A piezoelectric pump control method

Abstract

The application provides a piezoelectric pump control method, which comprises the following steps: step one, acquiring the pressure P of the liquid outlet end of the piezoelectric pump and the driving voltage V of the piezoelectric pump; step two, obtaining the formula V = φ (P) according to the data in step one; step three, detecting the pressure P of the liquid outlet end of the piezoelectric pump in advance through a pressure sensor, and calculating the driving voltage required by the piezoelectric pump according to the formula V = φ (P) and the data of the pressure P; and step four, applying the required driving voltage to the piezoelectric pump to control the piezoelectric pump. The piezoelectric pump control method detects the pressure value of the outlet end of the piezoelectric pump, adjusts the driving voltage of the piezoelectric ceramic adaptively, and effectively reduces the power consumption of the piezoelectric pump under the premise of ensuring the single pumping precision.

Description

Technical Field

[0001] This invention relates to the field of fluid machinery, and more specifically to a piezoelectric pump control method. Background Technology

[0002] Currently, pump-assisted infusion solutions typically include hydraulic bags, volumetric pumps, and drug reservoirs. Under electrical signal control, the volumetric micro-pump draws a fixed volume of hydraulic fluid from the liquid bag and then pumps it into the liquid chamber of the hydraulic drug reservoir, thereby pushing the piston of the hydraulic drug reservoir forward. The piston then pushes the drug fluid in the drug reservoir's chamber out of the hydraulic drug reservoir.

[0003] High-precision infusion is required for pumped fluid delivery. Current technology uses a fixed voltage waveform to drive a piezoelectric ceramic, which in turn moves a volumetric pump to achieve this precision. This approach simplifies control by using a fixed voltage amplitude to drive the piezoelectric ceramic. However, higher outlet pressures require higher voltages to ensure consistent output. Using a fixed amplitude to drive the piezoelectric ceramic necessitates using the voltage at maximum back pressure, leading to power waste at lower pressures.

[0004] Therefore, the technical problem that this application needs to solve is: how to reduce the power consumption of the piezoelectric pump. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a piezoelectric pump control method. By detecting the pressure value at the outlet of the piezoelectric pump and adaptively adjusting the driving voltage of the piezoelectric ceramic, the power consumption of the piezoelectric pump is effectively reduced while ensuring the pumping accuracy per cycle.

[0006] Specifically, this invention proposes a piezoelectric pump control method, comprising the following steps:

[0007] Step 1: Obtain the data of the pressure P at the outlet of the piezoelectric pump and the data of the driving voltage V when the piezoelectric pump is working;

[0008] Step 2: Based on the data from Step 1, derive the formula V = φ(P);

[0009] Step 3: The pressure P at the outlet of the piezoelectric pump is detected in advance by the pressure sensor. The control system receives the pressure P data and calculates the driving voltage required for the piezoelectric pump to work according to the formula V=φ(P).

[0010] Step 4: The control system applies the required drive voltage to the piezoelectric pump to control its operation.

[0011] Preferably, the piezoelectric pump is a positive displacement micropump.

[0012] Furthermore, the piezoelectric pump control system used in this method includes a piezoelectric pump, a pressure sensor, and a control system. The piezoelectric pump changes the volume of the pump chamber through piezoelectric ceramics. The pressure sensor is used to detect the pressure at the outlet of the piezoelectric pump and feed the pressure data back to the control system. The control system calculates the required driving voltage value for the piezoelectric pump and applies the corresponding voltage to the piezoelectric pump.

[0013] Furthermore, the relationship between the pressure P at the outlet of the piezoelectric pump and the driving voltage V during operation is as follows:

[0014] V=0.001302083×P^3+0.015625×P^2+0.666666667×P+70

[0015] The unit of pressure P is psi, and the unit of voltage V is V.

[0016] Preferably, the driving voltage required to achieve the pressure at the outlet of the piezoelectric pump is as follows:

[0017] When the pressure at the outlet of the piezoelectric pump is 0 psi, the required drive voltage is 70V.

