Flow regulating device, mass flow controller and flow control method thereof

Abstract

The application provides a flow regulating device, a mass flow controller and a flow control method thereof. The flow regulating device comprises: a flow regulating component having an inlet hole and an outlet hole; a connecting piece movably arranged along an axis thereof, the connecting piece being in driving cooperation with the flow regulating component; a piezoelectric driver for driving the connecting piece to move along the axis direction; and a limiting piece connected between the piezoelectric driver and the connecting piece, the limiting piece being used for applying a pre-tightening force within a preset range to the piezoelectric driver along the axis direction of the connecting piece. The flow regulating device of the application is provided with the limiting piece, and the limiting piece is connected between the piezoelectric driver and the connecting piece, which is equivalent to that the connecting piece applies the pre-tightening force to the piezoelectric driver through the limiting piece, so that the influence of voltage ripple of the driving voltage on the piezoelectric driver is reduced.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and more specifically, to a flow regulating device, a mass flow controller, and a flow control method thereof. Background Technology

[0002] Pressure-type gas mass flow controllers have advantages such as high control accuracy and fast response speed, and are currently widely used in semiconductor equipment. However, with the development of semiconductor technology, high-end advanced process equipment has increasingly higher requirements for the accuracy of process gas flow, which places higher precision requirements on the gas flow control components.

[0003] In some related technologies, mass flow controllers use piezoelectric actuators to regulate the flow rate of fluid in a pipeline. During operation, the piezoelectric actuator extends according to the input voltage, thereby regulating the fluid flow rate. However, due to voltage ripple in the voltage used to drive the piezoelectric actuator, the actuator contracts and stretches with the voltage ripple, causing changes in the opening degree of the mass flow controller and resulting in unstable flow. Summary of the Invention

[0004] The present invention aims to at least solve the problem in the prior art where the piezoelectric actuator expands and contracts with voltage ripple, causing the opening degree of the mass flow controller to change and resulting in unstable flow. The present invention proposes a flow regulating device, a mass flow controller and a flow control method thereof.

[0005] To achieve the objectives of this invention, a flow regulating device is provided, comprising: a flow regulating component having an inlet orifice and an outlet orifice, the flow regulating component being used to regulate the flow rate of fluid from the inlet orifice to the outlet orifice; a connector movably disposed along its own axis, the connector being driven to cooperate with the flow regulating component so that the flow regulating component regulates the flow rate of fluid from the inlet orifice to the outlet orifice; a piezoelectric actuator for extending under the action of a driving voltage to drive the connector to move along the axial direction; and a limiting member connected between the piezoelectric actuator and the connector, the limiting member being used to apply a preload force within a preset range to the piezoelectric actuator along the axial direction of the connector to limit the length change of the piezoelectric actuator caused by voltage fluctuations within the preset range.

[0006] Optionally, the connector has a first end and a second end along its axial direction, the first end of the connector being away from the flow regulating component, and the second end of the connector being close to the flow regulating component;

[0007] The connector has an internal mounting cavity, and both the piezoelectric actuator and the limiting member are located within the mounting cavity. The limiting member is connected to the inner wall of the connector and is located between at least one end of the connector and the piezoelectric actuator.

[0008] Optionally, a first elastic element is connected to the inner wall of the connector, the first elastic element is located between the second end of the connector and the piezoelectric actuator, the piezoelectric actuator abuts against the first elastic element, and the first elastic element is used to apply the preload force toward the first end of the connector.

[0009] Optionally, a second elastic element is located between the first end of the connector and the piezoelectric actuator, the piezoelectric actuator abutting against the second elastic element, the second elastic element being used to apply the preload towards the second end of the connector.

[0010] Optionally, the flow regulating device further includes: a support block, fixedly connected to the flow regulating component, the support block passing through the connector, the connector being axially movable relative to the support block, the first elastic element being located between the piezoelectric actuator and the support block, and the piezoelectric actuator contacting the support block through the first elastic element.

[0011] Optionally, the first elastic member includes: a sheet-like portion having a first side facing the piezoelectric actuator and a second side facing the support block, the sheet-like portion being connected to the inner wall of the connector; and a protrusion disposed on the second side of the sheet-like portion for contacting the support block.

[0012] Optionally, the flow regulating device further includes a self-aligning ball disposed between the first elastic element and the piezoelectric actuator, wherein the piezoelectric actuator abuts against the first elastic element through the self-aligning ball.

[0013] Optionally, a first limiting hole is provided on the first side of the sheet-like portion, and the side of the self-aligning ball facing the first elastic element is located in the first limiting hole and is limited and engaged; the piezoelectric actuator is provided with a second limiting hole corresponding to the self-aligning ball, and the side of the self-aligning ball facing the piezoelectric actuator is located in the second limiting hole and is limited and engaged.

[0014] Optionally, the range of the preload F of the first elastic element is (F m / V m )×(V x / 2)-A≤F≤(F m / V m )×(V x / 2)+A, where F m V is the maximum output driving force of the piezoelectric actuator.m V is the driving voltage required for the piezoelectric actuator to output maximum driving force. x Let A be the peak-to-peak value of the driving voltage, and let A be a constant.

[0015] Optionally, the range of values ​​for A is F. m 1%-10%.

[0016] According to a second aspect of the present invention, a mass flow controller is also disclosed, comprising: the flow regulating device described above; an input channel connected to the inlet of the flow regulating device, wherein the fluid flows into the mass flow controller from the input channel; an output channel connected to the outlet of the flow regulating device, wherein the fluid flows out of the mass flow controller from the output channel; a flow detection component for detecting the flow rate of the fluid flowing through the input channel and the output channel; and a control module for controlling the piezoelectric actuator to drive the connector to move based on the detection results of the flow rate of the fluid flowing through the input channel and the output channel, so that the flow rate of the fluid output from the output channel reaches a preset flow rate value.

[0017] Optionally, the control module includes: a drive circuit module electrically connected to the piezoelectric actuator, used to provide a drive voltage to the piezoelectric actuator to adjust the length of the piezoelectric actuator; a voltage acquisition module electrically connected to the drive circuit module, used to acquire the drive voltage value of the drive circuit module; the control module is used to acquire the current drive voltage value when the difference between the actual flow value output by the output channel and the preset flow value is less than or equal to a preset range, and to calculate the preset voltage value of the drive circuit at the next moment based on the current preset voltage value of the drive circuit module, the current preset flow value, and the actual flow value.

[0018] Optionally, the control module calculates the preset voltage value V of the drive circuit module at the next moment according to the following formula. s(i+1) :

[0019] V s(i+1) =K1V mi 2 +K2V mi +K3V xi +K4(F fi -F si )+K5,

[0020] Among them, V xi V represents the current drive voltage value of the drive circuit module. mi F is the current preset voltage value of the drive circuit module. si F is the preset flow rate value output by the output channel. fiK1, K2, K3, K4, and K5 are the actual flow rate values ​​output by the output channel, and K1, K2, K3, K4, and K5 are fixed constants.

