Wave power generation hydraulic system and control method thereof

Abstract

The invention relates to the technical field of hydraulic pressure, in particular to a wave energy power generation hydraulic system and a control method thereof.The wave energy power generation hydraulic system comprises a closed hydraulic loop, and a hydraulic motor, a power generator, a flush valve and at least one hydraulic cylinder which are communicated are arranged in the closed hydraulic loop; the hydraulic cylinder converts wave energy collected by the floater into pressure potential energy and conveys the pressure potential energy to the hydraulic motor, the hydraulic motor drives the electric generator to generate electricity through the pressure potential energy, the flushing valve is used for replacing hydraulic oil in the hydraulic loop, and the hydraulic loop located between the hydraulic cylinder and the input end of the hydraulic motor is communicated with a high-pressure energy accumulator. The high-pressure energy accumulator is used for storing excess energy in the large-wave environment and releasing the excess energy to the hydraulic motor in the small-wave environment. According to the invention, wave energy under low energy flow density can be converted; the wave environment is adapted, and different power generation modes are switched according to different incident wave energy; hydraulic oil in the system is replaced through the cleaning valve, and the purposes of cooling and dirt removal are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulics, and particularly relates to a wave energy power generation hydraulic system and a control method thereof. Background Art

[0002] At present, China ranks first in the world in terms of total energy production, total energy consumption, coal production, and thermal power installed capacity. However, China's energy resources are still characterized by "rich coal, less oil, and scarce gas". In the proportion of the primary energy structure in recent years in China, coal and oil are still the main energy sources. The large-scale exploitation of traditional fossil energy has brought a series of problems such as energy reserve crisis, global warming, and air pollution. Fortunately, the proportion of non-fossil energy has been increasing year by year in recent years, reflecting the steady progress of China's green and low-carbon energy transformation. Although China's energy utilization efficiency is constantly improving and the energy structure is constantly optimizing, the proportion of thermal power consumption is large, and the problems of consumption and management of green clean energies such as solar energy, wave energy, and wind energy are still prominent. Meeting energy demands and carrying out energy transformation have become the consensus of the whole society. Developing renewable energy and increasing the proportion of green energy are important measures to solve energy problems.

[0003] As an important renewable energy, the reasonable development and utilization of ocean energy is an important way to achieve the "dual carbon" goal and an important development direction for promoting the construction of a maritime power. Wave energy has become the focus of ocean energy research and development due to its advantages such as huge reserves, high energy flux density, strong sustainability, and small environmental impact. However, compared with mature renewable energy technologies such as solar energy and wind energy, wave energy power generation technology is still in its infancy. The PTO (power take-off) system is a mechanism that converts the energy captured by the wave absorber into usable electrical energy and is one of the key components of wave energy power generation devices. At present, researchers and developers have proposed various PTO systems, such as those based on air turbines, water turbines, direct mechanical drive systems, direct electric drive systems, and hydraulic drive systems. Among them, the hydraulic PTO system is an ideal system for low-frequency, high-power density waves and is very suitable for wave energy power generation occasions.

[0004] China's wave energy resources are different from those in European seas with long wave periods and large wave heights. Instead, they show short periods and small wave heights, making it difficult to drive high-power units. Even if driven, the power generation duration is very short, and the power output is significantly discontinuous. Using small-power units to capture energy is not sufficient to fully utilize wave energy resources. Therefore, it is of great significance to develop a hydraulic PTO system that can adapt to different wave resource characteristics, especially for wave energy capture and conversion under low energy flux density in China.

[0005] In addition, as the waves undulate and surge, the wave energy power generation device will continuously operate at sea. The temperature of the hydraulic oil in the hydraulic PTO system will gradually rise, and there is a risk of leakage. Many grindings will also be generated in the hydraulic oil due to the movement of the mechanical structure, affecting the power generation performance. Therefore, the hydraulic PTO system needs to supplement the leakage of hydraulic oil in the system, flush the dirt particles, and reduce the temperature of the hydraulic oil. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a wave energy power generation hydraulic system and its control method.

