WIND TURBINE ANGLE CONTROL SYSTEMS, WIND TURBINES, ANGLE HOLDERS, AND WIND FARMING
Patent Information
- Authority / Receiving Office
- VN · VN
- Patent Type
- Applications
- Current Assignee / Owner
- GOLDWIND SCI & TECH CO LTD
- Filing Date
- 2024-10-31
- Publication Date
- 2026-07-01
AI Technical Summary
When the wind turbine is lifted but has not yet generated power, or needs to be shut down and maintained, the blades cannot be continuously supplied to maintain the wind turbine at the vortex-resistant angle, resulting in vortex-excitation vibration problems.
Using a hydraulic system, the blades are locked at a predetermined angle through the pitch cylinder, the pitch control unit and the pitch angle holding unit to ensure that the wind turbine unit can resist vortex when the power is lost.
It is realized that the wind turbine can keep the blades at a predetermined angle when the power is lost, reduce vortex vibration, and improve the wind resistance and reliability of the equipment.
Smart Images
Figure VN1202604039_0
Abstract
Description
Pitch systems, wind turbines and wind farms
[0001] CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] This disclosure claims priority to Chinese patent application No. 202311442307.2 filed on October 31, 2023, the entire contents of which are incorporated herein by reference. Technical Field
[0003] The present disclosure belongs to the technical field of wind power generation, and in particular relates to a variable pitch system, a wind turbine generator set and a wind farm. Background Art
[0004] When fluid (wind) flows over the surface of a slender cylindrical structure (for example, a tower), pairs of antisymmetric vortices are generated downstream due to boundary layer instability. The generation and release of vortices are directly related to the periodic changes in the excitation of the tower surface. When the excitation frequency (fs) approaches the tower's natural frequency (f), the tower vibration is amplified, and the vibration simultaneously reverses the flow field, intensifying the excitation and generating large amplitude vibrations. This fluid-structure interaction phenomenon is called vortex-induced vibration.
[0005] When a wind turbine has been installed but has not yet started generating electricity, or when it needs to be shut down for maintenance, the blades need to be kept at a predetermined pitch angle to allow the wind turbine to resist vortex-induced vibration. Current anti-vortex methods mainly use electrically controlled variable pitch systems to control the variable pitch motors to achieve pitch angle changes and blade locking. However, when a wind turbine has been installed but has not yet started generating electricity, or when it needs to be shut down for maintenance, the entire system of the wind turbine may be in a completely power-off state and unable to continuously supply power to keep the blades at the anti-vortex angle. Even if power can be supplied by batteries or other means, if the unit is in a power-off state for a long time, the battery's electrical energy cannot meet the demand of locking the blades at a certain angle for a long time.
[0006] Summary of the Invention
[0007] The main purpose of the present disclosure is to provide a variable pitch system, a wind turbine generator set and a wind farm, which locks the blades of the wind turbine generator set at a predetermined angle through a hydraulic system, so that the wind turbine generator set can maintain the blades at a predetermined pitch angle even in a power-off state.
[0008] In one aspect of the present disclosure, a pitch system is provided, which includes a pitch cylinder, a pitch control unit and a pitch angle holding unit, wherein the pitch cylinder is provided with a rod chamber, a rodless chamber and a piston rod; the pitch control unit is arranged between an oil source and the pitch cylinder, and the pitch control unit is communicated with the rod chamber and the rodless chamber respectively, so as to extend or retract the piston rod of the pitch cylinder to perform pitch adjustment of the blades by switching the inlet and outlet oil flow directions of the rod chamber and the rodless chamber; the pitch angle holding unit is connected between one of the rod chamber and the rodless chamber and the oil source, and the pitch angle holding unit can supply oil to the one and can close the oil supply and return path of the other, so that the piston rod remains stationary to maintain the blade at a predetermined pitch angle.
[0009] In another aspect of the present disclosure, a wind turbine generator set is provided, wherein the wind turbine generator set includes the pitch control system as described above.
[0010] In another aspect, the present disclosure further provides a wind farm, which includes the wind turbine generator set as described above.
[0011] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The accompanying drawings herein are incorporated into and constitute a part of the specification, illustrate some embodiments consistent with the present disclosure, and together with the description are used to explain the principles of the present disclosure, and do not constitute an improper limitation of the present disclosure.
[0013] FIG1 is a schematic diagram of a pitch control system according to an exemplary embodiment of the present disclosure.
[0014] FIG2 is a schematic diagram showing the flow direction of the hydraulic oil when the pitch angle holding unit in FIG1 is in operation.
[0015] FIG3 is a schematic diagram of the flow direction of the hydraulic oil when the pitch angle holding unit in FIG1 is storing energy.
[0016] FIG4 is a schematic diagram of the flow direction of the hydraulic oil when the pitch angle holding unit in FIG1 releases energy.
[0017] FIG5 is a schematic diagram showing the flow direction of the hydraulic oil for the emergency feathering action of the pitch control unit in FIG1 .
[0018] FIG6 is a schematic diagram showing the flow direction of the hydraulic oil during the normal speed retraction action of the pitch control unit in FIG1 .
[0019] FIG7 is a schematic diagram showing the flow direction of the hydraulic oil during the normal speed propeller opening action of the pitch control unit in FIG1 .
[0020] FIG8 is a schematic diagram showing the flow direction of the hydraulic oil for the variable-speed retracting action of the pitch control unit in FIG1 .
[0021] Explanation of the accompanying symbols: 1. Pitch control unit; 2. Pitch angle holding unit; 3. Blade; 4. Emergency pitch oil supply path; 5. Normal pitch oil supply and return path; 118. Pitch cylinder; 106. Actuating unit; 110. First reversing valve; 131. Second reversing valve; 132. Third reversing valve; 117. Fourth reversing valve; 116. Fifth reversing valve; 115. Sixth reversing valve; 133. Seventh reversing valve; 123. Eighth reversing valve; 112. Directional valve; 114. Overflow valve; 134. First one-way valve; 121. Second one-way valve; 125. First ball valve; 126. Second ball valve; 103. Pressure sensor. DETAILED DESCRIPTION
[0022] Example embodiments will now be described more fully with reference to the accompanying drawings. However, it should not be understood that the embodiments of the present disclosure are limited to the embodiments described herein. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted.
[0023] The present disclosure provides a variable pitch system suitable for a wind turbine generator set.
[0024] According to an embodiment of the present disclosure, the pitch system includes, in addition to a normal pitch control unit, a pitch angle holding unit. When the pitch control unit loses power and cannot complete the blade locking function in the anti-vortex state, the blades are locked at a predetermined pitch angle through the pitch angle holding unit, thereby enabling the wind turbine to resist vortex-induced vibration.
[0025] FIG1 shows a schematic diagram of a pitch system according to an embodiment of the present disclosure. Referring to FIG1 , the pitch system includes a pitch cylinder 118, a pitch control unit 1, and a pitch angle holding unit 2. The piston rod of the pitch cylinder 118 is connected to the blades 3 of the wind turbine generator set, and is used to drive the blades 3 of the wind turbine generator set to perform pitching. The pitch control unit 1 is used to control the operation of the pitch cylinder 118 so that the wind turbine generator set can perform normal pitching operations during grid-connected operation. The pitch angle holding unit 2 is used to lock the blades at a predetermined pitch angle by controlling the oil supply and return paths of the pitch control unit 1 when the wind turbine generator set loses power.