[0021] Optionally, the drive circuit module includes a fast start circuit electrically connected to the piezoelectric actuator. The fast start circuit is used to provide a start voltage to the piezoelectric actuator when the flow regulating device is turned on, so that the piezoelectric actuator can overcome the preload force.

[0022] Optionally, the starting voltage value V1 provided by the fast start circuit can range from V... x -B≤V1≤V x +B, where V x Let be the peak-to-peak value of the voltage ripple, and B be a constant.

[0023] Optionally, the value of B is in the range of 1% to 10% of the highest driving voltage value of the piezoelectric actuator.

[0024] According to a third aspect of the present invention, a flow control method for a mass flow controller is also disclosed. The flow control method is applied to the mass flow controller described above. The flow control method includes: when the difference between the actual flow value output by the output channel and the preset flow value is less than a preset range, obtaining the current driving voltage value; obtaining the current preset voltage value, the current preset flow value, and the actual flow value of the driving circuit module; and calculating the preset voltage value of the driving circuit at the next moment based on the current preset voltage value, the current preset flow value, and the actual flow value of the driving circuit module.

[0025] Optionally, calculating the preset voltage value of the drive circuit at the next moment based on the current preset voltage value of the drive circuit module, the current preset flow rate value, and the actual flow rate value specifically includes:

[0026] The preset voltage value V of the drive circuit module at the next moment is obtained according to the following formula. s(i+1) :

[0027] V s(i+1) =K1V mi 2 +K2V mi +K3V xi +K4(F fi -F si )+K5,

[0028] Among them, V xi V represents the current drive voltage value of the drive circuit module. mi F is the current preset voltage value of the drive circuit module. si F is the preset flow rate value output by the output channel.fi K1, K2, K3, K4, and K5 are the actual flow rate values ​​output by the output channel, and K1, K2, K3, K4, and K5 are fixed constants.

[0029] The flow regulating device of the present invention, by setting a limiting member and connecting the limiting member between the piezoelectric actuator and the connecting member, is equivalent to the connecting member applying a preload to the piezoelectric actuator through the limiting member, thereby reducing the impact of the voltage ripple of the driving voltage on the voltage actuator. Moreover, since the preload is not applied to the piezoelectric actuator by a spring, the original spring parameters and the parameters of the piezoelectric actuator itself can remain unchanged, ensuring the accuracy of subsequent flow control. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a flow regulating device in related technologies;

[0031] Figure 2 This is a schematic diagram of the flow regulating device according to an embodiment of the present invention;

[0032] Figure 3 This is an exploded view of the flow regulating device according to an embodiment of the present invention;

[0033] Figure 4 This is a perspective view of the first elastic element of the flow regulating device according to an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the structure of the first elastic element of the flow regulating device according to an embodiment of the present invention;

[0035] Figure 6 This is an assembly diagram of the first elastic element of the flow regulating device according to an embodiment of the present invention;

[0036] Figure 7 This is a schematic diagram of the force applied to the piezoelectric actuator of the flow regulating device according to an embodiment of the present invention;

[0037] Figure 8 This is a schematic diagram illustrating the principle of the flow regulation device applied to a mass flow controller according to an embodiment of the present invention;

[0038] Figure 9 This is a schematic diagram of the drive circuit module of the mass flow controller according to an embodiment of the present invention;

[0039] Figure 10 This is a schematic diagram of the fast start-up circuit of the mass flow controller according to an embodiment of the present invention;

[0040] Figure 11 This is a schematic diagram of the preset voltage module of the mass flow controller according to an embodiment of the present invention;

[0041] Figure 12This is a schematic diagram of the preset voltage module of a mass flow controller according to another embodiment of the present invention;

[0042] List of reference numerals in the attached diagram:

[0043] 10. Flow regulating assembly; 11. Mounting base; 12. Valve port component; 121. Inlet hole;

[0044] 122. Outlet hole; 13. Valve core push rod seat; 131. Third through hole; 14. Valve core push rod; 15. Elastic diaphragm; 20. Connector; 21. Connecting sleeve; 211. First through hole; 212. Second through hole; 22. Top encapsulation; 23. Mounting cavity; 24. Bottom encapsulation; 30. Piezoelectric actuator; 40. First elastic element; 41. Sheet-like portion; 411. First limiting hole; 412. Connecting end; 42. Protrusion; 50. Second elastic element 60. Support block; 70. Spring; 80. Self-aligning ball; 91. Input channel; 92. Output channel; 94. Control module; 941. Drive circuit module; 9411. Fast start circuit; 94111. Constant current source module; 94112. Preset voltage module; 9412. Boost circuit; 942. Voltage acquisition module; 943. Microcontroller unit; 95. Current limiting element; 96. First sensor; 97. Second sensor; 98. Third sensor;

[0045] Q1, first transistor; Q2, second transistor; Q3, third transistor; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor. Detailed Implementation

[0046] To enable those skilled in the art to better understand the technical solutions of the present invention, the flow regulating device, mass flow controller and flow control method provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0047] Pressure-type gas mass flow controllers have advantages such as high control accuracy and fast response speed, and are currently widely used in semiconductor equipment. However, with the development of semiconductor technology, high-end advanced process equipment has increasingly higher requirements for the accuracy of process gas flow, which places higher precision requirements on the gas flow control components.

[0048] In some related technologies, mass flow controllers regulate the fluid flow rate in pipelines using flow regulation devices. Specifically, for example... Figure 1 As shown, the flow regulating device includes: a top encapsulation component 1a, a connecting sleeve 2a, a piezoelectric actuator 3a, a support block 4a, a spring 5a, and a flow regulating assembly 6a.

[0049] A top encapsulation component 1a is mounted on top of the connecting sleeve 2a for fixing the piezoelectric actuator 3a. The connecting sleeve 2a has a first through hole 21a and a second through hole 22a respectively penetrating the sidewall, and the first through hole 21a and the second through hole 22a are arranged opposite to each other. A support block 4a passes through the first through hole 21a and the second through hole 22a, dividing the inner cavity of the connecting sleeve 2a into an upper cavity and a lower cavity. In the axial direction of the connecting sleeve 2a, the support block 4a slides with the first through hole 21a and the second through hole 22a respectively, and the support block 4a is fixedly connected to the flow regulating component 6a.

[0050] The piezoelectric actuator 3a is installed in the upper cavity of the connecting sleeve 2a. The bottom end of the piezoelectric actuator 3a contacts the support block 4a, and the top end mates with the top encapsulation component 1a. The bottom of the lower cavity of the connecting sleeve 2a is a sealed bottom surface. The spring 5a is installed in the lower cavity. The two ends of the spring 5a press against the sealed bottom surface and the support block 4a respectively. During operation, the spring 5a is in a compressed state.

