Method and circuit for determining consistency of equivalent impedance of heating component

Abstract

The invention discloses a method and circuit for determining consistency of equivalent impedance of a heating component, and the method comprises the steps: respectively determining a detection voltage value of a detection coil under the condition that a to-be-detected heating component is placed and a standard voltage value of the detection coil under the condition that a standard heating component is placed in a same alternating magnetic field, the background voltage value of the coil under the condition that the heating part is not placed is detected; determining a standard voltage change rate corresponding to the standard heating component based on the standard voltage value and the background voltage value; determining a detection voltage change rate corresponding to the heating component to be detected based on the detection voltage value and the background voltage value; based on the detection voltage change rate and the standard voltage change rate, determining the voltage sensitivity corresponding to the heating component to be detected; determining whether the absolute value of the voltage sensitivity is less than or equal to a preset threshold; and if yes, determining that the equivalent impedance of the to-be-tested heating component is consistent with that of the standard heating component. Therefore, a detection method is provided for the electromagnetic induction performance of the electromagnetic induction type aerosol generation system.

Description

Technical Field

[0001] The present invention relates to the field of new tobacco, and particularly to a method and circuit for determining the consistency of the equivalent impedance of a heating component. Background Art

[0002] The electromagnetic induction type heat-not-burn cigarette belongs to a new type of tobacco product, which heats tobacco by using electromagnetic induction heating technology to replace the traditional combustion method. The core technology of this new type of tobacco product lies in its heating mechanism. Through the principle of electromagnetic induction, the temperature is precisely controlled, and the tobacco is evenly heated, so that the tobacco releases the required flavor and nicotine at a lower temperature. This design helps to reduce the harmful substances released by tobacco combustion, reduce the potential risk to the health of users, also reduce the pollution of second-hand smoke to the surrounding environment, and at the same time can provide a similar usage experience to traditional cigarettes.

[0003] For the electromagnetic induction type heat-not-burn cigarette, the electromagnetic induction characteristics of the heating component are one of the key performances of this product. However, the current detection methods for such products still focus on battery performance and circuit port characteristics, and the detection methods for their electromagnetic induction performance are not yet perfect, and there are still certain gaps in the detection index system. Therefore, it is necessary to improve the existing detection methods for new tobacco products to make them more suitable for new tobacco products containing electromagnetic induction heating components. Summary of the Invention

[0004] In a first aspect, an embodiment of the present application provides a method for determining the consistency of the equivalent impedance of a heating component, where the heating component is used for an electromagnetic induction type aerosol generating system, including:

[0005] Determine the detected voltage value of the detection coil with the heating component to be tested placed therein, the standard voltage value of the detection coil with the standard heating component placed therein, and the background voltage value of the detection coil without any heating component placed therein in the same alternating magnetic field;

[0006] Based on the standard voltage value and the background voltage value, determine the standard voltage change rate corresponding to the standard heating component;

[0007] Based on the detected voltage value and the background voltage value, determine the detected voltage change rate corresponding to the heating component to be tested;

[0008] Based on the detected voltage change rate and the standard voltage change rate, determine the voltage sensitivity corresponding to the heating component to be tested, where the voltage sensitivity is used to indicate the difference in the electromagnetic induction performance between the heating component to be tested and the standard heating component;

[0009] Determine whether the absolute value of the voltage sensitivity is less than or equal to a preset threshold;

[0010] When the absolute value of the voltage sensitivity is less than or equal to a preset threshold, it is determined that the equivalent impedance of the heating component to be measured is consistent with that of the standard heating component.

[0011] In some embodiments, the step of determining the voltage sensitivity corresponding to the heating component to be measured based on the detected voltage change rate and the standard voltage change rate includes:

[0012] Based on the detected voltage change rate and the standard voltage change rate, determine the change rate difference between the absolute value of the detected voltage change rate and the absolute value of the standard voltage change rate;

[0013] Based on the ratio of the change rate difference to the absolute value of the standard voltage change rate, determine the voltage sensitivity corresponding to the heating component to be measured.

[0014] In some embodiments, the step of determining the standard voltage change rate corresponding to the standard heating component based on the standard voltage value and the background voltage value includes:

[0015] Based on the standard voltage value and the background voltage value, determine the first voltage difference between the absolute value of the standard voltage value and the absolute value of the background voltage value;

[0016] Based on the ratio of the first voltage difference to the absolute value of the standard voltage value, determine the standard voltage change rate corresponding to the standard heating component.

[0017] In some embodiments, the step of determining the detected voltage change rate corresponding to the heating component to be measured based on the detected voltage value and the background voltage value includes:

[0018] Based on the detected voltage value and the background voltage value, determine the second voltage difference between the absolute value of the detected voltage value and the absolute value of the background voltage value;

[0019] Based on the ratio of the second voltage difference to the absolute value of the standard voltage value, determine the detected voltage change rate corresponding to the heating component to be measured.

[0020] In some embodiments, it further includes:

[0021] When the voltage sensitivity is greater than the preset threshold, it is determined that the equivalent impedance of the heating component to be measured is not consistent with that of the standard heating component.

