Heating non-combustion smoking set and electromagnetic induction heating control method and device thereof

Abstract

The invention discloses a heating non-combustion smoking set and an electromagnetic induction heating control method and device thereof.A driving circuit of the heating non-combustion smoking set converts a power supply into a high-frequency power signal according to an excitation source so as to drive a resonance network to generate a high-frequency sine wave signal, and a metal induction piece induces the high-frequency sine wave signal to generate heat; the electromagnetic induction heating control method comprises the following steps: calibrating an excitation source input frequency; transmitting an excitation source with an initial frequency to a driving circuit at a first duty ratio, wherein the first duty ratio is lower than 50%; the working current of the resonance network is collected in real time, the input frequency of the excitation source is adjusted in a preset frequency range, the maximum value of the working current is found, the input frequency when the working current is maximum serves as the optimal input frequency, and the input frequency of the excitation source is adjusted to the optimal input frequency. The working frequency of the excitation source can be calibrated before the cigarette is formally heated, so that the working frequency is close to the resonant frequency of the resonant network, the resonant network is ensured to work in a resonant state, and the heating stability is high.

Description

Technical Field

[0001] The invention relates to a heat-not-burn smoking device, and in particular to electromagnetic induction heating control of the heat-not-burn smoking device. Background Art

[0002] Traditional heat-not-burn devices generally heat cigarettes by metal resistance wire heating, thick film heating, thin film heating, and ceramic heating element heating. When in use, insert the heater into the cigarette, then start the device to heat the cigarette. The device detects the change in the resistance of the heater to perform closed-loop temperature control. This type of heat-not-burn device often has a short service life.

[0003] Based on the above shortcomings, the new generation of heat-not-burn tobacco products adopts electromagnetic induction heating technology. The electromagnetic heating coil of the electromagnetic transmitting device sends high-frequency AC signals to the heated metal induction parts. When the metal induction parts move in a changing magnetic field or in a non-uniform magnetic field, an induced electromotive force will be generated in the metal. Since the resistance of the metal is very small, even if the induced electromotive force is not very large, it can cause a strong current. Thus, a thermal effect is generated to heat the aerosol-generating product. This aerosol-generating product generally includes a power control module, a heating component, and a heating chamber. The power control module provides a high-frequency AC signal to the heating component. The heating chamber is used to accommodate the cigarette cartridge. The heating component includes an electromagnetic heating coil surrounding the outside of the heating chamber. The induced metal induction part is installed in the heating chamber or directly installed in the cigarette cartridge.

[0004] refer to Figure 1 , is the circuit diagram of the power control module. The power control module is a class E resonant topology high-frequency inverter circuit, including a drive circuit and a resonant network. The drive circuit includes an inductor L1, a capacitor C1, and a MOS tube Q1. The resonant network includes a capacitor C2 and an inductor L2. The drive circuit converts the power supply into a high-frequency power signal according to the excitation source input by the MOS tube Q1 to drive the resonant network to generate a high-frequency sine wave signal. The metal induction component R senses the high-frequency sine wave signal to generate heat to heat the cigarette. When working, the control unit sends a fixed-frequency excitation source Fin to the MOS tube Q1 to control the drive circuit to generate a fixed-frequency power signal. When adjusting the metal induction component R, it is only necessary to adjust the duty cycle of the excitation source Fin according to the sensed load resistance or working current. Among them, in order to make the heating stable, a frequency close to the resonant frequency of the resonant network is generally selected as the frequency of the excitation source. The frequency of the resonant network is determined by L2 and C2: So the excitation source Where L2 and C2 are fixed values.

[0005] However, for the following reasons:

[0006] 1. The inductance of the inductor L2 usually changes with the increase of temperature. For coil-type inductors, as the temperature increases, the resistance of the coil increases, resulting in a decrease in the inductance. This is caused by the temperature affecting the wire of the coil. For iron-core inductors, as the temperature increases, the magnetic permeability of the iron core changes, resulting in a change in the inductance.

