Hydraulic power output system

Abstract

The invention discloses a hydraulic power output system, and relates to the technical field of ocean energy utilization, the hydraulic power output system comprises a floater, a hydraulic cylinder, a main oil way, an oil tank and a power generation assembly, the floater is used for floating on the sea surface, and the floater is connected with a piston rod of the hydraulic cylinder; an upper oil cavity and a lower oil cavity of the hydraulic cylinder are both connected with an oil inlet of the main oil way and the oil tank, and an oil outlet of the main oil way is connected with the power generation assembly. The multiple sets of power generation assemblies are arranged, and the multiple sets of power generation assemblies are used for generating power under different wave conditions. A high-pressure energy accumulator is further arranged on the main oil way and connected with a proportional valve in series. According to the invention, the loop stability of the hydraulic PTO system can be ensured, and the power generation function under various wave conditions can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of ocean energy utilization, and in particular to a hydraulic power output system. Background Art

[0002] As a type of ocean energy, wave energy has the characteristics of large reserves and high energy flow density, and has huge development potential.

[0003] Wave energy devices convert energy into electricity through a power take-off (PTO) system, which is their core function. Depending on the operating principle of a wave energy device, the PTO system can be pneumatic, hydraulic, or direct-drive. Hydraulic transmission technology, with its low-frequency, high-torque, high-power transmission, fast frequency response, and hydraulic overload protection, is well-suited to the low-frequency, high-power characteristics of waves, and therefore many devices utilize hydraulic PTO systems. Currently, hydraulic cylinders in hydraulic PTO systems do not output hydraulic oil during reciprocating motion, resulting in flow pulsation. This non-constant flow is affected by pipe resistance and friction in the hydraulic circuit, affecting system pressure stability and generating vibration and noise in system components. To improve device performance and lifespan, accumulators are often added to the circuit to eliminate pressure pulsation. Therefore, optimizing the accumulator's ability to absorb unstable system pressure is of practical value in optimizing system design. Furthermore, wave conditions vary significantly from season to season, resulting in significant variations in the wave power absorbed by the buoy array. Current hydraulic system designs often use a single generator, which is unable to achieve power generation under all wave conditions.

[0004] Therefore, a hydraulic power output system is provided to solve the above problems existing in the prior art. Summary of the Invention

[0005] The purpose of the present invention is to provide a hydraulic power output system to solve the problems existing in the prior art, to ensure the circuit stability of the hydraulic PTO system, and to realize the power generation function of various wave conditions.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a hydraulic power output system, including a float, a hydraulic cylinder, a main oil circuit, an oil tank and a power generation component. The float is used to float on the sea surface, and the float is connected to the piston rod of the hydraulic cylinder. The upper oil chamber and the lower oil chamber of the hydraulic cylinder are both connected to the oil inlet of the main oil circuit and the oil tank, and the oil outlet of the main oil circuit is connected to the power generation component; the power generation component is provided in multiple groups, and the multiple groups of the power generation components are used to generate electricity under different wave conditions; a high-pressure accumulator is also provided on the main oil circuit, and the high-pressure accumulator is connected in series with a proportional valve.

[0008] Preferably, any group of the power generation components includes a working oil circuit, a solenoid valve, a hydraulic motor and a generator. The oil inlet of the working oil circuit is connected to the oil outlet of the main oil circuit, and the oil outlet of the working oil circuit is connected to the oil tank. The solenoid valve and the hydraulic motor are arranged in sequence on the working oil circuit, and the hydraulic motor is used to drive the generator to generate electricity.

[0009] Preferably, the working pressure of the high-pressure accumulator is 25-35 MPa, and a pressure sensor is also provided on the main oil circuit.

[0010] Preferably, a plurality of the hydraulic cylinders are provided, the plurality of hydraulic cylinders are distributed in an array, and the piston rod of any one of the hydraulic cylinders is connected to one of the floats.

[0011] Preferably, the upper oil chamber and the lower oil chamber of the hydraulic cylinder are connected to the main oil circuit and the oil tank through a one-way valve group.

[0012] Preferably, the power generation component is provided with two groups, including a first power generation component and a second power generation component, wherein the first power generation component includes a first working oil circuit, a first solenoid valve, a first hydraulic motor and a first generator, the oil inlet of the first working oil circuit is connected to the oil outlet of the main oil circuit, the oil outlet of the first working oil circuit is connected to the oil tank, the first solenoid valve and the first hydraulic motor are arranged in sequence on the first working oil circuit, and the first hydraulic motor is used to drive the first generator to generate electricity; the second power generation component includes a second working oil circuit, a second solenoid valve, a second hydraulic motor and a second generator, the oil inlet of the second working oil circuit is connected to the oil outlet of the main oil circuit, the oil outlet of the second working oil circuit is connected to the oil tank, the second solenoid valve and the second hydraulic motor are arranged in sequence on the second working oil circuit, and the second hydraulic motor is used to drive the second generator to generate electricity.

