Aerosol generating device and its control method

Abstract

The present application provides an aerosol generating device configured to heat an aerosol generating article to generate an aerosol for inhalation; the device includes: a sensor configured to be penetrated by a changing magnetic field to generate heat for heating the aerosol generating article; a series LC oscillator or a series LCC oscillator having an inductance coil, configured to direct a changing current through the inductance coil to drive the inductance coil to generate a changing magnetic field; and a circuit configured to determine the oscillation frequency of the series LC oscillator or the series LCC oscillator based on the rate of change of the oscillation voltage of the series LC oscillator or the series LCC oscillator. In the above aerosol generating device, the oscillation frequency is determined based on the rate of change of the oscillation voltage.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of heat-not-burn low-temperature smoking devices, and in particular to an aerosol generating device and a control method thereof. Background Art

[0002] Smoking articles (eg, cigarettes, cigars, etc.) burn tobacco during use to produce tobacco smoke. Attempts have been made to replace these tobacco-burning articles by creating products that release compounds without combustion.

[0003] An example of such a product is a heating device that releases compounds by heating rather than burning a material. For example, the material may be tobacco or other non-tobacco products that may or may not contain nicotine. In known devices, tobacco products are heated by a heater that generates heat through electromagnetic induction to generate an aerosol for inhalation. In one prior art embodiment of the above heating device, Patent No. 201580007754.2 proposes an induction heating device for electromagnetic induction heating of special tobacco products; specifically, an induction coil and a capacitor are connected in series or in parallel to form an LC oscillation to form an alternating current, so that the coil generates an alternating magnetic field to induce the receptor to heat and heat the tobacco product. The above known heating devices usually use an operational amplifier to synchronously output the oscillation voltage of the LC oscillation or use a zero-crossing comparator to detect the time when the oscillation voltage crosses zero, and then the control chip samples the above result to calculate the frequency of the LC oscillation. In practice, since the frequency of the LC oscillation is very high, approximately 200 to 400 kHz, the control chip must be able to sample the instantaneous output results of the above comparators and amplifiers. Therefore, the sampling speed of the control chip must be around tens of MHz to avoid missing the result signal of the instantaneous output of the comparator or amplifier. Therefore, it is not advisable to track the frequency of the LC oscillation in this way. Summary of the Invention

[0004] An embodiment of the present application provides an aerosol generating device configured to heat an aerosol generating article to generate an aerosol for inhalation; comprising:

[0005] a susceptor configured to be penetrated by the changing magnetic field and generate heat to heat the aerosol-generating article;

[0006] A series LC oscillator or a series LCC oscillator having an inductor coil, configured to direct a varying current to flow through the inductor coil to drive the inductor coil to generate a varying magnetic field;

[0007] The circuit is configured to determine the oscillation frequency of the series LC oscillator or series LCC oscillator according to the rate of change of the oscillation voltage of the series LC oscillator or series LCC oscillator. The above aerosol generating device determines the oscillation frequency according to the rate of change of the oscillation voltage.

[0008] In a preferred embodiment, the circuit includes:

[0009] An active differential unit configured to detect a change rate of an oscillation voltage of the series LC oscillator or the series LCC oscillator and output a high-level signal when the change rate of the oscillation voltage is greater than a preset threshold;

[0010] A controller configured to determine an oscillation frequency of the series LC oscillator or the series LCC oscillator according to an interval time of the high-level signal.

[0011] In a preferred embodiment, the active differential unit includes: an active differential module and a comparator; wherein,

[0012] The active differential module is configured to detect a change rate of an oscillation voltage of the series LC oscillator or the series LCC oscillator;

[0013] The comparator is configured to perform a comparison operation on the change rate of the oscillation voltage and a preset threshold, and output a high-level signal to the controller when the change rate of the oscillation voltage is greater than the preset threshold.