[0007] To solve the above technical problem, the technical solution adopted by the present invention is: a wave energy power generation hydraulic system, in which a connected hydraulic motor, a generator, a flushing valve, and at least one hydraulic cylinder are arranged in the closed hydraulic circuit. The hydraulic cylinder converts the wave energy collected by the float into pressure potential energy and transports it to the hydraulic motor. The hydraulic motor uses the pressure potential energy to drive the generator to generate electricity. The flushing valve is used to replace the hydraulic oil in the hydraulic circuit. A high-pressure accumulator is connected to the hydraulic circuit between the hydraulic cylinder and the input end of the hydraulic motor. The high-pressure accumulator is used to store the excess energy in a large wave environment and release it to the hydraulic motor during small waves.

[0008] Preferably, a make-up oil module is further arranged in the closed hydraulic circuit. The make-up oil module is connected to the hydraulic circuit through a first make-up oil check valve and a second make-up oil check valve. The make-up oil module includes a motor, a make-up oil pump, a fine filter, a make-up oil overflow valve, a first oil tank, and a second oil tank. The first oil tank is connected to the first make-up oil check valve through the make-up oil overflow valve. The second oil tank is connected to the second make-up oil check valve through the make-up oil pump. A first fine filter is arranged between the second make-up oil check valve and the make-up oil pump. The motor is used to drive the make-up oil pump to work.

[0009] Preferably, a pressure stabilizing energy storage module and a first overflow valve are respectively connected to the hydraulic circuit between the hydraulic cylinder and the high-pressure accumulator. The input end of the pressure stabilizing energy storage module is connected to the hydraulic circuit through a two-position three-way directional valve. A second overflow valve is arranged between the output end of the pressure stabilizing energy storage module and the input end of the high-pressure accumulator.

[0010] Preferably, a low-pressure accumulator is connected to the hydraulic circuit between the flushing valve and the output end of the hydraulic motor. The low-pressure accumulator is used to collect the hydraulic oil flowing out of the low-pressure side of the hydraulic motor.

[0011] Preferably, a safety valve is arranged between the output end of the high-pressure accumulator and the hydraulic motor.

[0012] Preferably, an electro-hydraulic proportional overflow speed regulating valve is arranged between the output end of the high-pressure accumulator and the hydraulic motor.

[0013] Preferably, a second fine filter is provided behind the output end of the hydraulic motor in the hydraulic circuit.

[0014] Preferably, the flushing valve is connected to a flushing oil tank, and a third overflow valve is provided between the flushing oil tank and the flushing valve.

[0015] Preferably, a rectifying valve block is provided between the hydraulic cylinder and the main circuit.

[0016] The present invention also provides a control method for a wave energy power generation hydraulic system, including: Obtaining the operating state data of the wave energy power generation hydraulic system; According to the operating state data, changing the operating mode of the wave energy power generation hydraulic system; Specifically: When the pressure P of the first pressure gauge 5.1 is not greater than the charging pressure P of the high-pressure accumulator M1 the hydraulic oil flows through the voltage stabilizing energy storage module, and the system is in the energy storage power generation mode of the over-voltage stabilizing energy storage module. After the energy storage reaches the release pressure P of the high-pressure accumulator S1 it is released for power generation; When the pressure P of the first pressure gauge 5.1 is greater than the charging pressure P of the high-pressure accumulator M1 but less than 2 times the release pressure P of the high-pressure accumulator S1 2 times the release pressure of the high-pressure accumulator is denoted as P M2 the system is in the energy storage power generation mode without passing through the voltage stabilizing energy storage module; When the pressure P of the first pressure gauge 5.1 is greater than the ultimate working pressure P of the hydraulic motor M3 the system is in the unloading mode; When P M2 <P 5.1 <P M3 it indicates that the wave condition is good, and the system is in the continuous power generation mode without passing through the voltage stabilizing energy storage module.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention can convert wave energy under low energy flux density; (2) It adapts to different wave conditions and switches different power generation modes according to different incident wave energies; (3) The hydraulic oil in the system is replaced through the cleaning valve to achieve the purposes of cooling and decontamination. Brief Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the wave energy power generation hydraulic system according to an embodiment of the present invention.

[0019] Figure 2This is the schematic diagram of the oil replenishment module according to the embodiment of the present invention.

[0020] Figure 3 This is the schematic diagram of different operating modes according to the embodiment of the present invention.

