Method for controlling the heating of the susceptor of an aerosol generator.

Abstract

A method is described for controlling the heating of a susceptor of an aerosol generating device, the susceptor being inductively heated by an oscillating circuit (6) driven at an operating frequency by an inverter (5). The method comprises a power delivery mode of the aerosol generating device and a step of updating the operating frequency, performed during the power delivery mode and including the following sub-steps: - using a controller to identify a resonant frequency of the oscillating circuit (6) during heating of the susceptor; and - using the controller to set the operating frequency to the identified resonant frequency. The updating step is repeated continuously during the power delivery mode of the aerosol generating device.

Description

Technical Field

[0001] The present disclosure generally relates to a method for controlling heating of a susceptor of an aerosol generating device and an aerosol generating device including a controller adapted to execute the method.

Background Art

[0002] An aerosol generating device generally includes at least one storage part arranged to store an aerosol generating material. The aerosol generating material is heated so as not to burn to generate an aerosol for inhalation.

[0003] The aerosol generating material can be heated using various methods. One method is to use induction heating. Such an aerosol generating device therefore includes an induction heating system, which typically includes an induction coil, an inductively heatable susceptor, and a power supply unit.

[0004] Electrical energy is provided to the induction coil by a power supply unit or a battery. The induction coil therefore generates an alternating electromagnetic field. The susceptor couples with the electromagnetic field to generate heat, which is transmitted to the aerosol generating material, for example by conduction. Finally, the heated aerosol generating material generates an aerosol.

[0005] For optimized operation of an aerosol generating device, it is necessary to pursue the highest possible energy efficiency during induction heating.

[0006] International Publication No. WO 2020 / 020970 A1 discloses, for example, a controller of an aerosol generating system for detecting the self-resonant frequency of an induction coil for inductively heating a susceptor of an aerosol generating device. The controller further controls the operation of the aerosol generating device based on the detected self-resonant frequency. In this solution, the highest energy efficiency is not provided when heating the susceptor.

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present disclosure aims to provide an improved method for controlling the induction heating of a susceptor of an aerosol generating device. More precisely, this aims to improve the energy efficiency when heating the susceptor.

Means for Solving the Problems

[0008] The present disclosure therefore relates to a method for controlling the heating of a susceptor of an aerosol generating device, wherein the susceptor is inductively heated by an oscillating circuit driven at an operating frequency by an inverter.

[0009] According to a first aspect of the present disclosure, the method comprises a power delivery mode of the aerosol generating device and a step of updating an operating frequency, which is performed during the power delivery mode and comprises the following sub-steps, namely - a sub-step of using a controller to identify the resonant frequency of the oscillating circuit during heating of the susceptor, and - a sub-step of using a controller to set the operating frequency to the identified resonant frequency including the steps.

[0010] The updating step is continuously repeated during the power delivery mode of the aerosol generating device.

[0011] By continuously updating the operating frequency of the oscillation circuit and setting it to the resonant frequency, it is possible to obtain the most efficient heating of the susceptor.

[0012] The resonant frequency during the updating step can be identified by measuring the phase between the resonant frequency, the current in the induction coil and the voltage of the capacitor of the oscillating circuit, and the resonant frequency corresponds to the frequency obtained when there is a 90° phase shift between the current and the voltage.

[0013] The resonant frequency during the updating step can be identified by minimizing an error function calculated using measured values of electrical indication values within the oscillating circuit.

[0014] The update step may further include a substep that determines the temperature of the susceptor based on the resonant frequency identified during the power delivery mode.

[0015] This feature allows for continuous monitoring of the susceptor temperature during power delivery mode. This monitoring can be used, for example, to control the power supply to the inverter according to a desired heating profile for the susceptor.

[0016] The method may further include a temperature identification mode for the aerosol generator.

[0017] The power delivery mode and temperature identification mode may be alternately repeated during the operation of the aerosol generator.

[0018] The temperature identification mode can be run at regular time intervals.

[0019] The method involves the following substeps, namely - A substep to determine the initial resonant frequency of the oscillator circuit when the susceptor is at ambient temperature, - A substep to set the operating frequency to a specified initial resonant frequency, It may further include an initialization step that includes the following.

