Impedance matching device and control method

Abstract

The invention relates to the technical field of impedance matching, particularly provides an impedance matching device and a control method, and aims at solving the problems that an existing dual-frequency matcher structure is large in device size, and internal devices are complex to replace, disassemble and assemble and interfere with one another. In order to achieve the purpose, the control method of the impedance matching device comprises the steps that the working frequency of a power source and the equivalent impedance of a matching network are obtained; based on the magnitude relationship between the real part of the equivalent impedance and the first preset real part impedance, the bypass state and the series connection state of the first inductor are controlled; based on the magnitude relation between the real part of the equivalent impedance and the second preset real part impedance, the bypass state and the series connection state of the third inductor are controlled; and controlling the bypass state and the series connection state of the second inductor based on the magnitude relationship between the imaginary part of the equivalent impedance and the preset imaginary part impedance. The inductance state and the capacitance value are adjusted in real time, it is ensured that the reflection coefficient is rapidly converged to the threshold value, and the energy transmission efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of impedance matching, and specifically provides an impedance matching device and a control method. Background Art

[0002] Power radio frequency sources have been widely used in fields such as vacuum coating, semiconductor etching, and inductively coupled plasma heating. Usually, the load impedance is not equal to the internal resistance of the radio frequency source. If the radio frequency source and the load are directly connected, there will be different degrees of mismatch. Impedance mismatch will cause power reflection on the transmission line, and the energy cannot be fully received by the load, reducing the transmission efficiency. Therefore, a matching network needs to be set between the radio frequency source (or the end of the transmission line) and the load.

[0003] During the experimental test process, it is necessary to meet the matching requirements for plasma chambers operating at different frequency bands. During the verification process, a single matcher can only meet the matching state of a single frequency. Simply using the existing matcher structure to adapt to two operating frequencies, there is an impedance range mismatch or the matching position changes from the central optimal matching point to the edge position state. This not only easily results in an unstable matching state but also reduces the matching speed. The common dual-frequency matcher structures in the market mostly use two different matching structures to meet the matching requirements under two operating frequencies. The two matching structures use a structure form with two input ports and one output port. Therefore, common dual-frequency matchers have problems such as large device volume, complex replacement and disassembly of internal devices, and mutual interference. At the same time, the two structures require two different impedance detection and control processing modules, increasing the manufacturing cost.

[0004] Correspondingly, a new technical solution is needed in this field to solve the above problems. Summary of the Invention

[0005] The present invention aims to solve the above technical problems and addresses the problems of existing dual-frequency matcher structures that mostly use two different matching structures, resulting in large device volume, complex replacement and disassembly of internal devices, and mutual interference.

[0006] The present invention provides an impedance matching device, which is connected between a power supply and a load and includes a matching network. The matching network includes a series branch, a parallel branch, and a control component. The series branch connects the power supply and the load in series, and a first inductor, a first adjustable capacitor, and a second inductor are connected in series on the series branch. The two ends of the parallel branch are connected to the series branch, and the parallel branch is connected in parallel with the first adjustable capacitor, the second inductor, and the load. A second adjustable capacitor and a third inductor are provided on the parallel branch. The control component is connected to the first inductor, the second inductor, and the third inductor for control, and the control component is configured to be able to separately control each inductor to be in a bypass state.

[0007] In the case of adopting the above technical solution, through the collaborative design of the series branch and the parallel branch, combined with the independent bypass control of the inductor by the control component, impedance matching at at least two frequencies is achieved. Through the first adjustable capacitor and the second adjustable capacitor, impedance matching at a single frequency can be achieved. Through the independent bypass control of the inductor by the control component, impedance matching at other frequencies can be achieved. It adapts to different operating frequencies and solves the problem of poor frequency adaptability of traditional single matchers. There is no need for two sets of independent detection and control modules, reducing the hardware complexity and manufacturing cost.

[0008] In the specific embodiment of the above impedance matching device, the control component includes a first switch, a second switch, and a third switch. The first switch is arranged in parallel with the first inductor and is configured to enable the first inductor to be in a bypass state when the first switch is in a closed state; the second switch is arranged in parallel with the second inductor and is configured to enable the second inductor to be in a bypass state when the second switch is in a closed state; the third switch is arranged in parallel with the third inductor and is configured to enable the third inductor to be in a bypass state when the third switch is in a closed state.