[0051] The flow regulating assembly 6a includes: a fixed base 61a, a channel component 62a, a valve port component 63a, a valve core push rod seat 64a, a valve core push rod 65a, and an elastic diaphragm 66a.

[0052] The fixing seat 61a is set on the top of the channel component 62a, and the support block 4a is fixedly connected to the top of the fixing seat 61a by bolts. The fixing seat 61a is provided with a first through hole 21a in the vertical direction, and the connecting sleeve 2a is movably set in the first through hole 21a.

[0053] The channel component 62a is provided with a mounting groove 621a, which is located below the first through hole 21a. The channel component 62a has an air inlet channel 622a and an air outlet channel 623a, both of which are connected to the mounting groove 621a. The valve port component 63a is located within the mounting groove 621a. The valve port component 63a has an air inlet hole 631a and an air outlet hole 632a, which are connected to the air inlet channel 622a and the air outlet hole 632a, respectively. Gas flows from the air inlet channel 622a through the air inlet hole 631a and the air outlet hole 632a to the air outlet channel 623a.

[0054] The valve core push rod seat 64a is disposed between the fixed seat 61a and the channel component 62a. A third through hole 641a is provided in the valve core push rod seat 64a. The third through hole 641a passes through the valve core push rod seat 64a in the vertical direction and connects the first through hole 21a and the mounting groove 621a.

[0055] A valve core push rod 65a is disposed in the third through hole 641a. One end of the valve core push rod 65a is opposite to the air inlet 631a, and the other end of the valve core push rod 65a abuts against the bottom surface of the connecting sleeve 2a. An elastic diaphragm 66a is annular. The inner ring edge of the elastic diaphragm 66a is connected to the outer peripheral wall of the valve core push rod 65a, and the outer ring edge of the elastic diaphragm 66a is connected to the wall of the third through hole 641a. The elastic diaphragm 66a can undergo elastic deformation when the valve core push rod 65a moves downward, thereby achieving the reset of the valve core push rod 65a.

[0056] When the piezoelectric actuator 3a of the flow regulating device is de-energized, under the action of the spring 5a, the sealing surface at the bottom of the elastic diaphragm 66a blocks the air inlet 631a and the air outlet 632a, and the air inlet channel 622a and the air outlet channel 623a are no longer connected, blocking the gas passage, and the valve is closed. When the flow regulating device receives the set flow signal, it opens to the corresponding degree. Specifically, the piezoelectric actuator 3a generates a corresponding extension ΔX according to the applied voltage. After the piezoelectric actuator 3a extends, it drives the top encapsulation component 1a and the connecting sleeve 2a to move upward by a displacement of ΔX. At this time, the spring 5a is compressed by ΔX. The valve core push rod 65a moves upward by a displacement of ΔX under the reset action of the elastic diaphragm 66a. At this time, the sealing surface at the bottom of the elastic diaphragm 66a and the air inlet 631a and the air outlet 632a generate a displacement of ΔX, and the air inlet channel 622a and the air outlet channel 623a are connected, and the fluid passes through the flow regulating device and flows through the set flow rate. By applying different voltages to the flow regulating device, different opening degrees are generated, and different flow rates are obtained.

[0057] However, since the input voltage of a gas mass flow controller is generally 24V or ±15V, in order to generate a 150V piezoelectric ceramic driving voltage, the input voltage needs to be boosted in the circuit. The boost circuit is generally used to increase the voltage. However, since there is voltage ripple in the voltage used to drive the piezoelectric actuator 3a, the piezoelectric actuator 3a contracts and stretches with the voltage ripple, causing the opening of the mass flow controller to change, resulting in unstable flow.

[0058] Existing voltage actuators are composed of multiple stacked piezoelectric ceramic sheets. Research has found that the magnitude of the compressive force between adjacent piezoelectric ceramic sheets affects the extent of contraction and stretching of the piezoelectric actuator 3a with voltage ripple. In other words, the greater the compressive force between adjacent piezoelectric ceramic sheets, the smaller the extent of contraction and stretching of the piezoelectric actuator 3a with voltage ripple, and therefore the less affected it is by voltage ripple, and vice versa.

[0059] Based on this finding, combined with Figure 1As can be seen from the structure, the piezoelectric actuator 3a is subjected to pressure from the spring 5a. Therefore, those skilled in the art would typically increase the pressure received by the piezoelectric actuator 3a by increasing the elastic force of the spring 5a, according to Hooke's Law F = -kx, where F is the force exerted by the spring 5a on the object, x is the change in length of the spring 5a, and k is the elastic coefficient. In other words, to increase the pressure exerted by the spring 5a on the piezoelectric actuator 3a, it is necessary to increase the compression or elastic coefficient of the spring 5a. However, in existing flow control devices, the parameters of the piezoelectric actuator 3a and the spring 5a are matched. When the elastic coefficient or length of the spring 5a changes, it will inevitably affect the subsequent flow control accuracy. Therefore, how to increase the pressure received by the piezoelectric actuator 3a without changing the parameters of the spring 5a is a problem that urgently needs to be solved in this field.

[0060] In order to solve the problem, such as Figures 2 to 3 As shown, a flow regulating device is disclosed, comprising: a flow regulating assembly 10, a connector 20, a piezoelectric actuator 30, and a limiting member. The flow regulating assembly 10 has an inlet hole 121 and an outlet hole 122, and is used to regulate the flow rate of fluid from the inlet hole 121 to the outlet hole 122. The connector 20 is movably disposed along its own axis, and the connector 20 drives the flow regulating assembly 10 to regulate the flow rate of fluid from the inlet hole 121 to the outlet hole 122. The piezoelectric actuator 30 is used to extend under the action of a driving voltage to drive the connector 20 to move along the axial direction. The limiting member is connected between the piezoelectric actuator 30 and the connector 20, and is used to apply a preload force within a preset range to the piezoelectric actuator 30 along the axial direction of the connector 20 to limit the length change of the piezoelectric actuator 30 caused by voltage fluctuations within the preset range.

[0061] In use, the limiting member is connected between the piezoelectric actuator 30 and the connector 20. Therefore, a preload can be applied to the piezoelectric actuator 30 through the limiting member, making the adjacent piezoelectric ceramic sheets fit more tightly, thereby reducing the impact of the driving voltage ripple on the voltage actuator. Moreover, since the limiting member is connected to the connector 20, when the limiting member applies a preload to the piezoelectric actuator 30, the reaction force on the limiting member is ultimately transmitted to the connector 20. In other words, it is equivalent to the connector 20 applying a preload to the piezoelectric actuator 30 through the limiting member, thus not affecting the spring 70.

