Device for a resonant circuit

Abstract

A method and apparatus for use with an RLC resonant circuit for inductive heating of a susceptor of an aerosol-generating device is disclosed. The apparatus is arranged to determine a resonant frequency of the RLC resonant circuit; and determine, based on the determined resonant frequency, a first frequency for the RLC resonant circuit for causing the susceptor to be inductively heated, the first frequency being higher or lower than the determined resonant frequency. The apparatus can be arranged to control the drive frequency of the RLC resonant circuit to be the determined first frequency in order to heat the susceptor. An aerosol-generating device comprising the apparatus is also disclosed.

Description

[0001] This application is a divisional application of Chinese patent application No. 201880023202.4 entitled “Apparatus for Resonant Circuit” (based on international patent application No. PCT / EP2018 / 057835, filed on March 27, 2018). Technical Field

[0002] The present invention relates to an apparatus for use with an RLC resonant circuit, and more particularly, to an RLC resonant circuit for inductive heating of a sensor in an aerosol generation device. Background Technology

[0003] Smoking products such as cigarettes and cigars burn tobacco to produce tobacco smoke during use. Various efforts have been made to provide alternatives to these products by producing compounds that are released without combustion. Examples of such products are so-called "heated but not burned" products or tobacco heating devices or products that release compounds by heating a material but not burning it. This material can be, for example, tobacco or other non-tobacco products, which may or may not include nicotine. Summary of the Invention

[0004] According to a first aspect of the invention, there is an apparatus for use with an RLC resonant circuit for inductive heating of a sensor in an aerosol generating device, the apparatus being arranged to: determine the resonant frequency of the RLC resonant circuit; and then, based on the determined resonant frequency, determine a first frequency for the RLC resonant circuit to induce heating of the sensor, the first frequency being higher or lower than the determined resonant frequency.

[0005] The first frequency can be used to induce the sensor to be heated to a first degree under a given supply voltage. The first degree is less than a second degree, which is the degree to which the sensor is induced to be heated when the RLC resonant circuit is driven at the resonant frequency under a given voltage.

[0006] The device can be arranged to control the driving frequency of the RLC resonant circuit at a measured first frequency in order to heat the sensor.

[0007] The device can be configured to control the drive frequency to maintain a first frequency for a first time period.

[0008] The device can be arranged to control the drive frequency as one of a plurality of first frequencies that are different from each other.

[0009] The device can be arranged to control the drive frequency sequentially via multiple first frequencies.

[0010] The device can be arranged to select an order from one of a plurality of predetermined sequences.

[0011] The device can be arranged to control the driving frequency such that each of the first frequencies in the sequence is closer to the resonant frequency than the previous first frequency in the sequence, or to control the driving frequency such that each of the first frequencies in the sequence is further away from the resonant frequency than the previous first frequency in the sequence.

[0012] The device can be arranged to maintain one or more control drive frequencies at one or more first frequencies for one or more time periods.

[0013] The device can be configured to measure the electrical performance of an RLC circuit as a function of the driving frequency; and to determine the resonant frequency of the RLC circuit based on the measurement.

[0014] The device can be arranged to determine the electrical performance based on an RLC circuit at a first frequency, the electrical performance of which varies with the driving frequency of the RLC circuit.

[0015] Electrical properties can be measured as the voltage across the inductor in an RLC circuit, which is used to transfer energy to the sensor.

[0016] Electrical performance can be measured passively.

[0017] The electrical performance can be represented by the current generated in the sensing coil, which is used to transfer energy from the sensor in the RLC circuit, and the sensor is used to transfer energy to the sensor.

[0018] The electrical performance can be represented by the current generated in the coupling coil, which is used to transfer energy from the supply voltage element, which is used to supply voltage to the driving element, which is used to drive the RLC circuit.

[0019] The device can be arranged to determine the resonant frequency and / or first frequency of the RLC circuit substantially when the aerosol generating device is started up, and / or substantially when a new sensor is installed and / or a sensor is replaced in the aerosol generating device, and / or when a new sensor is installed and / or a sensor is replaced in the aerosol generating device.

[0020] The device can be arranged to measure the characteristics of the bandwidth representing the peak value of the response of an RLC circuit, the peak value being consistent with the resonant frequency; and to determine a first frequency based on the measured characteristics.

[0021] The device may include a driving element arranged to drive an RLC resonant circuit at one or more of a plurality of frequencies; wherein the device is arranged to control the driving element to drive the RLC resonant circuit at a determined first frequency.

[0022] The driving element may include an H-bridge driver.

[0023] The device may further include an RLC resonant circuit.

[0024] According to a second aspect of the invention, an aerosol generating apparatus is provided, comprising: a sensor arranged to heat an aerosol generating material to generate an aerosol in use, the sensor being arranged to induce heating via an RLC resonant circuit; and the apparatus refers to the first aspect.

[0025] The receptors can include one or more of nickel and steel.

[0026] The receptor may include a body with a nickel coating.

[0027] The nickel coating can have a thickness of generally less than 5 μm, or generally in the range of 2 μm to 3 μm.

[0028] Nickel coating can be electroplated onto the body.

[0029] The receptor can be or may include a low-carbon steel plate.

[0030] Low-carbon steel sheets can have a thickness ranging from approximately 10 μm to approximately 50 μm, or approximately 25 μm.

[0031] According to a third aspect of the invention, there is a method for use with an RLC resonant circuit for inductive heating of a sensor in an aerosol generating device, the method comprising: determining a resonant frequency of the RLC circuit; and determining a first frequency for the RLC resonant circuit for inductively heating the sensor, the first frequency being higher or lower than the determined resonant frequency.

[0032] The method may include controlling the driving frequency of the RLC resonant circuit at a measured first frequency in order to heat the sensor.

[0033] According to a fourth aspect of the invention, a computer program is provided that, when executed in a processing system, causes the processing system to perform the method according to the third aspect.

[0034] Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, which are given by way of example only and with reference to the accompanying drawings. Attached Figure Description

[0035] Figure 1 An aerosol generating apparatus according to an example is schematically shown;

[0036] Figure 2a An RLC resonant circuit according to the first example is schematically shown;

[0037] Figure 2bAn RLC resonant circuit according to the second example is schematically shown;

[0038] Figure 2c An RLC resonant circuit according to the third example is schematically shown;

[0039] Figure 3a The frequency response of an example RLC resonant circuit is schematically shown, indicating the resonant frequency;

[0040] Figure 3b The example frequency response of the example RLC resonant circuit is schematically shown, representing different drive frequencies;

[0041] Figure 3c The diagram schematically illustrates the temperature change over time of a receptor based on an example; and

[0042] Figure 4 It is a flowchart that schematically illustrates example methods. Detailed Implementation

[0043] Induction heating is the process of heating a conductive object (or inductor) through electromagnetic induction. An induction heater may include an electromagnet and a device for passing a changing current (e.g., alternating current) through the electromagnet. The changing current in the electromagnet generates a changing magnetic field. This changing magnetic field penetrates an inductor, which is properly positioned relative to the electromagnet, generating eddy currents within the inductor. The inductor has resistance to the eddy currents, and therefore the flow of the eddy currents against this resistance causes the inductor to be heated by Joule heating. In cases where the inductor comprises a ferromagnetic material, such as iron, nickel, or cobalt, heat can also be generated through hysteresis losses in the inductor, i.e., by changing the orientation of magnetic dipoles in the magnetic material, causing them to align with the changing magnetic field.

[0044] In induction heating, for example, heat is generated inside the sensor compared to conduction heating, allowing for rapid heating. Furthermore, no physical contact is required between the induction heater and the sensor, allowing for greater freedom in construction and application.