[0007] 2. The capacitance value of capacitor C2 usually changes with the increase of temperature. This is because the dielectric constant and dielectric loss tangent of the capacitor material change under the influence of temperature. For aluminum electrolytic capacitors, the increase of temperature will cause the conductivity of the electrolyte to increase, thus leading to an increase in capacitance. For ferroelectric dielectric capacitors, the increase of temperature will cause the polarization effect of the ferroelectric material to change, thus leading to a change in capacitance.

[0008] 3. Manufacturing errors of components C2 and L2 themselves.

[0009] This will inevitably cause the frequency of the actual excitation source to shift relative to the frequency of the resonant network. Therefore, in existing heat-not-burn smoking devices, it is difficult to make the resonant network work in an ideal resonant state, and the heating stability is poor.

[0010] Therefore, there is an urgent need for a heating control method for a heat-not-burn smoking device that can solve the above problems. Summary of the invention

[0011] The purpose of the present invention is to provide an electromagnetic induction heating control method and device for heat-not-burn tobacco products, as well as a heat-not-burn tobacco product, which can calibrate the operating frequency of the excitation source before formally heating the cigarette to make it close to the resonant frequency of the resonant network, thereby ensuring that the resonant network operates in a resonant state and has high heating stability.

[0012] In order to achieve the above-mentioned purpose, the present invention provides an electromagnetic induction heating control method for heat-not-burn tobacco utensils, the heat-not-burn tobacco utensils comprising a driving circuit and a resonant network, the driving circuit converts a power supply into a high-frequency power supply signal according to an excitation source input by a control end to drive the resonant network to generate a high-frequency sine wave signal, and a metal induction component senses the high-frequency sine wave signal to generate heat, comprising the steps of calibrating the input frequency of the excitation source: delivering an excitation source of an initial frequency to the driving circuit at a first duty cycle so that the resonant network starts working, the first duty cycle being lower than 50%; collecting the working current of the resonant network in real time, adjusting the input frequency of the excitation source within a preset frequency range, finding the maximum value of the working current, and taking the input frequency at the maximum value of the working current as the optimal input frequency, and adjusting the input frequency of the excitation source to the optimal input frequency.

[0013] Preferably, the first duty cycle is greater than or equal to 1% and less than or equal to 15%. Of course, this is not limited to this, as long as the metal sensing element cannot be heated up to a preset value within a preset time, the preset time is a predetermined calibration time.

[0014] Preferably, the excitation source input frequency is calibrated according to an external control command, and / or the excitation source input frequency is calibrated each time the machine is turned on, and / or the excitation source input frequency is calibrated when the machine is turned on for the first time, and / or the excitation source input frequency is calibrated once after each preset number of turns on.

[0015] Preferably, the preset frequency range is 5 MHz to 7 MHz. Of course, it is not limited thereto, and the range value can be selected around the theoretical resonant frequency of the resonant network.

[0016] Preferably, after obtaining the optimal input frequency, the optimal input frequency is also recorded, and the optimal input frequency is used as the initial frequency of the excitation source during the next startup and calibration.

[0017] Preferably, when the maximum working current is found, it is also determined whether the maximum working current is within a preset current range. If so, the input frequency at the maximum working current is used as the optimal input frequency. If not, a fault signal is output and / or the excitation source input frequency is recalibrated until the optimal input frequency is within the preset current range or the calibration times exceed the preset times, then a fault signal is output and the power supply of the resonant network is turned off. This solution can effectively prevent incorrect calibration caused by system failure, drive circuit failure, or excessive temperature of the metal induction component.

[0018] Preferably, before calibrating the input frequency of the excitation source, the current temperature of the metal induction component is detected and acquired, and the input frequency of the excitation source is calibrated when the current temperature does not exceed a preset temperature value, and the calibration is stopped when the current temperature exceeds the preset temperature value.

[0019] Specifically, the preset current range is 2.5A-4.5A. The preset current is set based on the theoretical optimal working current. The theoretical optimal working current is generally in the middle of the preset current range or close to the middle of the preset current range. Of course, the preset current range is not limited to the above values. The theoretical optimal working current can be obtained through experimental testing or through a theoretical calculation formula.

