Aerosol generating device and control method therefor

Abstract

The present application provides an aerosol generating device and a control method therefor. The aerosol generating device comprises: a power supply circuit; a direct current / alternating current (DC / AC) inverter, comprising a class-E power amplifier, the class-E power amplifier comprising a transistor switch and an LC load network composed of a capacitor and an inductor, and the inductor being inductively coupled to a susceptor to heat an aerosol forming substrate so as to generate an aerosol; and a controller, configured to determine an apparent ohmic resistance on the basis of a DC power supply voltage and DC current outputted by the power supply circuit to the DC / AC inverter during operation, and further configured to monitor a change in the apparent ohmic resistance, and when the apparent ohmic resistance changes, to adjust the frequency and duty cycle of a switching signal supplied to the transistor switch. According to the aerosol generating device and the control method therefor, by monitoring the change in the apparent ohmic resistance, and when the apparent ohmic resistance changes, adjusting the frequency and duty cycle of the switching signal supplied to the transistor switch, the class-E power amplifier always operates in the optimal state.

Description

Aerosol generating device and control method thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 202410038019.9, filed with the Patent Office of China on January 10, 2024, entitled “Aerosol Generating Device and Control Method Thereof,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments of the present application relate to the field of electronic atomization technology, and in particular to an aerosol generating device and a control method thereof. Background Art

[0004] An existing aerosol-generating device uses a Class E power amplifier, which causes an inductor to generate a varying magnetic field, which in turn causes a receptor to heat the aerosol to form a matrix. Class E power amplifiers offer high operating frequencies and high efficiency, using fewer components and reducing product size. However, when the load fluctuates, the operating waveforms of the transistor switches in the Class E power amplifier drastically change, preventing it from operating in an ideal state in real time, significantly limiting its application.

[0005] Application Contents

[0006] The present application provides an aerosol generating device and a control method thereof, so as to provide a real-time variable zero position for a class E power amplifier in situations where the load is variable, so that the amplifier can operate in an ideal state in real time.

[0007] Based on the above technical problems, the present application provides an aerosol generating device, comprising:

[0008] A power supply circuit, used for providing a DC power supply voltage;

[0009] a DC / AC inverter connected to a power circuit; the DC / AC inverter including a class E power amplifier including a transistor switch and an LC load network formed by a capacitor and an inductor; wherein the inductor is inductively coupled to the susceptor to heat the aerosol-forming substrate to generate the aerosol;

[0010] The controller is configured to determine, during operation, an apparent ohmic resistance based on a DC supply voltage and a DC current output by the power circuit to the DC / AC inverter; the controller is further configured to monitor changes in the apparent ohmic resistance and adjust a frequency and a duty cycle of a switching signal supplied to the transistor switch when the apparent ohmic resistance changes.

[0011] In some embodiments, the controller is configured to reduce the frequency of the switching signal of the transistor switch and increase the duty cycle of the switching signal of the transistor switch when a decrease in the apparent ohmic resistance is monitored; or, when an increase in the apparent ohmic resistance is monitored, increase the frequency of the switching signal of the transistor switch and reduce the duty cycle of the switching signal of the transistor switch.

[0012] In some embodiments, the power supply circuit is configured to provide a variable DC supply voltage, and the controller is further configured to control the power supply circuit to adjust the DC supply voltage when the apparent ohmic resistance changes.

[0013] In some embodiments, the controller is configured to control the power supply circuit to reduce the DC supply voltage when monitoring that the apparent ohmic resistance decreases; or to control the power supply circuit to increase the DC supply voltage when monitoring that the apparent ohmic resistance increases.

[0014] In some embodiments, the power supply circuit includes a DC-DC conversion circuit and a regulation circuit;

[0015] The DC-DC conversion circuit includes an input terminal electrically connected to the battery cell, an output terminal for outputting a DC supply voltage, and a feedback terminal;

[0016] The regulation circuit is configured to accept control of the controller, so that the feedback end of the DC-DC conversion circuit generates a regulation signal, so that the DC-DC conversion circuit responds to the regulation signal and converts the cell voltage into a corresponding DC supply voltage.

[0017] In some embodiments, the aerosol generating device further comprises a voltage detection circuit for detecting the DC supply voltage provided by the power supply circuit.