[0045] Electrical resonance occurs in a circuit at a specific resonant frequency when the imaginary parts of the impedances or admittances of the circuit elements cancel each other out. An example of a circuit demonstrating electrical resonance is an RLC circuit, consisting of a resistor (R) provided by a resistor, an inductor (L) provided by an inductor, and a capacitor (C) provided by a capacitor, all connected in series. Resonance occurs in an RLC circuit because the collapsing magnetic field of the inductor generates a current in its windings, charging the capacitor, while the discharging capacitor provides the current that establishes the magnetic field in the inductor. When the circuit is driven at the resonant frequency, the series impedance of the inductor and capacitor is at its minimum, while the current in the circuit is at its maximum.

[0046] Figure 1An example of an aerosol generating device 150 is schematically shown, including an RLC resonant circuit 100 for inductively heating an aerosol generating material 164 via a sensor 116. In some examples, the sensor 116 and the aerosol generating material 164 form an integral unit that can be inserted into and / or removed from the aerosol generating device 150 and may be disposable. The aerosol generating device 150 is handheld. The aerosol generating device 150 is arranged to heat the aerosol generating material 164 to produce an aerosol for inhalation by a user.

[0047] It should be noted that the term "aerosol-generating material" as used herein includes materials that provide components that evaporate upon heating (typically in the form of vapor or aerosol). Aerosol-generating materials may be materials that do not contain tobacco or materials that do contain tobacco. Aerosol-generating materials may include, for example, one or more of tobacco itself, tobacco derivatives, expanded tobacco, tobacco sheets, tobacco extracts, homogenized tobacco, or tobacco substitutes. Aerosol-generating materials may be in the form of ground tobacco, shredded tobacco, extruded tobacco, reconstituted tobacco, reconstituted raw materials, liquids, gels, gel sheets, powders, or agglomerates. Aerosol-generating materials may include one or more humectants, such as glycerol or propylene glycol.

[0048] Back Figure 1 The aerosol generating device 150 includes an external body 151 housing an RLC resonant circuit 100, a sensor 116, an aerosol generating material 164, a controller 114, and a battery 162. The battery is arranged to supply power to the RLC resonant circuit 100. The controller 114 is arranged to control the RLC resonant circuit 100, for example, controlling the voltage transmitted from the battery 162 to the RLC resonant circuit 100 and the frequency f driving the RLC resonant circuit 100. The RLC resonant circuit 100 is arranged for inductive heating of the sensor 116. The sensor 116 is arranged to heat the aerosol generating material 164 to generate aerosols in use. The external body 151 includes a nozzle 160 to allow aerosols generated in use to exit from the device 150.

[0049] In use, the user can activate the controller 114 via, for example, a known button (not shown) or a suction detector (not shown) to drive the RLC resonant circuit 100, for example, at the resonant frequency f of the RLC resonant circuit 100. r The resonant circuit 100 thus senses the heating sensor 116, thereby heating the aerosol generating material 164, and thus causing the aerosol generating material 164 to generate aerosol. The generated aerosol enters the air, is drawn into the device 150 through the air inlet (not shown), and is thus conveyed to the mouthpiece 160, where the aerosol leaves the device 150.

[0050] The controller 114 and the device 150, as a whole, can be arranged to heat the aerosol-generating material to a range of temperatures to evaporate at least one component of the aerosol-generating material without combustion. For example, the temperature range can be from about 50°C to about 350°C, such as between about 50°C and about 250°C, between about 50°C and about 150°C, between about 50°C and about 120°C, between about 50°C and about 100°C, between about 50°C and about 80°C, or between about 60°C and about 70°C. In some examples, the temperature range is between about 170°C and about 220°C. In some examples, the temperature range may differ from this range, with the upper limit of the temperature range exceeding 300°C.

[0051] What is needed is to control the degree to which the inductive heating sensor 116 heats the aerosol generating material 164. For example, controlling the speed and / or range of the heating sensor 116 may be useful. For example, controlling the heating of the aerosol generating material 164 according to a specific heating profile (via the sensor 116) may be useful, for example, to alter or enhance the characteristics of the generated aerosol, such as the properties, odor, and / or temperature of the generated aerosol. As another example, controlling the heating of the aerosol generating material 164 between different states (via the sensor 116) may be useful, such as a "hold" state and a "heat" state: in the "hold" state, the aerosol generating medium is heated to a relatively low temperature, which may be below the temperature at which the aerosol generating medium produces aerosols; in the "heat" state, the aerosol generating material 164 is heated to a relatively high temperature at which the aerosol generating material 164 produces aerosols. This control can help reduce the time from a given activation signal to the ability of the aerosol generating device 150 to produce aerosols. As a further example, the heating of the aerosol generating material 164 is controlled (via sensor 116) to ensure it does not exceed a certain range, for example, to ensure that the aerosol generating material is not heated to a temperature exceeding a certain temperature, such as a temperature that prevents it from burning or charring. For example, the temperature of sensor 116 may need to be kept below 400°C to ensure that sensor 116 does not cause combustion or charring of the aerosol generating material 164. It should be understood that, generally, there may be a difference between the temperature of sensor 116 and the temperature of aerosol generating material 164, for example, during the heating of sensor 116, such as in places where the heating rate is high. Therefore, it should be noted that in some examples, for example, the temperature of sensor 116, or the temperature that the sensor should not exceed, may be higher than the temperature that the aerosol generating material 164 needs to be heated to or the temperature that the aerosol generating material should not exceed.

[0052] One possible way to control the inductive heating of the sensor 116 via the RLC resonant circuit 100 is to control the supply voltage provided to the circuit, which in turn controls the current flowing in the circuit 100, and thus the energy transferred to the sensor 116 through the RLC resonant circuit 100, and therefore the degree to which the sensor 116 is heated. However, adjusting the supply voltage will result in increased cost, increased space requirements, and reduced efficiency due to losses in the voltage regulation components.

[0053] According to an example of the invention, a device (e.g., controller 114) is arranged to control the degree of heating of the heat sensor 116 by controlling the driving frequency f of the driving RLC resonant circuit 100. In the broad overview, and in the more detailed description below, the controller 114 is arranged to determine the resonant frequency f of the RLC resonant circuit 100. r This can be achieved, for example, by finding the resonant frequency of circuit 100, or by measuring the resonant frequency. The controller 114 is then configured based on the measured resonant frequency f. r The first frequency is determined to induce heating of the receptor; the first frequency is either higher or lower than the determined resonant frequency f. r The controller 114 is then configured to control the drive frequency f of the RLC resonant circuit 100 to a measured first frequency so that the sensor 116 is heated. This is because the first frequency is higher or lower than the resonant frequency f of the RLC resonant circuit 100. r (i.e., "polarization"), then driving the RLC circuit 100 at the first frequency will result in a smaller current I in the circuit 100 at a given voltage (compared to that at the resonant frequency f). r Compared to driving, and therefore at a given voltage, the sensor 116 and the circuit 100 at the resonant frequency f r Compared to when driven, it will be inductively heated to a lesser extent. Controlling the drive frequency of the resonant circuit at a first frequency thus allows for control of the degree of heating of the heating sensor 116 without needing to control the voltage supplied to the circuit, and thus allows for a cheaper, more space-efficient, and more power-efficient device 150.

[0054] Now, for reference Figure 2a An example of an RLC resonant circuit 100 is shown for inductive heating of a sensor 116. The resonant circuit 100 includes a resistor 104, a capacitor 106, and a sensor 108 connected in series. The RLC resonant circuit 100 has a resistor R, an inductor L, and a capacitor C.