[0021] Markings in the figure: 1.1 First hydraulic cylinder; 1.2 Second hydraulic cylinder; 1.3 Third hydraulic cylinder; 2.1 First electromagnetic directional control valve; 2.2 Second electromagnetic directional control valve; 2.3 Third electromagnetic directional control valve; 3.1 First rectifier valve block; 3.2 Second rectifier valve block; 3.3 Third rectifier valve block; 4.1 First flowmeter; 5.1 First pressure gauge; 5.2 Second pressure gauge; 5.3 Third pressure gauge; 5.4 Fourth pressure gauge; 6 Two-position three-way directional control valve; 7 High-pressure accumulator; 8.1 First electromagnetic shut-off valve; 8.2 Second electromagnetic shut-off valve; 9 Electro-hydraulic proportional overflow speed control valve; 10 Hydraulic motor; 11 Generator; 12.1 Third check valve; 12.2 First oil replenishment check valve; 12.3 Second oil replenishment check valve; 13 Safety valve; 14 Low-pressure accumulator; 15 Voltage stabilizing energy storage module; 16 Oil replenishment module; 1604 Oil replenishment overflow valve; 1603 First fine filter; 1602 Oil replenishment pump; 1601 Electric motor; 17.1 First overflow valve; 17.2 Second overflow valve; 17.3 Third overflow valve; 18 Flushing valve; 19.1 First oil tank; 19.2 Second oil tank; 19.3 Flushing oil tank; 20 Second fine filter; 21 Emergency interface. Detailed implementation manners

[0022] In order to make the above features and advantages of the present invention more obvious and understandable, specific embodiments are hereinafter given and described in detail in conjunction with the accompanying drawings.

[0023] As Figures 1 to 2 shown, a wave energy power generation hydraulic system, a hydraulic motor 10, a generator 11, a flushing valve 18 and three hydraulic cylinders are arranged in the closed hydraulic circuit. The hydraulic cylinders convert the wave energy collected by the floats into pressure potential energy and transport it to the hydraulic motor 10. The hydraulic motor 10 uses the pressure potential energy to drive the generator 11 to generate electricity. The flushing valve 18 is used to replace the hydraulic oil in the hydraulic circuit. A high-pressure accumulator 7 is connected to the hydraulic circuit between the hydraulic cylinders and the input end of the hydraulic motor 10. The high-pressure accumulator 7 is used to store the excess energy in a large wave environment and release it to the hydraulic motor 10 in a small wave.

[0024] The three hydraulic cylinders include a first hydraulic cylinder 1.1, a second hydraulic cylinder 1.2, and a third hydraulic cylinder 1.3. A first electromagnetic directional valve 2.1 and a first rectifier valve block 3.1 are provided at the first hydraulic cylinder 1.1. A second electromagnetic directional valve 2.2 and a second rectifier valve block 3.2 are provided at the second hydraulic cylinder 1.2. A third electromagnetic directional valve 2.3 and a third rectifier valve block 3.3 are provided at the third hydraulic cylinder 1.3. In this closed hydraulic circuit, the two ports of each electromagnetic directional valve are respectively connected to the rod chamber and the rodless chamber of the corresponding hydraulic cylinder, and then the other two ports of the electromagnetic directional valve are connected to the corresponding rectifier valve block. After the hydraulic oil is rectified and collected with the input hydraulic oil of other hydraulic cylinders, it flows into the hydraulic circuit.

[0025] A first flowmeter 4.1 and a first pressure gauge 5.1 are provided between the output end where the hydraulic circuit and each hydraulic cylinder converge. The first flowmeter 4.1 and the pressure gauge 5.1 respectively measure the flow rate and pressure after convergence.

[0026] In this embodiment, a make-up oil module 16 is further provided in the closed hydraulic circuit. The make-up oil module 16 is connected to the hydraulic circuit through a first make-up oil check valve 12.2 and a second make-up oil check valve 12.3. The make-up oil module 16 includes a motor 1601, a make-up oil pump 1602, a first fine filter 1603, a make-up oil overflow valve 1604, a first fuel tank 19.1, and a second fuel tank 19.2. The first fuel tank 19.1 is connected to the first make-up oil check valve 12.2 through the make-up oil overflow valve 1604. The second fuel tank 19.2 is connected to the second make-up oil check valve 12.3 through the make-up oil pump 1602. A first fine filter 1603 is provided between the second make-up oil check valve 12.3 and the make-up oil pump 1602. The motor 1601 is used to drive the make-up oil pump 1602 to work.

