Hydraulic yaw system and wind turbine generator set

Abstract

This disclosure provides a hydraulic yaw system and a wind turbine generator set. The hydraulic yaw system includes: a hydraulic motor having a first inlet / outlet and a second inlet / outlet; a digital servo valve, with a first port and a second port connected to the second inlet / outlet and the first inlet / outlet, respectively; a mechanical feedback mechanism, with its input end connected to the output shaft of the hydraulic motor and its output end coupled to the valve core of the digital servo valve; a hydraulic drive module connected to a third port of the digital servo valve and supplying hydraulic oil to the hydraulic motor via the digital servo valve; and a hydraulic oil collection module connected to a fourth port of the digital servo valve. The hydraulic yaw system of this disclosure enables passive yaw in the event of a power outage.

Description

Technical Field

[0001] This disclosure relates generally to the field of wind power, and more specifically to a hydraulic yaw system and a wind turbine generator set. Background Technology

[0002] Most existing hydraulic yaw systems use proportional valves to control hydraulic motors. By adjusting the opening of the proportional valve, the rotational speed (i.e., yaw speed) of the hydraulic motor is controlled.

[0003] When the external force and the driving force are in the same direction, the speed of the hydraulic motor exceeds the rated speed. At this time, the opening size of the proportional valve can be adjusted by the yaw controller to achieve yaw speed control.

[0004] However, hydraulic systems controlled by proportional valves require sensors to detect yaw speed and the controller to make dynamic adjustments, resulting in long response times and potentially causing the yaw speed to exceed the allowable value.

[0005] When there is no power supply, the wind turbine cannot achieve passive yaw, which causes vortex-induced vibration of the unit due to the yaw angle of the wind turbine not being in the wind. Summary of the Invention

[0006] One of the objectives of the exemplary embodiments disclosed herein is to provide a hydraulic yaw system capable of passive yaw in the event of a power outage.

[0007] One of the objectives of the exemplary embodiments disclosed herein is to provide a hydraulic yaw system capable of automatically adjusting yaw speed without the need for controller intervention.

[0008] According to a first aspect of this disclosure, a hydraulic yaw system is provided, comprising: a hydraulic motor having a first inlet / outlet and a second inlet / outlet; a digital servo valve having a first port and a second port connected to the second inlet / outlet and the first inlet / outlet, respectively; a mechanical feedback mechanism having an input end connected to the output shaft of the hydraulic motor and an output end coupled to the valve core of the digital servo valve; a hydraulic drive module connected to a third port of the digital servo valve and supplying hydraulic oil to the hydraulic motor via the digital servo valve; and a hydraulic oil collection module connected to a fourth port of the digital servo valve.

[0009] Optionally, the mechanical feedback mechanism can control the valve core movement of the digital servo valve to reduce the yaw speed in response to a yaw speed greater than a first specified speed; and control the valve core movement of the digital servo valve to increase the yaw speed in response to a yaw speed less than a second specified speed, wherein the first specified speed is greater than or equal to the second specified speed.

[0010] Optionally, the hydraulic yaw system may further include: a first shuttle valve having a first inlet, a second inlet, and a first outlet; and a second shuttle valve having a third inlet, a fourth inlet, and a second outlet, wherein the first inlet and the second inlet are respectively connected to the first inlet / outlet and the second inlet / outlet, the first outlet is connected to the third inlet, the fourth inlet is connected to the third outlet, and the second outlet is connected to the brake.

[0011] Optionally, the hydraulic yaw system may also include an accumulator connected to a second output port.

[0012] Optionally, the hydraulic yaw system may also include a normally open valve, with the first port of the normally open valve connected to the third port and the second port of the normally open valve connected to the fourth port.

[0013] Optionally, in response to an external force direction being a first direction and the hydraulic yaw system being in a non-electric passive yaw mode, the valve core of the digital servo valve opens in conjunction with a mechanical feedback mechanism, sequentially forming a hydraulic circuit consisting of a first inlet / outlet port, a first port, a third port, a first oil port, a second oil port, a fourth port, a second port, and a second inlet / outlet port; in response to an external force direction being a second direction opposite to the first direction and the hydraulic yaw system being in a non-electric passive yaw mode, the valve core of the digital servo valve opens in conjunction with a mechanical feedback mechanism, sequentially forming a hydraulic circuit consisting of a second inlet / outlet port, a second port, a fourth port, a second oil port, a first oil port, a third port, a first port, and a first inlet / outlet port.

[0014] Optionally, the digital servo valve can be a three-position four-way digital servo valve, where the first port, second port, third port, and fourth port can be port B, port A, port P, and port T, respectively.

[0015] Optionally, the hydraulic oil collection module may include: a fan motor, with a first working port of the fan motor connected to a second port and a second oil port; a radiator, with the second working port of the fan motor connected to the first working port of the radiator; and an oil tank, with the second working port of the radiator connected to the oil tank.

[0016] Optionally, the hydraulic drive module may include a motor and a hydraulic pump connected to the motor. The hydraulic yaw system also includes a first check valve and a first relief valve. The first working port of the hydraulic pump is connected to the oil tank, the second working port of the hydraulic pump is connected to the input port of the first check valve, and the output port of the first check valve is connected to a third port and connected to the oil tank via the first relief valve.

[0017] According to a second aspect of this disclosure, a wind turbine generator set is provided, which includes the aforementioned hydraulic yaw system.