[0026] For example, after the wind turbine generator set is hoisted and before it is connected to the grid for power generation, the ground power supply system can be used to power the pitch control unit 1, and the pitch control unit 1 drives the pitch cylinder 118 to adjust the blade pitch to a predetermined angle, and then the pitch angle holding unit 2 is started to lock the blade. For example, but not limited to, when the pitch angle holding unit 2 is in an anti-vortex condition, the pitch angle holding unit 2 can keep the blade 3 at a preferred anti-vortex pitch angle position. At this time, the wind turbine generator set has the ability to resist vortex-induced vibration. For another example, during the process of grid-connected power generation of the wind turbine generator set, if the wind turbine generator set needs to be shut down for maintenance, the unit's own electrical energy can be used to drive the pitch cylinder 118 through the pitch control unit 1 to adjust the blade pitch to a predetermined angle, and then the pitch angle holding unit 2 is started to lock the blade. The pitch system is described in detail below in conjunction with Figure 1.
[0027] As shown in FIG1 , the pitch cylinder 118 is provided with a piston and a piston rod connected to the piston, thereby dividing the inner cavity of the pitch cylinder 118 into a rod cavity and a rodless cavity. The piston rod is located in the rod cavity, and one end extends from the rod cavity and is connected to the blade 3. The blade is driven to rotate to a predetermined angle by the extension and retraction of the piston rod. In the following embodiments and claims, for the convenience of description, the piston rod is extended to cause the blade to perform a retracting (also called a feathering) operation and the piston rod is retracted to cause the blade to perform an opening operation as an example for description or limitation. However, the pitch operation is not limited to this. The piston rod may be extended to cause the blade to perform an opening operation and the piston rod may be retracted to cause the blade to perform a feathering operation. These are conventional conversion operations that can be understood by those skilled in the art and are not intended to limit the protection of the present disclosure.
[0028] The pitch system includes a pitch cylinder 118, a pitch control unit 1, and a pitch angle holding unit 2. The pitch cylinder 118 is used to drive the blades 3 of the wind turbine generator set to change pitch. The pitch control unit 1 is arranged between the oil source and the pitch cylinder 118, and the pitch control unit 1 is connected to the rod chamber and the rodless chamber respectively. By switching the inlet and outlet oil flow directions of the rod chamber and the rodless chamber, the piston rod of the pitch cylinder 118 is extended or retracted to adjust the pitch of the blades. The pitch angle holding unit 2 is connected between one of the rod chamber and the rodless chamber and the oil source. The pitch angle holding unit 2 can supply oil to the one connected to it and can close the oil supply and return path of the other, so that the piston rod remains stationary to maintain the blade at a predetermined pitch angle, for example but not limited to, the predetermined pitch angle is an anti-vortex angle.
[0029] Continuing to refer to the drawings, as an example, this embodiment is described by taking the example that the pitch angle maintaining unit 2 is connected to the rod chamber of the pitch cylinder 118 to be able to supply oil to the rod chamber and to be able to close the oil supply and return path of the rodless chamber, but is not limited to this.
[0030] To supply and return oil to the pitch cylinder 118, the rod chamber of the pitch cylinder 118 is provided with a first oil port. The first oil port can be connected to an oil source and used as an oil inlet to supply hydraulic oil to the rod chamber, or as an oil outlet to discharge the hydraulic oil in the rod chamber through the first oil port. The rodless chamber is provided with a second oil port. The second oil port can be connected to an oil source and used as an oil inlet to supply hydraulic oil to the rodless chamber, or as an oil outlet to discharge the hydraulic oil in the rodless chamber through the second oil port.
[0031] It can be understood that when the first oil port is used as the oil inlet, the second oil port is used as the oil outlet; when the first oil port is used as the oil outlet, the second oil port is used as the oil inlet.
[0032] In this embodiment, pitch cylinder 118 supplies or discharges hydraulic oil through the first and second oil ports, creating different pressure differentials in the rod chamber and rodless chamber on both sides of the piston, pushing the piston and piston rod to move, thereby extending or retracting the piston rod relative to the cylinder body, acting as an actuator to transmit power to the blades to complete pitch adjustment. When the unit is generating normal power, the unit itself can also be used to power the various solenoid valves in pitch control unit 1, thereby hydraulically controlling pitch cylinder 118 to lock the blades at a predetermined angle.
[0033] A pitch control unit is provided between the pitch cylinder 118 and the oil source, and is used to open or retract the blades.
[0034] In the variable pitch system provided by the present disclosure, the pitch angle holding unit 2 is connected between the rod chamber and the oil source, more specifically, connected to the oil supply and return path of the rod chamber. When the wind turbine is in normal operation, the pitch angle holding unit 2 is not activated, and the above-mentioned oil supply and return path of the rod chamber remains in a conductive state. The valve provided on the oil supply and return path of the rod chamber is used to control the on-off of the return oil path, thereby preventing the pitch angle holding unit 2 from affecting the normal pitch operation of the variable pitch system. When the wind turbine is not connected to the grid or shut down for maintenance, the pitch angle holding unit 2 is activated when anti-vortex is required.
[0035] When the pitch angle maintaining unit 2 is started, it can provide hydraulic oil to the rod chamber and close the oil supply and return path of the rodless chamber to prevent the hydraulic oil from entering and exiting the rodless chamber, so that no hydraulic oil enters and exits the rod chamber and the rodless chamber of the pitch cylinder, thereby achieving pressure maintenance in both the rod chamber and the rodless chamber, so that the piston rod is kept at a predetermined position relative to the cylinder body, avoiding pitch rotation of the blades.
[0036] Continuing to refer to Figure 1, the oil supply and return path of the rodless cavity includes an emergency propeller oil supply path 4 and a normal pitch oil supply and return path 5 connected in parallel between the rodless cavity and the oil source. When the pitch angle holding unit 2 is started, the normal pitch oil supply and return path 5 is in a closed state, and the pitch angle holding unit 2 can close the emergency propeller oil supply path 4.
[0037] As an example, the emergency feathering oil supply path 4 can be a redundant path and can be used as an emergency feathering path, which is opened when emergency feathering is required (as shown in FIG5 ). The normal pitch oil supply and return path 5 can be a normal drive path for the pitch cylinder 118. For example, but not limited to, the normal pitch oil supply and return path 5 can be used as the oil supply and return path for the pitch cylinder 118 under the normal speed retracting condition (as shown in FIG6 ), or the oil supply and return path under the normal speed opening condition (as shown in FIG7 ), or the oil supply and return path under the variable speed retracting condition (as shown in FIG8 ).