[0018] In some embodiments, the aerosol generating device further comprises a current detection circuit for detecting the DC current drawn from the power circuit.

[0019] In some embodiments, the controller is further configured to determine a temperature of the susceptor based on the apparent ohmic resistance.

[0020] In some embodiments, the controller is further configured to determine whether the apparent ohmic resistance decreases or increases to a first predetermined resistance threshold, and adjust the frequency and duty cycle of the switching signal supplied to the transistor switch according to the determination result.

[0021] In some embodiments, the controller is further configured to output a switching signal having a first frequency and / or a first duty cycle during a first time period within a heating cycle so that the apparent ohmic resistance remains near a second preset resistance threshold; and to output a switching signal having a second frequency and / or a second duty cycle during a second time period within a heating cycle so that the apparent ohmic resistance remains near a third preset resistance threshold.

[0022] Another aspect of the present application provides a method for controlling an aerosol generating device, the aerosol generating device comprising:

[0023] A power supply circuit, used for providing a DC power supply voltage;

[0024] a DC / AC inverter connected to a power circuit; the DC / AC inverter including a class E power amplifier including a transistor switch and an LC load network formed by a capacitor and an inductor; wherein the inductor is inductively coupled to the susceptor to heat the aerosol-forming substrate to generate the aerosol;

[0025] The above methods include:

[0026] During operation, the apparent ohmic resistance is determined based on the DC supply voltage and the DC current output by the power supply circuit to the DC / AC inverter;

[0027] Changes in the apparent ohmic resistance are monitored, and when the apparent ohmic resistance changes, the frequency and duty cycle of the switching signal supplied to the transistor switch are adjusted.

[0028] The aerosol generating device and control method described above monitor changes in apparent ohmic resistance and, when the apparent ohmic resistance changes, adjust the frequency and duty cycle of the switching signal supplied to the transistor switch. This ensures that the Class E power amplifier always operates in an optimal state, i.e., the drain voltage of the transistor switch meets the zero voltage turn-on and zero voltage derivative turn-on conditions, thereby improving the efficiency of the entire device. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0030] FIG1 is a schematic diagram of an aerosol generating device provided in an embodiment of the present application;

[0031] FIG2 is a schematic diagram of another aerosol generating device provided in an embodiment of the present application;

[0032] FIG3 is a circuit diagram of a Class E power amplifier provided in an embodiment of the present application;

[0033] FIG4 is a schematic diagram of a current detection circuit provided in an embodiment of the present application;

[0034] FIG5 is a schematic diagram of a power supply circuit provided in an embodiment of the present application;

[0035] 6 is a schematic diagram of waveforms of gate voltage, drain voltage, and current of a transistor switch provided in an embodiment of the present application;

[0036] 7 is a schematic diagram of waveforms of gate voltage and drain voltage of a transistor switch under an apparent ohmic resistance according to an embodiment of the present application;

[0037] 8 is a schematic diagram of waveforms of gate voltage and drain voltage of a transistor switch under another apparent ohmic resistance provided in an embodiment of the present application;

[0038] 9 is another waveform diagram of the gate voltage and drain voltage of a transistor switch under another apparent ohmic resistance provided by an embodiment of the present application;

[0039] FIG10 is a schematic diagram of waveforms of a gate voltage and a drain voltage of a transistor switch under a power supply voltage according to an embodiment of the present application;

[0040] 11 is a schematic diagram of waveforms of a gate voltage and a drain voltage of a transistor switch under another power supply voltage provided in an embodiment of the present application;

[0041] FIG12 is a schematic diagram of a temperature versus time curve of a susceptor provided in an embodiment of the present application;

[0042] FIG13 is a flow chart of a control method for an aerosol generating device according to an embodiment of the present application. DETAILED DESCRIPTION

[0043] In order to facilitate the understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on the other element, or there can be one or more centered elements therebetween. When an element is described as "connected to" another element, it can be directly connected to the other element, or there can be one or more centered elements therebetween. The terms "upper", "lower", "left", "right", "inside", "outside" and similar expressions used in this specification are for illustrative purposes only.

[0044] Unless otherwise defined, all technical and scientific terms used in this specification have the same meanings as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification and in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the relevant listed items.