[0062] The flow regulating device of the present invention, by setting a limiting member and connecting the limiting member between the piezoelectric actuator 30 and the connecting member 20, is equivalent to the connecting member 20 applying a preload to the piezoelectric actuator 30 through the limiting member, thereby reducing the impact of the driving voltage ripple on the voltage actuator. Moreover, since the preload is not applied to the piezoelectric actuator 30 by the spring 70, the original parameters of the spring 70 and the parameters of the piezoelectric actuator itself can remain unchanged, ensuring the accuracy of subsequent flow control.

[0063] like Figure 2 As shown, the connector 20 has a first end and a second end along its axial direction. The first end of the connector 20 is away from the flow regulating assembly 10, and the second end of the connector 20 is close to the flow regulating assembly 10. The connector 20 has a mounting cavity 23 inside, and the piezoelectric actuator 30 and the limiting member are both located in the mounting cavity 23. The limiting member is connected to the inner wall of the connector 20 and is located between at least one end of the connector 20 and the piezoelectric actuator 30.

[0064] In some embodiments, the mounting cavity 23 extends axially along the connector 20, and the limiting member can be disposed between the first end of the connector 20 and the piezoelectric actuator 30. In this case, the direction of the preload applied by the limiting member is towards the second end of the connector 20. In other embodiments, the limiting member can also be disposed between the second end of the connector 20 and the piezoelectric actuator 30. In this case, the direction of the preload applied by the limiting member is towards the first end of the connector 20. Figure 2 and Figure 3 In the embodiment shown, there may be two limiting members, which are simultaneously disposed between the first end of the connector 20 and the piezoelectric actuator 30 and between the second end of the connector 20 and the piezoelectric actuator 30, while the directions of the preload are opposite.

[0065] For example, such as Figure 2 and Figure 3 As shown, the limiting member includes a first elastic element 40 and a second elastic element 50. The first elastic element 40 is connected to the inner wall of the connector 20 and is located between the second end of the connector 20 and the piezoelectric actuator 30. The piezoelectric actuator abuts against the first elastic element 40, and the first elastic element 40 is used to apply a preload force toward the first end of the connector 20. The second elastic element 50 is located between the first end of the connector 20 and the piezoelectric actuator 30, and the piezoelectric actuator abuts against the second elastic element 50. The second elastic element 50 is used to apply a preload force toward the second end of the connector 20. By setting the first elastic element 40 and the second elastic element 50, a preload force is applied to the piezoelectric actuator 30, increasing the compressive force between adjacent piezoelectric ceramic sheets, reducing the amplitude of contraction and stretching of the piezoelectric actuator 30 due to voltage ripple, and reducing the impact of voltage ripple.

[0066] like Figure 2 and Figure 3 As shown, the connector 20 includes a connecting sleeve 21, a top encapsulation 22, and a bottom encapsulation 24. The connecting sleeve 21 has a first end and a second end axially. The top encapsulation 22 is detachably connected to the first end of the connecting sleeve 21 for fixing the piezoelectric actuator 30, thereby forming the first end of the connector 20. The bottom encapsulation 24 is connected to the second end of the connecting sleeve 21, thereby forming the second end of the connector 20. That is, the interior of the connecting sleeve 21, together with the top encapsulation 22 and the bottom encapsulation 24, forms a mounting cavity 23.

[0067] It is understood that the voltage actuator is composed of multiple piezoelectric ceramic sheets stacked together. In this embodiment, the multiple piezoelectric ceramic sheets in the voltage actuator are stacked along the axial direction of the connecting sleeve 21. Therefore, the voltage actuator has a first end and a second end along the axial direction of the connecting sleeve 21. The first end of the piezoelectric actuator 30 faces the top encapsulation 22, and the second end of the piezoelectric actuator 30 faces the bottom encapsulation 24. The first elastic member 40 is connected to the inner peripheral wall of the connecting sleeve 21 and abuts against the second end of the piezoelectric actuator 30, that is, the end of the piezoelectric actuator 30 closest to the second end of the connecting member 20, thereby applying a preload force to the piezoelectric actuator 30, increasing the compressive force of the adjacent piezoelectric ceramic sheets, reducing the amplitude of contraction and stretching of the piezoelectric actuator 30 with voltage ripple, and reducing the impact of voltage ripple.

[0068] In this embodiment, the second elastic member 50 is disposed between the first end of the connector 20 and the first end of the piezoelectric actuator 30, and the piezoelectric actuator 30 abuts against the inner wall of the first end of the connector 20 through the second elastic member 50. That is, as... Figure 2 and Figure 3 As shown, the second elastic element 50 is disposed between the first end of the piezoelectric actuator 30 and the top package 22. The first end of the piezoelectric actuator 30 abuts against the top package 22 through the second elastic element 50, thereby buffering the expansion and contraction of the piezoelectric actuator 30 due to voltage ripple within a certain range. This reduces the impact of voltage ripple and also reduces the risk of damage caused by hard contact between the piezoelectric actuator 30 and the top package 22. For example, the second elastic element 50 is an annular spring.

[0069] like Figure 2 and Figure 3 As shown, the flow regulating device also includes a support block 60 and a spring 70. The support block 60 is fixedly connected to the flow regulating assembly 10. The support block 60 passes through the connector 20 and is perpendicular to the connector 20. The connector 20 is axially movable relative to the support block 60. The first elastic element 40 is located between the piezoelectric actuator 30 and the support block 60. The piezoelectric actuator 30 contacts the support block 60 through the first elastic element 40.

[0070] For example, such as Figure 2 and Figure 3 As shown, the connecting sleeve 21 has a first through hole 211 and a second through hole 212 that penetrate the sidewall, respectively, and the first through hole 211 and the second through hole 212 are arranged opposite to each other. The support block 60 passes through the first through hole 211 and the second through hole 212. Axially, the support block 60 slides with the first through hole 211 and the second through hole 212, respectively, and the support block 60 is fixedly connected to the flow regulating assembly 10. Figure 2 The piezoelectric actuator 30 is located between the support block 60 and the top encapsulation 22. The first elastic element 40 is located between the second end of the piezoelectric actuator 30 and the support block 60, and the second end of the piezoelectric actuator 30 contacts the support block 60 through the first elastic element 40. The spring 70 is disposed between the support block 60 and the second end of the connecting sleeve 21, and the two ends of the spring 70 abut against the bottom encapsulation 24 of the support block 60 and the second end of the connecting sleeve 21, respectively.