[0038] When the wind turbine is hoisted but has not yet started generating electricity, or when it needs to be shut down for maintenance, the blade angle needs to be maintained to prevent the wind turbine from resisting vortex-induced vibration. Since the system may be in a state of complete power failure, it is necessary to comprehensively consider the mutual influence between the pitch angle holding circuit and other functional circuits to prevent the pitch angle holding circuit from affecting the implementation of other functions or being affected by the functions of other circuits.
[0039] To improve the safety of emergency feathering oil supply path 4, a directional valve 112 is provided on emergency feathering oil supply path 4 to control the closure of emergency feathering oil supply path 4. When directional valve 112 is closed, emergency feathering oil supply path 4 is in a non-conductive state. Furthermore, the oil inlet of directional valve 112 is connected to the oil source, and the oil outlet of directional valve 112 is connected to the rodless cavity. Pitch angle holding unit 2 can control directional valve 112 to close, thereby enabling pitch angle holding unit 2 to close the emergency feathering oil supply path. For example, but not limited to, directional valve 112 may be a one-way valve, a hydraulically controlled reversing valve, or a solenoid reversing valve, allowing only hydraulic oil to flow from the oil source to the rodless cavity.
[0040] As an example, the pitch angle holding unit 2 includes an actuating unit 106 , which is in communication with the rod chamber, such that the actuating unit 106 can provide hydraulic oil to the rod chamber, so that the rod chamber maintains a predetermined pressure.
[0041] When the wind turbine generator set is in normal working state, the emergency feathering oil supply path 4 is in a closed state. When the wind turbine generator set is in a shutdown state, the emergency feathering oil supply path 4 is in an open state.
[0042] As an example, directional valve 112 comprises a hydraulically-controlled check valve, whose oil inlet is connected to an oil source and whose oil outlet is connected to the rodless chamber. The oil control inlet of the hydraulically-controlled check valve is connected to actuation unit 106, enabling actuation unit 106 to supply oil to the oil control inlet of the hydraulically-controlled check valve, thereby controlling the opening or closing of the hydraulically-controlled check valve. When pitch angle holding unit 2 is activated, the oil control inlet is opened to close directional valve 112, thereby closing the forward flow path of the hydraulically-controlled check valve and, consequently, the emergency feathering oil supply path 4, thereby preventing the oil source from supplying oil to the rodless chamber.
[0043] This embodiment uses a hydraulically controlled one-way valve as an example to illustrate pitch angle maintaining unit 2. Pitch angle maintaining unit 2 closes the emergency feathering oil supply path by controlling the closing of the hydraulically controlled one-way valve, but the present invention is not limited to this embodiment. By way of example, the hydraulically controlled one-way valve in this embodiment is a one-way valve that is hydraulically controlled to close and has a pilot ratio greater than 1.5:1.
[0044] Specific technical details about the hydraulically controlled one-way valve:
[0045] As an example, in this embodiment, the pilot ratio of the hydraulically controlled one-way valve is greater than 1.5:1. When the pitch angle holding circuit is activated, the oil inlet for the forward flow of the hydraulically controlled one-way valve is equal to the pilot control pressure P of the hydraulically controlled one-way valve. At the same time, the pressure in the rod chamber of the pitch cylinder 118 is also P. Since the area ratio of the rodless chamber to the rod chamber of the pitch cylinder 118 is 2:1, the rodless chamber pressure is 0.5P, that is, the pressure after the hydraulically controlled one-way valve is 0.5P. The opening logic of the hydraulically controlled reversing valve is that when the pilot control pressure P is less than the pressure of the oil inlet for the forward flow, the forward flow channel opens; when the pilot control pressure P is greater than the pressure of the oil inlet for the forward flow, the forward flow channel locks. When selecting a hydraulically controlled check valve, the pressure after the valve will offset the pilot control pressure in a 1:1 ratio. That is, the hydraulically controlled check valve can only be closed when the pilot control pressure is greater than the oil inlet pressure of the forward flow + the oil inlet pressure of the forward flow. This is why a pilot ratio greater than 1.5:1 is selected to achieve emergency propeller oil supply line closure.
[0046] In addition, if the hydraulically controlled one-way valve is replaced by a hydraulically controlled reversing valve, when the pilot pressure is higher than the spring force of the hydraulically controlled reversing valve, the emergency propeller oil supply line can also be closed.
[0047] As an example, the pilot ratio of the hydraulically controlled check valve in this embodiment is 1.8:1, but the present invention is not limited thereto. When the pitch angle holding unit 2 is activated, the actuating unit 106 can supply hydraulic oil to the oil control inlet of the hydraulically controlled check valve, closing the forward flow path of the hydraulically controlled check valve. At this time, the emergency feathering oil supply path 4 is closed by the pitch angle holding unit 2, and the emergency feathering oil supply path 4 cannot supply oil to the rodless chamber.
[0048] Specifically, before the pitch angle holding unit 2 is activated, the blades are pitched to a predetermined angle via the normal pitch oil supply and return path 5 and then switched to a closed state. At this point, no hydraulic oil flows in the normal pitch oil supply and return path 5. After the pitch angle holding unit 2 is activated, the actuating unit 106 supplies high-pressure oil to the oil control inlet of the hydraulically controlled one-way valve, closing the forward flow path of the pitch angle holding unit 2. At this point, the emergency feathering oil supply path 4 is closed, preventing hydraulic oil from being supplied from the oil source to the rodless chamber via the emergency feathering oil supply path 4. The actuating unit 106 supplies high-pressure oil to the rod chamber and closes the rod chamber's oil supply and return path. Because the normal pitch oil supply and return path 5 is closed, hydraulic oil cannot enter or exit the rodless chamber via the normal pitch oil supply and return path 5, nor can it enter or exit the rod chamber. Consequently, the piston rod becomes stationary relative to the cylinder body, thereby maintaining the blades at the predetermined angle.
[0049] When it is necessary to maintain the blades at an optimal anti-vortex pitch angle, the blades can be adjusted to an optimal angle through the pitch cylinder 118, and then the pressure in the rod chamber and the rodless chamber of the pitch cylinder 118 is maintained through the pitch angle maintaining unit 2, so that the piston rod remains stationary relative to the cylinder body, thereby maintaining the angle of the blades and enabling the fan to resist vortex-induced vibration.
[0050] In the pitch control unit 1, a first reversing valve 110 is further provided on the emergency feathering oil supply path 4, which is connected in series with the directional valve 112. The first reversing valve 110 is used to control the opening or closing of the emergency feathering oil supply path 4. For example, but not limited to, the first reversing valve 110 is normally closed, while the normal pitch supply and return oil path 5 can be in a conducting state, so that oil is supplied to the pitch cylinder 118 through the normal pitch supply and return oil path 5 to drive the piston rod to extend or retract relative to the cylinder body, thereby achieving pitch adjustment of the blades. Specifically, the oil inlet of the first reversing valve 110 is connected to the oil source, and the oil outlet of the first reversing valve 110 is connected to the oil inlet of the directional valve 112.
[0051] As an example, the first reversing valve 110 comprises a solenoid reversing valve, and the solenoid reversing valve is configured such that when de-energized, it is in the left position, in which case the first reversing valve 110 is in the on state. Upon energization, the solenoid reversing valve switches to the right position, in which case the first reversing valve 110 is in the closed state. Furthermore, in this embodiment, the first reversing valve 110 is normally energized. Optionally, in this embodiment, the first reversing valve 110 comprises a two-position, two-way reversing valve, but the present invention is not limited thereto.
