Double-rotary valve core rectification type wave energy power generation hydraulic PTO system and control method

Abstract

The application discloses a kind of double rotary valve core rectification type wave energy power generation hydraulic PTO systems and control method.Liquid pressure PTO system's single out rod hydraulic cylinder is connected double rotary valve core rectification module, high pressure oil circuit part, power generation module, low pressure oil circuit part after being connected single out rod hydraulic cylinder again;Displacement sensor is installed on the piston rod of single out rod hydraulic cylinder and is connected mechanical floater, and mechanical floater floats on water surface.The method comprises: the system is placed in wave, and the mechanical floater of the system reciprocates under wave and drives piston rod movement, and finally the electric energy is exported by generator.The application is smoothly and efficiently rectified by double rotary valve core rectification module, and the constant speed of generator and output voltage are realized, the impact on system main oil circuit is reduced, so that it is more stable and easy to control, energy loss is reduced, and the energy capture efficiency of system is improved;Meanwhile, piston rod can smoothly break through dead zone, effectively prolong the system working time, and further improve the system power generation efficiency.

Description

Technical Field

[0001] This invention relates to a hydraulic PTO system, specifically to a dual rotary valve core rectifier wave energy power generation hydraulic PTO system and its control method. Background Technology

[0002] Wave energy is a type of ocean energy and a renewable, clean energy source. Developing and utilizing ocean wave energy is of great significance for sustainable development.

[0003] The Power Take-Off System (PTO) is a crucial component of wave energy conversion devices. Hydraulic PTO systems offer advantages such as high power density, high low-frequency torque, self-lubrication, and ease of automation control, while effectively preventing overload, making them the most widely used. Currently, most hydraulic PTO systems typically consist of a single-rod hydraulic cylinder, a one-way valve rectifier module, high and low-pressure accumulators, a hydraulic motor, and a generator. The basic principle is that a wave-driven mechanical float drives the hydraulic cylinder piston rod in reciprocating motion. The one-way valve rectifies the flow of oil in the main oil circuit, causing it to flow in one direction. The hydraulic motor converts the hydraulic energy of the unidirectionally flowing oil into rotational mechanical energy, and the generator then converts this rotational mechanical energy into electrical energy for output.

[0004] However, current one-way valve rectifier hydraulic PTO systems have some problems. Because single-rod hydraulic cylinders are shorter than double-rod hydraulic cylinders and are suitable for long strokes, most current hydraulic PTO systems generally use single-rod hydraulic cylinders as the actuator. Considering that single-rod hydraulic cylinders are asymmetrical structures while one-way valves are symmetrical structures, there is a difference in the dynamic characteristics of movement in the two directions. If this difference is not effectively compensated, it will cause some impact, affecting the stability of the hydraulic PTO system, and will also result in a loss of captured energy, reducing the energy capture efficiency of the hydraulic PTO system. Simultaneously, when the piston speed drops to zero instantaneously during system startup or reverse movement, if the wave force does not reach a certain threshold, the oil pressure in the hydraulic cylinder is difficult to easily overcome the back pressure of the one-way valve and the friction of the hydraulic cylinder itself. Therefore, existing hydraulic PTO systems are prone to getting stuck in a dead zone when the hydraulic cylinder piston speed is zero, thus reducing the working time of the hydraulic PTO and affecting power generation efficiency. Summary of the Invention

[0005] To address the problems existing in the background technology, the present invention provides a dual-rotary valve core rectifier wave energy power generation hydraulic PTO system and control method. The novel rectifier module composed of dual rotary valve cores smoothly and efficiently rectifies the oil in the main oil circuit, making it flow in one direction, thereby reducing the initial pressure impact and enhancing the stability of the system. At the same time, it effectively avoids the system from falling into the dead zone and improves the power generation efficiency.

[0006] The technical solution adopted in this invention is:

[0007] I. A dual-rotary-valve-core rectifier wave energy generation hydraulic PTO system:

[0008] The hydraulic PTO system includes a single-rod hydraulic cylinder, a dual-rotary valve core rectifier module, a high-pressure oil circuit, a low-pressure oil circuit, a generator module, and a controller. The inlet and outlet ports of the rod chamber of the single-rod hydraulic cylinder are sequentially connected to the dual-rotary valve core rectifier module, the high-pressure oil circuit, the generator module, and the low-pressure oil circuit, and then connected to the inlet and outlet ports of the rodless chamber of the single-rod hydraulic cylinder via the dual-rotary valve core rectifier module. The generator module is electrically connected to external electrical equipment. A displacement sensor is installed on the piston rod in the rod chamber of the single-rod hydraulic cylinder, and the extended end of the piston rod is connected to a mechanical float, which floats on the water surface. The controller is electrically connected to the displacement sensor, the dual-rotary valve core rectifier module, the high-pressure oil circuit, and the low-pressure oil circuit.

[0009] The mechanical float oscillates up and down continuously with the random rise and fall of the waves, which in turn drives the piston rod of the single-rod hydraulic cylinder to reciprocate. The displacement sensor acquires information such as the piston rod's speed and acceleration and transmits it to the controller.

[0010] The high-pressure oil circuit, along the hydraulic oil transmission direction in the hydraulic PTO system, includes a first shut-off valve, a first flow meter, a high-pressure accumulator module, an electro-hydraulic proportional relief speed control valve, and a second flow meter connected in sequence. The input end of the first shut-off valve is connected to a dual rotary valve core rectifier module, and the output end of the second flow meter is connected to the input end of a power generation module. A second pressure sensor is connected between the second flow meter and the power generation module. The low-pressure oil circuit, along the hydraulic oil transmission direction in the hydraulic PTO system, includes a hydraulic oil contamination monitoring module, a low-pressure accumulator module, and a second shut-off valve connected in sequence. The input end of the hydraulic oil contamination monitoring module is connected to the output end of the power generation module, and the output end of the second shut-off valve is connected to the dual rotary valve core rectifier module. A third pressure sensor is connected between the power generation module and the hydraulic oil contamination monitoring module. The first flow meter, the high-pressure accumulator module, the electro-hydraulic proportional relief speed control valve, the second flow meter, the second pressure sensor, the third pressure sensor, the hydraulic oil contamination monitoring module, and the low-pressure accumulator module are all electrically connected to the controller.

[0011] The hydraulic PTO system further includes a first pressure regulating oil circuit, an unloading oil circuit, and a second pressure regulating oil circuit. The input end of the first pressure regulating oil circuit is connected between the output end of the first shut-off valve and the input end of the first flow meter. The output end of the first pressure regulating oil circuit is connected between the input end of the low-pressure accumulator and the output end of the hydraulic oil contamination monitoring module. A safety valve is provided on the first pressure regulating oil circuit, and hydraulic plugs are respectively provided on the process holes at both ends of the safety valve. The input ends of the unloading oil circuit and the second pressure regulating oil circuit are sequentially connected between the input end of the high-pressure accumulator module and the input end of the electro-hydraulic proportional relief speed control valve. The output ends of the second pressure regulating oil circuit and the unloading oil circuit are sequentially connected between the output end of the power generation module and the input end of the hydraulic oil contamination monitoring module. A third solenoid valve and a proportional relief valve are respectively provided on the unloading oil circuit and the second pressure regulating oil circuit. The third solenoid valve and the proportional relief valve are both electrically connected to the controller.

[0012] The high-pressure and low-pressure oil circuits constitute the main oil circuit of the system, and this circuit is a closed circuit, allowing the oil to circulate freely after filling. The first pressure regulating circuit sets the maximum oil pressure of the entire hydraulic PTO system, providing safety protection. When the system pressure exceeds the set value, the safety valve opens, unloading the oil pressure in the hydraulic PTO system to prevent accidents caused by excessive pressure. The unloading circuit prevents hydraulic oil from entering the hydraulic motor of the generator module before the high-pressure accumulator in the high-pressure accumulator module reaches a certain pressure, thus preventing the hydraulic PTO system from performing useless work and achieving intermittent and stable power generation. The second pressure regulating circuit sets the hydraulic motor of the generator module to operate at the maximum oil pressure. When the operating pressure exceeds the set value, the proportional relief valve opens, unloading the oil pressure in the hydraulic PTO system to prevent damage to the hydraulic motor due to excessive pressure.

[0013] The dual rotary valve core rectifier module includes a first rotary motor, a first rotary valve core, a second rotary motor, and a second rotary valve core. The output shafts of the first and second rotary motors are respectively connected to the first and second rotary valve cores. Each of the first and second rotary valve cores includes three working positions. The second working position of the first rotary valve core is between the first and third working positions. The first working position of the first rotary valve core is close to the first rotary motor, and the second working position of the second rotary valve core is between the first and third working positions, with the first working position of the second rotary valve core close to the second rotary motor. Both the first and second working positions of the first and second rotary valve cores are closed, meaning their oil ports are closed and not connected to any oil circuit, used for system pressure maintenance. Each of the first and third working positions of the first and second rotary valve cores has an inlet and outlet oil port. The inlet and outlet oil ports of the first working positions of both the first and second rotary valve cores are connected to the input end of the first shut-off valve in the high-pressure oil circuit section, and the inlet and outlet oil ports of the third working positions of both the first and second rotary valve cores are connected to the output end of the second shut-off valve in the low-pressure oil circuit section.