[0027] The make-up oil module 16 is used for oil filling, air replacement, hydraulic oil cooling, and make-up oil after system leakage of the hydraulic circuit to avoid phenomena such as cavitation, vibration, and noise in the hydraulic system. When the pressure on the hydraulic circuit is lower than the working pressure within a certain range, the make-up oil module 16 is started through the control program until the set size of the overflow valve limits the make-up oil pump 1602 from overpressuring the oil supply.

[0028] During the device commissioning stage, oil filling and air replacement of the hydraulic circuit are carried out through the make-up oil module 16, so as to supplement the hydraulic oil lost due to leakage in the hydraulic circuit and replace the air in the hydraulic circuit.

[0029] In this embodiment, a pressure stabilizing energy storage module 15 and a first overflow valve 17.1 are respectively connected in communication on the hydraulic circuit between the hydraulic cylinder and the high-pressure accumulator 7. The input end of the pressure stabilizing energy storage module 15 is connected to the hydraulic circuit through a two-position three-way directional control valve 6, and a second overflow valve 17.2 is provided between the output end of the pressure stabilizing energy storage module 15 and the input end of the high-pressure accumulator 7.

[0030] A first electromagnetic shut-off valve 8.1 is provided between the high-pressure accumulator 7 and the hydraulic circuit, and a second pressure gauge 5.2 for measuring the pressure at the output end of the high-pressure accumulator 7 is also provided on the hydraulic circuit.

[0031] The first overflow valve 17.1 is used to set the maximum working pressure of the entire circuit system, and the two-position three-way directional control valve 6 is used to realize whether the hydraulic oil passes through the pressure stabilizing energy storage module 15. The high-pressure accumulator 7 absorbs the pulses of the waves, stores the excess energy under large waves, releases the stored energy during small waves to make the generator reach the rated state, and smooths the output power of the generator in the continuous power generation mode; the high-pressure accumulator 7 stores a certain amount of hydraulic oil until the pressure is released and then outputs to drive the generator 11 to work in the energy storage power generation mode.

[0032] In this embodiment, a low-pressure accumulator 14 is connected in communication on the hydraulic circuit between the flushing valve 18 and the output end of the hydraulic motor 10. The low-pressure accumulator 14 is used to collect the hydraulic oil flowing out from the low-pressure side of the hydraulic motor 10.

[0033] A second electromagnetic shut-off valve 8.2 is provided between the low-pressure accumulator 14 and the hydraulic circuit.

[0034] In this embodiment, a safety valve 13 is provided between the output end of the high-pressure accumulator 7 and the hydraulic motor 10. The safety valve 13 is used for unloading during the approach of severe sea conditions, before the device is deployed or withdrawn, and the entire system does not generate electricity.

[0035] In this embodiment, an electro-hydraulic proportional overflow speed control valve 9 is provided between the output end of the high-pressure accumulator 7 and the hydraulic motor 10. The electro-hydraulic proportional overflow speed control valve 9 is used to adjust the flow rate impacting the hydraulic motor, especially when it is necessary to change the flow rate size for comparative analysis of power generation during the onshore and offshore test stages of the device, and it can also be used as the control object for power maximization tracking.

[0036] A second flow meter 4.2 and a third pressure gauge 5.3 are provided between the electro-hydraulic proportional overflow speed control valve 9 and the input end of the hydraulic motor. After the flow rate is adjusted, the flow rate and pressure entering the hydraulic motor 10 are measured by the second flow meter 4.2 and the third pressure gauge 5.3.

[0037] A fourth pressure gauge 5.4 is provided at the output end of the hydraulic motor. The fourth pressure gauge 5.4 is used to measure the pressure at the rear end of the hydraulic motor 10. The pressure difference during the operation of the hydraulic motor is measured based on the third pressure gauge 5.3 and the fourth pressure gauge 5.4. Since whether the generator reaches the rated power generation state depends on the pressure difference between the front and rear ends of the motor and the input flow rate.

[0038] In this embodiment, a second fine filter 20 is provided behind the output end of the hydraulic motor 10 in the hydraulic circuit. The second fine filter 20 filters the hydraulic oil output by the hydraulic motor 10, the safety valve 13, and the second overflow valve 17.2. The filtered hydraulic oil flows into the low-pressure accumulator 14 through the second electromagnetic shut-off valve 8.2, and at the same time is connected to the output end of the first overflow valve 17.1, and finally returns to the hydraulic cylinder through the rectifying valve block 3.

