Variable pitch system and wind generating set

Abstract

The invention provides a variable pitch system and a wind generating set, and the variable pitch system comprises a variable pitch oil cylinder which is provided with a rod cavity, a rodless cavity and a piston rod; the variable-pitch control unit is arranged between an oil source and the variable-pitch oil cylinder, and the variable-pitch control unit is communicated with the rod cavity and the rodless cavity, so that a piston rod of the variable-pitch oil cylinder extends out or retracts back to carry out variable-pitch adjustment on blades by switching the flow directions of an oil inlet path and an oil outlet path of the rod cavity and the flow direction of an oil outlet path of the rodless cavity; the anti-vortex unit is connected between one of the rod cavity and the rodless cavity and an oil source, the anti-vortex unit can supply oil to one of the rod cavity and the rodless cavity and can close an oil supply and return path of the other one of the rod cavity and the rodless cavity, so that the piston rod is kept still, and the blades are kept at the anti-vortex angle.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind power generation, and in particular relates to a variable pitch system and a wind power generator set. Background Art

[0002] When fluid (wind) flows over the surface of a slender cylinder (for example, a tower), pairs of antisymmetric vortices will break away downstream due to the instability of the boundary layer. 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) is close to the natural frequency (f) of the tower, the tower vibration is amplified, and the vibration simultaneously reversely affects the flow field, intensifies the excitation, and forms a large amplitude vibration. This fluid-structure coupling phenomenon is called vortex-induced vibration.

[0003] When the 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 means mainly use an electrically controlled variable pitch system to control the variable pitch motor to achieve pitch angle changes and blade locking. However, when the 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 it is impossible 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 power cannot meet the need to lock the blades at a certain angle for a long time. Summary of the invention

[0004] The main purpose of the present disclosure is to provide a variable pitch system and a wind turbine generator set, 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 when power is off.

[0005] In view of the above-mentioned invention objectives, the present disclosure provides the following technical solutions:

[0006] In one aspect of the present disclosure, a pitch system is provided, which includes a pitch cylinder, a pitch control unit and an anti-vortex 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 anti-vortex unit is connected between one of the rod chamber and the rodless chamber and the oil source, and the anti-vortex unit can supply oil to the one and close the oil supply and return path of the other, so that the piston rod remains stationary to keep the blades at the anti-vortex angle.

[0007] According to an exemplary embodiment of the present disclosure, the oil supply and return path includes an emergency propeller oil supply path and a normal pitch oil supply and return path connected in parallel between the rodless chamber and the oil source. When the anti-vortex action of the anti-vortex unit is started, the normal pitch oil supply and return path is in a closed state, and the anti-vortex unit can close the emergency propeller oil supply path.

[0008] Optionally, a directional valve is provided on the emergency propeller-feathering oil supply path for controlling the closing of the emergency variable pitch oil supply path. When the directional valve is closed, the emergency propeller-feathering oil supply path is in a non-conducting state.

[0009] Specifically, the anti-vortex unit includes an anti-vortex drive unit, which is connected to the rod chamber. The directional valve includes a hydraulically controlled one-way valve, the oil control inlet of the hydraulically controlled one-way valve is connected to the anti-vortex drive unit, the oil inlet of the directional valve is connected to the oil source, and the oil outlet of the directional valve is connected to the rodless chamber. When the anti-vortex action of the anti-vortex unit is started, the oil control inlet is connected to close the directional valve, so that the anti-vortex unit can control the directional valve to close.

[0010] Furthermore, the directional valve includes a hydraulically controlled reversing valve, a hydraulically controlled one-way valve or an electromagnetic reversing valve.

[0011] According to another exemplary embodiment of the present disclosure, a first reversing valve is further provided on the emergency propeller oil supply path, an oil inlet of the first reversing valve is connected to an oil source, and an oil outlet of the first reversing valve is connected to an oil inlet of the directional valve.

[0012] Optionally, the pilot ratio of the hydraulically controlled one-way valve is greater than 1.5:1.

[0013] Optionally, a first one-way valve is arranged between the anti-vortex drive unit and the rod chamber, an oil inlet of the first one-way valve is connected to the anti-vortex drive unit, and an oil outlet of the first one-way valve is connected to the rod chamber.

[0014] Specifically, the anti-vortex drive unit is connected to an external oil source through an anti-vortex energy storage path, and a second reversing valve is provided on the anti-vortex energy storage path. The oil inlet of the second reversing valve is connected to the external oil source, and the oil outlet of the second reversing valve is connected to the anti-vortex drive unit. The second reversing valve is turned on to activate the anti-vortex energy storage path.

[0015] Furthermore, an anti-vortex energy release path is also arranged between the anti-vortex drive unit and the oil source, and the anti-vortex energy release path is provided with a third reversing valve, the oil inlet of the third reversing valve is connected to the anti-vortex drive unit, the oil outlet of the third reversing valve is connected to the oil source, and the third reversing valve is turned on to activate the anti-vortex energy release path.

[0016] According to another exemplary embodiment of the present disclosure, the pitch control unit also includes a fourth reversing valve, 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, and the fourth reversing valve 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 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.

[0017] Optionally, a fifth reversing valve is further arranged between the oil inlet of the fourth reversing valve and the oil source, the first oil port of the fifth reversing valve is connected to the oil source, and the second oil port of the fifth reversing valve is connected to the oil inlet of the fourth reversing valve.

[0018] Specifically, a sixth reversing valve is further provided between the first oil supply port and the rodless chamber, a first oil port of the sixth reversing valve is communicated with the first oil supply port, and a second oil port of the sixth reversing valve is communicated with the rodless chamber.

