A wave energy power generation hydraulic system and control method thereof

Abstract

The present invention relates to the field of hydraulic technology, and more specifically to a wave energy power generation hydraulic system and a control method thereof. The wave energy power generation hydraulic system includes a closed hydraulic circuit, in which a hydraulic motor, a generator, a flushing valve, and at least one hydraulic cylinder are connected. The hydraulic cylinder converts wave energy collected by a float into pressure potential energy and transmits 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 displace 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. The present invention can convert wave energy under low energy flux density; adapt to the wave environment and switch different power generation modes according to different incident wave energies; and displace the hydraulic oil in the system through the flushing valve to achieve the purpose of cooling and decontamination.

Description

Technical Field

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

[0002] Currently, my country leads the world in total energy production, total consumption, coal production, and installed thermal power capacity. However, my country's energy resources are still endowed with a "rich coal, limited oil, and scarce gas" profile. In recent years, coal and oil have remained the primary sources of energy in my country's primary energy mix. The extensive exploitation of traditional fossil fuels has led to a series of problems, including energy reserve crises, global warming, and air pollution. However, it is encouraging that the proportion of non-fossil energy has been increasing annually in recent years, reflecting the steady progress of my country's green and low-carbon energy transition. In 2022, the "14th Five-Year Plan for a Modern Energy System" and the "14th Five-Year Plan for Renewable Energy Development" were released, projecting that total renewable energy consumption would reach 1 billion tons of standard coal by 2025. Despite continuous improvements in energy efficiency and optimization of my country's energy structure, thermal power still accounts for a large proportion of consumption, and the absorption and management of green and clean energy sources such as solar, wave, and wind power remain prominent. Meeting energy demand and embarking on an energy transition have become a societal consensus. Developing renewable energy and increasing the proportion of green energy are key measures to address energy challenges.

[0003] As an important renewable energy source, the rational development and utilization of ocean energy is a crucial path to achieving the "dual carbon" goals and a key development direction for building a strong maritime nation. Wave energy, due to its vast reserves, high energy flux density, strong sustainability, and minimal environmental impact, has become a focus of ocean energy research and development. However, compared with mature renewable energy technologies such as solar and wind power, wave energy generation technology is still in its infancy. The PTO (power take-off) system, a mechanism that converts energy captured by an absorber into usable electrical energy, is a key component of wave energy generation devices. Currently, researchers and developers have proposed various PTO systems, including those based on air turbines, hydraulic turbines, direct mechanical drive systems, direct electric drive systems, and hydraulic drive systems. Hydraulic PTO systems are ideal for low-frequency, high-power-density waves and are therefore well-suited for wave energy generation applications.

[0004] my country's wave energy resources are different from those in European waters, where the waves have long periods and high wave heights. China's wave energy resources have short periods and small wave heights, making it difficult to drive high-power units. Even after being driven, the power generation time is very short, and the power output is obviously discontinuous. The use of small-power units for energy capture is not enough to fully utilize the wave energy resources. It is of great significance to develop a hydraulic PTO system that can adapt to the characteristics of different wave resources, especially for the capture and conversion of wave energy under low energy flux density in my country.

[0005] Furthermore, the constant ups and downs of waves and the continuous operation of wave energy generators at sea will gradually increase the temperature of the hydraulic oil in the hydraulic PTO system, posing a risk of leakage. The movement of the mechanical structure will also cause abrasion within the hydraulic oil, affecting power generation performance. Therefore, the hydraulic PTO system needs to replenish any leaked hydraulic oil, flush out any contaminants, and reduce the temperature of the hydraulic oil. Summary of the Invention

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

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a wave energy power generation hydraulic system, wherein 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 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, and 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.

[0008] Preferably, an oil replenishment module is further provided in the closed hydraulic circuit, 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, and 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.

[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 and the hydraulic circuit are connected through a two-position three-way reversing valve, and a second overflow valve is provided 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, and the low-pressure accumulator is used to collect hydraulic oil flowing out of the low-pressure side of the hydraulic motor.