[0045] FIG1 is a schematic diagram of an aerosol generating device provided in one embodiment of the present application.

[0046] As shown in FIG. 1 , the aerosol generating device includes an atomizer 10 and a power supply assembly 20 .

[0047] In one example, the atomizer 10 is removably connected to the power supply assembly 20 , and the atomizer 10 and the power supply assembly 20 may be snap-connected, magnetically connected, etc. In another example, it is also feasible that the atomizer 10 and the power supply assembly 20 are integrally formed.

[0048] The atomizer 10 includes a carrier or container for a liquid aerosol-forming substrate, and the susceptor 11 may be incorporated into the carrier or container. For example, the container for the liquid aerosol-forming substrate may have a liquid storage chamber, and the susceptor 11 may be mounted within the container. The susceptor 11 is fixed within the container, facilitating more efficient coupling with the inductor 21 when the atomizer 10 is coupled to the power supply assembly 20.

[0049] The susceptor 11 is configured to be coupled with the inductor 21 and to generate heat when penetrated by the changing magnetic field, thereby heating the liquid aerosol-forming matrix, causing at least one component of the liquid aerosol-forming matrix to volatilize and form an aerosol for inhalation.

[0050] The susceptor 11 may be in direct contact with the liquid aerosol-forming substrate in the liquid storage chamber, or the susceptor 11 may be in indirect contact with the liquid aerosol-forming substrate. For example, a wicking material may be provided between the susceptor 11 and the liquid storage chamber to transfer the liquid aerosol-forming substrate to the susceptor 11. Optional wicking materials include porous materials or fibrous materials.

[0051] The sensor 11 can be made of at least one of the following materials: aluminum, iron, nickel, copper, bronze, cobalt, ordinary carbon steel, stainless steel, ferritic stainless steel, martensitic stainless steel or austenitic stainless steel.

[0052] The power supply assembly 20 includes an inductor 21 , a circuit 22 , and a battery cell 23 .

[0053] The inductor 21 generates a changing magnetic field under an alternating current. The inductor 21 includes but is not limited to an induction coil.

[0054] The circuit 22 may control the overall operation of the aerosol generating device. The circuit 22 controls not only the operation of the battery cell 23 and the inductor 21 , but also the operation of other components in the aerosol generating device.

[0055] The battery cell 23 provides power for operating the aerosol generating device and can be a rechargeable battery cell or a disposable battery cell.

[0056] FIG2 is a schematic diagram of an aerosol generating device provided in another embodiment of the present application.

[0057] As shown in Figure 2, the aerosol generating device includes:

[0058] A chamber in which a solid aerosol-forming substrate is removably received; the solid aerosol-forming substrate may be part of an aerosol-generating article A, such as a cigarette.

[0059] The receptor 110, at least a portion of which extends within the chamber and is configured to be coupled to the inductor 210, generates heat when penetrated by the changing magnetic field, thereby heating the solid aerosol-forming matrix, causing at least one component of the solid aerosol-forming matrix to volatilize and form an aerosol for inhalation.

[0060] In one example, the susceptor 110 is generally pin-shaped or blade-shaped, which is advantageous for insertion into a solid aerosol-forming substrate. Furthermore, the susceptor 110 may have a length of approximately 12 mm, a width of approximately 4 mm, and a thickness of approximately 0.5 mm, and may be made of grade 430 stainless steel (SS430). Alternatively, the susceptor 110 may have a length of approximately 12 mm, a width of approximately 5 mm, and a thickness of approximately 0.5 mm, and may be made of grade 430 stainless steel (SS430).

[0061] In another example, the susceptor 110 may be configured in a cylindrical or tubular shape; when in use, its interior space forms a chamber for receiving the solid aerosol-forming substrate, and generates an aerosol for inhalation by heating the outer periphery of the solid aerosol-forming substrate. These susceptors may also be made of grade 420 stainless steel (SS420) or an iron / nickel alloy (such as Permalloy).

[0062] The inductor 210 is used to generate a changing magnetic field under an alternating current. Depending on the configuration of the product during use, the inductor 210 may include a cylindrical inductor coil wound in a spiral shape.

[0063] The circuit 220 is electrically connected to the battery cell 230 and is used to convert the direct current output from the battery cell 230 into an alternating current with a suitable frequency and then supply the alternating current to the inductor 210 .

