Self-adaptive pressure control fluid supercharging device

Abstract

The invention relates to the technical field of hydraulic variable-capacity machinery, and provides a self-adaptive pressure control fluid supercharging device which comprises the following steps: acquiring the fluid inlet pressure and the fluid outlet pressure of the fluid supercharging device and the rotating speed of an eccentric shaft, and acquiring the time duration of a supercharging process in an acquisition period; the cavitation phenomenon possibility in the pressurization process and the pressurization cavitation possibility in the collection period are obtained, and whether the rotating speed and the pump of the fluid pressurization device are adjusted or not is judged; for the fluid supercharging device with the rotating speed needing to be adjusted, the eccentric shaft adjusting rotating speed of the collection period is determined, the rotating speed of the eccentric shaft is adjusted and controlled, and a secondary judgment result for adjusting the rotating speed of the eccentric shaft and a pump is determined; and when the rotating speed of the eccentric shaft is adjusted for a long time, the rotating speed of the eccentric shaft is further adjusted and controlled until a judgment result of normal operation of the fluid supercharging device is obtained. The problem that the pressure control effect is affected by the cavitation phenomenon is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of liquid variable volume mechanical technology, and particularly relates to a fluid pressurizing device with self-adaptive pressure control. BACKGROUND

[0002] The fluid pressurizing device can increase fluid pressure, provide required high-pressure fluid for various industrial processes, and pump fluid from a low-pressure area to a high-pressure area to realize fluid delivery. The pressure control of the fluid pressurizing device can adjust the rotational speed of the pressurizing pump or the fluid pressurizing device and the control parameters of the valve according to system dynamics to maintain the target pressure.

[0003] However, the pressure control of the fluid pressurizing device is limited in scope. When cavitation occurs, the parameters such as pressure and flow of the system will exceed the applicable scope of regulation, resulting in poor pressure control effect of the fluid pressurizing device and abnormal fluid pressurization. SUMMARY

[0004] The present application provides a fluid pressurizing device with self-adaptive pressure control to solve the problem of poor pressure control effect and abnormal fluid pressurization caused by cavitation when the fluid pressurizing device performs pressure control. The technical solution adopted is as follows:

[0005] One embodiment of the present application provides a fluid pressurizing device with self-adaptive pressure control, which comprises the following steps:

[0006] Collecting the fluid inlet pressure, fluid outlet pressure and rotational speed of the eccentric shaft of the fluid pressurizing device within a preset collection period to obtain the time length of the pressurization process within the collection period;

[0007] Determining the cavitation possibility of the same pressurization process according to the difference between the ideal pressurization process and the change trend of all fluid inlet pressures collected in the same pressurization process, determining the pressurization cavitation possibility of the collection period according to the change trend of the cavitation possibilities of all pressurization processes in the collection period and the difference between the fitting curves of all pressurization processes, and determining whether to adjust the rotational speed and the pump of the fluid pressurizing device according to the pressurization cavitation possibility of the collection period;

[0008] For the fluid pressurizing device that needs to adjust the rotational speed, determining the eccentric shaft adjustment rotational speed of the collection period according to the pressurization cavitation possibility of the collection period, the fluid outlet pressure and the rotational speed of the eccentric shaft collected in the collection period, realizing the regulation and control of the rotational speed of the eccentric shaft according to the eccentric shaft adjustment rotational speed of the collection period, and determining the second judgment result of whether to adjust the rotational speed and the pump of the fluid pressurizing device according to the difference between the eccentric shaft adjustment rotational speed of the collection period and the rotational speed of the eccentric shaft at the last collection time in the collection period;

[0009] When the eccentric shaft rotating speed is adjusted for a long time, the supercharging cavitation possibility and the rotating speed change rate of all adjustment periods are obtained, the rotating speed of the eccentric shaft is regulated in combination with the rotating speed of the eccentric shaft of all adjustment periods, and the rotating speed of the eccentric shaft is regulated until a determination result of normal operation of the fluid supercharging device is obtained.

[0010] Further, the determination method of the cavitation possibility of the supercharging process is:

[0011] The fluid inlet pressures collected in the same supercharging process in the collection period are curve-fitted to obtain a fitting curve of the fluid inlet pressures in the same supercharging process, the fitting values of the collection time corresponding to all the fluid inlet pressures in the same supercharging process are obtained according to the fitting curve, and the difference between the fluid inlet pressure and the fitting value at the same collection time is recorded as the fitting error at the same collection time.

[0012] The collection time corresponding to the maximum value of all the fluid inlet pressures collected in the same supercharging process is recorded as the peak time of the same supercharging process.

[0013] The product of the absolute value of the fitting error at the peak time of the supercharging process and the standard deviation of the fitting values at all the collection times in the supercharging process is recorded as the cavitation possibility of the supercharging process.

[0014] Further, the acquisition method of the supercharging cavitation possibility of the collection period is:

[0015] The cavitation possibilities of all the supercharging processes in the collection period are arranged in the order of the supercharging processes, and the cavitation possibilities are linearly fitted to obtain the slope of the fitting straight line of the collection period.

[0016] The sum of the Fréchet distances between the fitting curves of all the supercharging processes in the collection period is recorded as the supercharging process difference of the collection period.

[0017] The normalized value of the product of the average of the cavitation possibilities of all the supercharging processes in the collection period, the slope of the fitting straight line of the collection period, and the supercharging process difference of the collection period is recorded as the supercharging cavitation possibility of the collection period.

[0018] Further, the specific method of determining whether to adjust the rotating speed and the pump of the fluid supercharging device according to the supercharging cavitation possibility of the collection period includes:

[0019] When the supercharging cavitation possibility of the collection period is less than a first cavitation threshold, the fluid supercharging device is not adjusted.