[0018] Alternatively, when the pressure at the outlet of the piezoelectric pump is 4 psi, the required drive voltage is 73 V;

[0019] Alternatively, when the pressure at the outlet of the piezoelectric pump is 8 psi, the required drive voltage is 77 V;

[0020] Alternatively, when the pressure at the outlet of the piezoelectric pump is 12 psi, the required drive voltage is 82.5 V;

[0021] Alternatively, when the pressure at the outlet of the piezoelectric pump is 16 psi, the required drive voltage is 90 V.

[0022] Preferably, the driving voltage required to achieve the pressure at the outlet of the piezoelectric pump is as follows:

[0023] When the pressure at the outlet of the piezoelectric pump is less than or equal to 4 psi, the required drive voltage is 73V.

[0024] Alternatively, when the pressure at the outlet of the piezoelectric pump is greater than 4 psi and less than or equal to 8 psi, the required drive voltage is 77V.

[0025] Alternatively, when the pressure at the outlet of the piezoelectric pump is greater than 8 psi and less than or equal to 12 psi, the required drive voltage is 82.5V;

[0026] Alternatively, when the pressure at the outlet of the piezoelectric pump is greater than 12 psi and less than or equal to 16 psi, the required drive voltage is 90V.

[0027] Preferably, the piezoelectric pump is provided with an inlet and an outlet, the piezoelectric pump is provided with an inlet channel for connecting the inlet and the pump chamber, and the piezoelectric pump is provided with an outlet channel for connecting the outlet and the pump chamber;

[0028] The piezoelectric pump also includes a pump diaphragm and a piezoelectric ceramic. The pump diaphragm is used to change the volume of the pump chamber, and the pump diaphragm is connected to the piezoelectric ceramic via a connector. The piezoelectric ceramic is electrically connected to the circuit board of the piezoelectric pump.

[0029] The liquid inlet channel is equipped with an inlet check valve;

[0030] The liquid outlet channel is equipped with an outlet check valve.

[0031] Furthermore, the piezoelectric pump includes a support structure for mounting the piezoelectric ceramic.

[0032] Furthermore, the piezoelectric pump is also equipped with a storage device.

[0033] Furthermore, the piezoelectric pump control method described above is applied to drug delivery methods.

[0034] Beneficial effects:

[0035] 1. In the piezoelectric pump control method of this scheme, the power consumption can be significantly reduced by adaptively adjusting the driving voltage of the volumetric micropump.

[0036] 2. In the piezoelectric pump control method of this scheme, the problem of excessive output force of piezoelectric ceramic 14 when the pressure at the liquid outlet is low is improved, thereby improving the safety and service life of the volumetric micropump. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0038] Figure 1 This is a schematic diagram illustrating the principle of the piezoelectric pump control method proposed in this embodiment;

[0039] Figure 2 This is a schematic diagram of the internal structure of the piezoelectric pump in the initial state of the piezoelectric pump control method proposed in this embodiment;

[0040] Figure 3 This is a schematic diagram of the internal structure of the piezoelectric pump under positive voltage in the piezoelectric pump control method proposed in this embodiment;

[0041] Figure 4 This is a schematic diagram of the internal structure of the piezoelectric pump under reverse voltage in the piezoelectric pump control method proposed in this embodiment.

[0042] The reference numerals used in the attached figures are as follows:

[0043] 11-Piezoelectric pump; 12-Pressure sensor; 13-Control system; 14-Piezoelectric ceramic; 15-Pump chamber; 16-Inlet; 17-Outlet; 18-Inlet channel; 19-Outlet channel; 20-Pump diaphragm; 21-Connector; 22-Circuit board; 23-Inlet check valve; 24-Outlet check valve; 25-Support structure; 26-Storage unit; 27-Electrode; 28-End cap. Detailed Implementation

[0044] The technical solutions of this application will be further described below with reference to specific embodiments, but this application is not limited to these embodiments.

[0045] This embodiment proposes a piezoelectric pump control method, including the following steps:

[0046] Step 1: Obtain the data of the pressure P at the outlet of the piezoelectric pump 11 and the data of the driving voltage V when the piezoelectric pump 11 is working;

[0047] Step 2: Based on the data from Step 1, derive the formula V = φ(P);

[0048] Step 3: The pressure P at the outlet of the piezoelectric pump 11 is detected in advance by the pressure sensor 12. The control system 13 receives the pressure P data and calculates the driving voltage required for the piezoelectric pump 11 to work according to the formula V=φ(P).