[0071] Specifically, such as Figure 4 and Figure 5 As shown, the first elastic element 40 includes a sheet-like portion 41 and a protrusion 42. The sheet-like portion 41 has a first side facing the piezoelectric actuator 30 and a second side facing the support block 60. The sheet-like portion 41 has two connecting ends 412 in the length direction, both of which are connected to the inner wall of the connecting sleeve 21. The protrusion 42 is disposed on the second side of the sheet-like portion 41 for contacting the support block 60. By connecting the two connecting ends 412 of the sheet-like portion 41 to the inner wall of the connecting sleeve 21, when the second end of the piezoelectric actuator 30 abuts against the first side of the sheet-like portion 41, the sheet-like portion 41 generates elastic force through deformation, thereby applying a preload force to the piezoelectric actuator 30. Since both ends of the sheet-like portion 41 are connected to the inner wall of the connecting sleeve 21, that is, the inner wall of the connecting sleeve 21, the reaction force of the sheet-like portion 41 acts on the connecting sleeve 21, and therefore does not affect the spring 70. By setting the protrusion 42, when the flow rate needs to be adjusted, the piezoelectric actuator 30 can abut against the support block 60 through the protrusion 42. Since the piezoelectric actuator 30 is always in contact with the support block 60 through the protrusion 42, the protrusion 42 will not be affected by the deformation of the piezoelectric ceramic sheet, which can ensure the consistency of the contact position between the protrusion 42 and the support block 60, thereby improving the stability of flow control.

[0072] like Figure 2 and Figure 3 As shown, the flow regulating device further includes a self-aligning ball 80. The self-aligning ball 80 is disposed between the first elastic element 40 and the piezoelectric actuator 30, and the piezoelectric actuator 30 abuts against the first elastic element 40 through the self-aligning ball 80. By setting the self-aligning ball 80, the piezoelectric actuator 30 abuts against the first elastic element 40 through the self-aligning ball 80, which can avoid the inconsistency of the contact position between the piezoelectric ceramic sheet and the first elastic element 40 after deformation, thus avoiding the inconsistency of the force position of the first elastic element 40.

[0073] like Figure 5 and Figure 6 As shown, exemplarily, a first limiting hole 411 is provided on the first side of the sheet-like portion 41. The side of the self-aligning ball 80 facing the first elastic member 40 is located within the first limiting hole 411 and is limited and engaged. The piezoelectric actuator 30 is provided with a second limiting hole corresponding to the self-aligning ball 80. The side of the self-aligning ball 80 facing the piezoelectric actuator 30 is located within the second limiting hole and is limited and engaged. By providing the first limiting hole 411 and the second limiting hole, the self-aligning ball 80 can be limited and fixed through the first limiting hole 411 and the second limiting hole, thereby preventing the position of the self-aligning ball 80 from shifting and ensuring the consistency of the force position of the first elastic member 40.

[0074] like Figure 7 As shown, when the first elastic element 40 applies a preload F to the piezoelectric actuator 30, the piezoelectric actuator 30 abuts against the second elastic element 50. Therefore, the second elastic element 50 applies a reaction force F' to the piezoelectric actuator 30 that is the same magnitude as the preload F but opposite in direction. When the preload F increases, F' also increases accordingly. For example, the range of the preload F is (F... m / V m )×(V x / 2)-A≤F≤(F m / V m )×(V x / 2)+A, where F m V is the maximum output driving force of the piezoelectric actuator 30. m V is the driving voltage required for the piezoelectric actuator 30 to output maximum driving force. x Let V be the peak-to-peak value of the driving voltage ripple, where A is a constant. It should be noted that the peak-to-peak value of the ripple V... x The maximum value of the drive voltage ripple is subtracted from the minimum value; therefore, (F) m / V m )×(V x / 2) represents the force generated by the piezoelectric actuator 30 due to the vibration caused by the driving voltage ripple. Preferably, the preload F = (F m / V m )×(V x / 2), which can counteract the force generated by the shaking.

[0075] However, this is not limiting; the preload F can also be slightly greater than or slightly less than (F... m / V m )×(V x / 2) is also feasible. If the preload F is too small, the effect of suppressing vibration is poor. If the preload F is too large, the piezoelectric actuator 30 will require a larger voltage to drive it, and the voltage boosting process takes a certain amount of time, making it impossible to control the flow rate in time. Therefore, the range of the preload value is (F m / V m )×(V x / 2)-A≤F≤(F m / V m )×(V x / 2)+A, where the range of values ​​for A is F m 1%-10%.

[0076] like Figure 2 As shown, the flow regulating assembly 10 includes: a fixed base 11, a channel component (not shown in the figure), a valve port component 12, a valve core push rod seat 13, a valve core push rod 14, and an elastic diaphragm 15. Please refer to... Figure 8 The channel component has an input channel 91 and an output channel 92. A valve port component 12 is disposed on the channel component, and the valve port component 12 has an inlet hole 121 and an outlet hole 122. The inlet hole 121 communicates with the input channel 91, and the outlet hole 122 communicates with the output channel 92. Fluid flows from the input channel 91 through the inlet hole 121 and the outlet hole 122 to the output channel 92.

[0077] The fixed seat 11 is set on the top of the channel component, and the support block 60 is fixedly connected to the top of the fixed seat 11 by bolts. The fixed seat 11 is provided with a first through hole 211 that runs vertically through it. The first through hole 211 is located above the valve port component 12, and the connecting sleeve 21 is movably set in the first through hole 211.

[0078] The valve core push rod seat 13 is disposed between the fixed seat 11 and the channel component. A third through hole 131 is provided in the valve core push rod seat 13. The third through hole 131 passes through the valve core push rod seat 13 in the vertical direction. The first end of the third through hole 131 is connected to the first through hole 211. The valve port component 12 is located on the second end side of the third through hole 131.

[0079] The valve core push rod 14 is disposed in the third through hole 131. One end of the valve core push rod 14 is opposite to the inlet hole 121, and the other end of the valve core push rod 14 abuts against the bottom surface of the connecting sleeve 21. The elastic diaphragm 15 is annular. The inner ring edge of the elastic diaphragm 15 is connected to the outer peripheral wall of the valve core push rod 14, and the outer ring edge of the elastic diaphragm 15 is connected to the hole wall of the third through hole 131. The elastic diaphragm 15 can undergo elastic deformation when the valve core push rod 14 moves downward, thereby realizing the reset of the valve core push rod 14.

[0080] like Figure 8As shown, the present invention also discloses a mass flow controller, comprising: the aforementioned flow regulating device, an input channel 91, an output channel 92, a flow detection component, and a control module 94. The input channel 91 is connected to the inlet 121 of the flow regulating device, allowing fluid to flow into the mass flow controller from the input channel 91; the output channel 92 is connected to the outlet 122 of the flow regulating device, allowing fluid to flow out of the mass flow controller from the output channel 92; the flow detection component is used to detect the flow rate of the fluid flowing through the input channel 91 and the output channel 92; the control module 94 is used to control the piezoelectric actuator 30 to drive the connector 20 to move based on the detection results of the fluid flow rates flowing through the input channel 91 and the output channel 92, so that the fluid flow rate output from the output channel 92 reaches a preset flow rate value.

[0081] When the piezoelectric actuator 30 of the flow regulating device is de-energized, under the action of the spring 70, the sealing surface at the bottom of the elastic diaphragm 15 blocks the inlet hole 121 and the outlet hole 122, and the input channel 91 and the output channel 92 are no longer connected, blocking the gas passage, and the valve is closed. At this time, the first elastic element 40 has elastically deformed and applies a preload force to the piezoelectric actuator 30.