[0020] The susceptor temperature can be determined using a predetermined linear function of the resonant frequency of the oscillator circuit and the susceptor temperature, for example, a predetermined linear function where the resonant frequency at ambient temperature corresponds to the initial resonant frequency. The susceptor temperature can also be determined using a predetermined polynomial function of the resonant frequency of the oscillator circuit and the susceptor temperature.

[0021] This provides a simple and efficient method for determining the susceptor temperature based on the resonant frequency identified during the power delivery mode.

[0022] The resonant frequency of the initialization step is, - Sweeping the frequency within a certain range, - Measuring the electrical indicator value within the oscillation circuit, and - Select the resonant frequency within the aforementioned range when the extreme value of the electrical indication is obtained. It can be identified by...

[0023] According to a second aspect of this disclosure, - A susceptor capable of induction heating, - An oscillator circuit arranged to generate a time-varying electromagnetic field for inductive heating of the susceptor, - An inverter configured to drive an oscillator circuit at its operating frequency, - A controller configured to perform the aforementioned method for controlling the heating of the susceptor, An aerosol generator containing [the specified element] is provided.

[0024] The allosol generator may further include a boost converter connected between the power supply unit and the inverter.

[0025] Other characteristics and benefits of this disclosure will also become apparent from the following description. In the attached drawings provided as non-limiting examples: [Brief explanation of the drawing]

[0026] [Figure 1a] A schematic diagram of the aerosol generator 1 according to two embodiments of this disclosure is shown. [Figure 1b] A schematic diagram of the aerosol generator 1 according to two embodiments of this disclosure is shown. [Figure 2a] A schematic diagram of the electronic circuit configuration of the aerosol generator is shown. [Figure 2b] A control loop system according to an embodiment of this disclosure is schematically shown. [Figure 3a] An example of an oscillation circuit used for induction heating in an aerosol generator is shown. [Figure 3b] An example of an oscillation circuit used for induction heating in an aerosol generator is shown. [Figure 3c]An example of an oscillation circuit used for induction heating in an aerosol generator is shown. [Figure 4a] A theoretical example of an oscillation circuit that can be used for induction heating in an aerosol generator is presented. [Figure 4b] The equivalent circuit of the oscillator circuit in Figure 4a is shown. [Figure 4c] Figure 4b shows the vector representation of the current in the oscillator circuit. [Figure 4d] Figure 4b shows the vector representation of the current in the oscillator circuit. [Figure 5] This shows the linear dependence of the resonant frequency of the oscillator circuit of the aerosol generator on the temperature of the susceptor. [Figure 6] A schematic diagram of a method for controlling the induction of heating in the susceptor of an aerosol generator is provided. [Figure 7] This shows an example of temperature control that can be performed in an aerosol generator. [Modes for carrying out the invention]

[0027] Herein, embodiments of the present disclosure will be described as examples only, with reference to the attached drawings.

[0028] Figures 1a and 1b schematically show parts of the aerosol generator 1 according to two embodiments of the present disclosure. Both Figures 1a and 1b schematically show the mechanical configuration of the aerosol generator, while Figure 2a shows an example of the electrical circuit configuration of the aerosol generator.

[0029] An aerosol generator generally includes a main unit 2 and a cartridge 3.

[0030] The cartridge 3 includes 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.

[0031] Cartridge 3 further includes at least one storage section 32 arranged to store the aerosol generating material 33. Cartridge 3 may be disposable.

[0032] The storage unit 32 is positioned to receive an aerosol generating material 33 of a corresponding shape. The aerosol generating material 33 and / or the storage unit 32 may be disposable products or sticks.

[0033] The term aerosol-generating material is used to refer to any material that can be vaporized into air to form an aerosol. Vaporization is generally achieved by raising the temperature to a level higher than the boiling point of the vaporizable material, for example, up to 400°C, preferably up to 350°C. The vaporizable material may be, for example, a liquid, solid, or semi-fluid. The vaporizable material therefore includes or consists of liquids, tobacco, gels, or waxes, or any combination thereof.

[0034] The mouthpiece is detachably attached to allow access to the storage compartment for inserting or removing the aerosol generating material 33.

[0035] The aerosol generator includes an induction heating system configured to enable heating of the aerosol generating material 33.

[0036] The induction heating system includes a power supply unit or battery 4, as well as an inverter 5 and a controller 9 (shown in Figure 2b), which are generally located inside the main unit 2.