[0055] The inductance L of circuit 100 is provided by inductor 108, which is arranged for inductive heating of inductor 116. Inductive heating of inductor 116 is achieved by an alternating magnetic field generated by inductor 108, resulting in Joule heating and / or hysteresis losses in inductor 116 as mentioned above. A portion of the inductance L of circuit 100 may be due to the permeability of inductor 116. The alternating magnetic field generated by inductor 108 is produced by an alternating current flowing through inductor 108. The alternating current flowing through inductor 108 is the alternating current flowing through RLC resonant circuit 100. Inductor 108 can be, for example, in the form of a coiled wire, such as a copper coil. Inductor 108 can include, for example, Litz wire, such as a wire comprising multiple individual insulated wires wound together. Litz wire can be particularly useful when the driving frequency used is in the MHz range because it can reduce power losses due to the well-known skin effect. At these relatively high frequencies, a lower inductance value is required. As another example, sensor 108 could be a coiled track on a printed circuit board. Using a coiled track on a printed circuit board can be useful because it provides rigidity and self-supporting properties, its cross-section eliminates the need for Litz wire (which may be too expensive), and allows for low-cost, highly repeatable mass production. Although one sensor 108 is shown, it should be readily understood that more than one sensor can be arranged for induction heating of one or more sensors 116.

[0056] The capacitance C of circuit 100 is provided by capacitor 106. Capacitor 106 may be, for example, a Class 1 ceramic capacitor, such as a COG capacitor. Capacitor C may also include stray capacitance of circuit 100; however, this may be negligible compared to the capacitance C provided by capacitor 106.

[0057] The resistance R of circuit 100 is provided by resistor 104, the resistance of the rails or wires connecting the components of resonant circuit 100, the resistance of inductor 108, and the resistance of the current flowing through resonant circuit 100 provided by sensor 116 arranged to transfer energy together with inductor 108. It should be understood that circuit 100 does not necessarily have to include resistor 104, and the resistance R in circuit 100 can be provided by the connecting rails or wires, inductor 108, and sensor 116.

[0058] Circuit 100 is driven by H-bridge driver 102. H-bridge driver 102 is a driving element used to provide AC power in resonant circuit 100. H-bridge driver 102 is connected to DC voltage supply V. SUPP 110, and connected to electrical ground GND112. DC voltage supply V SUPP110 can, for example, come from battery 162. H-bridge 102 can be an integrated circuit, or it can include discrete switching elements (not shown), which can be solid-state switches or mechanical switches. H-bridge driver 102 can, for example, be a high-efficiency bridge rectifier. It is known that H-bridge 102 can provide a DC voltage supply V in circuit 100 via a switching element (not shown) through the voltage across the inverted (and then stored) circuit. SUPP 110V AC. This can be useful because it allows the RLC resonant circuit to be powered by a DC battery and allows control over the frequency of the AC.

[0059] H-bridge driver 104 is connected to control unit 114. Controller 114 controls H-bridge 102 or components of the H-bridge (not shown) to provide AC current I in the RLC resonant circuit 100 at a given drive frequency f. For example, the drive frequency f can be in the range of MHz, such as 0.5MHz to 4MHz, or 2MHz to 3MHz. It should be understood that other frequencies f or frequency ranges can be used, depending on the specific resonant circuit 100 (and / or its components), controller 114, sensor 116, and / or drive element 102 used. For example, the resonant frequency f of the RLC circuit 100 should be... r The driving frequency f depends on the inductance L and capacitance C of circuit 100, and consequently on inductor 108, capacitor 106, and sensor 116. For example, the driving frequency f can be within the range of the resonant frequency f of the specific RLC circuit 100 and / or sensor 116 used. r The surrounding area. It should also be understood that the range of the resonant circuit 100 and / or the driving frequency or driving frequency f used can be selected based on other parameters of the given sensor 116. For example, to improve energy transfer from sensor 108 to sensor 116, it may be useful to provide a skin depth smaller than the thickness of the material of sensor 116 (i.e., the depth from the surface of sensor 116, where the alternating magnetic field from sensor 108 is absorbed), for example, a factor two to three times smaller. The skin depth varies for different materials and different constructions of sensor 116, and the skin depth decreases with increasing driving frequency f. In some examples, therefore, it may be advantageous to use a relatively high driving frequency. On the other hand, for example, to reduce the proportion of power supplied to resonant circuit 100 and / or driving element 102 that is lost as heat inside the electronics, it may be advantageous to use a lower driving frequency f. In some examples, a trade-off between these factors can therefore be selected as appropriate and / or as needed.

[0060] As mentioned above, the controller 114 is configured to measure the resonant frequency f of the RLC resonant circuit 100. r And then based on the measured resonant frequency fr A first frequency f is measured, and the RLC resonant circuit 100 is driven at the first frequency.

[0061] Figure 3a The frequency response 300 of the resonant circuit 100 is schematically shown. Figure 3a In the example, the frequency response 300 of the resonant circuit 100 is shown in a schematic diagram of the change of the current I flowing in the circuit 100 with the driving frequency f, wherein the circuit is driven by the H-bridge driver 104 at the driving frequency.

[0062] Figure 2a The resonant circuit 100 has a resonant frequency f r At this resonant frequency, the series impedance Z of inductor 108 and capacitor 106 is at its minimum, and therefore the current I is at its maximum. Thus, as... Figure 3a As shown, when the H-bridge driver 104 operates at the resonant frequency f r When driving circuit 100, the alternating current I in circuit 100 will be at its maximum value I. max Therefore, the current in sensor 108 is also at its maximum. The oscillating magnetic field generated by sensor 106 will therefore be maximized, and thus the induced heating of sensor 116 induced by sensor 106 will be maximized. When H-bridge driver 104 operates at a polarization frequency f (i.e., above or below the resonant frequency f), r When the drive circuit 100 is activated, the alternating current in the circuit 100 will be less than its maximum value, and therefore the current in the inductor 108 will also be less than its maximum value, and therefore the oscillating magnetic field generated by the inductor 106 will also be less than its maximum value, and therefore the sensor 116 heated by the inductor 106 will be less than its maximum value (for a given supply voltage V). SUPP 110). Therefore, in Figure 3a As can be seen, the frequency response 300 of the resonant circuit 100 has a peak value, which is concentrated at the resonant frequency f. r Above, and above or below the resonant frequency f r The frequency decreases at that point.

[0063] As mentioned above, the controller 114 is arranged to measure the resonant frequency f of the circuit 100. r .

[0064] In one example, controller 114 is arranged to find the resonant frequency f r (For example, the resonant frequency f of circuit 100 is determined from a memory (not shown)) r For example, the resonant frequency f of circuit 100 rIt can be calculated or measured, or otherwise determined in advance and pre-stored in memory (not shown), for example, during the manufacture of device 150. In another example, the resonant frequency f of circuit 100... r It can be connected to controller 114, for example, from user input (not shown), or from another device or input. A pre-stored resonant frequency is used as the resonant frequency f of circuit 100. r Its control circuitry allows for simple control of circuit 100. Even though the actual pre-stored resonant frequency is not exactly the same as the true resonant frequency of circuit 100, the pre-stored resonant frequency still provides useful control.

[0065] The resonant frequency f of circuit 100 (series RLC circuit) r It depends on the capacitance C and inductance L of circuit 100, and is given by the following formula:

[0066]

[0067] As mentioned above, the inductance L of circuit 100 is provided by inductor 108 arranged for inductive heating of sensor 116. At least a portion of the inductance L of circuit 100 is due to the permeability of sensor 116. The inductance L, and therefore the resonant frequency f of circuit 100, is also a factor. r Therefore, it may all depend on the specific sensor used and its position relative to sensor(s) 108, which may change from time to time. Furthermore, the permeability of sensor 116 can vary with the temperature of sensor 116. Therefore, in some examples, measuring the resonant frequency of circuit 100 may be useful for more accurate determination of the resonant frequency of circuit 100.