[0049] Step 4: The control system 13 applies the required drive voltage to the piezoelectric pump 11 to control the operation of the piezoelectric pump 11.

[0050] The technical advantage of this solution is that by detecting the pressure value at the outlet of the piezoelectric pump 11 and adaptively adjusting the driving voltage of the piezoelectric ceramic 14, the power consumption of the piezoelectric pump 11 is effectively reduced while ensuring the pumping accuracy of a single pumping operation.

[0051] Furthermore, the piezoelectric pump control method described above is applied to drug delivery methods.

[0052] Furthermore, the piezoelectric pump 11 is a positive displacement micro pump.

[0053] like Figure 1 and Figure 2 As shown, the piezoelectric pump control system used in this method includes a piezoelectric pump 11, a pressure sensor 12, and a control system 13. The piezoelectric pump 11 changes the volume of the pump chamber 15 through the piezoelectric ceramic 14. The pressure sensor 12 is used to detect the pressure at the outlet of the piezoelectric pump 11 and feed the pressure data back to the control system 13. The control system 13 calculates the required driving voltage value of the piezoelectric pump 11 and applies the corresponding voltage to the piezoelectric pump 11.

[0054] In this scheme, pressure sensor 12 is used to collect the pressure value P at the outlet of piezoelectric pump 11; control system 13 is used to output drive voltage waveform to control piezoelectric ceramic 14, and its output voltage V can be automatically adjusted according to the collected pressure value P; piezoelectric ceramic 14 generates different displacement changes according to the drive waveform, which is used to press or pull the volumetric micropump to complete the fluid delivery.

[0055] In this scheme, when the pressure at the outlet of the volumetric pump is 0, the driving voltage required by the piezoelectric ceramic 14 is Vmin; when the pressure at the outlet of the volumetric pump is the maximum value Pmax, the maximum driving voltage required by the piezoelectric ceramic 14 is Vmax.

[0056] Furthermore, the relationship between the pressure P at the outlet of the piezoelectric pump 11 and the driving voltage V when the piezoelectric pump 11 is working is as follows:

[0057] V=0.001302083×P^3+0.015625×P^2+0.666666667×P+70

[0058] The unit of pressure P is psi, and the unit of voltage V is V.

[0059] In practical applications, the outlet pressure range of the positive displacement micropump is 0–16 psi. The driving voltage required to achieve the outlet pressure of the piezoelectric pump 11 is as follows:

[0060] When the pressure at the outlet of the piezoelectric pump 11 is 0 psi, the required drive voltage is 70 V.

[0061] Alternatively, when the pressure at the outlet of the piezoelectric pump 11 is 4 psi, the required drive voltage is 73 V;

[0062] Alternatively, when the pressure at the outlet of the piezoelectric pump 11 is 8 psi, the required drive voltage is 77 V;

[0063] Alternatively, when the pressure at the outlet of the piezoelectric pump 11 is 12 psi, the required drive voltage is 82.5 V;

[0064] Alternatively, when the pressure at the outlet of the piezoelectric pump 11 is 16 psi, the required drive voltage is 90 V.

[0065] This scheme measures the pressure P at the outlet of the piezoelectric pump 11 through multi-point calibration, and calculates and outputs the minimum driving voltage using the formula V = φ(P). Since the displacement S of the piezoelectric ceramic 14 is proportional to the driving voltage V, it ensures the pumping volume of the volumetric pump per cycle while avoiding excessively high driving voltage. According to the formula for storing electrical energy in the piezoelectric ceramic 14, P1 = 1 / 2 × C × V^2, where C is the capacitance of the piezoelectric ceramic 14 (800 nF in this scheme), the power consumption per pump cycle can be reduced by a maximum of 0.00128 joules using the control method of automatically adjusting the output voltage based on the outlet pressure.

[0066] As one embodiment of this invention, the driving voltage required to achieve the pressure at the outlet of the piezoelectric pump 11 is as follows:

[0067] When the pressure at the outlet of the piezoelectric pump 11 is less than or equal to 4 psi, the required drive voltage is 73 V.

