Controllable pressure ratio liquid drive supercharging system and control method

Abstract

This invention discloses a controllable pressure ratio hydraulically driven booster system and control method, comprising: two or more booster units, each booster unit connected in series according to its stage number; the driving device for each booster unit is an independent variable flow hydraulic pump station; each booster unit's inlet and outlet pipes are equipped with pressure gauges and temperature detectors; and a control system that receives data from the pressure gauges and temperature detectors and controls the flow rate of the corresponding independent variable flow hydraulic pump station. This invention enables real-time adjustment of the pressure ratio of a multi-stage compressor, ensuring that the compressor always approaches a constant pressure ratio, significantly reducing compressor energy consumption.

Description

Technical Field

[0001] This invention relates to the field of compressors. More specifically, this invention relates to a controllable pressure ratio liquid-driven booster system and its control method. Background Technology

[0002] According to compressor design theory, compressor efficiency is directly related to pressure ratio. When using multi-stage compression, constant pressure ratio compression consumes the least energy. Therefore, pressure ratio regulation technology is of great significance for reducing the total energy consumption of compressors. Most existing compressors use a single drive system, and the compressor pressure ratio is basically determined at the initial design stage and is difficult to adjust. This is not energy-efficient for compressors used in hydrogen (gas) refueling stations that operate under varying conditions.

[0003] Therefore, it is necessary to innovate and develop new compressor pressure ratio regulation technology to dynamically adjust the compressor pressure ratio according to the real-time operating conditions of the compressor, thereby improving the compressor efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a controllable pressure ratio liquid-driven booster system and control method to achieve real-time adjustment of the pressure ratio of a multi-stage compressor, so that the compressor is always close to the constant pressure ratio state, and significantly reduce the energy consumption of the compressor.

[0005] The technical solution adopted by this invention to solve this technical problem is: a controllable pressure ratio hydraulic booster system, comprising:

[0006] Two or more stages of booster units, with each stage connected in series according to the number of stages; the driving device for each stage of booster units is an independent variable flow hydraulic pump station;

[0007] Each stage of the booster unit is equipped with a pressure gauge and a temperature detector in its intake and exhaust pipes.

[0008] The control system receives data from pressure gauges and temperature detectors, and controls the flow rate of the corresponding independent variable flow hydraulic pump station.

[0009] Preferably, the booster unit includes: a compression cylinder and a piston disposed in the compression cylinder, the compression cylinder being divided into a pneumatic cylinder and a hydraulic cylinder by the piston, the pneumatic cylinder being provided with an inlet pipe and an outlet pipe, the inlet pipe and the outlet pipe being provided with control valves, the hydraulic cylinder being provided with a hydraulic oil pipe, and the hydraulic oil pipe being connected to the independent variable flow hydraulic pump station.

[0010] Preferably, a cooler is provided on the air intake pipe.

[0011] Preferably, the booster unit has a three-stage structure, including: a first-stage booster unit, a second-stage booster unit, and a third-stage booster unit;

[0012] A primary booster unit and a secondary booster unit are connected in series, and a secondary booster unit and a tertiary booster unit are connected in series. The outlet pipe of the secondary booster unit is equipped with a cooler, and the outlet pipe of the secondary booster unit is connected to the first storage tank group through the cooler. The first storage tank group is connected to the first hydrogen dispenser. The first storage tank group is connected to the tertiary booster unit through an inlet pipe. The outlet pipe of the tertiary booster unit is equipped with a cooler, and the outlet pipe of the tertiary booster unit is connected to the second storage tank group / second hydrogen dispenser through the cooler. The second storage tank group is connected to the second hydrogen dispenser.

[0013] The present invention utilizes a control method for the controllable pressure ratio hydraulic booster system, comprising the following steps:

[0014] S1. The control system monitors the pressure in the compressor's inlet and outlet pipes, and distributes the pressure ratio of each stage of the compressor according to the principle of equal pressure ratio.