[0037] The inverter 5 is configured to convert the DC current from the battery 4 into a high-frequency AC current. The inverter 5 here includes two switches or transistors T0 and T1. Transistors T0 and T1 operate at the same frequency and the same predetermined duty cycle. In particular, the duty cycles of the two transistors T0 and T1 in the inverter 5 are equal to 50%.

[0038] The induction heating system further includes an oscillator circuit 6. The oscillator circuit includes an inductance provided by a coil 60.

[0039] Coil 60 here is a helical induction coil, which extends around the storage unit 32. The induction coil 60 is energized by the power supply unit and the controller.

[0040] The induction heating system also includes one or more induction-heatable susceptors 7. A susceptor is an element made of a conductive material and is used to heat a non-conductive material or product.

[0041] The inductively heatable susceptor 7 can come into direct or indirect contact with the aerosol generating material 33. When the susceptor 7 is inductively heated by the induction coil 60, heat is transferred from the susceptor 7 to the aerosol generating material, heating the material and thereby generating an aerosol.

[0042] In the example shown in Figure 1a, the susceptor 7 extends into the storage section 32 containing the aerosol generating material 33. Preferably, the susceptor is located inside the aerosol generating material 33.

[0043] In another embodiment shown in Figure 1b, the susceptor 7 extends to the outside of the aerosol generating material 33. Preferably, the susceptor 7 extends along the side wall 320 of the storage section 32.

[0044] The controller 9 is configured to operate other electronic components, including the inverter 5.

[0045] The controller 9 is positioned to control the oscillation circuit, for example, the voltage delivered from the battery 4 to the oscillation circuit and the operating frequency f that drives the oscillation circuit. op Control.

[0046] Figure 2a shows the battery circuit configuration 40, the inverter circuit configuration 50, the oscillator circuit 6 including the coil circuit 61, and the susceptor circuit configuration 62.

[0047] The aerosol generator 1 also includes a boost converter 8, the circuit configuration 80 of which is shown in Figure 2a. In some aerosol generators, the boost converter is not required, and the inverter 5 is directly connected to the battery 4. Whether or not a boost converter is required may depend on the characteristics of the susceptor and the oscillation circuit. If the aerosol generator does not include a boost converter, the heating of the susceptor can be controlled by operating the inverter. For example, the inverter can be periodically enabled and disabled on a variable duty cycle to control the heating of the susceptor (i.e., it can be controlled to periodically be on and off). Such operation can be called a “global” pulse width modulation (PWM) control scheme, in which the time the inverter is enabled (i.e., the “pulse width”) is varied. When the inverter is enabled (i.e., on), transistors T0 and T1 of the inverter 5 can be operated on a predetermined duty cycle. During the period when the inverter is disabled (i.e., off), both transistors T0 and T1 are off.

[0048] The boost converter 8 is connected to the battery 4 on one end and to other components connected to the inverter 5 on the other.

[0049] The boost converter 8 is configured to increase the voltage, that is, to transform a certain DC voltage into a higher DC voltage. More precisely, the boost converter 8 takes the input voltage V supplied from the power supply unit 4 and in A higher output voltage V is delivered from to inverter 5. out It is configured to boost the voltage to the following value.

[0050] The boost converter 8 is the best solution for increasing voltage in the smallest possible space.

[0051] The boost converter 8 is a type of switch-mode power supply. Specifically, it uses a main switch, such as a transistor, to turn parts of the circuit on and off at a specific speed.

[0052] The boost converter 8 includes an active switch T2 and a passive switch T3.

[0053] The active switch T2, or main switch, is a MOSFET transistor (metal-oxide-semiconductor field-effect transistor) in this case. The passive switch T3, or auxiliary switch, is a diode in this case. The boost converter is therefore an asynchronous boost converter.

[0054] In other embodiments, the passive switch T3 can be a MOSFET transistor. The boost converter can therefore be a synchronous boost converter.

[0055] The boost converter 8 further includes an inductor 81 and a capacitor 82.

[0056] The controller 9 is configured here to control the boost converter 8, and in particular to control the output voltage delivered to the inverter 5.

[0057] Figure 2b shows an example of a control loop system usable in this disclosure. The controller 9 is connected to the inverter 5 on the one hand and to the boost converter 8 on the other hand.

[0058] Controller 9 is, for example, a proportional-integral-derivative controller (PID controller).