[0014] When the piston rod of the single-rod hydraulic cylinder moves upward, the first rotary valve core is in the first working position, and the second rotary valve core is in the third working position. The high-pressure oil in the rod chamber of the single-rod hydraulic cylinder is input to the high-pressure oil circuit through the inlet / outlet of the first rotary valve core at the first working position, and the low-pressure oil in the low-pressure oil circuit flows into the rodless chamber of the single-rod hydraulic cylinder through the third working position of the second rotary valve core. When the piston rod of the single-rod hydraulic cylinder moves downward, the first rotary valve core is in the third working position, and the second rotary valve core is in the first working position. The high-pressure oil in the rodless chamber of the single-rod hydraulic cylinder is input to the high-pressure oil circuit through the inlet / outlet of the second rotary valve core at the first working position, and the low-pressure oil in the low-pressure oil circuit flows into the rod chamber of the single-rod hydraulic cylinder through the third working position of the first rotary valve core. Both the first and second rotary motors are electrically connected to the controller.

[0015] The high-pressure accumulator module includes a first solenoid valve, a high-pressure accumulator, and a first pressure sensor. The input end of the first solenoid valve is connected between the output end of the first flow meter and the input end of the third solenoid valve in the unloading oil circuit. The output end of the first solenoid valve is connected to the high-pressure accumulator. The first pressure sensor is connected between the first solenoid valve and the high-pressure accumulator. The low-pressure accumulator module includes a second solenoid valve and a low-pressure accumulator. The input end of the second solenoid valve is connected between the input end of the second shut-off valve and the output end of the safety valve in the first pressure regulating oil circuit. The output end of the second solenoid valve is connected to the low-pressure accumulator. The first solenoid valve, the second solenoid valve, and the first pressure sensor are all electrically connected to the controller.

[0016] The hydraulic fluid contamination monitoring module includes a cooler, two filters, two pressure test connectors, a first check valve, a second check valve, and an online contamination monitor. The two pressure test connectors are connected between the output end of the safety valve in the first pressure regulating circuit and the output end of the third solenoid valve in the unloading circuit. The two pressure test connectors are sequentially connected to the two filters and the cooler along the hydraulic oil transmission direction in the hydraulic PTO system. The first check valve and the second check valve are also connected between the two pressure test connectors. The input and output ends of the first check valve are respectively connected to the output and input ends of the second check valve. The conduction direction of the first check valve is the same as the hydraulic oil transmission direction in the hydraulic PTO system, and the conduction direction of the second check valve is opposite to the hydraulic oil transmission direction in the hydraulic PTO system. The online contamination monitor is also connected between the two pressure test connectors. The online contamination monitor is electrically connected to the controller.

[0017] The filter and two coolers serve the functions of oil filtration and cooling, respectively. Due to the complexity of the marine environment, the cleanliness requirements for the oil are higher, so two filters are set to improve the oil filtration accuracy. The online contamination monitor is used to monitor the oil contamination. The first check valve has a clockwise unidirectional flow direction, but there is a certain back pressure. Under normal operation, it does not flow. When the filter is blocked, the back pressure is broken to avoid excessive pressure and damage. Furthermore, a second check valve is connected to both ends of the first check valve, with a counterclockwise unidirectional flow direction, in order to equalize the pressure and prevent cavitation.

[0018] The power generation module includes a third check valve, a hydraulic motor, and a generator. The input and output ends of the hydraulic motor are respectively connected between the output end of the second flow meter and the output end of the proportional relief valve of the second pressure regulating oil circuit. The input and output ends of the hydraulic motor are respectively connected between the input and output ends of the third check valve. The rotating shaft of the hydraulic motor is connected to the generator, and the generator is electrically connected to an external power supply device. The third check valve is used for oil return replenishment to avoid cavitation. The second pressure sensor is connected between the output end of the second flow meter and the input end of the hydraulic motor, and the third pressure sensor is connected between the output end of the hydraulic motor and the output end of the proportional relief valve of the second pressure regulating oil circuit.

[0019] The dual rotary valve core rectifier module rectifies the bidirectional flow of oil in the high-pressure oil circuit and the low-pressure oil circuit, making it flow in one direction. The hydraulic motor of the generator module converts the hydraulic energy of the unidirectional flow of oil into rotational mechanical energy, and the generator of the generator module then converts the rotational mechanical energy into electrical energy for output.

[0020] During the power generation process of the hydraulic PTO system, the first and second shut-off valves need to be manually or electrically opened before the system is working normally and remain open, only closing during system alarms or shutdown maintenance. The first flow meter is used to detect the flow at the high-pressure output end of the dual rotary valve core rectifier module; the second flow meter is used to detect the flow at the input end of the hydraulic motor; the second pressure sensor is used to detect the pressure at the input end of the hydraulic motor; the high-pressure accumulator's function is to store energy, stabilize pressure, and smooth peak and valley loads to ensure stable system operation. When the first pressure sensor of the high-pressure accumulator module detects that the set high pressure has been reached, the first solenoid valve opens to quickly release the oil pressure of the high-pressure accumulator into the high-pressure oil circuit. The electro-hydraulic proportional overflow speed control valve adjusts the valve opening in real time according to the detected pressure and flow to control the flow into the hydraulic motor, thereby achieving a relatively constant generator speed and output voltage; the third pressure sensor is used to detect the pressure at the output end of the hydraulic motor; the low-pressure accumulator's function is to absorb the return oil pressure and eliminate discharge pressure fluctuations. The second solenoid valve of the low-pressure accumulator module remains open during normal operation and closes during system alarms or shutdown maintenance.

[0021] II. A control method for a dual-rotary-valve-core rectifier wave energy generation hydraulic PTO system:

[0022] Steps: Initialize the sensor parameters of the first pressure sensor, second pressure sensor, and third pressure sensor of the hydraulic PTO system and the control parameters of the controller. Start the hydraulic PTO system under the preset pressure parameters of the hydraulic PTO system. Open the first shut-off valve, second shut-off valve, first solenoid valve, second solenoid valve, and electro-hydraulic proportional relief speed control valve in sequence, and keep them open when the hydraulic PTO system is working normally.

[0023] Steps: Place one or more hydraulic PTO systems in the waves. For each hydraulic PTO system, the mechanical float connected to the extended end of the piston rod of the single-rod hydraulic cylinder of the hydraulic PTO system reciprocates under the action of the waves, driving the piston rod of the single-rod hydraulic cylinder to reciprocate. The dual rotary valve core rectifier module rectifies the bidirectional flow of oil in the high-pressure oil circuit and the low-pressure oil circuit, making it flow in one direction. Finally, the hydraulic energy of the unidirectional flow of oil is converted into rotational mechanical energy by the hydraulic motor, and then the rotational mechanical energy is converted into electrical energy by the generator and output to the external electrical equipment.

[0024] In the aforementioned steps, the preset pressure parameters of the hydraulic PTO system include the system pressure of the safety valve, the working pressure of the proportional relief valve, and the high-pressure arrival pressure of the first pressure sensor. The system pressure of the safety valve is slightly higher than the working pressure of the proportional relief valve. When the hydraulic PTO system is operating normally, the safety valve, the third solenoid valve, and the proportional relief valve are all closed. When the hydraulic PTO system is not operating normally: when the controller receives a system pressure detected by the pressure sensor exceeding the system pressure of the safety valve, the controller issues an alarm, indicating that the hydraulic PTO system is in an abnormal operating condition. At this time, the safety valve opens to unload the oil pressure in the hydraulic PTO system, thereby ensuring that the system does not experience an accident due to excessive pressure. When the system pressure does not exceed the system pressure of the safety valve, the safety valve closes. When the controller receives... When the hydraulic motor's operating pressure detected by the pressure sensor exceeds the proportional relief valve's operating pressure, the controller issues an alarm, indicating that the hydraulic PTO system is in an abnormal operating condition. At this time, the proportional relief valve opens to unload the oil pressure in the hydraulic PTO system, thus ensuring that the hydraulic motor is not damaged due to excessive pressure. When the hydraulic motor's operating pressure does not exceed the proportional relief valve's operating pressure, the proportional relief valve closes. When the controller receives the high-pressure accumulator's operating pressure detected by the first pressure sensor, exceeding the high-pressure threshold of the first pressure sensor, the controller issues an alarm, indicating that the hydraulic PTO system is in an abnormal operating condition. At this time, the first solenoid valve closes. When the high-pressure accumulator's operating pressure does not exceed the high-pressure threshold of the first pressure sensor, the first solenoid valve opens.