[0039] In this embodiment, the flushing valve 18 is connected to a flushing oil tank 19.3, and a third overflow valve 17.3 is provided between the flushing oil tank 19.3 and the flushing valve 18.

[0040] After working for a period of time, the oil temperature in the system rises and pollutants such as grinding debris increase. By starting the oil replenishment module 16 and the flushing valve 18, the high-temperature oil or contaminated oil in the closed hydraulic circuit is replaced, so as to cool the hydraulic oil in the hydraulic circuit and clean the grinding debris and other dirt stored in the hydraulic circuit.

[0041] After the wave acts on the energy-harvesting floating body in the present invention, the float converts the wave energy into the kinetic energy of its own movement, thereby driving the connected hydraulic cylinder to move. The hydraulic oil output by multiple hydraulic cylinders converges and then passes through a two-position three-way directional control valve 6. At the flow rate set by the electro-hydraulic proportional overflow speed control valve 9, the hydraulic oil is finally input into the hydraulic motor 10 to drive the generator 11 to generate electricity.

[0042] When the electro-hydraulic proportional overflow speed control valve 9 sets its opening to 0 through the controller, the hydraulic oil can choose whether to flow through the pressure stabilizing energy storage module 15 after converging through the two-position three-way directional control valve 6. Whether it flows through the pressure stabilizing energy storage module 15 or not, the power generation mode of the entire system is the energy storage power generation mode. It stores the input hydraulic energy in the high-pressure accumulator 7 until the accumulator 7 reaches the set pressure value, and then the opening of the electro-hydraulic proportional overflow speed control valve 9 is adjusted to a certain opening so that the output power of the generator 11 meets the rated power generation state, and the hydraulic oil in the high-pressure accumulator 7 is released for power generation.

[0043] When the electro-hydraulic proportional overflow speed control valve 9 can also be set to the normally open state through the controller, and the hydraulic oil does not pass through the voltage-stabilizing energy storage module 15 via the two-position three-way directional control valve 6, the power generation mode of the entire system is the continuous power generation mode. The high-pressure accumulator 7 is used to absorb the fluctuations of the hydraulic energy caused by the wave changes. When the wave energy increases, the accumulator stores the excess energy. When the wave energy decreases, the accumulator releases the energy, so as to make the power output of the generator as smooth as possible. In order to make the output power of the generator 11 as large as possible, in this mode, the controller can still adjust the opening degree of the electro-hydraulic proportional overflow speed control valve 9 according to the wave conditions, so as to adjust the hydraulic oil flow rate of the hydraulic motor 10 during the continuous power generation process.

[0044] The energy storage power generation mode can be used when the wave energy is in a low energy flux density for a long time and cannot meet the rated power generation of the generator; while the continuous power generation mode can be used when the wave energy is in a high energy flux density for a long time and the generator can continuously output a wave condition close to the rated power.

[0045] The two-position three-way directional control valve 6 is used to adjust whether the system passes through the voltage-stabilizing energy storage module 15. When the wave energy is very small and the nitrogen charging pressure of the high-pressure accumulator 7 is much higher than the input pressure of the hydraulic oil, the thrust of the hydraulic cylinder cannot push the high-pressure accumulator at the rear end, and the hydraulic cylinder is in a "locked" state. The hydraulic oil cannot be stored in the high-pressure accumulator 7. In this case, the voltage-stabilizing energy storage module 15 can amplify the wave energy under the action of micro-amplitude waves, and then slowly store the wave energy into the accumulator until the pressure for the accumulator to release power generation is reached. The selection of the voltage-stabilizing energy storage module 15 enables the power generation mode of the entire system to be further divided into four types: the energy storage power generation mode passing through the voltage-stabilizing energy storage module, the continuous power generation mode passing through the voltage-stabilizing energy storage module, the energy storage power generation mode not passing through the voltage-stabilizing energy storage module, and the continuous power generation mode not passing through the voltage-stabilizing energy storage module. Among them, there is a large amount of energy dissipation in the continuous power generation mode passing through the voltage-stabilizing energy storage module 15. Therefore, this mode is not considered in the actual sea condition working state of this system.