[0068] In some examples, to determine the resonant frequency of circuit 100, controller 114 is arranged to measure the frequency response 300 of RLC resonant circuit 100. For example, the controller can be arranged to measure the electrical performance of RLC circuit 100 as a function of the driving frequency f of the RLC circuit. Controller 114 may include a clock generator (not shown) to determine the absolute frequency of the driving RLC circuit 100. Controller 114 can be arranged to control H-bridge 104 to scan a range of driving frequencies f over a period of time. The electrical performance of RLC circuit 100 can be measured during the driving frequency, and therefore the frequency response 300 of RLC circuit 100 as a function of driving frequency f can be determined.

[0069] Electrical performance measurements can be passive measurements, that is, measurements that do not require any direct electrical contact with the resonant circuit 100.

[0070] For example, refer to again Figure 2a The example shown illustrates that electrical properties can represent the current generated in the sensing coil 120a by the inductor 108 of the RLC circuit 100. For example... Figure 2a As shown, sensing coil 120a is positioned for energy transfer from sensor 108 and arranged to detect current I flowing in coil 100. Sensing coil 120a can be, for example, a wound wire or a track on a printed circuit board. For example, if sensor 108 is a track on a printed circuit board, sensing coil 120a can be a track on the printed circuit board and positioned above or below sensor 108, for example, in a plane parallel to the plane where sensor 108 is located. As another example, where there is more than one sensor, sensing coil 120a can be placed between sensors 108 for energy transfer from two sensors. For example, if sensor 108 is a track on a printed circuit board and located in a plane parallel to another plane, sensing coil 120a can be a track on the printed circuit board placed between two sensors and located in a plane parallel to sensor 108. In any case, alternating current I flows in circuit 100, and therefore also in inductor 108, which causes inductor 108 to generate an alternating magnetic field. This alternating magnetic field induces a current in sensing coil 120a. The current induced in sensing coil 120a generates a voltage V across its terminals. IND The voltage V across the sensing coil 120a IND It can be measured and is proportional to the current I flowing in the RLC circuit 100. The voltage V across the sensing coil 120a is... IND The frequency response 300 of the circuit 100 can be measured by recording the changes in the driving frequency f of the resonant circuit 100 driven by the H-bridge driver 104. For example, the controller 114 can record the voltage V across the sensing coil 120a. IND The measurement of the frequency f is the frequency at which the H-bridge driver 104 drives AC current in the resonant circuit 100. Any controller can analyze the frequency response 300 to determine the resonant frequency f where the peak is concentrated. r And thus the resonant frequency of circuit 100 is determined.

[0071] Figure 2b Another example of passive measurement of the electrical performance of RLC circuit 100 is shown. Besides... Figure 2a The sensing coil 120a is replaced by the coupling coil 120b. Figure 2b and Figure 2a Same. For example... Figure 2bAs shown, the coupling coil 120b is positioned such that when the DC current flowing through the coupling coil changes due to the changing demands of the RLC circuit, it intercepts a portion of the magnetic field generated by the DC supply voltage line or rail 110. The magnetic field generated by the change in the current flowing in the DC supply voltage line or rail 110 induces a current in the coupling coil 120b, which in turn induces a voltage V across the coupling coil 120b. IND For example, although under ideal conditions the current flowing in the DC supply voltage line or rail 110 is simply direct current, in practice, for example due to incomplete switching in the H-bridge driver 104, the current flowing in the DC supply voltage line or rail 110 can be modulated to some extent by the H-bridge driver 104. This current modulation thus generates a current in the coupling coil, which flows through the voltage V across the coupling coil 120b. IND Measurement.

[0072] The voltage V across the coupling coil 120b IND The frequency response 300 of the circuit 100 can be measured and recorded as the H-bridge driver 104 drives the resonant circuit 100, and thus the frequency response 300 of the circuit 100 can be determined. For example, the controller 114 can record the voltage V across the coupling coil 120a. IND As the frequency f changes, it is measured to be the frequency at which the H-bridge driver 104 is controlled to drive AC current in the resonant circuit 100. The controller can then analyze the frequency response 300 to determine the resonant frequency f where the peak is concentrated. r And thus the resonant frequency of circuit 100 is determined.

[0073] It should be noted that in some examples, it may be necessary to reduce or remove current modulation components in the DC supply voltage line or rail 110, as current modulation may be caused by incompleteness in the H-bridge driver 104. This can be achieved, for example, by providing a bypass capacitor (not shown) across the H-bridge driver 104. It should be understood that in this case, the electrical performance of the RLC circuit 100 used to determine the frequency response 300 of circuit 100 may be measured in a manner different from that of the coupling coil 120b.

[0074] Figure 2c An example of active measurement of the electrical performance of an RLC circuit is shown. Besides... Figure 2a The induction coil 120a is composed of components 120c (e.g., passive differential circuit 120c), arranged to test the voltage V across the sensor 108. L Besides alternatives, Figure 2c and Figure 2a The same applies. As the current I in the resonant circuit changes, the voltage V across the inductor 108 also changes. L The voltage V across sensor 108 will change. LAs the driving frequency f of the H-bridge driver 104 driving the resonant circuit 100 changes, it can be measured and recorded, and thus the frequency response 300 of the circuit 100 can be determined. For example, the controller 14 can record the voltage V across the sensor 108 as the frequency f changes. L The frequency measured is the frequency at which the H-bridge driver 104 is controlled to drive AC current in the resonant circuit 100. The controller 114 can then analyze the frequency response 300 to determine the resonant frequency f where the peak is concentrated. r And thus the resonant frequency of circuit 100 is determined.

[0075] exist Figures 2a to 2c In each of the examples shown or other examples, controller 114 can analyze the frequency response 300 to determine the resonant frequency f. r The peak value is concentrated around the resonant frequency. For example, controller 114 can use known data analysis techniques to determine the resonant frequency from the frequency response. For example, the controller can directly derive the resonant frequency f from the frequency response data. r For example, controller 114 can determine the frequency f of the recorded maximum response as the resonant frequency f. r Alternatively, the two maximum responses can be measured and the average of these two frequencies f can be taken as the resonant frequency f. r As yet another example, controller 114 can match a function of current I (or another response, such as impedance, etc.) describing the frequency f for an RLC circuit to frequency response data, and infer or calculate the resonant frequency f from the matched function. r .

[0076] Measurement of the resonant frequency f based on the frequency response of RLC circuit 100 r This eliminates the need for numerical values ​​based on assumptions about the resonant frequency of a given circuit 100, sensor 1116, or sensor temperature, and thus provides a more accurate determination of the resonant frequency of circuit 100, and consequently provides more accurate frequency control for driving the resonant circuit 100. Furthermore, the control is more robust for sensor 116, resonant circuit 100, or the device 350 as a whole. For example, variations in the resonant frequency of resonant circuit 100 due to variations in the temperature of sensor 116 (e.g., variations in the inductance L of circuit 100 due to variations in the permeability in the sensor, resulting in variations in the temperature of sensor 116) can be described in the measurement.

[0077] In some examples, sensor 116 may be replaceable. For example, sensor 116 may be disposable and integral with, for example, an aerosol-generating material 164 arranged to be heated. When sensor 116 is replaced, the resonant frequency determined by measurement can thus illustrate the difference between different sensors 116, and / or the difference between different arrangements of sensor 116 relative to sensor 108. Furthermore, sensor 108, or any actual component of resonant circuit 100, may be replaceable, for example, after some use or after damage. Similarly, when sensor 108 is replaced, the determination of the resonant frequency can thus illustrate the difference between different sensors 108, and / or the difference between different arrangements of sensor 108 relative to different arrangements of sensor 116.

