CN114962200B - Multiple frequency cam digital pump - Google Patents

Multiple frequency cam digital pump Download PDF

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Publication number
CN114962200B
CN114962200B CN202210513634.1A CN202210513634A CN114962200B CN 114962200 B CN114962200 B CN 114962200B CN 202210513634 A CN202210513634 A CN 202210513634A CN 114962200 B CN114962200 B CN 114962200B
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plunger
cam
multiple frequency
pressure oil
digital
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CN114962200A (en
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姚英学
程碧懿
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Shenzhen Graduate School Harbin Institute of Technology
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Shenzhen Graduate School Harbin Institute of Technology
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
    • F04B1/053—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement with actuating or actuated elements at the inner ends of the cylinders
    • F04B1/0531—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement with actuating or actuated elements at the inner ends of the cylinders with cam-actuated distribution members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
    • F04B1/0404—Details or component parts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/10—Valves; Arrangement of valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/14—Pistons, piston-rods or piston-rod connections
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/14—Pistons, piston-rods or piston-rod connections
    • F04B53/144—Adaptation of piston-rods
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/16—Casings; Cylinders; Cylinder liners or heads; Fluid connections
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/16—Casings; Cylinders; Cylinder liners or heads; Fluid connections
    • F04B53/162—Adaptations of cylinders
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P80/00—Climate change mitigation technologies for sector-wide applications
    • Y02P80/10—Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)

Abstract

The invention relates to the technical field of hydraulic pressure of mechanical engineering, in particular to a multiple frequency cam digital pump, which comprises a cam, wherein a plurality of plunger units are uniformly distributed on the circumference of the cam, the cam drives the plunger units to finish oil suction and discharge, each plunger unit is provided with a digital flow distribution valve, each digital flow distribution valve is controlled to be communicated with a high-pressure oil way or a low-pressure oil way through binary coding, the binary coding control part plunger units are connected with the high-pressure oil way, the binary coding is signals '0' and '1', when a plunger rod is in a return state, the signal '0' controls a high-speed electromagnetic valve to be opened, and the signal '1' controls the high-speed electromagnetic valve to be closed; the problems of abrasion and failure of the conventional gear speed increasing box caused by abrupt load and limit load can be solved; the binary coding flow control strategy of the digital pump realizes the flow stability and continuity of energy conversion of the ultra-large wind power generator.

Description

Multiple frequency cam digital pump
Technical Field
The invention relates to the technical field of hydraulic pressure of mechanical engineering, in particular to a multiple frequency cam digital pump.
Background
The hydraulic transmission system has the outstanding advantages of high power density, high limit working parameters, high response frequency and the like, and is widely applied in various industrial fields. The hydraulic acceleration technology is one of important technologies in the wind power field, and can solve a plurality of problems of the mechanical acceleration technology. The low-speed high-power cam-plunger unit adopting the digital flow distribution valve is one of core components of the wind power hydraulic speed increasing system. When the random wind speed of time-varying input pushes the wind wheel of the wind turbine to rotate, the control system taking the rotating speed of the cam as a clock signal dynamically adjusts the working state of each plunger according to wind speed information, and the change of the displacement of the digital pump is realized. Meanwhile, when the displacement of the pump is changed, the reaction moment of the pump acting on the wind wheel is correspondingly changed, so that the rotating speed of the wind wheel is changed along with wind energy, the tip speed ratio of the wind turbine is maintained at an optimal value, and the maximum power tracking of wind energy is realized; the control system dynamically adjusts the displacement of the energy accumulator and the hydraulic motor according to the outlet flow of the plunger unit, and maintains the constant electric energy frequency.
The digital pump concept breaks through the linkage constraint relation among the oil sucking and discharging plunger units in the traditional swash plate type plunger units in structural principle, each plunger unit realizes independent oil sucking and discharging flow distribution through a group of high-speed electromagnetic valves, and the plunger units which do not need to do work can be unloaded in real time, so that the narrow problem of the high-efficiency area of the traditional hydraulic pump can be thoroughly overcome, the variable displacement control advantage is achieved, the front development direction of the hydraulic pump with great potential is represented, and the hydraulic pump is a research hotspot and focus of attention in the industry.