[0014] In a preferred embodiment, the active differential module includes: a first capacitor, a first resistor, a second capacitor, a second resistor, and an operational amplifier; wherein,

[0015] A first end of the first capacitor is connected to the series LC oscillator or the series LCC oscillator, and a second end thereof is connected to a first end of the first resistor;

[0016] A first input terminal of the operational amplifier is connected to a second end of the first resistor, and an output terminal thereof is connected to the comparator;

[0017] A first end of the second capacitor is connected to the second end of the first resistor, and a second end thereof is connected to the output terminal of the operational amplifier;

[0018] A first end of the second resistor is connected to the second end of the first resistor, and a second end thereof is connected to the output terminal of the operational amplifier.

[0019] In a preferred embodiment, the active differential unit further includes:

[0020] An access module including: a first diode, a third resistor, and a fourth resistor; wherein,

[0021] A first end of the first diode is connected to the series LC oscillator or the series LCC oscillator, and a second end thereof is connected to a first end of the third resistor, and is configured to only allow current to flow from the series LC oscillator or the series LCC oscillator to the third resistor;

[0022] The second end of the third resistor is connected to the active differential module;

[0023] The first end of the fourth resistor is connected to the second end of the third resistor, and the second end is grounded.

[0024] In a preferred embodiment, the access module further includes: a zener diode; the first end of the zener diode is connected to the second end of the third resistor, and the second end is connected to the second end of the fourth resistor.

[0025] In a preferred embodiment, the preset threshold is the output value of the active differential module when the change rate of the oscillation voltage is 0.

[0026] In a preferred embodiment, the controller is configured to adjust the oscillation frequency of the series LC oscillator or the series LCC oscillator so that the oscillation frequency of the series LC oscillator or the series LCC oscillator is the same as or substantially close to a preset frequency.

[0027] Another embodiment of the present application further provides a control method for an aerosol generating device, the aerosol generating device including:

[0028] A receptor configured to be penetrated by a changing magnetic field and generate heat to heat an aerosol generating article;

[0029] A series LC oscillator or a series LCC oscillator having an inductance coil, configured to guide a changing current through the inductance coil to drive the inductance coil to generate a changing magnetic field;

[0030] The method includes:

[0031] Detecting the change rate of the oscillation voltage of the LCC oscillator or the series LC oscillator;

[0032] Generating a high-level signal when the change rate of the oscillation voltage is higher than a preset value;

[0033] Determining the oscillation frequency of the LCC oscillator or the series LC oscillator according to the interval time of the high-level signal.

[0034] In a preferred embodiment, it further includes:

[0035] Adjusting the oscillation frequency of the series LC oscillator or the series LCC oscillator so that the oscillation frequency of the series LC oscillator or the series LCC oscillator is the same as or substantially close to a preset frequency. Description of the Drawings

[0036] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings represent similar elements. Unless otherwise stated, the drawings in the figures do not constitute a scale limitation.

[0037] Figure 1 is a schematic structural diagram of an aerosol generating device provided by an embodiment of the present application;

[0038] Figure 2 is Figure 1 a structural block diagram of an embodiment of the circuit in

[0039] Figure 3 is Figure 2 a schematic diagram of the basic components of an embodiment of the circuit in

[0040] Figure 4 is Figure 3 a schematic diagram of the forward current in one stage of the LCC oscillator in

[0041] Figure 5 is Figure 3 a schematic diagram of the reverse current in one stage of the LCC oscillator in

[0042] Figure 6 is Figure 3 a schematic diagram of the resonant current of the series-connected LCC oscillator in

[0043] Figure 7 is Figure 3 a schematic diagram of the changes in the resonant current and resonant voltage during the test of the series-connected LCC oscillator in

[0044] Figure 8 is a schematic diagram of the signal changes in three stages of the active differential unit;

[0045] Figure 9 is a schematic diagram of a control method for an aerosol generating device proposed in an embodiment. Detailed implementation manners

[0046] To facilitate the understanding of the present application, the present application will be described in more detail below in conjunction with the drawings and specific implementation manners.

[0047] An embodiment of the present application proposes an aerosol generating device, the structure of which can be seen in Figure 1 as shown, including:

[0048] a chamber, in which the aerosol generating article A is removably received;

[0049] an inductive coil L, used to generate a changing magnetic field under an alternating current;

[0050] The sensor 30, at least a part of which extends into the chamber and is configured to be inductively coupled with the inductive coil L, generates heat when penetrated by a changing magnetic field, and then heats the aerosol generating article A such as a cigarette, so that at least one component of the aerosol generating article A volatilizes to form an aerosol for inhalation.