[0059] Other topologies and controller types can be used for more advanced control and better performance. Controller 9 can be, for example, a model-based controller. Such controllers have the advantage of taking into account the dynamic response of the system as it changes with operating conditions. Compared to a conventional PID controller, a model-based controller can achieve significantly higher performance and be far less affected by changes in system characteristics. This allows for, for example, rapid temperature increases and decreases when needed.

[0060] In another specific embodiment, the controller 9 may be a model-predictive controller or a model-based predictive controller. Such a controller may also act on behalf of the dynamic system and, furthermore, use a model of the system to make predictions about the system's future behavior.

[0061] Hybrid or mixed control systems may also be used. For example, if the aerosol generator includes a boost converter 8, the boost converter may be controlled by the controller 9 for some operations of the aerosol generator (e.g., during preheating) and bypassed or disabled for other operations (e.g., during the smoking phase), and the induction heating of the susceptor 7 may be controlled by an inductor, for example, using the aforementioned "global" PWM control scheme. More power is required during preheating, and the boost converter 8 is advantageous in that it provides a higher output voltage for the inverter 5. A higher voltage means that less current is needed to achieve the same power, thereby reducing losses. Subsequently, the required power decreases during the smoking phase, and the operation of the boost converter 8 becomes unnecessary. Therefore, by bypassing the boost converter 8, conduction losses can be reduced.

[0062] Induction heating is generally based on the principles of series, parallel, or series-parallel resonance. The aerosol generator of this invention utilizes the series-parallel resonance principle.

[0063] Furthermore, the resonant circuit commonly used in induction heating is the RLC circuit. However, such circuits suffer significant losses due to the high current flowing through the components at the oscillation frequency. Moreover, the components must be large, resulting in high costs.

[0064] To address these shortcomings, other circuits can be used, such as those shown in Figures 3a, 3b, and 3c. In practice, LLC, LCL, and CLL circuits can be used instead of standard RLC circuits.

[0065] LLC, LCL, and CLL circuits, when operating in parallel resonance, draw minimal current at the resonant frequency and exhibit limited inrush current. This allows for miniaturization of circuit components, reducing costs and enabling the use of smaller components.

[0066] These circuits can be controlled digitally, which makes it possible to implement the measurement of resonant frequencies.

[0067] Figure 4a shows an example of an oscillator circuit for an aerosol generator. This oscillator circuit is used for theoretical explanation before describing the heating control within the aerosol generator. The equivalent circuit for induction heating is replaced by the simpler circuit shown in Figure 4b.

[0068] To determine the frequency of the oscillation circuit, it is necessary to determine the electrical indication value of the oscillation circuit. The electrical indication value is the operating frequency f at which the inverter 5 drives the oscillation circuit. op It can be any numerical value that is a function of . The electrical indicator can be, for example, current, voltage, or impedance.

[0069] In this embodiment, the electrical indicator is voltage. The specific reason for this is that a parallel resonant circuit is implemented. However, as mentioned above, depending on the type of oscillator circuit implemented in the system, voltage or impedance can also be used as the electrical indicator.

[0070] The electrical indication value of the oscillation circuit can be determined using a sensor. In the embodiment shown in Figure 2a, the voltage sensor 10 is positioned to read the voltage value through the capacitor of the oscillation circuit 6.

[0071] Resonant frequency f of the oscillator circuit r This is affected by the values ​​of inductance L, resistance R, and capacitance C, and is shown as follows:

number

[0072] Resonant frequency f of the oscillator circuit r This depends on the following: - The precise position of the susceptor 7 relative to the induction coil 60 of the oscillator circuit 6, and - The resistance of susceptor 7 changes with the temperature of the susceptor. This change in resistance can also be affected by manufacturing tolerances.

[0073] Therefore, the resonant frequency identified during power delivery mode can be used to track changes in the total resistance of the susceptor 7 and, consequently, its temperature.

[0074] More specifically, the resonant frequency f r The temperature changes linearly with temperature, as shown in Figure 5. The functional form describing 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 functional form. The parameter 'a' corresponds to the slope of the frequency curve. The parameter 'b' corresponds to the y-intercept. The functional form can also be a polynomial. However, in practice, the circuit configuration is usually optimized so that the aerosol generator operates in the polynomial linear region, i.e., the locally linear region.