[0046] In addition, in extremely harsh sea conditions such as typhoons and tsunamis, the device structure will be subjected to very large wave forces. At this time, the converging pressure of the hydraulic oil will exceed the working pressure of the system, and the generator 11 will be in an overload operation state. In this sea condition, the device structure and the entire oil pressure transmission system will face severe tests. Therefore, this hydraulic system does not generate electricity in this sea condition to avoid damage to the device structure and the system caused by harsh sea conditions. This mode is the unloading mode. At this time, the electro-hydraulic proportional overflow speed control valve 9 sets its opening to 0 through the controller, and the safety valve 13 is in the normally open state.

[0047] When system maintenance is required or the hydraulic cylinder does not move under severe sea conditions, the emergency interface 21 at the rear end of the hydraulic cylinder is an oil circuit emergency interface reserved for connecting to the emergency system. Close the electromagnetic directional valve 2 and connect to the emergency interface 21 through an external emergency system to control the left and right movement of the hydraulic cylinder, so as to realize the lifting or lowering of the energy capture float.

[0048] In this embodiment, the hydraulic circuit is also provided with an i-port of the high-pressure circuit and a j-port of the low-pressure circuit. The i-port of the high-pressure circuit and the j-port of the low-pressure circuit are used for connecting the oil ports of more hydraulic cylinders, so as to realize the power generation by aggregating multiple hydraulic cylinders in the system.

[0049] The main features of the present invention are as follows: (1) The hydraulic cylinder in the hydraulic system is of the single-rod double-acting type, which can perform work in double strokes and fully capture wave energy; this hydraulic system can aggregate the energy converted by multiple hydraulic cylinders, realizing the transfer and conversion of wave energy captured by multiple floating bodies and multiple degrees of freedom of the device; the high-pressure and low-pressure sides of the system are respectively provided with aggregation input and output interfaces, making the system have strong expandability and enabling the distributed array networking of the device.

[0050] (2) The hydraulic PTO system is a closed-loop system, which can effectively utilize the hydraulic oil flowing out of the low-pressure side of the motor. Compared with the open-loop circuit, the hydraulic oil output from the low-pressure side of the motor no longer flows back to the fuel tank, reducing energy loss. At the same time, it provides a certain back pressure for the motor to prevent the high-pressure oil at the input end of the motor from causing a large impact on it.

[0051] (3) This hydraulic PTO system can adjust the power generation mode according to wave conditions. When the wave conditions are good, it is in the continuous power generation mode, and the high-pressure accumulator plays the role of "shaving peaks and filling valleys"; when the wave conditions are average, it is in the energy storage power generation mode, and the energy is accumulated to a certain pressure and then released for power generation. Even when the waves are scarce, such as when there are gentle waves, the system can still store the wave energy under low energy flux density in the accumulator for power generation. This hydraulic PTO system has multiple power generation modes, broadening the capture frequency band width of waves.

[0052] (4) The setting of the flushing valve 18 and the oil replenishment module 16 in the system can replace the hydraulic oil in the system and has the functions of cooling and cleaning dirt.

[0053] As Figures 1 to 3 shown, the present invention also provides a control method for a wave energy power generation hydraulic system, including: Obtaining the operation state data of the wave energy power generation hydraulic system; According to the operation state data, changing the operation mode of the wave energy power generation hydraulic system; Specifically: When the pressure P of the first pressure gauge 5.15.1 not greater than the charging pressure P of the high-pressure accumulator 7 M1 When this is the case, the hydraulic oil flows through the voltage-stabilizing energy storage module, and the system is in the energy storage and power generation mode of the over-voltage-stabilizing energy storage module 15. Energy storage reaches the release pressure P of the high-pressure accumulator 7 S1 and then releases power generation; When the pressure P of the first pressure gauge 5.1 5.1 is greater than the charging pressure P of the high-pressure accumulator 7 M1 , but less than 2 times the release pressure P of the high-pressure accumulator 7 S1 At this time, 2 times the release pressure of the high-pressure accumulator 7 is denoted as P M2 , and the system is in the energy storage and power generation mode of the non-over-voltage-stabilizing energy storage module 15; When the pressure P of the first pressure gauge 5.1 5.1 is greater than the ultimate working pressure P of the hydraulic motor M3 At this time, the system is in the unloading mode; When P M2 <P 5.1 <P M3 At this time, it indicates that the wave condition is good, and the system is in the continuous power generation mode of the non-over-voltage-stabilizing energy storage module 15.

[0054] The above is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Any person skilled in the art who has not departed from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention shall fall within the scope covered by the present invention.