[0009] In the case of adopting the above technical solution, by controlling the bypass states of each inductor by paralleling three independent switches respectively, the coupling interference between different inductors is avoided, and the matching accuracy and stability are improved.

[0010] In the specific embodiment of the above impedance matching device, the impedance matching device further includes a frequency detection module, an impedance detection module, a motor control module, and a switch control module. The frequency detection module is configured to be able to detect the operating frequency of the power supply; the impedance detection module is configured to be able to detect and calculate the equivalent impedance of the matching network; the motor control module is configured to be able to control the capacitance values of the first adjustable capacitor and the second adjustable capacitor; the switch control module is configured to be able to control the opening and closing of the first switch, the second switch, and the third switch.

[0011] The present invention also discloses a control method for an impedance matching device. The impedance matching device is the above device. The control method for the impedance matching device includes:

[0012] Obtain the operating frequency of the power supply and the equivalent impedance of the matching network;

[0013] Based on the magnitude relationship between the real part of the equivalent impedance and the first preset real part impedance, control the bypass state and the series connection state of the first inductor;

[0014] Based on the magnitude relationship between the real part of the equivalent impedance and the second preset real part impedance, control the bypass state and the series connection state of the third inductor;

[0015] Based on the magnitude relationship between the imaginary part of the equivalent impedance and the preset imaginary part impedance, control the bypass state and series connection state of the second inductor;

[0016] Calculate the reflection coefficient;

[0017] Control the capacitance value of the adjustable capacitor until the reflection coefficient is less than the preset threshold;

[0018] Wherein, the first preset real part impedance is the real part impedance value corresponding to the second adjustable capacitor at the 10%-30% position; the second preset real part impedance is the real part impedance value corresponding to the second adjustable capacitor at the 70%-90% position; the preset imaginary part impedance is the imaginary part impedance value corresponding to the first adjustable capacitor at the 10%-30% position.

[0019] In the case of adopting the above technical solution, through the dynamic comparison of the real part / imaginary part impedance with the preset value and the combined linkage control of the position of the adjustable capacitor, the inductor state and the capacitance value can be adjusted in real time to ensure that the reflection coefficient quickly converges within the threshold and improve the energy transmission efficiency.

[0020] In a specific embodiment of the control method of the impedance matching device, the step of controlling the bypass state and series connection state of the first inductor based on the magnitude relationship between the real part of the equivalent impedance and the first preset real part impedance further includes:

[0021] If the real part of the equivalent impedance is less than the first preset real part impedance, control the first inductor to be in the series connection state;

[0022] If the real part of the equivalent impedance is greater than or equal to the first preset real part impedance, control the first inductor to be in the bypass state.

[0023] In a specific embodiment of the control method of the impedance matching device, the step of controlling the bypass state and series connection state of the third inductor based on the magnitude relationship between the real part of the equivalent impedance and the second preset real part impedance further includes:

[0024] If the real part of the equivalent impedance is greater than the second preset real part impedance, control the third inductor to be in the series connection state;

[0025] If the real part of the equivalent impedance is less than or equal to the second preset real part impedance, control the third inductor to be in the bypass state.

[0026] In a specific embodiment of the control method of the impedance matching device, the step of controlling the bypass state and series connection state of the second inductor based on the magnitude relationship between the imaginary part of the equivalent impedance and the preset imaginary part impedance further includes:

[0027] If the imaginary part of the equivalent impedance is less than the preset imaginary part impedance, control the second inductor to be in the series connection state;

[0028] If the imaginary part of the equivalent impedance is greater than or equal to the preset imaginary part impedance, control the second inductor to be in the bypass state.

[0029] In the specific implementation manner of the control method of the impedance matching device described above, the calculation method of the equivalent impedance includes:

[0030] When the first inductor, the second inductor, and the third inductor are all in the bypass state, the calculation method of the equivalent impedance is as follows:

[0031] Z0 = X C1 + X C2 / / R s

[0032] When the first inductor is in the series connection state and the second inductor and the third inductor are both in the bypass state, the calculation method of the equivalent impedance is as follows:

[0033]

[0034] When the second inductor is in the series connection state and the first inductor and the third inductor are both in the bypass state, the calculation method of the equivalent impedance is as follows:

[0035]

[0036] When the third inductor is in the series connection state and the first inductor and the second inductor are both in the bypass state, the calculation method of the equivalent impedance is as follows:

