an approximate resonant frequency, while subsequent frequency sweeps are performed over a narrower frequency range with higher resolution for a more accurate temperature estimation. The narrower frequency range may target the approximate resonant frequency identified in the initial frequency sweep.

[0130] The temperature fluctuation of the susceptor during each temperature identification mode may be less than approximately 1°C.

[0131] Figure 7 shows the temperature of the susceptor 7 rising over time due to induction heating. The temperature of the susceptor 7 rises to a predetermined or target temperature T t It rises until it reaches that point.

[0132] The temperature of susceptor 7 is controlled here using smooth (slow or overdamping) control. In other words, controller 9 is tuned to overdamping. Overdamping means that the damping ratio is exactly greater than 1. The temperature of susceptor 7 is therefore the target temperature T t The temperature rises gradually until it reaches [value]. By adjusting controller 9 to over-damp, temperature overshoot is prevented or at least reduced.

[0133] The controller therefore sets an appropriate output voltage V to bring the susceptor temperature to the desired temperature. out Apply the solution.

[0134] For example, as long as the determined temperature is below the target temperature, the power supply to the inverter 5 is maintained at a high output voltage V out . As the target temperature T t is approached, the power supply can be reduced. For example, a threshold value is preset, and when the threshold value is exceeded, the temperature is considered to be approaching the target temperature T t . When the target temperature is reached, the power supply is set to be extremely low. That is, the output voltage V out is set to a low value.

[0135] When using over-damping temperature control as shown in FIG. 7, as long as the determined temperature is lower than a predetermined percentage of the target temperature, the output voltage supplied to the inverter 5 can be boosted to a predefined maximum voltage V m . Preferably, the threshold value or the predetermined percentage is between 60% and 85% of the target temperature T t . The threshold value depends on other parameters, especially on the heating rate of the susceptor. For example, when the preheating or the first puff time is extremely fast, for example, set to 2 seconds, the lower limit, that is, about 60% of the target temperature, is preferred. In fact, this avoids overshoot caused by the thermal time difference in temperature determination. The preheating or the first puff shall mean the first period in each use of the aerosol generating device, that is, when the user takes the first puff.

[0136] In the first power transfer mode S p represented in FIG. 7, while the temperature is rising but remains below the target temperature T t , the voltage is boosted until it reaches the voltage value corresponding to the predefined maximum voltage V m .

[0137] As the target temperature T t is approached, the output voltage is reduced. In particular, the output voltage is set to a voltage lower than the predefined maximum voltage V m when the determined temperature of the susceptor is higher than the threshold value or the predetermined percentage of the target temperature. Therefore, in the second power transfer mode S pIn this case, the boost voltage or the output voltage is reduced as the temperature of the susceptor 7 approaches the target temperature T t is reduced.

[0138] When the target temperature is reached, the power supply is set extremely low. Therefore, in the third power transfer mode S of FIG. 7 p the output voltage value is reduced again. Preferably, the output voltage is reduced to 8 V or less.

[0139] Of course, this power control is provided only as an example. In another embodiment, the output voltage V out can be maintained at a predefined maximum voltage V m even when the target temperature is reached, thus causing an overshoot of the temperature of the susceptor. Conversely, in the safety mode, the output voltage V out can always be maintained lower than a predefined maximum voltage V m

[0140] Furthermore, other methods of controlling the temperature, i.e., methods different from over-damping control, can also be used. For example, the temperature of the susceptor 7 can be controlled using fast under-damping control as shown in FIG. 8. In other words, the controller 9 is tuned to be under-damped. Under-damping means that the damping ratio is strictly less than 1. The controller 9 will thus slightly overshoot to reach the target temperature T t more quickly.

[0141] In the embodiment of FIG. 8, the controller 9 is configured to overshoot the temperature of the susceptor 7 for a short time at the start of use of the aerosol generating device, i.e., during preheating. In the example shown, the overshoot is reached in about 0.6 seconds.

[0142] ​The initial puff is improved by tuning controller 9 to underdamping. This high-speed control improves the initial puff while ensuring that several physical limitations are not violated. These physical limitations may include, for example, the absence of tobacco combustion or the degradation of materials in the aerosol generating device or its assembly.