[0025] The abnormal operating conditions of the hydraulic PTO system also include: the controller receiving alarms when the output and input flow rates of the hydraulic motor detected by the first and second flow meters are outside the preset flow range; the controller receiving alarms when the input and output pressures of the hydraulic motor detected by the second and third pressure sensors are outside the preset pressure range; the controller receiving alarms when the hydraulic PTO system is contaminated according to feedback from the online contamination monitor; and the hydraulic PTO system encountering short-term extreme waves. In these situations, the controller will perform standby maintenance or shutdown maintenance on the hydraulic PTO system. Specifically, the first and second rotary valves of the dual rotary valve rectifier module will be simultaneously set to their respective second operating states. In the operating position, the system is in a pressure-holding state. The piston rod of the single-rod hydraulic cylinder stops reciprocating. The single-rod hydraulic cylinder oscillates back and forth with the mechanical float, no longer performing work to protect the system and prevent damage to the device. The system remains running at this time so that it can quickly resume operation after extreme waves or standby maintenance. When the hydraulic PTO system is shut down for maintenance, the first shut-off valve, the second shut-off valve, the first solenoid valve, and the second solenoid valve must be closed simultaneously to disconnect the main oil circuit of the high-pressure oil circuit and the low-pressure oil circuit of the hydraulic PTO system from the single-rod hydraulic cylinder. Then, the hydraulic PTO system is subjected to standby maintenance or shutdown maintenance. After the system maintenance is completed, the alarm signal is cleared, and the hydraulic PTO system returns to normal operation.

[0026] The hydraulic PTO system is in an abnormal operating condition, which also includes: the controller receiving a zero instantaneous displacement of the piston rod of the single-rod hydraulic cylinder detected by displacement sensor b, meaning that the instantaneous velocity of the piston rod drops to zero when the wave force is not large enough. At this point, the system is prone to getting stuck in a dead zone. The controller then sets the first and second rotary valves of the dual rotary valve rectifier module to their respective third working positions simultaneously, so that both the rod-side and rodless sides of the single-rod hydraulic cylinder are connected to the low-pressure oil circuit. In this state, the hydraulic PTO system does not perform work, allowing the piston rod of the single-rod hydraulic cylinder to gain a certain initial velocity even under very small wave force conditions, thus successfully overcoming the dead zone. This continues until the controller receives a non-zero instantaneous displacement of the piston rod of the single-rod hydraulic cylinder detected by displacement sensor b. Then, the controller adjusts the first and second rotary valves of the dual rotary valve rectifier module back to their normal operating positions, allowing the hydraulic PTO system to continue performing work and outputting electrical energy. Although this causes the system to temporarily stop working, it effectively avoids the system getting stuck in a dead zone, extending the total operating time of the system and thus improving the system's power generation efficiency.

[0027] In the aforementioned steps, when the piston rod of the single-rod hydraulic cylinder reciprocates, it converts wave energy into hydraulic energy. When the piston rod of the single-rod hydraulic cylinder moves upward, the controller controls the first rotary motor of the dual rotary valve core rectifier module to drive the first rotary valve core to the first working position, and controls the second rotary motor to drive the second rotary valve core to the third working position. The high-pressure oil in the rod chamber of the single-rod hydraulic cylinder is forced out and input to the high-pressure oil circuit through the inlet and outlet ports of the first rotary valve core of the dual rotary valve core rectifier module at the first working position, and then input to the power generation module. The power generation module converts the high-pressure oil into low-pressure oil and inputs it to the low-pressure oil circuit. The low-pressure oil circuit then inputs the low-pressure oil through the inlet and outlet ports of the second rotary valve core of the dual rotary valve core rectifier module at the third working position. The oil outlet is fed into the rodless chamber of the single-rod hydraulic cylinder. When the piston rod of the single-rod hydraulic cylinder moves downward, the controller controls the first rotary motor of the dual rotary valve core rectifier module to drive the first rotary valve core to the third working position, and controls the second rotary motor to drive the second rotary valve core to the first working position. The high-pressure oil in the rodless chamber of the single-rod hydraulic cylinder is forced out and fed into the high-pressure oil circuit through the inlet and outlet ports of the second rotary valve core of the dual rotary valve core rectifier module at the first working position. Then it is fed into the power generation module. The power generation module converts the high-pressure oil into low-pressure oil and feeds it into the low-pressure oil circuit. The low-pressure oil circuit feeds the low-pressure oil into the rod chamber of the single-rod hydraulic cylinder through the inlet and outlet ports of the first rotary valve core of the dual rotary valve core rectifier module at the third working position.

[0028] The controller adjusts the opening of the first and second rotary valve cores by controlling the rotation angles of the first and second rotary motors of the dual rotary valve core rectifier module. Specifically, based on the area ratio of the rod chamber to the rodless chamber of the single-rod hydraulic cylinder, the controller applies control signals to the first and second rotary motors, making the ratio of the valve opening of the first rotary valve core to the valve opening of the second rotary valve core equal to the area ratio of the rod chamber to the rodless chamber of the single-rod hydraulic cylinder. This control addresses the issue of differences in dynamic characteristics in two directions caused by the asymmetrical structure of the single-rod hydraulic cylinder. It eliminates the hydraulic pressure fluctuations caused by the asymmetrical structure during the reciprocating motion of the piston rod of the single-rod hydraulic cylinder. On the one hand, it reduces the initial impact on the main oil circuit of the system, making the system more stable and easier to control. On the other hand, the good matching between the dual rotary valve core rectifier module and the single-rod hydraulic cylinder reduces energy loss to a certain extent and improves the energy capture efficiency of the system. The valve opening ratio of the two rotary valve cores of the dual rotary valve core rectifier module can also be independently adjusted according to the current system flow and pressure to dynamically match the changes in wave force, achieve efficient and stable rectification, and further improve the system's energy capture efficiency.

[0029] The adjustment of the first and second rotary valve cores is independent and there is no coupling relationship. The dual rotary valve core rectifier module ensures that regardless of whether the single-rod hydraulic cylinder is in its stroke or return phase, the hydraulic oil from the single-rod hydraulic cylinder enters the high-pressure oil circuit of the hydraulic system and flows back to the single-rod hydraulic cylinder from the low-pressure oil circuit. The dual rotary valve core rectifier module and the electro-hydraulic proportional relief speed control valve control the output flow and pressure of the single-rod hydraulic cylinder and the input flow and pressure of the hydraulic motor, respectively. The control of the dual rotary valve core rectifier module can achieve smooth and efficient rectification, and the controller's control of the valve opening of the electro-hydraulic proportional relief speed control valve can achieve a relatively constant speed and output voltage of the generator.

[0030] The beneficial effects of this invention are:

[0031] This invention addresses the problem of differing dynamic characteristics in two directions caused by the asymmetrical structure of the single-rod hydraulic cylinder used in most current wave energy power generation hydraulic PTO systems. By using a dual rotary valve core rectifier module, the oil pressure fluctuations caused by the asymmetrical structure during the reciprocating motion of the hydraulic cylinder piston rod are eliminated. This not only reduces the initial impact on the main oil circuit of the system, making the system more stable and easier to control, but also, due to the good matching between the dual rotary valve core rectifier module and the single-rod hydraulic cylinder, reduces energy loss to a certain extent and improves the energy capture efficiency of the system.

[0032] To address the issue of the system easily getting stuck in a dead zone when the hydraulic cylinder piston's instantaneous speed drops to zero during system startup or reverse movement due to insufficient wave force, this invention uses a built-in displacement sensor to detect the current piston's motion state and effectively avoids the system getting stuck in a dead zone by adjusting the dual rotary valve core rectifier module. This extends the total system operating time and improves the system's power generation efficiency. In addition, the valve opening ratio of the two rotary valve cores of the dual rotary valve core rectifier module can be independently adjusted according to the current system flow and pressure to dynamically match changes in wave force, further improving the system's energy capture efficiency. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the hydraulic PTO system of the present invention;

[0034] Figure 2 This is a schematic diagram of the hydraulic PTO system control method of the present invention;