[0020] When the supercharging cavitation possibility of the collection period is greater than a second cavitation threshold, an adjustment instruction is sent to the pump of the fluid supercharging device to adjust the pump to realize pressure control.

[0021] adjusting the rotating speed of the fluid pressurizing device when the pressurizing cavitation possibility of the collection period is greater than or equal to the first cavitation threshold value and less than or equal to the second cavitation threshold value;

[0022] wherein the first cavitation threshold value and the second cavitation threshold value are both preset threshold values, and the first cavitation threshold value is less than the second cavitation threshold value.

[0023] Further, the determination method of the eccentric shaft adjustment rotating speed of the collection period is:

[0024] the reciprocal of the difference between the pressurizing cavitation possibility of the collection period and the first cavitation threshold value is denoted as the first normalized value of the collection period;

[0025] the average value of the fluid outlet pressure at the last collection time of all pressurizing processes collected in the collection period is denoted as the actual pressurization of the collection period, and the ratio of the actual pressurization of the collection period to the target fluid pressure after the liquid pressurization is denoted as the first ratio of the collection period;

[0026] the product of the first normalized value, the first ratio of the collection period, and the rotating speed of the eccentric shaft at the last collection time in the collection period is denoted as the eccentric shaft adjustment rotating speed of the collection period.

[0027] Further, the method of adjusting the rotating speed of the eccentric shaft according to the eccentric shaft adjustment rotating speed of the collection period comprises:

[0028] the rounding value of the eccentric shaft adjustment rotating speed of the collection period is taken as the value of the rotating speed of the eccentric shaft after the collection period.

[0029] Further, the second determination result of whether to adjust the eccentric shaft rotating speed and the pump of the fluid pressurizing device according to the difference between the eccentric shaft adjustment rotating speed of the collection period and the rotating speed of the eccentric shaft at the last collection time in the collection period comprises:

[0030] the absolute value of the difference between the rotating speed of the eccentric shaft at the last collection time in the collection period and the eccentric shaft adjustment rotating speed of the collection period is denoted as the first difference of the collection period, and the ratio of the first difference of the collection period to the rotating speed of the eccentric shaft at the last collection time in the collection period is denoted as the rotating speed change rate of the collection period;

[0031] the second determination result of whether to adjust the eccentric shaft rotating speed and the pump of the fluid pressurizing device is determined according to the value of the rotating speed change rate of the collection period.

[0032] Further, the method of determining the second determination result of whether to adjust the eccentric shaft rotating speed and the pump of the fluid pressurizing device according to the value of the rotating speed change rate of the collection period comprises:

[0033] When the rotational speed change rate of the acquisition period is less than the third cavitation threshold, a pump of the fluid pressurizing device is sent an adjustment instruction, and the pump is adjusted to achieve pressure control;

[0034] When the rotational speed change rate of the acquisition period is greater than or equal to the third cavitation threshold, T seconds are taken as an adjustment period, the pressurization cavitation possibility of the adjustment period is obtained in the same way as the pressurization cavitation possibility of the acquisition period, and a judgment result of whether to adjust the eccentric shaft rotational speed and the pump of the fluid pressurizing device is obtained according to the pressurization cavitation possibility of the adjustment period, where T is a preset time threshold.

[0035] Further, the case of adjusting the eccentric shaft rotational speed for a long time specifically includes:

[0036] Four adjustment periods are continuously selected, and the judgment result corresponding to each adjustment period is to adjust the eccentric shaft rotational speed of the fluid pressurizing device.

[0037] Further, the adjustment of the eccentric shaft rotational speed combining the eccentric shaft rotational speeds of all adjustment periods includes the following specific method:

[0038] The difference between the pressurization cavitation possibility of the adjustment period and the pressurization cavitation possibility of the previous adjacent adjustment period is recorded as the pressurization cavitation possibility change rate of the adjustment period; the pressurization cavitation possibility change rates and the rotational speed change rates of all adjustment periods are linearly fitted to obtain a first fitting straight line, and a fitting value of the pressurization cavitation possibility change rate corresponding to the rotational speed change rate of the last adjustment period is calculated according to the first fitting straight line of the adjustment period, and is recorded as a first fitting value;

[0039] A sequence formed by arranging the pressurization cavitation possibility change rates of all adjustment periods in the order of the adjustment periods is recorded as a first sequence, a sequence formed by adding the first fitting value after the first sequence is recorded as a second sequence, a sequence formed by arranging the rotational speed change rates of all adjustment periods in the order of the adjustment periods is recorded as a third sequence, a sequence formed by adding the rotational speed change rate of the last adjustment period after the third sequence is recorded as a fourth sequence, a correlation coefficient of the first sequence and the third sequence is recorded as a first correlation coefficient, a correlation coefficient of the second sequence and the fourth sequence is recorded as a second correlation coefficient, a difference between the first correlation coefficient and the second correlation coefficient is recorded as a correlation coefficient difference, and a power with the natural constant as the base number and the correlation coefficient difference as the exponent is recorded as a first exponential power.

[0040] The average of the rotational speeds of all eccentric shafts collected in the adjustment period is recorded as the eccentric shaft rotational speed average of the adjustment period, the pressurization cavitation possibility of all adjustment periods and the eccentric shaft rotational speed average of the adjustment period are fitted to obtain a second fitting straight line, and a fitting value of the eccentric shaft rotational speed average when the pressurization cavitation possibility takes the first cavitation threshold is obtained according to the second fitting straight line, and is recorded as a second fitting value.

[0041] The product of the first fitting value and the first exponential power is denoted as a first numerator, the sum of the first exponential power and the number 1 is denoted as a first denominator, and the ratio of the first numerator to the first denominator is denoted as a secondary eccentric shaft adjustment speed of the last adjustment period. The secondary eccentric shaft adjustment speed of the last adjustment period is taken as the rotation speed of the eccentric shaft at each collection time after the last adjustment period.