[0018] The hydraulic yaw system according to the embodiments of this disclosure can be yawed by the wind when the unit is completely de-energized, avoiding the risk of the wind turbine tower collapsing due to vortex-induced vibration caused by the unit yaw not being in the wind, thus protecting the safety of the unit.

[0019] The hydraulic yaw system according to embodiments of the present disclosure can keep the brake in a released state during active yaw, passive yaw, and power-off passive yaw, ensuring smooth and unobstructed yaw action and improving system safety and reliability. Attached Figure Description

[0020] These and / or other aspects and advantages of this disclosure will become clearer and more readily understood from the following description of embodiments, taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of a hydraulic yaw system according to an embodiment of the present disclosure; Figure 2 This is a schematic diagram illustrating the connection method between a digital servo valve and a hydraulic motor according to an embodiment of the present disclosure; Figure 3 A schematic diagram of the yaw drive process oil circuit according to an embodiment of the present disclosure is shown; Figure 4 A schematic diagram of a hydraulic circuit is shown when the hydraulic motor speed is insufficient according to an embodiment of the present disclosure; Figure 5 A schematic diagram of the hydraulic circuit when the hydraulic motor overspeeds according to an embodiment of the present disclosure is shown; Figure 6 A schematic diagram of the hydraulic circuit under passive yaw conditions according to an embodiment of the present disclosure is shown; Figure 7 A schematic diagram of the hydraulic circuit under non-electric passive yaw conditions according to an embodiment of the present disclosure is shown; and Figure 8 A schematic diagram of the drive oil circuit of a brake according to an embodiment of the present disclosure is shown. Detailed Implementation

[0021] The following detailed description is provided to aid in obtaining a full understanding of the methods, apparatus, and / or systems described herein. However, the order of operations described herein is merely illustrative and is not limited to those orders set forth herein; equivalent substitutions or changes may be made, except for operations that must occur or be performed in a specific order. Furthermore, for clarity and conciseness, descriptions of content well-known in the art will be omitted or simplified.

[0022] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains upon understanding this disclosure. Unless expressly defined herein, terms (such as those defined in a general dictionary) shall be interpreted as having a meaning consistent with their meaning in the context of the relevant field and in this disclosure, and shall not be interpreted in an idealized or overly formalistic manner.

[0023] Unless otherwise specified, the same reference numerals generally refer to the same elements (e.g., components, steps, and methods). Reference numerals described in previous embodiments that reappear in later embodiments may be omitted. Furthermore, technical features described in different or the same embodiments can be combined in any way, as long as the combined embodiment or technical solution is complete and can solve the technical problems of this application or achieve the technical effects described or not described in this disclosure but which can be determined based on the complete technical solution described above.

[0024] In this disclosure, "connection" or "connection" encompasses not only physical, direct, rigid connections but also extends to the connectivity between fluid pathways. For example, it refers not only to the physical connection between two components via rigid pipes, hoses, or integrated blocks but also to the state where the fluid medium can flow freely. When "connection" is mentioned, it includes not only the physical connections mentioned above but also logical connections. This means that even if components are not physically directly connected, as long as they can indirectly form a fluid pathway through control elements (e.g., valves) or other functional components (e.g., filters, accumulators, etc.), they can be considered to be in a "connected" state. For example, a solenoid directional valve can be used to switch the fluid flow direction under different operating conditions, thereby changing the operating mode of the actuator.

[0025] Similar to the statement that A and B are connected or linked, it can include cases where A and B are directly connected or linked, as well as cases where A and B are connected or linked through at least one other intermediate component. The connection or link between a port or end of the same component and another component generally refers to the flow of hydraulic oil through that port or end through that other component. The terminology of this disclosure is briefly described below.

[0026] Passive yaw: A type of yaw mechanism for wind turbine generators, specifically referring to a yaw method in which the wind turbine yaws against the wind by relying on the wind itself through relevant mechanisms (such as tail rudder, steering wheel, etc.).

[0027] When a wind turbine is without power for various reasons, it cannot perform active yaw. The nacelle remains at a fixed angle, resulting in a deviation in the yaw system's angle relative to the wind. Due to vortex-induced vibration, this causes vibration in the wind turbine, potentially leading to tower collapse. The hydraulic yaw system disclosed herein can utilize wind to move the nacelle of the wind turbine away from the wind direction, even in the absence of power. By positioning the turbine nose away from the wind, vibration is eliminated, protecting the turbine's safety.

[0028] The hydraulic yaw system disclosed herein utilizes a mechanical feedback mechanism to automatically adjust the valve opening. When the yaw speed is greater than or equal to the set speed, the valve opening decreases, and the hydraulic motor speed (i.e., yaw speed) will decrease to prevent the yaw speed from exceeding the set speed. When the yaw speed is less than the set speed, the valve opening increases, and the hydraulic motor speed will increase. The yaw speed can be controlled through the mechanical feedback mechanism without the participation of a controller.

[0029] In the absence of a power source, ordinary proportional valves or solenoid valves will not function. The digital servo valve of the hydraulic yaw system disclosed herein can be opened through a mechanical feedback mechanism, creating a hydraulic flow path and providing damping, enabling passive yaw under power failure conditions. The following is a detailed description of embodiments of this disclosure.

[0030] Figure 1 This is a schematic diagram of a hydraulic yaw system according to an embodiment of the present disclosure; Figure 2 This is a schematic diagram illustrating the connection method between a digital servo valve and a hydraulic motor according to an embodiment of the present disclosure.