[0015]

[0016] In the formula, ε i Let i be the pressure ratio of the i-th stage. Let i be the exhaust pressure of the i-th stage. Q is the intake pressure for the i-th stage; i Let i be the flow rate of the hydraulic pump of the i-th stage compressor. Let be the piston area of ​​the i-th stage compression chamber. Let be the hydraulic piston area of ​​the i-th stage compressor;

[0017] S2. Establish the relationship between flow rate and physical quantities such as hydraulic pump speed and deflection angle:

[0018] Q i =f(γ) i N i )

[0019] In the formula, N i Let γ be the rotational speed of the i-th stage hydraulic pump. i For the flow control quantity of the i-th stage hydraulic pump (such as the swashplate angle, etc.);

[0020] S3. Substitute S2 into S1 to determine the relationship between the flow functions of the two preceding and following hydraulic pumps:

[0021]

[0022] S4. Determine the flow rate Q1 of the first-stage compressor hydraulic pump based on the compressor's flow requirements;

[0023] Q1 = f(γ1, N1)

[0024] S5. Calculate the flow rate of the corresponding independent variable flow hydraulic pump station for each subsequent stage of compressor booster unit based on S3, and design the electrical control program according to S2, so that the actual flow rate of each stage of hydraulic pump is in accordance with the calculated Q. i The output achieves the purpose of isobaric compression at each stage of the compressor.

[0025] The present invention has at least the following beneficial effects:

[0026] 1) The present invention can realize real-time adjustment of the pressure ratio of multi-stage compressors so that the compressor is always close to the state of constant pressure ratio, which significantly reduces the energy consumption of the compressor;

[0027] 2) The compressor's discharge volume can be quickly adjusted through the variable flow control of the hydraulic station.

[0028] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of one embodiment of the controllable pressure ratio hydraulic booster system of the present invention.

[0030] Explanation of reference numerals in the attached diagram: 1. Primary booster unit; 2. Secondary booster unit; 3. Tertiary booster unit; 4. Independent variable flow hydraulic pump station; 5. Cylinder; 6. Oil cylinder; 7. Piston. Detailed Implementation

[0031] The present invention will now be described in detail and completely with reference to the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention with reference to the accompanying drawings, it should be particularly noted that the technical solutions and features provided in various parts of the present invention, including the following description, can be combined with each other without conflict.

[0032] Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific implementation process is as follows:

[0034] This invention provides a controllable pressure ratio hydraulic booster system, comprising:

[0035] Two or more stages of booster units are connected in series according to their stage number. For example, the first-stage booster unit is connected in series with the second-stage booster unit, the second-stage booster unit is connected in series with the third-stage booster unit, and so on, with the i-1-stage booster unit connected in series with the i-stage booster unit. When the booster units are connected in series, the connecting pipelines can be directly connected, or a tank group can be set between the connecting pipelines. The driving device for each stage of the booster unit is an independent variable flow hydraulic pump station.

[0036] Each stage of the booster unit is equipped with a pressure gauge and a temperature detector in its intake and exhaust pipes.

[0037] The control system receives data from pressure gauges and temperature detectors, and controls the flow rate of the corresponding independent variable flow hydraulic pump station.

[0038] In the above technical solution, by measuring the inlet and outlet pressures of the compressor in real time, the motion frequency ratio of the booster unit when the isobaric compression is achieved is calculated, and then the flow rate of the independent variable flow hydraulic pump station corresponding to each booster cylinder is dynamically adjusted to achieve dynamic control of the pressure ratio of the multi-stage compressor, achieve the isobaric compression state, and improve the efficiency of the compressor.

[0039] This technical solution may also include the following technical details to better achieve the technical effect: The pressurization unit includes: a compression cylinder and a piston 7 disposed in the compression cylinder. The compression cylinder is divided into a pneumatic cylinder 5 and an oil cylinder 6 by the piston. The pneumatic cylinder 5 is provided with an air inlet pipe and an air outlet pipe. The air inlet pipe and the air outlet pipe are provided with control valves. The oil cylinder 6 is provided with a hydraulic oil pipe, and the hydraulic oil pipe is connected to the independent variable flow hydraulic pump station.

[0040] This technical solution may also include the following technical details to better achieve the technical effect: a cooler is installed on the air intake pipe.