[0035] In the diagram: 1. Single-rod hydraulic cylinder; 1a. Mechanical float; 1b. Displacement sensor; 2. Dual-rotary valve core rectifier module; 2a1. First rotary motor; 2a2. First rotary valve core; 2b1. Second rotary motor; 2b2. Second rotary valve core; 3. Safety valve; 4a. First shut-off valve; 4b. Second shut-off valve; 5a. First solenoid valve; 5b. Second solenoid valve; 5c. Third solenoid valve; 6a. High-voltage accumulator; 6b. Low-voltage accumulator; 7a. First... Pressure sensor, 7b, second pressure sensor, 7c, third pressure sensor, 8a, first flow meter, 8b, second flow meter, 9, hydraulic plug, 10, cooler, 11, filter, 12, pressure test connector, 13a, first check valve, 13b, second check valve, 13c, third check valve, 14, online pollution monitor, 15, proportional relief valve, 16, electro-hydraulic proportional relief speed control valve, 17, hydraulic motor, 18, generator, 19, controller. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] like Figure 1 As shown, the hydraulic PTO system of this invention includes a single-rod hydraulic cylinder 1, a dual-rotary valve core rectifier module 2, a high-pressure oil circuit, a low-pressure oil circuit, a power generation module, and a controller. The inlet and outlet ports of the rod chamber of the single-rod hydraulic cylinder 1 are sequentially connected to the dual-rotary valve core rectifier module 2, the high-pressure oil circuit, the power generation module, and the low-pressure oil circuit, and then connected to the inlet and outlet ports of the rodless chamber of the single-rod hydraulic cylinder 1 via the dual-rotary valve core rectifier module 2. The power generation module is electrically connected to external electrical equipment. A displacement sensor 1b is installed on the piston rod in the rod chamber of the single-rod hydraulic cylinder 1, and the extended end of the piston rod is connected to a mechanical float 1a, which floats on the water surface. The controller is electrically connected to the displacement sensor 1b, the dual-rotary valve core rectifier module 2, the high-pressure oil circuit, and the low-pressure oil circuit. The mechanical float 1a oscillates up and down continuously with the random fluctuations of the waves, thereby driving the piston rod of the single-rod hydraulic cylinder 1 to reciprocate. The displacement sensor 1b acquires information such as the movement speed and acceleration of the piston rod and transmits it to the controller.

[0038] The high-pressure oil circuit, along the hydraulic oil transmission direction in the hydraulic PTO system, includes a first shut-off valve 4a, a first flow meter 8a, a high-pressure accumulator module, an electro-hydraulic proportional relief speed control valve 16, and a second flow meter 8b connected in sequence. The input end of the first shut-off valve 4a is connected to the dual rotary valve core rectifier module 2, and the output end of the second flow meter 8b is connected to the input end of the generator module. A second pressure sensor 7b is connected between the second flow meter 8b and the generator module. The low-pressure oil circuit, along the hydraulic oil transmission direction in the hydraulic PTO system, includes a first shut-off valve 4a, a first flow meter 8a, a high-pressure accumulator module, an electro-hydraulic proportional relief speed control valve 16, and a second flow meter 8b. The hydraulic oil contamination monitoring module, the low-pressure accumulator module, and the second shut-off valve 4b are connected. The input end of the hydraulic oil contamination monitoring module is connected to the output end of the power generation module, and the output end of the second shut-off valve 4b is connected to the double rotary valve core rectifier module 2. A third pressure sensor 7c is connected between the power generation module and the hydraulic oil contamination monitoring module. The first flow meter 8a, the high-pressure accumulator module, the electro-hydraulic proportional overflow speed control valve 16, the second flow meter 8b, the second pressure sensor 7b, the third pressure sensor 7c, the hydraulic oil contamination monitoring module, and the low-pressure accumulator module are all electrically connected to the controller.

[0039] The hydraulic PTO system also includes a first pressure regulating oil circuit, an unloading oil circuit, and a second pressure regulating oil circuit. The input end of the first pressure regulating oil circuit is connected between the output end of the first shut-off valve 4a and the input end of the first flow meter 8a. The output end of the first pressure regulating oil circuit is connected between the input end of the low-pressure accumulator and the output end of the hydraulic oil contamination monitoring module. A safety valve 3 is provided on the first pressure regulating oil circuit, and hydraulic plugs 9 are respectively provided on the process holes at both ends of the safety valve 3. The input ends of the unloading oil circuit and the second pressure regulating oil circuit are sequentially connected between the input end of the high-pressure accumulator module and the input end of the electro-hydraulic proportional overflow speed control valve 16. The output ends of the second pressure regulating oil circuit and the unloading oil circuit are sequentially connected between the output end of the power generation module and the input end of the hydraulic oil contamination monitoring module. A third solenoid valve 5c and a proportional overflow valve 15 are respectively provided on the unloading oil circuit and the second pressure regulating oil circuit. The third solenoid valve 5c and the proportional overflow valve 15 are both electrically connected to the controller 19.

[0040] The high-pressure oil circuit and the low-pressure oil circuit constitute the main oil circuit of the system. This oil circuit is a closed circuit, in which the oil circulates after being filled. The first pressure regulating oil circuit is used to set the maximum oil pressure of the entire hydraulic PTO system, which plays a safety protection role in the hydraulic PTO system. When the system pressure exceeds the set value, the safety valve 3 opens to unload the oil pressure in the hydraulic PTO system, thereby ensuring that the hydraulic PTO system does not have an accident due to excessive pressure. The unloading oil circuit is used to prevent hydraulic oil from entering the hydraulic motor 17 of the generator module before the high-pressure accumulator 6a of the high-pressure accumulator module reaches a certain pressure, which would cause the hydraulic PTO system to do useless work and achieve intermittent and stable power generation. The second pressure regulating oil circuit is used to set the hydraulic motor 17 of the generator module to operate at the maximum oil pressure. When the operating pressure exceeds the set value, the proportional relief valve 15 opens to unload the oil pressure in the hydraulic PTO system, thereby ensuring that the hydraulic motor 17 is not damaged due to excessive pressure.

[0041] The dual rotary valve core rectifier module 2 includes a first rotary motor 2a1, a first rotary valve core 2a2, a second rotary motor 2b1, and a second rotary valve core 2b2. The output shafts of the first rotary motor 2a1 and the second rotary motor 2b1 are respectively connected to the first rotary valve core 2a2 and the second rotary valve core 2b2. Both the first rotary valve core 2a2 and the second rotary valve core 2b2 include three working positions. The second working position of the first rotary valve core 2a2 is between the first working position and the third working position, and the first working position of the first rotary valve core 2a2 is close to the first rotary motor 2a1. The second working position of the second rotary valve core 2b2 is between the first working position and the third working position. The first working position is close to the second rotary motor 2b1; the second working positions of the first rotary valve core 2a2 and the second rotary valve core 2b2 are both closed, that is, the oil ports of the second working positions are both closed and not connected to any oil circuit, which is used for system pressure maintenance; the first working position and the third working position of the first rotary valve core 2a2 and the second rotary valve core 2b2 each have an inlet and an outlet oil port, the inlet and outlet oil ports of the first working position of the first rotary valve core 2a2 and the second rotary valve core 2b2 are all connected to the input end of the first shut-off valve 4a of the high-pressure oil circuit section, and the inlet and outlet oil ports of the third working position of the first rotary valve core 2a2 and the second rotary valve core 2b2 are all connected to the output end of the second shut-off valve 4b of the low-pressure oil circuit section.

[0042] When the piston rod of the single-rod hydraulic cylinder 1 moves upward, the first rotary valve core 2a2 is in the first working position and the second rotary valve core 2b2 is in the third working position. The high-pressure oil in the rod chamber of the single-rod hydraulic cylinder 1 is input to the high-pressure oil circuit through the inlet / outlet of the first rotary valve core 2a2 at the first working position, and the low-pressure oil in the low-pressure oil circuit flows into the rodless chamber of the single-rod hydraulic cylinder 1 through the third working position of the second rotary valve core 2b2. When the piston rod of the single-rod hydraulic cylinder 1 moves downward, the first rotary valve core 2a2 is in the third working position and the second rotary valve core 2b2 is in the first working position. The high-pressure oil in the rodless chamber of the single-rod hydraulic cylinder 1 is input to the high-pressure oil circuit through the inlet / outlet of the second rotary valve core 2b2 at the first working position, and the low-pressure oil in the low-pressure oil circuit flows into the rod chamber of the single-rod hydraulic cylinder 1 through the third working position of the first rotary valve core 2a2. The first rotary motor 2a1 and the second rotary motor 2b1 are both electrically connected to the controller.

[0043] The high-pressure accumulator module includes a first solenoid valve 5a, a high-pressure accumulator 6a, and a first pressure sensor 7a. The input end of the first solenoid valve 5a is connected between the output end of the first flow meter 8a and the input end of the third solenoid valve 5c in the unloading oil circuit. The output end of the first solenoid valve 5a is connected to the high-pressure accumulator 6a. The first pressure sensor 7a is connected between the first solenoid valve 5a and the high-pressure accumulator 6a. The low-pressure accumulator module includes a second solenoid valve 5b and a low-pressure accumulator 6b. The input end of the second solenoid valve 5b is connected between the input end of the second shut-off valve 4b and the output end of the safety valve 3 in the first pressure regulating oil circuit. The output end of the second solenoid valve 5b is connected to the low-pressure accumulator 6b. The first solenoid valve 5a, the second solenoid valve 5b, and the first pressure sensor 7a are all electrically connected to the controller 19.