[0064] The battery cell 230 provides power for operating the aerosol generating device. The battery cell 230 may be a rechargeable battery cell or a disposable battery cell.

[0065] Based on the above-mentioned aerosol generating device, FIG3 to FIG5 are schematic diagrams showing basic components of an embodiment of a circuit.

[0066] As shown in FIG3 , the circuit includes a DC / AC inverter connected to a power circuit that provides a DC supply voltage V_DC. In this embodiment, the DC / AC inverter includes a Class E power amplifier, i.e., a resonant switching power amplifier, comprising the following components: a transistor switch Q1 comprising a field-effect transistor, such as a metal oxide semiconductor field-effect transistor (MOSFET); a transistor switch drive circuit K1, which, under the control of a controller, can supply a switching signal with a certain frequency and duty cycle to the transistor switch Q1; and an LC load network comprising a capacitor C1, a capacitor C2, and an inductor L2. Inductor L2 can, for example, correspond to inductor 21 shown in FIG1 or inductor 210 shown in FIG2 . Furthermore, a DC-fed choke L1 is provided for supplying the DC supply voltage V_DC from the power circuit. The figure also shows an ohmic resistance R representing the total equivalent resistance or total resistive load, which in operation may include, for example, the ohmic resistance of the inductor L2 and the ohmic resistance of the susceptor 11 shown in FIG. 1 , or the ohmic resistance of the inductor L2 and the ohmic resistance of the susceptor 110 shown in FIG. 2 .

[0067] The controller can be configured to determine the apparent ohmic resistance (hereinafter represented by Ra) by the DC supply voltage of the power supply circuit and by the DC current drawn from the power supply circuit during operation, that is, to determine the apparent ohmic resistance based on the DC supply voltage and the DC current output by the power supply circuit to the DC / AC inverter during operation.

[0068] The apparent ohmic resistance Ra can be used to determine the temperature of the sensor. That is, the apparent ohmic resistance Ra indicates the temperature of the sensor and, therefore, the temperature of the aerosol-forming substrate. The apparent ohmic resistance Ra can increase or decrease with increasing temperature; it can also increase and then decrease, or decrease and then increase, depending on the material properties of the sensor. For example, in a laminate of grade 430 stainless steel and Permalloy, the apparent ohmic resistance Ra increases when the temperature rises to 250°C, and then begins to decrease with further heating. By utilizing the Curie temperature characteristics of metallic magnetic materials, non-contact temperature control can be achieved; that is, without directly measuring the sensor temperature, the current input to the inverter and / or the magnitude of the inverter's resonant voltage can be used to determine the current temperature of the sensor.

[0069] In actual operation, both the DC supply voltage and the DC current drawn from the power circuit can be measured to determine the apparent ohmic resistance Ra. When the power circuit provides a fixed DC supply voltage, only the DC current drawn from the power circuit can be measured. Figure 4 shows a current detection circuit for detecting the DC current drawn from the power circuit. The current detection circuit mainly includes:

[0070] Voltage detection chip U7 and sampling resistor R33. One end of the sampling resistor R33 is electrically connected to the power supply circuit, and the other end of the sampling resistor R33 is electrically connected to the DC feed choke L1 (shown as L1_OUT in the figure). Pin 4 of the current detection chip U7 is connected to one end of the sampling resistor R33, and pin 5 of the current detection chip U7 is electrically connected to the other end of the sampling resistor R33. Pin 6 of the voltage detection chip U7 outputs the sampled voltage across the resistor R33 to the controller (shown as ADC_OUT in the figure). Based on the voltage across the resistor R33 and the resistance value of the resistor R33, the controller can determine the magnitude of the DC current drawn from the power supply circuit. The resistor R12 and capacitor C19 in the figure constitute a filter circuit to filter the sampled voltage across the resistor R33.

[0071] FIG5 is a power supply circuit provided by an embodiment of the present application, which can provide a variable DC power supply voltage for a Class E power amplifier. As shown in FIG5 , the power supply circuit includes:

[0072] The DC-DC converter circuit 301 consists of a power supply chip U4 and its peripheral circuits. The power supply chip U4 primarily includes an input terminal (pin 8 in the figure) electrically connected to the battery cell, an output terminal (pin 16 in the figure) that outputs the DC supply voltage V_DC, and a feedback terminal (pin 4 in the figure). The power supply chip U4 can be either a step-up or step-down chip; in this example, a step-down chip is used.