The recognition modeling of the pressure transient law in the plunger unit and the outlet flow pulsation law of the digital pump is known from the variable speed constant frequency control principle of wind power hydraulic transmission and is the basis of hydraulic wind turbine control. The dynamic characteristic is the basis for researching the performance of the wind generating set, and the digital pump is a system consisting of a plurality of plungers and a plurality of distributing valves, and in the working process of the digital pump, complex mechanical-hydraulic coupling phenomenon exists among a driving cam, an acting plunger, a hydraulic medium and the digital distributing valves. The performance of the digital pump is greatly limited by the performance of a high-speed electromagnetic valve product, the frequency response of the high-speed electromagnetic valve determines the rotating speed range and variable dynamic performance which can be achieved by the digital pump, the flow capacity of the high-speed electromagnetic valve determines the oil sucking and discharging flow of each plunger unit of the digital pump, meanwhile, the electric power loss required by driving the high-speed electromagnetic valve and the throttling loss of a valve port also have obvious influence on the efficiency characteristic of the digital pump, and the key performance of an energy transmission system of a wind generating set is closely related to the displacement setting of a flow distribution valve of the digital pump and the flow distribution control strategy of the digital pump; the conventional gear speed increasing box in the prior art has the problems of abrasion and failure caused by abrupt load and limit load, and can not ensure the flow stability and continuity of energy conversion of the wind power generator under the condition of wind power change.
Disclosure of Invention
The invention aims to provide a multiple frequency cam digital pump which can solve the problems of abrasion and failure of a conventional gear speed increasing box caused by abrupt load and limit load; the binary coded flow control strategy of the digital pump realizes the flow stability and continuity of energy conversion of the wind power generator.
The aim of the invention is achieved by the following technical scheme:
the multiple frequency cam digital pump comprises a cam, wherein a plurality of plunger units are uniformly distributed on the surface of the cam in the circumferential direction, the cam drives the plunger units to finish the oil suction-discharge process in a rotating way, each plunger unit is provided with a digital flow distribution valve, each digital flow distribution valve is controlled to be communicated with a high-pressure oil way or a low-pressure oil way through binary coding, and the binary coding control part plunger units are connected with the high-pressure oil way;
the surface of the cam is provided with a multiple frequency cam curve profile, the multiple frequency cam curve is a trigonometric function curve, an interpolation curve or a fitting curve, and the multiple frequency cam curve profile is provided with a plurality of lift-return cycles;
the plunger unit comprises a plunger seat, a plunger rod is slidably connected to the plunger seat, a first roller and a second roller are rotatably connected to the plunger rod, and the first roller and the second roller are contacted with the curve profile of the multiple frequency cam;
the digital flow distribution valve comprises a high-speed electromagnetic valve, a one-way valve, an oil inlet passage port and an oil discharge passage port, wherein the oil inlet passage port is communicated with the plunger seat, the oil discharge passage port is provided with two outlet ends, one outlet end of the oil discharge passage port is connected with a high-pressure oil way, the other outlet end of the oil discharge passage port is communicated with a low-pressure oil way, the one-way valve is arranged in the outlet end connected with the high-pressure oil way, and the high-speed electromagnetic valve is arranged in the outlet end of the low-pressure oil way;
the binary codes are signals '0' and '1', when the plunger rod is in a return state, the signal '0' controls the high-speed electromagnetic valve to be opened, hydraulic medium discharged by the plunger seat is discharged into a low-pressure oil way through the high-speed electromagnetic valve, the signal '1' controls the high-speed electromagnetic valve to be closed, and the hydraulic medium discharged by the plunger seat is discharged into the high-pressure oil way through the one-way valve;
the plurality of plunger units are fixedly connected to the tower, the cams are fixedly connected with the wind wheel and rotate together, and the tower is used for supporting and fixing the plurality of plunger seats;
the invention has the beneficial effects that;
the multiple frequency cam digital pump realizes the acceleration and energy conversion of the wind wheel of the ultra-large wind driven generator, solves the problems of abrasion and failure of a conventional gear speed increasing box caused by abrupt load and limit load, can reduce the failure rate and the overall cost of the ultra-large wind driven generator, and prolongs the service life of an energy transmission system of the ultra-large wind driven generator; the high-speed electromagnetic valve and the one-way valve are adopted to carry out digital flow distribution, so that the efficiency of the digital pump under the unbalanced load condition is improved, a plurality of plunger units with consistent power are circumferentially distributed along the cam rotating shaft, and the transmission power can be increased by times; the invention is suitable for both vertical axis wind driven generators and horizontal axis wind driven generators, and the binary coded flow control strategy of the digital pump realizes the flow stability and continuity of energy conversion of the ultra-large wind driven generator.