[0075] The various curves in FIG. 5 show the variation of the frequency of the oscillation circuit according to the temperature and position of the susceptor 7. In practice, as described above, the resonance frequency depends on the position of the susceptor 7 with respect to the transmitting circuit. Therefore, this changes the y-intercept of the frequency curve. This is clearly evident from the fact that the slopes in FIG. 5 are the same for all curves and the y-intercepts are different for each curve.

[0076] In the illustrated embodiment, the y-intercept or b parameter corresponds to the initial resonance frequency f of the resonant circuit. r The initial resonance frequency f r shall refer to the resonance frequency of the oscillation circuit before heating the susceptor 7. In other words, this corresponds to the resonance frequency when the susceptor 7 is at the ambient temperature, i.e., about 20°C.

[0077] The curves in the figure thus show that improper insertion of the susceptor 7 into the aerosol generator can be taken into account.

[0078] Next, a method for controlling the heating of the susceptor 7 of the aerosol generator 1 according to an embodiment of the present disclosure will be described while referring to FIG. 6. In this figure, T refers to the temperature of the susceptor 7, V c is the voltage across the capacitor of the oscillation circuit, T0 and T1 are the two transistors of the inverter 5, the frequency F of the oscillation circuit 6, and V out is the output voltage delivered by the boost converter 8. All of these parameters are shown as functions of time, except that the susceptor temperature is shown only for the initialization step S in and the power delivery mode S p .

[0079] First, the initial resonance frequency f of the oscillation circuit i is determined. This first step is shown as S In in FIG. 6 and is also called the initialization step. The initialization step S In is performed when the susceptor 7 is at the ambient temperature, i.e., before heating it.

[0080] The initial resonance frequency fi To identify this, low power energy is supplied to the oscillation circuit. Specifically, only transistor T0 of inverter 5 is operating, and transistor T1 is off. Boost converter output voltage V out This value is set to a low number, preferably a predetermined voltage, for example, about 8V or less.

[0081] By reducing the power delivered to the oscillation circuit 6, power delivery to the susceptor 7 can be avoided.

[0082] Then, the frequency is swept over a certain range, and the electrical indication value within the oscillation circuit is measured. In reality, the initial resonant frequency f i This frequency is selected as the frequency at which the extreme value of the electrical indication is obtained.

[0083] The extreme value refers to the minimum or maximum value, depending on the type of electrical indication specified. The resonant frequency corresponds to the maximum voltage or current value and the minimum impedance value.

[0084] Preferably, the sweep within a certain range is short in duration. For example, the sweep may last a maximum of 50 ms.

[0085] Preferably, frequency transmission is performed multiple times, for example, 4 to 12 times. The initial resonant frequency f is identified. i This is the average value of the resonant frequencies obtained during multiple sweeps.

[0086] Operating frequency f of inverter 5 op Then, the identified initial resonant frequency f i It will be set to this.

[0087] The method for controlling the heating of susceptor 7 is power delivery mode S p This also includes temperature identification mode S. Ti This also includes.

[0088] Power delivery mode S pThis occurs during the heating of the susceptor 7. During this mode, both transistors T0 and T1 of inverter 5 typically operate at a 50% duty cycle. Output voltage V out It is usually set to a high value. That is, the output voltage V out The voltage is set to the desired output voltage. The desired output voltage is sufficient to generate adequate losses for the necessary heating within the susceptor, and in some embodiments, the desired voltage may be higher than 8V. The desired output voltage may depend on the characteristics of the susceptor, such as its resistance, shape, and size.

[0089] During the heating of susceptor 7, the resonant frequency is continuously tracked. In fact, the resonant frequency changes during the operation of the aerosol generator. Furthermore, operating at the resonant frequency ensures that the energy efficiency is as high as possible. Therefore, the controller tracks the resonant frequency and the actual operating frequency f during heating. op Adjust accordingly.

[0090] One way to do this, a direct method, is to measure the phase between the current in the induction coil of the oscillator circuit 6 and the voltage across the capacitor. Resonant frequency f r This corresponds to the frequency obtained when the current and voltage are out of phase by 90°.

[0091] Another method, an indirect method, may involve using electrical measurements within the oscillator circuit, such as current measurements. This method will be explained with reference to Figure 4b, which shows the equivalent circuit of induction heating, and Figures 4c and 4d, which show the vector representations of the current in the equivalent circuit when it is near phase resonance and when it is in phase resonance, respectively.