[0031] Reference Figure 1 The hydraulic yaw system according to embodiments of the present disclosure may include hydraulic motors 7.1 and 7.2, digital servo valve 5, mechanical feedback mechanism 6, hydraulic drive modules 1 and 2, and hydraulic oil collection module 16.

[0032] Hydraulic motors 7.1 and 7.2 are mechanically connected to the yaw gear ring via a reducer. As an example, hydraulic motors 7.1 and 7.2 can be mounted on the output end of the reducer, with their output shafts coaxially connected to the reducer's pinion gear (i.e., planetary gear or drive gear). The pinion gear meshes with the yaw gear ring fixed to the tower. When the hydraulic motors rotate, they drive the pinion gear to revolve around the yaw gear ring via the reducer, thereby driving the nacelle (base) to yaw relative to the tower. The number of hydraulic motors disclosed is not specifically limited; for example, there can be 2 to 8 hydraulic motors, the specific number depending on the wind turbine size, yaw load (nacelle weight and wind load), required drive torque, and system redundancy design requirements.

[0033] Reference Figure 2The mechanical feedback mechanism 6 can be mechanically coupled to the hydraulic motors 7.1 and 7.2. For example, it can be a synchronous shaft, coupling, or a directly integrated structure. One end of the mechanical feedback mechanism 6 can be connected to the output shaft of the hydraulic motor 7.1 or the output end of the reducer, and the other end can be connected to the valve core adjustment mechanism of the digital servo valve 5. The valve core adjustment mechanism can be composed of a displacement sensor (such as a potentiometer or encoder) or a mechanical lever system, capable of detecting the actual output position or angle of the hydraulic motor in real time and converting it into a mechanical displacement signal that is transmitted to the digital servo valve 5.

[0034] The mechanical feedback mechanism 6 can be mechanically linked with the digital servo valve 5. As an example, the mechanical feedback mechanism 6 can be directly or indirectly connected to the valve core of the digital servo valve 5 via mechanical components such as linkages, sliders, or springs. The input end of the mechanical feedback mechanism 6 can be connected to the output shaft of a hydraulic motor, and the output end of the mechanical feedback mechanism can be coupled to the valve core of the digital servo valve 5.

[0035] When the hydraulic motor rotates, the mechanical feedback mechanism 6 generates a corresponding displacement, which pushes the valve core of the digital servo valve 5 to move, changing the valve opening, thereby adjusting the flow and direction of the hydraulic motor.

[0036] In addition, the digital servo valve 5 can also receive electrical signals from the controller 100 to drive the motor, thereby achieving active control of the valve core. Specifically, the controller 100 can generate control signals containing direction and speed / position commands based on wind direction signals and yaw targets, and output them to the motor of the digital servo valve 5. The motor drives the valve core of the digital servo valve 5 to perform active displacement adjustment, achieving precise control of hydraulic oil flow and direction. At the same time, the movement of the hydraulic motor is transmitted to the digital servo valve 5 in real time through the mechanical feedback mechanism 6, forming mechanical position feedback. Therefore, the digital servo valve 5 can be controlled by target commands provided by the controller 100. In addition, the digital servo valve 5 can also adjust the valve opening through mechanical feedback, automatically adjusting the valve opening when there is no power supply, thereby adjusting the yaw speed.

[0037] The mechanical feedback mechanism 6 can control the movement of the valve core of the digital servo valve in response to a yaw speed exceeding a first specified speed, thereby reducing the yaw speed. For example, when the wind speed changes abruptly or the actual yaw speed of the nacelle exceeds the first specified speed set by the controller, the rotational speed of the hydraulic motors 7.1 and 7.2 increases, driving the mechanical feedback mechanism 6, which is mechanically connected to them, to generate a displacement or force proportional to the rotational speed. This displacement or force acts in the opposite direction on the valve core of the digital servo valve 5 through a linkage, push rod, or cam mechanism, pushing the valve core to move in the direction of reducing the opening (e.g., moving towards the center position), thereby reducing the yaw speed and avoiding vibration, impact, or structural overload caused by excessive rotational speed.

[0038] Mechanical feedback mechanism 6 can control the movement of the valve core of the digital servo valve in response to a yaw speed lower than a second specified speed, thereby increasing the yaw speed, where the first specified speed is greater than or equal to the second specified speed. For example, when yaw resistance increases or driving force is insufficient, causing the yaw speed to fall below the second specified speed (e.g., the minimum speed required for effective wind resistance): the rotational speeds of hydraulic motors 7.1 and 7.2 decrease, and mechanical feedback mechanism 6 positively pushes the valve core of digital servo valve 5, causing it to move in the direction of increasing opening, thereby adjusting the yaw speed back to the normal range. Both the first and second specified speeds mentioned above can be set by the controller, and the first and second specified speeds can be equal.

[0039] Reference Figure 2 The mechanical feedback mechanism 6 can be integrally formed with the digital servo valve 5. As an example, an integrated digital hydraulic device with a mechanical feedback structure (including a hydraulic motor, a mechanical feedback mechanism, and a digital servo valve) can be used. However, the embodiments of this disclosure are not limited to this. The digital servo valve, hydraulic motor, and mechanical feedback mechanism can be installed independently and connected by pipelines and mechanical linkages, as long as they can achieve mechanical feedback to drive the valve core.

[0040] As an example, the mechanical feedback mechanism 6 can adopt various mechanical transmission forms such as levers, cams, displacement rods, and spring reset mechanisms, as long as it can convert the output motion (position / speed) of the hydraulic motor into the adjustment effect on the valve core.