Drawings
The invention will be described in further detail with reference to the accompanying drawings and detailed description.
FIG. 1 is a schematic diagram of a multiple frequency cam digital pump of the present invention;
FIG. 2 is a schematic diagram of the principle of the multiple frequency cam axial digital pump of the present invention for a horizontal axis wind turbine;
FIG. 3 is a schematic diagram II of the multiple frequency cam axial digital pump of the present invention for a horizontal axis wind turbine;
FIG. 4 is a schematic diagram of the principle of the multiple frequency cam radial digital pump of the present invention for a vertical axis wind turbine;
FIG. 5 is a schematic diagram II of the multiple frequency cam radial digital pump of the present invention for a vertical axis wind turbine;
FIG. 6 is a schematic diagram III of the multiple frequency cam radial digital pump of the present invention for a vertical axis wind turbine;
FIG. 7 is a schematic illustration of the differential displacement coefficient 6 cylinder superimposed displacement fluctuation of the present invention;
FIG. 8 is a graphical illustration of displacement factor minimum resolution comparisons of the present invention.
In the figure: a digital distribution valve 1; a first roller 2; a second roller 3; a plunger rod 4; a plunger holder 5; a tower 6; and a cam 7.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings.
As shown in fig. 1 to 6, wherein fig. 2 and 3 are schematic diagrams of a multiple frequency cam axial digital pump for a horizontal axis wind turbine, and fig. 4 to 6 are schematic diagrams of a multiple frequency cam radial digital pump for a vertical axis wind turbine;
in order to solve the technical problem of how to realize the flow stability and continuity of energy conversion of the wind power generator, the structure and the function of a multiple frequency cam digital pump are described in detail below;
the multiple frequency cam digital pump comprises a digital flow distribution valve 1, plunger units, a tower 6 and a cam 7, wherein the tower 6 is a wind turbine tower, a plurality of plunger units are arranged, the plunger units are distributed in the tower 6, the cam 7 is connected with a wind wheel, the plunger units are driven to rotate to complete the oil absorption-oil discharge process, each plunger unit is provided with the digital flow distribution valve 1, each digital flow distribution valve 1 is controlled to be communicated with a high-pressure oil way or a low-pressure oil way through binary coding, and a binary coding control part is connected with the plunger units and the high-pressure oil way;
when the wind power is changed, when the wind power is increased, the plunger units with more binary codes are communicated with the high-pressure oil circuit, and when the wind power is reduced, the plunger units with less binary codes are communicated with the high-pressure oil circuit, so that the same oil pressure output by the plunger units is ensured, and the flow stability and the continuity of energy conversion of the wind power generator are ensured;
the design of the multiple frequency cam digital pump realizes that the plunger unit has a plurality of oil sucking and discharging periods in one cam 7 rotation period, realizes the speed increasing function of a hydraulic transmission system, reduces the impact and vibration of the cam 7 and the plunger unit, and solves the inter-restriction relation between the valve response speed and the valve opening size by a binary coded flow control strategy;
the plunger unit comprises a first roller 2, a second roller 3, a plunger rod 4 and a plunger seat 5, wherein the plunger rod 4 is connected in a sliding way in the plunger seat 5, the first roller 2 and the second roller 3 are connected on the plunger rod 4 in a rotating way, the rotating connection can be realized through a bearing and a clamp spring, the first roller 2 and the second roller 3 are contacted with the curve profile of the multiple frequency cam, and the double roller contact form of the first roller 2 and the second roller 3 is beneficial to reducing abrasion;
the cam 7 is connected with the vertical axis wind turbine blade through a supporting arm and is rigidly connected with the horizontal axis wind turbine rotating shaft, the cam 7 is an energy input element of a hydraulic system, the surface of the cam 7 is provided with a multiple frequency cam curve profile, the multiple frequency cam curve comprises but not limited to a trigonometric function curve, an interpolation curve or a fitting curve, and the multiple frequency cam curve profile is provided with a plurality of lift-return cycles;
the lift-return cycle of the profile curve of the cam 7 and the suction-discharge cycle of the plunger unit are expressed as (1).