[0068] Alternatively, when the pressure at the outlet of the piezoelectric pump 11 is greater than 4 psi and less than or equal to 8 psi, the required drive voltage is 77 V.

[0069] Alternatively, when the pressure at the outlet of the piezoelectric pump 11 is greater than 8 psi and less than or equal to 12 psi, the required drive voltage is 82.5V;

[0070] Alternatively, when the pressure at the outlet of the piezoelectric pump 11 is greater than 12 psi and less than or equal to 16 psi, the required drive voltage is 90 V.

[0071] This scheme adopts a segmented calibration method to detect the pressure at the outlet of the piezoelectric pump 11 and feed it back to the control system 13. The control system 13 applies a corresponding driving voltage to the piezoelectric ceramic 14 according to the pressure range.

[0072] As one implementation method of this embodiment, such as Figure 2 As shown, the piezoelectric pump 11 is provided with an inlet 16 and an outlet 17. The piezoelectric pump 11 is provided with an inlet channel 18 for connecting the inlet 16 and the pump chamber 15, and an outlet channel 19 for connecting the outlet 17 and the pump chamber 15.

[0073] The piezoelectric pump 11 also includes a pump diaphragm 20 and a piezoelectric ceramic 14. The pump diaphragm 20 is used to change the volume of the pump chamber 15, and the pump diaphragm 20 is connected to the piezoelectric ceramic 14 through a connector 21. The piezoelectric ceramic 14 is electrically connected to the circuit board 22 of the piezoelectric pump 11.

[0074] An inlet check valve 23 is provided in the liquid inlet channel 18;

[0075] An outlet check valve 24 is provided in the liquid outlet channel 19.

[0076] Furthermore, the piezoelectric pump 11 is provided with an end cap 28, and the end cap 28 is provided with a liquid inlet 16.

[0077] Furthermore, the piezoelectric pump 11 includes a support structure 25 for mounting the piezoelectric ceramic 14.

[0078] Furthermore, the piezoelectric pump 11 is also equipped with a storage device 26.

[0079] Furthermore, the circuit board 22 is provided with electrodes 27.

[0080] The piezoelectric pump 11 operates as follows:

[0081] like Figure 3 As shown, when a positive voltage is applied to both ends of the piezoelectric ceramic 14, the piezoelectric ceramic 14 generates an upward deformation displacement, the pump diaphragm 20 of the volumetric micropump is pulled upward, the volume of the pump chamber 15 increases, the outlet check valve 24 closes, the inlet check valve 23 opens, and half the dose of fluid enters the pump chamber 15 from the inlet 16.

[0082] like Figure 4 As shown, when a reverse voltage is applied across the piezoelectric ceramic 14, the piezoelectric ceramic 14 undergoes a downward deformation displacement, pressing the pump diaphragm 20 of the positive displacement micropump downwards. The volume of the pump chamber 15 decreases, the outlet check valve 24 opens, and the inlet check valve 23 closes, allowing one dose of fluid from the pump chamber 15 to be discharged from the outlet 17. When the pressure at the outlet 17 increases, the piezoelectric ceramic 14 needs to generate greater pressure to press the pump diaphragm 20 to the bottom. The control system 13 provides a greater voltage to the piezoelectric ceramic 14 of the positive displacement micropump.

[0083] When the voltage across the piezoelectric ceramic 14 is 0 psi, half the dose of fluid for the pellet enters the pump chamber 15 through the inlet 16. The piezoelectric ceramic 14 and the pump diaphragm 20 return to their horizontal positions, and the volume of the pump chamber 15 returns to its initial state. Figure 2 As shown, at this time, the outlet check valve 24 is closed, the inlet check valve 23 is closed, the volume of the pump chamber 15 returns to its initial size, and the inside is filled with liquid.

[0084] For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of this invention, and these all fall within the protection scope of this invention.

Claims

1. A piezoelectric pump control method, characterized in that, Includes the following steps: Step 1: Obtain the data of the pressure P at the outlet of the piezoelectric pump (11) and the data of the driving voltage V when the piezoelectric pump (11) is working; Step 2: Based on the data from Step 1, derive the formula V = φ(P); Step 3: The pressure P at the outlet of the piezoelectric pump (11) is detected in advance by the pressure sensor (12). The control system (13) receives the pressure P data and calculates the driving voltage required for the piezoelectric pump (11) to work according to the formula V=φ(P). Step 4: The control system (13) applies the required drive voltage to the piezoelectric pump (11) to control the operation of the piezoelectric pump (11).