[0078] Therefore, the controller can be arranged to determine the resonant frequency of the circuit 100 generally when the aerosol generating device 150 is started, and / or generally when the new and / or replaced sensor 116 is installed in the aerosol generating device 150, and / or when the new and / or replaced sensor 108 is installed in the aerosol generating device 150.

[0079] As mentioned above, the controller 114 is arranged to determine a first frequency f based on the measured resonant frequency for inducing the sensor 16 to be heated, the first frequency being higher or lower than the measured resonant frequency (i.e., polarization).

[0080] Figure 3b The frequency response 300 of an example RLC resonant circuit 100 is schematically shown, and specific points (black circles) marked on the response 300 are shown relative to different driving frequencies f. A f B f C f' A .exist Figure 3b In the example, the frequency response 300 of the resonant circuit 100 is shown by the variation of the current I flowing in the circuit 100 with the driving frequency f of the driving circuit 100. The response 300 can correspond to, for example, a measured current I of the circuit 100 (or alternatively, another electrical property), such as that measured by the controller 114, as it varies with the driving frequency f of the driving circuit 100. Figure 3b As shown, and as described above, the response 300 is concentrated at the resonant frequency f. r The surrounding peak values. For a given supply voltage, when at the resonant frequency f r When driving the resonant circuit 100, the current I flowing in the resonant circuit 100 is at its maximum value I. max For a given supply voltage, when at a frequency higher than (i.e., a larger) the resonant frequency f... r frequency f' AWhen driving the resonant circuit, the current flowing in the resonant circuit 100 is less than the maximum value I. max Similarly, for a given supply voltage, when at a frequency lower than (i.e., a smaller) the resonant frequency f... r frequency f A f B f C When driving the resonant circuit, the current I flowing in the resonant circuit 100 A I B I C Less than the maximum value I max Since for a given voltage, and with resonant frequency f... r Compared to the driving circuit, with f A f B f C f' A In a driving circuit where a smaller current exists in the resonant circuit, less energy will be transferred from the inductor 108 to the sensor 116 in the resonant circuit 110. Therefore, for a given voltage, the energy transfer at the resonant frequency f will be less. r Compared to the degree of induction heating sensor 116 when the driving circuit is activated, the degree of induction heating sensor 116 will be smaller. Therefore, by controlling the resonant circuit 100 to operate at the first frequency f... A f B f C f' A One of the drivers is the controller, which can control the heating level of the sensor 116.

[0081] It should be understood that the further the frequency driven by the control resonant circuit 100 is from (above or below) the resonant frequency f, the better. r The less the receptor 116 will be heated by induction. Nevertheless, in f A f B f C f' A At each frequency, energy is transferred from the sensor 108 of the circuit 100 to the sensor 106, and the sensor 116 is heated in response to the induction.

[0082] In some examples, controller 114 can be activated at the measured resonant frequency f. r Add a predetermined amount or from the measured resonant frequency f r The first frequency f is determined by subtracting a predetermined amount from the given value, or by multiplying or dividing by a predetermined factor, or by any other operation. A f B f C f' AOne or more of them are driven by the first frequency control circuit 100. A predetermined amount, factor, or other operation can be set such that when the resonant circuit 100 operates at the first frequency f... A f B f C f' A When driven, the sensor 116 is still induced to heat, that is, so that the first frequency f A f B f C f' A The polarization near the sensor 116 is generally not sensitive to heating. Predetermined quantities, factors, or operations can be determined or calculated in advance, for example, during manufacturing, and stored, for example, in a memory (not shown) accessible by the controller 114. For example, the response 300 of circuit 100 can be measured in advance, and different currents I in circuit 100 can be observed. A I B I C This leads to the corresponding first frequency f A f B f C f' A The operation is measured and stored in a memory (not shown) accessible by the controller 114, and thus the sensor 116 is measured to be heated to different degrees. The controller can then select a suitable operation and therefore select a suitable first frequency f. A f B f C f' A In order to control the degree of induction heating sensor 116.

[0083] In some examples, as mentioned above, controller 114 can determine the change of the response 300 of circuit 100 with the drive frequency f, for example, by measuring and recording the changes in the electrical performance of circuit 100 with the drive frequency f of the driving circuit 100. As described above, this may be done, for example, when device 150 is started up or when components of circuit 100 are replaced. This can be done alternatively or additionally during operation of the device. Controller 114 can then determine the response 300 relative to the resonant frequency f by analyzing the measured response 300. r Determine the first frequency f A f B f C f' A For example, using the technique described above. Then the controller 114 can select a suitable first frequency f. A f B f C f' AThis allows for control over the degree to which the sensor 116 is induced to heat. Similarly, as described above, determining the first frequency based on the measured response of the resonant circuit 100 allows for more accurate and robust control against variations within the device 150, such as replacement of components of the resonant circuit 100 or changes in their relative positions, as well as variations in the response 300 itself, such as due to different temperatures or other conditions of the sensor 116, the resonant circuit 100, or the device 150.

[0084] In some examples, controller 114 may measure a characteristic of the bandwidth representing the peak value of response 300, and determine a first frequency f based on the measured characteristic. A f B f C f' A For example, the controller can determine the first frequency f based on the bandwidth B of the peak response of 300. A f B f C f' A .like Figure 3a As shown, the peak bandwidth B is at The full width of the peak at the resonant frequency f, in Hz. This characteristic, representing the bandwidth B of the peak of the response 300 of the resonant circuit 100, can be determined in advance, for example, during the manufacture of the device, and is pre-stored in a memory (not shown) readable by the controller via the controller 114. This characteristic represents the width of the peak of the response 300. Therefore, using this characteristic, the controller 114 can be provided with a simple method to determine the width of the peak of the response 300 relative to the resonant frequency f without analyzing the response 300. r The determination of the maximum heating value will result in a first frequency at which inductive heating reaches a given level. For example, controller 114 can determine the first frequency, for instance, by measuring the resonant frequency f. r Add or subtract a proportion or multiple representing the bandwidth B. For example, controller 114 can, for example, use the measured resonant frequency f r The first frequency is determined by adding or subtracting a proportion or multiple representing the bandwidth B. For example, the controller 114 can obtain the measured resonant frequency f. r And from the resonant frequency f r The first frequency is determined by adding or subtracting half the frequency of bandwidth B. Figure 3a As can be seen from this, this will cause the current I to be in The flow is in the circuit, and therefore for a given voltage, the degree of heating of the sensor 116 is reduced compared to driving the circuit 100 at the resonant frequency.

[0085] It should be understood that in other examples, the controller 114 may determine characteristics representing bandwidth B from the response 300 of the analysis circuit 100, for example from measurements of the electrical characteristics of the circuit 100 as the drive frequency f of the drive circuit 100 varies, as described above.

[0086] The first frequency f measured A f B f C f' A Above or below the resonant frequency f r (i.e., polarization), is driven by the first frequency control circuit 100, and therefore for a given supply voltage, with a resonant frequency f r Compared to the initial heating frequency, the degree of induction heating of the sensor 116 is less during driving. This enables control over the degree of induction heating of the sensor 116.

[0087] As described above, it may be useful to control the rate at which the sensor 116 is heated and / or the range to which the sensor 116 is heated. To achieve this, the controller 114 can control the driving frequency f of the resonant circuit 100 to a plurality of first frequencies f that are different from each other. A f B f C f' A One of them. For example, controller 114 can measure multiple first frequencies f. A f B f C f' A Each of these, then selects multiple first frequencies f according to the degree to which the heat sensor 116 (and thus the aerosol generating material 164) is heated. A f B f C f' A One of the appropriate ones.