[0051] The battery cell 10 is a rechargeable DC battery cell that can output DC current.

[0052] The circuit 20 is electrically connected to the rechargeable battery cell 10 appropriately, and is used to convert the DC current output by the battery cell 10 into an alternating current with a suitable frequency and then supply it to the inductive coil L.

[0053] According to the settings during product use, the inductive coil L may include a cylindrical inductor coil wound in a spiral shape, as Figure 1 shown. The cylindrical inductive coil L wound in a spiral shape may have a radius r in the range of about 5 mm to about 10 mm, and in particular, the radius r may be about 7 mm. The length of the cylindrical inductive coil L wound in a spiral shape may be in the range of about 8 mm to about 14 mm, and the number of turns of the inductive coil L may be in the range of about 8 turns to 15 turns. Accordingly, the internal volume may be in the range of about 0.15 cm 3 to about 1.10 cm 3 range.

[0054] In a more preferred embodiment, the frequency of the alternating current supplied by the circuit 20 to the inductive coil L is between 80 KHz and 400 KHz; more specifically, the frequency may be in the range of about 200 KHz to 300 KHz.

[0055] In a preferred embodiment, the DC supply voltage provided by the battery cell 10 is in the range of about 2.5 V to about 9.0 V, and the amperage of the DC current that the battery cell 10 can provide is in the range of about 2.5 A to about 20 A.

[0056] In a preferred embodiment, the susceptor 30 is generally in the shape of a pin or a blade, which is advantageous for insertion into the aerosol-generating article A; at the same time, the susceptor 30 may have a length of about 12 mm, a width of about 4 mm and a thickness of about 0.5 mm, and may be made of grade 430 stainless steel (SS430). As an alternative embodiment, the susceptor 30 may have a length of about 12 mm, a width of about 5 mm and a thickness of about 0.5 mm, and may be made of grade 430 stainless steel (SS430). In other variant embodiments, the susceptor 30 may also be configured in a cylindrical or tubular shape; during use, its internal space forms a chamber for receiving the aerosol-generating article A, and aerosol for inhalation is generated by heating the outer periphery of the aerosol-generating article A. These susceptors may also be made of grade 420 stainless steel (SS420) and alloy materials containing iron / nickel (such as permalloy).

[0057] In Figure 1 the illustrated embodiment, the aerosol-generating device further includes a bracket 40 for arranging the inductance coil L and the susceptor 30, and the material of the bracket 40 may include high-temperature resistant non-metallic materials such as PEEK or ceramics. In practice, the inductance coil L is fixed by being wound around the outer wall of the bracket 40. At the same time, according to Figure 1 the illustration, the hollow tubular shape of the bracket 40, and a partial space of its tubular hollow forms the above-mentioned chamber for receiving the aerosol-generating article A.

[0058] In an alternative embodiment, the susceptor 30 is prepared from the above-mentioned sensitive material, or a sensing material coating is formed on the outer surface of a heat-resistant matrix material such as ceramics by electroplating, deposition, etc.

[0059] The structure and basic components of the above circuit 20 in a preferred embodiment can be seen in Figures 2 to 3 the illustration, including:

[0060] An LCC oscillator 24, which is composed of the above inductance coil L, a first capacitor C1 and a second capacitor C2; the LCC oscillator 24 is used to form an alternating current flowing through the inductance coil L during oscillation, so that the inductance coil L generates an alternating magnetic field to induce the susceptor 30 to heat up;

[0061] A half-bridge 23, that is, a half-bridge circuit composed of transistor switches; including a switching transistor Q1 and a switching transistor Q2, which are used to make the LCC oscillator 24 oscillate by alternately turning on and off;

[0062] A half-bridge driver 22, which is used to control the switching transistors Q1 and Q2 of the half-bridge 23 to alternately conduct and disconnect according to the control signal of the MCU controller 21.