[0013] Preferably, when the circuit flow rate is greater than 400 L / min, the first solenoid valve is opened and the displacement of the first hydraulic motor is 800 cm 3 / rev, the rotation speed is 1200rpm, and the rated load of the first generator is 200kW;

[0014] When the circuit flow rate is less than 400L / min, the second solenoid valve is opened and the displacement of the second hydraulic motor is 250cm 3 / rev, the rotation speed is 1600rpm, and the rated load of the second generator is 50kW.

[0015] Preferably, the generator is a three-phase permanent magnet synchronous generator.

[0016] Preferably, a speed regulating valve is also provided on the working oil circuit.

[0017] Preferably, an overflow valve is also provided on the main oil circuit.

[0018] Compared with the prior art, the present invention has achieved the following technical effects:

[0019] The present invention is provided with multiple groups of power generation components for generating electricity under different wave conditions, realizing the function of generating electricity under various wave conditions and avoiding the phenomenon of failure to start the power generation load or overload and burning of the generator; moreover, the main oil circuit of the present invention is also provided with a high-pressure accumulator, and the high-pressure accumulator is connected in series with a proportional valve. By controlling the opening size of the proportional valve in real time, the diameter of the oil inlet pipeline of the high-pressure accumulator is changed to improve the working performance of the accumulator. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a schematic diagram of the adaptive accumulator circuit in an embodiment of the present invention;

[0022] Figure 2 Schematic diagram of the structure of the hydraulic power output system in an embodiment of the present invention.

[0023] In the figure: 1-oil tank; 2-main oil circuit; 3-proportional valve; 4-pressure sensor; 5-overflow valve; 6-high-pressure accumulator; 301-first float; 302-second float; 401-first hydraulic cylinder; 402-second hydraulic cylinder; 501-first one-way valve group; 502-second one-way valve group; 601-first solenoid valve; 602-second solenoid valve; 701-first speed control valve; 702-second speed control valve; 801-first generator; 802-second generator; 901-first hydraulic motor; 902-second hydraulic motor. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] The purpose of the present invention is to provide a hydraulic power output system to solve the problems existing in the prior art, to ensure the circuit stability of the hydraulic PTO system, and to realize the power generation function of various wave conditions.

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] like Figure 1-Figure 2 As shown, a hydraulic power output system is provided in this embodiment, which mainly includes a float, a hydraulic cylinder, a main oil circuit 2 and a power generation component. The float is preferably a cylindrical float, which is used to float on the sea surface and is partially submerged in the sea level. The bottom of the float is connected to the piston rod of the hydraulic cylinder. The hydraulic cylinder is vertically arranged. The movement of ocean waves drives the float, causing the float to move vertically to push the piston rod of the hydraulic cylinder relative to the cylinder body, so that the oil is sucked or compressed in the hydraulic cylinder to generate high-pressure oil; wherein, the upper oil chamber and the lower oil chamber of the hydraulic cylinder are both connected to the oil inlet of the main oil circuit 2, the oil outlet of the main oil circuit 2 is connected to the power generation component, and the upper oil chamber and the lower oil chamber of the hydraulic cylinder are also connected to the oil tank 1.

[0029] In this embodiment, there are multiple groups of power generation components, and any group of power generation components includes a working oil circuit, a solenoid valve, a hydraulic motor and a generator. The oil inlet of the working oil circuit is connected to the oil outlet of the main oil circuit 2, and the oil outlet of the working oil circuit is connected to the oil tank 1. The solenoid valve and the hydraulic motor are arranged in sequence on the working oil circuit, and the hydraulic motor is used to drive the generator to generate electricity. Among them, multiple groups of power generation components are used to generate electricity under different wave conditions.

[0030] Furthermore, a high-pressure accumulator 6 is provided on the main oil circuit 2 , and the high-pressure accumulator 6 is connected in series with the proportional valve 3 .

[0031] In this embodiment, multiple groups of power generation components are provided for generating electricity under different wave conditions, realizing the function of generating electricity under various wave conditions and avoiding the phenomenon of failure to start the power generation load or overload and burning the generator; moreover, in this embodiment, a high-pressure accumulator 6 is also provided on the main oil circuit 2, and the high-pressure accumulator 6 is connected in series with the proportional valve 3. By controlling the real-time change of the opening size of the proportional valve 3, the diameter of the oil inlet pipeline of the high-pressure accumulator 6 is changed to improve the working performance of the accumulator.