[0052] In this embodiment, the conduction of first reversing valve 110 is controlled by controlling whether it is energized or de-energized. During grid-connected operation of the wind turbine generator set, first reversing valve 110 is energized, thereby closing emergency feathering oil supply path 4. Oil is then supplied and returned to the rodless chamber of the pitch cylinder via the normal pitch oil supply and return path 5. When the wind turbine generator set is in a shutdown and anti-vortex mode, first reversing valve 110 is de-energized, thereby opening the emergency feathering oil supply path 4. Directional valve 112 controls the opening and closing of emergency feathering oil supply path 4.
[0053] In this embodiment, when the first reversing valve 110 loses power and is turned on, and the pitch angle maintaining unit 2 is not started, the forward flow path of the directional valve 112 is in a conducting state, and the emergency propeller oil supply path 4 is in a conducting state. At this time, the emergency propeller oil supply path 4 can supply oil to the rodless chamber.
[0054] Specifically, referring to Figure 5 , when the normal pitch control oil supply and return path 5 is closed and the pitch angle holding unit 2 is not activated, the first reversing valve 110 loses power and is open, and the forward flow path of the directional valve 112 is open. The hydraulic oil in the oil source can enter the rodless cavity through the emergency feathering oil supply path 4. At this time, the hydraulic oil in the rod cavity flows back to the oil source through the rod cavity's oil return path, but the present invention is not limited to this. It is understood that in this embodiment, the oil source can be a tank, but is not limited to this.
[0055] Furthermore, to enhance the safety of emergency feathering oil supply path 4, a first ball valve 125 is installed between the oil outlet of directional valve 112 and the rodless chamber. This valve provides overall control over the oil supply and return paths within the rodless chamber. The first oil port of first ball valve 125 communicates with the rodless chamber, while the second oil port of first ball valve 125 communicates with the oil outlet of directional valve 112, but this is not limiting. The normal pitch control oil supply and return path 5 can also be connected to the second oil port of first ball valve 125, thereby sharing first ball valve 125 with the emergency feathering oil supply path 4.
[0056] Continuing with the drawings, a first one-way valve 134 is disposed between actuating unit 106 and the rod chamber. The oil inlet of first one-way valve 134 communicates with actuating unit 106, while the oil outlet of first one-way valve 134 communicates with the rod chamber. This design allows hydraulic oil to be supplied to the rod chamber via actuating unit 106, maintaining a constant pressure in the rod chamber. This also prevents hydraulic oil in the rod chamber from flowing back into actuating unit 106, thereby improving the reliability of pitch angle maintaining unit 2.
[0057] Furthermore, a second ball valve 126 is provided between the oil outlet of the first one-way valve 134 and the rod chamber to generally control the opening and closing of the oil supply and return paths of the rod chamber, as well as the opening and closing of the oil supply path between the rod chamber and the pitch angle maintaining unit 2. The first oil port of the second ball valve 126 communicates with the rod chamber, and the second oil port of the second ball valve 126 communicates with the oil outlet of the first one-way valve 134, but the present invention is not limited to this.
[0058] Optionally, to improve the reliability of pitch angle maintaining unit 2, pitch angle maintaining unit 2 further includes a pressure sensor 103. This pressure sensor 103 is used to monitor the pressure of the hydraulic oil between the rod chamber and actuating unit 106, but the present invention is not limited to this. Specifically, pressure sensor 103 is disposed between actuating unit 106 and the oil inlet of first one-way valve 134, but the present invention is not limited to this. Optionally, pressure sensor 103 is disposed near actuating unit 106, but the present invention is not limited to this.
[0059] 2 , when the pitch angle holding unit 2 is started, the hydraulic oil of the actuating unit 106 flows toward the rod chamber through the first one-way valve 134 and the second ball valve 126 in sequence, and the oil supply pressure of the actuating unit 106 is monitored by the pressure sensor 103 .
[0060] 3 , further, when the pressure of the actuating unit 106 is less than a predetermined value, or when the actuating unit 106 does not have a predetermined pressure and is used for the first time, it is necessary to store energy in the actuating unit 106 .
[0061] In this embodiment, the actuating unit 106 is connected to an external oil source via an energy storage path. A second reversing valve 131 is provided on the energy storage path. The oil inlet of the second reversing valve 131 is connected to the external oil source, and the oil outlet of the second reversing valve 131 is connected to the actuating unit 106. When the second reversing valve 131 is turned on, the energy storage path is activated. Optionally, the second reversing valve 131 includes an electromagnetic reversing valve, for example, but not limited to, a two-position, two-way reversing valve.
[0062] When the actuating unit 106 needs to store energy, the second reversing valve 131 can be opened to allow the external oil source to enter the actuating unit 106 to store energy in the actuating unit 106. When the pressure of the actuating unit 106 monitored by the pressure sensor 103 reaches a predetermined value, the second reversing valve 131 can be closed, ending the energy storage process of the actuating unit 106.
[0063] In order to further increase the flow and pressure of the hydraulic oil in the energy storage path, the energy storage path is provided with a throttle valve 113, the first oil port of the throttle valve 113 is connected to the external oil source, and the second oil port of the throttle valve 113 is connected to the oil inlet of the second reversing valve 131, but not limited to this.
[0064] Referring to Figure 4 , to prevent accidental leakage of high-pressure oil in actuating unit 106 or to prevent a potential safety hazard caused by prolonged high pressure in actuating unit 106, the pressure in actuating unit 106 must be released when pitch angle maintaining unit 2 is not activated. Specifically, an energy release path is provided between actuating unit 106 and the oil source. The energy release path includes a third reversing valve 132. The oil inlet of third reversing valve 132 is connected to actuating unit 106, and the oil outlet of third reversing valve 132 is connected to the oil source. When third reversing valve 132 is opened, the energy release path is activated.
[0065] In this embodiment, the energy release path is controlled by opening or closing the third reversing valve 132, thereby releasing pressure from the actuating unit 106 as needed. Optionally, the third reversing valve 132 comprises a solenoid valve, such as, but not limited to, a two-position, two-way reversing valve. Optionally, the third reversing valve 132 is configured to be electrically conductive, allowing the hydraulic oil to return to the oil source through the third reversing valve 132, thereby enabling the actuating unit 106 to release energy.
[0066] When pitch angle holding unit 2 is not activated, second ball valve 126 can be closed. When the pressure in actuating unit 106 exceeds a predetermined value, third reversing valve 132 is opened, causing the hydraulic oil in actuating unit 106 to flow to the oil source through third reversing valve 132. During this process, pressure sensor 103 monitors the pressure of the hydraulic oil flowing out of actuating unit 106 in real time. When the pressure value monitored by pressure sensor 103 reaches a predetermined value, third reversing valve 132 can be closed, thereby ending the energy release process. Optionally, this predetermined value can be 0, but is not limited to this.