[0063] For the complete connection method and detailed oscillation process of the LCC oscillator 24 in the above embodiments, refer to Figure 3 as shown; specifically,

[0064] In terms of connection, the first end of the first capacitor C1 is connected to the positive electrode of the battery cell 10, and the second end is connected to the first end of the second capacitor C2; the second end of the second capacitor C2 is grounded through the resistor R1;

[0065] The first end of the switching transistor Q1 of the half-bridge 23 is connected to the positive electrode of the battery cell 10, and the second end is connected to the first end of the switching transistor Q2. The second end of the switching transistor Q2 is grounded through the resistor R1; of course, the controlled ends of the switching transistor Q1 and the switching transistor Q2 are both connected to the half-bridge driver 22, and then conduct and disconnect under the drive of the half-bridge driver 22;

[0066] The first end of the inductor coil L is connected to the second end of the switching transistor Q1, and the second end is connected to the second end of the first capacitor C1. At the same time, in terms of the hardware selection of the LCC oscillator 24, the maximum voltage values of the first capacitor C1 and the second capacitor C2 are much larger than the output voltage value of the battery cell 10. For example, in a general implementation, the output voltage of the battery cell 10 used is basically about 4V, while the maximum voltages of the first capacitor C1 and the second capacitor C2 used are 30 - 80V.

[0067] In the LCC oscillator 24 with the above structure, when the switching states of the switching transistor Q1 and the switching transistor Q2 change, the connection states of the first capacitor C1 and the second capacitor C2 with the inductor coil L change. Specifically, in Figure 3 when the switching transistor Q1 conducts and the switching transistor Q2 disconnects, the first capacitor C1 and the inductor coil L together form a closed series LC circuit, and the second capacitor C2 and the inductor coil L form a series LC circuit with both ends connected to the positive and negative electrodes of the battery cell 10 respectively; when the switching transistor Q1 disconnects and the switching transistor Q2 conducts, the formed circuit is opposite to the above state. The first capacitor C1 and the inductor coil L form a series LC circuit with both ends connected to the positive and negative electrodes of the battery cell 10 respectively, and the second capacitor C2 and the inductor coil L together form a closed series LC circuit. In their respective different states, the first capacitor C1 and the second capacitor C2 can both form their respective LC circuits with the inductor coil L. However, in the oscillation process of their respective LC circuits, the direction and period of the current flowing through the inductor coil L are the same, and thus they jointly form an alternating current flowing through the inductor coil L.

[0068] Specifically, the control steps for the oscillation process of the LCC oscillator 24 with the above structure are different from those of conventional series or parallel LC oscillators. Further, in a preferred implementation of the present application, the complete oscillation process of the LCC oscillator 24 is described by the switching actions of the switching transistor Q1 and the switching transistor Q2; including:

[0069] S10. Turn on the switching transistor Q1 and keep the switching transistor Q2 off. In this state, the LCC oscillator 24 completes the following two processes. Specifically,

[0070] S11: As Figure 4 shown, when the switching transistor Q1 is turned on and the switching transistor Q2 is off, the battery cell 10 charges the second capacitor C2 through the current i1, and at the same time, the first capacitor C1 discharges through the current i2. During this process, a current flowing through the inductor coil L from left to right as shown in Figure 4 can be recorded as a current in the positive direction. In this stage S11, the first capacitor C1 starts to discharge when the switching transistor Q1 is turned on until the voltage difference across both ends is 0 and the discharge is completed, and the voltage across the second capacitor C2 increases to be equal to the output voltage of the battery cell 10 and the charging stops. At this time, the current in the inductor coil L reaches the maximum resonance peak.

[0071] S12: After stage S11 is completed, keep the switching transistor Q1 on and the switching transistor Q2 off. The inductor coil L discharges to charge the first capacitor C1 in the same direction as the current i2 in Figure 1 , so that the current flowing through the inductor coil L in the positive direction gradually decreases until the inductor coil L discharges to a current of 0 and ends. In this stage, since the first capacitor C1 is discharged in stage S11, there is basically no impedance in the loop formed by the inductor coil L and the first capacitor C1 through the switching transistor Q1. Therefore, in this stage S12, the inductor coil L mainly discharges to charge the first capacitor C1, and the current flowing through the inductor coil L during the discharge process is the same as the current i2 in stage S11. The second capacitor C2 has been basically charged to the same voltage as the output voltage of the battery cell 10 in stage S11. In this stage S12, the inductor coil L compensates the second capacitor C2 very little, but it can be basically ignored.