[0020] Preferably, the input frequency of the excitation source is adjusted within a preset frequency range, and the steps for finding the maximum value of the working current are: adjusting the current input frequency in a first direction, and if the working current increases, continuing to adjust until the working current begins to decrease, so as to determine the maximum value of the working current; if the working current decreases, adjusting the current input frequency in a second direction opposite to the first direction, and if the working current increases, continuing to adjust until the working current begins to decrease, so as to determine the maximum value of the working current; if the working current still decreases, taking the initial working current as the maximum value of the working current.

[0021] Preferably, after calibrating the input frequency of the excitation source, the method further comprises the step of adjusting the duty cycle of the excitation source to a second duty cycle so that the metal induction element is quickly heated, wherein the first duty cycle is smaller than the second duty cycle. This solution enables the heat-not-burn smoking device to start normal operation directly after calibrating the frequency of the excitation source.

[0022] Specifically, the second duty cycle is greater than or equal to 90% and less than or equal to 98%.

[0023] Specifically, after adjusting the duty cycle of the excitation source to the second duty cycle, the method further includes the step of: adjusting the duty cycle of the excitation source so that the metal induction component is maintained at a target temperature.

[0024] More specifically, adjusting the duty cycle of the excitation source so that the metal induction part is maintained at the target temperature specifically includes: after adjusting the duty cycle of the excitation source to the second PWM duty cycle, finding the first current I1 at the inflection point of the first trough of the current change of the working current, and obtaining the second current I2 at the inflection point of the second peak of the current change; determining the target current according to the numerical values ​​of the first current I1 and the second current I2, the target current being greater than the first current I1 and less than the second current I2; and adjusting the duty cycle of the excitation source according to the target current. This solution can perform targeted temperature adjustment on metal induction parts of different specifications, with accurate temperature control and wide adaptability.

[0025] The present invention also provides an electromagnetic induction heating control device for heat-not-burn tobacco products, comprising: a current acquisition circuit for acquiring the working current of an electromagnetic generating device; one or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by one or more processors to implement the electromagnetic induction heating control method for heat-not-burn tobacco products as described above.

[0026] The present invention also provides a heat-not-burn tobacco device, comprising a power supply, a drive circuit, a resonant network and a control module, wherein the power supply outputs a DC power supply, the control module controls the duty cycle of an excitation source of the drive circuit, the drive circuit converts the DC power supply into an AC power signal based on the excitation source, the resonant network generates a high-frequency electromagnetic wave based on the power signal, a metal induction component induces the high-frequency electromagnetic wave to generate heat to heat the cigarette, and the control module comprises the electromagnetic induction heating control device of the heat-not-burn tobacco device as described above.

[0027] The present invention also provides a heat-not-burn tobacco device, comprising a power supply, a drive circuit, a resonant network and a control module, wherein the power supply outputs a DC power supply, the control module controls the duty cycle of the excitation source of the drive circuit, the drive circuit converts the DC power supply into an AC power signal according to the excitation source, the resonant network generates high-frequency electromagnetic waves according to the power signal, and a metal induction component induces the high-frequency electromagnetic waves to generate heat to heat the cigarette, the control module comprises an acquisition circuit and a control unit, the acquisition circuit acquires the working current of the resonant network, the control unit transmits an excitation source of an initial frequency to the drive circuit at a first duty cycle so that the resonant network starts working, adjusts the input frequency of the excitation source within a preset frequency range, finds the maximum value of the working current, and uses the input frequency at the maximum value of the working current as the optimal input frequency, and adjusts the input frequency of the excitation source to the optimal input frequency.

[0028] Compared with the prior art, the present invention operates at a relatively low duty cycle and adjusts the frequency of the excitation source before the heat-not-burn smoking device starts working so that the metal sensing component adjusts the frequency of the excitation source when the temperature is relatively low, thereby preventing the metal sensing component from overheating and affecting the detection result. The best input frequency of the excitation source is obtained by finding the best working current, making it as close as possible to the resonant frequency of the resonant network, adjusting the problem of the resonant frequency of the resonant network deviating from the working frequency of the excitation source due to long-term use and errors in the components themselves, ensuring that the resonant network operates in a resonant state, making the circuit close to a pure resistance working state, and having good heating stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is the circuit schematic diagram of the heat-not-burn smoking device.