[0032] In this embodiment, the high-pressure accumulator 6, coupled in series with the proportional valve 3, produces significantly smaller pressure fluctuations in the hydraulic system than in circuits containing conventional accumulators. This demonstrates that the presence of a proportional flow valve controlling the high-pressure accumulator 6 significantly improves the stability of the main circuit pressure. Furthermore, as the wave period increases, the pressure fluctuation range in the hydraulic PTO system incorporating a conventional accumulator increases significantly, while the pressure fluctuation range in the hydraulic PTO system incorporating the proportional valve 3 remains essentially unchanged, demonstrating that the proportional valve 3-controlled accumulator exhibits greater adaptability and stability.

[0033] In this embodiment, a pressure sensor 4 is further provided on the main oil circuit 2 .

[0034] In this embodiment, it is necessary to further explain that the accumulator can be divided into low-pressure, medium-pressure and high-pressure accumulators 6 according to different working pressures. Generally, an accumulator with a pressure ≥ 25MPa (250bar) can be called a high-pressure accumulator 6. In this embodiment, the high-pressure accumulator 6 usually operates in the range of 25-35MPa (250-350bar) to meet the requirements of high power density and fast response. The diameter of the oil inlet pipe of the high-pressure accumulator 6 of this embodiment can be adjusted in real time by the proportional valve 3. When the loop flow is small, the minimum diameter of the oil inlet pipe of the high-pressure accumulator 6 can be adjusted to 12mm. When the loop flow is large, the maximum diameter of the oil inlet pipe of the high-pressure accumulator 6 can be adjusted to 50mm.

[0035] The working principle of the high-pressure accumulator 6 in this embodiment is as follows: Figure 1 As shown, the natural frequency ω of the high-pressure accumulator 6 A Denoted as:

[0036]

[0037] Where: A is the flow area of the pipeline in front of the high-pressure accumulator 6; P0 is the steady-state pressure of the system; K is the gas adiabatic index; l is the length of the pipeline in front of the high-pressure accumulator 6; ρ is the oil density; V0 is the steady-state value of the gas volume in the high-pressure accumulator 6.

[0038] When the system steady-state pressure changes, it can be known that the natural frequency ω of the high-pressure accumulator 6 A will change; or due to the unstable operation of the hydraulic pump, the flow pulsation angular frequency ω Q This will cause ω A ≠ω Q , which makes the high-pressure accumulator 6 have an unsatisfactory effect in absorbing pressure pulsations. In order to achieve a good effect of the high-pressure accumulator 6 absorbing pressure pulsations during the entire working process of the system, the high-pressure accumulator 6 must be adaptive, that is, its natural frequency ω A and flow pulsation angular frequency ω Q Therefore, the design is as follows Figure 1 Adaptive accumulator circuit shown. Figure 1 In the example, the pressure sensor 4 is used to measure the system pressure. Based on the measured pressure, the steady-state pressure P0 of the system and the pressure pulsation angular frequency ω caused by flow pulsation can be calculated. Q To make ω A =ω Q ,due

[0039]

[0040] At this time, the corresponding electrical signal is applied to the proportional valve 3, so that the valve port area of the proportional valve 3 is equal to the flow area A calculated by the above formula. In this way, during the operation of the system, no matter what reason causes ω A ≠ω Q , the adaptive accumulator can adjust the flow area A in time, so that A =ω Q .

[0041] In this embodiment, a plurality of hydraulic cylinders are provided, and the plurality of hydraulic cylinders are distributed in an array, and a piston rod of any of the hydraulic cylinders is connected to a float.

[0042] In a preferred embodiment, two hydraulic cylinders are provided, including a first hydraulic cylinder 401 and a second hydraulic cylinder 402. The piston rod of the first hydraulic cylinder 401 is connected to the first float 301, and the piston rod of the second hydraulic cylinder 402 is connected to the second float 302. The number of floats and hydraulic cylinders can be selected based on needs and is not limited to two groups. Three, four, or even more groups can also be provided, depending on the system's design objectives, resource requirements, and application scenarios. Increasing the number of floats and hydraulic cylinders can improve the system's power generation capacity and stability.