[0072] During the complete processes of stage S11 and stage S12, the total current flowing through the inductor coil L increases from 0 in the positive direction to the maximum, and then gradually decreases to 0 due to the discharge of the inductor coil L, and the direction of the current flowing through the inductor coil L is always the positive direction from left to right.

[0073] S20. After step S10 is completed, turn off the switching transistor Q1 and turn on the switching transistor Q2 to complete the processes of the following two stages. Specifically,

[0074] S21: Starting from when the switching transistor Q2 is turned on, a loop of the current i3 and the current i4 as shown in Figure 5 is generated inside the LCC oscillator 24. According to Figure 5In the current path shown in the figure, the current i3 forms a loop from the positive electrode of the battery cell 10, passing through the first capacitor C1, the inductor coil L, and the switching transistor Q2 in sequence, and then returning to the negative electrode of the battery cell 10 through the ground; at the same time, the current i4 forms a loop from the positive terminal of the second capacitor C2 along the counterclockwise direction shown in the figure, passing through the inductor coil L and the switching transistor Q2 in sequence, and then returning to the negative terminal of the second capacitor C2. During this process, a current flowing through the inductor coil L from right to left as shown in Figure 5 is formed, which is opposite to the current direction in Figure 4 , so it can be recorded as a current in the negative direction.

[0075] In stage S21, the charging of the first capacitor C1 and the discharging of the second capacitor C2 are both included; when the voltage of the first capacitor C1 increases to be equal to the output voltage of the battery cell 10 and the voltage difference across the second capacitor C2 is 0, the current in the inductor coil L reaches the maximum resonance peak.

[0076] S22: After stage S21 is completed, the switching transistor Q2 continues to be turned on. The inductor coil L will charge the second capacitor C2 in the reverse direction, so that the current flowing through the inductor coil L in the negative direction gradually decreases until the inductor coil L discharges to a current of 0 and ends.

[0077] During the entire processes of stage S21 and stage S22 in step S20, the total current flowing through the inductor coil L also increases from 0 in the reverse direction to the maximum, and then gradually decreases to 0 due to the discharge of the inductor coil L.

[0078] Therefore, during the oscillation of the above LCC oscillator 24, the change in the current flowing through the inductor coil L can be seen in Figure 6 shown. A complete current cycle includes four parts corresponding to the above stages S11 / S12 / S21 / S22 in Figure 6 . By alternately switching the on / off states of the switching transistor Q1 and the switching transistor Q2 in steps S10 and S20 in a cyclic manner, the oscillation processes of the above stages S11 / S12 / S21 / S22 can be generated cyclically within the LCC oscillator 24, forming an alternating current flowing through the inductor coil L.

[0079] Therefore, based on the above control process, it can be seen that the LCC oscillator 24 of the present application generates inversion in the ZCS (zero current switching) inverter topology, which is different from the ZVS (zero voltage switching) inverter topology of the existing LC oscillator; and the switching transistor Q1 and the switching transistor Q2 are configured to perform on / off switching when the current flowing through the inductor coil L is 0.

[0080] In Figure 3In the preferred embodiment shown, the number of the first capacitor C1 and the second capacitor is both 1. In other alternative embodiments, the first capacitor C1 or the second capacitor C2 may each include 2 or 3 capacitors with relatively smaller capacitance values connected in parallel. For example, when the first capacitor C1 is replaced with multiple smaller capacitors to replace the originally required relatively large capacitor, their capacitances are equal or approximately equal; then, with the change of the oscillation frequency of the LCC oscillator 24, the ESR (equivalent resistance value) that can be significantly reduced and changed compared to when there is only a single capacitor can be presented accordingly. Specifically, when the frequency is low, the ESR shows a relatively high performance, and when the frequency is high, the ESR shows a relatively low performance, which may be beneficial for preventing spike pulses. And when multiple smaller capacitors are used to replace the originally required relatively large capacitor, it is beneficial to reduce the resonance frequency of the LCC oscillator 24.