[0044] The hydraulic fluid contamination monitoring module includes a cooler 10, two filters 11, two pressure test connectors 12, a first check valve 13a, a second check valve 13b, and an online contamination monitor 14. The two pressure test connectors 12 are connected between the output end of the safety valve 3 in the first pressure regulating circuit and the output end of the third solenoid valve 5c in the unloading circuit. The two pressure test connectors 12 are sequentially connected to the two filters 11 and the cooler 10 along the transmission direction of the hydraulic oil in the hydraulic PTO system. The first check valve 13a and the second check valve 13b are also connected between the two pressure test connectors 12. The input and output ends of the first check valve 13a are respectively connected to the output and input ends of the second check valve 13b. The conduction direction of the first check valve 13a is the same as the transmission direction of the hydraulic oil in the hydraulic PTO system, and the conduction direction of the second check valve 13b is opposite to the transmission direction of the hydraulic oil in the hydraulic PTO system. The online contamination monitor 14 is also connected between the two pressure test connectors 12. The online contamination monitor 14 is electrically connected to the controller 19.

[0045] The filter 11 and the two coolers 10 serve the functions of oil filtration and cooling, respectively. Due to the complexity of the marine environment, the cleanliness requirements for the oil are higher. Two filters 11 are set to improve the oil filtration accuracy. The online pollution monitor 14 is used to monitor the oil pollution. The first one-way valve 13a has a clockwise unidirectional flow direction, but there is a certain back pressure. Under normal operation, it does not flow. When the filter 11 is blocked, the back pressure is broken to avoid damage due to excessive pressure. Furthermore, a second one-way valve 13b is connected to both ends of the first one-way valve 13a. The unidirectional flow direction is counterclockwise. The purpose is to equalize the pressure and prevent cavitation.

[0046] The power generation module includes a third check valve 13c, a hydraulic motor 17, and a generator 18. The input and output ends of the hydraulic motor 17 are respectively connected between the output end of the second flow meter 8b and the output end of the proportional relief valve 15 of the second pressure regulating oil circuit. The input and output ends of the hydraulic motor 17 are respectively connected between the input and output ends of the third check valve 13c. The rotating shaft of the hydraulic motor 17 is connected to the generator 18, and the generator 18 is electrically connected to an external power supply device. The third check valve 13c is used for oil return replenishment to avoid cavitation. The second pressure sensor 7b is connected between the output end of the second flow meter 8b and the input end of the hydraulic motor 17, and the third pressure sensor 7c is connected between the output end of the hydraulic motor 17 and the output end of the proportional relief valve 15 of the second pressure regulating oil circuit.

[0047] The dual rotary valve core rectifier module 2 rectifies the bidirectional flow of oil in the high-pressure oil circuit and the low-pressure oil circuit, making it flow in one direction. The hydraulic motor 17 of the generator module converts the hydraulic energy of the unidirectional flow of oil into rotational mechanical energy, and the generator 18 of the generator module then converts the rotational mechanical energy into electrical energy for output.

[0048] During the power generation process of the hydraulic PTO system, the first shut-off valve 4a and the second shut-off valve 4b need to be manually or electrically opened before the system is working normally and remain open, only closing during system alarms or shutdown maintenance; the first flow meter 8a is used to detect the flow at the high-pressure output end of the dual rotary valve core rectifier module 2; the second flow meter 8b is used to detect the flow at the input end of the hydraulic motor 17; the second pressure sensor 7b is used to detect the pressure at the input end of the hydraulic motor 17; the function of the high-pressure accumulator 6a is to store energy, stabilize voltage, and smooth peak and valley loads to ensure stable system operation. When the first pressure sensor 7a of the high-pressure accumulator module detects... After the high pressure is reached, the first solenoid valve 5a is opened to quickly release the oil pressure of the high-pressure accumulator 6a into the high-pressure oil circuit. The electro-hydraulic proportional overflow speed control valve 16 adjusts the valve opening in real time according to the detected pressure and flow to control the flow into the hydraulic motor 17, thereby achieving a relatively constant speed and output voltage of the generator 18. The third pressure sensor 7c is used to detect the pressure at the output end of the hydraulic motor 17. The function of the low-pressure accumulator 6b is to absorb the oil pressure of the return oil and eliminate the fluctuation of the discharge pressure. The second solenoid valve 5b of the low-pressure accumulator module is kept open during normal operation and closed when the system alarms or stops for maintenance.

[0049] The control method of the hydraulic PTO system of the present invention includes the following steps:

[0050] Step 1: Initialize the sensor parameters of the first pressure sensor 7a, the second pressure sensor 7b, and the third pressure sensor 7c of the hydraulic PTO system and the control parameters of the controller 19. Start the hydraulic PTO system under the preset pressure parameters of the hydraulic PTO system, and sequentially open the first shut-off valve 4a, the second shut-off valve 4b, the first solenoid valve 5a, the second solenoid valve 5b, and the electro-hydraulic proportional relief speed control valve 16, and keep them open when the hydraulic PTO system is working normally.

[0051] In step 1, the preset pressure parameters of the hydraulic PTO system include the system pressure of safety valve 3, the working pressure of proportional relief valve 15, and the high-pressure arrival pressure of the first pressure sensor 7a. The system pressure of safety valve 3 is slightly higher than the working pressure of proportional relief valve 15. When the hydraulic PTO system is working normally, safety valve 3, the third solenoid valve 5c, and proportional relief valve 15 are all closed. When the hydraulic PTO system is not working normally: when the controller 19 receives the system pressure detected by pressure sensor 7a exceeding the system pressure of safety valve 3, the controller 19 issues an alarm, indicating that the hydraulic PTO system is in an abnormal working condition. At this time, safety valve 3 is opened to unload the oil pressure in the hydraulic PTO system, thereby ensuring that the system does not have an accident due to excessive pressure. When the system pressure does not exceed the system pressure of safety valve 3, safety valve 3 is closed. When the controller 19 receives the pressure sensor... When the working pressure of the hydraulic motor 17 detected by the device 7b exceeds the working pressure of the proportional relief valve 15, the controller 19 issues an alarm, indicating that the hydraulic PTO system is in an abnormal working condition. At this time, the proportional relief valve 15 is opened to unload the oil pressure in the hydraulic PTO system, thereby ensuring that the hydraulic motor 17 is not damaged due to excessive pressure. When the working pressure of the hydraulic motor 17 does not exceed the working pressure of the proportional relief valve 15, the proportional relief valve 15 is closed. When the controller 19 receives the working pressure of the high-pressure accumulator 6a detected by the first pressure sensor 7a, which exceeds the high pressure arrival pressure of the first pressure sensor 7a, the controller 19 issues an alarm, indicating that the hydraulic PTO system is in an abnormal working condition. At this time, the first solenoid valve 5a is closed. When the working pressure of the high-pressure accumulator 6a does not exceed the high pressure arrival pressure of the first pressure sensor 7a, the first solenoid valve 5a is opened.

[0052] The hydraulic PTO system is in an abnormal operating condition, including when the controller 19 receives signals from the first flow meter 8a and the second flow meter 8b indicating that the output and input flow rates of the hydraulic motor 17 are outside the preset flow range; when the controller 19 receives signals from the second pressure sensor 7b and the third pressure sensor 7c indicating that the input and output pressures of the hydraulic motor 17 are outside the preset pressure range; when the controller 19 receives feedback from the online contamination monitor 14 indicating that the hydraulic oil in the hydraulic PTO system is contaminated; and when the hydraulic PTO system encounters short-term extreme waves, the controller 19 issues an alarm. In these cases, the hydraulic PTO system is put into standby or shutdown maintenance. Specifically, the first rotary valve core 2a2 and the second rotary valve core 2b2 of the dual rotary valve core rectifier module 2 are set to operate simultaneously. At their respective second working positions, the system is in a pressure-holding state. The piston rod of the single-rod hydraulic cylinder 1 stops reciprocating. The single-rod hydraulic cylinder 1 oscillates back and forth with the mechanical float 1a and no longer performs work to protect the system and prevent damage to the device. At this time, the system remains running so that it can quickly resume operation after extreme waves or standby maintenance. When the hydraulic PTO system is shut down for maintenance, the first shut-off valve 4a, the second shut-off valve 4b, the first solenoid valve 5a, and the second solenoid valve 5b must also be closed at the same time to disconnect the main oil circuit of the high-pressure oil circuit and the low-pressure oil circuit of the hydraulic PTO system from the single-rod hydraulic cylinder 1. Then, the hydraulic PTO system is subjected to standby maintenance or shutdown maintenance. When the system maintenance is completed, the alarm signal is cleared, and the hydraulic PTO system returns to normal operation.