[0019] Furthermore, a seventh reversing valve is arranged between the second oil supply port and the rod chamber, the first oil port of the seventh reversing valve is connected to the rod chamber, the second oil port of the seventh reversing valve is connected to the second oil supply port, and when the anti-vortex action of the anti-vortex unit is started, the seventh reversing valve is in a closed state.

[0020] According to another exemplary embodiment of the present disclosure, a differential circuit is provided between the oil inlet of the fourth reversing valve and the second oil port of the seventh reversing valve, and the differential circuit is provided with a second one-way valve, the oil inlet of the second one-way valve is connected to the second oil port of the seventh reversing valve, and the oil outlet of the second one-way valve is connected to the oil inlet of the fourth reversing valve.

[0021] Optionally, a first oil return path for returning oil to the rod chamber is arranged between the second oil port of the seventh reversing valve and the oil source, an eighth reversing valve is arranged on the first oil return path, the first oil port of the eighth reversing valve is connected with the second oil port of the seventh reversing valve, the second oil port of the eighth reversing valve is connected with the oil source, and the eighth reversing valve is turned on to activate the first oil return path.

[0022] Specifically, 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 is provided on the second oil return path. The oil inlet of the overflow valve is connected to the rodless chamber, and the oil outlet of the overflow valve is connected to the oil source.

[0023] In another aspect of the present disclosure, a wind turbine generator set is provided, wherein the wind turbine generator set comprises the variable pitch system as described above.

[0024] The pitch system and wind turbine generator set provided by the present invention have at least the following beneficial effects: the pitch system provided by the present invention includes a pitch cylinder, a pitch control unit and an anti-vortex unit. When the anti-vortex action of the anti-vortex 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 the rod chamber and the rodless chamber of the pitch cylinder, thereby achieving pressure maintenance in the two cavities of the rod chamber and the rodless chamber, so that the piston rod is maintained at a predetermined position relative to the cylinder body, avoiding pitch rotation of the blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or other objects and advantages of the present disclosure will become more apparent through the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0026] Figure 1 A schematic diagram of a pitch control system according to an exemplary embodiment of the present disclosure.

[0027] Figure 2 for Figure 1 Schematic diagram of the flow direction of hydraulic oil when the anti-vortex unit is in operation.

[0028] Figure 3 for Figure 1 Schematic diagram of the flow of hydraulic oil when the anti-vortex unit stores energy.

[0029] Figure 4 for Figure 1 Schematic diagram of the flow direction of hydraulic oil when the anti-vortex unit releases energy.

[0030] Figure 5 for Figure 1 Schematic diagram of the flow of hydraulic oil during emergency feathering action of the pitch control unit.

[0031] Figure 6 for Figure 1 Schematic diagram of the flow of hydraulic oil during normal speed retraction action of the pitch control unit.

[0032] Figure 7 for Figure 1 Schematic diagram of the flow of hydraulic oil during normal speed propeller opening action of the pitch control unit.

[0033] Figure 8 for Figure 1 Schematic diagram of the flow of hydraulic oil in the variable-rate retracting action of the pitch control unit.

[0034] Description of reference numerals:

[0035] 1. Pitch control unit; 2. Anti-vortex unit;

[0036] 3. Blades; 4. Emergency feathering oil supply path;

[0037] 5. Normal pitch oil supply and return path; 118. Pitch oil cylinder;

[0038] 106. Anti-vortex drive unit; 110. First reversing valve;

[0039] 131. a second reversing valve; 132. a third reversing valve;

[0040] 117, fourth reversing valve; 116, fifth reversing valve;

[0041] 115, sixth reversing valve; 133, seventh reversing valve;

[0042] 123. Eighth reversing valve; 112. Directional valve;

[0043] 114. overflow valve; 134. first check valve;

[0044] 121. second one-way valve; 125. first ball valve;

[0045] 126. Second ball valve; 103. Pressure sensor. DETAILED DESCRIPTION

[0046] Example embodiments will now be described more fully with reference to the accompanying drawings. However, it should not be understood that the implementation of the present disclosure is limited to the embodiments set forth herein. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted.

[0047] The present disclosure provides a variable pitch system suitable for a wind turbine generator set.

[0048] According to an embodiment of the present disclosure, the pitch system includes an anti-vortex unit in addition to a normal pitch control unit. When the pitch control unit loses power and cannot complete the blade locking function in the anti-vortex state, the anti-vortex unit is used to lock the blades at a predetermined pitch angle, thereby enabling the wind turbine to resist vortex-induced vibration.

[0049] Figure 1 FIG. 2 shows a schematic diagram of a pitch control system according to an embodiment of the present invention. Figure 1The pitch system includes a pitch cylinder 118, a pitch control unit 1 and an anti-vortex unit 2. The piston rod of the pitch cylinder 118 is connected to the blades 3 of the wind turbine generator set to drive the blades 3 of the wind turbine generator set to perform pitch operation. 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 pitch operation during grid-connected operation. The anti-vortex 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.

[0050] For example, after the wind turbine generator set has been hoisted but has not yet generated electricity and connected to the grid, the ground power supply system can be used to power the pitch control unit 1, and the pitch control unit 1 can drive the pitch cylinder 118 to change the blade pitch to a predetermined angle, and then the anti-vortex unit 2 can be started to lock the blade. For example, but not limited to, when the anti-vortex unit 2 is in the anti-vortex condition, the anti-vortex unit 2 can keep the blade 3 at a better anti-vortex pitch angle position, and the wind turbine generator set has the ability to resist vortex-induced vibration. For another example, during the process of connecting the wind turbine generator set to the grid for power generation, 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 change the blade pitch to a predetermined angle, and then the anti-vortex unit 2 can be started to lock the blade. The following is combined with Figure 1 The pitch control system is described in detail.