[0042] The present application has the following beneficial effects:

[0043] The present application has the following beneficial effects: BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0045] Figure 1 A schematic diagram of a fluid pressurization device with adaptive pressure control according to an embodiment of the present application;

[0046] Figure 2 A schematic diagram of a flow regulation control device according to an embodiment of the present application;

[0047] Figure 3 A schematic diagram of a fluid pressurization device according to an embodiment of the present application;

[0048] Figure 4 A schematic diagram of a portion of a motor rotor driven pressurization chamber for fluid compression according to an embodiment of the present application;

[0049] Figure 5 A flowchart of a process for obtaining a likelihood of cavitation according to an embodiment of the present application. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0051] Referring to Figure 1 , a flowchart of a fluid pressurization device with adaptive pressure control according to an embodiment of the present application is shown. The method comprises the following steps:

[0052] In step S001, the fluid inlet pressure, the fluid outlet pressure and the rotational speed of the eccentric shaft of the fluid pressurization device in a preset collection period are collected, and the time length of the pressurization process in the collection period is obtained.

[0053] The fluid pressurization device is a reciprocating plunger type fluid pressurization device, which realizes pressurization by periodic compression of the cavity by the plunger. The pressurization process of the fluid pressurization device is that the eccentric shaft rotates to drive the slider to move backward, the plunger moves to expand the cavity volume, the inlet cock is opened, and the fluid fills the cavity under the action of atmospheric pressure. The compression stroke of the fluid pressurization device is that the eccentric shaft continues to rotate, the plunger moves to compress the fluid, and when the pressure in the cavity exceeds the spring force of the outlet cock, the outlet cock is opened, and the high-pressure fluid is discharged. The value of the spring force of the outlet cock is the target fluid pressure after the fluid pressurization device pressurizes the liquid.

[0054] A schematic diagram of a flow regulation control device is shown in Figure 2 , in which Figure 2In the diagram, 1 represents the flow controller, 2 represents the flow regulating valve, 3 represents the pump body, 4 represents the return water pipe of the radiator in the housing, 5 represents the inlet water pipe of the radiator in the housing, 6 represents the return water pipe of the housing, 7 represents the housing, 8 represents the outlet water pipe of the housing, 9 represents the wiring terminal, 10 represents the fluid inlet, and 11 represents the fluid outlet.

[0055] A schematic diagram of the fluid booster device is shown below. Figure 3 As shown, in Figure 3 In the diagram, 10 represents the fluid inlet, 11 represents the fluid outlet, 12 represents the eccentric shaft with an internal magnet, 13 represents the pump front cover, 14 represents the plunger, 15 represents the plunger baffle, 16 represents the baffle cavity, 17 represents the pump body, 18 represents the pump rear cover, 19 represents the rear bearing cover, 20 represents the booster chamber, 21 represents the double vane, 22 represents the stator coil assembly, and 23 represents the front bearing cover. It can be understood that the pump housing 17 has a fluid outlet 11 and a fluid inlet 10, and the pump body 17 has a booster chamber 20 communicating with the two fluid inlets / outlets 11 and 10; a plunger 14 coaxially connected to the booster chamber 20 is rotatably connected to the pump body 17; an eccentric shaft with an internal magnet 14 located within the booster chamber 20 is fixedly sleeved on the plunger 14; and the plunger located within the booster chamber 20 is coaxially mounted on the eccentric shaft 14 with the internal magnet. 14. Both the pressurizing chamber 20 and the plunger 14 are cylindrical. A plunger baffle 15 is provided inside the pump body 17 between two fluid inlets / outlets 11 and 10. Double sliding vanes 21 are attached to both sides of the plunger baffle, and the double sliding vanes 21 are coaxial with the baffle cavity 16. The plunger baffle 15 is connected to the outside of the plunger 14 and guides the plunger to move along the eccentric shaft 12 of the built-in magnet within the pressurizing chamber 20. One outer side of the plunger 14 is attached to the inner wall of the pressurizing chamber 20. A front pump cover 13 and a rear pump cover 18 are installed at the front and rear positions of the pump body 17.

[0056] A schematic diagram of the part of the motor rotor driving the booster chamber to compress fluid is shown below. Figure 4 As shown, in Figure 4 In the diagram, 9 represents the terminal block, 12 represents the eccentric shaft with the built-in magnet, 22 represents the stator coil assembly, 24 represents the shaft end cooling water inlet, 25 represents the powerful magnet, and 26 represents the shaft end cooling water outlet.

[0057] When the pressure of the fluid outlet is greater than the pressure of the fluid inlet, the tank radiator inlet pipe 5 and the fluid outlet 11 are communicated, the tank radiator outlet pipe 4 and the fluid inlet 10 are communicated, and the flow regulating valve 2 is installed on the tank radiator inlet pipe 5; the shaft of the stator coil assembly 22 is hollow, and the two ends of the stator coil assembly 22 and the tank outlet pipe 8 and the tank outlet pipe 6 of the tank 7 are connected to form a closed loop; the tank 7 is filled with antifreeze. Normally, the flow regulating valve 2 is in an open state, and the flow is small. Because the pressure of the fluid outlet is greater than the pressure of the fluid inlet, a small amount of water flows through the radiator to cool the antifreeze, and the antifreeze carries away the heat of the main shaft. When the flow controller detects that the water fluid outlet pressure increases, the flow regulating valve 2 opens to increase the flow to the radiator, thereby reducing the fluid outlet pressure, thereby improving the heat dissipation of the main shaft motor. Such a cycle makes the water pump maintain a constant pressure for a long time.

[0058] A pressure sensor is installed at the inlet position of the fluid pressurizing device, that is, a pressure sensor is installed at the position corresponding to 10 in Figure 2 The pressure sensor is used to monitor the fluid inlet pressure. Because the inlet position of the fluid pressurizing device is connected to the pump, the fluid inlet pressure can be used to reflect the power of the pump.