[0092] As can be seen from Figure 4c, when the state is close to resonance, the following relationship is obtained:

number

[0093] As can be seen from Figure 4d, in the resonant state, the phase angle α is equal to 90°. Therefore, the following relationship is obtained:

number

[0094] The error function is defined to track the resonant state. The error function is defined as the difference between the square of the measured or actual induction coil current and the square of the resonant induction coil current. In other words, the error function can be expressed as follows:

number

number

[0095] The error function can be simplified as follows: ε = -2I r I f cos(α)

[0096] Therefore, in the resonant state, when α = 90°, the error ε is equal to zero.

[0097] When approaching a resonant state, the current can be considered as a sinusoidal peak value. Therefore, the error function can be rewritten as follows:

number

[0098] The induction heating system may further include an estimator that drives the controller 9 and is designed to minimize this error function.

[0099] In power supply mode, the resonant frequency is tracked as long as the susceptor 7 is heated, and the operating frequency f of the inverter 5 is tracked.op The resonant frequency is f r It is set to the operating frequency f. op Therefore, it is continuously updated to correspond to the resonant frequency of the oscillator circuit.

[0100] This configuration ensures that the highest possible energy efficiency can be achieved.

[0101] In one embodiment, the aerosol generator has a specified resonant frequency f r It may include memory configured to store one or more of these values.

[0102] For example, a specific resonant frequency can be saved. Then, when updating the resonant frequency, the generated frequencies can be swept around the saved resonant frequency. For each generated frequency, the electrical indicator value is compared to the value corresponding to the previously saved resonant frequency. If the generated frequency has a higher voltage / current or lower impedance than the one corresponding to the previously saved resonant frequency, it is overwritten.

[0103] The resonant frequency is the power delivery mode S p Because it is continuously tracked, the temperature can be continuously identified using the curve in Figure 5. In practice, the same corresponding curve for the initial resonant frequency is used to identify the susceptor temperature.

[0104] The curve shown in Figure 5 is applied after the initial resonant frequency has been identified. The curve can then be shifted or made independent of the equations implemented in the controller.

[0105] In other embodiments, the curve can be implemented as a lookup table. The lookup table can be stored in the memory of the aerosol generator.

[0106] In one embodiment of the present disclosure, the controller or aerosol generator includes a memory configured to store data including a frequency response and a functional parameter describing temperature as a function of the position of the susceptor 7.

[0107] In reality, the initial resonant frequency f r Once this is known, the resonant frequency at ambient temperature is the initial resonant frequency f i The corresponding curve is selected by utilizing the point that it is equal to the initial resonant frequency f. i Therefore, it represents a reference frequency that allows us to select a curve for determining the temperature of susceptor 7.

[0108] Then, the temperature of the susceptor 7 can be determined by simply reading the corresponding curve based on the value of the resonant frequency. Therefore, the temperature corresponds to the power delivery mode S. p The resonant frequency is updated while the susceptor 7 inside is being heated.

[0109] Using this method to control heating, the temperature of the susceptor 7 will be controlled in power supply mode S. p It can be identified continuously.

[0110] Power supply mode S p and temperature identification mode S Ti The pattern repeats alternately.

[0111] Temperature identification mode S Ti This can be repeated, for example, at regular intervals.

[0112] In this example, power delivery mode S p and temperature identification mode S Ti This is repeated periodically and alternates. However, power delivery mode S p and temperature identification mode S Ti The duration may vary during the operation of the aerosol generator. Temperature identification mode S TI It may be advantageous to reduce how frequently this occurs depending on the operating coefficient. For example, power delivery mode S in the early stages of heating. pExtending the length may be advantageous, thereby enabling temperature identification mode S Ti This will reduce the frequency of performing that action.

[0113] The power supply can be adjusted using any appropriate means. For example, power is adjusted using a boost converter 8 connected between the battery 4 and the inverter 5.

[0114] An example of power supply adjustment is shown in Figure 6. In this figure, the temperature T of the susceptor 7 rises 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 [a certain point].

[0115] It is understood that the controller of the aerosol generator can be configured to store a predetermined or target temperature of the susceptor 7. The same memory used to store data containing functional parameters describing temperature as a function of frequency can be used. The controller or aerosol generator may also include a comparator that compares the specified temperature with the stored target temperature.