[0037]

[0038] Among them, Z0 is the equivalent impedance when the first inductor, the second inductor, and the third inductor are all in the bypass state, X C1 is the reactance of the first adjustable capacitor, X C2 is the reactance of the second adjustable capacitor, R s is the internal resistance of the RF power supply; is the equivalent impedance when the first inductor is in the series connection state and the second inductor and the third inductor are both in the bypass state, is the reactance of the first inductor, is the equivalent impedance when the second inductor is in the series connection state and the first inductor and the third inductor are both in the bypass state, is the reactance of the second inductor, is the equivalent impedance when the third inductor is in the series connection state and the first inductor and the second inductor are both in the bypass state, is the reactance of the third inductor.

[0039] In the specific implementation of the control method of the impedance matching device described above, after the steps of obtaining the operating frequency and the equivalent impedance in the control method of the impedance matching device, the following steps are further included:

[0040] Obtain the operating frequency of the power supply;

[0041] Determine whether the current operating frequency is the first preset operating frequency or the second preset operating frequency.

[0042] When the operating frequency is the first preset operating frequency, directly control the capacitance value of the adjustable capacitor until the reflection coefficient is less than the preset threshold; when the operating frequency is the second preset operating frequency, based on the set conditions, control the bypass state and the series connection state of the first inductor, the second inductor, and the third inductor.

[0043] In the specific implementation of the control method of the impedance matching device described above, the calculation method of the reflection coefficient is as follows:

[0044]

[0045] Where Γ is the reflection coefficient, Z_current is the current equivalent impedance, and Zs is the equivalent impedance of the power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings, in which:

[0047] Figure 1 is the circuit diagram of the embodiment of the impedance matching device of the present invention;

[0048] Figure 2 is the partial circuit diagram of the embodiment when the first inductor of the impedance matching device of the present invention is connected to the circuit;

[0049] Figure 3 is the partial circuit diagram of the embodiment when the third inductor of the impedance matching device of the present invention is connected to the circuit;

[0050] Figure 4 is the partial circuit diagram of the embodiment when the second inductor of the impedance matching device of the present invention is connected to the circuit;

[0051] Figure 5 is the flowchart of the main steps of the control method of the impedance matching device of the present invention;

[0052] Figure 6 is the flowchart of a possible implementation of the control method of the impedance matching device of the present invention;

[0053] Figure 7It is a schematic diagram of the matching range when different inductors of the impedance matching device of the present invention are in series connection state. Detailed implementation manners

[0054] The preferred implementation manners of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners are only used to explain the technical principle of the present application and are not used to limit the protection scope of the present application. Those skilled in the art can adjust them as needed to adapt to specific application scenarios.

[0055] It should be noted that in the description of the present application, unless otherwise clearly specified and limited, terms such as "arrangement" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or other connections; it can be directly connected or indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to specific situations. In addition, terms such as "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present application, "a plurality of" means at least two.

[0056] As Figures 1-4 As shown, to solve the problems that the dual-frequency matcher structure mostly adopts two different matching structures, which have large device volume, complex replacement and disassembly of internal devices, and mutual interference, the present invention provides an impedance matching device. An impedance matching device is connected between a power supply and a load and includes a matching network. It is characterized in that the matching network includes a series branch, a parallel branch and a control component; the series branch connects the power supply and the load in series, and a first inductor, a first adjustable capacitor and a second inductor are connected in series on the series branch; both ends of the parallel branch are connected to the series branch, the parallel branch is connected in parallel with the first adjustable capacitor, the second inductor and the load, and a second adjustable capacitor and a third inductor are arranged on the parallel branch; the control component is controllably connected to the first inductor, the second inductor and the third inductor, and the control component is configured to be able to separately control each inductor to be in a bypass state. In this way, through the collaborative design of the series branch and the parallel branch, combined with the independent bypass control of the inductor by the control component, impedance matching at at least two frequencies is achieved. Through the first adjustable capacitor and the second adjustable capacitor, impedance matching at a single frequency can be achieved. Through the independent bypass control of the inductor by the control component, impedance matching at other frequencies can be achieved. It adapts to different operating frequencies and solves the problem of poor frequency adaptability of traditional single matchers. There is no need for two sets of independent detection and control modules, which reduces the hardware complexity and manufacturing cost.