[0051] like Figure 1 As shown, a piston and a piston rod connected to the piston are provided in the pitch cylinder 118, 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 make the blade perform a retracting (also called a feathering) operation and the piston rod is retracted to make the blade perform an opening operation as an example for description or limitation. However, the pitch operation mode is not limited to this. The piston rod may be extended to make the blade perform an opening operation and the piston rod may be retracted to make the blade 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 invention.

[0052] The pitch system includes a pitch cylinder 118, a pitch control unit 1 and an anti-vortex unit 2. The pitch cylinder 118 is used to drive the blades 3 of the wind turbine generator set to pitch. The pitch control unit 1 is arranged between the 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 that the piston rod of the pitch cylinder 118 can be extended or retracted to adjust the pitch of the blades by switching the inlet and outlet oil flow directions of the rod chamber and the rodless chamber. The anti-vortex unit 2 is connected between one of the rod chamber and the rodless chamber and the oil source. The anti-vortex 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 keep the blades at the anti-vortex angle.

[0053] Continuing to refer to the drawings, as an example, this embodiment is described by taking the example that the anti-vortex 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 it is not limited to this.

[0054] In order to supply oil to and return oil to the pitch cylinder 118, the rod chamber of the pitch cylinder 118 is provided with a first oil port, which can be connected to an oil source, so as to be 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, which can be connected to an oil source, so as to be 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.

[0055] 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.

[0056] In this embodiment, the pitch cylinder 118 supplies or discharges hydraulic oil through the first oil port and the second oil port, forming different pressure differences in the rod chamber and the rodless chamber on both sides of the piston to push the piston and the piston rod to move, so that the piston rod extends or retracts relative to the cylinder body, and is used as an actuator to transmit to the blades to complete the pitch adjustment. When the unit is generating electricity normally, the unit itself can also be used to power the unit, switch the various solenoid valves in the pitch control unit 1, and hydraulically control the pitch cylinder 118 to lock the blades at a predetermined angle.

[0057] A pitch control unit is provided between the pitch cylinder 118 and the oil source, and the pitch control unit is used for opening or retracting the blades.

[0058] In the variable pitch system provided by the present disclosure, the anti-vortex 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 generator set is in normal operation, the anti-vortex unit 2 is not started, and the above-mentioned oil supply and return path of the rod chamber is kept in a conductive state, and 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 anti-vortex unit 2 from affecting the normal variable pitch operation of the variable pitch system. When the wind turbine generator set is not connected to the grid or shut down for maintenance, when anti-vortex is required, the anti-vortex unit 2 is started.

[0059] When the anti-vortex unit 2 is started under the anti-vortex condition, 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 maintaining the pressure 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, avoiding pitch rotation of the blades.

[0060] Continue to refer to the attached Figure 1 The oil supply and return path of the rodless chamber includes an emergency propeller oil supply path 4 and a normal pitch oil supply and return path 5 connected in parallel between the rodless chamber and the oil source. When the anti-vortex action of the anti-vortex unit 2 is started, the normal pitch oil supply and return path 5 is in a closed state, and the anti-vortex unit 2 can close the emergency propeller oil supply path 4.

[0061] As an example, the emergency feathering oil supply path 4 may be a redundant path, which may be used as an emergency feathering path and may be turned on when emergency feathering is required (e.g. Figure 5 The normal pitch oil supply and return path 5 may be a common drive path of the pitch cylinder 118. For example, but not limited to, the normal pitch oil supply and return path 5 may be used as an oil supply and return path under the normal speed retraction condition of the pitch cylinder 118 (e.g. Figure 6 ), or the oil supply and return paths under normal propeller speed operation (as shown in Figure 7 ), or the oil supply and return paths under variable speed retracting conditions (as shown in Figure 8 shown).

[0062] When the wind turbine unit 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 enable the wind turbine to resist 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 anti-vortex circuit and other functional circuits to prevent the anti-vortex circuit from affecting the implementation of other functions or being affected by the functions of other circuits.

[0063] In order to improve the safety of the emergency feathering oil supply path 4, specifically, a directional valve 112 is provided on the emergency feathering oil supply path 4 to control the closing of the emergency feathering oil supply path 4. When the directional valve 112 is in a closed state, the emergency feathering oil supply path 4 is in a non-conducting state. Further, the oil inlet of the directional valve 112 is connected to the oil source, and the oil outlet of the directional valve 112 is connected to the rodless chamber. The anti-vortex unit 2 can control the directional valve 112 to close, so that the anti-vortex unit 2 can close the emergency feathering oil supply path. For example, but not limited to, the directional valve 112 can be a one-way valve or a hydraulically controlled reversing valve or an electromagnetic reversing valve, which only allows hydraulic oil to flow from the oil source to the rodless chamber.

[0064] As an example, the anti-vortex unit 2 includes an anti-vortex driving unit 106 , which is in communication with the rod chamber, so that the anti-vortex driving unit 106 can provide hydraulic oil to the rod chamber so that the rod chamber maintains a predetermined pressure.

[0065] When the wind turbine generator set is in a 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.