[0059] A pressure sensor is installed at the outlet position of the fluid pressurizing device, that is, a pressure sensor is installed at the position corresponding to 11 in Figure 2 The pressure sensor is used to monitor the fluid outlet pressure of the fluid pressurizing device, that is, the pressure of the fluid after being pressurized.

[0060] An eddy current displacement sensor is used to collect the rotating speed of the eccentric shaft of the fluid pressurizing device. The rotating speed of the eccentric shaft can be adjusted by a servo motor.

[0061] Preferably, in one embodiment of the present application, when collecting the fluid inlet pressure, the fluid outlet pressure, and the rotating speed of the eccentric shaft of the fluid pressurizing device, the embodiment takes 3 seconds as a collection period, and the sampling frequency is 50 Hz. In actual application, as other implementation manners, the implementer can determine the length of the collection period according to actual conditions, and the present application does not make special limitations. It can be understood that the rotating speed of the eccentric shaft is fixed. Because the target fluid pressure after being pressurized by the fluid pressurizing device is pre-set, the length of time for completing a complete pressurizing process is also determined, and the length of time for obtaining the pressurizing process is obtained.

[0062] Thus, the fluid inlet pressure, the fluid outlet pressure, the rotating speed of the eccentric shaft, and the length of time for the pressurizing process of the fluid pressurizing device are obtained.

[0063] Step S002, determining the cavitation possibility of the same pressurization process according to the difference between the ideal pressurization process and the change trend of all fluid inlet pressures collected in the same pressurization process, determining the pressurization cavitation possibility of the collection period according to the change trend of the cavitation possibilities of all pressurization processes in the collection period and the difference between the fitting curves of all pressurization processes, and determining whether to adjust the rotation speed and pump of the fluid pressurizing device according to the pressurization cavitation possibility of the collection period.

[0064] When the fluid flows through narrow pipes, throttles, valves and other positions during the pressurization process, the flow rate increases sharply, resulting in a decrease in fluid pressure. According to Bernoulli's equation, the increase in flow rate will cause the fluid pressure to decrease, and when the fluid pressure decreases below the air separation pressure, the air dissolved in the fluid will rapidly separate out to form a large number of bubbles, resulting in cavitation. The air separation pressure is the critical pressure at which the dissolved air in the liquid begins to separate from the liquid. When cavitation occurs during the fluid pressurization process, if the pressure of the fluid pressurizing device is not effectively and timely adjusted, it will easily lead to fatigue failure of the components of the fluid pressurizing device, shorten the service life, damage the sealing elements, and other problems, affecting the normal operation of the fluid pressurizing device. Therefore, when cavitation occurs, the device needs to be controlled in time to ensure the stability and safety of the pressurization process.

[0065] During the normal pressurization process of the fluid pressurizing device, the servo motor provides power to ensure the uniform rotation of the eccentric shaft, and the plunger moves uniformly on the slider. After completing a pressurization process, the plunger moves to the left, and the fluid enters the cavity from the inlet to continue the next pressurization process. Therefore, the pressurization process is periodic, and the change of the fluid inlet pressure is synchronized with the movement of the plunger of the fluid pressurizing device, and the fluid inlet pressure presents a periodic sinusoidal wave. If cavitation occurs during the pressurization process of the fluid pressurizing device, a large number of bubbles are formed to occupy part of the effective volume of the cavity. Because the gas has better compressibility than the liquid, the pressure increase speed is slowed down during the compression stroke of the plunger, and the peak value of the fluid inlet pressure is reduced. Further, when the large number of bubbles formed are broken, a local high pressure impact is generated, causing the change trend of the fluid inlet pressure to appear a significant fluctuation in the form of a sawtooth shape. Therefore, when cavitation occurs, the fluid inlet pressure will have a significant difference from the periodic sinusoidal wave, and the possibility of cavitation during the pressurization process can be determined according to the difference between the change trend of the fluid inlet pressure and the sinusoidal curve.

[0066] The sinusoidal function is used to curve fit all fluid inlet pressures collected in the same pressurization process in the collection period to obtain a fitting curve of the fluid inlet pressure in the same pressurization process. The fitting value of the collection time corresponding to all fluid inlet pressures in the same pressurization process is obtained according to the fitting curve, and the fitting value is the ideal value of the fluid inlet pressure at the corresponding collection time. The difference between the fluid inlet pressure and the fitting value at the same collection time is recorded as the fitting error at the same collection time. The collection time corresponding to the maximum value of all fluid inlet pressures collected in the same pressurization process is recorded as the peak time of the same pressurization process.

[0067] In this embodiment, the least square method is used for curve fitting. The least square method for curve fitting is a known technology and will not be described again. In actual application, as other embodiments, the implementer can use other methods to fit the curve on the basis of achieving the purpose of curve fitting, and the present application does not make special limitation.

[0068] According to the difference between the fitting values of all collection times in the pressurization process, the possibility of cavitation phenomenon in the pressurization process is determined.

[0069] Preferably, as an embodiment of the present application, the product of the absolute value of the fitting error at the peak time of the pressurization process and the standard deviation of the fitting values of all collection times in the pressurization process is recorded as the possibility of cavitation phenomenon in the pressurization process.

[0070] The fitting error at the peak time of the pressurization process is the difference between the peak value of the fluid inlet pressure and the peak value of the fitting curve of the pressurization process. When the absolute value of the fitting error at the peak time of the pressurization process is larger, the possibility of the pressure increasing speed slowing down in the plunger compression stroke due to the cavitation phenomenon is larger, and the possibility of the cavitation phenomenon is larger. When the standard deviation of the fitting values of all collection times in the pressurization process is larger, the possibility of the local high pressure impact caused by the collapse of a large number of bubbles formed by the cavitation phenomenon is larger, and the possibility of the cavitation phenomenon is larger. The possibility of cavitation phenomenon in the pressurization process is used to evaluate the possibility of the cavitation phenomenon in the pressurization process. When the product of the absolute value of the fitting error at the peak time of the pressurization process and the standard deviation of the fitting values of all collection times in the pressurization process is larger, the possibility of the cavitation phenomenon in the pressurization process is larger, and the possibility of the cavitation phenomenon in the pressurization process is larger.