[0053] When the hydraulic PTO system is in an abnormal operating condition, the controller 19 receives a zero instantaneous displacement of the piston rod of the single-rod hydraulic cylinder 1 detected by the displacement sensor 1b, meaning that the instantaneous velocity of the piston rod drops to zero when the wave force is not large enough. At this time, the system is prone to getting stuck in the dead zone. In this case, the controller 19 sets the first rotary valve core 2a2 and the second rotary valve core 2b2 of the dual rotary valve core rectifier module 2 to be in their respective third working positions at the same time, so that the rod chamber and the rodless chamber of the single-rod hydraulic cylinder 1 are connected to the low-pressure oil circuit at the same time. At this time, the hydraulic PTO system does not do work, so that the piston rod of the single-rod hydraulic cylinder 1 can obtain a certain initial velocity under extremely small wave force conditions to successfully break through the dead zone. Until the controller 19 receives a non-zero instantaneous displacement of the piston rod of the single-rod hydraulic cylinder 1 detected by the displacement sensor 1b, the controller 19 adjusts the first rotary valve core 2a2 and the second rotary valve core of the dual rotary valve core rectifier module 2 to return to the normal operating position, so that the hydraulic PTO system continues to do work and output electrical energy. Although this causes the system to temporarily stop working, it effectively prevents the system from falling into a dead zone, extends the total operating time of the system, and thus improves the system's power generation efficiency.

[0054] Step 2: Place one or more hydraulic PTO systems in the waves. For each hydraulic PTO system, the mechanical float 1a connected to the extended end of the piston rod of the single-rod hydraulic cylinder 1 of the hydraulic PTO system reciprocates under the action of the waves, driving the piston rod of the single-rod hydraulic cylinder 1 to reciprocate. The dual rotary valve core rectifier module 2 rectifies the bidirectional flow of oil in the high-pressure oil circuit and the low-pressure oil circuit to make it flow in one direction. Finally, the hydraulic energy of the unidirectional flow of oil is converted into rotational mechanical energy by the hydraulic motor 17, and then the rotational mechanical energy is converted into electrical energy by the generator 18 and output to the external electrical equipment.

[0055] In step 2, when the piston rod of the single-rod hydraulic cylinder 1 reciprocates, it converts wave energy into hydraulic energy. When the piston rod of the single-rod hydraulic cylinder 1 moves upward, the controller 19 controls the first rotary motor 2a1 of the dual rotary valve core rectifier module 2 to drive the first rotary valve core 2a2 to the first working position, and controls the second rotary motor 2b1 to drive the second rotary valve core 2b2 to the third working position. The high-pressure oil in the rod chamber of the single-rod hydraulic cylinder 1 is forced out and input to the high-pressure oil circuit through the inlet and outlet ports of the first rotary valve core 2a2 of the dual rotary valve core rectifier module 2 at the first working position, and then inputs to the power generation module. The power generation module converts the high-pressure oil into low-pressure oil and inputs it to the low-pressure oil circuit. The low-pressure oil circuit then inputs the low-pressure oil through the inlet and outlet ports of the second rotary valve core 2b2 of the dual rotary valve core rectifier module 2 at the third working position. The oil is input to the rodless chamber of the single-rod hydraulic cylinder 1. When the piston rod of the single-rod hydraulic cylinder 1 moves downward, the controller 19 controls the first rotary motor 2a1 of the dual rotary valve core rectifier module 2 to drive the first rotary valve core 2a2 to the third working position, and controls the second rotary motor 2b1 to drive the second rotary valve core 2b2 to the first working position. The high-pressure oil in the rodless chamber of the single-rod hydraulic cylinder 1 is forced out and input to the high-pressure oil circuit through the inlet and outlet ports of the second rotary valve core 2b2 of the dual rotary valve core rectifier module 2 at the first working position. Then it is input to the power generation module. The power generation module converts the high-pressure oil into low-pressure oil and inputs it to the low-pressure oil circuit. The low-pressure oil circuit inputs the low-pressure oil to the rod chamber of the single-rod hydraulic cylinder 1 through the inlet and outlet ports of the first rotary valve core 2a2 of the dual rotary valve core rectifier module 2 at the third working position.

[0056] The controller 19 controls the rotation angle of the first rotary motor 2a1 and the second rotary motor 2b1 of the dual rotary valve core rectifier module 2 to adjust the opening degree of the first rotary valve core 2a2 and the second rotary valve core 2b2. Specifically, based on the area ratio of the rod chamber to the rodless chamber of the single-rod hydraulic cylinder 1, the controller applies control signals to the first rotary motor 2a1 and the second rotary motor 2b1, making the ratio of the valve opening degree of the first rotary valve core 2a2 to the valve opening degree of the second rotary valve core 2b2 equal to the area ratio of the rod chamber to the rodless chamber of the single-rod hydraulic cylinder 1. The above control can address the problem of the difference in dynamic characteristics of movement in two directions caused by the asymmetrical structure of the single-rod hydraulic cylinder 1, and eliminate the oil pressure fluctuation caused by the asymmetrical structure when the piston rod of the single-rod hydraulic cylinder 1 reciprocates. On the one hand, it can reduce the impact on the main oil circuit of the system in the early stage, making the system more stable and easier to control. On the other hand, due to the good matching between the dual rotary valve core rectifier module 2 and the single-rod hydraulic cylinder 1, energy loss is reduced to a certain extent, and the energy capture efficiency of the system is improved. The valve opening ratio of the two rotary valve cores of the dual rotary valve core rectifier module 2 can also be independently adjusted according to the current system flow and pressure to dynamically match the changes in wave force, achieve efficient and stable rectification, and further improve the system's energy capture efficiency.

[0057] The adjustment of the first rotary valve core 2a2 and the second rotary valve core 2b2 is independent and there is no coupling relationship. The dual rotary valve core rectifier module 2 ensures that regardless of whether the single-rod hydraulic cylinder 1 is in the stroke or return stroke, the hydraulic oil of the single-rod hydraulic cylinder 1 enters the high-pressure oil circuit of the hydraulic system and flows back to the single-rod hydraulic cylinder 1 from the low-pressure oil circuit. The dual rotary valve core rectifier module 2 and the electro-hydraulic proportional overflow speed control valve 16 control the output flow and pressure of the single-rod hydraulic cylinder 1 and the input flow and pressure of the hydraulic motor 17, respectively. The control of the dual rotary valve core rectifier module 2 can achieve smooth and efficient rectification. The controller 19 controls the valve opening of the electro-hydraulic proportional overflow speed control valve 16 to achieve a relatively constant speed and output voltage of the generator 18.

[0058] To ensure the stable output power of generator 18 within a certain range, this invention only requires maintaining a stable input flow rate to hydraulic motor 17. Based on the following theoretical model, the opening degree of the electro-hydraulic proportional overflow speed control valve 16 can be deduced from the current flow rate into hydraulic motor 17 detected by second flow meter 8b, the current pressure value of high-pressure accumulator 6a detected by first pressure sensor 7a, and the current pressure value at the input end of hydraulic motor 17 detected by second pressure sensor 7b. By controlling the flow rate into hydraulic motor 17 to a certain level, stable power generation by generator 18 can be achieved. Simultaneously, the required pressure level in high-pressure accumulator 6a for power generation can also be determined. The specific model is as follows:

[0059]

[0060] Where q is the flow rate through the 16th orifice of the electro-hydraulic proportional overflow speed control valve; C d ρ is the flow coefficient of the throttling orifice of the electro-hydraulic proportional relief speed control valve 16; A is the flow area of ​​the throttling orifice of the electro-hydraulic proportional relief speed control valve 16; ρ is the hydraulic oil density; Δp is the pressure difference across the throttling orifice of the electro-hydraulic proportional relief speed control valve 16; m is the throttling index of the electro-hydraulic proportional relief speed control valve 16, m = 0.5 ~ 1.

[0061] If the valve opening of the electro-hydraulic proportional relief speed control valve 16 is set to a fixed value, the flow rate into the hydraulic motor 17, the pressure value of the high-pressure accumulator 6a, and the pressure value at the input end of the hydraulic motor 17 are converted into analog signals and output to the controller. The controller converts these signals into digital signals via A / D conversion and records them. By selecting the pressure difference value across the throttling port of the electro-hydraulic proportional relief speed control valve 16 corresponding to the flow rate setting value into the hydraulic motor 17, the valve opening value of the electro-hydraulic proportional relief speed control valve 16 that enables the generator 18 to operate under rated conditions can be obtained. Finally, the pressure difference value corresponding to the valve opening of each electro-hydraulic proportional relief speed control valve 16 when the flow rate into the hydraulic motor 17 is the set flow rate value is selected as the ideal pressure difference. Then, the relationship between the ideal pressure difference and the valve opening of the electro-hydraulic proportional relief speed control valve 16 is obtained as the control curve of the electro-hydraulic proportional relief speed control valve 16. Based on this, the controller 19 is designed, which can achieve stable power generation of the system.