[0041] Reference Figure 1 Hydraulic motors 7.1 and 7.2 may have a first inlet / outlet (upper inlet / outlet) and a second inlet / outlet (lower inlet / outlet). The specific installation methods of hydraulic motors 7.1 and 7.2 are as described above.

[0042] The digital servo valve 5 can be a three-position four-way valve; however, this is just an example. The digital servo valve 5 can have different numbers of "positions" and "ports." For example, the digital servo valve 5 can be a three-position five-way valve with a P port, a T port, and three other working ports (A port, B port, and C port). For example, it can use only its four working ports (P, T, A, and B) and close or not connect the fifth working port (such as C port), thus being functionally equivalent to a three-position four-way valve.

[0043] The first and second ports of the digital servo valve 5 can be connected to the second inlet / outlet port and the first inlet / outlet port, respectively. Taking a three-position four-way valve as an example, the first port (e.g., port B) and the second port (e.g., port A) of the digital servo valve 5 can be connected to the first inlet / outlet port (upper inlet / outlet port) and the second inlet / outlet port (lower inlet / outlet port) of the hydraulic motors 7.1 and 7.2, respectively.

[0044] Reference Figure 1Hydraulic drive modules 1 and 2 can be connected to the third port (e.g., P port) of digital servo valve 5 and supply hydraulic oil to the hydraulic motor via digital servo valve 5. Hydraulic oil collection module 16 (e.g., hydraulic oil tank) can be connected to the fourth port (e.g., T port) of digital servo valve 5.

[0045] Hydraulic drive modules 1 and 2 are the active power sources of the system, providing the hydraulic oil required for the hydraulic motors 7.1 and 7.2 to drive the engine room to rotate. Hydraulic drive modules 1 and 2 may include a hydraulic pump 2 and a motor 1 connected to the hydraulic pump.

[0046] In addition, the hydraulic yaw system disclosed herein may also include a first check valve 3.1 and a first relief valve 11, the first working port of the hydraulic pump 2 is connected to the hydraulic oil tank, the second working port of the hydraulic pump 2 is connected to the input port of the first check valve 3.1, the output port of the first check valve 3.1 is connected to a third port (e.g., port P) and can be connected to the hydraulic oil tank via the first relief valve 11.

[0047] As an example, the hydraulic yaw system disclosed herein may also include a normally open valve 4, the first port of which may be connected to a third port (e.g., port P), and the second port of which may be connected to a fourth port (e.g., port T).

[0048] As an example, normally open valve 4 can be a solenoid valve, which opens when no power is applied. Normally open valve 4 can be electrically controlled by a controller. Normally open valve 4 can be a two-position, two-way solenoid valve; however, this disclosure is not limited thereto. Normally open valve 4 can have different configurations of "position" and "way".

[0049] As an example, the first relief valve 11 can be used as a safety valve, with a fixed opening pressure set. It automatically opens when the system pressure exceeds the set value to prevent overload damage to components. The parallel connection of the normally open valve 4 and the first relief valve 11 can achieve controllable unloading. The normally open valve 4 can provide active control capability, while the first relief valve 11 can provide uncontrollable but reliable overpressure protection.

[0050] Although Figure 1 The hydraulic yaw system shown includes a normally open valve 4 and a first relief valve 11; however, this is merely an example. The hydraulic yaw system of this disclosure may also include various other auxiliary components disposed on the oil supply path of the hydraulic pump 2 and the oil return path of the hydraulic tank.

[0051] As an example, the hydraulic yaw system of this disclosure may further include a first pressure sensor 18.1 and a second pressure sensor 18.2, wherein the first pressure sensor 18.1 and the second pressure sensor 18.2 may be respectively installed at port A of hydraulic motors 7.1 and 7.2 (e.g., Figure 1 The hydraulic motor 7.1 shown below (the lower port) and port B (as shown) Figure 1The pressure sensor 18.1 can be installed at the upper port of the hydraulic motor 7.2 shown, or at ports A and B of the digital servo valve 5, respectively, to monitor the working pressure on both sides of the hydraulic motor in real time. The first pressure sensor 18.1 and the second pressure sensor 18.2 can feed back the pressure signal to the controller 100, enabling precise monitoring of yaw drive force, load status, and system malfunctions (such as jamming or overload). Combined with the mechanical feedback mechanism, it can help determine the matching between the actual motor speed and the load, improving control accuracy and safety.

[0052] In addition to the hydraulic oil tank, the hydraulic oil collection module 16 may include other auxiliary components. For example, the hydraulic oil collection module 16 may include a fan motor 12 and a radiator 13. The first working port of the fan motor 12 is connected to the fourth port (e.g., T port) of the digital servo valve 5 and the second oil port of the normally open valve 4. The first working port of the radiator 13 can be connected to the second working port of the fan motor 12, and the second working port of the radiator 13 can be connected to the hydraulic oil tank. As an example, a throttle valve 17 can be provided at the inlet of the normally open valve 4. The throttle valve 17 can also be replaced with a throttle orifice. As an example, the throttle valve 17 can be replaced with a proportional valve or a temperature-compensated valve, as long as it can operate stably in passive yaw mode without external power.

[0053] The second working port of the radiator 13 can be connected to the hydraulic oil tank via the filter device 15. The filter device 15 may include an indicator element (leftmost component), a filter replacement element (middle component), and a built-in bypass valve (rightmost component) that automatically opens when the filter element is clogged and causes excessive differential pressure. The built-in bypass valve prevents excessive back pressure of the return oil, and the indicator element can issue an alarm signal when clogging occurs.