[0030] Figure 2 It is a flow chart of the electromagnetic induction heating control method in Example 1 of the present invention.

[0031] Figure 3 It is a flow chart of the electromagnetic induction heating control method in Example 2 of the present invention.

[0032] Figure 4It is a flow chart of the electromagnetic induction heating control method in Example 3 of the present invention.

[0033] Figure 5 It is a structural diagram of the heat-not-burn smoking device of the present invention. DETAILED DESCRIPTION

[0034] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.

[0035] refer to Figure 1 and Figure 5 The present invention discloses a heat-not-burn smoking device 100, comprising a DC power supply VCC, a driving circuit 11, a resonant network 12, and a control module 30. The power supply VCC outputs a DC power supply. The control module 30 controls the duty cycle and input frequency of the excitation source Fin of the driving circuit 11. The driving circuit 11 converts the DC power supply into an AC power supply signal according to the excitation source Fin. The resonant network 12 generates a high-frequency electromagnetic wave according to the power supply signal. The metal induction member 20 senses the high-frequency electromagnetic wave and starts to generate heat to heat the cigarette 200. The metal induction member 20 can be installed in the heating cavity 41 of the heat-not-burn smoking device housing 40, or can be built into the cigarette 200, and is located in the heating cavity 41 as the cigarette 200 is inserted into the heating cavity 41.

[0036] refer to Figure 5 The heat-not-burn smoking device 100 further includes a battery 50, and the battery 50 is used to provide a power supply VCC.

[0037] refer to Figure 1 The control module 30 includes an acquisition circuit and a control unit. The acquisition circuit acquires the working current Ia of the resonant network 12. When calibrating the input frequency of the excitation source, the control unit transmits the excitation source Fin of the initial frequency to the driving circuit 11 at a first duty cycle, so that the resonant network 12 starts working and does not quickly heat the metal induction component 20. The control unit adjusts the input frequency of the excitation source Fin within a preset frequency range, searches for the maximum value of the working current Ia, and uses the input frequency when the working current Ia is at the maximum value as the optimal input frequency. The input frequency of the excitation source is adjusted to the optimal input frequency, so that the excitation source Fin is controlled to output at the optimal input frequency during operation, thereby completing the calibration of the input frequency of the excitation source Fin.

[0038] After completing the calibration of the input frequency of the excitation source Fin, the control unit can adjust the duty cycle of the excitation source Fin to a second duty cycle so that the resonant network can be heated quickly, and the duty cycle of the excitation source Fin can be adjusted in real time to maintain the metal sensing component 20 at a target temperature, and the first duty cycle is smaller than the second duty cycle.

[0039] Specifically, the control unit includes one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors to implement the electromagnetic induction heating control method.

[0040] Example 1, reference Figure 2 The electromagnetic induction heating control method specifically includes the step of calibrating the input frequency of the excitation source Fin: see the following steps S1 to S2.

[0041] S1 , delivering an excitation source Fin of an initial frequency to the driving circuit 11 at a first duty cycle to enable the resonant network 12 to start working, wherein the first duty cycle is lower than 50%.

[0042] Among them, if the metal sensing component 20 is built into the cigarette 200, the start of calibrating the input frequency of the excitation source Fin needs to be after the cigarette 200 is inserted into the heating chamber 41 of the heat-not-burn tobacco device to avoid the heat-not-burn tobacco device being in an unloaded state during calibration. That is to say, after turning on the power, if the input frequency of the excitation source Fin is to be calibrated, then after detecting that the cigarette 200 is inserted into the heat-not-burn tobacco device, the excitation source Fin with an initial frequency is started to be transmitted to the drive circuit 11 with a first duty cycle. If the metal sensing component 20 is installed in the heating chamber 41 of the heat-not-burn tobacco device, and the cigarette 200 does not have the metal sensing component 20, the calibration of the input frequency of the excitation source Fin can be started after the cigarette 200 is inserted into the heating chamber 41, or it can be started directly. If the cigarette 200 is not inserted into the heating chamber 41, the power supply to the induction network is stopped after the calibration of the input frequency of the excitation source Fin is completed (the power supply of the DC power supply is disconnected or the duty cycle is adjusted to 0). If the cigarette 200 is inserted into the heating chamber 41, after completing the calibration of the input frequency of the excitation source Fin, it can directly work to increase the duty cycle to the second duty cycle to heat the cigarette 200. At this time, the control module 30 transmits the excitation source Fin with a duty cycle of the second duty cycle and a frequency of the optimal input frequency to the drive circuit 11.