2. The piezoelectric pump control method according to claim 1, characterized in that, The piezoelectric pump (11) is a positive displacement micro pump.

3. The piezoelectric pump control method according to claim 1, characterized in that, The piezoelectric pump control system used in this method includes a piezoelectric pump (11), a pressure sensor (12), and a control system (13). The piezoelectric pump (11) changes the volume of the pump chamber (15) through a piezoelectric ceramic (14). The pressure sensor (12) is used to detect the pressure at the outlet of the piezoelectric pump (11) and feed the pressure data back to the control system (13). The control system (13) calculates the required driving voltage value of the piezoelectric pump (11) and applies the corresponding voltage to the piezoelectric pump (11).

4. The piezoelectric pump control method according to claim 1, characterized in that, The relationship between the pressure P at the outlet of the piezoelectric pump (11) and the driving voltage V when the piezoelectric pump (11) is working is as follows: V=0.001302083×P^3+0.015625×P^2+0.666666667×P+70 The unit of pressure P is psi, and the unit of voltage V is V.

5. The piezoelectric pump control method according to claim 1, characterized in that, The driving voltage required to achieve the pressure at the outlet of the piezoelectric pump (11) is as follows: When the pressure at the outlet of the piezoelectric pump (11) is 0 psi, the required drive voltage is 70 V; Alternatively, when the pressure at the outlet of the piezoelectric pump (11) is 4 psi, the required drive voltage is 73 V; Alternatively, when the pressure at the outlet of the piezoelectric pump (11) is 8 psi, the required drive voltage is 77 V; Alternatively, when the pressure at the outlet of the piezoelectric pump (11) is 12 psi, the required drive voltage is 82.5 V; Alternatively, when the pressure at the outlet of the piezoelectric pump (11) is 16 psi, the required drive voltage is 90 V.

6. The piezoelectric pump control method according to claim 1, characterized in that, The driving voltage required to achieve the pressure at the outlet of the piezoelectric pump (11) is as follows: When the pressure at the outlet of the piezoelectric pump (11) is less than or equal to 4 psi, the required drive voltage is 73 V; Alternatively, when the pressure at the outlet of the piezoelectric pump (11) is greater than 4 psi and less than or equal to 8 psi, the required drive voltage is 77 V; Alternatively, when the pressure at the outlet of the piezoelectric pump (11) is greater than 8 psi and less than or equal to 12 psi, the required drive voltage is 82.5 V; Alternatively, when the pressure at the outlet of the piezoelectric pump (11) is greater than 12 psi and less than or equal to 16 psi, the required drive voltage is 90 V.

7. The piezoelectric pump control method according to claim 3, characterized in that, The piezoelectric pump (11) is provided with an inlet (16) and an outlet (17), and the piezoelectric pump (11) is provided with an inlet channel (18) for connecting the inlet (16) and the pump chamber (15), and the piezoelectric pump (11) is provided with an outlet channel (19) for connecting the outlet (17) and the pump chamber (15); The piezoelectric pump (11) also includes a pump diaphragm (20) and a piezoelectric ceramic (14). The pump diaphragm (20) is used to change the volume of the pump chamber (15), and the pump diaphragm (20) is connected to the piezoelectric ceramic (14) through a connector (21). The piezoelectric ceramic (14) is electrically connected to the circuit board (22) of the piezoelectric pump (11). The liquid inlet channel (18) is equipped with an inlet check valve (23); The liquid outlet channel (19) is equipped with an outlet check valve (24).

8. The piezoelectric pump control method according to claim 7, characterized in that, The piezoelectric pump (11) includes a support structure (25) for mounting the piezoelectric ceramic (14).

9. The piezoelectric pump control method according to claim 1, characterized in that, The piezoelectric pump (11) is also equipped with a storage device (26).

10. The piezoelectric pump control method according to claim 1, characterized in that, This method is applied to drug infusion methods.

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