[0081] Using the above circuit 20 of the LCC oscillator 24, inversion is formed by the ZCS technology during implementation, and the resonance frequency is basically halved compared to the current LC series / parallel oscillation with a single capacitor. Usually, when the LC series / parallel oscillation frequency is about 380 Hz, the oscillation frequency of the above LCC oscillator 24 is about 190 KHz, which is beneficial for both synchronous detection and the control of the MCU controller 21.

[0082] And during the above oscillation process, the changes in the resonance voltage and current of the LCC oscillator 24 obtained by detection are shown in Figure 7 the figure; the resonance voltage is approximately ahead of the resonance current by 1 / 4 of a cycle, and the overall LCC oscillator 24 is weakly inductive. "Capacitive" and "inductive" are electrical terms related to the mixed circuit of electronic devices (such as an LC oscillator or the above LCC oscillator 24); when the capacitive reactance of the mixed circuit is larger than the inductive reactance, the circuit is "capacitive", and if the inductive reactance is larger than the capacitive reactance, the circuit is inductive. The "weakly inductive" state means that the inductive reactance and the capacitive reactance are basically close and the inductive reactance is slightly larger than rather than much larger than the capacitive reactance.

[0083] Further referring to Figure 3 the embodiment shown, the half-bridge driver 22 uses a commonly used switch tube driver of the FD2204 model, which is controlled by the MCU controller 21 in a PWM manner. According to the pulse width of the PWM, high level / low level is alternately sent from the 3rd and 10th I / O ports to drive the conduction time of the switch tube Q1 and the switch tube Q2, so as to control the oscillation of the LCC oscillator 24.

[0084] From the above detailed control steps, the process of LCC inversion is symmetric, so the MCU controller 21 can drive the half-bridge 23 to switch in this way by sending a PWM control signal with a 50% duty cycle to the half-bridge driver 22.

[0085] Further referring to Figure 2, in order to accurately detect the oscillation frequency of the above LCC oscillator 24, the circuit 20 further includes: an active differentiation unit 25; during the detection by the active differentiation unit 25, the following steps are included:

[0086] Based on the characteristic that the oscillation voltage gradually reaches the maximum while the current becomes 0, first detect the change rate / derivative of the oscillation voltage of the LCC oscillator 24;

[0087] And when the change rate or derivative of the voltage is compared with a preset threshold, when it is greater than the preset threshold, a pulsed interrupt signal is output to the MCU controller 21;

[0088] The MCU controller 21 can obtain the oscillation frequency of the LCC oscillator 24 according to the time interval of the received interrupt signal.

[0089] Specifically, the implementation of the above process is realized by Figure 3 the three sub-modules of the active differentiation unit 25 shown, specifically including:

[0090] A signal access module, which consists of a diode D1, resistors R2 and R3, and a voltage regulator diode Z; the diode D1 allows the voltage of the positive half-waveform of the LCC oscillator 24 to be accessed while filtering out the voltage of the negative half-waveform, and then the resistors R2 and R3 are used for voltage division; Z is a voltage regulator diode to prevent the input voltage from being too large and protect the subsequent circuit;

[0091] An active differentiation module, in Figure 3 a conventional active differentiation circuit with standard basic devices is adopted, which consists of an operational amplifier U1, a capacitor C3, resistors R4, R5, R6, and a capacitor C4 and a resistor R6; among them, the operational amplifier U1, the capacitor C3, and the resistor R4 are the basic necessary components for forming the active differentiation module; the ratio of the resistors R4 and R7 is 1 to avoid higher spikes in the output, make the circuit have the flattest amplitude-frequency response and reduce the Q value; the capacitor C4 is for voltage stabilization purposes to avoid self-oscillation of the operational amplifier;

[0092] The voltage signal Vout output by the active differentiation module during operation is:

[0093] In the formula, PP_LCC is the resonant voltage of the LCC oscillator 24; according to the principle of this calculation formula, the output result is the derivative of the resonant voltage of the LCC oscillator 24 with respect to time t and the comprehensive operation result of the relevant device parameters in the active differentiation, and the parameters of the relevant devices are known and given, so the output result can be equivalent to the derivative of the voltage with respect to time, that is, the change rate of the voltage.