[0041] In a preferred embodiment of the controllable pressure ratio hydraulic booster system of this application, such as Figure 1 As shown, the booster unit has a three-stage structure, including: a first-stage booster unit 1, a second-stage booster unit 2, and a third-stage booster unit 3;

[0042] A primary booster unit 1 and a secondary booster unit 2 are connected in series, and a secondary booster unit 2 and a tertiary booster unit 3 are connected in series. The outlet pipe of the secondary booster unit is equipped with a cooler, and the outlet pipe of the secondary booster unit through the cooler is connected to the first storage tank group, which is a 45MPa storage tank group. The first storage tank group is connected to the first hydrogen dispenser, which is a 35MPa hydrogen dispenser. The first storage tank group is connected to the tertiary booster unit through an inlet pipe. The outlet pipe of the tertiary booster unit is equipped with a cooler, and the outlet pipe of the tertiary booster unit through the cooler is connected to the second storage tank group / second hydrogen dispenser. The second storage tank group is a 90MPa storage tank group, and the second storage tank group is connected to the second hydrogen dispenser.

[0043] In another embodiment, using the control method of a controllable pressure ratio liquid-driven booster system, S1, the control system monitors the compressor's inlet and outlet pipe pressures and distributes the compressor's pressure ratios at each stage according to the principle of equal pressure ratio, i.e.

[0044]

[0045] In the formula, ε i Let i be the pressure ratio of the i-th stage. Let i be the exhaust pressure of the i-th stage. Q is the intake pressure for the i-th stage; i Let i be the flow rate of the hydraulic pump of the i-th stage compressor. Let be the piston area of ​​the i-th stage compression chamber. Let be the hydraulic piston area of ​​the i-th stage compressor;

[0046] S2. Establish the relationship between flow rate and physical quantities such as hydraulic pump speed and deflection angle:

[0047] Q i =f(γ1, N1)

[0048] In the formula, N i Let γ be the rotational speed of the i-th stage hydraulic pump. i For the flow control quantity of the i-th stage hydraulic pump (such as the swashplate angle, etc.);

[0049] S3. Substitute S2 into S1 to determine the relationship between the flow functions of the two preceding and following hydraulic pumps:

[0050]

[0051] S4. Determine the flow rate Q1 of the first-stage compressor hydraulic pump based on the compressor's flow requirements;

[0052] Q1 = f(γ1, N1)

[0053] S5. Calculate the flow rate of the corresponding independent variable flow hydraulic pump station for each subsequent stage of compressor booster unit based on S3, and design the electrical control program according to S2, so that the actual flow rate of each stage of hydraulic pump is in accordance with the calculated Q. i输出 This achieves the goal of isobaric compression at each stage of the compressor.

[0054] Derivation of the control method for a controllable pressure ratio hydraulic booster system:

[0055] Table 1

[0056] Symbol Explanation Table

[0057]

[0058] According to the definition of compressor pressure ratio:

[0059]

[0060] According to the compressor principle, the compressor's working process is a variable process, which can be represented as:

[0061] pv k =const. (2)

[0062] That is:

[0063]

[0064] When the compression process is isothermal, then:

[0065]

[0066] According to compressor design theory, the compressor consumes the least energy when the compression process is isobaric compression. Therefore, to achieve the minimum energy consumption, the following must be achieved:

[0067]

[0068] In other words, the requirements are:

[0069]

[0070] Therefore, the core of the controllable pressure ratio liquid-driven booster system is to achieve the purpose of energy-saving control by independently and intelligently controlling each stage of the compressor so that the volume before and after compression reaches the volume ratio required for the isobaric ratio.

[0071] For compressors that have already been designed, then:

[0072]

[0073] Since the area of ​​the booster cylinder piston is fixed for a specific compressor, that is, Ai Since it is known, we can conclude that:

[0074]

[0075] Therefore, the main feature of the controllable pressure ratio hydraulic booster system described in this patent is that by controlling the flow rate of the hydraulic system, the movement of the hydraulic piston is controlled so that the displacement of the piston rod satisfies the relationship (8).

[0076] For hydraulic cylinder control systems, we have:

[0077]

[0078] Based on the above analysis, this patent will control the flow rate of the hydraulic variable pump so that the flow rate of the hydraulic variable pump satisfies the relationship (9), thereby achieving the pressure ratio control of the compressor and achieving the goal of energy-saving operation of the compressor.