[0143] The temperature of the susceptor 7 may be determined based on the maximum value of the voltage across the capacitor of the coil circuit 61. For example, in the LLC circuit shown in Figure 4a, the voltage across capacitor C determines the temperature for each temperature identification mode S. Ti The voltage may be measured by the voltage sensor 63 during the period. Similarly, for the LC circuit shown in Figure 4b, for example, the voltage across capacitor C2 is measured for each temperature identification mode S Ti The voltage may be measured by the voltage sensor 64 during the period.

[0144] Each temperature identification mode S Ti During this time, resonant peak capacitor voltage detection is performed. The inverter 5 maintains a minimum frequency f while the voltage across the capacitor is being measured. min and maximum frequency f max The frequency is controlled to sweep within a range between [a certain value] and [a certain value]. For example, the minimum frequency f min The frequency may be approximately 350 kHz, and the maximum frequency f max The frequency may be approximately 450 kHz. Frequency sweeps may be performed at a specific resolution, with higher resolution meaning that voltage measurements are taken for more detection frequencies within a given frequency range, and vice versa. Before the peak voltage is detected for each frequency, the voltage measurements from the voltage sensors 63 or 64 may be processed or adjusted, for example, by multiplying the voltage measurements by a gain and / or by removing some DC offset so that only AC signals are considered. The peak capacitor voltage for each frequency is then detected using a high-speed peak detector. For example, V c1 V is the maximum positive capacitor voltage detected at frequency f1. c2V is the maximum positive capacitor voltage detected at frequency f2. c3 This is the maximum positive capacitor voltage detected at frequency f3, and f min and f max The same applies to all detection frequencies between [the specified values]. This peak detection process can be thought of as voltage envelope extraction. And, known peak The peak capacitor voltage V is determined using the detection function. c1 , V c2 , V c3 , , , V cn From this, the global peak capacitor voltage is selected or extracted as the resonant capacitor voltage. The global peak capacitor voltage is selected for a specific temperature identification mode S Ti This is the highest of the peak capacitor voltages detected across all the frequencies swept through.

[0145] Next, the global capacitor peak voltage (or resonant capacitor voltage) can be used to determine the temperature of the susceptor 7. More specifically, the resonant capacitor voltage changes with temperature, as shown in Figure 9. A functional form can be determined that describes the temperature of the susceptor 7 as a function of the capacitor voltage characteristics. Alternatively, a functional form can be determined that describes the temperature of the susceptor 7 as a function of the frequency at which the resonant capacitor voltage is obtained, i.e., the specific frequency at which the highest peak capacitor voltage was measured during the frequency sweep.

[0146] Each temperature identification mode S Ti During this time, transistors T0 and T1 operate at a reduced duty cycle, for example, about 10% to 15%, to minimize heating of the susceptor 7.

[0147] The determined temperature of susceptor 7 is used in the subsequent power transfer mode S. p It can be used to adjust induction heating inside.

[0148] It goes without saying that various modifications and alterations to the currently preferred embodiments described herein will be obvious to those skilled in the art. Such modifications and alterations can be made without departing from the spirit and scope of this disclosure and without diminishing their associated advantages. Accordingly, such changes and alterations are intended to be covered by the appended claims.

[0149] For example, it will be correctly recognized that other functional forms may be used for the dependency between the resonant frequency and the susceptor temperature. For instance, nonlinear functional forms such as appropriately parameterized polynomial functions can be used.

[0150] This disclosure provides a method for controlling induction heating in an aerosol generating device, which thus enables optimization of energy efficiency. Furthermore, the output voltage transmitted to the oscillation circuit can be regulated to obtain a desired temperature profile for the aerosol generating product.

[0151] Unless otherwise stated herein or unless clearly inconsistent with the context, any combination of the features described above, in all possible variations, is encompassed by this disclosure.