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

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

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

[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 rectifier 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, comprising:

[0017] Obtaining operating status data of the wave energy generation hydraulic system;

[0018] changing the operating mode of the wave energy power generation hydraulic system according to the operating status data;

[0019] Specifically:

[0020] 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 pressure stabilizing energy storage module, the system is in the energy storage and power generation mode of the pressure stabilizing energy storage module, and the energy storage reaches the release pressure P of the high-pressure accumulator. S1 Post-release power generation;

[0021] 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 high-pressure accumulator is twice as high as P M2 , the system is in the energy storage and power generation mode without using the voltage stabilizing energy storage module;

[0022] When the pressure P of the first pressure gauge 5.1 Greater than the hydraulic motor's limit working pressure P M3 When , the system is in unloading mode;

[0023] When P M2 <P 5.1 <P M3 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.

[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) the present invention can convert wave energy at low energy flux density; (2) it can adapt to different wave conditions and switch to different power generation modes according to different incident wave energies; (3) the hydraulic oil in the system is replaced by a cleaning valve, thereby achieving the purpose of cooling and decontamination. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of a wave energy power generation hydraulic system according to an embodiment of the present invention.

[0026] Figure 2 2 is a schematic diagram of an oil replenishment module according to an embodiment of the present invention.

[0027] Figure 3 Schematic diagram of different operating modes of an embodiment of the present invention.

[0028] Markings in the figure: 1.1 first hydraulic cylinder; 1.2 second hydraulic cylinder; 1.3 third hydraulic cylinder; 2.1 first solenoid reversing valve; 2.2 second solenoid reversing valve; 2.3 third solenoid reversing valve; 3.1 first rectifier valve block; 3.2 second rectifier valve block; 3.3 third rectifier valve block; 4.1 first flow meter; 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 reversing valve; 7 high-pressure accumulator; 8.1 first solenoid shut-off valve; 8.2 second solenoid shut-off valve; 9 electro-hydraulic proportional overflow speed control valve; 10 Hydraulic motor; 11 generator; 12.1 third one-way valve; 12.2 first oil supply one-way valve; 12.3 second oil supply one-way valve; 13 safety valve; 14 low-pressure accumulator; 15 voltage-stabilizing energy storage module; 16 oil supply module; 1604 oil supply overflow valve; 1603 first fine oil filter; 1602 oil supply 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 oil filter; 21 emergency interface. DETAILED DESCRIPTION

[0029] In order to make the above features and advantages of the present invention more obvious and easy to understand, embodiments are given below with reference to the accompanying drawings for detailed description.

[0030] like Figures 1 to 2As shown, a wave energy power generation hydraulic system is provided in a closed hydraulic circuit, wherein a hydraulic motor 10, a generator 11, a flushing valve 18 and three hydraulic cylinders are connected. The hydraulic cylinder converts the wave energy collected by the float into pressure potential energy and transmits 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 cylinder and the input end of the hydraulic motor 10. The high-pressure accumulator 7 is used to store excess energy in a large wave environment and release it to the hydraulic motor 10 when the waves are small.

[0031] The three hydraulic cylinders include the first hydraulic cylinder 1.1, the second hydraulic cylinder 1.2, and the third hydraulic cylinder 1.3. The first hydraulic cylinder 1.1 is equipped with a first solenoid reversing valve 2.1 and a first rectifier valve block 3.1. The second hydraulic cylinder 1.2 is equipped with a second solenoid reversing valve 2.2 and a second rectifier valve block 3.2. The third hydraulic cylinder 1.3 is equipped with a third solenoid reversing valve 2.3 and a third rectifier valve block 3.3. In this closed hydraulic circuit, two ports of each solenoid reversing valve are connected to the rod chamber and rodless chamber of the corresponding hydraulic cylinder, respectively. The other two ports of the solenoid reversing valve are then connected to the corresponding rectifier valve block. After rectification, the hydraulic oil is combined with the input hydraulic oil from the other hydraulic cylinders and flows into the hydraulic circuit.

[0032] A first flow meter 4.1 and a first pressure gauge 5.1 are provided between the hydraulic circuit and the output ends of the hydraulic cylinders to measure the flow rate and pressure after the hydraulic circuit is collected.