[0073] The regulating circuit 302 is composed of a potentiometer U12 and its peripheral circuits. The regulating circuit 302 is configured to accept the control of the controller, so that the feedback end of the DC-DC conversion circuit 301 generates a regulating signal, so that the DC-DC conversion circuit 301 responds to the regulating signal and converts the cell voltage BAT_IN into the corresponding DC power supply voltage V_DC. Specifically, the potentiometer chip U12 is accessed and controlled using the I2C protocol, which can adjust the resistance value connected between pins 5 and 6, so that the feedback end of the DC-DC conversion circuit 301 generates a regulating signal. The size of each level of regulation is determined by the number of bits of the chip, such as 8 bits / 10 / 12 bits, etc., that is, the maximum resistance value of the potentiometer is divided into 28 / 210 / 212.

[0074] Furthermore, a voltage detection circuit 303 composed of a resistor R28, a resistor R39, and a capacitor C45 is included. The voltage detection circuit 303 is used to detect the current DC supply voltage to determine whether it is the required DC supply voltage. If it is not the required DC supply voltage, the potentiometer chip U12 is controlled until the current DC supply voltage reaches the required DC supply voltage. Among them, the resistor R28 and the resistor R39 form a voltage divider circuit, and the capacitor C45 is used to filter the voltage divider signal.

[0075] Please refer to Figure 3 again. The output power P of the Class E power amplifier is 0.5678×V_DC. 2 / R. When transistor switch Q1 (assuming it's an NMOS transistor) is turned on, if the drain voltage of transistor switch Q1 just reaches the zero axis, the drain voltage of transistor switch Q1 meets the zero voltage turn-on and zero voltage derivative turn-on conditions. At this time, voltage Vds and current Ids do not overlap, and the power consumption of transistor switch Q1 is zero. The Class E power amplifier has the highest efficiency, and in practice, the efficiency of a Class E power amplifier can reach 95%. This is specifically shown in Figure 6:

[0076] (a) The drain voltage of transistor switch Q1 satisfies the zero voltage turn-on and zero voltage derivative turn-on conditions, and the Class E power amplifier operates optimally. At this point, the ohmic resistor R is of the appropriate size. In the figure, Ug is the gate voltage, Vs is the drain voltage, and Is is the drain current.

[0077] (b) When the value of the ohmic resistor R is too large, the output power of the class E power amplifier is too small and it operates in a quasi-optimal state. The lowest point of the drain voltage of the transistor switch Q1 appears below the zero axis (the horizontal axis in the figure).

[0078] (c) When the value of the ohmic resistor R is relatively small, the output power of the class E power amplifier is relatively high and it operates in an unregulated state. At this time, the drain voltage of the transistor switch Q1 is above the zero axis.

[0079] From the above, it can be seen that the power loss of the Class E power amplifier is small or close to zero only when it is adapted to a load of appropriate size. When the load becomes larger or smaller, the actual efficiency of the Class E power amplifier will be reduced.

[0080] In one example, the controller is configured to monitor changes in the apparent ohmic resistance Ra and, when the apparent ohmic resistance Ra changes, adjust the frequency and duty cycle of the switching signal supplied to the transistor switch Q1. This ensures that the Class E power amplifier always operates in an optimal state, i.e., the drain voltage of the transistor switch Q1 meets the zero voltage turn-on and zero voltage derivative turn-on conditions, thereby improving overall efficiency.

[0081] As shown in Figure 7 , when the apparent resistance Ra is 0.6 ohms, the switching signal supplied to transistor switch Q1 (denoted by VG2 in the figure) has a frequency of 6.82 MHz and a duty cycle of 50%, respectively. At this point, it can be observed that the drain voltage waveform of transistor switch Q1 is relatively ideal, meeting both the zero voltage turn-on and zero voltage derivative turn-on conditions.