[0071] The flow chart of obtaining the possibility of cavitation phenomenon is shown in Figure 5 .

[0072] The cavitation phenomenon is caused by the mismatch between the pressure and the actual pressurization pressure that the pressurization fluid can withstand in the pressurization process. Therefore, when the cavitation phenomenon occurs in the pressurization process, the cavitation phenomenon will occur in a plurality of continuous pressurization processes, and the cavitation phenomenon may become more and more serious.

[0073] The supercharging cavitation possibility of the collection period is determined according to the variation trend of the cavitation possibility of all supercharging processes in the collection period and the difference between the fitting curves of all supercharging processes.

[0074] The cavitation possibilities of all supercharging processes in the collection period are arranged in the order of the supercharging processes, the order corresponding to the cavitation possibilities is taken as the independent variable, the cavitation possibilities are taken as the dependent variable, the cavitation possibilities are linearly fitted, and the slope of the fitting straight line of the collection period is obtained.

[0075] The slope of the fitting straight line of the collection period is used to evaluate the variation trend of the values of the cavitation phenomena of all supercharging processes in the collection period. In this embodiment, the least square method is used for linear fitting, and the least square method for linear fitting is a known technology and will not be described in detail. In actual application, as other embodiments, on the basis of achieving the purpose of linear fitting, the implementer can use other methods of existing technologies such as polynomial fitting technology to fit the curve, and the present application does not make special limitation.

[0076] The sum of the Fréchet distances between the fitting curves of all supercharging processes in the collection period is recorded as the supercharging process difference of the collection period, and the normalized value of the product of the mean value of the cavitation possibilities of all supercharging processes in the collection period, the slope of the fitting straight line of the collection period, and the supercharging process difference of the collection period is recorded as the supercharging cavitation possibility of the collection period.

[0077] It should be noted that the Z-Score standard normalization method is used to calculate the normalized value in this embodiment, and other methods of existing technologies such as maximum and minimum value normalization method, sigmoid function, etc. can be used to calculate the normalized value in actual application, which is not limited herein. Preferably, the calculation of the Fréchet distance between the curves and the calculation of the normalized value are known technologies and will not be described in detail.

[0078] The first cavitation threshold b1 and the second cavitation threshold b2 are set, wherein the first cavitation threshold is smaller than the second cavitation threshold, the value of the first cavitation threshold b1 in this embodiment is 0.1, and the value of the second cavitation threshold b2 is 0.9.

[0079] When the supercharging cavitation possibility of the collection period is less than the first cavitation threshold b1, it is determined that the fluid supercharging device is in normal operation, and no adjustment is needed for the fluid supercharging device; when the supercharging cavitation possibility of the collection period is greater than the second cavitation threshold b2, it is determined that there is a serious cavitation phenomenon in the fluid supercharging device, at this time, only the eccentric shaft speed of the fluid supercharging device is adjusted, and the cavitation phenomenon in the supercharging process cannot be effectively improved, and the energy transmission efficiency is further reduced, the pump of the fluid supercharging device is sent an adjustment instruction, and the pump is adjusted to realize pressure control; when the supercharging cavitation possibility of the collection period is greater than or equal to the first cavitation threshold b1 and less than or equal to the second cavitation threshold b2, it is determined that there is a cavitation phenomenon in the fluid supercharging device, and the cavitation phenomenon is within the range that can be regulated by the fluid supercharging device, and the speed of the fluid supercharging device is adjusted.

[0080] Among them, sending an adjustment instruction to the pump of the fluid supercharging device to adjust the pump to realize pressure control is a known technology, and will not be described again.

[0081] At this point, the judgment result of whether to adjust the speed and the pump of the fluid supercharging device is obtained.

[0082] Step S003, for the fluid supercharging device that needs to adjust the speed, the eccentric shaft adjustment speed of the collection period is determined according to the supercharging cavitation possibility of the collection period, the fluid outlet pressure collected in the collection period and the speed of the eccentric shaft, the speed of the eccentric shaft is regulated according to the eccentric shaft adjustment speed of the collection period, and the second judgment result of whether to adjust the speed and the pump of the fluid supercharging device is determined according to the difference between the eccentric shaft adjustment speed of the collection period and the speed of the eccentric shaft at the last collection time in the collection period.

[0083] For the fluid supercharging device that needs to adjust the speed, in order to reduce the impact of the local high pressure impact caused by the cavitation phenomenon in the supercharging process on the fluid supercharging device, avoid the continuous occurrence of the cavitation phenomenon, the speed of the eccentric shaft of the fluid supercharging device needs to be reduced to prolong the plunger suction time, reduce the volume change of the cavity, avoid the sudden change of the cavity volume caused by the bubble burst, and avoid the sudden change of the instantaneous pressure of the fluid, and when the cavitation phenomenon is more significant, the adjustment range of the speed of the eccentric shaft of the fluid supercharging device is larger. At the same time, when the target fluid pressure of the fluid supercharging device after supercharging the liquid is greater relative to the fluid outlet pressure of the fluid supercharging device, more plunger suction time needs to be prolonged to ensure that the fluid pressure in the cavity of the fluid supercharging device is sufficient.

[0084] For the fluid supercharging device that needs to adjust the speed, the eccentric shaft adjustment speed of the collection period is determined according to the supercharging cavitation possibility of the collection period, the fluid outlet pressure collected in the collection period and the speed of the eccentric shaft.