[0033] In this embodiment, an oil replenishment module 16 is further provided in the closed hydraulic circuit. The oil replenishment module 16 is connected to the hydraulic circuit via a first oil replenishment check valve 12.2 and a second oil replenishment check valve 12.3. The oil replenishment module 16 includes a motor 1601, an oil replenishment pump 1602, a first fine oil filter 1603, an oil replenishment relief valve 1604, and a first oil tank 19.1 and a second oil tank 19.2. The first oil tank 19.1 is connected to the first oil replenishment check valve 12.2 via the oil replenishment relief valve 1604, and the second oil tank 19.2 is connected to the second oil replenishment check valve 12.3 via the oil replenishment pump 1602. A first fine oil filter 1603 is provided between the second oil replenishment check valve 12.3 and the oil replenishment pump 1602. The motor 1601 is used to drive the oil replenishment pump 1602 to operate.

[0034] The oil replenishment module 16 is used to pump oil into the hydraulic circuit, displace air, cool the hydraulic oil, and replenish oil after system leaks to prevent cavitation, vibration, and noise in the hydraulic system. When the pressure in the hydraulic circuit falls below a certain range from the operating pressure, the control program activates the oil replenishment module 16 until the adjusted relief valve size limits the oil replenishment pump 1602 from over-pressure supply.

[0035] During the device debugging phase, the oil replenishment module 16 is used to pump oil and replace air in the hydraulic circuit, thereby replenishing the hydraulic oil lost due to leakage in the hydraulic circuit and replacing the air in the hydraulic circuit.

[0036] In this embodiment, a pressure-stabilizing energy storage module 15 and a first relief valve 17.1 are respectively connected to 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 via a two-position three-way reversing valve 6. A second relief 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.

[0037] A first electromagnetic shut-off valve 8.1 is provided between the high-pressure accumulator 7 and the hydraulic circuit. 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.

[0038] The first overflow valve 17.1 is used to adjust the maximum working pressure of the entire circuit system, and the two-position three-way reversing valve 6 is used to determine whether the hydraulic oil passes through the pressure stabilizing energy storage module 15.

[0039] In the continuous power generation mode, the high-pressure accumulator 7 absorbs wave pulses, stores excess energy under large waves, and releases the stored energy during small waves to enable the generator to reach the rated state, thereby smoothing the generator's output power. In the energy storage power generation mode, the high-pressure accumulator 7 accumulates a certain amount of hydraulic oil until the pressure is released and then output to drive the generator 11 to work.

[0040] In this embodiment, a low-pressure accumulator 14 is connected to 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 hydraulic oil flowing out of the low-pressure side of the hydraulic motor 10 .

[0041] A second electromagnetic shut-off valve 8.2 is provided between the low-pressure accumulator 14 and the hydraulic circuit.

[0042] 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 to unload the device in case of severe sea conditions, before deployment or during withdrawal, and the entire system does not generate electricity.

[0043] In this embodiment, an electro-hydraulic proportional overflow speed regulating 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 regulating valve 9 is used to adjust the flow rate of the impact hydraulic motor. This valve is particularly useful when the flow rate needs to be varied during onshore and offshore testing to compare and analyze power generation. It can also serve as a control target for power maximization tracking.

[0044] A second flow meter 4.2 and a third pressure gauge 5.3 are provided between the electro-hydraulic proportional overflow speed regulating valve 9 and the input end of the hydraulic motor. After flow regulation, 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.

[0045] A fourth pressure gauge 5.4 is provided at the output end of the hydraulic motor. This gauge is used to measure the pressure at the rear end of the hydraulic motor 10. The pressure differential that drives the motor is measured using the third and fourth pressure gauges 5.3 and 5.4. Whether the generator achieves rated power generation depends on the pressure differential between the front and rear ends of the motor and the input flow rate.

[0046] In this embodiment, the hydraulic circuit is equipped with a second fine oil filter 20 located behind the output end of the hydraulic motor 10. This filter filters the hydraulic oil output by the hydraulic motor 10, the safety valve 13, and the second relief valve 17.2. The filtered hydraulic oil flows through the second solenoid shut-off valve 8.2 into the low-pressure accumulator 14, connects to the output end of the first relief valve 17.1, and finally returns to the hydraulic cylinder through the rectifying valve block 3.

[0047] 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 .

[0048] After working for a period of time, when the oil temperature in the system rises and pollutants such as grinding increase, the high-temperature oil or contaminated oil in the closed hydraulic circuit is replaced by starting the oil replenishment module 16 and the flushing valve 18 to cool the hydraulic oil in the hydraulic circuit and clean the grinding and other pollutants in the hydraulic circuit.