[0066] As an example, the directional valve 112 includes a hydraulically controlled one-way valve, the oil inlet of which is connected to the oil source, and the oil outlet is connected to the rodless chamber. The oil control inlet of the hydraulically controlled one-way valve is connected to the anti-vortex drive unit 106, so that the anti-vortex drive unit 106 can supply oil to the oil control inlet of the hydraulically controlled one-way valve, thereby controlling the opening or closing of the hydraulically controlled one-way valve. When the anti-vortex unit 2 is started, the oil control inlet is connected to close the directional valve 112, close the forward flow path of the hydraulically controlled one-way valve, and thus close the emergency feathering oil supply path 4, thereby preventing the oil source from supplying oil to the rodless chamber.

[0067] This embodiment is described by taking the anti-vortex unit 2 as a hydraulically controlled one-way valve as an example, and the anti-vortex unit 2 closes the emergency propeller oil supply path by controlling the closing of the hydraulically controlled one-way valve, but the present invention is not limited thereto. As an 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.

[0068] Specific technical details about the hydraulically controlled one-way valve:

[0069] As an example, in this embodiment, the pilot ratio of the hydraulically controlled one-way valve is greater than 1.5:1. When the anti-vortex circuit is started, the oil inlet of the hydraulically controlled one-way valve for forward flow is equal to the pilot control pressure P of the hydraulically controlled one-way valve. At the same time, the rod chamber pressure 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 forward flow, the forward flow channel is opened, and when the pilot control pressure P is greater than the pressure of the oil inlet for forward flow, the forward flow channel is locked. When selecting a hydraulically controlled check valve, the pressure after the valve will offset the pilot control pressure at a 1:1 ratio, that is, the pilot control pressure > the oil inlet pressure of the forward flow + the oil inlet pressure of the forward flow. The hydraulically controlled check valve can only be closed. This is why a pilot ratio greater than 1.5:1 is selected to achieve emergency propeller oil supply line closure.

[0070] 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, emergency propeller oil supply line closure can also be achieved.

[0071] As an example, the pilot ratio of the hydraulically controlled one-way valve in this embodiment is 1.8:1, but it is not limited thereto. When the anti-vortex unit 2 is started, the anti-vortex drive unit 106 can provide hydraulic oil to the oil control inlet of the hydraulically controlled one-way valve to close the forward flow path of the hydraulically controlled one-way valve. At this time, the emergency feathering oil supply path 4 is closed by the anti-vortex unit 2, and the emergency feathering oil supply path 4 cannot supply oil to the rodless chamber.

[0072] Specifically, before the anti-vortex unit 2 is started, the blades are pitched to a predetermined angle through the normal pitch supply and return oil path 5, and then switched to a closed state. At this time, no hydraulic oil flows in the normal pitch supply and return oil path 5. After the anti-vortex unit 2 is started, the anti-vortex drive unit 106 provides high-pressure oil to the oil control inlet of the hydraulically controlled one-way valve, so that the forward flow path of the anti-vortex unit 2 is closed. At this time, the emergency pitch supply oil path 4 is closed, and hydraulic oil cannot be provided from the oil source to the rodless chamber through the emergency pitch supply oil path 4. The anti-vortex drive unit 106 provides high-pressure oil to the rod chamber and closes the oil supply and return path of the rod chamber. Since the normal pitch supply and return oil path 5 is in a closed state, the hydraulic oil cannot enter and exit the rodless chamber through the normal pitch supply and return oil path 5, so that the hydraulic oil cannot enter and exit the rod chamber, and the piston rod is stationary relative to the cylinder body, so that the blade remains at a predetermined angle position.

[0073] When it is necessary to maintain the blades at an optimal anti-vortex pitch angle, the blades can be adjusted to a preferred 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 anti-vortex unit 2 to keep the piston rod stationary relative to the cylinder body, thereby maintaining the angle of the blades and enabling the fan to resist vortex-induced vibration.

[0074] In the pitch control unit 1, further, a first reversing valve 110 is provided on the emergency 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 oil supply path 4. For example, but not limited to, the first reversing valve 110 is in a closed state under normal conditions, and at the same time, the normal pitch supply and return oil path 5 can be in a conducting state, so as to supply oil to the pitch cylinder 118 through the normal pitch supply and return oil path 5, so as to drive the piston rod to extend or retract relative to the cylinder body, thereby realizing the 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.

[0075] As an example, the first reversing valve 110 includes an electromagnetic reversing valve, and the electromagnetic reversing valve is configured such that: when the electromagnetic reversing valve loses power, it is in the left position, at which time the first reversing valve 110 is in the on state, and the electromagnetic reversing valve switches to the right position after being powered on, at which time the first reversing valve 110 is in the closed state. Further, in this embodiment, the first reversing valve 110 is normally in the powered state. Optionally, in this embodiment, the first reversing valve 110 includes a two-position two-way reversing valve, but is not limited thereto.

[0076] In this embodiment, whether the first reversing valve 110 is turned on or off is controlled by controlling the power on or off of the first reversing valve 110. During the grid-connected operation of the wind turbine generator set, the first reversing valve 110 is in the power on state, so that the emergency feathering oil supply path 4 is in the closed state, so that the rodless chamber of the pitch cylinder supplies oil and returns oil through the normal pitching oil supply and return path 5. When the wind turbine generator set is in the shutdown anti-vortex state, the first reversing valve 110 is in the power off state, and thus in the open state, and the opening or closing of the emergency feathering oil supply path 4 is controlled by the directional valve 112.

[0077] In this embodiment, when the first reversing valve 110 loses power and is turned on, and the anti-vortex 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.