[0057] As Figure 1As shown, in one or more embodiments, a series branch connects a power source and a load in series. A first inductor, a first adjustable capacitor, and a second inductor are connected in series between the power source and the load on the series branch. One end of a parallel branch is connected to the series branch between the first inductor and the first adjustable capacitor, and the other end of the parallel branch is connected to the end of the load away from the second inductor.

[0058] As Figure 1 shown, in one or more embodiments, the control component includes a first switch, a second switch, and a third switch. The first switch is arranged in parallel with the first inductor and is configured to put the first inductor in a bypass state when the first switch is in a closed state. The second switch is arranged in parallel with the second inductor and is configured to put the second inductor in a bypass state when the second switch is in a closed state. The third switch is arranged in parallel with the third inductor and is configured to put the third inductor in a bypass state when the third switch is in a closed state. By controlling the bypass states of the inductors respectively through three independent switches in parallel, the coupling interference between different inductors is avoided, and the matching accuracy and stability are improved. It should be noted that the first switch, the second switch, and the third switch may not be provided, and instead, the first inductor, the second inductor, and the third inductor may be adjustable inductors.

[0059] As Figure 1 shown, in one or more embodiments, the impedance matching device includes a motor control module, a switch control module, a frequency detection module, and an impedance detection module. The motor control module is connected to the first adjustable capacitor and the second adjustable capacitor, and the capacitance values of the first adjustable capacitor and the second adjustable capacitor are adjusted through the motor control module. The switch control module is connected to the first switch, the second switch, and the third switch for control. The switch control module can receive a control instruction and then control the opening and closing of the first switch, the second switch, and the third switch. The frequency detection module is used to detect the operating frequency of the power source. The impedance detection module is used to detect and calculate the equivalent impedance. It should be further noted that the specific compositions of the above-mentioned various modules are all prior arts and will not be elaborated here.

[0060] As Figure 2 shown, in one or more embodiments, the impedance matching device further includes a driving motor for changing the value of the adjustable capacitor. By controlling the rotation of the driving motor, the position of the adjustable capacitor is changed.

[0061] As Figure 5 shown, the present invention also discloses a control method for an impedance matching device. The control method for the impedance matching device includes:

[0062] S101, obtaining the operating frequency of the power source and the equivalent impedance of the matching network. For example, the operating frequency of the power source, that is, the frequency of the current in the circuit, is detected through the frequency detection module, and the equivalent impedance in the circuit is detected and calculated through the impedance detection module.

[0063] S102. Control the bypass state and series connection state of the first inductor based on the magnitude relationship between the real part of the equivalent impedance and the first preset real part impedance. For example, the first preset real part impedance is the real part impedance value ZC2_10 corresponding to the second adjustable capacitor at the 10% position. Compare the real part of the equivalent impedance with the first preset real part impedance, and control the bypass state and series connection state of the first inductor through the first switch. When the first switch is closed, the first inductor is in the bypass state. When the first switch is open, the first inductor is in the series connection state.

[0064] S103. Control the bypass state and series connection state of the third inductor based on the magnitude relationship between the real part of the equivalent impedance and the second preset real part impedance. For example, the second preset real part impedance is the real part impedance value ZC2_90 corresponding to the second adjustable capacitor at the 90% position. Compare the real part of the equivalent impedance with the second preset real part impedance, and control the bypass state and series connection state of the third inductor through the third switch. When the third switch is closed, the third inductor is in the bypass state. When the third switch is open, the third inductor is in the series connection state.

[0065] S104. Control the bypass state and series connection state of the second inductor based on the magnitude relationship between the imaginary part of the equivalent impedance and the preset imaginary part impedance. For example, the preset imaginary part impedance is the imaginary part impedance value ZC1_10 corresponding to the first adjustable capacitor at the 10% position. Compare the imaginary part of the equivalent impedance with the preset imaginary part impedance, and control the bypass state and series connection state of the second inductor through the second switch. When the second switch is closed, the second inductor is in the bypass state. When the second switch is open, the second inductor is in the series connection state.

[0066] S105. Calculate the reflection coefficient. The calculation method of the reflection coefficient is as follows:

[0067]

[0068] where Γ is the reflection coefficient, Z_current is the current equivalent impedance, and Zs is the equivalent impedance of the power supply, which is generally defaulted to 50Ω.