[0082] As shown in Figure 8 , as the heating temperature rises, the apparent ohmic resistance Ra decreases to 0.5 ohms. If the frequency and duty cycle of the switching signal supplied to transistor switch Q1 remain unchanged, Figure 8 shows that the zero point of the drain voltage of transistor switch Q1 is -0.9V, and transistor switch Q1 is not turned on at this moment. Therefore, the product of the voltage and current across the drain and source of transistor switch Q1 is much greater than 0, resulting in significant losses in transistor switch Q1, severe heat generation, high operating temperatures, and reduced efficiency.

[0083] As shown in FIG9 , when the apparent ohmic resistance Ra is reduced to 0.5 ohms, the frequency and duty cycle of the switching signal supplied to the transistor switch Q1 are adjusted, for example, to 6.676 MHz and 53%. FIG9 shows that the drain voltage waveform of the transistor switch Q1 satisfies both the zero voltage turn-on and zero voltage derivative turn-on conditions.

[0084] In one example, the controller is configured to reduce the frequency of the switching signal of the transistor switch Q1 and increase the duty cycle of the switching signal of the transistor switch Q1 when the apparent ohmic resistance Ra is monitored to decrease; or, when the apparent ohmic resistance Ra is monitored to increase, increase the frequency of the switching signal of the transistor switch Q1 and reduce the duty cycle of the switching signal of the transistor switch Q1.

[0085] In one example, the controller is further configured to control the power supply circuit to adjust the DC supply voltage when the apparent ohmic resistance Ra changes, thereby adjusting the heating power and improving the efficiency of the entire machine.

[0086] In a specific example, the controller is configured to control the power supply circuit to reduce the DC supply voltage when monitoring the apparent ohmic resistance Ra to decrease; or to control the power supply circuit to increase the DC supply voltage when monitoring the apparent ohmic resistance Ra to increase.

[0087] As shown in FIG. 10 , when the apparent ohmic resistance Ra is 0.5 ohm, the frequency and duty cycle of the switching signal supplied to the transistor switch Q1 are 6.676 MHz and 53%, the power supply voltage is 3.3 V, the power supply current is approximately 4.2 A, and the power supply power is 3.3 V*4.2 A=13.9 W.

[0088] As shown in Figure 11, if the apparent ohmic resistance Ra, the frequency, and the duty cycle of the switching signal supplied to transistor switch Q1 remain the same as in Figure 10, and the power supply voltage is adjusted to 2.5V, the power supply current is approximately 3.3A, and the power supply power is 2.5V * 3.3A = 8.25W. In other words, by reducing the power supply voltage, the heating power is reduced, maintaining a lower power heating, reducing the heat generated by transistor switch Q1, and further improving the efficiency of the entire device.

[0089] In one example, the controller is further configured to adjust the frequency and duty cycle of the switching signal supplied to the transistor switch Q1 if the apparent ohmic resistance Ra reaches a predetermined resistance threshold. Specifically, the controller determines whether the apparent ohmic resistance Ra decreases or increases to a first predetermined resistance threshold, and adjusts the frequency and duty cycle of the switching signal supplied to the transistor switch Q1 based on the determination result.

[0090] In one example, the controller is further configured to output a switching signal having a first frequency and / or a first duty cycle during a first time period within a heating cycle to maintain the apparent ohmic resistance Ra near a second preset resistance threshold; and to output a switching signal having a second frequency and / or a second duty cycle during a second time period within the heating cycle to maintain the apparent ohmic resistance Ra near a third preset resistance threshold. The second preset resistance threshold may be greater than or less than the third preset resistance threshold.

[0091] FIG12 is a schematic diagram of a temperature-time curve of a receptor provided in an embodiment of the present application. As shown in FIG12 , a puff period of the aerosol generating device includes three time periods, namely, time period t0 to t1, time period t1 to t2, and time period t2 to t3.

[0092] During the time period t0-t1, the temperature of the susceptor rapidly rises from the initial temperature T0 to a target temperature T1, for example, 250°C. Typically, the target temperature T1 is the maximum temperature during a puff of the electronic atomization device 100. The duration of the time period t0-t1 is less than 1 second, such as 0.2 seconds, 0.4 seconds, 0.6 seconds, 0.8 seconds, etc., to quickly respond to the user's puff. During this stage, the susceptor needs to be able to quickly heat up to the desired temperature to heat the liquid matrix as quickly as possible to produce an aerosol.