[0054] A check valve or other components may also be installed between the filter device 15 and the hydraulic oil tank, such as... Figure 1 As shown, the second check valve 3.2 and the throttling element 9 (e.g., throttling orifice or throttling valve) form a parallel branch, which is connected between the filter device 15 and the hydraulic oil tank.

[0055] In addition, a second relief valve 14 is connected in parallel at the oil port of the fan motor 12. The second relief valve 14 is set with a certain opening pressure. When the oil port pressure of the fan motor 12 is higher than the pressure set by the second relief valve 14, the second relief valve 14 opens to overflow, thereby preventing the oil port pressure of the fan motor 12 from becoming too high. The hydraulic circuit under different working conditions of this disclosure will be described in detail below.

[0056] Figure 3 A schematic diagram of the yaw drive process oil circuit according to an embodiment of the present disclosure is shown. Figure 4 A schematic diagram of the hydraulic circuit is shown when the hydraulic motor speed is insufficient according to an embodiment of the present disclosure. Figure 5 A schematic diagram of the hydraulic circuit when the hydraulic motor overspeeds according to an embodiment of the present disclosure is shown.

[0057] Normal yaw conditions Reference Figure 3 When yawing to the right (driving force direction upward), motor 1 starts and drives hydraulic pump 2 to rotate. Hydraulic pump 2 draws oil from the oil tank, and the hydraulic oil passes through the first check valve 3.1. The normally open valve 4 is energized and closed, blocking the main return oil passage, so that the system pressure is built up quickly, and the high-pressure oil is guided to the P port of digital servo valve 5.

[0058] Upon receiving a control signal, the internal valve core of digital servo valve 5 is driven to rotate by the motor within the digital servo valve, switching the oil circuit state: port P is connected to port A, and port B is connected to port T. Consequently, high-pressure oil flows from port P through port A and enters the second inlet / outlet ports (lower inlet / outlet ports) of multiple hydraulic motors 7.1 and 7.2. The motor in the digital servo valve is independent of motor 1 in the hydraulic drive module.

[0059] The low-pressure oil from the hydraulic motor is discharged from its first inlet / outlet port, enters port B of the digital servo valve 5, and flows to port T through the already connected B-T channel. The return oil from port T flows back to the hydraulic oil tank after passing through the fan motor 12, radiator 13, filter device 15, and second check valve 3.2 in sequence.

[0060] This results in the following hydraulic circuit: hydraulic oil tank → hydraulic pump 2 → P port of digital servo valve 5 → A port of digital servo valve 5 → second inlet / outlet ports (lower inlet / outlet ports) of hydraulic motors 7.1 and 7.2 → first inlet / outlet ports (upper inlet / outlet ports) of hydraulic motors 7.1 and 7.2 → B port of digital servo valve 5 → T port of digital servo valve 5 → fan motor 12 → radiator 13 → filter device 15 → second check valve 3.2 → hydraulic oil tank. The above hydraulic circuit under normal operating conditions is merely an example. The hydraulic oil flowing out of the T port of the digital servo valve may flow into the hydraulic oil tank without passing through at least one of the fan motor, radiator 13, filter device 15, and second check valve 3.2. The fan motor, radiator 13, filter device 15, and second check valve 3.2 can be connected in series, but this is only an example; at least two of them can be connected in parallel.

[0061] Although not shown, during left yaw (driving force direction downward), the hydraulic path can be formed as follows: hydraulic tank → hydraulic pump 2 → P port of digital servo valve 5 → B port of digital servo valve 5 → first inlet / outlet (upper inlet / outlet) of hydraulic motors 7.1 and 7.2 → second inlet / outlet (lower inlet / outlet) of hydraulic motors 7.1 and 7.2 → A port of digital servo valve 5 → T port of digital servo valve 5 → fan motor 12 → radiator 13 → filter device 15 → second check valve 3.2 → hydraulic tank.

[0062] Hydraulic motor speed insufficient Reference Figure 4 When a sudden change in wind speed causes abnormally strong winds to act on the nacelle, and the external load torque exceeds the driving capacity of the hydraulic yaw system, hydraulic motors 7.1 and 7.2 will be dragged in the opposite direction (i.e., "reverse drag"). At this time, the actual rotation direction of the motor is opposite to the command direction, the second oil inlet / outlet (lower oil inlet / outlet) is compressed to become the high-pressure side, and the first oil inlet / outlet (upper oil inlet / outlet) becomes the low-pressure side.

[0063] Although the hydraulic motor is being reverse-driven, the hydraulic pump 2 continues to supply oil under the drive of the motor 1. The high-pressure oil flows to the P port of the digital servo valve 5, creating resistance to the reverse flow and thus suppressing the uncontrolled rotation of the engine room. The high-pressure oil supplied by the hydraulic pump hinders the reverse flow of high-pressure oil when the motor is being reverse-driven, causing the motor to return to the direction of active yaw.

[0064] The mechanical feedback mechanism 6 detects that the actual speed of the motor is much lower than the commanded speed set by the digital servo valve motor through the gear end, generating speed deviation feedback. This speed deviation feedback, through mechanical linkage, pushes the valve core of the digital servo valve 5 to move further in the direction of increasing the opening; if the reverse drag lasts for a long time, the valve core will be pushed to the maximum opening (i.e., making the P-A passage fully open), maximizing the flow and pressure entering the motor, thereby restoring the driving force in the active yaw direction.