N=k, where K > 1 (1)
The cam 7 rotates under the drive of wind force, the cam 7 drives the plunger rods 4 to move through a multi-frequency cam curve profile arranged on the cam 7, so that the plunger rods 4 reciprocate in the plunger seat 5, the multi-frequency cam curve profile is provided with a plurality of lift-return cycles, and the cam 7 can drive the plunger rods 4 to reciprocate in the plunger seat 5 for a plurality of times in one rotation cycle, so that the rotation motion of the wind turbine is converted into the linear motion of the plunger rods;
the digital flow distribution valve 1 comprises a high-speed electromagnetic valve, a one-way valve, an oil inlet passage port and an oil discharge passage port, wherein the oil inlet passage port is communicated with the plunger seat 5, the oil discharge passage port is provided with two outlet ends, one outlet end of the oil discharge passage port is connected with a high-pressure oil path, the other outlet end of the oil discharge passage port is communicated with a low-pressure oil path, the one-way valve is arranged in the outlet end connected with the high-pressure oil path, the high-speed electromagnetic valve is arranged in the outlet end of the low-pressure oil path, when the cam 7 drives the plunger rod 4 to be in a lift state, the plunger rod 4 slides in the plunger seat 5, a hydraulic cavity in the plunger seat 5 is increased, and a hydraulic medium enters the plunger seat 5 through the oil inlet passage port, wherein the hydraulic medium is hydraulic oil;
the binary codes are signals '0' and '1', when the cam 7 drives the plunger rod 4 to be in a return state, the plunger rod 4 extrudes a hydraulic medium in the plunger seat 5, when the high-speed electromagnetic valve receives the signal '0', the signal '0' controls the high-speed electromagnetic valve to be opened, the hydraulic medium discharged by the plunger seat 5 is discharged into a low-pressure oil path through the high-speed electromagnetic valve, and at the moment, the plunger unit is in an 'unloading' state or an 'idle' state;
when the high-speed electromagnetic valve receives the signal '1', the signal '1' controls the high-speed electromagnetic valve to be closed, and hydraulic medium discharged by the plunger seat 5 is discharged into a high-pressure oil way through the one-way valve, and the plunger cylinder is in a 'working' state at the moment;
defining the flow coefficient f as the ratio of the effective flow rate to the maximum flow rate of the digital pump in the "working" state, as shown in the following formula (2):
Figure BDA0003638767020000061
wherein Q is less than or equal to Q p (2)
According to the flow control rule of binary coding, a specific number of plunger units are connected into a high-pressure oil way, a high-speed electromagnetic valve and a one-way valve are adopted to carry out digital flow distribution, the efficiency of a digital pump under the unbalanced load condition is improved, a plurality of plunger units with consistent power are circumferentially distributed along the rotating shaft of the cam 7, the transmission power can be increased in multiple times, the plunger units reciprocate under the drive of the multiple frequency curve profile on the surface of the cam 7 according to a given motion rule, the oil absorption and the oil discharge are realized for multiple times in one circle of rotation of the rotating shaft of the wind wheel, the wind energy is converted into hydraulic energy, and the low-speed high-power energy transmission and conversion are realized;
the displacement, speed and acceleration equations of the profile curve of the cam 7 are respectively shown in the following formulas (3), (4) and (5), wherein K is the lift-return cycle of the cam curve, and i is the number of plunger units;
Figure BDA0003638767020000062
Figure BDA0003638767020000063
Figure BDA0003638767020000064
the theoretical flow rate of the i-th plunger unit in stable operation is shown in the following formula (6), wherein N is the oil suction-discharge period of the plunger unit, and A is the acting area of the plunger.