Claims

1. A dual-rotary-valve-core rectifier wave energy generation hydraulic PTO system, characterized in that: The system includes a single-rod hydraulic cylinder (1), a double rotary valve core rectifier module (2), a high-pressure oil circuit, a low-pressure oil circuit, a power generation module, and a controller. The inlet and outlet ports of the rod chamber of the single-rod hydraulic cylinder (1) are sequentially connected to the double rotary valve core rectifier module (2), the high-pressure oil circuit, the power generation module, and the low-pressure oil circuit, and then connected to the inlet and outlet ports of the rodless chamber of the single-rod hydraulic cylinder (1) via the double rotary valve core rectifier module (2). The power generation module is electrically connected to external electrical equipment. A displacement sensor (1b) is installed on the piston rod in the rod chamber of the single-rod hydraulic cylinder (1), and the extended end of the piston rod is connected to a mechanical float (1a), which floats on the water surface. The controller is electrically connected to the displacement sensor (1b), the double rotary valve core rectifier module (2), the high-pressure oil circuit, and the low-pressure oil circuit. The dual rotary valve core rectifier module (2) includes a first rotary motor (2a1), a first rotary valve core (2a2), a second rotary motor (2b1), and a second rotary valve core (2b2). The output shafts of the first rotary motor (2a1) and the second rotary motor (2b1) are respectively connected to the first rotary valve core (2a2) and the second rotary valve core (2b2). The first rotary valve core (2a2) and the second rotary valve core (2b2) ​​each include three working positions. The second working position of the first rotary valve core (2a2) is between the first working position and the third working position. The first working position of the first rotary valve core (2a2) is close to the first rotary motor (2a1), and the second working position of the second rotary valve core (2b2) ​​is close to the first rotary motor (2a1). Between the working position and the third working position, the first working position of the second rotary valve core (2b2) ​​is close to the second rotary motor (2b1); the second working positions of both the first rotary valve core (2a2) and the second rotary valve core (2b2) ​​are closed; the first and third working positions of both the first and second rotary valve cores (2a2 and 2b2) have an oil inlet and an oil outlet respectively; the oil inlet and outlet of the first working position of both the first rotary valve core (2a2) and the second rotary valve core (2b2) ​​are connected to the input end of the first shut-off valve (4a) of the high-pressure oil circuit section; the oil inlet and outlet of the third working position of both the first rotary valve core (2a2) and the second rotary valve core (2b2) ​​are connected to the output end of the second shut-off valve (4b) of the low-pressure oil circuit section. When the piston rod of the single-rod hydraulic cylinder (1) moves upward, the first rotary valve core (2a2) is in the first working position, and the second rotary valve core (2b2) ​​is in the third working position. The high-pressure oil in the rod chamber of the single-rod hydraulic cylinder (1) is input to the high-pressure oil circuit through the inlet and outlet of the first working position of the first rotary valve core (2a2), and the low-pressure oil in the low-pressure oil circuit flows into the rodless chamber of the single-rod hydraulic cylinder (1) through the third working position of the second rotary valve core (2b2). During the downward movement, the first rotary valve core (2a2) is in the third working position, and the second rotary valve core (2b2) ​​is in the first working position. The high-pressure oil in the rodless chamber of the single-rod hydraulic cylinder (1) is input to the high-pressure oil circuit through the oil inlet and outlet of the second rotary valve core (2b2) ​​at the first working position. The low-pressure oil in the low-pressure oil circuit flows into the rod chamber of the single-rod hydraulic cylinder (1) through the third working position of the first rotary valve core (2a2). The first rotary motor (2a1) and the second rotary motor (2b1) are both electrically connected to the controller. The controller (19) controls the rotation angle of the first rotary motor (2a1) and the second rotary motor (2b1) of the dual rotary valve core rectifier module (2) to adjust the opening of the first rotary valve core (2a2) and the second rotary valve core (2b2). Specifically, based on the area ratio of the rod chamber to the rodless chamber of the single-rod hydraulic cylinder (1), the controller applies control signals to the first rotary motor (2a1) and the second rotary motor (2b1) so that the ratio of the valve opening of the first rotary valve core (2a2) to the valve opening of the second rotary valve core (2b2) ​​is equal to the area ratio of the rod chamber to the rodless chamber of the single-rod hydraulic cylinder (1).

2. The dual rotary valve core rectifier wave energy generation hydraulic PTO system according to claim 1, characterized in that: The high-pressure oil circuit section, along the hydraulic oil transmission direction in the hydraulic PTO system, includes a first shut-off valve (4a), a first flow meter (8a), a high-pressure accumulator module, an electro-hydraulic proportional overflow speed control valve (16), and a second flow meter (8b) connected in sequence. The input end of the first shut-off valve (4a) is connected to the double rotary valve core rectifier module (2), and the output end of the second flow meter (8b) is connected to the input end of the generator module. A second pressure sensor (7b) is connected between the second flow meter (8b) and the generator module. The low-pressure oil circuit section, along the hydraulic oil transmission direction in the hydraulic PTO system, includes a first shut-off valve (4a), a first flow meter (8a), a high-pressure accumulator module, an electro-hydraulic proportional overflow speed control valve (16), and a second flow meter (8b) connected in sequence. The hydraulic oil contamination monitoring module, the low-pressure accumulator module, and the second shut-off valve (4b) are connected. The input end of the hydraulic oil contamination monitoring module is connected to the output end of the power generation module, and the output end of the second shut-off valve (4b) is connected to the double rotary valve core rectifier module (2). A third pressure sensor (7c) is connected between the power generation module and the hydraulic oil contamination monitoring module. The first flow meter (8a), the high-pressure accumulator module, the electro-hydraulic proportional overflow speed control valve (16), the second flow meter (8b), the second pressure sensor (7b), the third pressure sensor (7c), the hydraulic oil contamination monitoring module, and the low-pressure accumulator module are all electrically connected to the controller. The hydraulic PTO system further includes a first pressure regulating oil circuit, an unloading oil circuit, and a second pressure regulating oil circuit. The input end of the first pressure regulating oil circuit is connected between the output end of the first shut-off valve (4a) and the input end of the first flow meter (8a). The output end of the first pressure regulating oil circuit is connected between the input end of the low-pressure accumulator and the output end of the hydraulic oil contamination monitoring module. A safety valve (3) is provided on the first pressure regulating oil circuit, and hydraulic plugs (9) are provided at both ends of the safety valve (3). The input ends of the unloading oil circuit and the second pressure regulating oil circuit are connected sequentially between the input end of the high-pressure accumulator module and the input end of the electro-hydraulic proportional overflow speed control valve (16). The output ends of the second pressure regulating oil circuit and the unloading oil circuit are connected sequentially between the output end of the power generation module and the input end of the hydraulic oil contamination monitoring module. A third solenoid valve (5c) and a proportional overflow valve (15) are provided on the unloading oil circuit and the second pressure regulating oil circuit, respectively. The third solenoid valve (5c) and the proportional overflow valve (15) are both electrically connected to the controller (19).

3. The dual rotary valve core rectifier wave energy generation hydraulic PTO system according to claim 2, characterized in that: The high-pressure accumulator module includes a first solenoid valve (5a), a high-pressure accumulator (6a), and a first pressure sensor (7a). The input end of the first solenoid valve (5a) is connected between the output end of the first flow meter (8a) and the input end of the third solenoid valve (5c) of the unloading oil circuit. The output end of the first solenoid valve (5a) is connected to the high-pressure accumulator (6a). The first pressure sensor (7a) is connected between the first solenoid valve (5a) and the high-pressure accumulator (6a). The low-pressure accumulator module includes a second solenoid valve (5b) and a low-pressure accumulator (6b). The input end of the second solenoid valve (5b) is connected between the input end of the second shut-off valve (4b) and the output end of the safety valve (3) of the first pressure regulating oil circuit. The output end of the second solenoid valve (5b) is connected to the low-pressure accumulator (6b). The first solenoid valve (5a), the second solenoid valve (5b), and the first pressure sensor (7a) are all electrically connected to the controller (19).

4. The dual rotary valve core rectifier wave energy generation hydraulic PTO system according to claim 2, characterized in that: The hydraulic oil contamination monitoring module includes a cooler (10), two filters (11), two pressure test connectors (12), a first check valve (13a), a second check valve (13b), and an online contamination monitor (14). The two pressure test connectors (12) are connected between the output end of the safety valve (3) of the first pressure regulating oil circuit and the output end of the third solenoid valve (5c) of the unloading oil circuit. The two pressure test connectors (12) are sequentially connected to the two filters (11) and the cooler (10) along the transmission direction of the hydraulic oil in the hydraulic PTO system. The two pressure test connectors (12) are also connected to a first check valve (13a) and a second check valve (13b). The input and output ends of the first check valve (13a) are connected to the output and input ends of the second check valve (13b), respectively. The conduction direction of the first check valve (13a) is the same as the transmission direction of the hydraulic oil in the hydraulic PTO system, and the conduction direction of the second check valve (13b) is opposite to the transmission direction of the hydraulic oil in the hydraulic PTO system. An online pollution monitor (14) is also connected between the two pressure test connectors (12). The online pollution monitor (14) is electrically connected to the controller (19).