[0116] As long as the identified temperature is lower than the target temperature, power supply to the inverter 5 is maintained and the susceptor 7 continues to heat. Target temperature T t As the temperature approaches the target, the power supply can be reduced. Once the target temperature is reached, the power supply will be cut off or set to a very low level.

[0117] More precisely, the first illustrated power delivery mode S p So, the voltage is the maximum voltage value V m The temperature is increased until it reaches the target temperature T t It remains lower. Second power delivery mode S p So, the temperature of susceptor 7 is the target temperature T. t As it approaches the target, the boosted voltage decreases. Then, the third power delivery mode S p Then, the boosted voltage value decreases, preferably approaching a value of approximately 8V.

[0118] In other words, in the example shown in the diagram, controller 9 provides an appropriate output voltage V out The voltage is applied to the inverter to raise the temperature of the susceptor 7 to the desired temperature. Other methods of controlling the heating of the susceptor 7 can also be used, including the aforementioned "global" PWM control method, which does not require the use of a boost converter 8 to increase the voltage.

[0119] The temperature of susceptor 7 is controlled here using smooth (slow, or over-damped) control. In other words, controller 9 is adjusted to be over-damped. Over-damping means that the damping ratio is strictly greater than 1.

[0120] Other methods for controlling temperature, namely those other than over-attenuation control, can also be used. For example, as shown in Figure 7, the temperature of the susceptor 7 can be controlled using fast under-attenuation control. In other words, the controller 9 is adjusted to under-attenuate. Under-attenuation means that the attenuation ratio is strictly less than 1. Therefore, the controller 9 slightly overshoots to reach the target temperature T t This allows for faster temperature rise. The controller 9 can be configured to briefly overshoot the temperature of the susceptor 7 when the aerosol generator is first used, i.e., during preheating.

[0121] Furthermore, temperature identification using the method described above eliminates the need for sensors. Measuring the susceptor temperature using sensors, as done in prior art, has several drawbacks: - When measuring the temperature of the susceptor, an inaccuracy arises between the temperature of the susceptor and that of the heated aerosol generating material. - When measuring the temperature of a susceptor, it is very difficult to ensure that the sensor is in close contact with the susceptor and that there is no residual heat. - Accurate temperature sensors are expensive and require a calibration process as well as additional electronic circuitry to make them precise.

[0122] Furthermore, the method for controlling heating according to this disclosure is non-contact, meaning that physical contact with the susceptor is not required. This makes the method for controlling the heating of the susceptor simpler and more cost-effective.

[0123] Various modifications and improvements to the currently preferred embodiments described herein should be apparent to those skilled in the art. Such modifications and improvements can be made without departing from the spirit and scope of this disclosure and without diminishing the associated advantages. Accordingly, such modifications and improvements are also intended to be included in the claims provided herein.

[0124] For example, it is understood that other functional forms can be used with respect to the dependence of the resonant frequency on the susceptor temperature. For instance, nonlinear functional forms such as appropriately parameterized polynomial functions can also be used.

[0125] This disclosure therefore provides a method for controlling induction heating in an aerosol generator, which can optimize energy efficiency.

[0126] The determination of the resonant frequency of the oscillation circuit and the temperature of the aerosol generating material can be applied to any type of susceptor, taking into account differences in the installation location of the susceptor relative to the inductor. Furthermore, the temperature determination can be adapted to changes in the susceptor or any component of the oscillation circuit, which can be replaced, for example, after a specific period of use or after damage.

[0127] Any conceivable combination of the features described above is included in this disclosure unless otherwise stated herein or is clearly inconsistent with the context.

[0128] Unless the context clearly requires a different interpretation, throughout the description and claims, words such as “comprise” and “comprising” shall be interpreted inclusively, that is, “including but not limited to,” and not exclusively or exhaustively. [Explanation of Symbols]

[0129] 1. Aerosol generator 2 Main unit 3 cartridges 30 First end of cartridge 31 The second end of the cartridge 32 Storage section 320 Side wall of the storage section 33 Aerosol Generating Materials 4 batteries 40 Battery Circuit Configuration 5 Inverter 50 Inverter Circuit Configuration 6. Oscillator Circuit 60 coils 61 Coil Circuit 62 Susceptor Circuits 7 Susceptors Tt Susceptor Target Temperature 8 Boost Converters 80 Boost Converter Circuit Configuration 81 Boost converter inductor 82 Boost converter capacitors 9 Controllers 10 Voltage Sensor T2 Boost Converter Active Switch T3 Boost Converter Passive Switch V in Boost converter input voltage V out Boost converter output voltage f op Operating frequency f i initial resonant frequency f rresonant frequency T0, T1 Inverter Transistors S in Initialization Step S p Power delivery mode S Ti Temperature identification mode