[0022] In some embodiments, the preset threshold is 1% - 3%.

[0023] In a second aspect, an embodiment of the present application provides a circuit for determining the consistency of the equivalent impedance of a heating component, including:

[0024] A resonant amplification circuit is used to determine the voltage amplification signal of a detection coil. The resonant amplification circuit includes a first inductor, a first resistor, and a first capacitor. Among them, the first inductor and the first resistor come from the connected detection coil;

[0025] A signal conditioning module is used to condition the voltage amplification signal from the resonant amplification circuit into a weak electrical signal;

[0026] A processor is used to process the weak electrical signal from the signal conditioning module and execute the method of any one of the embodiments in the first aspect.

[0027] In some embodiments, the resonant amplification circuit includes a series resonant amplification circuit. The series resonant amplification circuit includes an AC voltage, a first inductor, a first resistor, a first capacitor, a second resistor, and an amplification element. Among them, one end of the second resistor is connected to the AC voltage, and the other end of the second resistor is connected to the inverting input terminal of the amplification element and one end of the detection coil. The other end of the detection coil is connected to the output terminal of the amplification element through the first capacitor, and the non-inverting input terminal of the amplification element is grounded.

[0028] In some embodiments, the resonant amplification circuit includes a parallel resonant amplification circuit. The parallel resonant amplification circuit includes an AC voltage, a first inductor, a first resistor, a first capacitor, a second resistor, an amplification element, and a feedback resistor. Among them, the detection coil, the first capacitor, and the feedback resistor are connected in parallel. One end of the second resistor is connected to the AC voltage, and the other end of the second resistor is connected to the inverting input terminal of the amplification element, one end of the feedback resistor, one end of the first capacitor, and one end of the detection coil. The other end of the detection coil is connected to the output terminal of the amplification element, and the non-inverting input terminal of the amplification element is grounded.

[0029] In some embodiments, the resonant amplification circuit further includes a diode, a third resistor, and a second capacitor. Among them, the third resistor is connected in parallel with the second capacitor. The negative electrode of the diode is connected to the output terminal of the amplification element, and the positive electrode of the diode is connected to one end of the third resistor and one end of the second capacitor. The other ends of the third resistor and the second capacitor are respectively grounded; and / or, the AC voltage is provided by an AC voltage source chip. Description of the Drawings

[0030] Figure 1 A flowchart showing a method for determining the consistency of the equivalent impedance of a heating component according to some embodiments of the present application;

[0031] Figure 2 A flowchart showing a method for determining the voltage sensitivity corresponding to a heating component to be measured according to some embodiments of the present application;

[0032] Figure 3 A flowchart showing a method for determining the standard voltage change rate corresponding to a standard heating component according to some embodiments of the present application;

[0033] Figure 4 A flowchart showing the determination of the rate of change of the detection voltage corresponding to a heating component to be measured according to some embodiments of the present application;

[0034] Figure 5 A schematic circuit diagram showing the determination of the consistency of the equivalent impedance of a heating component according to some embodiments of the present application;

[0035] Figure 6 A series resonance amplification circuit diagram showing according to some embodiments of the present application;

[0036] Figure 7 A parallel resonance amplification circuit diagram showing according to some embodiments of the present application;

[0037] Figure 8 A mutual inductance coupling model of a detection coil and a heating component showing according to some embodiments of the present application;

[0038] Figure 9a A planar spiral detection coil showing according to some embodiments of the present application;

[0039] Figure 9b A planar rectangular detection coil showing according to some embodiments of the present application;

[0040] Figure 9c A cylindrical solenoid detection coil showing according to some embodiments of the present application;

[0041] Figure 9d A short dipole pair spiral detection coil showing according to some embodiments of the present application. Detailed implementation manners

[0042] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention will be introduced in conjunction with preferred embodiments, this does not mean that the features of this invention are limited to this implementation manner. On the contrary, the purpose of introducing the invention in conjunction with the implementation manner is to cover other alternatives or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, many specific details will be included in the following description. The present invention can also be implemented without using these details. In addition, in order to avoid confusing or obscuring the key points of the present invention, some specific details will be omitted in the description. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0043] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0044] In the description of this embodiment, it should also be noted that unless otherwise clearly specified and defined, the terms "arranged", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this embodiment can be understood according to specific situations.

[0045] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the drawings.