[0078] Specifically, refer to Figure 5 , when the normal pitch oil supply and return path 5 is in a closed state and the anti-vortex action of the anti-vortex unit 2 is not started, the first reversing valve 110 loses power and is turned on, and the forward flow path of the directional valve 112 is in a conducting state, and the hydraulic oil in the oil source can enter the rodless cavity through the emergency pitch oil supply path 4, and the hydraulic oil in the rod cavity flows back to the oil source through the oil return path of the rod cavity, but not limited to this. It can be understood that in this embodiment, the oil source can be an oil tank, but not limited to this.

[0079] Furthermore, in order to improve the safety of the emergency oil supply path 4 for feathering, a first ball valve 125 is provided between the oil outlet of the directional valve 112 and the rodless chamber, for overall control of the on-off of the oil supply and return paths in the rodless chamber. The first oil port of the first ball valve 125 is connected to the rodless chamber, and the second oil port of the first ball valve 125 is connected to the oil outlet of the directional valve 112, but not limited thereto. The normal variable pitch oil supply and return path 5 can also be connected to the second oil port of the first ball valve 125, so as to share the first ball valve 125 with the emergency oil supply path 4 for feathering.

[0080] Continuing to refer to the drawings, a first one-way valve 134 is provided between the anti-vortex drive unit 106 and the rod chamber, the oil inlet of the first one-way valve 134 is communicated with the anti-vortex drive unit 106, and the oil outlet of the first one-way valve 134 is communicated with the rod chamber. With such a design, the hydraulic oil can be supplied to the rod chamber through the anti-vortex drive unit 106, so that the rod chamber maintains a certain pressure, and at the same time, the hydraulic oil in the rod chamber can be prevented from flowing back to the anti-vortex drive unit 106, thereby improving the reliability of the anti-vortex unit 2.

[0081] Furthermore, a second ball valve 126 is provided between the oil outlet of the first one-way valve 134 and the rod chamber, for overall control of the on-off of the oil supply and return paths of the rod chamber and the on-off of the oil supply path between the rod chamber and the anti-vortex unit 2. The first oil port of the second ball valve 126 is connected to the rod chamber, and the second oil port of the second ball valve 126 is connected to the oil outlet of the first one-way valve 134, but the present invention is not limited thereto.

[0082] Optionally, in order to improve the reliability of the anti-vortex unit 2, the anti-vortex unit 2 further includes a pressure sensor 103, which is used to monitor the pressure of the hydraulic oil between the rod chamber and the anti-vortex drive unit 106, but the present invention is not limited thereto. Specifically, the pressure sensor 103 is disposed between the anti-vortex drive unit 106 and the oil inlet of the first one-way valve 134, but the present invention is not limited thereto. Optionally, the pressure sensor 103 is disposed close to the anti-vortex drive unit 106, but the present invention is not limited thereto.

[0083] Specifically, refer to Figure 2 When the anti-vortex unit 2 is started, the hydraulic oil of the anti-vortex drive unit 106 flows toward the rod chamber through the first one-way valve 134 and the second ball valve 126 in sequence. At this time, the oil supply pressure of the anti-vortex drive unit 106 is monitored by the pressure sensor 103.

[0084] Reference Figure 3 Furthermore, when the pressure of the anti-vortex drive unit 106 is less than a predetermined value, or when the anti-vortex drive unit 106 does not have a predetermined pressure and is used for the first time, it is necessary to store energy in the anti-vortex drive unit 106 .

[0085] In this embodiment, the anti-vortex drive unit 106 is connected to the external oil source through the anti-vortex energy storage path, and a second reversing valve 131 is provided on the anti-vortex 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 anti-vortex drive unit 106. The second reversing valve 131 is turned on to activate the anti-vortex energy storage path. Optionally, the second reversing valve 131 includes an electromagnetic reversing valve, for example but not limited to, the second reversing valve 131 is a two-position two-way reversing valve.

[0086] When the anti-vortex drive unit 106 needs to store energy, the second reversing valve 131 can be turned on so that the external oil source can enter the anti-vortex drive unit 106 to store energy for the anti-vortex drive unit 106. When the pressure sensor 103 monitors that the pressure of the anti-vortex drive unit 106 reaches a predetermined value, the second reversing valve 131 can be closed to end the energy storage process of the anti-vortex drive unit 106.

[0087] In order to further increase the flow and pressure of the hydraulic oil in the anti-vortex energy storage path, the anti-vortex 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.

[0088] Reference Figure 4 In order to avoid accidental leakage of high-pressure oil of the anti-vortex drive unit 106, or to avoid safety hazards caused by the anti-vortex drive unit 106 maintaining high pressure for a long time, the pressure of the anti-vortex drive unit 106 needs to be released when the anti-vortex unit 2 does not start the anti-vortex action. Specifically, an anti-vortex energy release path is also provided between the anti-vortex drive unit 106 and the oil source, and the anti-vortex energy release path is provided with a third reversing valve 132, the oil inlet of the third reversing valve 132 is connected to the anti-vortex drive unit 106, the oil outlet of the third reversing valve 132 is connected to the oil source, and the third reversing valve 132 is turned on to activate the anti-vortex energy release path.

[0089] In this embodiment, the anti-vortex energy release path is controlled to be turned on or off by turning on or off the third reversing valve 132, so that the pressure of the anti-vortex drive unit 106 is released as needed. Optionally, the third reversing valve 132 includes an electromagnetic reversing valve, for example but not limited to, the third reversing valve 132 is a two-position two-way reversing valve. Optionally, the third reversing valve 132 is set to be electrically turned on, at which time the hydraulic oil can return to the oil source through the third reversing valve 132, and the anti-vortex drive unit 106 can release energy.