Claims

1. A wave energy power generation hydraulic system, comprising a closed hydraulic circuit, characterized in that: The closed hydraulic circuit is provided with a connected hydraulic motor, a generator, a flushing valve and at least one hydraulic cylinder. The hydraulic cylinder converts the wave energy collected by the float into pressure potential energy and transmits it to the hydraulic motor. The hydraulic motor drives the generator to generate electricity using the pressure potential energy. The flushing valve is used to replace the hydraulic oil in the hydraulic circuit. A high-pressure accumulator is connected to the hydraulic circuit between the hydraulic cylinder and the input end of the hydraulic motor. The high-pressure accumulator is used to store excess energy in a large wave environment and release it to the hydraulic motor when the waves are small.

2. The wave energy power generation hydraulic system according to claim 1, characterized in that: The closed hydraulic circuit is also provided with an oil replenishment module, and the oil replenishment module is connected to the hydraulic circuit through a first oil replenishment check valve and a second oil replenishment check valve. The oil replenishment module includes an electric motor, an oil replenishment pump, a fine oil filter, an oil replenishment overflow valve, a first oil tank and a second oil tank. The first oil tank is connected to the first oil replenishment check valve through the oil replenishment overflow valve, and the second oil tank is connected to the second oil replenishment check valve through the oil replenishment pump. A first fine oil filter is provided between the second oil replenishment check valve and the oil replenishment pump, and the electric motor is used to drive the oil replenishment pump to work.

3. The wave energy power generation hydraulic system according to claim 1, characterized in that: A pressure-stabilizing energy storage module and a first overflow valve are respectively connected to the hydraulic circuit between the hydraulic cylinder and the high-pressure accumulator. The input end of the pressure-stabilizing energy storage module and the hydraulic circuit are connected via a two-position three-way reversing valve. A second overflow valve is arranged between the output end of the pressure-stabilizing energy storage module and the input end of the high-pressure accumulator.

4. The wave energy power generation hydraulic system according to claim 1, characterized in that: A low-pressure accumulator is connected to the hydraulic circuit between the flushing valve and the output end of the hydraulic motor. The low-pressure accumulator is used to collect the hydraulic oil flowing out of the low-pressure side of the hydraulic motor.

5. The wave energy power generation hydraulic system according to claim 1, characterized in that: A safety valve is arranged between the output end of the high-pressure accumulator and the hydraulic motor.

6. The wave energy power generation hydraulic system according to claim 1, characterized in that: An electro-hydraulic proportional overflow speed regulating valve is arranged between the output end of the high-pressure accumulator and the hydraulic motor.

7. The wave energy power generation hydraulic system according to claim 1, characterized in that: The hydraulic circuit is provided with a second fine oil filter behind the output end of the hydraulic motor.

8. The wave energy power generation hydraulic system according to claim 1, characterized in that: The flushing valve is connected to a flushing oil tank, and a third overflow valve is arranged between the flushing oil tank and the flushing valve.

9. The wave energy power generation hydraulic system according to claim 1, characterized in that: A rectifying valve block is arranged between the hydraulic cylinder and the main circuit.

10. A control method based on the wave energy power generation hydraulic system according to claim 1, characterized in that: include: Obtaining the operating status data of the wave energy generation hydraulic system; According to the operating status data, changing the operating mode of the wave energy power generation hydraulic system; Specifically: When the pressure P of the first pressure gauge 5.1 Not greater than the charging pressure P of the high-pressure accumulator M1 When the hydraulic oil flows through the voltage-stabilizing energy storage module, the system is in the energy storage and power generation mode of the voltage-stabilizing energy storage module, and the energy storage reaches the release pressure P of the high-pressure accumulator. S1 Post-release power generation; When the pressure P of the first pressure gauge 5.1 Greater than the charging pressure P of the high-pressure accumulator M1 , but less than 2 times the release pressure P of the high pressure accumulator S1 When the release pressure of the 2-fold high-pressure accumulator is recorded as P M2 , the system is in the energy storage and power generation mode without voltage-stabilizing energy storage module; When the pressure of the first pressure gauge Greater than the hydraulic motor's limit working pressure P M3 When , the system is in unloading mode; When P M2 < < When , it indicates that the wave condition is good and the system is in the continuous power generation mode of the voltage-stabilizing energy storage module.

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