[0046] In a first aspect, referring to Figure 1 , the present application provides a method for determining the consistency of the equivalent impedance of a heating component, where the heating component is used in an electromagnetic induction type aerosol generating system. The method includes the following steps:

[0047] Step S11, respectively determine the detected voltage value U eq_exam of the detection coil when placing the heating component to be detected in the same alternating magnetic field, and the standard voltage value U eq_std of the detection coil when placing the standard heating component, and the background voltage value U D of the detection coil when no heating component is placed;

[0048] Step S12, based on the standard voltage value U eq_std and the background voltage value U D , determine the standard voltage change rate δ std corresponding to the standard heating component;

[0049] Step S13, based on the detected voltage value and the background voltage value, determine the detected voltage change rate δ exam corresponding to the heating component to be detected;

[0050] Step S14, based on the detected voltage change rate δ exam and the standard voltage change rate δ std , determine the voltage sensitivity S corresponding to the heating component to be detected. Among them, the voltage sensitivity S is used to indicate the difference in the electromagnetic induction performance between the heating component to be detected and the standard heating component;

[0051] Step S15, determine whether the absolute value of the voltage sensitivity S is less than or equal to a preset threshold;

[0052] When the absolute value of the voltage sensitivity S is less than or equal to the preset threshold, step S16 is executed to determine whether the equivalent impedance of the heating component to be tested is consistent with that of the standard heating component.

[0053] It should be noted that "heating components" can be understood as components that heat tobacco substrates or other atomizable materials by rapidly heating up through eddy currents in electromagnetic induction aerosol generating systems; "standard heating components" can be understood as heating components that, under the conditions of a given heating coil, heating power and heating frequency, have consistent induced eddy currents, bring about consistent temperature rise effects, and meet the design requirements of the aerosol generating system. "Consistency of equivalent impedance of heating components" can be understood as the temperature rise of heating components of the same batch or different batches in the same time is consistent or nearly consistent, giving users the same or slightly different puffing experience, thereby avoiding inconsistent puffing experience due to inconsistent equivalent impedance of heating components.

[0054] The "electromagnetic induction aerosol generating system" can be a smoking device induction heating product, that is, the heating component is fixed to the aerosol generating device; it can also be a cigarette induction heating product, that is, the heating component is located in the aerosol generating product. The aerosol generating product can be a smoking product in the shape of a cigarette, including but not limited to tobacco flakes, tobacco particles, tobacco shreds, reconstituted tobacco and other tobacco products that can be heated by an aerosol generating device to produce an aerosol for the user to inhale.

[0055] In some embodiments, the detection voltage value U eq_exam , standard voltage value U eq_std and background voltage value U D It can be a voltage amplitude; in other embodiments, the detection voltage value U eq_exam , standard voltage value U eq_std and background voltage value U D It can also be the effective value of voltage.

[0056] According to the method for determining the consistency of the equivalent impedance of the heating component of the present application, the heating component and the detection coil are taken as a whole, and the impedance change of the whole is converted into a voltage change. The voltage sensitivity S corresponding to the heating component to be tested is calculated and its absolute value is compared with a preset threshold value, so as to determine the consistency of the equivalent impedance of the heating component, thereby providing a detection method for the electromagnetic induction performance of the electromagnetic induction aerosol generating system; in addition, the present application calculates the voltage sensitivity S of the heating component to be tested based on the voltage change rates corresponding to the heating component to be tested and the standard heating component, respectively, rather than directly based on the voltage difference, so that smaller voltage changes can be amplified, thereby improving the accuracy of the voltage sensitivity.

[0057] In some embodiments, reference Figure 2, step S14, based on the detection voltage change rate δ exam and the standard voltage change rate δ std , determine the voltage sensitivity S corresponding to the heating component to be measured, which may include the following steps:

[0058] Step S141, based on the detection voltage change rate δ exam and the standard voltage change rate δ std , determine the change rate difference between the absolute value of the detection voltage change rate and the absolute value of the standard voltage change rate.

[0059] Step S142, based on the ratio of the change rate difference to the absolute value of the standard voltage change rate δ std , determine the voltage sensitivity S corresponding to the heating component to be measured.

[0060] In other words, the voltage sensitivity S can be expressed as

[0061]

[0062] In formula (1), S represents the voltage sensitivity corresponding to the heating component to be measured; δ exam represents the detection voltage change rate; δ std represents the standard voltage change rate.

[0063] In some embodiments, referring to Figure 3 , step S12, based on the standard voltage value U eq_std and the background voltage value U D , determine the standard voltage change rate δ std corresponding to the standard heating component, which may include the following steps:

[0064] Step S121, based on the standard voltage value U eq_std and the background voltage value U D , determine the first voltage difference between the absolute value of the standard voltage value and the absolute value of the background voltage value.

[0065] Step S122, based on the ratio of the first voltage difference to the absolute value of the standard voltage value U eq_std , determine the standard voltage change rate δ std corresponding to the standard heating component.

[0066] In other words, the standard voltage change rate δ std can be expressed as

[0067]

[0068] In formula (2), δ std represents the standard voltage change rate; U eq_std represents the standard voltage value; U DRepresents the background voltage value.

[0069] In some embodiments, referring to Figure 4 , step S13, based on the detected voltage value U eq_exam and the background voltage value U D , determining the detection voltage change rate δ exam corresponding to the heating component to be measured may include the following steps:

[0070] Step S131, based on the detected voltage value U eq_exam and the background voltage value U D , determining the second voltage difference between the absolute value of the detected voltage value and the absolute value of the background voltage value.