[0043] In this embodiment, the first duty cycle is greater than or equal to 1% and less than or equal to 15%.

[0044] The first duty cycle is preferably selected so that the resonant network 12 starts to work but does not effectively heat the metal sensing element 20, or in other words, the metal sensing element 20 cannot be heated to a preset value within a preset time, for example, cannot be heated to 100 degrees within 1 second.

[0045] S2, including: S21, adjusting the input frequency of the excitation source Fin within a preset frequency range to find the maximum value of the working current Ia, S22, taking the input frequency when the working current Ia is at the maximum value as the optimal input frequency, and adjusting the input frequency of the excitation source to the optimal input frequency, so as to control the excitation source Fin to output at the optimal input frequency.

[0046] The preset frequency range is 5 MHz to 7 MHz. Of course, other range values ​​can be selected as needed, and are not limited to the above data range. The preset frequency range is set around the ideal resonant frequency of the resonant network 12. In this embodiment, the ideal resonant frequency of the resonant network 12 is 6 MHz.

[0047] Step S21 specifically includes: adjusting the current input frequency in a first direction, and if the working current Ia increases, continuing to adjust until the working current Ia starts to decrease, so as to determine the maximum value of the working current Ia; if the working current Ia decreases, adjusting the current input frequency in a second direction opposite to the first direction, and if the working current Ia increases, continuing to adjust until the working current Ia starts to decrease, so as to determine the maximum value of the working current Ia; if the working current Ia still decreases, taking the initial working current Ia as the maximum value of the working current Ia. The first direction may be a direction in which the input frequency is gradually reduced, or a direction in which the input frequency is gradually increased.

[0048] refer to Figure 3Based on Example 1, in Example 2, after step S21, it also includes the following steps: S21a determines whether the maximum value of the working current Ia is within the preset current range. If so, the input frequency at the maximum value of the working current Ia is used as the optimal input frequency. If not, S23 outputs a fault signal. Wherein, it is also possible to return to restart and continue calibration while outputting the fault signal. If the number of failures exceeds the preset number or the entire calibration time exceeds the preset time, S24 outputs a fault signal and stops the operation of the resonant network 12. Wherein the preset current range is 2.5A-4.5A. Of course, other range values ​​can be selected as needed, and are not limited to the above data range. The preset current range is set around the ideal optimal working current. In this embodiment, the optimal working current is 3.6A. In theory, when the temperature of the metal induction part 20 does not enter the high temperature range or is calibrated from room temperature, then when the excitation source is the current duty cycle, the optimal working current corresponding to the ideal resonant frequency of the resonant network 12 is 3.6A, so the preset current range is set around the ideal optimal working current. The limits of the range are generally affected by the aging offset and manufacturing error of conventional capacitors and inductors. It is a maximum range value when heated to the longest time (preset time) of the calibration setting under the above conditions. It can be an estimated value or a set value obtained based on a large number of actual measurements. The preset number of times is 2 times, 3 times is greater than 2 times, etc., and the preset time is 1s or 2s.

[0049] Preferably, in the electromagnetic induction heating control method, the excitation source input frequency is calibrated according to an external control command, and / or the excitation source input frequency is calibrated each time the machine is turned on, and / or the excitation source input frequency is calibrated when the machine is turned on for the first time, and / or the excitation source input frequency is calibrated once after each preset number of turns on.

[0050] refer to Figure 4 , based on Example 1 and Example 2, in Example 3, the electromagnetic induction heating control method also includes step S3 to step S4.