[0094] A comparison output module, in Figure 3 mainly the comparator U2; when the Vout output by the active differentiation module is higher than the preset threshold, a high level is output.

[0095] For the convenience of understanding by technicians, Figure 8 A schematic diagram of the signal changes in three stages of the active differential unit 25 detected in an embodiment is shown; wherein,

[0096] Signal 1 is a graph of the voltage signal at the point between resistor R2 and resistor R3 of the signal access module;

[0097] Signal 2 is a graph of the voltage signal Vout output by the operational amplifier U1 of the active differential module;

[0098] Signal 3 is a graph of the pulsed square wave output by the comparator U2.

[0099] It should be noted that according to the above calculation formula of the output voltage signal Vout, Figure 8 Signal 2 is negatively correlated with Signal 1; that is, when Signal 1 is rising, Signal 2 outputs a negative value until Signal 2 is 0 when Signal 1 reaches the peak; when Signal 1 starts to decline from the peak, Signal 2 outputs a positive value; however, since the active differential module cannot output a negative signal, a reference value is added to the result in the operation so that Signal 2 always outputs a positive value. And the comparator U2 uses this reference value as the comparison basis. When Signal 2 starts to be higher than this reference value and continues to increase, it means that Signal 1 is in the process of declining from the peak; and then a low level is output after the decline ends. According to the above description, the formula will use the signal value output when Signal 1 reaches the peak, that is, when the voltage change rate is 0, as the reference value of the reference input terminal of the comparator U2, that is, R6*2.5 / (R5+R6).

[0100] Then according to the above, in the implementation, the MCU controller 21 does not need to actively sample the oscillation frequency of the LCC oscillator 24 at a high frequency; only the pulsed square wave of Signal 3 needs to be sent to the MCU controller 21 as an interrupt signal. After receiving this signal, the MCU controller 21 calculates the interval time (i.e., the period) between adjacent square waves to calculate and obtain the frequency. Among them, the electrical term "interrupt signal" is a control method of chips or microcontrollers and the like. Specifically, when the CPU or the receiving process receives this "interrupt signal", it temporarily stops other processes or tasks, and after completing the function or process corresponding to the "interrupt signal" at an appropriate time, it returns to the original process or task.

[0101] In the above manner, the active differential module 25 detects the voltage change rate or derivative of the LCC oscillator 24, and then generates a square wave with the same frequency through comparison and operation, and sends this square wave to the MCU controller 21 as an interrupt signal. After receiving this signal, the MCU controller 21 calculates the interval time (i.e., the period) between adjacent square waves to calculate and obtain the frequency.

[0102] In yet another variant implementation, the above LCC oscillator 24 can be replaced or equivalently an identical symmetric-resonant series LC oscillator can be adopted; their oscillation processes are all carried out and output with a 50% duty cycle for symmetric sinusoidal or cosinusoidal varying voltage or current; and their switching is carried out using zero-current topology technology. An active differentiator unit 25 can be adopted to track the frequency of the series LC oscillator for easy control and adjustment.

[0103] Yet another embodiment of the present application also proposes a control method for an aerosol generating device, wherein the aerosol generating device is driven by the above LCC oscillator 24 or a similar series LC oscillator to heat the sensor 30. The method steps are as follows Figure 9 as shown, and include the following steps:

[0104] S100, detecting the rate of change of the oscillation voltage of the LCC oscillator 24 or the series LC oscillator;

[0105] S200, comparing the rate of change of the oscillation voltage with a preset value, and generating a high-level signal when it is higher than the preset value;

[0106] S300, calculating the oscillation frequency of the LCC oscillator 24 or the series LC oscillator by detecting the interval time of the high-level signal;

[0107] S400, further, the oscillation frequency of the LCC oscillator 24 or the series LC oscillator can be further adjusted by the MCU controller 21 to be the same as or basically close to the preset frequency.

[0108] By tracking and detecting the frequency and adjusting it in real time, the oscillation frequency is made the same as or basically close to the preset frequency, thereby maximizing the efficiency.

[0109] It should be noted that the present application provides preferred embodiments in the description and drawings of the present application, but is not limited to the embodiments described in this specification. Further, for those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present application.