[0071] Step S132, based on the ratio of the second voltage difference to the absolute value of the standard voltage value U eq_std , determining the detection voltage change rate δ exam corresponding to the heating component to be measured.

[0072] In other words, the detection voltage change rate δ exam can be expressed as

[0073]

[0074] In formula (3), δ exam represents the detection voltage change rate; U eq_exam represents the detected voltage value; U D represents the background voltage value.

[0075] According to formulas (1) to (3), the voltage sensitivity S can also be expressed as

[0076]

[0077] In formula (4), S represents the voltage sensitivity corresponding to the heating component to be measured; U eq_exam represents the detected voltage value; U eq_std represents the standard voltage value; U D represents the background voltage value.

[0078] It can be seen from formula (4) that in this application, the difference between the detected voltage value U eq_exam and the standard voltage value U eq_std is used to represent the difference in electromagnetic induction performance between the heating component to be measured and the standard heating component. The smaller the voltage sensitivity S, the smaller the difference between the heating component to be measured and the standard heating component, that is, the better the consistency; when the voltage sensitivity S = 0, that is, the heating component to be measured is the standard heating component.

[0079] In some embodiments, referring to Figure 1 , the method further includes the following steps:

[0080] When the voltage sensitivity is greater than a preset threshold, step S17 is executed to determine that the equivalent impedance of the heating component to be measured is not consistent with that of the standard heating component. In other words, the temperature rise of the heating component to be measured and the standard heating component is inconsistent within the same time, resulting in different user suction experiences.

[0081] In some embodiments, the preset threshold ε can be 1% - 3%. This preset threshold ε can also be understood as the maximum allowable error between the electromagnetic induction performance of the heating component to be detected and that of the standard heating component. When the difference in voltage sensitivity between the heating component to be measured and the standard heating component is within the range of this preset threshold ε, it can be determined that the heating component to be measured is qualified, that is, its equivalent impedance is consistent with that of the standard heating component, satisfying

[0082] S≤ε (5)

[0083] In formula (5), S represents the voltage sensitivity corresponding to the heating component to be measured; ε represents the preset threshold.

[0084] In a second aspect, referring to Figure 5 , the present application further provides a circuit for determining the consistency of the equivalent impedance of a heating component, including: a resonance amplification circuit 10, a signal conditioning module 20, and a processor 30. Among them, the resonance amplification circuit 10 is used to determine the voltage amplification signal of the detection coil. Combining Figure 6 and Figure 7 , the resonance amplification circuit includes a first inductor L D , a first resistor R D , and a first capacitor C. The first inductor L D and the first resistor R D come from the connected detection coil. In other words, after the detection coil is connected, it can be equivalent to the first inductor L D and the first resistor R D , and form a resonance circuit with the first capacitor C. Exemplarily, the detection coil can be connected to the circuit through the wiring ports at both ends thereof, and the voltage at both ends of the detection coil can be connected to a measuring instrument of an oscilloscope through a voltage probe to obtain a voltage amplification signal for subsequent processing by the signal adjustment module 20. The voltage amplification signal can include the detection voltage signal corresponding to the detection voltage value U eq_exam in the above-mentioned first aspect method, the standard voltage signal corresponding to the standard voltage value U eq_std , and the background voltage signal corresponding to the background voltage value U D .

[0085] The signal conditioning module 20 is used to condition the voltage amplification signal from the resonant amplification circuit 10 into a weak electrical signal. The weak electrical signal can be amplified, filtered, and shaped more precisely, thereby improving the sensitivity of the entire system. Secondly, the weak electrical signal is less sensitive to external interference (such as electromagnetic interference), so it is less interfered with during transmission, which helps to maintain the integrity of the signal.

[0086] The processor 30 is used to process the weak electrical signal from the signal conditioning module 20 and execute the method of any one of the embodiments in the first aspect above, which will not be elaborated here.

[0087] The circuit for determining the consistency of the equivalent impedance of the heating component according to the present application, which is based on the resonant topology amplification circuit, amplifies the relatively small voltage signal of the detection coil, and then conditions the amplified voltage signal into a weak electrical signal through the signal conditioning module 20 for processing by the processor 30, thereby improving the accuracy of the calculation result.

[0088] In some embodiments, the processor 30 can be a microcontroller. Specifically, the processor 30 can adopt a microcontroller with the model number STM32F030C8T6. It is a microcontroller based on the ARM Cortex-M0 core produced by STMicroelectronics, with advantages such as high cost performance, low power consumption, and rich peripherals.

[0089] In some embodiments, refer to Figure 6 , the resonant amplification circuit includes a series resonant amplification circuit, and the series resonant amplification circuit includes an AC voltage U AC , a first inductor L D , a first resistor R D , a first capacitor C, a second resistor R 2 and an amplification element A. Among them, one end of the second resistor R 2 is connected to the AC voltage U AC , the other end of the second resistor R 2 is connected to the inverting input terminal of the amplification element A and one end of the detection coil, the other end of the detection coil is connected to the output terminal of the amplification element A through the first capacitor C, and the non-inverting input terminal of the amplification element A is grounded. Exemplarily, the amplification element A can be an amplifier (such as an operational amplifier).