Claims

1. In a method for controlling the heating of a susceptor (7) of an aerosol generator (1), the susceptor (7) is controlled by an inverter (5) to control the operating frequency (f ｏｐ The aerosol generator (1) is inductively heated by an oscillation circuit (6) driven by the aerosol generator (1) in power delivery mode (S ｐ ) and the step of updating the operating frequency, which is performed during the power delivery mode, and the following substeps, namely - Using the controller (9), the resonant frequency (f) of the oscillation circuit (6) is set during heating of the susceptor (7). ｒ A substep to identify ) and - Using the controller (9), the operating frequency (f ｏｐ ) the identified resonant frequency (f ｒ Substeps to set in ) Includes steps that include, The step of updating the power supply mode (S) of the aerosol generator. ｐ A method that is continuously repeated during.

2. The resonant frequency (f) during the updating step. ｒ The resonant frequency (f) is determined by measuring the phase between the current in the induction coil and the voltage across the capacitor of the oscillation circuit (6), and the resonant frequency (f) is determined by measuring the phase between the current in the induction coil and the voltage across the capacitor of the oscillation circuit (6). ｒ The method according to claim 1, wherein ) corresponds to the frequency obtained when there is a 90° phase shift between the current and the voltage.

3. The resonance frequency (f ｒ ) during the updating step is determined by minimizing an error function calculated using a measured value of an electrical indication value in the oscillation circuit (6), the method according to claim 1.

4. The aforementioned update step involves the power delivery mode (S ｐ The identified resonant frequency (f) in ) ｒ The method according to any one of claims 1 to 3, further comprising the substep of determining the temperature (T) of the susceptor (7) based on ).

5. The aforementioned power delivery mode (S ｐ ) During this time, the temperature (T) of the susceptor (7) is the resonant frequency (f) of the oscillation circuit (6). ｒ The method according to claim 4, which is specified using a predetermined linear function between the temperature (T) of the susceptor (7).

6. The aforementioned power delivery mode (S ｐ ) During this time, the temperature (T) of the susceptor (7) is the resonant frequency (f) of the oscillation circuit (6). ｒ The method according to claim 4, which is specified using a predetermined polynomial function between () and the temperature (T) of the susceptor (7).

7. The temperature identification mode of the aerosol generator (1) (S Ｔｉ The method according to any one of claims 1 to 6, further comprising:

8. The aforementioned power delivery mode (S ｐ ) and the temperature identification mode (S Ｔｉ The method according to claim 7, wherein the aerosol generator (1) is operated alternately and repeatedly.

9. The aforementioned temperature identification mode (S Ｔｉ The method according to any one of claims 7 and 8, wherein the procedure is performed at regular time intervals.

10. The following substeps, namely - The initial resonant frequency (f) of the oscillation circuit (6) when the susceptor (7) is at ambient temperature. ｉ A substep to identify ) and - The operating frequency (f ｏｐ ) the identified initial resonant frequency (f ｉ Substeps to be set in ) and Initialization step (S ｉｎ The method according to any one of claims 1 to 9, further comprising:

11. The initialization step (S ｉｎ The initial resonant frequency (fi) at ) is, - Sweeping multiple resonance frequencies (fr) within a certain range, - Measuring the electrical indicator value within the oscillation circuit (6), and - Within the range, the resonant frequency (f) when the extreme value of the electrical indication is obtained. ｒ ) to choose The method according to claim 10, as specified by [the relevant source].

12. In an aerosol generator, - An induction heating susceptor (7), - An oscillator circuit (6) is arranged to generate a time-varying electromagnetic field for inductively heating the susceptor (7), - The oscillation circuit (6) is set to an operating frequency (f ｏｐ An inverter (5) configured to be driven by, - A controller (9) configured to perform the method for controlling the heating of the susceptor (7) according to any one of claims 1 to 11, Aerosol generator containing [aerosol].

13. The aerosol generator according to claim 12, further comprising a boost converter (8) connected between a power supply unit and the inverter (5).

Images