[0088] As described above, controlling the heating of the aerosol-generating material 164 according to a specific heating curve (via sensor 116) may be useful, for example, to alter or enhance the characteristics of the generated aerosol, such as the properties, odor, and / or temperature of the generated aerosol. To achieve this, controller 114 may control the drive frequency f of resonant circuit 100 to sequentially pass through a plurality of first frequencies. For example, the sequence may correspond to a heating sequence, wherein the degree of induction heating of sensor 116 increases sequentially. For example, controller 114 may control the drive frequency f of resonant circuit 100 such that each first frequency in the sequence is closer to the resonant frequency than the previous first frequency in the sequence. For example, refer to Figure 3b The order can be the first frequency f C Then comes the first frequency f BThen comes the first frequency f A , where f A Compared to f B Closer to the resonant frequency f r , and f B Compared to f C Closer to the resonant frequency f r In this case, the current I flowing in the resonant circuit 100 will therefore be I0. C Then I B Then I A , where I C Less than I B They are successively smaller than I A Therefore, the intensity of the inductive heating sensor 116 increases over time. This can be useful for controlling and thus adjusting the real-time heating profile of the aerosol-generating material 164, for example, and thus adjusting aerosol delivery. The device 150 is therefore more flexible. For example, the sequence can be consistent with the heating sequence, where the intensity of the inductive heating sensor 116 increases sequentially. As another example, the controller 114 can control the drive frequency f of the drive resonant circuit 100 such that each first frequency in the sequence is further away from the resonant frequency compared to the previous first frequency in the sequence. For example, refer to... Figure 3b The order can be the first frequency f A Then comes the first frequency f. B Then comes the first frequency f C Therefore, the current I flowing in the resonant circuit 100 will correspondingly be I. A Then I B Then I C , where I C Less than I B Their values ​​are successively less than I. A Therefore, the degree of change in the inductive heating sensor 116 decreases over time. This could be useful, for example, for reducing the temperature of sensor 116 or aerosol generating medium 164 in a more controlled manner. Although in the sequence mentioned above, each frequency in the sequence is closer to (or further from) the resonant frequency than the previous frequency, it should be understood that this is not necessarily the case, and other sequences including any arrangement of multiple first frequencies can be followed as needed.

[0089] In some examples, controller 114 can select multiple first frequencies f from multiple predetermined sequences. A f B f C f' AThe order, or predetermined order, is stored, for example, in a memory (not shown) accessible to the controller 114. The order can be, for example, the heating or cooling order described above, or any other predetermined order. The controller 114 can determine which of the multiple orders is selected based on, for example, user input such as heating or cooling mode selection, the type of sensor 116 used, or the form of the aerosol generating medium 164 (e.g., identified by user input or from another identification device), operational inputs from all devices 150, such as the temperature of the sensor 116 or the aerosol generating medium 164, etc. This can be useful for controlling and thus adjusting the real-time heating profile of the aerosol generating material 164 according to user needs or the operating environment, and allows for a more flexible device 150.

[0090] In some examples, controller 114 can control the drive frequency f to a first frequency f A f B f C f' A Maintaining the first time period. In some examples, controller 114 can control the first frequency f at multiple first frequencies f. A f B f C f' A One or more of them are maintained for one or more corresponding time periods. This allows for further adjustment and flexibility of the heating profiles of the receptor 116 and the aerosol generating material 164.

[0091] As a concrete example, controlling the heating of the aerosol generating material 164 between different states or modes (via sensor 116) may be useful, such as a "hold" state and a "heat" state: in the "hold" state, the aerosol generating material 164 is heated to a relatively low "hold" or "preheat" level for a period of time; in the "heat" state, the aerosol generating material 164 is heated to a relatively high level for a period of time. As explained below, control between such states can help reduce the time it takes for the aerosol generating device 150 to generate a large amount of aerosol from a given activation signal.

[0092] exist Figure 3b The diagram schematically illustrates a specific example, showing a graph of the temperature T of the sensor 116 (or aerosol generating material 164) as a function of time t. Before time t1, the device 150 can be in an "off" state, i.e., no current flows in the resonant circuit 100. The temperature of the sensor 116 can therefore be the ambient temperature T. G For example, 21°C. At time t1, device 150 is switched to the "on" state, for example, by the user turning on device 150. Controller 114 controls circuit 100 at a first frequency f. BDrive. Controller 114 in time period P 12 Keep the driving frequency f at the first frequency f B Time period P 12 The time period during which it remains until controller 114 receives further input at time t2 can be unlimited, as described below. At a first frequency f B The drive circuit 100 causes AC current I B The fluid flows in circuit 100, and thus in sensor 108, thereby causing sensor 116 to be induced to heat. As sensor 116 is induced to heat, its temperature (and therefore the temperature of aerosol-generating material 164) remains constant for a period of time P. 12 The duration increases. In this example, receptor 116 (and aerosol-generating material 164) increases during time period P. 12 The medium was heated until it reached a stable temperature T. B Temperature T B It can be higher than the outside temperature T G The temperature is lower than the temperature at which aerosol-generating material 164 produces a large amount of aerosols. For example, temperature T... B The temperature can be 100°C. Device 150 is therefore in a "preheating" or "holding" state or mode, in which the aerosol-generating material 164 is heated, but generally no aerosol is generated, or a large amount of aerosol is not generated. At time t2, controller 114 receives an input, such as an activation signal. The activation signal can come from a user pressing a button (not shown) on device 150 or from a suction detector (not shown) known in itself. Upon receiving the activation signal, controller 114 can control circuit 100 at a resonant frequency f. r Drive. Controller 114 in time period P 23 With resonant frequency f r Maintain the drive frequency f. Time period P 23 This can be an unlimited time period, meaning it is maintained until the controller 114 receives further input at time t3, for example, until the user no longer presses the button (not shown), or the suction detector (not shown) is no longer activated, or until the maximum heating hold time has elapsed. At the resonant frequency f r The driving circuit 100 causes an alternating current I. MAX The current flows in circuit 100 and inductor 108, and thus, for a given voltage, maximally heats sensor 116. As sensor 116 is maximally heated, its temperature (and therefore the temperature of aerosol-generating material 164) increases over time period P. 23 The duration increases. In this example, receptor 116 (and aerosol-generating material 164) increases during time period P. 23 The internal heating allows it to reach a stable temperature T. MAX Temperature TMAX It can be higher than the "preheating" temperature T B The temperature, and generally equal to or higher than the temperature at which the aerosol-generating material 164 produces a large amount of aerosols. For example, temperature T MAX The temperature can be 300°C (although, of course, it can be different depending on the arrangement of material 164, sensor 116, the overall device 105, and / or other requirements and / or conditions). Therefore, device 150 is in a "heating" state or mode, where the aerosol-generating material 164 reaches a temperature that substantially generates aerosols, or a temperature that generates a large quantity of aerosols. Because the aerosol-generating material 164 is preheated, the time spent from the activation signal of device 150 to the generation of a large quantity of aerosols is reduced compared to the case where no "preheating" or "holding" state is applied. Device 150 therefore responds more quickly.

[0093] Although in the example above, controller 114 controls resonant circuit 100 to operate at resonant frequency f when an activation signal is received. r Driven, while in other examples, controller 114 can control resonant circuit 100 at a first frequency f. A f C Driven, the first frequency is higher than the first frequency f in the "preheat" mode or state. B Closer to the resonant frequency f r .