[0043] In this embodiment, multiple groups of floats and hydraulic cylinders are arranged in an array, which has the following advantages:

[0044] 1. Improve power generation efficiency: More floats and hydraulic cylinders can capture more wave energy and increase total power generation;

[0045] 2. Enhance system stability: Multiple groups of floats and hydraulic cylinders can balance the fluctuations of wave forces, reduce the impact of single point failures, and improve the overall reliability of the system;

[0046] 3. Strong adaptability: The array design can be flexibly adjusted according to the wave conditions in different sea areas to optimize energy capture efficiency;

[0047] 4. Reduce unit power generation costs: Large-scale deployment can share construction and maintenance costs, reduce unit power generation costs, and improve economic efficiency;

[0048] 5. Environmentally friendly: The array wave energy device power generation system has little impact on the marine ecology and does not produce greenhouse gases, which meets the requirements of sustainable development;

[0049] 6. Modular design: Array wave energy device power generation systems usually adopt modular design, which is convenient for expansion and maintenance. The failure of a single module will not affect the overall operation.

[0050] In this embodiment, the upper oil chamber and the lower oil chamber of the hydraulic cylinder are connected to the main oil circuit 2 and the oil tank 1 through a one-way valve group. The one-way valve group is provided to play a rectifying role. The oil tank 1 is equivalent to a low-pressure accumulator, supplying oil to the hydraulic cylinder; wherein, the upper oil chamber and the lower oil chamber of the first hydraulic cylinder 401 are connected to the main oil circuit 2 and the oil tank 1 through a first one-way valve group 501, and the upper oil chamber and the lower oil chamber of the second hydraulic cylinder 402 are connected to the main oil circuit 2 and the oil tank 1 through a second one-way valve group 502.

[0051] In this embodiment, the power generation component is provided with two groups, including a first power generation component and a second power generation component, wherein the first power generation component includes a first working oil circuit, a first solenoid valve 601, a first hydraulic motor 901 and a first generator 801, the oil inlet of the first working oil circuit is connected to the oil outlet of the main oil circuit 2, the oil outlet of the first working oil circuit is connected to the oil tank 1, the first solenoid valve 601 and the first hydraulic motor 901 are sequentially arranged on the first working oil circuit, and the first hydraulic motor 901 is used to drive the first generator 801 to generate electricity; the second power generation component includes a second working oil circuit, a second solenoid valve 602, a second hydraulic motor 902 and a second generator 802, the oil inlet of the second working oil circuit is connected to the oil outlet of the main oil circuit 2, the oil outlet of the second working oil circuit is connected to the oil tank 1, the second solenoid valve 602 and the second hydraulic motor 902 are sequentially arranged on the second working oil circuit, and the second hydraulic motor 902 is used to drive the second generator 802 to generate electricity.

[0052] In this embodiment, the first generator 801 and the second generator 802 can be selected according to specific working requirements, and are preferably three-phase permanent magnet synchronous generators.

[0053] When the loop flow rate is less than 400 L / min, the second solenoid valve 602 is opened and the displacement is selected to be 250 cm 3 / rev, the second hydraulic motor 902 with a rotation speed of 1600rpm, the corresponding second generator 802 with a rated load of 50kW; when the circuit flow is greater than 400L / min, the first solenoid valve 601 is opened, and the displacement is selected to be 800cm 3The first hydraulic motor 901 has a rotation speed of 1200 rpm and a corresponding rated load of the first generator 801 is 200 kW.

[0054] In this embodiment, it should be noted that the power generation components are not limited to two groups, and three, four or more groups can be provided to achieve multi-level opening.

[0055] In this embodiment, a speed regulating valve is further provided on the working oil circuit, wherein a first speed regulating valve 701 is provided on the first working oil circuit, a second speed regulating valve 702 is provided on the second working oil circuit, and a relief valve 5 is further provided on the main oil circuit 2. By providing the speed regulating valve and the relief valve 5 to adjust the working flow, the output power regulation is realized, and then throttling and excess flow overflow are realized when the flow of the main oil circuit 2 is too large, thereby protecting the PTO system.

[0056] The working principle of the hydraulic power output system in this embodiment is as follows:

[0057] The movement of ocean waves drives the first float 301, causing it to move vertically, pushing the piston rod of the first hydraulic cylinder 401 relative to the cylinder body. This causes the suction or compression chamber in the first hydraulic cylinder 401 to generate high-pressure oil. When the piston rod of the first hydraulic cylinder 401 compresses the upper oil chamber, the generated high-pressure oil enters the oil inlet of the main oil circuit 2 through the first one-way valve assembly 501. It then passes through the proportional valve 3, the high-pressure accumulator 6, and the pressure sensor 4 before reaching the oil outlet of the main oil circuit 2. The two solenoid valves are opened or closed based on the circuit flow rate. When the circuit flow rate exceeds 400 L / min, it is determined to be a high circuit flow rate, and the first solenoid valve 601 is opened. The high-pressure oil passes through the first speed regulating valve 701 and then flows through the first hydraulic motor 901, where hydraulic energy is converted into rotational mechanical energy. The first generator 801 then converts the mechanical energy into electrical energy for power generation. When the circuit flow rate is less than 400 L / min, it is considered a low circuit flow rate. At this point, the second solenoid valve 602 opens, and the high-pressure oil passes through the second speed regulating valve 702 and then the second hydraulic motor 902, converting the hydraulic energy into rotational mechanical energy. The second generator 802 then converts the mechanical energy into electrical energy for power generation. Similarly, when the piston rod of the first hydraulic cylinder 401 compresses the lower oil chamber, the generated high-pressure oil enters the main oil circuit 2 inlet through the one-way valve assembly, passes through the proportional valve 3, the high-pressure accumulator 6, and the pressure sensor 4, and reaches the main oil circuit 2 outlet. The two solenoid valves are then opened or closed based on the circuit flow rate.

[0058] The working principles of the second float 302 and the second hydraulic cylinder 402 are the same as above.

[0059] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A hydraulic power output system, characterized in that: It includes a float, a hydraulic cylinder, a main oil circuit, an oil tank and a power generation component. The float is used to float on the sea surface and is connected to the piston rod of the hydraulic cylinder. The upper oil chamber and the lower oil chamber of the hydraulic cylinder are both connected to the oil inlet of the main oil circuit and the oil tank. The oil outlet of the main oil circuit is connected to the power generation component. There are multiple groups of power generation components, and the multiple groups of power generation components are used to generate electricity under different wave conditions. A high-pressure accumulator is also provided on the main oil circuit, and the high-pressure accumulator is connected in series with a proportional valve.

2. The hydraulic power output system according to claim 1, characterized in that: Any group of the power generation components includes a working oil circuit, a solenoid valve, a hydraulic motor and a generator. The oil inlet of the working oil circuit is connected to the oil outlet of the main oil circuit, and the oil outlet of the working oil circuit is connected to the oil tank. The solenoid valve and the hydraulic motor are arranged in sequence on the working oil circuit, and the hydraulic motor is used to drive the generator to generate electricity.

3. The hydraulic power output system according to claim 1, characterized in that: The working pressure of the high-pressure accumulator is 25-35 MPa, and a pressure sensor is also provided on the main oil circuit.

4. The hydraulic power output system according to claim 1, characterized in that: There are multiple hydraulic cylinders, which are distributed in an array, and the piston rod of any hydraulic cylinder is connected to a float.

5. The hydraulic power output system according to claim 1 or 4, characterized in that: The upper oil chamber and the lower oil chamber of the hydraulic cylinder are connected to the main oil circuit and the oil tank through a one-way valve group.

6. The hydraulic power output system according to claim 2, characterized in that: The power generation component is provided with two groups, including a first power generation component and a second power generation component, wherein the first power generation component includes a first working oil circuit, a first solenoid valve, a first hydraulic motor and a first generator, the oil inlet of the first working oil circuit is connected to the oil outlet of the main oil circuit, the oil outlet of the first working oil circuit is connected to the oil tank, the first solenoid valve and the first hydraulic motor are arranged in sequence on the first working oil circuit, and the first hydraulic motor is used to drive the first generator to generate electricity; the second power generation component includes a second working oil circuit, a second solenoid valve, a second hydraulic motor and a second generator, the oil inlet of the second working oil circuit is connected to the oil outlet of the main oil circuit, the oil outlet of the second working oil circuit is connected to the oil tank, the second solenoid valve and the second hydraulic motor are arranged in sequence on the second working oil circuit, and the second hydraulic motor is used to drive the second generator to generate electricity.

7. The hydraulic power output system according to claim 6, characterized in that: When the circuit flow rate is greater than 400L / min, the first solenoid valve is opened and the displacement of the first hydraulic motor is 800cm 3 / rev, the rotation speed is 1200rpm, and the rated load of the first generator is 200kW; When the circuit flow rate is less than 400L / min, the second solenoid valve is opened and the displacement of the second hydraulic motor is 250cm 3 / rev, the rotation speed is 1600rpm, and the rated load of the second generator is 50kW.

8. The hydraulic power output system according to claim 2 or 6, characterized in that: The generator is a three-phase permanent magnet synchronous generator.

9. The hydraulic power output system according to claim 2 or 6, characterized in that: A speed regulating valve is also provided on the working oil circuit.

10. The hydraulic power output system according to claim 1, characterized in that: The main oil line is also provided with an overflow valve.

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