[0090] When the anti-vortex action of the anti-vortex unit 2 is not started, the second ball valve 126 can be closed. When the pressure of the anti-vortex drive unit 106 exceeds a predetermined value, the third reversing valve 132 is turned on, and the hydraulic oil of the anti-vortex drive unit 106 flows to the oil source through the third reversing valve 132. In this process, the pressure sensor 103 monitors the pressure of the hydraulic oil flowing out of the anti-vortex drive unit 106 in real time until the pressure value monitored by the pressure sensor 103 reaches a predetermined value, and then the third reversing valve 132 can be closed, thereby ending the energy release process. Optionally, the predetermined value can be 0, but is not limited thereto.

[0091] As an example, during the energy release process of the anti-vortex unit 2, the second ball valve 126 can remain open. When the pressure value of the hydraulic oil provided by the anti-vortex drive 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.

[0092] Optionally, in this embodiment, the anti-vortex drive unit 106 is taken as an accumulator for illustration, but is not limited to this. In addition, the anti-vortex drive unit 106 can also be an oil source with a predetermined pressure, so that the anti-vortex drive unit 106 has the ability to deliver high-pressure oil to the rod chamber.

[0093] It can be understood that in this embodiment, the anti-vortex unit 2 can be provided with a quick connector. When the variable pitch system needs the anti-vortex unit 2, the anti-vortex unit 2 can be quickly connected. When the variable pitch system does not need the anti-vortex unit 2, the anti-vortex unit 2 can be quickly removed, but it is not limited to this.

[0094] Continue 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 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, 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.

[0095] 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.

[0096] In the case of normal pitch change of the wind turbine generator set, the first reversing valve 110 is energized and closed, so that the emergency pitch-feathering oil supply path 4 is closed, and the normal pitch-changing oil supply and return path 5 is in a conducting state, so that the hydraulic oil can enter and exit the rodless cavity through the normal pitch-changing oil supply and return path 5, thereby realizing the extension or retraction of the piston rod to drive the blade pitch change. Further, the normal pitch-changing oil supply and return path 5 includes a second oil supply path of the rodless cavity, and the second oil supply path is different from the emergency pitch-feathering oil supply path 4.

[0097] Specifically, refer to Figure 6 When the fourth reversing valve 117 is turned on 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 in a closed state. At this time, the second oil supply path of the rodless chamber is turned on. 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 the hydraulic oil, the piston rod extends relative to the cylinder body, thereby driving the blades to change pitch.

[0098] In order to improve the reliability of the second oil supply path, a fifth reversing valve 116 is further provided 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 provided 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.

[0099] 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, and the fifth reversing valve 116 is configured to be conducted, but not limited thereto. Optionally, 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, and the sixth reversing valve 115 is configured to be conducted, but not limited thereto.

[0100] Specifically, refer to Figure 6In 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, so that the hydraulic oil is delivered to the rodless chamber.

[0101] The rod chamber and the oil source are connected through a second oil supply and return path, and a seventh reversing valve 133 is provided on the second oil supply and return path. The first oil port of the seventh reversing valve 133 is connected to the rod chamber, and the second oil port of the seventh reversing valve 133 is connected to the oil source. As an 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 is connected to the second oil port of the second ball valve 126, and the first oil port of the seventh reversing valve 133 is connected to the oil outlet of the first check valve 134, and the seventh reversing valve 133 is connected to the oil source.

[0102] In this embodiment, the second oil supply and return path includes a first oil return path between the rod chamber and the oil source, 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, an eighth reversing valve 123 is arranged on the first oil return path, the first oil port of the eighth reversing valve 123 is connected to the second oil port of the seventh reversing valve 133, the second oil port of the eighth reversing valve 123 is connected to the oil source, and the eighth reversing valve 123 is turned on to activate the first oil return path.

[0103] As an example, the seventh reversing valve 133 is a hydraulically controlled reversing valve, for example but not limited to, the seventh reversing valve 133 is a two-position two-way reversing valve. The seventh reversing valve 133 is set to be left-position conduction, at which time the hydraulic oil can flow to the rod chamber through the seventh reversing valve 133 or the hydraulic oil can flow to the oil source through the seventh reversing valve 133, but it is not limited thereto.

[0104] The eighth reversing valve 123 is an electromagnetic reversing valve, for example but not limited to, the eighth reversing valve 123 is a two-position two-way reversing valve. The eighth reversing valve 123 is set to be left-position conduction, at which time the hydraulic oil can flow to the oil source through the eighth reversing valve 123.

[0105] Reference 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.

[0106] Reference Figure 7 Furthermore, the second oil port of the seventh reversing valve 133 is connected to the second oil supply port B through a second oil supply path so that hydraulic oil can be input into the rod chamber.

[0107] When the fourth reversing valve 117 is turned on in the left position, the oil inlet P of the fourth reversing valve 117 is connected to the second oil supply port B, and the first oil supply port A is connected to the oil outlet T. Specifically, 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 leave the fourth reversing valve 117 through the second oil supply port B. At this time, the flow process of the hydraulic oil is: 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, so that the hydraulic oil in the oil source is sent to the rod chamber. At the same time, the hydraulic oil in the rodless chamber is sent to the oil source, and 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.

[0108] Reference Figure 8 A differential circuit is arranged between the oil inlet of the fourth reversing valve 117 and the second oil port of the seventh reversing valve 133, and 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.