[0069] S106. Control the capacitance value of the adjustable capacitor until the reflection coefficient is less than the preset threshold. For example, the value range of the preset threshold is 0 - 0.02. Preferably, the preset threshold is 0.01. Compare the absolute value of the reflection coefficient with the preset threshold 0.01. By adjusting the capacitance values of the first adjustable capacitor and the second adjustable capacitor, the equivalent impedance in the matching network can be changed until the reflection coefficient calculated through the equivalent impedance is less than 0.01, and it can be determined that the matching network and the power supply are mutually matched.

[0070] It should be noted that the above settings for the first preset real part impedance, the second preset real part impedance, and the preset imaginary part impedance are preferred. The first preset real part impedance can be the real part impedance value corresponding to the second adjustable capacitor at the 10%-30% position. Specifically, the first preset real part impedance can be the real part impedance values corresponding to the second adjustable capacitor at positions such as 15%, 20%, 25%, 30%, etc. The second preset real part impedance is the real part impedance value corresponding to the second adjustable capacitor at the 70%-90% position. Specifically, the second preset real part impedance is the real part impedance values corresponding to the second adjustable capacitor at positions such as 70%, 75%, 80%, 85%, 90%, etc. The preset imaginary part impedance is the imaginary part impedance value corresponding to the first adjustable capacitor at the 10%-30% position. Specifically, the preset imaginary part impedance is the imaginary part impedance values corresponding to the first adjustable capacitor at positions such as 15%, 20%, 25%, 30%, etc.

[0071] In one or more embodiments, the step of controlling the bypass state and the series connection state of the first inductor based on the magnitude relationship between the real part of the equivalent impedance and the first preset real part impedance further includes: if the real part of the equivalent impedance is less than the first preset real part impedance, control the first inductor to be in the series connection state. For example, when the real part of the equivalent impedance is less than the first preset real part impedance, the first switch is turned off so that the first inductor is in the series connection state. If the real part of the equivalent impedance is greater than or equal to the first preset real part impedance, control the first inductor to be in the bypass state. For example, when the real part of the equivalent impedance is greater than or equal to the first preset real part impedance, the first switch is closed so that the first inductor is in the bypass state. In this way, by connecting the first inductor, the influence of parasitic parameters on the system stability is avoided when the adjustable capacitor is close to the edge position, and the matching speed is improved at the same time.

[0072] In one or more embodiments, the step of controlling the bypass state and the series connection state of the third inductor based on the magnitude relationship between the real part of the equivalent impedance and the second preset real part impedance further includes: if the real part of the equivalent impedance is greater than the second preset real part impedance, control the third inductor to be in the series connection state. For example, when the real part of the equivalent impedance is greater than the first preset real part impedance, the third switch is turned off so that the third inductor is in the series connection state. If the real part of the equivalent impedance is less than or equal to the second preset real part impedance, control the third inductor to be in the bypass state. For example, when the real part of the equivalent impedance is less than or equal to the first preset real part impedance, the third switch is closed so that the third inductor is in the bypass state.

[0073] In one or more embodiments, based on the magnitude relationship between the imaginary part of the equivalent impedance and the preset imaginary part impedance, the bypass state and the series connection state of the second inductor are controlled, which further includes: if the imaginary part of the equivalent impedance is less than the preset imaginary part impedance, the second inductor is controlled to be in the series connection state. For example, when the imaginary part of the equivalent impedance is less than the preset imaginary part impedance, the second switch is turned off so that the second inductor is in the series connection state. If the imaginary part of the equivalent impedance is greater than or equal to the preset imaginary part impedance, the second inductor is controlled to be in the bypass state. For example, when the imaginary part of the equivalent impedance is greater than or equal to the preset imaginary part impedance, the second switch is closed so that the second inductor is in the bypass state.

[0074] It should be noted that the first switch, the second switch, and the third switch are independently controlled. When the first switch is turned on, the second switch can be turned on or off. Different switches do not interfere with each other.

[0075] In one or more embodiments, the calculation method of the equivalent impedance includes:

[0076] When the first inductor, the second inductor, and the third inductor are all in the bypass state, the calculation method of the equivalent impedance is as follows:

[0077] Z0 = X C1 +X C2 / / R s

[0078]

[0079] where Z0 is the equivalent impedance when the first inductor, the second inductor, and the third inductor are all in the bypass state, X C2 is the reactance of the first adjustable capacitor, and X C1 is the reactance of the second adjustable capacitor.