[0093] During the time period t1 to t2 , the temperature of the susceptor 11 drops from the temperature T1 to the temperature T2 , and the temperature of the susceptor 11 is maintained at T2 .

[0094] During the time period t2 to t3 , the temperature of the susceptor 11 drops from the temperature T2 to the temperature T3 , and the temperature of the susceptor 11 is maintained at T3 .

[0095] In actual operation, the preset resistance thresholds corresponding to the three time periods, the frequency and duty cycle of the switching signal of the transistor switch Q1, and other data can be stored in the controller, so that the aerosol generating device operates according to the predetermined desired temperature curve. For example:

[0096] When heating is started, the DC supply voltage provided by the power supply circuit is controlled to be a first DC supply voltage, the frequency of the switching signal supplied to the transistor switch Q1 is controlled to be a first frequency, and the duty cycle of the switching signal supplied to the transistor switch Q1 is controlled to be a first duty cycle, so that the temperature of the sensor rises rapidly from the initial temperature T0 to the target temperature T1.

[0097] The change in the apparent ohmic resistance Ra is monitored. When the apparent ohmic resistance Ra reaches a predetermined resistance threshold corresponding to the target temperature T1, the DC supply voltage provided by the power supply circuit is controlled to be a second DC supply voltage that is lower than the first DC supply voltage, i.e., the heating power is reduced. The frequency of the switching signal supplied to the transistor switch Q1 is controlled to be a second frequency, and the duty cycle of the switching signal supplied to the transistor switch Q1 is controlled to be a second duty cycle, so that the temperature of the susceptor 11 drops from temperature T1 to temperature T2, and the temperature of the susceptor 11 is maintained at T2.

[0098] During the time period t2 to t3, the DC supply voltage provided by the power supply circuit is controlled to be a third DC supply voltage that is lower than the second DC supply voltage, i.e., the heating power is further reduced. The frequency of the switching signal supplied to the transistor switch Q1 is controlled to be a third frequency, and the duty cycle of the switching signal supplied to the transistor switch Q1 is controlled to be a third duty cycle, so that the temperature of the susceptor 11 drops from temperature T2 to temperature T3, and the temperature of the susceptor 11 is maintained at T3.

[0099] FIG13 is a flow chart of a control method for an aerosol generating device according to an embodiment of the present application. The control method includes the following steps:

[0100] S11, determining an apparent ohmic resistance based on a DC supply voltage and a DC current output by the power supply circuit to the DC / AC inverter during operation;

[0101] S12. Monitor the change of the apparent ohmic resistance, and when the apparent ohmic resistance changes, adjust the frequency and duty cycle of the switching signal supplied to the transistor switch.

[0102] In one example, when the apparent ohmic resistance is monitored to decrease, the frequency of the switching signal of the transistor switch is reduced and the duty cycle of the switching signal of the transistor switch is increased; or, when the apparent ohmic resistance is monitored to increase, the frequency of the switching signal of the transistor switch is increased and the duty cycle of the switching signal of the transistor switch is reduced.

[0103] In one example, when the apparent ohmic resistance changes, the power supply circuit is controlled to adjust the DC supply voltage.

[0104] In one example, when the apparent ohmic resistance is monitored to decrease, the power supply circuit is controlled to decrease the DC supply voltage; or when the apparent ohmic resistance is monitored to increase, the power supply circuit is controlled to increase the DC supply voltage.

[0105] In one example, the temperature of the susceptor is determined based on the apparent ohmic resistance.

[0106] In one example, it is determined whether the apparent ohmic resistance decreases or increases to a first predetermined resistance threshold, and the frequency and duty cycle of the switching signal supplied to the transistor switch are adjusted according to the determination result.

[0107] In one example, a switching signal having a first frequency and / or a first duty cycle is output during a first time period within a heating cycle so that the apparent ohmic resistance remains near a second preset resistance threshold; and a switching signal having a second frequency and / or a second duty cycle is output during a second time period within a heating cycle so that the apparent ohmic resistance remains near a third preset resistance threshold.

[0108] It should be noted that the preferred embodiments of the present application are given in the specification and drawings of this application. However, the present application can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments are not intended to be additional limitations on the content of this application. The purpose of providing these embodiments is to make the understanding of the disclosure of this application more thorough and comprehensive. In addition, the above-mentioned technical features can be combined with each other to form various embodiments not listed above, which are all considered to be within the scope of the description of this application; further, it is obvious to those skilled in the art that improvements or changes can be made based on the above description, and all such improvements and changes should fall within the scope of protection of the claims attached to this application.