[0152] Unless the context clearly indicates otherwise, throughout this specification and the claims, words such as “comprise” and “comprising” should be interpreted comprehensively, that is, “including, but not limited to,” rather than in an exclusive or exhaustive sense. [Explanation of Symbols]

[0153] 1. Aerosol generating device 2 Main unit 3 cartridges 30 First end of cartridge 31 The second end of the cartridge 32 Reservoirs 33. Aerosol-generating products 4 Batteries 40 Battery Circuit 5 Inverter 50 Inverter Circuit T0, T1 Inverter Transistors 6. Oscillator Circuit 60 coils 61 Coil Circuit 62 Susceptor Circuits 63, 64 Voltage Sensor C1, C2 are capacitors in the oscillator circuit. f op Operating frequency f i initial resonant frequency f r resonant frequency 7 Susceptors T d Determined temperature of the susceptor T t Susceptor target temperature 8 Boost Converters 80 Boost Converter Circuit 81 Boost converter inductor 82 Boost converter capacitors 83 Current Sensor 84 Voltage Sensor 9 Controllers T2 Boost Converter Active Switch T3 Boost Converter Passive Switch V in Boost converter input voltage V out Boost converter output voltage S in Initialization Step S p Power transfer mode S Ti Temperature identification mode

Claims

1. A method for controlling the heating of a susceptor (7) of an aerosol generating device (1), wherein the susceptor (7) is inductively heated by an oscillator circuit (6) driven by an inverter (5), and the method controls the power transfer mode (S) of the aerosol generating device (1). ｐ ) and the amount of power supplied to the inverter (5) and the power transmission mode (S ｐ The temperature identification mode (S) of the aerosol generating device (1) is less than the amount of power supplied during ) Ｔｉ The method further includes the temperature identification mode (S Ｔｉ A method comprising the step of determining the temperature of the susceptor (7) based on measurements taken during the process.

2. The determination of the temperature of the susceptor (7) is made by determining the resonant frequency (f) of the oscillation circuit (6). ｒ The method according to claim 1, based on ).

3. The inverter (5) comprises two transistors (T0, T1), and the step of determining the temperature of the susceptor (7) is: A substep in which only one of the two transistors (T0, T1) of the inverter (5) is operated, The aforementioned temperature identification mode (S Ｔｉ ) The resonant frequency (f) of the oscillation circuit (6) ｒ A substep to determine ) and The determined resonant frequency (f ｒ A substep in which the temperature (T) of the susceptor (7) is determined based on the above, The method according to claim 1 or claim 2, including the method described in claim 1 or claim 2.

4. The method according to claim 1, wherein the determination of the temperature of the susceptor (7) is based on the determined maximum value of the indicated electrical value in the oscillation circuit (6).

5. The method according to claim 4, wherein the indicated electrical value is the voltage across the capacitor of the oscillation circuit (6).

6. The step of determining the temperature of the susceptor (7) is: In the temperature identification mode (S Ｔｉ ), a sub-step of determining the maximum value of the indicated electrical value in the oscillation circuit (6) for a certain frequency range, and A substep to determine the global maximum value from the determined maximum value, A substep to determine the temperature of the susceptor (7) based on the global maximum value, The method according to claim 4 or claim 5, including the method described in claim 4 or claim 5.

7. The method according to any one of claims 4 to 6, wherein the inverter (5) comprises two transistors (T0, T1), and the step of determining the temperature of the susceptor (7) further includes a substep of operating both transistors (T0, T1) during the temperature identification mode at a duty cycle reduced from the duty cycle in the power transfer mode (S p).

8. The power transmission mode (S ｐ ) and the temperature identification mode (S Ｔｉ The method according to any one of claims 1 to 7, wherein the operation of the aerosol generating device (1) is performed alternately.

9. The aforementioned temperature identification mode (S Ｔｉ The method according to any one of claims 1 to 8, which is performed at regular time intervals.

10. The aerosol generating device (1) further includes a boost converter (8) connected between the power supply unit (4) and the inverter (5), wherein the boost converter (8) receives an input voltage (V) supplied from the power supply unit (4). ｉｎ The output voltage (V) transmitted from ) to the inverter (5) ｏｕｔ The method is configured to boost the voltage up to the determined temperature (T) of the susceptor (7). ｄ ) in accordance with the power transmission mode (S ｐ ) The output voltage (V) transmitted from the boost converter (8) to the inverter (5) during this time ｏｕｔ The method according to any one of claims 1 to 9, comprising the step of setting ).

11. Furthermore, a comparison step performed before the setting step, wherein the determined temperature (T) of the susceptor (7) ｄ ) is the target temperature (T ｔ The comparison step includes comparing the output voltage (V) with the output voltage (V) ｏｕｔ ) is the determined temperature (T ｄ ) and the target temperature (T ｔ The method according to claim 10, wherein the value is set to a value that depends on ).