[0109] and Figure 6 The same as the embodiment is that, in this embodiment, when the fourth reversing valve 117 is turned on in the right position, 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.

[0110] 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 to the rodless chamber.

[0111] 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.

[0112] Continuing to refer to the attached drawings, a second oil return path for returning oil to the rodless chamber is provided between the rodless chamber and the oil source, and a relief valve 114 is provided on the second oil return path. The oil inlet of the relief valve 114 is connected to the rodless chamber, and the oil outlet of the relief valve 114 is connected to the oil source. In this embodiment, the overload protection function of the variable pitch system is realized by the relief valve 114, and the variable pitch system can be effectively protected from exceeding the maximum load it can withstand during the anti-vortex process, so as to achieve effective overload protection and improve the safety of the variable pitch system.

[0113] Another aspect of the present disclosure provides a wind turbine generator set, which includes the above pitch control system.

[0114] The variable pitch system provided by the present invention includes an anti-vortex unit 2, which 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 blades and realizing the fan's resistance to vortex-induced vibration.

[0115] Figure 2 The diagram of the on-off of the hydraulic circuit under the anti-vortex condition is shown. Under the anti-vortex condition, the anti-vortex drive unit 106 in the anti-vortex circuit can use its own energy storage to control the directional valve 112 to close, and control the oil return path of the rod chamber to close, so as to maintain the pressure of the rod chamber and the rodless chamber of the pitch cylinder 118, so that the piston rod remains stationary relative to the cylinder body, and the blades are kept at the anti-vortex angle position.

[0116] Under different external wind conditions, the anti-vortex angle of the blade will be different. If a mechanical locking pin is used to lock the blade, the blade cannot be locked at a better anti-vortex angle. However, according to an embodiment of the present disclosure, the blade can be driven to pitch to an ideal anti-vortex angle by the pitch cylinder 118, and then the anti-vortex unit 2 can be used to lock the blade at this angle, thereby obtaining a better anti-vortex effect.

[0117] The anti-vortex drive unit 106 can be an accumulator. Before the anti-vortex operation is performed, energy can be stored in the accumulator, for example, hydraulic oil of a predetermined pressure can be filled. After the wind turbine is hoisted and connected to the grid for power generation, the ground power supply can be used to drive the pitch control unit 1 to operate the pitch cylinder 118 to change the blades to the anti-vortex angle, and the accumulator can also be operated to store energy, and then the hydraulic pressure of the system is maintained by the accumulator, and then the external power supply is cut off. During the operation of the wind turbine, if a fault occurs and the turbine needs to be shut down for maintenance, before stopping, the unit's own power supply can be used to drive the pitch control unit 1 to operate the pitch cylinder 118 to change the blades to the anti-vortex angle, and the accumulator can also be operated to store energy, and then the hydraulic pressure of the system is maintained by the accumulator, and then the system is shut down and powered off.

[0118] Reference Figure 4 When the anti-vortex unit 2 releases energy, the third reversing valve 132 is powered and switched to the left position to conduct, the directional valve 112 loses the oil control signal, and the hydraulic oil in the anti-vortex drive 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 anti-vortex unit 2 during the energy release process is: anti-vortex drive 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 blade (as shown in the figure). In addition, the pitch control unit 1 can supply oil to the pitch cylinder 118 for normal pitch change or variable rate retraction (not shown). It can be understood that when the anti-vortex action of the anti-vortex unit 2 is not started, or the anti-vortex unit 2 is in the process of releasing energy, the anti-vortex unit 2 does not affect the working condition of the pitch control unit 1.

[0119] Reference Figure 5 , the first reversing valve 110 is powered off and turned on, the hydraulic oil in the oil source is transported to the rodless chamber through the emergency feathering oil supply path 4, the second ball valve 126, the seventh reversing valve 133 and the eighth reversing valve 123 are all turned on, and the hydraulic oil flow direction of the rodless chamber is roughly: oil source → first reversing valve 110 → direction valve 112 → first ball valve 125 → rodless chamber. At the same time, the hydraulic oil in the rod chamber returns to the oil source, and the flow path of the hydraulic oil is roughly: 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.

[0120] Reference Figure 6, 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 fourth reversing valve 117 → first oil supply port A of fourth reversing valve 117 → sixth reversing valve 115 → first ball valve 125 → rodless chamber, so that the hydraulic oil is delivered 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 connected, and 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. This embodiment can be applied to the normal speed retracting working condition of the variable pitch system, but is not limited to this.

[0121] Reference Figure 7 , the flow process of the hydraulic oil is: 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, so that the hydraulic oil in the oil source is sent into the rod chamber. At the same time, the hydraulic oil in the rodless chamber returns to the oil source, and 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. This embodiment can be applied to the normal speed opening condition of the variable pitch system.

[0122] Reference Figure 8 , 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 sent 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 then is 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 variable pitch cylinder 118, thereby realizing the change and regulation of the retracting speed. According to the wind turbine pitch change requirements, the wind turbine pitch change rate control is realized, and the wind turbine pitch retraction rate is increased while ensuring safety, thereby improving the wind turbine pitch retraction efficiency. This embodiment can be applied to variable rate pitch retraction conditions, but is not limited thereto.

[0123] In the anti-vortex circuit, the anti-vortex drive 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.

[0124] In this embodiment, the anti-vortex unit 2 is modularly designed and is treated as a separate component. It is installed when the variable pitch system has an anti-vortex requirement, and is disassembled and replaced with an oil circuit connecting block when there is no anti-vortex requirement, thereby achieving cost savings.