[0080] When the first inductor is in the series connection state and the second inductor and the third inductor are both in the bypass state, the calculation method of the equivalent impedance is as follows:

[0081]

[0082]

[0083]

[0084]

[0085] where, is the equivalent impedance when the first inductor is in the series connection state and the second inductor and the third inductor are both in the bypass state, is the reactance of the first inductor.

[0086] It should be noted that connecting the first inductor L1 in series at the input end can make the proportion of the part with a larger real part in the equivalent impedance range of the overall matching network more; directly adding it to the imaginary part of the input impedance makes the overall imaginary part tend to be inductive.

[0087] When the second inductor is in the series connection state and the first inductor and the third inductor are both in the bypass state, the calculation method of the equivalent impedance is as follows:

[0088]

[0089]

[0090]

[0091]

[0092] Among them, is the equivalent impedance when the second inductor is in the series connection state and the first inductor and the third inductor are both in the bypass state, is the reactance of the second inductor.

[0093] It should be noted that if the load is capacitive, the inductive reactance of the second inductor L2 can partially or completely cancel the capacitive imaginary part, making the equivalent load close to a pure resistance. If the load is inductive, the second inductor L2 further enhances the inductive component of the imaginary part. At the same time, the phase delay introduced by the second inductor L2 can optimize the transmission efficiency.

[0094] When the third inductor is in the series connection state and the first inductor and the second inductor are both in the bypass state, the calculation method of the equivalent impedance is as follows:

[0095]

[0096]

[0097]

[0098]

[0099] is the equivalent impedance when the third inductor is in the series connection state and the first inductor and the second inductor are both in the bypass state, is the reactance of the third inductor.

[0100] It should be noted that on the parallel branch, a series resonance branch is formed after the third inductor L3 and the second adjustable capacitor C2 are connected in series, at the resonance frequency Nearby, the impedance of the branch approaches zero, causing the parallel branch to approximate a short circuit. At this time, the input impedance is mainly determined by the first adjustable capacitor C1 of the main path, and the real part is close to the equivalent series resistance of the first adjustable capacitor C1 and the load. When below the resonant frequency, the branch is capacitive, increasing the real part of the overall input impedance; when above the resonant frequency, the branch is inductive, which may reduce the real part. The influence on the imaginary part of the impedance is related to the operating frequency. When the operating frequency f < f0, the impedance of the parallel branch is capacitive, and the corresponding branch impedance is: The imaginary part is negative, that is, the overall is capacitive, canceling the inductive component on the series branch. When the operating frequency f > f0, the parallel branch is inductive The imaginary part is positive (inductive), enhancing the overall inductive imaginary part. By adjusting the second adjustable capacitor C2 and the third inductor L3, the sign and amplitude of the imaginary part can be flexibly controlled to cover a wide range of matching from capacitive to inductive. By flexibly combining the second adjustable capacitor C2, the first adjustable capacitor C1, and the inductor position, the L-type network can cover complex impedance regions to meet broadband, multi-frequency, or high-Q matching requirements.

[0101] In one or more embodiments, after the steps of obtaining the operating frequency and the equivalent impedance in the control method of the impedance matching device, it further includes:

[0102] Obtain the operating frequency of the power supply. For example, the operating frequency of the power supply can be the first preset operating frequency of 13.56 MHz and the second preset operating frequency of 27.12 MHz, and the frequency is detected by a frequency detection module on the circuit. It is more reliable and convenient compared to manual input.

[0103] Determine whether the current operating frequency is the first preset operating frequency or the second preset operating frequency. For example, when the operating frequency is between 13.56 MHz ± 5%, that is, between 12.88 MHz and 14.24 MHz, it can be determined that the operating frequency is the first preset operating frequency of 13.56 MHz. When the operating frequency is between 27.12 MHz ± 5%, that is, between 25.76 MHz and 28.48 MHz, it can be determined that the operating frequency is the second preset operating frequency of 27.12 MHz.

[0104] When the operating frequency is the first preset operating frequency, directly control the capacitance value of the adjustable capacitor until the reflection coefficient is less than the preset threshold. Specifically, the method of adjusting the capacitance value of the adjustable capacitor to make the reflection coefficient match is the prior art and will not be elaborated here. When the operating frequency is the second preset operating frequency, based on the set conditions, control the bypass state and the series connection state of the first inductor, the second inductor, and the third inductor.