[0049] In this invention, when waves act on an energy-capturing float, the float converts wave energy into its own kinetic energy, thereby driving the movement of the connected hydraulic cylinders. The hydraulic oil output from multiple hydraulic cylinders is then combined and passed through a two-position, three-way reversing valve 6. At the flow rate set by an electro-hydraulic proportional relief valve 9, the hydraulic oil is ultimately fed into a hydraulic motor 10, which drives a generator 11 to generate electricity.

[0050] When the opening of the electro-hydraulic proportional overflow speed regulating valve 9 is set to 0 by the controller, the hydraulic oil is collected and then passed through the two-position three-way reversing valve 6 to choose whether to flow through the voltage-stabilizing energy storage module 15. Regardless of whether it flows through the voltage-stabilizing energy storage module 15, the power generation mode of the entire system is the energy storage power generation mode, which stores the input hydraulic energy in the high-pressure accumulator 7 until the accumulator 7 reaches the set pressure value. The opening of the electro-hydraulic proportional overflow speed regulating 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 to generate electricity.

[0051] When the electro-hydraulic proportional overflow speed regulating valve 9 can also be set to a normally open state through the controller, and the hydraulic oil passes through the two-position three-way reversing valve 6 but not the voltage-stabilizing energy storage module 15, the power generation mode of the entire system is a continuous power generation mode, and the high-pressure accumulator 7 is used to absorb the fluctuation of hydraulic energy caused by wave changes. When the wave energy increases, the accumulator stores the excess energy, and when the wave energy decreases, the accumulator releases the energy, thereby making 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 regulating valve 9 according to the wave conditions, thereby adjusting the hydraulic oil flow of the drive motor 10 during continuous power generation.

[0052] The energy storage power generation mode can be used when the wave energy is at a low energy flow 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 at a high energy flow density for a long time and the generator can continuously output close to the rated power.

[0053] The two-position, three-way reversing valve 6 is used to regulate whether the system passes through the pressure-stabilizing energy storage module 15. When wave energy is very low and the nitrogen pressure in the high-pressure accumulator 7 is much higher than the hydraulic oil input pressure, the hydraulic cylinder's thrust cannot push the rear high-pressure accumulator, causing the hydraulic cylinder to "lock," and hydraulic oil cannot accumulate in the high-pressure accumulator 7. In this case, the pressure-stabilizing energy storage module 15 can amplify the wave energy under the action of micro-amplitude waves, and then slowly accumulate the wave energy in the accumulator until the accumulator reaches the pressure required for power generation. The selection of the pressure-stabilizing energy storage module 15 allows the entire system's power generation modes to be further subdivided into four types: an energy storage and power generation mode using the over-pressure-stabilizing energy storage module, a continuous power generation mode using the over-pressure-stabilizing energy storage module, an energy storage and power generation mode using the over-pressure-stabilizing energy storage module, and a continuous power generation mode using the over-pressure-stabilizing energy storage module. The continuous power generation mode using the over-pressure-stabilizing energy storage module 15 has significant energy dissipation, and is therefore not considered in this system under actual sea conditions.

[0054] Furthermore, in extremely severe sea conditions, such as typhoons and tsunamis, the device structure will be subjected to extremely large wave forces. At this time, the accumulated pressure of the hydraulic oil will exceed the system's operating pressure, and the generator 11 will be in an overloaded operating state. In such sea conditions, the device structure and the entire hydraulic transmission system will face severe challenges. Therefore, the hydraulic system does not generate electricity in such sea conditions to prevent damage to the device structure and system caused by severe sea conditions. This mode is called unloading mode. In this case, the electro-hydraulic proportional overflow speed control valve 9 is set to zero by the controller, while the safety valve 13 is normally open.

[0055] 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 accessing the emergency system. The electromagnetic reversing valve 2 is closed, and the emergency interface 21 is accessed through the external emergency system to control the left and right movement of the hydraulic cylinder to achieve the lifting or lowering of the energy capture float.

[0056] 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 to connect the oil ports of more hydraulic cylinders, thereby realizing the power generation of multiple hydraulic cylinders in the system.