[0067] As an example, during the energy release process of the pitch angle maintaining unit 2, the second ball valve 126 can remain open. When the pressure value of the hydraulic oil provided by the actuating unit 106 to the seventh reversing valve 133 is less than a predetermined value, the seventh reversing valve 133 switches to the left position to be open. At this time, the hydraulic oil in the rod chamber of the pitch cylinder 118 flows back to the oil tank through the seventh reversing valve 133.
[0068] Optionally, in this embodiment, the actuating unit 106 is described as an accumulator, but is not limited thereto. In addition, the actuating unit 106 can also be an oil source with a predetermined pressure, so that the actuating unit 106 has the ability to deliver high-pressure oil to the rod chamber.
[0069] It can be understood that in this embodiment, the pitch angle maintaining unit 2 can be provided with a quick connector. When the pitch angle maintaining unit 2 is needed by the pitch system, the pitch angle maintaining unit 2 can be quickly connected. When the pitch angle maintaining unit 2 is not needed by the pitch system, the pitch angle maintaining unit 2 can be quickly removed, but it is not limited to this.
[0070] Continuing to refer to Figures 1 to 8, the pitch control unit 1 also includes a fourth reversing valve 117, which is simultaneously connected to the oil supply path of the rod chamber and the normal pitch supply and return path of the rodless chamber. The fourth reversing valve 117 includes a first oil supply port, a second oil supply port, an oil inlet and an oil return port. The oil inlet of the fourth reversing valve 117 is connected to the pitch drive unit, the oil return port is connected to the oil source, the first oil supply port is connected to the rodless chamber, and the second oil supply port is connected to the rod chamber. By switching the inlet and outlet oil flow directions of the first oil supply port and the second oil supply port, oil can be supplied to the rodless chamber or the rod chamber.
[0071] As an example, the fourth reversing valve 117 can be an electromagnetic reversing valve. For example, but not limited to, the fourth reversing valve 117 can be a three-position four-way reversing valve. When the fourth reversing valve 117 is in the middle position, the fourth reversing valve 117 is in a closed state. At this time, the hydraulic oil cannot pass through the fourth reversing valve 117.
[0072] During normal pitch control of the wind turbine, first reversing valve 110 is energized and closed, closing emergency feathering oil supply path 4. Normal pitch control oil supply and return path 5 is now open, allowing hydraulic oil to flow into and out of the rodless chamber through this path, thereby extending or retracting the piston rod and driving blade pitch control. Furthermore, normal pitch control oil supply and return path 5 includes a second oil supply path for the rodless chamber, which is separate from emergency feathering oil supply path 4.
[0073] Specifically, referring to Figure 6, when the fourth reversing valve 117 is in the right position, the oil inlet P of the fourth reversing valve 117 is connected to the oil source, the first oil supply port A is connected to the rodless chamber, and the second oil supply port B is closed. At this time, the second oil supply path of the rodless chamber is connected. At this time, the hydraulic oil in the oil source can enter the fourth reversing valve 117 through the oil inlet P of the fourth reversing valve 117 and be sent to the rodless chamber through the first oil supply port A. At the same time, the hydraulic oil in the rod chamber is output to the oil source through the second ball valve 126. In this way, during the flow of hydraulic oil, the piston rod extends relative to the cylinder body, thereby driving the blades to change pitch.
[0074] To improve the reliability of the second oil supply path, a fifth reversing valve 116 is further disposed between the oil inlet of the fourth reversing valve 117 and the oil source. The first oil port of the fifth reversing valve 116 is connected to the oil source, and the second oil port of the fifth reversing valve 116 is connected to the oil inlet of the fourth reversing valve 117. A sixth reversing valve 115 is further disposed between the first oil supply port and the rodless chamber. The first oil port of the sixth reversing valve 115 is connected to the first oil supply port, and the second oil port of the sixth reversing valve 115 is connected to the rodless chamber.
[0075] In this embodiment, the fifth reversing valve 116 may be an electromagnetic reversing valve. For example, but not limited to, the fifth reversing valve 116 may be a two-position, two-way reversing valve, which is configured to be open, but is not limited thereto. Alternatively, the sixth reversing valve 115 may be an electromagnetic reversing valve. For example, but not limited to, the sixth reversing valve 115 may be a two-position, two-way reversing valve, which is configured to be open, but is not limited thereto.
[0076] Specifically, referring to Figure 6, in this embodiment, the first oil port of the sixth reversing valve 115 is connected to the first oil supply port A, and the second oil port of the sixth reversing valve 115 is connected to the second oil port of the first ball valve 125. When the fifth reversing valve 116 is turned on, the fourth reversing valve 117 is turned on, the sixth reversing valve 115 is electrically turned on, and the first ball valve 125 is turned on, the hydraulic oil in the oil source is transported to the rodless chamber, and the flow direction of the hydraulic oil is roughly: oil source → fifth reversing valve 116 → oil inlet P of the fourth reversing valve 117 → first oil supply port A of the fourth reversing valve 117 → sixth reversing valve 115 → first ball valve 125 → rodless chamber, thereby sending the hydraulic oil into the rodless chamber.
[0077] The rod chamber and the oil source are connected via a second oil supply / return path. A seventh reversing valve 133 is disposed on this second oil supply / return path. The first oil port of the seventh reversing valve 133 communicates with the rod chamber, while the second oil port of the seventh reversing valve 133 communicates with the oil source. For example, the seventh reversing valve 133 is connected between the second ball valve 126 and the oil source. The first oil port of the seventh reversing valve 133 communicates with the second oil port of the second ball valve 126, and the first oil port of the seventh reversing valve 133 communicates with the oil outlet of the first check valve 134. The outlet of the seventh reversing valve 133 is connected to the oil source.
[0078] In this embodiment, the second oil supply and return path includes a first oil return path between the rod chamber and the oil source, and a first oil return path for supplying rod chamber return oil is arranged between the second oil port of the seventh reversing valve 133 and the oil source. The eighth reversing valve 123 is arranged on the first oil return path, and the first oil port of the eighth reversing valve 123 is connected to the second oil port of the seventh reversing valve 133, and the second oil port of the eighth reversing valve 123 is connected to the oil source. The eighth reversing valve 123 is turned on to activate the first oil return path.
[0079] As an example, the seventh reversing valve 133 is a hydraulically controlled reversing valve, such as, but not limited to, a two-position, two-way reversing valve. The seventh reversing valve 133 is configured to be left-conducting. In this configuration, hydraulic oil can flow through the seventh reversing valve 133 to the rod chamber or to the oil source, but the present invention is not limited thereto.
[0080] The eighth reversing valve 123 is an electromagnetic reversing valve, for example but not limited to, a two-position two-way reversing valve. The eighth reversing valve 123 is set to the left position, at which time the hydraulic oil can flow through the eighth reversing valve 123 to the oil source.
[0081] Referring to Figure 6, when the second ball valve 126 and the seventh reversing valve 133 are both in the on state, the first oil return path of the rod chamber is connected. At this time, the flow direction of the hydraulic oil in the rod chamber is: rod chamber → second ball valve 126 → seventh reversing valve 133 → eighth reversing valve 123 → oil source, so that the hydraulic oil in the rod chamber is output to the oil source.