[0082] When the flow regulating device is used to regulate the flow rate, the control module 94 controls the piezoelectric actuator 30 to extend based on the detection results of the fluid flow rate in the input channel 91 and the output channel 92, so as to move the drive shaft and thereby regulate the fluid flow rate. Specifically, when the piezoelectric actuator 30 is driven by the driving voltage, during the extension process, its two ends compress the first elastic element 40 and the second elastic element 50 respectively. When the piezoelectric actuator 30 compresses the first elastic element 40 and the second elastic element 50 to their limits, the piezoelectric actuator 30 will continue to extend until the second end of the piezoelectric actuator 30 abuts against the support block 60 through the first elastic element 40. At this time, the second end of the piezoelectric actuator 30 has already abutted against the top encapsulation 22 through the second elastic element 50. Therefore, the piezoelectric actuator 30, which continues to extend, will drive the connecting sleeve 21 to move through the top encapsulation 22, so that the second end of the connecting sleeve 21 moves closer to the support block 60 and compresses the spring 70. At the same time, the elastic diaphragm 15 bounces up, so that the inlet hole 121 and the outlet hole 122 are connected and the corresponding opening is opened.

[0083] In other words, the control module 94 adjusts the driving voltage based on the detection results of the fluid flow rate in the input channel 91 and the output channel 92, thereby controlling the extension of the piezoelectric actuator 30 and ensuring that the fluid flow rate output from the output channel 92 reaches the preset flow rate value. Compared with related technologies, the first elastic element 40 applies a preload to the piezoelectric actuator 30 throughout its extension process, ensuring a very tight fit between the piezoelectric ceramic sheets. This effectively reduces the amplitude of vibration caused by piezoelectric ripple, thus improving the stability of flow control. Furthermore, as the driving principle indicates, for the piezoelectric actuator 30 to drive the drive shaft to rotate, the second end of the piezoelectric actuator 30 must first abut against the support block 60. Then, the first end of the piezoelectric actuator 30 abuts against the top encapsulation 22, driving the drive shaft to move and compressing the spring 70. Since the first elastic element 40 of the present invention is connected to the connector 20, the reaction force generated after the first elastic element 40 extends is also applied to the connector 20 and not to the support block 60. Therefore, the reaction force received by the first elastic element 40 will not affect the spring 70, thus ensuring the accuracy of subsequent flow control.

[0084] It is understandable that, such as Figure 8 As shown, the flow detection component includes a first sensor 96, a second sensor 97, and a third sensor 98. The first sensor 96 is used to detect the flow rate in the input channel 91, and a flow limiting element 95 is provided in the output channel 92. The second sensor 97 is used to detect the fluid flow rate between the flow regulating component and the flow limiting element 95 in the output channel 92. The third sensor 98 is used to detect the fluid flow rate downstream of the flow limiting element 95 in the output channel 92.

[0085] like Figure 8 As shown, the control module 94 includes a drive circuit module 941, a voltage acquisition module 942, and a microcontroller unit 943. The first sensor 96 is electrically connected to the microcontroller unit 943 via an A / D conversion circuit, and the second sensor 97 and the third sensor 98 are also electrically connected to the microcontroller unit 943 via A / D conversion circuits. The drive circuit module 941 is electrically connected to both the microcontroller unit 943 and the piezoelectric actuator 30, providing a drive voltage to the piezoelectric actuator 30 to adjust its length; for example... Figure 8 As shown, the voltage acquisition module 942 is electrically connected to the drive circuit module 941 through an A / D conversion circuit and is used to acquire the drive voltage value of the drive circuit module 941. The control module 94 is used to obtain the current drive voltage value when the difference between the actual flow value output by the output channel 92 and the preset flow value is less than a preset range, and to calculate the preset voltage value of the drive circuit at the next moment based on the current preset voltage value of the drive circuit module 941, the current preset flow value, and the actual flow value.

[0086] When in use, after inputting the preset flow rate value, the control module 94 will first obtain the actual flow rate value output by the output channel 92 and compare the actual flow rate value with the preset flow rate value. If the difference between the actual flow rate value output by the output channel 92 and the preset flow rate value is not less than the preset range, it indicates that the difference between the preset flow rate value and the actual flow rate value is large and the fluid flow rate is in an unstable control stage. Therefore, the drive circuit module 941 needs to change the extension and retraction of the piezoelectric actuator 30 controlled by the large voltage to reduce the difference between the preset flow rate value and the actual flow rate value.

[0087] When the difference between the actual flow rate value output by output channel 92 and the preset flow rate value is less than a preset range, control module 94 acquires the current drive voltage value through voltage acquisition module 942, and calculates the preset voltage value of the drive circuit at the next moment based on the current preset voltage value, current preset flow rate value, and actual flow rate value of drive circuit module 941. In other words, by acquiring the current drive voltage value, the drive voltage value at the next moment can be predicted based on the current preset voltage value, current preset flow rate value, and actual flow rate value. This prediction allows for setting the preset voltage value of the drive circuit, thereby correcting the drive voltage value, reducing voltage ripple, lowering the jitter of piezoelectric actuator 30, and improving the stability of flow control.

[0088] For example, the control module 94 calculates the preset voltage value V of the drive circuit module 941 at the next moment according to the following formula. s(i+1) :

[0089] V s(i+1) =K1V mi 2 +K2V mi +K3V xi +K4(F fi -F si )+K5,

[0090] Among them, V xi V represents the current drive voltage value of the drive circuit module 941. mi F is the current preset voltage value of the drive circuit module 941. si F is the preset flow rate value output by output channel 92. fi The output channel 92 represents the actual flow rate value. K1, K2, K3, K4, and K5 are fixed constants.

[0091] It should be noted that K1, K2, K3, K4, and K5 are fixed constants, which can be obtained by obtaining the set valve voltage V multiple times (at least 5 times) using the following method. mi Voltage ripple Vxi Actual traffic F fi Set the flow rate F si The set valve voltage V can be obtained. mi With voltage ripple V xi and actual flow F fi With the set flow rate F si By analyzing the relationship between the valve voltage and voltage ripple and the actual flow rate, we can obtain curves showing the relationship between different valve voltage settings and voltage ripple and the actual flow rate. Based on these curves, we can obtain the values ​​of K1, K2, K3, K4, and K5.

[0092] like Figure 9 As shown, the drive circuit module 941 includes a boost circuit 9412 and a fast start circuit 9411. The boost circuit 9412 is a boost circuit 9412, one of the six basic chopper circuits, and is a switching DC boost circuit 9412 that allows the output voltage to be higher than the input voltage.