Figure BDA0003638767020000065
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Meanwhile, the volume of a working cavity formed in the digital pump is continuously and periodically changed from large to small and from small to large, the working cavity is minimum when the outer edges of the first roller 2 and the second roller 3 of the digital pump are positioned at the lowest point of the surface motion curve of the cam 7, the working cavity is maximum when the outer edges of the first roller 2 and the second roller 3 of the digital pump are positioned at the highest point of the surface motion curve of the cam 7, when the working cavity is changed from small to large, the hydraulic medium is sucked, and when the working cavity is changed from large to small, the hydraulic medium is discharged;
for the congruent flow combined plunger unit combination, the total flow of the digital pump is shown in the following formula (7), wherein the total flow is a control signal of the digital distributing valve corresponding to the ith plunger unit.
Q＝k 1 q+k 2 q+k 3 q+...+k i q
i＝2，3，4，...k i ＝0，1 (7)
For the series flow combined plunger unit combination including but not limited to fibonacci series, arithmetic series and geometric series, the total flow of the digital pump is shown in the following formula (8), wherein a control signal of a digital flow distribution valve corresponding to an ith plunger unit is a control signal of the digital flow distribution valve, and the ith digital flow distribution valve control signal is a pulse amplitude modulation signal of non-binary coding, so that high resolution and continuity adjustment of the flow of the digital pump are realized;
Q＝k 1 q 1 +k 2 q 2 +k 3 q 3 +...+k i q i +k i+1 q i+1
i＝2，3，4，...k i ＝0，1 k i+1 ∈[0，1] (8)
the implementation of the present invention is specifically described below, the multiple cam curve is set to be a 6-multiple cam curve, and the multiple cam digital pump system shown in fig. 2 to 6 includes a 6-multiple cam curve and 1 plunger unit, but is not limited to being adapted to be only a 6-multiple cam curve and 1 plunger unit, and may also include any other number of multiple cam 7 curves and plunger units;
the displacement, speed and acceleration equations of the profile curve of the cam 7 respectively enable the lift-return cycle k=6 of the formula (3), the formula (4) and the formula (5), and the theoretical flow rate of the stable operation of the ith plunger unit enables the plunger unit oil suction-discharge cycle n= 6,i =36 of the formula (6).
In order to avoid the inherent contradiction relation between the high response speed and the large flow capacity of the flow distribution valve, the embodiment does not adopt PWM control or plunger stroke control strategy, and the series flow combined plunger unit combination comprises but is not limited to a fibonacci array, an arithmetic array and an arithmetic array, only one digital flow distribution valve control signal is a pulse amplitude modulation signal of non-binary coding, so that the high resolution and continuous adjustment of the flow of the digital pump are realized. Designating a displacement control rule as shown in table 1 according to an input flow pulsation rate minimum criterion;
the 1-frequency multiplication annular inner cam is matched with digital pumps with different numbers, namely six plunger pumps are respectively positioned in 1, 2, 3 and 6 digital pumps, so that theoretical superposition displacement of the 4 annular inner cams during stable operation of the radial digital pumps is respectively obtained, and the theoretical superposition displacement is shown in figure 7. From the above, it can be seen that if the trigonometric function motion law is adopted as the plunger motion law, the six-plunger pump with the annular inner cam theoretically has different fluctuation degrees of flow, and the follow-up control and regulation system needs to consider the variable factors of the wind speed, the plunger unit arrangement position and the cam lift-return curve matching;
in addition, 1 digital pump is set to be composed of 6 plunger pumps and corresponding electromagnetic switch valves. As shown in fig. 7, even in the case of the same number of plunger pumps, as the number of digital pumps increases, that is, the displacement coefficient decreases, the flow pulsation at the input end of the hydraulic system gradually decreases, as shown by the 6 digital pumps (36 plungers in total) with asterisks in fig. 7, which is a 1/6 displacement coefficient. And from the standpoint of control resolution, an increase in the number of digital pumps is advantageous for achieving a smaller displacement factor, as shown in fig. 8.