[0082] 7 , further, the second oil port of the seventh reversing valve 133 is communicated with the second oil supply port B through a second oil supply path, so that hydraulic oil can be input into the rod chamber.
[0083] When the fourth reversing valve 117 is in the left position, its oil inlet P is connected to the second oil supply port B, and its first oil supply port A is connected to the oil outlet T. Specifically, hydraulic oil from the oil source can enter the fourth reversing valve 117 through its oil inlet P and leave the fourth reversing valve 117 through its second oil supply port B. The hydraulic oil then flows through the following process: oil source → fifth reversing valve 116 → oil inlet P of the fourth reversing valve 117 → second oil supply port B of the fourth reversing valve 117 → seventh reversing valve 133 → second ball valve 126 → rod chamber, thereby feeding the hydraulic oil from the oil source into the rod chamber. Simultaneously, the hydraulic oil in the rodless chamber is fed into the oil source. The specific flow path of the hydraulic oil is: rodless chamber → first ball valve 125 → sixth reversing valve 115 → first oil supply port A → oil outlet T → oil source.
[0084] Referring to Figure 8, a differential circuit is provided between the oil inlet of the fourth reversing valve 117 and the second oil port of the seventh reversing valve 133. The differential circuit is provided with a second one-way valve 121. The oil inlet of the second one-way valve 121 is connected to the second oil port of the seventh reversing valve 133, and the oil outlet of the second one-way valve 121 is connected to the oil inlet P of the fourth reversing valve 117.
[0085] The same as the embodiment in Figure 6 is that in this embodiment, when the fourth reversing valve 117 is turned on to the right, and the fifth reversing valve 116 is turned on, the fourth reversing valve 117 is turned on, the sixth reversing valve 115 is electrically turned on, and the first ball valve 125 is turned on, the hydraulic oil in the oil source is transported to the rodless chamber, and the flow direction of the hydraulic oil is roughly: oil source → fifth reversing valve 116 → oil inlet P → first oil supply port A → sixth reversing valve 115 → first ball valve 125 → rodless chamber, so that the hydraulic oil is delivered to the rodless chamber.
[0086] At the same time, the eighth reversing valve 123 loses power and closes, and the hydraulic oil in the rod chamber is transported to the oil source. The flow direction of the hydraulic oil is roughly: rod chamber → second ball valve 126 → seventh reversing valve 133 → eighth reversing valve 123 → oil inlet P → first oil supply port A → sixth reversing valve 115 → first ball valve 125 → rodless chamber, that is, the hydraulic oil flowing out of the rod chamber enters the fourth reversing valve 117, and then is sent into the rodless chamber.
[0087] It can be understood that the second oil port of the seventh reversing valve 133 is connected to the second oil supply port B, and the second oil port of the seventh reversing valve 133 is connected to the first oil port of the eighth reversing valve 123, and the second oil port of the seventh reversing valve 133 is connected to the oil inlet P of the fourth reversing valve 117, but it is not limited to this.
[0088] Continuing with the accompanying drawings, a second oil return path for the rodless chamber is provided between the rodless chamber and the oil source. A relief valve 114 is provided on this second oil return path. The oil inlet of relief valve 114 communicates with the rodless chamber, and the oil outlet of relief valve 114 communicates with the oil source. In this embodiment, relief valve 114 provides overload protection for the pitch system, effectively protecting the pitch system from exceeding its maximum load capacity during the anti-vortex process. This provides effective overload protection and improves the operational safety of the pitch system.
[0089] Another aspect of the present disclosure provides a wind turbine generator set, which includes the above pitch system.
[0090] The variable pitch system provided by the present disclosure includes a pitch angle maintaining unit 2. The pitch angle maintaining unit 2 mainly maintains the pressure in the rod chamber and the rodless chamber of the variable pitch cylinder 118 to keep the piston rod stationary relative to the cylinder body, thereby maintaining the angular position of the blade and realizing the wind turbine's resistance to vortex-induced vibration.
[0091] Figure 2 shows a schematic diagram of the hydraulic circuit's on-off state during anti-vortex operation. During this condition, actuating unit 106 in the pitch angle holding circuit utilizes its stored energy to control the directional valve 112 to close, and the return oil path from the rod chamber to close. This maintains pressure in both the rod and rodless chambers of pitch cylinder 118, keeping the piston rod stationary relative to the cylinder body and maintaining the blades at the anti-vortex angle.
[0092] Under different external wind conditions, the blade's anti-vortex angle will vary. If a mechanical locking pin is used to lock the blade, the blade cannot be locked at the optimal anti-vortex angle. However, according to an embodiment of the present disclosure, the pitch cylinder 118 can be used to drive the blade to the ideal anti-vortex angle, and then the pitch angle holding unit 2 can be used to lock the blade at this angle, thereby achieving a better anti-vortex effect.
[0093] The actuating unit 106 may be an accumulator. Before performing the anti-vortex operation, energy may be stored in the accumulator, for example, hydraulic oil of a predetermined pressure may be filled in the accumulator. After the wind turbine generator set is hoisted and connected to the grid for power generation, the ground power supply may be used to drive the pitch control unit 1 to operate the pitch cylinder 118 to pitch the blades to the anti-vortex angle, and the accumulator may also be operated to store energy, and then the hydraulic pressure of the system may be maintained through the accumulator, and then the external power supply may be cut off. During the operation of the wind turbine generator set, if a fault occurs and the unit needs to be shut down for maintenance, before stopping, the unit's own power supply may be used to drive the pitch control unit 1 to operate the pitch cylinder 118 to pitch the blades to the anti-vortex angle, and the accumulator may also be operated to store energy, and then the hydraulic pressure of the system may be maintained through the accumulator, and then the system may be shut down and powered off.
[0094] Referring to Figure 4, when the pitch angle holding unit 2 releases energy, the third reversing valve 132 is energized and switched to the left position to conduct, the directional valve 112 loses the oil control signal, and the hydraulic oil in the actuating unit 106 of the pitch control unit 1 flows back to the oil tank to release the hydraulic oil. The hydraulic oil path of the pitch angle holding unit 2 during the energy release process is: actuating unit 106 → third reversing valve 132 → oil tank. In this embodiment, the pitch control unit 1 can stop supplying oil to the pitch cylinder 118 to maintain the pitch angle of the blades (as shown in the figure). In addition, the pitch control unit 1 can supply oil to the pitch cylinder 118 for normal pitch or variable rate retraction (not shown). It can be understood that when the pitch angle holding unit 2 is not started or the pitch angle holding unit 2 is in the energy release process, the pitch angle holding unit 2 does not affect the working condition of the pitch control unit 1.
[0095] Referring to Figure 5 , when first reversing valve 110 is de-energized, hydraulic oil in the oil source is delivered to the rodless chamber via emergency feathering oil supply path 4 . Second ball valve 126 , seventh reversing valve 133 , and eighth reversing valve 123 are all open. At this point, the hydraulic oil in the rodless chamber flows in the following general directions: oil source → first reversing valve 110 → directional valve 112 → first ball valve 125 → rodless chamber. Simultaneously, the hydraulic oil in the rod chamber returns to the oil source. The hydraulic oil flows in the following general directions: rod chamber → second ball valve 126 → seventh reversing valve 133 → eighth reversing valve 123 → oil source. This embodiment can be applied to emergency feathering conditions, but is not limited thereto.