[0093] The fast-start circuit 9411 is electrically connected to the piezoelectric actuator 30. When the flow regulating device is turned on, the fast-start circuit 9411 provides a preset starting voltage to the piezoelectric actuator 30 to overcome the preload. Because of the first elastic element 40, the piezoelectric actuator 30 needs to overcome the preload before it can control the fluid flow rate. Therefore, compared to existing technologies, the voltage required to control the fluid flow rate is higher, resulting in a longer boost time and a delay in the mass flow controller. By using the boost circuit 9412 and the fast-start circuit 9411, the boost circuit 9412 can first boost the input power (or a converted power supply) to the maximum voltage of the piezoelectric actuator 30. The fast-start circuit 9411, by receiving the preset voltage signal, can directly provide a starting voltage to the piezoelectric actuator 30, enabling it to overcome the preload and skipping the slow boost stage, thereby improving the response speed of the mass flow controller.

[0094] For example, such as Figure 10As shown, the fast start circuit 9411 includes: a constant current source module 94111, a preset voltage module 94112, a first transistor Q1, a second transistor Q2, a third transistor Q3, and a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a fifth resistor R5. The input terminal of the constant current source module 94111 is electrically connected to the boost circuit 9412 and the collector of the first transistor Q1. The output terminal of the constant current source module 94111 is connected to the base of the first transistor Q1 and then to the input terminal of the preset voltage module 94112. The output terminal of the preset voltage module 94112 is connected to the collector of the third transistor Q3 and the base of the second transistor Q2. The emitter of the first transistor Q1 is connected to one end of the fifth resistor R5. The other end of the fifth resistor R5 is connected to the collector of the second transistor Q2 and one end of the first resistor R1. The other end of the first resistor R1 is connected to one end of the second resistor R2. The other end of the second resistor R2 is connected to the third resistor R3 and the positive terminal of the piezoelectric driver 30. The other end of the third resistor R3 is connected to one end of the fourth resistor R4 and the feedback voltage terminal. The other end of the fourth resistor R4 is grounded, and the negative terminal of the piezoelectric ceramic is grounded.

[0095] When the first transistor Q1 is turned on, the preset voltage module 94112 sets the base voltage of the first transistor Q1 to V1, where V1 > Vnp, and Vnp is the PN junction turn-on voltage of the first transistor Q1. The base voltage of the second transistor Q2 is V2, where V2 > 0Vdc. The start-up voltage value of the piezoelectric driver 30 is V4 = (V1 - Vnp) × (R5 + R1 + R2) / (R5 + R1 + R2 + R3 + R4). By adjusting the valve opening voltage through the preset voltage module 94112, a fast valve start-up is achieved, improving the system response speed.

[0096] The starting voltage V4 provided by the fast start circuit 9411 ranges from V... x -B≤V1≤V x +B, where V x The peak-to-peak value of the voltage ripple is given by B, which is a constant. The value of constant B ranges from 1% to 10% of the highest driving voltage value of the piezoelectric actuator 30.

[0097] It is understandable that the preset voltage module 94112 can be constructed using diodes or transistors. For example, such as... Figure 11 As shown, the first diode D1 and the second diode D2 are connected in series. A high-precision control system is used for control, thereby achieving the function of automatically controlling the preset voltage.

[0098] According to another aspect of the present invention, a flow control method for a mass flow controller is also disclosed. The flow control method is applied to the aforementioned mass flow controller and includes:

[0099] Obtain the actual flow rate F output from output channel 92 fi Obtain the preset flow rate value F si ;

[0100] Compare the actual flow rate with the preset flow rate, and select either the flow rate adjustment mode or the stable control mode based on the comparison result.

[0101] Furthermore, if F fi <F si -σ or F fi >F si When +σ (σ is a constant), that is, the actual flow rate F fi With preset flow rate value F si When the difference is greater than the preset range σ, it indicates that the preset flow rate F is at this time. si Compared with the actual flow value F fi The flow rate difference is significant, and the fluid flow rate is in an unstable control phase. Therefore, selecting the flow regulation mode requires the drive circuit module 941 to change the extension and retraction of the voltage-controlled piezoelectric actuator 30 to reduce the preset flow rate value F. si Compared with the actual flow value F fi gap.

[0102] If F si -σ≤F fi ≤F si When +σ (σ is a constant), that is, the actual flow rate F output by output channel 92. fi With preset flow rate value F si When the difference is less than or equal to the preset range, it indicates that the preset flow rate F is at this time. si Compared with the actual flow value F fi The difference is small, and the fluid flow rate is in a stable control phase. Therefore, the stable control mode is selected.

[0103] In stable control mode, obtain the current drive voltage value V. xi 1. Obtain the current preset voltage value V of the drive circuit module 941 mi The current preset flow rate value F si Actual flow rate F fi ;

[0104] According to the current preset voltage value V of the drive circuit module 941 mi The current preset flow rate value F si Actual flow rate F fi Calculate the preset voltage value V of the drive circuit at the next moment. s(i+1) .

[0105] For example, the preset voltage value V of the drive circuit module 941 at the next moment is obtained according to the following calculation formula. s(i+1) :

[0106] V s(i+1) =K1V mi 2 +K2V mi +K3V xi +K4(F fi -F si )+K5, where K1, K2, K3,

[0107] K4 and K5 are fixed constants.

[0108] The flow control method of the mass flow controller of the present invention, when the actual flow value F fi With preset flow rate value F si When the difference is less than or equal to the preset range, the mass flow controller is in a stable control mode. By detecting the drive voltage value and combining it with the historical and current preset voltage value, preset flow value, and actual flow value, the preset voltage value for the next moment is corrected based on the flow control error caused by the ripple of the current drive voltage value. This reduces the impact of voltage ripple on flow control, improves flow control stability, and thus improves flow control accuracy.

[0109] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A flow regulating device, characterized in that, include: A flow regulating component (10) has an inlet orifice (121) and an outlet orifice (122), the flow regulating component (10) being used to regulate the flow rate of fluid from the inlet orifice (121) to the outlet orifice (122); A connector (20) is movably disposed along its own axis. The connector (20) is driven to cooperate with the flow regulating component (10) so that the flow regulating component (10) regulates the flow rate of the fluid from the inlet hole (121) to the outlet hole (122). A piezoelectric actuator (30) is used to extend under the action of a driving voltage to drive the connector (20) to move along the axial direction; A limiting member is connected between the piezoelectric actuator (30) and the connector (20). The limiting member is used to apply a preload force within a preset range to the piezoelectric actuator (30) along the axial direction of the connector (20) to limit the length change of the piezoelectric actuator (30) caused by voltage fluctuations within a preset range.

2. The flow regulating device according to claim 1, characterized in that, The connector (20) has a first end and a second end along its axial direction, the first end of the connector (20) being away from the flow regulating assembly (10), and the second end of the connector (20) being close to the flow regulating assembly (10); The connector (20) has a mounting cavity (23) inside, and the piezoelectric actuator (30) and the limiting member are both located in the mounting cavity (23). The limiting member is connected to the inner wall of the connector (20) and is located between at least one end of the connector (20) and the piezoelectric actuator (30).