[0090] In some embodiments, refer to Figure 7 , the resonant amplification circuit includes a parallel amplification resonant circuit, and the parallel resonant amplification circuit includes an AC voltage U AC , a first inductor L D , a first resistor R D , a first capacitor C, a second resistor R 2 , an amplification element A and a feedback resistor R f. Among them, the detection coil, the first capacitor C, and the feedback resistor R f are connected in parallel with each other. One end of the second resistor R 2 is connected to the AC voltage U AC . The other end of the second resistor R 2 is connected to the inverting input terminal of the amplifying element A, one end of the feedback resistor R f , one end of the first capacitor C, and one end of the detection coil. The other end of the detection coil is connected to the output terminal of the amplifying element A, and the non-inverting input terminal of the amplifying element A is grounded. Exemplarily, the amplifying element A can be an amplifier (such as an operational amplifier). By setting the feedback resistor R f , a part of the output signal of the amplifier is fed back to the inverting input terminal of the amplifier to establish a negative feedback loop inside the amplifier, so as to be able to stabilize the gain of the amplifier, prevent the amplifier from working in the saturation or non-linear region, and improve the working stability of the circuit.

[0091] In some embodiments, referring to Figure 6 and Figure 7 , the resonant amplification circuit further includes a diode D e , a third resistor R e , and a second capacitor C e . Among them, the negative electrode of the diode D e is connected to the output terminal of the amplifying element A, and the positive electrode of the diode D e is connected to one end of the third resistor R e and one end of the second capacitor C e . The third resistor R e is in parallel with the second capacitor C e . The other end of the third resistor R e and the other end of the second capacitor C e are respectively grounded. Since the diode D e has a one-way conduction function, it can prevent the signal from being transmitted in the reverse direction and avoid interfering with the amplifier and subsequent circuits. Secondly, by the parallel connection of the third resistor R e and the second capacitor C e , it can ensure that the amplifier can operate normally and stably.

[0092] The above two resonant amplification circuits (such as the series resonant amplification circuit shown in Figure 6 and the parallel resonant amplification circuit shown in Figure 7 ) can both judge the consistency of the equivalent impedance of the heating component through the change of the voltage amplification signal. The difference is that when the circuit adjusts the resonant working condition, the total impedance of the series resonant amplification circuit reaches the minimum value at the resonant frequency, so the current passing through the loop reaches the maximum value at resonance; the total impedance of the parallel resonant amplification circuit reaches the maximum value at the resonant frequency, so the current passing through the loop reaches the minimum value at resonance.

[0093] For a series resonance amplification circuit, its sensitivity to impedance changes is relatively high, and it can effectively reflect the small impedance differences of heating components. Therefore, it is more suitable for the precision detection of heating components with high performance requirements. If higher detection accuracy is required (such as the judgment of small differences), preferably, a series resonance amplification circuit is adopted.

[0094] For a parallel resonance amplification circuit, its response to the signal amplitude is more stable, and its anti-interference performance is stronger. It is suitable for batch detection and complex detection environments. If the detection environment is relatively complex (such as large interference signals), preferably, a parallel resonance amplification circuit is adopted.

[0095] It should be noted that although only the embodiments of the series resonance amplification circuit and the parallel resonance amplification circuit are shown in this application, those skilled in the art can understand that other composite resonance circuits can also be adopted in this application to achieve the purpose.

[0096] In some embodiments, the AC voltage is provided by an AC voltage source chip. Specifically, the AC voltage source chip can be a chip with the model number AD9851BRSZRL. It is a direct digital frequency synthesizer (DDS) chip produced by Analog Devices, Inc. (ADI for short). It has powerful functions and high integration, and can generate high-precision sine wave signals.

[0097] In order to improve the accuracy of voltage sensitivity, the inventor further studies the influencing factors of voltage sensitivity based on the mutual inductance coupling model.

[0098] The mutual inductance coupling model between the detection coil and the heating component is as Figure 8 shown. According to Faraday's law of electromagnetic induction, when a bulk conductor is placed in an alternating magnetic field or moves in a fixed magnetic field, an induced current is generated in the conductor and closes within the conductor. Therefore, the heating component under the eddy current effect can be equivalent to a short-circuit loop current model, and at this time, the heating component can be equivalent to a coil. As Figure 8 shown, L D represents the self-inductance of the detection coil, R D represents the internal resistance of the detection coil, I D represents the current flowing through the detection coil; L H represents the self-inductance of the heating component, R H represents the internal resistance of the heating component, I H represents the current flowing through the heating component; M represents the mutual inductance between the heating component and the detection coil.

[0099] The induced electromotive force V mD on the detection coil can be expressed as:

[0100] VmD = jωMI H (6)

[0101] In formula (6), V mD represents the induced electromotive force on the detection coil; j represents the imaginary unit; ω represents the angular frequency of the alternating voltage; M represents the mutual inductance between the heating component and the detection coil; I H represents the current flowing through the heating component.