12. The aerosol generating device sets the temperature of the susceptor (7) to the target temperature (T ｔ In order to make it the output voltage (V) of the boost converter (8) ｏｕｔ The system includes a controller (9) configured to control the susceptor, the controller (9) being tuned to overdamply, and the output voltage is set to a predetermined maximum voltage (V) when the determined temperature of the susceptor is below a threshold. ｍ The method according to claim 11, wherein the setting is configured as follows.

13. The threshold is the target temperature (T ｔ The method according to claim 12, wherein the value of ) is in the range of 60% to 85%.

14. The aerosol generating device sets the temperature of the susceptor (7) to the target temperature (T ｔ In order to make it the output voltage (V) of the boost converter (8) ｏｕｔ The system includes a controller (9) configured to control the output voltage (V), the controller (9) being tuned to be underdamped, and the output voltage (V ｏｕｔ ) is when the temperature of the susceptor (7) reaches the target temperature (T) at the start of heating of the susceptor (7). ｔ The method according to claim 11, wherein the value is set to overshoot.

15. The method according to any one of claims 12 to 14, wherein the controller (9) is a PID controller, a model-based controller, and / or a model-predictive controller.

16. The determined temperature (T) of the susceptor (7) ｄ ) is the target temperature (T ｔ If the output voltage (V) is equal to the value of ｏｕｔ The method according to any one of claims 11 to 15, wherein the voltage is substantially set to a predetermined voltage or less.

17. The method according to any one of claims 10 to 16, wherein the boost converter (8) is an asynchronous boost converter.

18. The method according to any one of claims 10 to 16, wherein the boost converter is a synchronous boost converter.

19. The method according to any one of claims 10 to 18, wherein the boost converter (8) comprises an active switch (T2), and the active switch (T2) is a MOSFET transistor.

20. The method according to claim 18, wherein the boost converter (8) comprises a passive switch (T3), and the passive switch (T3) is a MOSFET transistor.

21. The boost converter (8) has an input voltage in the range of 3 to 4.2 V (V ｉｎ ) from the desired output voltage (V ｏｕｔ The method according to any one of claims 10 to 20, configured to boost the voltage to ).

22. A method for controlling the heating of a susceptor (7) of an aerosol generating device (1), wherein the susceptor (7) is inductively heated by an oscillating circuit (6) driven by an inverter (5), a boost converter (8) is connected between a power supply unit (4) and the inverter (5), and the boost converter (8) is powered by an input voltage (V) supplied from the power supply unit (4). ｉｎ The output voltage (V) transmitted from ) to the inverter (5) ｏｕｔ The method is configured to boost the voltage to the power transfer mode (S) of the aerosol generating device (1). ｐ ) and the amount of power supplied to the inverter (5) and the power transmission mode (S ｐ The temperature identification mode (S) of the aerosol generating device (1) is less than the amount of power supplied during ) Ｔｉ The method further includes the steps of determining the temperature of the susceptor (7) based on measurements taken during the temperature identification mode (S Ti) and the determined temperature (T Ti) of the susceptor (7) ｄ ) depends on the power transmission mode (S ｐ ) The output voltage (V) transmitted from the boost converter (8) to the inverter (5) during this time ｏｕｔ A method including the steps to set ).

23. The determination of the temperature of the susceptor (7) is made by determining the resonant frequency (f) of the oscillation circuit (6). ｒ The method according to claim 22, based on ).

24. The inverter (5) comprises two transistors (T0, T1), and the step of determining the temperature of the susceptor (7) is: A substep in which only one of the two transistors (T0, T1) of the inverter (5) is operated, The aforementioned temperature identification mode (S Ｔｉ ) The resonant frequency (f) of the oscillation circuit (6) ｒ A substep to determine ) and The determined resonant frequency (f ｒ A substep in which the temperature (T) of the susceptor (7) is determined based on the above, The method according to claim 22 or claim 23, including the method described in claim 22.

25. The method according to claim 22, wherein the determination of the temperature of the susceptor (7) is based on the determined maximum value of the indicated electrical value in the oscillation circuit (6).