[0051] S3, adjusting the duty cycle of the excitation source Fin to a second duty cycle, so as to rapidly heat the metal induction element 20. At this time, the excitation source Fin is input to the control terminal of the driving circuit 11 at the second duty cycle and the optimal input frequency, and the first duty cycle is smaller than the second duty cycle.

[0052] This step enables the heat-not-burn smoking device to heat the metal induction element 20 to heat the cigarette 200 continuously after calibration, thereby achieving calibration before use.

[0053] The electromagnetic induction heating control method further includes step S4.

[0054] S4, adjusting the duty cycle of the excitation source Fin so that the metal sensing element 20 is maintained at a preset temperature.

[0055] Step S4 specifically includes step S41 to step S44.

[0056] S41, finding the first current I1 at the inflection point of the first valley when the operating current Ia starts to change.

[0057] S42, obtaining a second current I2 at an inflection point of a second peak of the operating current Ia.

[0058] S43, determining a target current according to the values ​​of the first current I1 and the second current I2, wherein the target current is larger than the first current I1 and smaller than the second current.

[0059] S44, adjusting the duty cycle of the excitation source Fin according to the target current.

[0060] The main metal components of the metal induction element 20 are iron and nickel. The metal induction element 20 has a first Curie temperature T C1 and the second Curie temperature T of iron C2 Of course, the main metal of the metal induction component 20 is not limited to iron and nickel, and it can be multiple metal elements such as iron, nickel, chromium, manganese, cobalt, etc. The first two metal elements whose contents are greater than the preset range and can significantly affect the magnetic resistance Rm of the entire metal induction component 20 are selected as the main metal components, and the Curie temperatures of the two main metal components are taken as the first Curie temperature T C1 and the second Curie temperature T C2 .

[0061] The present invention controls the working temperature of the metal induction element 20 to be within the first Curie temperature T C1 and the second Curie temperature T C2 When temperature control is performed, the greater the working current Ia is, the higher the temperature is, and the smaller the magnetic resistance of the metal induction component 20 is.

[0062] In step S43, according to the preset first Curie temperature T C1 , preset second Curie temperature T C2 The first current I1 and the second current I2 are calculated at the first Curie temperature T of the metal induction element 20. C1 and the second Curie temperature T C2 The coefficient k and constant b of the temperature-current linear equation between , and the target temperature T of the metal induction member 20 is calculated according to the temperature-current linear equation. d Corresponding working current IaI d , the working current IaI d As the target current, the target temperature T d Greater than the first Curie temperature T C1and is less than the second Curie temperature T C2 .

[0063] Preferably, determining the target current according to the first current I1 and the second current I2 specifically includes: taking the weighted average of the first current value I1 and the second current I2 as the target current I d For example, the target current I d =eI1+fI2, e and f are constants, e+f=1, f is greater than or equal to 10% and less than or equal to 50%.

[0064] Of course, not limited to this, step S4 can directly use the relationship between the preset target temperature and the working current Ia to adjust the duty cycle, adjust the working current Ia to the target current, reduce the duty cycle of the excitation source Fin when the working current Ia is greater than the target current, and increase the duty cycle of the excitation source Fin when the working current Ia is less than the target current.

[0065] Preferably, in order to further improve the stability of the calibration of the input frequency of the excitation source, before step S1, that is, before calibration, the current temperature of the metal induction component is also detected and obtained (the current temperature can be determined by the current load resistance, or by the temperature sensor), and the input frequency of the excitation source Fin is calibrated when the current temperature does not exceed the preset temperature value, and the calibration is stopped and an over-temperature prompt is given when the current temperature exceeds the preset temperature value, and the preset temperature value can be selected as 80 degrees Celsius. Among them, since the temperature of the metal induction component affects the impedance size, the current temperature can be determined by the load resistance (the resistance of the metal induction component). Since the duty cycle is the preset first duty cycle at the start-up, the DC power supply is a DC power supply of a preset size, and the current working current is mainly affected by the excitation source frequency and the load resistance, and the input frequency of the excitation source will not deviate too far from the resonant frequency of the theoretical resonant network, so the working current can roughly reflect the temperature of the metal induction component at this time, so it can be determined whether the metal induction component exceeds the preset temperature by determining whether the range of the current working current exceeds the preset current range corresponding to the preset temperature, and if it exceeds, it is determined that the current temperature of the metal induction component exceeds the preset temperature value. This method can reduce the invalid calibration of the excitation source.