[0057] The main features of the present invention are as follows:

[0058] (1) The hydraulic cylinder in the hydraulic system is of single-rod double-acting type, which can perform double-stroke work and fully capture wave energy. The hydraulic system can collect the energy converted by multiple hydraulic cylinders, realizing the transmission and conversion of wave energy captured by the multi-floating body and multi-degree-of-freedom device. The high and low pressure sides of the system are respectively provided with collection input and output interfaces, which makes the system highly scalable and can realize the distributed array networking of the device.

[0059] (2) The hydraulic PTO system is a closed loop system that can effectively utilize the hydraulic oil flowing out of the low-pressure side of the motor. Compared with the open loop, the hydraulic oil output from the low-pressure side of the motor no longer flows back to the oil 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.

[0060] (3) This hydraulic PTO system can adjust the power generation mode to suit the wave conditions. When the wave conditions are good, it is in continuous power generation mode, and the high-pressure accumulator plays the role of "cutting the front and filling the valley"; when the wave conditions are normal, it is in energy storage power generation mode, accumulating energy to a certain pressure and then releasing it for power generation. Even if the waves are weak, such as microwaves, the system can still store wave energy at low energy flow density in the accumulator for power generation. This hydraulic PTO system has multiple power generation modes, which broadens the wave capture bandwidth.

[0061] (4) The flushing valve 18 and the oil replenishing module 16 in the system can replace the hydraulic oil in the system, which has the functions of cooling and cleaning dirt.

[0062] like Figures 1 to 3 As shown, the present invention also provides a control method for a wave energy power generation hydraulic system, comprising:

[0063] Obtaining operating status data of the wave energy generation hydraulic system;

[0064] changing the operating mode of the wave energy power generation hydraulic system according to the operating status data;

[0065] Specifically:

[0066] When the pressure P of the first pressure gauge 5.1 5.1 Not greater than the charging pressure P of the high-pressure accumulator 7 M1 When the hydraulic oil flows through the pressure stabilizing energy storage module, the system is in the energy storage and power generation mode of the over-pressure stabilizing energy storage module 15, and the energy storage reaches the release pressure P of the high-pressure accumulator 7. S1 Post-release power generation;

[0067] When the pressure P of the first pressure gauge 5.1 5.1 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 When the release pressure of the high-pressure accumulator 7 is twice as high as P M2 , the system is in the energy storage and power generation mode of the voltage-stabilizing energy storage module 15;

[0068] When the pressure P of the first pressure gauge 5.1 5.1 Greater than the hydraulic motor's limit working pressure P M3 When , the system is in unloading mode;

[0069] When P M2 <P 5.1 <P M3 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 15.

[0070] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equalization change and modification made to the above embodiment by any technician familiar with the field without departing from the content of the technical solution of the present invention based on the technical essence of the present invention shall fall within the scope of 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 hydraulic motor, a generator, a flushing valve and at least one hydraulic cylinder in communication with each other. 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. 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 provided between the output end of the pressure-stabilizing energy storage module and the input end of the high-pressure accumulator.

2. The wave energy power generation hydraulic system according to claim 1, characterized in that: The closed hydraulic circuit is further provided with an oil replenishment module, which is connected to the hydraulic circuit via 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, and a first oil tank and a second oil tank. The first oil tank is connected to the first oil replenishment check valve via the oil replenishment overflow valve, and the second oil tank is connected to the second oil replenishment check valve via the oil replenishment pump. A first fine oil filter is provided between the second oil replenishment check valve and the oil replenishment pump. 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 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.

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

5. The wave energy power generation hydraulic system according to claim 1, characterized in that: An electro-hydraulic proportional overflow speed regulating valve is provided 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: The hydraulic circuit is provided with a second fine oil filter behind the output end of the hydraulic motor.

7. 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 provided between the flushing oil tank and the flushing valve.

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

9. A control method based on the wave energy power generation hydraulic system according to claim 1, characterized in that: include: Obtaining operating status data of the wave energy generation hydraulic system; changing the operating mode of the wave energy power generation hydraulic system according to the operating status data; 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 pressure stabilizing energy storage module, the system is in the energy storage and power generation mode of the pressure 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 high-pressure accumulator is twice as high as P M2 , the system is in the energy storage and power generation mode without using the voltage stabilizing energy storage module; When the pressure P of the first pressure gauge 5.1 Greater than the hydraulic motor's limit working pressure P M3 When , the system is in unloading mode; When P M2 <P 5.1 <P M3 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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