3. The flow regulating device according to claim 2, characterized in that, The limiting component includes: A first elastic element (40) is connected to the inner wall of the connector (20). The first elastic element (40) is located between the second end of the connector (20) and the piezoelectric actuator (30). The piezoelectric actuator abuts against the first elastic element (40). The first elastic element (40) is used to apply the preload force toward the first end of the connector (20).

4. The flow regulating device according to claim 2, characterized in that, The limiting component includes: A second elastic element (50) is located between the first end of the connector (20) and the piezoelectric actuator (30), the piezoelectric actuator abutting against the second elastic element (50), the second elastic element (50) being used to apply the preload towards the second end of the connector (20).

5. The flow regulating device according to claim 3, characterized in that, The flow regulating device further includes: A support block (60) is fixedly connected to the flow regulating component (10). The support block (60) passes through the connector (20). The connector (20) is axially movable relative to the support block (60). The first elastic element (40) is located between the piezoelectric actuator (30) and the support block (60). The piezoelectric actuator (30) contacts the support block (60) through the first elastic element (40).

6. The flow regulating device according to claim 5, characterized in that, The first elastic element (40) includes: The sheet-like portion (41) has a first side facing the piezoelectric actuator (30) and a second side facing the support block (60), and the sheet-like portion (41) is connected to the inner wall of the connector (20); A protrusion (42) is provided on the second side of the sheet-like portion (41) for contacting the support block (60).

7. The flow regulating device according to claim 6, characterized in that, The flow regulating device further includes: A self-aligning ball (80) is disposed between the first elastic member (40) and the piezoelectric actuator (30), and the piezoelectric actuator (30) abuts against the first elastic member (40) through the self-aligning ball (80).

8. The flow regulating device according to claim 7, characterized in that, The first side of the sheet-like portion (41) is provided with a first limiting hole (411), and the side of the self-aligning ball (80) facing the first elastic member (40) is located in the first limiting hole (411) and is limited and fitted. The piezoelectric actuator (30) is provided with a second limiting hole corresponding to the self-aligning ball (80), and the side of the self-aligning ball (80) facing the piezoelectric actuator (30) is located in the second limiting hole and is limited and engaged.

9. The flow regulating device according to claim 3, characterized in that, The range of the preload force F of the first elastic element (40) is (F m / V m )×(V x / 2)-A≤F≤(F m / V m )×(V x / 2)+A, where F m V is the maximum output driving force of the piezoelectric actuator (30). m V is the driving voltage required for the piezoelectric actuator (30) to output maximum driving force. x Let A be the peak-to-peak value of the driving voltage, where A is a constant.

10. The flow regulating device according to claim 9, characterized in that, The range of values ​​for A is F. m 1%-10%.

11. A mass flow controller, characterized in that, include: The flow regulating device according to any one of claims 1 to 10; The fluid flows into the mass flow controller from the input channel (91) and the inlet (121) of the flow regulating device. The output channel (92) is connected to the outlet hole (122) of the flow regulating device, and the fluid flows out of the mass flow controller from the output channel (92); A flow detection component is used to detect the flow rate of fluid flowing through the input channel (91) and the output channel (92); The control module (94) is used to control the piezoelectric actuator (30) to drive the connector (20) to move based on the detection results of the fluid flow rate in the input channel (91) and the output channel (92), so that the fluid flow rate output by the output channel (92) reaches a preset flow rate value.

12. The mass flow controller according to claim 11, characterized in that, The control module (94) includes: The drive circuit module (941) is electrically connected to the piezoelectric actuator (30) and is used to provide a drive voltage to the piezoelectric actuator (30) to adjust the length of the piezoelectric actuator (30); The voltage acquisition module (942) is electrically connected to the drive circuit module (941) and is used to acquire the drive voltage value of the drive circuit module (941); The control module (94) is used to obtain the current driving voltage value when the difference between the actual flow value output by the output channel (92) and the preset flow value is less than or equal to a preset range, and to calculate the preset voltage value of the driving circuit at the next moment based on the current preset voltage value of the driving circuit module (941), the current preset flow value, and the actual flow value.

13. The mass flow controller according to claim 12, characterized in that, The control module (94) calculates the preset voltage value V of the drive circuit module (941) at the next moment according to the following formula. s(i+1) : V s(i+1) =K1V mi 2 +K2V mi +K3V xi +K4(F fi -F si )+K5, Among them, V xi V represents the current driving voltage value of the driving circuit module (941). mi F is the current preset voltage value of the drive circuit module (941). si F is the preset flow rate value output by the output channel (92). fi The output channel (92) outputs the actual flow rate value, where K1, K2, K3, K4, and K5 are fixed constants.

14. The mass flow controller according to claim 12, characterized in that, The drive circuit module (941) includes: A quick-start circuit (9411) is electrically connected to the piezoelectric actuator (30). The quick-start circuit (9411) is used to provide a starting voltage to the piezoelectric actuator (30) when the flow regulating device is turned on, so that the piezoelectric actuator (30) can overcome the preload.

15. The mass flow controller according to claim 14, characterized in that, The starting voltage V1 provided by the fast start circuit (9411) ranges from V... x -B≤V1≤V x +B, where V x Let be the peak-to-peak value of the voltage ripple, and B be a constant.

16. The mass flow controller according to claim 15, characterized in that, The value of B is 1%-10% of the highest driving voltage of the piezoelectric actuator (30).

17. A flow control method for a mass flow controller, characterized in that, The flow control method is applied to the mass flow controller according to any one of claims 12-16, and the flow control method includes: When the difference between the actual flow rate value output by the output channel (92) and the preset flow rate value is less than a preset range, the current driving voltage value is obtained; Obtain the current preset voltage value, the current preset flow rate value, and the actual flow rate value of the drive circuit module (941); The preset voltage value of the drive circuit at the next moment is calculated based on the current preset voltage value of the drive circuit module (941), the current preset flow rate value, and the actual flow rate value.

18. The flow control method according to claim 17, characterized in that, The step of calculating the preset voltage value of the drive circuit at the next moment based on the current preset voltage value of the drive circuit module (941), the current preset flow rate value, and the actual flow rate value specifically includes: The preset voltage value V of the drive circuit module (941) at the next moment is obtained according to the following calculation formula. s(i+1) : V s(i+1) =K1V mi 2 +K2V mi +K3V xi +K4(F fi -F si )+K5, Among them, V xi V represents the current driving voltage value of the driving circuit module (941). mi F is the current preset voltage value of the drive circuit module (941). si F is the preset flow rate value output by the output channel (92). fi The output channel (92) outputs the actual flow rate value, where K1, K2, K3, K4, and K5 are fixed constants.

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