[0096] 6 , the hydraulic oil in the oil source is transported to the rodless chamber, and the flow direction of the hydraulic oil is roughly as follows: oil source → fifth reversing valve 116 → oil inlet P of fourth reversing valve 117 → first oil supply port A of fourth reversing valve 117 → sixth reversing valve 115 → first ball valve 125 → rodless chamber, thereby delivering the hydraulic oil into the rodless chamber. When the second ball valve 126, the seventh reversing valve 133, and the eighth reversing valve 123 are all in the conducting state, the first oil return path of the rod chamber is conducted. At this time, the flow direction of the hydraulic oil in the rod chamber is as follows: rod chamber → second ball valve 126 → seventh reversing valve 133 → eighth reversing valve 123 → oil source, thereby outputting the hydraulic oil in the rod chamber to the oil source. This embodiment can be applied to the normal speed retraction working condition of the pitch system, but is not limited thereto.
[0097] Referring to Figure 7 , the hydraulic oil flows as follows: oil source → fifth reversing valve 116 → oil inlet P of fourth reversing valve 117 → second oil supply port B of fourth reversing valve 117 → seventh reversing valve 133 → second ball valve 126 → rod chamber, thereby delivering the hydraulic oil in the oil source into the rod chamber. Simultaneously, the hydraulic oil in the rodless chamber returns to the oil source. The specific hydraulic oil flow path is as follows: rodless chamber → first ball valve 125 → sixth reversing valve 115 → first oil supply port A → oil outlet T → oil source. This embodiment is applicable to the normal speed operation of a variable pitch system.
[0098] 8 , the hydraulic oil in the oil source is transported to the rodless chamber, and the flow direction of the hydraulic oil is roughly as follows: oil source → fifth reversing valve 116 → oil inlet P → first oil supply port A → sixth reversing valve 115 → first ball valve 125 → rodless chamber, thereby sending the hydraulic oil into the rodless chamber. Rod chamber → second ball valve 126 → seventh reversing valve 133 → eighth reversing valve 123 → oil inlet P → first oil supply port A → sixth reversing valve 115 → first ball valve 125 → rodless chamber, that is, the hydraulic oil flowing out of the rod chamber enters the fourth reversing valve 117 and is then sent into the rodless chamber. In this way, the hydraulic oil flowing out of the rod chamber is combined with the high-pressure oil in the rodless chamber and then transported to the rodless chamber. The differential connection of the hydraulic circuit is used to increase the piston rod extension rate of the pitch cylinder 118, thereby achieving the change and adjustment of the propeller retraction speed. According to the wind turbine pitch change requirements, wind turbine pitch change rate control is achieved, and under the premise of ensuring safety, the pitch retraction rate is increased, thereby improving the wind turbine pitch retraction efficiency. This embodiment can be applied to variable rate pitch retraction working conditions, but is not limited thereto.
[0099] In the pitch angle holding circuit, the actuating unit 106 is used to provide continuous pressure maintenance for the directional valve 112, the seventh reversing valve 133 and the rod chamber of the pitch cylinder, which can meet the requirements of the wind turbine to maintain the blade angle position during a long anti-vortex process.
[0100] In this embodiment, the pitch angle maintaining unit 2 is modularly designed. The pitch angle maintaining unit 2 is treated as a separate component and is installed when the variable pitch system has an anti-vortex requirement. When there is no anti-vortex requirement, it is disassembled and replaced with an oil circuit connecting block, thereby achieving cost savings.
[0101] The variable pitch system provided by the present disclosure can realize the switching between the unit's anti-vortex function and the variable pitch function without affecting the unit's normal variable pitch and emergency feathering operations.
[0102] When the wind turbine generator set is hoisted and has not yet started generating electricity, or when it needs to be shut down for maintenance, it is necessary to maintain the blade pitch angle to enable the wind turbine to resist vortex-induced vibration. Since the pitch system may be in a state of complete power failure, it is necessary to comprehensively consider the mutual influence between the pitch angle holding circuit (for example, but not limited to, the oil supply and return path between the pitch angle holding unit and the pitch cylinder) and other functional circuits (for example, but not limited to, the oil supply and return path of the pitch control unit 1) to avoid the pitch angle holding circuit affecting the implementation of other functions or being affected by the functions of other circuits.
[0103] Here we mainly consider the relationship between the pitch angle holding circuit and the normal variable pitch / variable rate retraction, and the pitch angle holding circuit and the emergency propeller circuit.
[0104] The relationship between the pitch angle holding circuit and the normal pitch change / variable rate retraction: The pitch change system needs to ensure that during the normal pitch change / variable rate retraction operation, the anti-vortex action of the pitch angle holding circuit stops, for example but not limited to, the seventh reversing valve 133 is in the open state, and at the same time the third reversing valve 132 is always energized and in the on state, so that the pitch angle holding circuit always relieves pressure back to the oil tank during the normal pitch change process.
[0105] The relationship between the pitch angle holding circuit and the emergency feathering circuit: When the pitch system is in anti-vortex working condition, the emergency feathering oil supply path cannot pass the accumulator high pressure to the rodless chamber of the pitch cylinder 118. Therefore, in the pitch angle holding circuit, it is necessary to consider the closure of the emergency feathering oil supply path 4 when using the directional valve 112 to achieve the anti-vortex function.
[0106] In this embodiment, the example of an emergency feathering oil supply path 4 communicating with the rodless cavity, delivering hydraulic oil to the rodless cavity via the pitch angle holding unit 2, and closing the emergency feathering oil supply path 4 of the rodless cavity by the pitch angle holding unit 2, thereby maintaining pressure in the pitch cylinder 118, is used for illustration, but the present invention is not limited thereto. As needed, the emergency feathering oil supply path can be communicated with the rodless cavity (not shown), with the pitch angle holding unit 2 configured to deliver hydraulic oil to the rodless cavity, and closing the emergency feathering oil supply path of the rodless cavity by the pitch angle holding unit 2, thereby maintaining pressure in the pitch cylinder 118. This is also within the scope of the present disclosure. In this case, as needed, the safety protection pressure of the relief valve 114 on the overload protection path can be adaptively adjusted. For embodiments of this situation, reference can be made to the above example of a pitch angle holding unit communicating with the rodless cavity, and no further detailed description will be given.
[0107] Compared with the case where the pitch angle holding unit 2 is connected to the rodless cavity of the pitch cylinder 118 and the case where the pitch angle holding unit 2 is connected to the rod cavity of the pitch cylinder 118, the safety pressure threshold of the entire pitch system is lower and the safety is better.
[0108] It should be noted that in Figures 1 to 8 provided by the present disclosure, the P port at the outer frame boundary of each figure represents the oil supply port of the variable pitch system, the T port represents the oil return port of the variable pitch system, the ACC represents the oil supply port of the external oil source, and the L represents the oil drain port of the variable pitch system.