[0094] In some examples, the sensor 116 may include nickel. For example, the sensor 116 may include a body or substrate with a thin nickel coating. For example, the body may be a low-carbon steel plate with a thickness of about 25 μm. In other examples, the plate may be made of different materials, such as aluminum or plastic or stainless steel or other non-magnetic materials, and / or may have different thicknesses, such as between 10 μm and 50 μm. The body may be nickel-coated or electroplated. The nickel may have a thickness of, for example, less than 5 μm, such as between 2 μm and 3 μm. Another material may be used for coating or electroplating. Providing a relatively small thickness to the sensor 116 can help reduce the time required to heat the sensor 116 during use. The plate shape of the sensor 116 can allow for high thermal coupling efficiency from the sensor 116 to the aerosol generating material 164. The sensor 116 may be integrated into a consumable that includes the aerosol generating material 164. A thin plate of the sensor 116 material may be particularly useful for this purpose. The sensor 116 may be disposable. This sensor 116 can be cost-effective. In one example, the nickel-coated or nickel-plated sensor 116 can be heated to a temperature of about 200°C to about 300°C, which can be within the operating range of the aerosol generating device 150.

[0095] In some examples, the sensor 116 may be steel or comprise steel. The sensor 116 may be a low-carbon steel sheet with a thickness between about 10 μm and about 50 μm, for example, about 25 μm. Providing only a relatively small thickness to the sensor 116 can help reduce the time required to heat the sensor during use. The sensor 116 may be integrated into the device 105, for example, as opposed to integration with the disposable aerosol generating material 164. Nevertheless, the sensor 116 may be removable from the device 115, for example, making it possible to replace the sensor 116 after use, such as after degradation due to thermal and oxidative stress from overuse. Thus, the sensor 116 may be “semi-permanent” because it is not frequently replaced. Low-temperature steel sheet or foil or nickel-coated steel sheet or foil as the sensor 116 may be particularly suitable for this purpose because they are durable and therefore, for example, resistant to damage from repeated use and / or, for example, damage from repeated contact with the aerosol generating material 164. The plate-shaped sensor 116 allows for high thermal coupling efficiency from the sensor 116 to the aerosol generating material 164.

[0096] Curie temperature of iron T C It is 770℃. The Curie temperature T of low-carbon steel. C It could be around 770℃. The Curie temperature Tc of cobalt is... C The temperature is 1127°C. In one example, the low-carbon steel sensor 116 can be heated to a temperature of about 200°C to about 300°C, which can be within the operating range of the aerosol generating device 150. The sensor 116 has a Curie temperature T that is outside the operating temperature range of the sensor 116 in the device 150. C This may be useful because, in this case, the change in the response 300 of circuit 100 can be relatively small within the operating temperature range of sensor 116. For example, the change in the saturation magnetization of the sensor material (e.g., low-carbon steel) at 250°C may be relatively small, for example, a numerical change of less than 10% relative to the ambient temperature, and thus result in a small change in inductance L, and therefore a small change in the resonant frequency f of circuit 100. r The operating range can vary relatively little across different temperatures. This allows for accurate determination of the resonant frequency f based on predetermined values. r And therefore it can be used for simpler control.

[0097] Figure 4 This is a flowchart schematically illustrating a method 400 for controlling an RLC resonant circuit 100 of a sensor 116 used in an inductively heated aerosol generating device 150. In step 402, method 400 includes determining the resonant frequency f of the RLC circuit 100. r For example, by searching from memory or by measurement. In step 404, method 400 includes determining a first frequency f for sensing the heating sensor 116.A f B f C f' A The first frequency is higher or lower than the measured resonant frequency f r For example, this determination could be made by measuring the resonant frequency f. r Adding or subtracting a pre-stored amount, or based on a measurement of the frequency response of circuit 100. In step 406, method 400 includes controlling the driving frequency f of the RLC resonant circuit 100 to be a measured first frequency f. A f B f C f' A So that the heating sensor 116 can be heated. For example, the controller 114 can send a control signal to the H-bridge driver 114 to heat the sensor at a first frequency f. A f B f C f' A Drive RLC circuit 100.

[0098] Controller 114 may include a processor and memory (not shown). The memory may store instructions executable by the processor. For example, when executed on the processor, the memory may store instructions that cause the processor to perform method 400 described above and / or perform any or a combination of the functions in the examples described above. The instructions may be stored on any suitable storage medium, for example, on a non-transitory storage medium.

[0099] While some examples above mention that the frequency response 300 of the RLC resonant circuit 100 varies with the frequency f of the driving circuit in relation to the current flowing in the RLC resonant circuit 100, it should be understood that this is not necessarily the case, and in other examples, the frequency response 300 of the RLC circuit 100 can be any measurement related to the current I flowing in the RLC resonant circuit as a function of the driving circuit frequency f. For example, the frequency response 300 can be the response of the circuit impedance to frequency f, or as described above, it can be the voltage measured across the inductor, or the voltage or current of the induced current in the coupling coil caused by a change in the current flowing in the supply voltage line or track of the resonant circuit, or the voltage or current of the induced current in the sensing coil caused by the RLC resonant circuit inductor 108, or a signal from a non-inductive coupling coil or a non-inductive field sensor (e.g., a Hall effect sensor), as a function of the driving circuit frequency f. In each case, the frequency characteristics of the peak value of the frequency response can be determined.

[0100] Although the bandwidth B of the peak of response 300 is mentioned in some of the examples above, it should be understood that the width of any other peak of response 300 can be used instead. For example, the full width or half width of the peak at any predetermined response amplitude, or a fraction of the maximum response amplitude, can be used. It should also be understood that in other examples, the so-called "Q" or "quality" factor or value of resonant circuit 100 can be expressed as Q = f r / B and the bandwidth B and resonant frequency f of the resonant circuit 100 r Correspondingly, Q can be determined and / or measured and used as a frequency characteristic in place of bandwidth B and / or resonant frequency f. r This is similar to the example described above regarding the application of appropriate factors. Therefore, it should be understood that in some examples, the Q factor of circuit 100 can be measured or determined, and the resonant frequency f of circuit 100 can be determined based on the measured Q factor. r The bandwidth B of circuit 100 and / or the first frequency of circuit 100.

[0101] While the peak value mentioned in the above example is associated with the maximum value, it is easy to understand that this does not necessarily have to be the case, and it depends on the measured frequency response 300 and how it is measured; the peak value can be associated with the minimum value. For example, at resonance, the impedance of the RLC circuit 100 is at its minimum value, and therefore, when the impedance varies with the driving frequency f (e.g., used as the frequency response 300), the peak value of the frequency response 300 of the RLC circuit will be associated with the minimum value.

[0102] Although some examples above describe the controller 114 being arranged to measure the frequency response 300 of the RLC resonant circuit 100, it should be understood that in other examples, the controller 114 may determine the resonant frequency or first frequency by analyzing the frequency response data via a separate measurement or control system (not shown), or by directly determining the resonant frequency or first frequency by, for example, by connecting them via separate control or measurement systems. The controller 114 can then control the frequency driving the RLC circuit 100 to the first frequency thus determined.