[0085] Specifically, the normalized value of the reciprocal of the difference between the probability of pressurization cavitation in the acquisition cycle and the first cavitation threshold is recorded as the first normalized value of the acquisition cycle; the average value of the fluid outlet pressure at the last acquisition moment of all pressurization processes acquired in the acquisition cycle is recorded as the actual pressurization of the acquisition cycle; the ratio of the actual pressurization of the acquisition cycle to the target fluid pressure after liquid pressurization is recorded as the first ratio of the acquisition cycle; and the product of the first normalized value, the first ratio, and the rotational speed of the eccentric shaft at the last acquisition moment in the acquisition cycle is recorded as the eccentric shaft adjustment speed of the acquisition cycle.

[0086] The rounded value of the eccentric shaft adjustment speed during the acquisition cycle is used as the value of the eccentric shaft speed after the acquisition cycle. Based on the difference between the eccentric shaft adjustment speed during the acquisition cycle and the eccentric shaft speed at the last acquisition moment within the acquisition cycle, a secondary judgment result is made to determine whether the speed of the fluid booster device and the pump should be adjusted.

[0087] The absolute value of the difference between the rotational speed of the eccentric shaft at the last acquisition moment within the acquisition cycle and the adjusted rotational speed of the eccentric shaft during the acquisition cycle is recorded as the first difference of the acquisition cycle. The ratio of the first difference of the acquisition cycle to the rotational speed of the eccentric shaft at the last acquisition moment within the acquisition cycle is recorded as the rotational speed change rate of the acquisition cycle.

[0088] A third cavitation threshold b3 is set, wherein in this embodiment, the value of the third cavitation threshold b3 is 2%.

[0089] When the rotational speed change rate during the acquisition cycle is less than the third cavitation threshold b3, it is determined that the cavitation phenomenon in the fluid booster exceeds the control range of the fluid booster's rotational speed. Adjusting only the eccentric shaft speed of the fluid booster cannot effectively improve the cavitation phenomenon during the boosting process. Therefore, an adjustment command is sent to the pump of the fluid booster to adjust the pump and achieve pressure control.

[0090] When the rotational speed change rate during the acquisition period is greater than or equal to the third cavitation threshold b3, T seconds is taken as an adjustment period. The probability of cavitation boosting during the adjustment period is obtained in the same way as the probability of cavitation boosting during the acquisition period. Based on the probability of cavitation boosting during the adjustment period, a judgment result is obtained on whether to adjust the eccentric shaft speed and pump of the fluid boosting device.

[0091] Where T is a preset time threshold, and in this embodiment, the preset time threshold is set to 10.

[0092] When the determination result obtained based on the possibility of cavitation during the adjustment cycle is that the eccentric shaft speed of the fluid booster should be adjusted, the adjustment cycle is repeated, and the determination result of whether to adjust the eccentric shaft speed of the fluid booster and the pump is obtained based on the possibility of cavitation during the adjustment cycle.

[0093] When the determination result of the adjustment of the eccentric shaft rotating speed of the fluid pressurizing device and the pump is that no adjustment is made to the fluid pressurizing device and adjustment is made to the pump, no new adjustment period is selected. When the determination result of each adjustment period is that the eccentric shaft rotating speed of the fluid pressurizing device is adjusted, the selection of the adjustment period is stopped when the number of adjustment periods is 4.

[0094] At this point, the secondary determination result of whether to adjust the eccentric shaft rotating speed of the fluid pressurizing device and the pump is obtained.

[0095] In step S004, when the long-time adjustment of the eccentric shaft rotating speed occurs, the pressurization cavitation possibility and the rotating speed change rate of all adjustment periods are obtained, and the rotating speed of the eccentric shaft is controlled in combination with the rotating speed of the eccentric shaft of all adjustment periods until the determination result of the normal operation of the fluid pressurizing device is obtained.

[0096] When 4 adjustment periods are selected and the determination result of each adjustment period is that the eccentric shaft rotating speed of the fluid pressurizing device is adjusted, it is indicated that the cavitation phenomenon is within the controllable range of the eccentric shaft rotating speed adjustment of the fluid pressurizing device, but a long-time eccentric shaft rotating speed is needed to avoid the interference of the cavitation phenomenon to the fluid pressurizing device. This case is recorded as the long-time adjustment of the eccentric shaft rotating speed, and the rotating speed is further adjusted.

[0097] The pressurization cavitation possibility and the rotating speed change rate of all adjustment periods are obtained, the difference between the pressurization cavitation possibility of the adjustment period and the pressurization cavitation possibility of the previous adjacent adjustment period is recorded as the pressurization cavitation possibility change rate of the adjustment period. The rotating speed change rate is taken as the independent variable, and the pressurization cavitation possibility change rate is taken as the dependent variable. The pressurization cavitation possibility change rate and the rotating speed change rate of all adjustment periods are linearly fitted to obtain a first fitting straight line. The fitting value of the pressurization cavitation possibility change rate corresponding to the rotating speed change rate of the last adjustment period is calculated according to the first fitting straight line of the adjustment period, and the calculated fitting value is recorded as a first fitting value. A sequence formed by arranging the pressurization cavitation possibility change rates of all adjustment periods in the order of the adjustment periods is recorded as a first sequence, and a sequence formed by adding the first fitting value after the first sequence is recorded as a second sequence. A sequence formed by arranging the rotating speed change rates of all adjustment periods in the order of the adjustment periods is recorded as a third sequence, and a sequence formed by adding the rotating speed change rate of the last adjustment period after the third sequence is recorded as a fourth sequence. The Pearson correlation coefficient of the first sequence and the third sequence is recorded as a first correlation coefficient, the Pearson correlation coefficient of the second sequence and the fourth sequence is recorded as a second correlation coefficient, the difference between the first correlation coefficient and the second correlation coefficient is recorded as a correlation coefficient difference, and the power of the natural constant with the correlation coefficient difference as the exponent is recorded as a first exponential power.