5. A dual-rotary valve core rectifier wave energy generation hydraulic PTO system according to claim 2, characterized in that: The power generation module includes a third check valve (13c), a hydraulic motor (17), and a generator (18). The input and output ends of the hydraulic motor (17) are respectively connected between the output end of the second flow meter (8b) and the output end of the proportional relief valve (15) of the second pressure regulating oil circuit. The input and output ends of the hydraulic motor (17) are respectively connected between the input and output ends of the third check valve (13c). The rotating shaft of the hydraulic motor (17) is connected to the generator (18), and the generator (18) is electrically connected to an external power supply device. The second pressure sensor (7b) is connected between the output end of the second flow meter (8b) and the input end of the hydraulic motor (17), and the third pressure sensor (7c) is connected between the output end of the hydraulic motor (17) and the output end of the proportional relief valve (15) of the second pressure regulating oil circuit.

6. A control method for a hydraulic PTO system according to any one of claims 1-5, characterized in that: Includes the following steps: Step 1: Initialize the first pressure sensor (7a), second pressure sensor (7b), third pressure sensor (7c) and controller (19) of the hydraulic PTO system. Start the hydraulic PTO system under the preset pressure parameters of the hydraulic PTO system. Open the first shut-off valve (4a), second shut-off valve (4b), first solenoid valve (5a), second solenoid valve (5b) and electro-hydraulic proportional relief speed control valve (16) in sequence, and keep them open when the hydraulic PTO system is working normally. Step 2: Place one or more hydraulic PTO systems in the waves. For each hydraulic PTO system, the mechanical float (1a) connected to the extended end of the piston rod of the single-rod hydraulic cylinder (1) of the hydraulic PTO system reciprocates under the action of the waves, driving the piston rod of the single-rod hydraulic cylinder (1) to reciprocate. The double rotary valve core rectifier module (2) rectifies the bidirectional flow of oil in the high-pressure oil circuit and the low-pressure oil circuit to make it flow in one direction. Finally, the hydraulic energy of the unidirectional flow of oil is converted into rotational mechanical energy by the hydraulic motor (17), and then the rotational mechanical energy is converted into electrical energy by the generator (18) and output to the external electrical equipment.

7. The control method according to claim 6, characterized in that: In step 1, the preset pressure parameters of the hydraulic PTO system include the system pressure of the safety valve (3), the working pressure of the proportional relief valve (15), and the high pressure arrival pressure of the first pressure sensor (7a). The system pressure of the safety valve (3) is higher than the working pressure of the proportional relief valve (15). When the hydraulic PTO system is working normally, the safety valve (3), the third solenoid valve (5c), and the proportional relief valve (15) are all closed. When the hydraulic PTO system is not working normally: when the controller (19) receives the system pressure detected by the pressure sensor (7a) exceeding the system pressure of the safety valve (3), the controller (19) issues an alarm, and the hydraulic PTO system is in an abnormal working state. At this time, the safety valve (3) is opened to unload the oil pressure in the hydraulic PTO system. When the system pressure does not exceed the system pressure of the safety valve (3), the safety valve (3) is closed. When the controller (19) receives the pressure When the working pressure of the hydraulic motor (17) detected by the sensor (7b) exceeds the working pressure of the proportional relief valve (15), the controller (19) issues an alarm, indicating that the hydraulic PTO system is in an abnormal working condition. At this time, the proportional relief valve (15) is opened to unload the oil pressure in the hydraulic PTO system. When the working pressure of the hydraulic motor (17) does not exceed the working pressure of the proportional relief valve (15), the proportional relief valve (15) is closed. When the controller (19) receives the working pressure of the high-pressure accumulator (6a) detected by the first pressure sensor (7a) exceeding the high pressure arrival pressure of the first pressure sensor (7a), the controller (19) issues an alarm, indicating that the hydraulic PTO system is in an abnormal working condition. At this time, the first solenoid valve (5a) is closed. When the working pressure of the high-pressure accumulator (6a) does not exceed the high pressure arrival pressure of the first pressure sensor (7a), the first solenoid valve (5a) is opened.

8. The control method according to claim 7, characterized in that: The hydraulic PTO system is in an abnormal working condition, which also includes: the controller (19) receiving that the output flow and input flow of the hydraulic motor (17) detected by the first flow meter (8a) and the second flow meter (8b) are not within the preset flow range; the controller (19) receiving that the input pressure and output pressure of the hydraulic motor (17) detected by the second pressure sensor (7b) and the third pressure sensor (7c) are not within the preset pressure range; and the controller (19) receiving feedback from the online contamination monitor (14) that the hydraulic PTO system oil is contaminated. The controller (19) issues an alarm in all these cases. At this time, the hydraulic PTO system is put into standby maintenance or shutdown maintenance. Specifically, the double rotary valve core rectifier is first turned off. The first rotary valve core (2a2) and the second rotary valve core (2b2) ​​of block (2) are set to be in their respective second working positions at the same time. The piston rod of the single-rod hydraulic cylinder (1) stops reciprocating. The single-rod hydraulic cylinder (1) oscillates back and forth with the mechanical float (1a) and no longer does work. When the hydraulic PTO system is shut down for maintenance, the first shut-off valve (4a), the second shut-off valve (4b), the first solenoid valve (5a) and the second solenoid valve (5b) must be closed at the same time to cut off the connection between the high-pressure oil circuit and the main oil circuit of the low-pressure oil circuit of the hydraulic PTO system and the single-rod hydraulic cylinder (1). Then, the hydraulic PTO system is put into standby maintenance or shutdown maintenance to restore the hydraulic PTO system to normal working condition. When the hydraulic PTO system is in an abnormal working condition, the controller (19) receives the instantaneous displacement of the piston rod of the single-rod hydraulic cylinder (1) detected by the displacement sensor (1b) as zero. At this time, the controller (19) sets the first rotary valve core (2a2) and the second rotary valve core (2b2) ​​of the dual rotary valve core rectifier module (2) to be in their respective third working positions at the same time, so that the rod chamber and the rodless chamber of the single-rod hydraulic cylinder (1) are connected to the low-pressure oil circuit at the same time. At this time, the hydraulic PTO system does not do work until the controller (19) receives the instantaneous displacement of the piston rod of the single-rod hydraulic cylinder (1) detected by the displacement sensor (1b) as not zero. Then, the controller (19) adjusts the first rotary valve core (2a2) and the second rotary valve core of the dual rotary valve core rectifier module (2) so that the hydraulic PTO system continues to do work and output electrical energy.

9. The control method according to claim 7, characterized in that: In step 2, when the piston rod of the single-rod hydraulic cylinder (1) reciprocates, it converts wave energy into hydraulic energy. When the piston rod of the single-rod hydraulic cylinder (1) moves upward, the controller (19) controls the first rotary motor (2a1) of the double rotary valve core rectifier module (2) to drive the first rotary valve core (2a2) to the first working position, and controls the second rotary motor (2b1) to drive the second rotary valve core (2b2) ​​to the third working position. The high-pressure oil in the rod chamber of the single-rod hydraulic cylinder (1) is forced out and input to the high-pressure oil circuit through the inlet and outlet of the first rotary valve core (2a2) of the double rotary valve core rectifier module (2) at the first working position, and then inputs to the power generation module. The power generation module converts the high-pressure oil into low-pressure oil and inputs it to the low-pressure oil circuit. The low-pressure oil circuit inputs the low-pressure oil through the inlet and outlet of the second rotary valve core (2b2) ​​of the double rotary valve core rectifier module (2) at the third working position. The oil is input to the rodless chamber of the single-rod hydraulic cylinder (1); when the piston rod of the single-rod hydraulic cylinder (1) moves downward, the controller (19) controls the first rotary motor (2a1) of the double rotary valve core rectifier module (2) to drive the first rotary valve core (2a2) to the third working position, and controls the second rotary motor (2b1) to drive the second rotary valve core (2b2) ​​to the first working position. The high-pressure oil in the rodless chamber of the single-rod hydraulic cylinder (1) is forced out and input to the high-pressure oil circuit through the inlet and outlet of the first working position of the second rotary valve core (2b2) ​​of the double rotary valve core rectifier module (2), and then input to the power generation module. The power generation module converts the high-pressure oil into low-pressure oil and inputs it to the low-pressure oil circuit. The low-pressure oil circuit inputs the low-pressure oil to the rod chamber of the single-rod hydraulic cylinder (1) through the inlet and outlet of the third working position of the first rotary valve core (2a2) of the double rotary valve core rectifier module (2).

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