Therefore, from the perspective of superposition of flow pulsation and minimum resolution of displacement coefficient, the invention selects cam profile curves with frequency multiplied by 6, and cooperates with 36 plunger pumps (namely 6 digital pumps) to jointly form an input element of the hydraulic end of the wind power energy transmission system.
Binary coding control rule of table 1 6 frequency multiplication 36 congruent plunger digital pump
Figure BDA0003638767020000081
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Figure BDA0003638767020000091
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Claims (4)

1. A multiple frequency cam digital pump comprising a cam (7), characterized in that: a plurality of plunger units are uniformly distributed on the circumference of the cam (7), the cam (7) drives the plunger units to complete the oil suction-discharge process, each plunger unit is provided with a digital flow distribution valve (1), and each digital flow distribution valve (1) is controlled to be communicated with a high-pressure oil way or a low-pressure oil way through binary coding;
the cam (7) is provided with a multiple frequency cam curve profile;
the multiple frequency cam curve profile is provided with a plurality of lift-return cycles;
the plunger unit comprises a plunger seat (5), and a plunger rod (4) is connected in a sliding manner in the plunger seat (5);
the digital flow distribution valve (1) comprises a high-speed electromagnetic valve, a one-way valve, an oil inlet passage port and an oil discharge passage port, wherein the oil inlet passage port is communicated with the plunger seat (5), the oil discharge passage port is provided with two outlet ends, one outlet end of the oil discharge passage port is connected with a high-pressure oil path, the other outlet end of the oil discharge passage port is communicated with a low-pressure oil path, the one-way valve is arranged in the outlet end connected with the high-pressure oil path, and the high-speed electromagnetic valve is arranged in the outlet end connected with the low-pressure oil path;
the binary codes are signals '0' and '1', when the plunger rod (4) is in a return state, the signal '0' controls the high-speed electromagnetic valve to be opened, hydraulic medium discharged by the plunger seat (5) is discharged into a low-pressure oil way through the high-speed electromagnetic valve, the signal '1' controls the high-speed electromagnetic valve to be closed, and the hydraulic medium discharged by the plunger seat (5) is discharged into the high-pressure oil way through the one-way valve;
the plunger rod (4) is rotationally connected with a first roller (2) and a second roller (3);
the multiple frequency cam curve profile comprises an inner multiple frequency cam curve profile and an outer multiple frequency cam curve profile, the inner multiple frequency cam curve profile is identical to the outer multiple frequency cam curve profile in curve, the first roller (2) is contacted with the outer multiple frequency cam curve profile, and the second roller (3) is contacted with the inner multiple frequency cam curve profile.
2. The multiple frequency cam digital pump of claim 1, wherein: the multiple frequency cam curve is a trigonometric function type curve, an interpolation curve or a fitting curve.
3. A multiple frequency cam digital pump according to any of claims 1 to 2, characterized in that: the binary code control part plunger unit is connected with the high-pressure oil circuit.
4. A multiple frequency cam digital pump according to any of claims 1 to 2, characterized in that: the plurality of plunger units are fixedly connected to the tower (6), and the cam (7) is fixedly connected with the wind wheel and rotates together.
CN202210513634.1A 2022-05-11 2022-05-11 Multiple frequency cam digital pump Active CN114962200B (en)

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Application Number Priority Date Filing Date Title
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CN114962200A CN114962200A (en) 2022-08-30
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