Claims

1. An aerosol generating device, characterized in that, Comprising: A power supply circuit for providing a DC supply voltage; A DC / AC inverter connected to the power supply circuit; The DC / AC inverter includes a class-E power amplifier, and the class-E power amplifier includes a transistor switch and an LC load network composed of a capacitor and an inductor; wherein, the inductor is inductively coupled to a susceptor to heat an aerosol-forming substrate to generate an aerosol; A controller configured to determine an apparent ohmic resistance based on the DC supply voltage and the DC current output from the power supply circuit to the DC / AC inverter during operation; the controller is further configured to monitor a change in the apparent ohmic resistance and, when the apparent ohmic resistance changes, adjust the frequency and duty cycle of a switching signal supplied to the transistor switch.

2. The aerosol generating device according to claim 1, wherein, The controller is configured to decrease the frequency of the switching signal of the transistor switch and increase the duty cycle of the switching signal of the transistor switch when it monitors a decrease in the apparent ohmic resistance; or, to increase the frequency of the switching signal of the transistor switch and decrease the duty cycle of the switching signal of the transistor switch when it monitors an increase in the apparent ohmic resistance.

3. The aerosol generating device according to claim 1, characterized in that, The power supply circuit is configured to be able to provide a variable DC supply voltage, and the controller is further configured to control the power supply circuit to adjust the DC supply voltage when the apparent ohmic resistance changes.

4. The aerosol generating device according to claim 3, wherein, The controller is configured to control the power supply circuit to decrease the DC supply voltage when it monitors a decrease in the apparent ohmic resistance; or, to control the power supply circuit to increase the DC supply voltage when it monitors an increase in the apparent ohmic resistance.

5. The aerosol generating device according to claim 3, wherein The power supply circuit includes a DC-DC conversion circuit and a regulation circuit; The DC-DC conversion circuit includes an input terminal electrically connected to a battery cell, an output terminal for outputting a DC supply voltage, and a feedback terminal; The regulation circuit is configured to receive control from the controller so that a regulation signal is generated at the feedback terminal of the DC-DC conversion circuit, such that the DC-DC conversion circuit responds to the regulation signal and converts the battery cell voltage into a corresponding DC supply voltage.

6. The aerosol generating device according to claim 3, characterized in that It further includes a voltage detection circuit for detecting the DC supply voltage provided by the power supply circuit.

7. The aerosol generating device according to claim 1, characterized in that, It further includes a current detection circuit for detecting the DC current drawn from the power supply circuit.

8. The aerosol generating device according to claim 1, wherein The controller is further configured to determine the temperature of the susceptor based on the apparent ohmic resistance.

9. The aerosol generating device according to claim 1, characterized in that, The controller is further configured to determine whether the apparent ohmic resistance decreases or increases to a first preset resistance threshold, and adjust the frequency and duty cycle of the switching signal supplied to the transistor switch according to the determination result.

10. The aerosol generating device according to claim 1, wherein, The controller is further configured to output a switching signal having a first frequency or / and a first duty cycle during a first time period within a heating cycle to keep the apparent ohmic resistance near a second preset resistance threshold; And output a switching signal having a second frequency or / and a second duty cycle during a second time period within a heating cycle to keep the apparent ohmic resistance near a third preset resistance threshold.

11. A control method for an aerosol generating device, characterized in that, The aerosol generating device includes: A power supply circuit for providing a DC supply voltage; A DC / AC inverter, connected to the power supply circuit; the DC / AC inverter includes a class-E power amplifier, and the class-E power amplifier includes a transistor switch and an LC load network composed of a capacitor and an inductor; wherein, the inductor is inductively coupled to a receptor to heat an aerosol-forming substrate to generate an aerosol; The method includes: Determining an apparent ohmic resistance based on the DC supply voltage and the DC current output from the power supply circuit to the DC / AC inverter during operation; Monitoring the change of the apparent ohmic resistance, and when the apparent ohmic resistance changes, adjusting the frequency and duty cycle of the switching signal supplied to the transistor switch.

Images