[0105] Such as Figure 7As shown, taking the working frequency of 27.12 MHz, the value of the first adjustable vacuum capacitor C1 being 50 pF - 500 pF, and the value of the second adjustable vacuum capacitor C2 being 100 pF - 1000 pF as an example. Through calculation, it can be known that Figure 7 The purple above is the state matching range when no inductor is connected; the matching range when the first inductor L1 is connected in the circuit; the green is the matching range when the third inductor L3 is connected in the circuit; the brown is the matching range when the second inductor L2 is connected in the circuit. From the ranges in the figure, it can be seen that when the same first adjustable capacitor and second adjustable capacitor are used, different inductors are connected, and the matching ranges of the circuit are different. This makes the matching position located near the center best matching point.

[0106] As Figure 6 shown, the flow of the control method of the impedance matching device according to an embodiment of the present invention includes the following steps:

[0107] S701, obtain the working frequency of the power supply;

[0108] S702, obtain the equivalent impedance of the matching network;

[0109] S703, determine whether the current working frequency is equal to the first preset working frequency or the second preset working frequency; if it is equal to the first working frequency, then execute S705, if it is equal to the second preset working frequency, then execute S709, S710, and S711;

[0110] S705, calculate the reflection coefficient;

[0111] S706, determine whether the reflection coefficient is less than the preset threshold; if so, then execute S707, if not, then execute S708;

[0112] S707, maintain the current matching network;

[0113] S708, adjust the first adjustable capacitor and the second adjustable capacitor, and execute S702 again;

[0114] S709, determine whether the real part R_current of the equivalent impedance is less than the first preset real part impedance; if so, then execute to disconnect the first switch; if not, then execute to close the first switch;

[0115] S710, determine whether the real part R_current of the equivalent impedance is greater than the second preset real part impedance; if so, then execute to disconnect the third switch; if not, then execute to close the third switch;

[0116] S711, determine whether the imaginary part X_current of the equivalent impedance is less than the preset imaginary part impedance; if so, then execute to disconnect the second switch; if not, then execute to close the second switch;

[0117] At S704, recalculate the equivalent impedance and execute S705 again.

[0118] Those skilled in the art can understand that although some embodiments herein include certain features included in other embodiments rather than other features, the combination of features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the claims of the present application, any one of the claimed embodiments can be used in any combination.

[0119] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. An impedance matching device, which is connected between a power supply and a load and includes a matching network, characterized in that, The matching network includes a series branch, a parallel branch, and a control component; The series branch connects the power supply and the load in series, and a first inductor, a first adjustable capacitor, and a second inductor are connected in series on the series branch; Both ends of the parallel branch are connected to the series branch, the parallel branch is connected in parallel with the first adjustable capacitor, the second inductor, and the load, and a second adjustable capacitor and a third inductor are provided on the parallel branch; The control component is controllably connected to the first inductor, the second inductor, and the third inductor, and the control component is configured to be able to separately control each inductor to be in a bypass state.

2. The impedance matching device according to claim 1, characterized in that The control component includes a first switch, a second switch, and a third switch. The first switch is arranged in parallel with the first inductor and is configured to be able to make the first inductor in a bypass state when the first switch is in a closed state; The second switch is arranged in parallel with the second inductor and is configured to be able to make the second inductor in a bypass state when the second switch is in a closed state; the third switch is arranged in parallel with the third inductor and is configured to be able to make the third inductor in a bypass state when the third switch is in a closed state.

3. The impedance matching device according to claim 1, characterized in that The impedance matching device further includes a frequency detection module, an impedance detection module, a motor control module, and a switch control module. The frequency detection module is configured to be able to detect the operating frequency of the power supply; the impedance detection module is configured to be able to detect and calculate the equivalent impedance of the matching network; The motor control module is configured to be able to control the capacitance values of the first adjustable capacitor and the second adjustable capacitor; the switch control module is configured to be able to control the opening and closing of the first switch, the second switch, and the third switch.