[0066] Preferably, when the temperature exceeds the preset temperature value, the calibration is stopped and an over-temperature prompt is given, and the calibration of the input frequency of the excitation source Fin can be skipped to proceed directly to the next step, for example, step S3: the excitation source Fin with the second duty cycle and the current input frequency (initial frequency) controls the resonant network 12 to start working to quickly heat the metal induction component 20.

[0067] Of course, temperature detection may not be performed before calibration. After obtaining the maximum operating current, the current maximum current range may be determined to determine whether the metal sensor is over-temperature or whether the driving circuit of the heat-not-burn smoking device has a frequency failure.

[0068] After obtaining the optimal input frequency, the control module 30 also records the optimal input frequency and uses the optimal input frequency as the initial frequency for the next startup and calibration. That is, step S22 also includes: recording the optimal input frequency and using the optimal input frequency as the initial frequency for the next startup and calibration.

[0069] Compared with the prior art, the present invention operates at a relatively low duty cycle and adjusts the frequency of the excitation source Fin before the heat-not-burn smoking device 100 starts working so that the operating frequency of the excitation source Fin is as close as possible to the resonant frequency of the resonant network 12, and adjusts the problem of the resonant frequency of the resonant network 12 deviating from the operating frequency of the excitation source Fin due to long-term use and errors in the components themselves, ensuring that the resonant network 12 operates in a resonant state, making the circuit close to a pure resistance working state, and having good heating stability.

[0070] Among them, when the heat-not-burn smoking device 100 of the present invention needs to be calibrated, after it is turned on, the duty cycle of the excitation source Fin changes to: the first duty cycle - the second duty cycle - the third duty cycle controlled by real-time feedback based on the target temperature of the metal sensing component, and the range of the third duty cycle floats according to needs, and is generally lower than the second duty cycle.

[0071] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A method for controlling electromagnetic induction heating of a heat-not-burn smoking device, the heat-not-burn smoking device comprising a driving circuit and a resonant network, the driving circuit converting a DC power supply into a high-frequency power supply signal according to an input excitation source to drive the resonant network to generate a high-frequency sine wave signal, and a metal induction element inducing the high-frequency sine wave signal to generate heat, characterized in that: The steps to calibrate the input frequency of the excitation source are as follows: Delivering an excitation source of an initial frequency to a driving circuit at a first duty cycle to start the resonant network working, wherein the first duty cycle is less than 50%; The working current of the resonant network is collected in real time, the input frequency of the excitation source is adjusted within a preset frequency range, the maximum working current is found, and the input frequency at the maximum working current is taken as the optimal input frequency, and the input frequency of the excitation source is adjusted to the optimal input frequency.

2. The electromagnetic induction heating control method according to claim 1, characterized in that: The first duty cycle is greater than or equal to 1% and less than or equal to 15%.

3. The electromagnetic induction heating control method according to claim 1, characterized in that: The excitation source input frequency is calibrated according to an external control command, and / or the excitation source input frequency is calibrated each time the machine is turned on, and / or the excitation source input frequency is calibrated when the machine is turned on for the first time, and / or the excitation source input frequency is calibrated once after each preset number of turns on.

4. The electromagnetic induction heating control method according to claim 1, characterized in that: After obtaining the optimal input frequency, the optimal input frequency is also recorded, and the optimal input frequency is used as the initial frequency of the excitation source during the next startup and calibration.

5. The electromagnetic induction heating control method according to claim 1, characterized in that: The preset frequency range is 5 MHz-7 MHz.

6. The electromagnetic induction heating control method according to claim 1, characterized in that: When the maximum value of the working current is found, it is also determined whether the maximum value of the working current is within a preset current range. If so, the input frequency at the maximum value of the working current is used as the optimal input frequency. If not, a fault signal is output and / or the input frequency of the excitation source is recalibrated until the optimal input frequency is within the preset current range or the calibration times exceed the preset times, a fault signal is output and the power supply of the resonant network is shut down; and / or, Before calibrating the input frequency of the excitation source, the current temperature of the metal induction component is also detected and acquired. When the current temperature does not exceed the preset temperature value, the input frequency of the excitation source is calibrated, and when the current temperature exceeds the preset temperature value, the calibration is stopped.