[0102] The total voltage V D on the detection coil can be expressed as:

[0103] V D = Z D I D + V mD = Z D I D + jωMI H (7)

[0104] In formula (7), V D represents the total voltage on the detection coil; Z D represents the impedance of the detection coil when no detection coil is placed; I D represents the current flowing through the detection coil; V mD represents the induced electromotive force on the detection coil; j represents the imaginary unit; ω represents the angular frequency of the alternating voltage; M represents the mutual inductance between the heating component and the detection coil; I H represents the current flowing through the heating component.

[0105] The induced electromotive force V mH on the heating component can be expressed as:

[0106] V mH = jωMI D (8)

[0107] In formula (8), V mH represents the induced electromotive force on the heating component; j represents the imaginary unit; M represents the mutual inductance between the heating component and the detection coil; I D represents the current flowing through the detection coil.

[0108] The total voltage V H on the heating component can be expressed as:

[0109] V H = Z H I M + V mH = Z H I M + jωMI D (9)

[0110] Formula (9), V H represents the total voltage across the heating component; Z H represents the impedance of the heating component; I H represents the current flowing through the heating component; V mH represents the induced electromotive force across the heating component; j represents the imaginary unit; ω represents the angular frequency of the alternating voltage; M represents the mutual inductance between the heating component and the detection coil; I D represents the current flowing through the detection coil.

[0111] Since the heating component is equivalent to a short - circuit loop current model, the total voltage V across the heating component H = 0, that is, Formula (9) can be expressed as:

[0112] V H = Z H I H +jωMI D = 0,

[0113] Solving for I H , that is

[0114]

[0115] Substituting Formula (10) into Formula (7), we get:

[0116]

[0117] After simplification, we get:

[0118]

[0119] Dividing Formula (11) by ID, we can obtain the equivalent impedance Z eq of the detection coil:

[0120]

[0121] Z D = R D +jωL D (13)

[0122] After substituting Formula (13) into Formula (12) and separating the real and imaginary parts, we get:

[0123]

[0124] Among them, the real - part coefficient is also the change - ratio coefficient of the internal resistance of the detection coil The imaginary - part coefficient is also the change - ratio coefficient of the self - inductance of the detection coil

[0125] Reference Figure 6 andFigure 7 , due to the virtual short - circuit and virtual open - circuit characteristics of the amplifier, when the alternating voltage U AC is constant, the magnitude of the current flowing through the detection coil is the same when the heating component is not placed (i.e., before placing the heating component) and when the heating component is placed (i.e., after placing the heating component). Therefore, the voltage change of the detection coil before and after placing the heating component is equal to its impedance change, that is, the impedance change rate of the detection coil is equal to the voltage change rate δ, which can be expressed as,

[0126]

[0127] where,

[0128] In formula (14), δ represents the impedance change rate (or voltage change rate) of the detection coil; Z eq represents the equivalent impedance of the detection coil when the heating component is placed; Z D represents the impedance of the detection coil when the heating component is not placed; Q D is the equivalent quality factor of the detection coil; β represents the proportion coefficient of the internal resistance change of the detection coil; α represents the proportion coefficient of the self - inductance change of the detection coil.

[0129] It can be seen that the impedance change rate (or voltage change rate) δ of the detection coil is related to the mutual inductance M of the heating body to the detection coil. Therefore, by increasing the mutual inductance M, the impedance change rate (or voltage change rate) δ of the detection coil can be increased.

[0130] Referring to formula (1), the voltage sensitivity In other words, by increasing the mutual inductance M, the impedance change rate (or voltage change rate) δ of the detection coil can be increased, and thus the accuracy of the voltage sensitivity S can be improved.

[0131] The inventor also found that by designing a reasonable structure and size of the detection coil, the mutual inductance M can be increased. That is to say, according to the different structures of the heating component to be measured, the mutual inductance M can be increased by designing the corresponding detection coil, and thus the detection accuracy can be improved.

[0132] According to the law of electromagnetic induction, the induced current in the heating component is proportional to the intensity of the induced magnetic field generated by the detection coil and its component perpendicular to the surface of the heating component. It can be seen that increasing the intensity of the induced magnetic field and its perpendicular component is the key factor in enhancing the mutual inductance M. Therefore, the detection coil can be optimized and designed from the following aspects, including but not limited to: (1) The detection coil is designed with a multi-turn spiral structure to enhance the intensity of the induced magnetic field. The number of turns and layers of the coil can be adjusted according to the detection accuracy requirements, but it needs to be designed in combination with the frequency and inductance value to avoid too low resonance frequency; (2) The plane (cross-section) of the detection coil should be as parallel as possible to the plane of the heating component (i.e., the plane with the largest cross-sectional area), and the distance should be kept within a small range to increase the perpendicular component of the magnetic field; (3) The design of the detection coil should ensure that its central position is aligned with the center of the heating component, so as to optimize the distribution of the perpendicular component of the magnetic field; (4) The diameter of the detection coil should match the size of the heating component to ensure that the induced magnetic field can completely cover the surface of the heating component; (5) In the design of a multi-layer spiral detection coil, the distance between layers should be minimized to improve the uniformity and coupling strength of the magnetic field.