[0065] At this time, the hydraulic oil path is: hydraulic oil tank → hydraulic pump 2 → first check valve 3.1 → P port of digital servo valve 5, thus blocking the hydraulic oil outflow from the second inlet and outlet ports. When the oil pressure exceeds a certain threshold, the pressure of the oil circuit of the second inlet and outlet ports of hydraulic pump 2 is higher than the set pressure of the first relief valve 11. The first relief valve 11 opens, and the system pressure will no longer continue to rise. When the first relief valve 11 opens, the hydraulic oil in the hydraulic oil tank can flow into the first inlet and outlet ports of hydraulic motors 7.1 and 7.2 through the throttling element 9, filter device 15, radiator 13, fan motor 12, T port, and B port (i.e., the oil replenishment path is: hydraulic oil tank → throttling element 9 → filter device 15 → radiator 13 → fan motor 12 → T port of digital servo valve 5 → B port of digital servo valve 5 → first inlet and outlet ports of hydraulic motors 7.1 and 7.2 (upper inlet and outlet ports).

[0066] Unlike conventional motor yaw systems, where the motor current increases significantly when overloaded, triggering a trip within seconds, the tripped motor cannot provide driving force, causing the yaw system to be dragged to a high speed, leading to component failure. However, the hydraulic yaw system of this disclosure maintains a constant high pressure through the first relief valve 11 even under continuous reverse dragging conditions, and provides damping and reverse braking force through continuous oil supply, effectively limiting the yaw speed, preventing component failure, and significantly improving safety and survivability in extreme wind conditions.

[0067] Although not shown, when the driving force is downward and the external force is upward, the first inlet and outlet ports of hydraulic motors 7.1 and 7.2 are on the high-pressure side, and their second inlet and outlet ports are on the low-pressure side. The P port of digital servo valve 5 is connected to the B port, and the A port is connected to the T port. The specific hydraulic circuit will not be described in detail here.

[0068] Hydraulic motor overspeed Reference Figure 5 When the wind turbine is subjected to abnormal external forces during yaw (such as strong gusts accelerating the nacelle, with both the driving force and the external force pointing upwards), causing the speeds of hydraulic motors 7.1 and 7.2 to exceed the set threshold, it enters an overspeed condition. At this time, the mechanical feedback mechanism 6 detects through the gear end that the actual motor speed is much higher than the commanded speed set by the digital servo valve motor, generates a speed deviation signal, and pushes the valve core of the digital servo valve 5 to move towards a smaller opening direction through mechanical linkage, thereby reducing the flow rate into the motor and suppressing further increase in speed.

[0069] When the mechanical feedback mechanism detects an overspeed condition, it pushes the valve core of the digital servo valve 5 to move towards the neutral position or a smaller opening, partially closing the P-A passage and limiting the oil supply flow. At the same time, the B-T passage remains open to ensure unobstructed oil return. If the overspeed lasts for a long time, the valve core will be pushed to the minimum opening, or even close to the neutral position, putting the hydraulic motor in a "throttling and speed limiting" state, relying only on a small amount of oil to maintain low-speed operation, preventing vibration, impact, or structural damage caused by excessive speed.

[0070] At this time, the first inlet and outlet ports of hydraulic motors 7.1 and 7.2 are on the high-pressure side. The hydraulic oil is supplied to the P port of digital servo valve 5 through the following path: hydraulic oil tank → hydraulic pump 2 → first check valve 3.1 → P port of digital servo valve 5. This provides resistance to prevent the hydraulic motors from overspeeding. If the pressure at the first inlet and outlet ports of hydraulic motors 7.1 and 7.2 is higher than the set pressure of the first relief valve 11, the first relief valve 11 opens, and the high-pressure oil flows to the hydraulic oil tank. The low-pressure side hydraulic oil flows into the second inlet and outlet ports of hydraulic motors 7.1 and 7.2 through the following path: hydraulic oil tank → throttling element 9 → filter device 15 → radiator 13 → fan motor 12 → T port of digital servo valve 5 → A port → second inlet and outlet ports of hydraulic motors 7.1 and 7.2.

[0071] Reference Figure 5When an abnormal external load force is in the same direction as the active yaw drive force, the speed of the hydraulic motor exceeds the rated speed of the active yaw drive supplied by the hydraulic pump. The speed feedback from the gear end of the digital servo valve 5 is greater than the drive speed of the digital servo valve motor, causing the valve opening to decrease. If the forward drag time is long, the valve core of the digital servo valve 5 can be reversed. At this time, ports B and P are connected, and the high-pressure oil flowing out of the hydraulic pump 2 will obstruct the hydraulic oil flowing out of the external load drive motor, preventing the yaw speed from exceeding the set speed. The speed of the hydraulic motor (i.e., the yaw speed) will decrease. Since the force generated by the wind is dynamically changing, the digital servo valve 5, through a mechanical feedback mechanism connected to the yaw gear ring, can dynamically adjust the valve opening size, thereby avoiding overspeed due to forward drag.

[0072] Figure 6 A schematic diagram of the hydraulic circuit under passive yaw conditions according to an embodiment of the present disclosure is shown; Figure 7 A schematic diagram of the hydraulic circuit under non-electric passive yaw conditions according to an embodiment of the present disclosure is shown; and Figure 8 A schematic diagram of the drive oil circuit of a brake according to an embodiment of the present disclosure is shown.