[0079] For hydraulic variable displacement pumps, their flow rate typically has a definite functional relationship with a certain physical quantity (such as swing angle, eccentricity, motor speed, etc.). Therefore, the flow rate of the hydraulic pump can be controlled by controlling these physical quantities. That is:

[0080] Q i =f(γ) i N i (10)

[0081] Substituting equation (10) into equation (9), we get:

[0082]

[0083] Obviously, after determining the flow rate of the first stage of the compressor, the flow rates of the subsequent second to nth stages are controlled according to equation (11). By controlling the flow rate of each stage of the compressor's hydraulic pump, the pressure ratio of each stage of the compressor can be indirectly controlled, thereby minimizing the energy consumption of the hydraulically driven compressor. This realizes the controllable pressure ratio hydraulically driven booster system described in this patent, achieving the goal of energy saving and emission reduction.

[0084] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A control method for a controllable pressure ratio hydraulic booster system, characterized in that, The hydraulic booster system includes: Two or more stages of booster units, with each stage connected in series according to the stage number; the driving device for each stage of booster units is an independent variable flow hydraulic pump station; Each stage of the booster unit is equipped with a pressure gauge and a temperature detector in its intake and exhaust pipes. The control system receives data from pressure gauges and temperature detectors and controls the flow rate of the corresponding independent variable flow hydraulic pump station. The booster unit includes: a compression cylinder and a piston disposed in the compression cylinder. The compression cylinder is divided into a pneumatic cylinder and a hydraulic cylinder by the piston. The pneumatic cylinder is provided with an air inlet pipe and an air outlet pipe. Control valves are provided on the air inlet pipe and the air outlet pipe. The hydraulic cylinder is provided with a hydraulic oil pipe, and the hydraulic oil pipe is connected to the independent variable flow hydraulic pump station. The control method includes the following steps: S1. The control system monitors the pressure in the compressor's inlet and outlet pipes, and distributes the pressure ratio of each stage of the compressor according to the principle of equal pressure ratio. In the formula, Let i be the pressure ratio of the i-th stage. Let i be the exhaust pressure of the i-th stage. Let be the intake pressure of the i-th stage; Let i be the flow rate of the hydraulic pump of the i-th stage compressor. Let be the piston area of ​​the i-th stage compression chamber. Let be the hydraulic piston area of ​​the i-th stage compressor; The exhaust pressure of the nth stage. is the intake pressure of the first stage, and n is the number of compression stages of the compressor; S2. Establish the relationship between flow rate and the physical quantities of hydraulic pump speed and deflection angle: In the formula, Let be the rotational speed of the i-th stage hydraulic pump. For the flow control quantity of the i-th stage hydraulic pump; S3. Substitute S2 into S1 to determine the relationship between the flow functions of the two preceding and following hydraulic pumps: S4. Determine the flow rate of the first-stage compressor hydraulic pump based on the compressor's flow requirements. ; S5. Based on S3, calculate the flow rate of the corresponding independent variable flow hydraulic pump station for each subsequent stage of compressor booster unit, and design the electrical control program according to S2, so that the actual flow rate of each stage of hydraulic pump is as calculated. The output achieves the purpose of isobaric compression at each stage of the compressor.

2. The control method as described in claim 1, characterized in that, A cooler is installed on the air intake pipe.

3. The control method as described in any one of claims 1 to 2, characterized in that, The booster unit has a three-stage structure, including: a primary booster unit, a secondary booster unit, and a tertiary booster unit; A primary booster unit and a secondary booster unit are connected in series, and a secondary booster unit and a tertiary booster unit are connected in series. The outlet pipe of the secondary booster unit is equipped with a cooler, and the outlet pipe of the secondary booster unit is connected to the first storage tank group through the cooler. The first storage tank group is connected to the first hydrogen dispenser. The first storage tank group is connected to the tertiary booster unit through an inlet pipe. The outlet pipe of the tertiary booster unit is equipped with a cooler, and the outlet pipe of the tertiary booster unit is connected to the second storage tank group and the second hydrogen dispenser through the cooler. The second storage tank group is connected to the second hydrogen dispenser.

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