[0133] Figures 9a to 9d The structural diagram of the detection coil provided by some embodiments of the present application is shown. The following combines Figures 9a to 9d to specifically illustrate that according to the different structures of the heating component to be measured, the mutual inductance M can be enhanced by designing the corresponding detection coil, thereby improving the detection accuracy.

[0134] For flat, thin-film or large-area heating components to be measured, a planar spiral detection coil as shown in Figure 9a can be used ( Figure 9a The difference between the left and right figures in is the number of turns of the coil, and the structure is a planar spiral type). The planar spiral coil can generate a uniform induced magnetic field in the planar area, and its perpendicular component is the largest, which is suitable for covering a large planar area.

[0135] For long, rectangular cross-section heating components to be measured, a planar rectangular detection coil as shown in Figure 9b can be used. The induced magnetic field of the planar rectangular coil is mainly concentrated in the long strip area, which is suitable for matching with strip-shaped heating components.

[0136] For columnar, annular or axisymmetric structure heating components, a cylindrical solenoid detection coil as shown in Figure 9c can be used. The axial magnetic field intensity of the cylindrical solenoid coil is the largest, so it is suitable for surrounding the columnar heating body to generate an induced magnetic field with a strong perpendicular component.

[0137] For dispersed, locally characterized or small heating components to be measured (such as locally asymmetric heating components, heating components with complex geometric structures), a Figure 9dThe short dipole pair spiral detection coil shown. The short dipole pair spiral coil can generate a local strong magnetic field, so its distribution is suitable for heating bodies with small and complex geometries, especially for local detection.

[0138] Table 1 shows an example of the parameter design of a planar spiral detection coil (as shown in Figure 9a ), in a series resonance amplification circuit (as shown in Figure 6 ).

[0139] Table 1 shows an example of the parameter design of a planar spiral detection coil (as shown in Figure 9a ), in a series resonance amplification circuit (as shown in Figure 6 ).

[0140] Parameter Value <![CDATA[Self-inductance L of the detection coil when the heating component to be measured is not placed D > 10 μH <![CDATA[Detect the internal resistance R of the detection coil when the heating component to be tested is not placed D > 3 Ω AC excitation source frequency f 3 MHz

[0141] It should be noted that the parameters of the detection coil, such as the self-inductance L D and the internal resistance R D , can be determined by a method combining theoretical calculation, simulation analysis and experimental measurement. Specifically, using the geometric dimensions and material properties of the detection coil, its self-inductance value L D is accurately calculated through electromagnetic simulation software; at the same time, combined with the simulation analysis of the material resistivity of the wire and the high-frequency skin effect, the internal resistance R D is measured. In addition, the actual electrical parameters of the detection coil are also verified by experimental measurement using an impedance analyzer or an LCR meter, so as to ensure the accuracy of the values in Table 1.

[0142] The frequency f of the alternating voltage (alternating current excitation source) U AC can be determined by the following principles: one is to ensure that the excitation frequency matches the operating frequency range of the detection coil and the electromagnetic characteristics of the heating component to be measured; the other is to avoid electromagnetic interference and excessive circuit losses caused by too high a frequency while improving the detection sensitivity.

[0143] The first capacitor C can be determined by resonance matching according to the frequency f of the alternating current excitation source U AC and the self-inductance L D of the detection coil. Specifically, the following formula can be referred to,

[0144]

[0145] In the case where the frequency f of the alternating voltage (alternating current excitation source) U AC is 3 MHz and the self-inductance L D of the detection coil is 10 μH, the theoretical calculated value is about 177 pF. At the same time, through simulation optimization and experimental debugging, the actual capacitance value used is finally determined to achieve the best resonance performance. The second resistor R 2The gain factor of the resonant amplifier circuit can be adjusted according to the desired gain factor. e You can use LRB521S-40T1G model, the third capacitor R e The resistance value is 10kΩ, the second capacitor C e The capacitance value is 200nF.

[0146] The inventors' research also found that for induction heating products of smoking devices, heating components of different sizes, materials and shapes can be attributed to the different effects of the heating components on the equivalent impedance (including equivalent self-inductance and equivalent internal resistance) of the detection coil; and for induction heating products of cigarettes, in addition to the parameters of the heating components themselves (size, material, shape), the different positions of the heating components relative to the detection coil can also be attributed to the influence of the heating components on the equivalent impedance of the detection coil.