[0098] The rotational speed change rate of the adjustment period is obtained in the same way as the rotational speed change rate of the acquisition period. When the adjustment period is the first adjustment period, the adjustment period has no previous adjacent adjustment period. The difference between the supercharging cavitation possibility of the adjustment period and the supercharging cavitation possibility of the previous adjacent acquisition period is recorded as the supercharging cavitation possibility change rate of the adjustment period.

[0099] The average of the rotational speeds of the eccentric shafts collected in the adjustment period is recorded as the average eccentric shaft rotational speed of the adjustment period. The supercharging cavitation possibility of all the adjustment periods and the average eccentric shaft rotational speed of the adjustment period are fitted to obtain a second fitting straight line. The fitting value of the average eccentric shaft rotational speed when the supercharging cavitation possibility is equal to the first cavitation threshold b1 is obtained according to the second fitting straight line. The calculated fitting value is recorded as the second fitting value.

[0100] The product of the first fitting value and the first exponential power and the second fitting value is recorded as the first numerator. The sum of the first exponential power and the number 1 is recorded as the first denominator. The ratio of the first numerator to the first denominator is recorded as the secondary eccentric shaft adjustment rotational speed of the last adjustment period. The secondary eccentric shaft adjustment rotational speed of the last adjustment period is used as the rotational speed of the eccentric shaft at each acquisition time after the last adjustment period.

[0101] After the last adjustment period, the adjustment period is repeatedly selected, and the rotational speed of the eccentric shaft is adjusted according to the secondary eccentric shaft adjustment rotational speed, until the determination result of the normal operation of the fluid pressurizing device is obtained.

[0102] Up to now, the fluid pressurizing device can realize self-adaptive pressure control.

[0103] The above only describes the preferred embodiments of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the principles of the present application shall be included in the protection scope of the present application.

Claims

1. An adaptive pressure-controlled fluid booster device, characterized in that, The device includes the following steps: The fluid inlet pressure, fluid outlet pressure, and eccentric shaft rotation speed of the fluid booster device are collected within a preset collection period to obtain the duration of the boosting process within the collection period. Based on the difference between the ideal pressurization process and the changing trends of all fluid inlet pressures collected during the same pressurization process, the probability of cavitation in the same pressurization process is determined. Based on the changing trends of the probability of cavitation in all pressurization processes within the collection period, and the differences between the fitted curves of all pressurization processes, the probability of pressurization cavitation in the collection period is determined. Based on the probability of pressurization cavitation in the collection period, it is determined whether to adjust the speed of the fluid pressurization device and the pump. For fluid booster devices that require speed adjustment, the eccentric shaft adjustment speed for the sampling period is determined based on the possibility of cavitation during the sampling period, the fluid outlet pressure collected during the sampling period, and the eccentric shaft speed. The eccentric shaft speed is then adjusted based on the eccentric shaft adjustment speed for the sampling period. Finally, a secondary judgment is made based on the difference between the eccentric shaft adjustment speed for the sampling period and the eccentric shaft speed at the last sampling moment within the sampling period to determine whether the eccentric shaft speed and pump of the fluid booster device should be adjusted. When the eccentric shaft speed is adjusted for a long period of time, the probability of cavitation and the rate of change of speed for all adjustment cycles are obtained. The speed of the eccentric shaft is controlled by combining the speed of the eccentric shaft for all adjustment cycles until the result of determining that the fluid booster device is operating normally is obtained.

2. The adaptive pressure control fluid booster device according to claim 1, characterized in that, The method for determining the probability of cavitation during the pressurization process is as follows: Curve fitting is performed on all fluid inlet pressures collected during the same pressurization process within the acquisition period to obtain the fitting curve of the fluid inlet pressure during the same pressurization process. Based on the fitting curve, the fitting value of the acquisition time corresponding to all fluid inlet pressures during the same pressurization process is obtained. The difference between the fluid inlet pressure at the same acquisition time and the fitting value is recorded as the fitting error at the same acquisition time. The time corresponding to the maximum value of all fluid inlet pressures collected during the same pressurization process is recorded as the peak time of the same pressurization process. The product of the absolute value of the fitting error at the peak moment of the pressurization process and the standard deviation of the fitting values ​​at all sampling moments during the pressurization process is denoted as the probability of cavitation during the pressurization process.

3. The adaptive pressure control fluid booster device according to claim 1, characterized in that, The method for obtaining the probability of pressurized cavitation during the collection period is as follows: The probability of cavitation during all pressurization processes in the acquisition period is arranged in the order of pressurization processes, and the probability of cavitation is fitted with a straight line to obtain the slope of the fitted straight line for the acquisition period. The sum of the Fraser distances between the fitted curves of all boosting processes within the acquisition period is denoted as the boosting process difference of the acquisition period. The normalized value of the product of the mean probability of cavitation in all pressurization processes within the acquisition period, the slope of the fitted line of the acquisition period, and the difference in pressurization processes within the acquisition period, is denoted as the pressurization cavitation probability of the acquisition period.

4. The adaptive pressure control fluid booster device according to claim 1, characterized in that, The specific method for determining whether to adjust the speed and pump of the fluid booster device based on the probability of cavitation during the collection period includes: When the probability of pressurization cavitation during the sampling period is less than the first cavitation threshold, the fluid pressurization device is not adjusted. When the probability of cavitation during the sampling period is greater than the second cavitation threshold, an adjustment command is sent to the pump of the fluid booster device to adjust the pump and achieve pressure control. When the probability of pressurization cavitation during the sampling period is greater than or equal to the first cavitation threshold and less than or equal to the second cavitation threshold, the rotation speed of the fluid pressurization device is adjusted. The first cavitation threshold and the second cavitation threshold are both preset thresholds, and the first cavitation threshold is less than the second cavitation threshold.