26. The method according to claim 25, wherein the indicated electrical value is the voltage across the capacitor of the oscillation circuit (6).

27. The step of determining the temperature of the susceptor (7) is: The aforementioned temperature identification mode (S Ｔｉ ) includes a substep of determining the maximum value of the indicated electrical value in the oscillation circuit (6) for a certain frequency range, A substep to determine the global maximum value from the determined maximum value, A substep to determine the temperature of the susceptor (7) based on the global maximum value, The method according to claim 25 or claim 26, including the method described in claim 25 or claim 26.

28. The method according to any one of claims 25 to 27, wherein the inverter (5) comprises two transistors (T0, T1), and the step of determining the temperature of the susceptor (7) further includes a substep of operating both transistors (T0, T1) during the temperature identification mode at a duty cycle reduced from the duty cycle in the power transfer mode (S p).

29. The power transmission mode (S ｐ ) and the temperature identification mode (S Ｔｉ The method according to any one of claims 22 to 28, wherein the operation of the aerosol generating device (1) is performed alternately.

30. The aforementioned temperature identification mode (S Ｔｉ The method according to any one of claims 22 to 29, wherein the method is performed at regular time intervals.

31. Furthermore, a comparison step performed before the setting step, wherein the determined temperature (T) of the susceptor (7) ｄ ) is the target temperature (T ｔ The comparison step includes comparing the output voltage (V) with the output voltage (V) ｏｕｔ ) is the determined temperature (T ｄ ) and the target temperature (T ｔ The method according to any one of claims 22 to 30, wherein the value is set to a value that depends on the other party.

32. The aerosol generating device sets the temperature of the susceptor (7) to the target temperature (T ｔ In order to make it the output voltage (V) of the boost converter (8) ｏｕｔ The system includes a controller (9) configured to control the susceptor, the controller (9) being tuned to overdamply, and the output voltage being set to a predetermined maximum voltage (V) when the determined temperature of the susceptor is below a threshold. ｍ The method according to claim 31, wherein the setting is configured as follows.

33. The threshold is the target temperature (T ｔ The method according to claim 32, wherein the value of ) is in the range of 60% to 85%.

34. The aerosol generating device sets the temperature of the susceptor (7) to the target temperature (T ｔ In order to make it the output voltage (V) of the boost converter (8) ｏｕｔ The system includes a controller (9) configured to control the output voltage (V), the controller (9) being tuned to be underdamped, and the output voltage (V ｏｕｔ ) is when the temperature of the susceptor (7) reaches the target temperature (T) at the start of heating of the susceptor (7). ｔ The method according to claim 31, wherein the value is set to overshoot.

35. The method according to any one of claims 32 to 34, wherein the controller (9) is a PID controller, a model-based controller, and / or a model-predictive controller.

36. The determined temperature (T) of the susceptor (7) ｄ ) is the target temperature (T ｔ If the output voltage (V) is equal to the value of ｏｕｔ The method according to any one of claims 31 to 35, wherein the voltage is substantially set to a predetermined voltage or less.

37. The method according to any one of claims 22 to 36, wherein the boost converter (8) is an asynchronous boost converter.

38. The method according to any one of claims 22 to 36, wherein the boost converter is a synchronous boost converter.

39. The method according to any one of claims 22 to 38, wherein the boost converter (8) comprises an active switch (T2), and the active switch (T2) is a MOSFET transistor.

40. The method according to claim 38, wherein the boost converter (8) comprises a passive switch (T3), and the passive switch (T3) is a MOSFET transistor.

41. The boost converter (8) has an input voltage in the range of 3 to 4.2 V (V ｉｎ ) from the desired output voltage (V ｏｕｔ The method according to any one of claims 22 to 40, configured to boost the voltage to ).

42. Aerosol generating device (1), Power supply unit (4), Induction heating susceptor (7), An oscillator circuit (6) is arranged to generate a time-varying electromagnetic field for inductively heating the susceptor (7), An inverter (5) configured to drive the oscillation circuit (6), A boost converter (8) is connected to the power supply unit (4) on one side and to the inverter (5) on the other side. A controller (9) adapted to implement a method for controlling the heating of the susceptor (7) according to any one of claims 1 to 41, an aerosol generating device (1) comprising:

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