[0109] According to another aspect of the present application, a wind farm is provided, which includes a wind turbine generator set provided with any of the aforementioned variable pitch systems.
[0110] The present disclosure provides a variable pitch system and a wind turbine generator set, wherein the variable pitch system includes a variable pitch cylinder, a variable pitch control unit and a pitch angle maintaining unit. When the pitch angle maintaining unit is started, hydraulic oil can be provided to the rod chamber, and the oil supply and return path of the rodless chamber can be closed to prevent hydraulic oil from entering and exiting the rodless chamber, so that no hydraulic oil enters and exits both the rod chamber and the rodless chamber of the variable pitch cylinder, thereby achieving pressure maintenance in both the rod chamber and the rodless chamber, so that the piston rod is maintained at a predetermined position relative to the cylinder body, and pitch rotation of the blades is avoided.
[0111] In the description of the present disclosure, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure.
[0112] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout this disclosure, unless otherwise specified, "plurality" means two or more.
[0113] In the description of this disclosure, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections, electrical connections, or communication connections; they may refer to direct connections or indirect connections through an intermediate medium; they may refer to internal communication between two components or an interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this disclosure based on specific circumstances.
[0114] The features, structures or characteristics described in the present disclosure may be combined in any suitable manner in one or more embodiments. In the above description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of the specific details, or other methods, components, materials, etc. may be adopted. In other cases, known structures, materials or operations are not shown or described in detail to avoid blurring the various aspects of the present disclosure.
Claims
1. A pitch control system, the pitch control system comprising: The pitch cylinder (118) is provided with a rod chamber, a rodless chamber and a piston rod; A pitch control unit (1) is arranged between an oil source and the pitch cylinder (118), and the pitch control unit (1) is respectively connected to the rod chamber and the rodless chamber, so as to extend or retract the piston rod of the pitch cylinder (118) to adjust the pitch of the blades by switching the inlet and outlet oil flow directions of the rod chamber and the rodless chamber; A pitch angle holding unit (2) is connected between one of the rod chamber and the rodless chamber and an oil source, and the pitch angle holding unit is capable of supplying oil to the one and closing the oil supply and return path of the other, so that the piston rod remains stationary to keep the blade at a predetermined pitch angle.
2. The pitch system according to claim 1, wherein: The oil supply and return path comprises an emergency oil supply path (4) connected in parallel between the rodless chamber and the oil source and a normal variable pitch oil supply and return path (5); when the pitch angle holding unit is started, the normal variable pitch oil supply and return path (5) is in a closed state, and the pitch angle holding unit is capable of closing the emergency oil supply path (4).
3. The pitch system according to claim 2, wherein: The emergency propeller oil supply path (4) is provided with a directional valve (112) for controlling the closing of the emergency propeller oil supply path (4); when the directional valve (112) is in a closed state, the emergency propeller oil supply path (4) is in a closed state.
4. The pitch system according to claim 3, wherein: The pitch angle holding unit comprises an actuating unit (106), the actuating unit (106) is connected to the rod chamber, the directional valve (112) comprises a hydraulically controlled one-way valve, the oil control inlet of the hydraulically controlled one-way valve is connected to the actuating unit (106), the oil inlet of the directional valve (112) is connected to an oil source, and the oil outlet of the directional valve (112) is connected to the rodless chamber. When the pitch angle holding unit is started, the oil control inlet is connected to close the directional valve (112), so that the pitch angle holding unit (2) can control the directional valve (112) to close.
5. The pitch system according to claim 3, wherein: The directional valve (112) comprises a hydraulically controlled reversing valve, a hydraulically controlled non-return valve or an electromagnetic reversing valve.
6. The pitch system according to claim 3, wherein: A first reversing valve (110) is also provided on the emergency propeller-feathering oil supply path (4); an oil inlet of the first reversing valve (110) is connected to an oil source, and an oil outlet of the first reversing valve (110) is connected to an oil inlet of the directional valve (112).
7. The pitch system according to claim 4, wherein: The pilot ratio of the hydraulically controlled one-way valve is greater than 1.5:1; and / or, A first one-way valve (134) is provided between the actuating unit (106) and the rod chamber, an oil inlet of the first one-way valve (134) is communicated with the actuating unit (106), and an oil outlet of the first one-way valve (134) is communicated with the rod chamber; and / or, The actuating unit (106) is connected to an external oil source via an energy storage path, a second reversing valve (131) is provided on the energy storage path, an oil inlet of the second reversing valve (131) is connected to the external oil source, an oil outlet of the second reversing valve (131) is connected to the actuating unit (106), and the second reversing valve (131) is turned on to activate the energy storage path; and / or, An energy release path is also provided between the actuating unit (106) and the oil source, and a third reversing valve (132) is provided in the energy release path. The oil inlet of the third reversing valve (132) is connected to the actuating unit (106), and the oil outlet of the third reversing valve (132) is connected to the oil source. The third reversing valve (132) is turned on to activate the energy release path.
8. The pitch system according to claim 2, wherein: The pitch control unit (1) also includes a fourth reversing valve (117), which is simultaneously connected to the oil supply path of the rod chamber and the normal pitch oil supply and return path of the rodless chamber. The fourth reversing valve (117) includes a first oil supply port, a second oil supply port, an oil inlet port and an oil return port. The oil inlet port of the fourth reversing valve (117) is connected to the pitch drive unit, and the oil return port is connected to the oil source. The first oil supply port is connected to the rodless chamber, and the second oil supply port is connected to the rod chamber. By switching the inlet and outlet oil flow directions of the first oil supply port and the second oil supply port, oil can be supplied to the rodless chamber or the rod chamber.
9. The pitch system according to claim 8, wherein: A fifth reversing valve (116) is further provided between the oil inlet of the fourth reversing valve (117) and the oil source, a first oil port of the fifth reversing valve (116) being in communication with the oil source, and a second oil port of the fifth reversing valve (116) being in communication with the oil inlet of the fourth reversing valve (117); and / or, A sixth reversing valve (115) is further provided between the first oil supply port and the rodless chamber, the first oil port of the sixth reversing valve (115) is communicated with the first oil supply port, and the second oil port of the sixth reversing valve (115) is communicated with the rodless chamber; and / or, A seventh reversing valve (133) is further provided between the second oil supply port and the rod chamber, a first oil port of the seventh reversing valve (133) is communicated with the rod chamber, a second oil port of the seventh reversing valve (133) is communicated with the second oil supply port, and when the pitch angle holding unit is started, the seventh reversing valve (133) is in a closed state; and / or, A second oil return path for returning oil to the rodless chamber is provided between the rodless chamber and the oil source, and an overflow valve (114) is provided on the second oil return path. The oil inlet of the overflow valve (114) is connected to the rodless chamber, and the oil outlet of the overflow valve (114) is connected to the oil source.
10. A wind turbine generator set, comprising a variable pitch system according to any one of claims 1 to 9.
11. A wind farm, comprising the wind turbine generator set according to claim 10.