5. The adaptive pressure control fluid booster device according to claim 4, characterized in that, The method for determining the eccentric shaft adjustment speed during the acquisition cycle is as follows: The normalized value of the reciprocal of the difference between the probability of pressurized cavitation in the acquisition period and the first cavitation threshold is denoted as the first normalized value of the acquisition period. The average value of the fluid outlet pressure at the last acquisition moment of all pressurization processes acquired in the acquisition cycle is recorded as the actual pressurization of the acquisition cycle. The ratio of the actual pressurization of the acquisition cycle to the target fluid pressure after liquid pressurization is recorded as the first ratio of the acquisition cycle. The product of the first normalized value, the first ratio, and the rotational speed of the eccentric shaft at the last acquisition moment within the acquisition cycle is denoted as the eccentric shaft adjustment speed of the acquisition cycle.

6. The adaptive pressure control fluid booster device according to claim 1, characterized in that, The method for controlling the rotational speed of the eccentric shaft by adjusting its rotational speed according to the acquisition period includes the following specific methods: The rounded value of the eccentric shaft adjustment speed during the acquisition cycle is used as the value of the eccentric shaft speed after the acquisition cycle.

7. The adaptive pressure control fluid booster device according to claim 1, characterized in that, The secondary judgment result, which determines whether to adjust the eccentric shaft speed and pump of the fluid booster device based on the difference between the eccentric shaft adjustment speed during the acquisition cycle and the eccentric shaft speed at the last acquisition moment within the acquisition cycle, includes the following specific methods: The absolute value of the difference between the rotational speed of the eccentric shaft at the last acquisition moment in the acquisition cycle and the adjusted rotational speed of the eccentric shaft in the acquisition cycle is recorded as the first difference of the acquisition cycle. The ratio of the first difference of the acquisition cycle to the rotational speed of the eccentric shaft at the last acquisition moment in the acquisition cycle is recorded as the rotational speed change rate of the acquisition cycle. Based on the value of the rotational speed change rate during the acquisition period, a secondary judgment result is made to determine whether the eccentric shaft speed of the fluid booster device and the pump should be adjusted.

8. The adaptive pressure control fluid booster device according to claim 7, characterized in that, The secondary judgment result, which determines whether to adjust the eccentric shaft speed and pump of the fluid booster device based on the value of the rotational speed change rate during the acquisition period, includes the following specific methods: When the rate of change of rotational speed during the acquisition cycle is less than the third cavitation threshold, an adjustment command is sent to the pump of the fluid booster device to adjust the pump and achieve pressure control. When the rotational speed change rate during the acquisition period is greater than or equal to the third cavitation threshold, T seconds is taken as an adjustment period. The probability of pressurization cavitation during the adjustment period is obtained in the same way as the probability of pressurization cavitation during the acquisition period. Based on the probability of pressurization cavitation during the adjustment period, a judgment result is obtained on whether to adjust the eccentric shaft speed and pump of the fluid pressurization device. Here, T is a preset time threshold.

9. The adaptive pressure control fluid booster device according to claim 1, characterized in that, The specific details of adjusting the eccentric shaft speed over a long period of time are as follows: Four consecutive adjustment cycles were selected, and the judgment result corresponding to each adjustment cycle was to adjust the eccentric shaft speed of the fluid booster device.

10. The adaptive pressure control fluid booster device according to claim 4, characterized in that, The method for controlling the rotational speed of the eccentric shaft by combining the rotational speeds of the eccentric shafts across all adjustment cycles includes the following specific methods: The difference between the probability of cavitation in the adjustment cycle and the probability of cavitation in the previous adjacent adjustment cycle is denoted as the rate of change of the probability of cavitation in the adjustment cycle. A linear fit is performed on the rate of change of the probability of cavitation in all adjustment cycles and the rate of change of speed to obtain the first fitted line. Based on the first fitted line of the adjustment cycle, the fitted value of the rate of change of the probability of cavitation in the last adjustment cycle corresponding to the rate of change of speed is calculated and denoted as the first fitted value. The sequence formed by arranging the possible changes in boost cavitation probability of all adjustment cycles in chronological order is denoted as the first sequence. The sequence formed by adding the first fitted value to the first sequence is denoted as the second sequence. The sequence formed by arranging the possible changes in rotational speed of all adjustment cycles in chronological order is denoted as the third sequence. The sequence formed by adding the rotational speed change rate of the last adjustment cycle to the third sequence is denoted as the fourth sequence. The correlation coefficient between the first and third sequences is denoted as the first correlation coefficient. The correlation coefficient between the second and fourth sequences is denoted as the second correlation coefficient. The difference between the first and second correlation coefficients is denoted as the correlation coefficient difference. The power of the correlation coefficient difference with the natural constant as the base is denoted as the first exponent. The average rotational speed of all eccentric shafts collected during the adjustment cycle is recorded as the average rotational speed of the eccentric shaft during the adjustment cycle. The probability of cavitation during the boosting cycle is fitted to the average rotational speed of the eccentric shaft during the adjustment cycle to obtain a second fitting line. Based on the second fitting line, the fitted value of the average rotational speed of the eccentric shaft when the probability of cavitation during the boosting cycle is the first cavitation threshold is obtained and recorded as the second fitted value. The product of the first fitted value and the first exponent, plus the sum of the second fitted value, is recorded as the first numerator. The sum of the first exponent and the number 1 is recorded as the first denominator. The ratio of the first numerator to the first denominator is recorded as the second eccentric shaft adjustment speed in the last adjustment cycle. The second eccentric shaft adjustment speed in the last adjustment cycle is used as the eccentric shaft speed at each acquisition time after the last adjustment cycle.

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