[0073] Passive yaw (electrically passive, pump can supply hydraulic oil) Reference Figure 6 When a wind turbine enters a passive yaw state under heavy wind load, the nacelle can rotate freely to counteract the wind. However, due to severe wind speed fluctuations, the yaw speed becomes unstable. To achieve stable speed control during passive yaw, this hydraulic system uses a digital servo valve 5 in conjunction with a mechanical feedback mechanism to dynamically adjust the resistance of hydraulic motors 7.1 and 7.2, thereby achieving adaptive control of the yaw speed.

[0074] In passive yaw mode, motor 1 starts and drives hydraulic pump 2 to run, but normally open valve 4 is not energized (i.e., it is energized but not supplied with power), and remains normally open, so that the high pressure oil circuit cannot build up high pressure. The system pressure is limited to a low level by the first relief valve 11, ensuring that only low pressure oil is supplied to the motor and avoiding overpressure damage.

[0075] At this time, the low-pressure oil output by the hydraulic pump 2 enters the P port of the digital servo valve 5 through the first check valve 3.1, and then flows into the second inlet and outlet ports of the hydraulic motors 7.1 and 7.2 through the A port.

[0076] When driven by external force, at digital servo valve 5, port B and port T are connected. Due to the instability of the external driving force generated by the wind, the motor rotation speed is unstable without control intervention. When the fan controller detects through the sensor that the yaw speed exceeds the normal speed limit, the opening of digital servo valve 5 can be adjusted, thereby adjusting the pressure in the oil circuit of the first inlet and outlet of the hydraulic motor, providing resistance to the hydraulic motor, and thus realizing passive yaw speed control, stabilizing the passive yaw speed.

[0077] When the wind load is too large, the yaw speed will be greater than or equal to the rated speed. The digital servo valve 5 will automatically reduce the valve opening and reduce the yaw speed. The specific process is similar to the forward and reverse towing of active yaw, so it will not be described in detail here.

[0078] When the wind load is too low, the yaw speed will be less than the rated speed. The digital servo valve 5 will automatically increase the valve opening to increase the yaw speed.

[0079] Passive yaw without power When a wind turbine generator completely loses power due to grid failure, control system power outage, or other reasons, it cannot perform active yaw control. The nacelle will remain at a fixed angle for an extended period, leading to wind deviation and causing severe vibrations under strong winds. In severe cases, this can cause tower resonance or even tower collapse. This disclosure provides a passive hydraulic damping system that can still achieve passive yaw and adaptive speed adjustment in the event of a power outage, ensuring the safety of the generator.

[0080] Reference Figure 7 In the absence of power, when the wind speed increases to a certain level, the wind force can directly drive the nacelle to rotate, which in turn drives the reducer and hydraulic motor to rotate via the yaw gear ring. Since there is no power supply, motor 1 does not operate, hydraulic pump 2 stops supplying oil, and normally open valve 4 remains open, with pressure maintained by the accumulator or residual pressure. At this time, the hydraulic motor rotates in the opposite direction under wind load, and its output shaft drives the valve core of digital servo valve 5 to open via a mechanical feedback mechanism, forming a hydraulic oil circuit.

[0081] Hydraulic oil flows from port B to port P, passing through the valve port of digital servo valve 5, creating throttling resistance. According to hydraulic principles, as wind speed increases, the hydraulic motor speed increases, the oil flow rate increases, and the flow velocity through the valve port increases, leading to a rise in pressure at port B. This generates greater back pressure resistance within the hydraulic motor. This resistance forms a dynamic balance with the wind load, automatically limiting the yaw speed and achieving adaptive adjustment where "the higher the wind speed, the greater the damping."

[0082] The response to the direction of the external force is the first direction (e.g.) Figure 7(As shown in the upward direction) and the hydraulic yaw system is in the non-electric passive yaw mode, forming a hydraulic oil circuit in sequence with the first inlet / outlet (upper inlet / outlet), the first port (e.g., port B), the third port (e.g., port P), the first port of the normally open valve 4, the second port of the normally open valve 4, the fourth port (e.g., port T), the second port (e.g., port A), and the second inlet / outlet (lower inlet / outlet).

[0083] Reference Figure 7 The hydraulic oil path is as follows: first inlet / outlet of hydraulic motor → B port of digital servo valve 5 → P port → normally open valve 4 → T port → A port → second inlet / outlet of hydraulic motor. Excess hydraulic oil in the system can flow into the hydraulic oil tank through fan motor 12 → radiator 13 → filter device 15 → second check valve 3.2.

[0084] Although not shown, when the direction of the external force is a second direction opposite to the first direction and the hydraulic yaw system is in the non-electric passive yaw mode, a hydraulic circuit can be formed in sequence with a second inlet / outlet port (lower inlet / outlet port), a second port (e.g., port A), a fourth port (e.g., port T), a second port of normally open valve 4, a first port of normally open valve 4, a third port (e.g., port P), a first port (e.g., port B), and a first inlet / outlet port (upper inlet / outlet port).

[0085] Under varying wind loads, the system generates different hydraulic damping effects through valve throttling, allowing the nacelle to slowly turn towards the leeward direction at a controllable speed. This ultimately achieves a nose-to-wind orientation, eliminating the frontal area, reducing wind load disturbances, effectively suppressing vibration and structural stress, preventing tower collapse accidents, and significantly improving the unit's safety and survivability under extreme operating conditions. The entire process requires no electrical intervention, relying entirely on a mechanical-hydraulic coupling mechanism, ensuring high reliability.