Claims

1. An aerosol generating device configured to heat an aerosol generating article to generate an aerosol for inhalation; characterized in that, Comprising: A sensor configured to be penetrated by a changing magnetic field to generate heat for heating an aerosol generating article; A series LC oscillator or a series LCC oscillator having an inductor coil, configured to direct a changing current to flow through the inductor coil to drive the inductor coil to generate a changing magnetic field; A circuit configured to determine the oscillation frequency of the series LC oscillator or the series LCC oscillator according to the change rate of the oscillation voltage of the series LC oscillator or the series LCC oscillator; The circuit includes: An active differentiation unit configured to detect the change rate of the oscillation voltage of the series LC oscillator or the series LCC oscillator and output a high-level signal when the change rate of the oscillation voltage is greater than a preset threshold; A controller configured to determine the oscillation frequency of the series LC oscillator or the series LCC oscillator according to the interval time of the high-level signal.

2. The aerosol generating device according to claim 1, characterized in that, The active differentiation unit includes: an active differentiation module and a comparator; wherein, The active differentiation module is configured to detect the change rate of the oscillation voltage of the series LC oscillator or the series LCC oscillator; The comparator is configured to perform a comparison operation on the change rate of the oscillation voltage with a preset threshold and output a high-level signal to the controller when the change rate of the oscillation voltage is greater than the preset threshold.

3. The aerosol generating device according to claim 2, characterized in that, The active differentiation module includes: a first capacitor, a first resistor, a second capacitor, a second resistor, and an operational amplifier; wherein, A first end of the first capacitor is connected to the series LC oscillator or the series LCC oscillator, and a second end is connected to a first end of the first resistor; A first input terminal of the operational amplifier is connected to a second end of the first resistor, and an output terminal is connected to the comparator; A first end of the second capacitor is connected to the second end of the first resistor, and a second end is connected to the output terminal of the operational amplifier; A first end of the second resistor is connected to the second end of the first resistor, and a second end is connected to the output terminal of the operational amplifier.

4. The aerosol generating device according to claim 2, wherein, The active differentiation unit further includes: An access module including: a first diode, a third resistor, and a fourth resistor; wherein, A first end of the first diode is connected to the series LC oscillator or the series LCC oscillator, and a second end is connected to a first end of the third resistor, and is configured to only allow current to flow from the series LC oscillator or the series LCC oscillator to the third resistor; A second end of the third resistor is connected to the active differentiation module; A first end of the fourth resistor is connected to the second end of the third resistor, and a second end is grounded.

5. The aerosol generating device according to claim 4, wherein, The access module further includes: a voltage stabilizing diode; a first end of the voltage stabilizing diode is connected to the second end of the third resistor, and a second end is connected to the second end of the fourth resistor.

6. The aerosol generating device according to any one of claims 2 to 5, characterized in that, The preset threshold is the output value of the active differentiation module when the change rate of the oscillation voltage is 0.

7. The aerosol generating device according to any one of claims 1 to 5, characterized in that, The controller is configured to adjust the oscillation frequency of the series LC oscillator or the series LCC oscillator so that the oscillation frequency of the series LC oscillator or the series LCC oscillator is the same as or substantially close to a preset frequency.

8. A control method for an aerosol generating device, the aerosol generating device comprising: A sensor, configured to be penetrated by a changing magnetic field to generate heat for heating an aerosol generating article; A series LC oscillator or a series LCC oscillator having an inductor coil, configured to direct a changing current through the inductor coil to drive the inductor coil to generate a changing magnetic field; Characterized in that the method includes: Detecting a change rate of an oscillation voltage of the LCC oscillator or the series LC oscillator; Generating a high-level signal when the change rate of the oscillation voltage is higher than a preset value; Determining an oscillation frequency of the LCC oscillator or the series LC oscillator according to an interval time of the high-level signal.

9. The control method of the aerosol generating device according to claim 8, wherein, Further includes: Adjusting an oscillation frequency of the series LC oscillator or the series LCC oscillator so that the oscillation frequency of the series LC oscillator or the series LCC oscillator is the same as or substantially close to a preset frequency.

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