4. A control method for an impedance matching device, the impedance matching device being the device according to any one of claims 1-3, characterized in that, The control method of the impedance matching device includes: Obtaining the operating frequency of the power supply and the equivalent impedance of the matching network; Based on the magnitude relationship between the real part of the equivalent impedance and a first preset real part impedance, controlling the bypass state and the series connection state of the first inductor; Based on the magnitude relationship between the real part of the equivalent impedance and a second preset real part impedance, controlling the bypass state and the series connection state of the third inductor; Based on the magnitude relationship between the imaginary part of the equivalent impedance and a preset imaginary part impedance, controlling the bypass state and the series connection state of the second inductor; Calculating the reflection coefficient; Controlling the capacitance value of the adjustable capacitor until the reflection coefficient is less than a preset threshold; Wherein, the first preset real part impedance is the real part impedance value corresponding to the second adjustable capacitor at the 10%-30% position; the second preset real part impedance is the real part impedance value corresponding to the second adjustable capacitor at the 70%-90% position; the preset imaginary part impedance is the imaginary part impedance value corresponding to the first adjustable capacitor at the 10%-30% position.

5. The control method of the impedance matching device according to claim 4, characterized in that, The step of controlling the bypass state and the series connection state of the first inductor based on the magnitude relationship between the real part of the equivalent impedance and the first preset real part impedance further includes: If the real part of the equivalent impedance is less than the first preset real part impedance, controlling the first inductor to be in a series connection state; If the real part of the equivalent impedance is greater than or equal to the first preset real part impedance, controlling the first inductor to be in a bypass state.

6. The control method of the impedance matching device according to claim 5, characterized in that, Based on the magnitude relationship between the real part of the equivalent impedance and the second preset real part impedance, controlling the bypass state and the series connection state of the third inductor further includes: If the real part of the equivalent impedance is greater than the second preset real part impedance, control the third inductor to be in the series connection state; If the real part of the equivalent impedance is less than or equal to the second preset real part impedance, control the third inductor to be in the bypass state.

7. The control method of the impedance matching device according to claim 6, characterized in that, Based on the magnitude relationship between the imaginary part of the equivalent impedance and the preset imaginary part impedance, controlling the bypass state and the series connection state of the second inductor further includes: If the imaginary part of the equivalent impedance is less than the preset imaginary part impedance, control the second inductor to be in the series connection state; If the imaginary part of the equivalent impedance is greater than or equal to the preset imaginary part impedance, control the second inductor to be in the bypass state.

8. The control method of the impedance matching device according to claim 7, characterized in that, The calculation method of the equivalent impedance includes: When the first inductor, the second inductor, and the third inductor are all in the bypass state, the calculation method of the equivalent impedance is as follows: Z0 = X C1 +X C2 / / R s When the first inductor is in the series connection state, and the second inductor and the third inductor are both in the bypass state, the calculation method of the equivalent impedance is as follows: When the second inductor is in the series connection state, and the first inductor and the third inductor are both in the bypass state, the calculation method of the equivalent impedance is as follows: When the third inductor is in the series connection state, and the first inductor and the second inductor are both in the bypass state, the calculation method of the equivalent impedance is as follows: Among them, Z0 is the equivalent impedance when the first inductor, the second inductor, and the third inductor are all in the bypass state, X C1 is the reactance of the first adjustable capacitor, X C2 is the reactance of the second adjustable capacitor, R s is the internal resistance of the RF power supply; is the equivalent impedance when the first inductor is in the series connection state and the second inductor and the third inductor are both in the bypass state, is the reactance of the first inductor, is the equivalent impedance when the second inductor is in the series connection state and the first inductor and the third inductor are both in the bypass state, is the reactance of the second inductor, is the equivalent impedance when the third inductor is in the series connection state and the first inductor and the second inductor are both in the bypass state, is the reactance of the third inductor.

9. The control method of the impedance matching device according to claim 3, characterized in that, In the control method of the impedance matching device, after the steps of obtaining the operating frequency and the equivalent impedance, it further includes: Obtain the operating frequency of the power supply; Judge whether the current operating frequency is the first preset operating frequency or the second preset operating frequency; When the operating frequency is the first preset operating frequency, directly control the capacitance value of the adjustable capacitor until the reflection coefficient is less than the preset threshold; when the operating frequency is the second preset operating frequency, based on the set conditions, control the bypass state and the series connection state of the first inductor, the second inductor, and the third inductor.

10. The control method of the impedance matching device according to claim 4, characterized in that, The calculation method of the reflection coefficient is as follows: Where Γ is the reflection coefficient, Z_current is the current equivalent impedance, and Zs is the equivalent impedance of the power supply.

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