[0103] Although some examples above describe controller 114 as being arranged to determine a first frequency and control the resonant frequency of the drive circuit, it should be understood that this is not necessarily the case, and in other examples, the device that is or includes controller 114 may be arranged to determine the first frequency and control the frequency of the drive resonant circuit. The device may be arranged to determine the first frequency by, for example, the method described above. The device may be arranged to send a control signal to, for example, H-bridge driver 102 to control the resonant circuit 100 to drive at the thus determined first frequency. It should be understood that the device or controller 114 does not necessarily need to be part of the aerosol generating device 150 as a whole, and may, for example, be a separate device or controller 114 used with the aerosol generating device 150. Furthermore, it should be understood that the device or controller 114 does not necessarily need to be used to control the resonant circuit, and / or does not need to be arranged to drive and control the frequency of the resonant circuit, and in other examples, the device or controller 114 may be arranged to determine the first frequency but does not itself control the resonant circuit. For example, given a measured first frequency, the device or controller 114 can send that information or information representing the measured first frequency to a separate controller (not shown), or the separate controller (not shown) can obtain information or instructions from the device or controller 114, and the separate controller (not shown) can then control the frequency of the drive resonant circuit based on that information or instructions, for example, controlling the frequency of the drive resonant circuit to be the first frequency, for example, controlling the H-bridge driver 102 to drive the resonant circuit at the first frequency.

[0104] Although the example above describes a device or controller 114 for use with an RLC resonant circuit for inductive heating of the sensor in an aerosol generating device, this is not required to be the case, and in other examples, the device or controller 114 can be used with an RLC resonant circuit for inductive heating of the sensor in any device, such as any inductive heating device.

[0105] Although the example above describes an RLC resonant circuit driven by H-bridge driver 102, this is not required, and in other examples, the RLC resonant circuit 100 can be driven by any suitable driving element to provide AC power in the resonant circuit 100, such as an oscillator, etc.

[0106] The examples above should be understood as illustrative examples of the invention. It should be understood that any feature described with respect to any example can be used alone or in combination with other described features, and can also be used in combination with one or more features of any other example, or any other combination of other examples. Furthermore, equivalents and modifications not described above may be employed without departing from the scope of the invention as defined by the appended claims.

Claims

1. A device for use with an RLC resonant circuit for inductive heating of a sensor in an aerosol generation device, said device being arranged as follows: The resonant frequency of the RLC resonant circuit was measured. Based on the measured resonant frequency, a first frequency is determined for the RLC resonant circuit to induce heating of the sensor, wherein the first frequency is higher or lower than the measured resonant frequency; and The driving frequency of the RLC resonant circuit is controlled at the measured first frequency in order to heat the sensor; in, The first frequency causes the aerosol generating material of the aerosol generating device in the heating state to be heated to a first temperature, and wherein the first frequency causes the aerosol generating material of the aerosol generating device in the holding state to be heated to a second temperature, wherein the second temperature is higher than the ambient temperature but lower than the first temperature.

2. The apparatus according to claim 1, wherein, The first frequency is used to induce the sensor to be heated to a first degree under a given supply voltage, the first degree being less than a second degree, the second degree being the degree to which the sensor is induced to be heated when the RLC resonant circuit is driven at the resonant frequency under the given supply voltage.

3. The apparatus according to claim 2, wherein, The device is arranged such that: The drive frequency is controlled to maintain the first frequency for a first time period.

4. The apparatus according to claim 3, wherein, The device is arranged such that: The driving frequency is one of a plurality of first frequencies that are different from each other.

5. The apparatus according to claim 4, wherein, The device is arranged such that: The driving frequency is controlled sequentially by the plurality of first frequencies.

6. The apparatus according to claim 5, wherein, The device is arranged such that: Choose the order from one of a plurality of predetermined orders.

7. The apparatus according to claim 5 or 6, wherein, The device is arranged such that: Controlling the driving frequency such that each of the first frequencies in the sequence is closer to the resonant frequency than the previous first frequency in the sequence, or The driving frequency is controlled such that each of the first frequencies in the sequence is further away from the resonant frequency than the first frequency preceding it in the sequence.

8. The apparatus according to claim 4, wherein, The device is arranged such that: The driving frequency is controlled to remain for one or more time periods using one or more of the plurality of first frequencies.

9. The apparatus according to claim 1 or 2, wherein, The device is arranged such that: The electrical performance of the RLC resonant circuit was measured based on the driving frequency; and The resonant frequency of the RLC resonant circuit is determined based on the measurement.

10. The apparatus according to claim 9, wherein, The device is arranged such that: The first frequency is determined based on the electrical performance of the RLC resonant circuit as measured according to the driving frequency of the RLC resonant circuit.

11. The apparatus according to claim 9, wherein, The electrical performance is the voltage measured across the inductor in the RLC resonant circuit, which is used to transfer energy to the sensor.

12. The apparatus according to claim 9, wherein, The electrical performance is measured passively.

13. The apparatus according to claim 12, wherein, The electrical properties refer to the current generated in the sensing coil, which is used to transfer energy from the sensor in the RLC resonant circuit, which is used to transfer energy to the sensor.

14. The apparatus according to claim 12, wherein, The electrical properties refer to the current induced in the coupling coil, which is used to transfer energy from the supply voltage element, which is used to supply voltage to the driving element, which is used to drive the RLC resonant circuit.

15. The apparatus according to claim 1 or 2, wherein, The device is arranged such that: The resonant frequency and / or the first frequency of the RLC resonant circuit are determined when the aerosol generating device is started and / or when a new and / or replaced sensor is installed in the aerosol generating device.

16. The apparatus according to claim 1 or 2, wherein, The device is arranged such that: The bandwidth characteristic representing the peak value of the response of the RLC resonant circuit is determined, the peak value corresponding to the resonant frequency; and The first frequency is determined based on the measured characteristics.

17. The apparatus according to claim 1 or 2, wherein, The device includes: A driving element is arranged to drive the RLC resonant circuit at one or more of a plurality of frequencies; The device is arranged to control the driving element to drive the RLC resonant circuit at the measured first frequency.

18. The apparatus according to claim 17, wherein, The driving element includes an H-bridge driver.

19. The apparatus according to claim 1 or 2, wherein the apparatus further comprises the RLC resonant circuit.

20. An aerosol generating apparatus, comprising: A sensor is arranged to heat an aerosol-generating material to generate an aerosol in use, the sensor being arranged to sense the heating via an RLC resonant circuit; The apparatus according to any one of claims 1 to 19.

21. The aerosol generating apparatus according to claim 20, wherein, The receptor comprises one or more of nickel and steel.

22. The aerosol generating apparatus according to claim 21, wherein, The receptor includes a body with a nickel coating.

23. The aerosol generating apparatus according to claim 22, wherein, The nickel coating has a thickness of less than 5 μm.

24. The aerosol generating apparatus according to claim 23, wherein, The nickel coating has a thickness in the range of 2 μm to 3 μm.

25. The aerosol generating apparatus according to claim 22, wherein, The nickel coating is electroplated onto the body.

26. The aerosol generating apparatus according to any one of claims 21 to 24, wherein, The sensor is made of low-carbon steel plate.

27. The aerosol generating apparatus according to any one of claims 21 to 24, wherein, The sensor comprises a low-carbon steel plate.

28. The aerosol generating apparatus according to claim 26, wherein, The low-carbon steel plate has a thickness ranging from 10 μm to 50 μm.

29. The aerosol generating apparatus according to claim 28, wherein, The low-carbon steel plate has a thickness of 25 μm.

30. A method for use with an RLC resonant circuit for inductive heating of a sensor in an aerosol generation device, the method comprising: The resonant frequency of the RLC resonant circuit was measured. A first frequency is determined for the RLC resonant circuit to induce heating of the sensor, the first frequency being higher or lower than the determined resonant frequency; as well as The driving frequency of the RLC resonant circuit is controlled at the measured first frequency in order to heat the sensor. Wherein, the first frequency causes the aerosol generating material of the aerosol generating device in the heating state to be heated to a first temperature, and wherein, the first frequency causes the aerosol generating material of the aerosol generating device in the holding state to be heated to a second temperature, wherein, the second temperature is higher than the ambient temperature but lower than the first temperature.

31. A computer program, when executed in a processing system, causes the processing system to perform the method according to claim 30.

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