7. The electromagnetic induction heating control method according to claim 6, characterized in that: The preset current range is 2.5A-4.5A.

8. The electromagnetic induction heating control method according to claim 1, characterized in that: The input frequency of the excitation source is adjusted within a preset frequency range, and the steps for finding the maximum value of the working current are as follows: adjusting the current input frequency in a first direction, and if the working current increases, continuing to adjust until the working current begins to decrease, so as to determine the maximum value of the working current; if the working current decreases, adjusting the current input frequency in a second direction opposite to the first direction, and if the working current increases, continuing to adjust until the working current begins to decrease, so as to determine the maximum value of the working current; if the working current still decreases, taking the initial working current as the maximum value of the working current.

9. The electromagnetic induction heating control method according to claim 1, characterized in that: After calibrating the input frequency of the excitation source, the method further includes the step of adjusting the duty cycle of the excitation source to a second duty cycle so that the metal induction component is quickly heated, wherein the first duty cycle is smaller than the second duty cycle.

10. The electromagnetic induction heating control method according to claim 9, characterized in that: The second duty cycle is greater than or equal to 90% and less than or equal to 98%.

11. The electromagnetic induction heating control method according to claim 9, characterized in that: After adjusting the duty cycle of the excitation source to the second duty cycle, the method further comprises the steps of: The duty cycle of the excitation source is adjusted to maintain the metal induction element at a target temperature.

12. The electromagnetic induction heating control method according to claim 11, characterized in that: Adjusting the duty cycle of the excitation source so that the metal sensing element is maintained at a target temperature specifically includes: After adjusting the duty cycle of the excitation source to the second PWM duty cycle, find the first current I1 at the inflection point of the first trough of the current change, and obtain the second current I2 at the inflection point of the second peak of the current change; determine the target current according to the numerical values ​​of the first current I1 and the second current I2, the target current is greater than the first current I1 and less than the second current I2; adjust the duty cycle of the excitation source according to the target current.

13. An electromagnetic induction heating control device for a heat-not-burn smoking device, characterized in that: include: A current collection circuit, used for collecting the working current of the electromagnetic generating device; one or more processors; Memory; as well as One or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by one or more processors to implement the electromagnetic induction heating control method for the heat-not-burn smoking article as claimed in any one of claims 1 to 12.

14. A heat-not-burn tobacco device, comprising a power supply, a drive circuit, a resonant network and a control module, wherein the power supply outputs a DC power supply, the control module controls the duty cycle of an excitation source of the drive circuit, the drive circuit converts the DC power supply into an AC power signal according to the excitation source, the resonant network generates a high-frequency electromagnetic wave according to the power signal, and a metal induction element induces the high-frequency electromagnetic wave to generate heat to heat a cigarette, characterized in that: The control module includes the electromagnetic induction heating control device for the heat-not-burn smoking article as claimed in claim 13.

15. A heat-not-burn tobacco device, comprising a power supply, a drive circuit, a resonant network and a control module, wherein the power supply outputs a DC power supply, the control module controls the duty cycle of an excitation source of the drive circuit, the drive circuit converts the DC power supply into an AC power signal according to the excitation source, the resonant network generates a high-frequency electromagnetic wave according to the power signal, and a metal induction element induces the high-frequency electromagnetic wave to generate heat to heat a cigarette, characterized in that: The control module includes an acquisition circuit and a control unit. The acquisition circuit acquires the working current of the resonant network. The control unit transmits an excitation source of an initial frequency to the driving circuit at a first duty cycle to enable the resonant network to start working, adjusts the input frequency of the excitation source within a preset frequency range, searches for the maximum value of the working current, and uses the input frequency at the maximum value of the working current as the optimal input frequency, and adjusts the input frequency of the excitation source to the optimal input frequency.

Images