[0147] Although the present invention has been illustrated and described with reference to certain preferred embodiments of the present invention, it should be understood by those skilled in the art that the above is a further detailed description of the present invention in conjunction with specific embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. Those skilled in the art may make various changes in form and details, including making several simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A method for determining the consistency of an equivalent impedance of a heating component, the heating component being used in an electromagnetic induction aerosol generating system, characterized in that: include: In the same alternating magnetic field, respectively determine the detection voltage value of the detection coil when the heating component to be tested is placed, the standard voltage value of the detection coil when the standard heating component is placed, and the background voltage value of the detection coil when no heating component is placed; Determining a standard voltage change rate corresponding to the standard heating component based on the standard voltage value and the background voltage value; Determining a detection voltage change rate corresponding to the heating component to be tested based on the detection voltage value and the background voltage value; Determining the voltage sensitivity corresponding to the heating component to be tested based on the detection voltage change rate and the standard voltage change rate, wherein the voltage sensitivity is used to indicate the difference between the electromagnetic induction performance of the heating component to be tested and the standard heating component; Determining whether the absolute value of the voltage sensitivity is less than or equal to a preset threshold; When the absolute value of the voltage sensitivity is less than or equal to the preset threshold, it is determined that the equivalent impedance of the heating component to be tested is consistent with that of the standard heating component.

2. The method for determining the consistency of the equivalent impedance of a heating component according to claim 1, characterized in that: The step of determining the voltage sensitivity corresponding to the heating component to be tested based on the detection voltage change rate and the standard voltage change rate comprises: Based on the detection voltage change rate and the standard voltage change rate, determining a change rate difference between an absolute value of the detection voltage change rate and an absolute value of the standard voltage change rate; The voltage sensitivity corresponding to the heating component to be tested is determined based on the ratio of the change rate difference to the absolute value of the standard voltage change rate.

3. The method for determining the consistency of the equivalent impedance of a heating component according to claim 1, characterized in that: The step of determining the standard voltage change rate corresponding to the standard heating component based on the standard voltage value and the background voltage value comprises: Based on the standard voltage value and the background voltage value, determining a first voltage difference between an absolute value of the standard voltage value and an absolute value of the background voltage value; Based on the ratio of the first voltage difference to the absolute value of the standard voltage value, a standard voltage change rate corresponding to the standard heating component is determined.

4. The method for determining the consistency of the equivalent impedance of a heating component according to claim 1, characterized in that: The step of determining the detection voltage change rate corresponding to the heating component to be tested based on the detection voltage value and the background voltage value comprises: Based on the detection voltage value and the background voltage value, determining a second voltage difference between an absolute value of the detection voltage value and an absolute value of the background voltage value; Based on the ratio of the second voltage difference to the absolute value of the standard voltage value, the detection voltage change rate corresponding to the heating component to be tested is determined.

5. The method for determining the consistency of the equivalent impedance of a heating component according to claim 1, characterized in that: Also includes: When the voltage sensitivity is greater than the preset threshold, it is determined that the equivalent impedance of the heating component to be tested is inconsistent with that of the standard heating component.

6. The method for determining the consistency of the equivalent impedance of a heating component according to claim 1, characterized in that: The preset threshold is 1% to 3%.

7. A circuit for determining the consistency of equivalent impedance of a heating component, characterized in that: include: A resonant amplifier circuit, used to determine the voltage amplification signal of the detection coil, the resonant amplifier circuit comprising a first inductor, a first resistor and a first capacitor, wherein the first inductor and the first resistor come from the connected detection coil; A signal conditioning module, used for conditioning the voltage amplification signal from the resonant amplification circuit into a weak electric signal; A processor is used to process the weak current signal from the signal conditioning module and execute the method as claimed in any one of claims 1 to 6.

8. The circuit for determining the consistency of equivalent impedance of a heating component according to claim 7, characterized in that: The resonant amplifier circuit includes a series resonant amplifier circuit, which includes an AC voltage, the first inductor, the first resistor, the first capacitor, a second resistor and an amplifier element, wherein one end of the second resistor is connected to the AC voltage, the other end of the second resistor is connected to the inverting input end of the amplifier element and one end of the detection coil, the other end of the detection coil is connected to the output end of the amplifier element through the first capacitor, and the non-inverting input end of the amplifier element is grounded.

9. The circuit for determining the consistency of equivalent impedance of a heating component according to claim 7, characterized in that: The resonant amplifier circuit includes a parallel resonant amplifier circuit, which includes an AC voltage, the first inductor, the first resistor, the first capacitor, the second resistor, an amplifier element and a feedback resistor, wherein the detection coil, the first capacitor and the feedback resistor are connected in parallel with each other, one end of the second resistor is connected to the AC voltage, the other end of the second resistor is connected to the inverting input end of the amplifier element, one end of the feedback resistor, one end of the first capacitor and one end of the detection coil, the other end of the detection coil is connected to the output end of the amplifier element, and the non-inverting input end of the amplifier element is grounded.

10. The circuit for determining the equivalent impedance consistency of a heating component according to claim 8 or 9, wherein the resonant amplification circuit further comprises a diode, a third resistor and a second capacitor, wherein: The third resistor is connected in parallel with the second capacitor, the cathode of the diode is connected to the output end of the amplifying element, the anode of the diode is connected to one end of the third resistor and one end of the second capacitor, the other end of the third resistor and the other end of the second capacitor are grounded respectively; and / or, the AC voltage is provided by an AC voltage source chip.

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