[0125] The pitch control system provided by the present invention can realize the switching between the anti-vortex function and the pitch control function of the unit without affecting the normal pitch control and emergency pitch feathering operation of the unit.

[0126] When the wind turbine generator set is installed but has not yet started generating electricity, or when it needs to be shut down for maintenance, it is necessary to maintain the pitch angle of the blades 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 anti-vortex circuit (for example, but not limited to, the oil supply and return path between the anti-vortex 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 prevent the anti-vortex circuit from affecting the realization of other functions or being affected by the functions of other circuits.

[0127] Here we mainly consider the relationship between the anti-vortex circuit and the normal variable pitch / variable rate retraction, and the anti-vortex circuit and the emergency feathering circuit.

[0128] The relationship between the anti-vortex circuit and normal pitch control / variable-speed propeller retraction: the pitch control system needs to ensure that during the normal pitch control / variable-speed propeller retraction operation, the anti-vortex action of the anti-vortex circuit stops, for example but not limited to, the seventh reversing valve 133 is in the open state, and the third reversing valve 132 is always energized and in the on state, so that the anti-vortex circuit always releases pressure back to the tank during the normal pitch control process.

[0129] The relationship between the anti-vortex circuit and the emergency propeller-feathering circuit: When the pitch system is in the anti-vortex condition, the emergency propeller-feathering oil supply path cannot pass the accumulator high pressure to the rodless chamber of the pitch cylinder 118. Therefore, in the anti-vortex circuit, it is necessary to consider the closure of the emergency propeller-feathering oil supply path 4 when using the directional valve 112 to realize the anti-vortex function.

[0130] In this embodiment, the emergency feathering oil supply path 4 is connected with the rodless cavity, hydraulic oil is delivered to the rod cavity through the anti-vortex unit 2, and the emergency feathering oil supply path 4 of the rodless cavity is closed by the anti-vortex unit 2, thereby achieving the pressure maintenance of the pitch cylinder 118. As an example, but not limited to this. As needed, the emergency feathering oil supply path can be connected with the rod cavity (not shown), and the anti-vortex unit 2 is set to be able to deliver hydraulic oil to the rodless cavity, and the emergency feathering oil supply path of the rod cavity is closed by the anti-vortex unit 2, thereby achieving the pressure maintenance of the pitch cylinder 118. This is also within the protection scope of the present disclosure. As needed, in this case, the safety protection pressure of the overflow valve 114 on the overload protection path can be adaptively adjusted. For the embodiment of this situation, reference can be made to the above example of the anti-vortex unit being connected to the rodless cavity, and no detailed description will be given.

[0131] Compared with the case where the anti-vortex unit 2 is connected to the rodless cavity of the pitch cylinder 118 and the case where the anti-vortex 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.

[0132] It should be noted that the present disclosure provides Figures 1 to 8 In the figure, 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.

[0133] 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 orientations or positional relationships, are based on the orientations or positional relationships 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 should not be understood as a limitation on the present disclosure.

[0134] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present disclosure, unless otherwise specified, "plurality" means two or more.

[0135] In the description of the present disclosure, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0136] The features, structures or characteristics described in the present disclosure may be combined in one or more embodiments in any suitable manner. 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 variable pitch system, characterized in that: The pitch system comprises: 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; An anti-vortex unit (2) is connected between one of the rod chamber and the rodless chamber and an oil source, and the anti-vortex unit can supply oil to the one and close the oil supply and return path of the other, so that the piston rod remains stationary to keep the blade at the anti-vortex angle.

2. The pitch system according to claim 1, characterized in that: The oil supply and return path comprises an emergency propeller-feathering oil supply path (4) and a normal propeller-changing oil supply and return path (5) connected in parallel between the rodless chamber and the oil source. When the anti-vortex action of the anti-vortex unit is started, the normal propeller-changing oil supply and return path (5) is in a closed state, and the anti-vortex unit can close the emergency propeller-feathering oil supply path (4).

3. The pitch system according to claim 2, characterized in that: 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, characterized in that: The anti-vortex unit comprises an anti-vortex drive unit (106), the anti-vortex drive 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 anti-vortex drive 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 anti-vortex action of the anti-vortex unit is started, the oil control inlet is connected to close the directional valve (112), so that the anti-vortex unit (2) can control the directional valve (112) to close.

5. The pitch system according to claim 3, characterized in that: 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, characterized in that: 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, characterized in that: 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 anti-vortex drive unit (106) and the rod chamber, an oil inlet of the first one-way valve (134) is in communication with the anti-vortex drive unit (106), and an oil outlet of the first one-way valve (134) is in communication with the rod chamber; and / or, The anti-vortex drive unit (106) is connected to an external oil source via an anti-vortex energy storage path, a second reversing valve (131) is provided on the anti-vortex 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 anti-vortex drive unit (106), and the second reversing valve (131) is turned on to activate the anti-vortex energy storage path; and / or, An anti-vortex energy release path is also provided between the anti-vortex drive unit (106) and the oil source, and the anti-vortex energy release path is provided with a third reversing valve (132), the oil inlet of the third reversing valve (132) is connected to the anti-vortex drive unit (106), the oil outlet of the third reversing valve (132) is connected to the oil source, and the third reversing valve (132) is turned on to activate the anti-vortex energy release path.

8. The pitch system according to claim 2, characterized in that: 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, characterized in that: 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 anti-vortex action of the anti-vortex 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, characterized in that: The wind turbine generator set comprises a pitch system as claimed in any one of claims 1 to 9.

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