[0086] Brake drive Reference Figure 8 The hydraulic yaw system disclosed herein may further include brakes 16.1 and 16.2, which may be hydraulic disc brakes integrated with or associated with the hydraulic motor, or referred to as hydraulic holding brakes. When the brakes are not controlled by high-pressure hydraulic oil, they are in a braking state under the force of the spring, preventing the hydraulic motor and yaw system from rotating, thus serving as a brake on the yaw system. The construction of the brakes is not limited to this. The brakes may have a large cavity and a small cavity, and the brakes may extend and retract based on the pressure difference between the large and small cavities.

[0087] The hydraulic yaw system disclosed herein may further include a first shuttle valve 8.1 and a second shuttle valve 8.2. The first shuttle valve 8.1 and the second shuttle valve 8.2 are hydraulic components that do not require external control and automatically switch based on fluid pressure difference. The first shuttle valve 8.1 and the second shuttle valve 8.2 can automatically select the side with higher pressure in their two input oil circuits and conduct it to the output port, while closing the low-pressure side.

[0088] As an example, the first shuttle valve 8.1 may internally include a movable shuttle-shaped spool valve (or ball valve) located in a three-way cavity, connecting a first inlet A2, a second inlet A1, and a first outlet B1. When the pressure at the first inlet A2 is greater than the pressure at the second inlet A1, the shuttle is pushed towards the second inlet A1, closing the second inlet A1 and allowing the first inlet A2 to connect with the first outlet B1. When the pressure at the second inlet A1 is greater than the pressure at the first inlet A2, the shuttle is pushed towards the first inlet A2, closing the first inlet A2 and allowing the second inlet A1 to connect with the first outlet B1. Thus, only the side with the higher current pressure is always connected to the outlet, while the other side is sealed and isolated. The second shuttle valve 8.2 may have the same internal structure as the first shuttle valve.

[0089] The second shuttle valve 8.2 may have a third inlet port A4, a fourth inlet port A3, and a second outlet port B2. The first inlet port A2 and the second inlet port A1 are respectively connected to the first inlet / outlet port and the second inlet / outlet port of the hydraulic motor. The first outlet port B1 is connected to the third inlet port A4, the fourth inlet port A3 is connected to the third port (P port), and the second outlet port B2 is connected to the brake. As an example, the second outlet port B2 may be connected to the rodless chamber of the brake.

[0090] Reference Figure 8 When there is no power supply and the nacelle is passively yawed by wind, the external force drives the hydraulic motors to rotate, creating a high-pressure oil flow path. The specific oil path is as follows: the first inlet / outlet (upper port) of hydraulic motors 7.1 and 7.2 → port B of digital servo valve 5 → port P of digital servo valve 5 → normally open valve 4 → port T of digital servo valve 5 → port A → the second inlet / outlet of hydraulic motors 7.1 and 7.2. Furthermore, the high-pressure oil from the first inlet / outlet of hydraulic motors 7.1 and 7.2 flows sequentially through the first inlet / outlet A2 of the first shuttle valve 8.1 → the first output port B1 → the third inlet A4 of the second shuttle valve 8.2 → the second output port B2, and then into brakes 16.1 and 16.2.

[0091] In addition, the hydraulic yaw system disclosed herein may also include an accumulator 10, which can be connected to the second output port B2 of the second shuttle valve 8.2 and the brakes 16.1 and 16.2. The accumulator 10 can still provide a short-term high-pressure oil source when the system loses its power source (such as power failure or hydraulic pump stoppage), ensuring reliable release of the yaw brake and thus guaranteeing the safe implementation of the passive yaw function.

[0092] Although not shown, the accumulator 10 can be charged with high-pressure oil and store energy by the hydraulic pump 2 during normal operation. When the wind turbine enters a power-off state due to a power grid failure or control system power loss, the hydraulic pump stops working, and the pressure in the main oil circuit drops rapidly. At this time, if the yaw brake relies solely on the back pressure generated by the motor reverse drag to release the brake, it may not be able to release in time due to excessive initial resistance or insufficient wind speed, causing the nacelle to be "locked up" and unable to rotate with the wind, which may lead to vibration or even tower collapse. The accumulator 10 can immediately supply pre-stored high-pressure oil to the brakes 16.1 and 16.2 at the moment of power failure, forcibly releasing the spring brake force, allowing the brakes to actively release, and creating conditions for passive yaw.

[0093] Reference Figure 8 The hydraulic yaw system of this disclosure may further include a third pressure sensor 18.3, which may be installed on the oil circuit interface of the accumulator 10 or its branch, for real-time monitoring of the oil pressure in the accumulator 10. Additionally, the hydraulic yaw system of this disclosure may also include a throttle valve 17.4, which may be used to limit the flow rate to the third pressure sensor 18.3, making the pressure value of the third pressure sensor 18.3 smoother and more stable.

[0094] like Figure 2 The controller 100 shown may be part of the hydraulic yaw system disclosed herein, and the controller 100 may control various controllable components in the hydraulic yaw system (e.g., hydraulic pump, digital servo valve, various solenoid valves, etc.).

[0095] The hydraulic yaw system disclosed herein may also include other conventional or optional hydraulic and control components besides those shown in the accompanying drawings to further enhance system performance, safety, and intelligence. For example, a temperature sensor may be added to monitor oil temperature and prevent overheating; a level switch may be configured to detect abnormal oil levels in the tank; a pressure relay or safety valve may be introduced to provide multiple overpressure protections; an additional accumulator charging port may be provided for easy maintenance; and a remote communication module may be added to upload sensor data to the main control system, supporting condition monitoring and predictive maintenance, etc.

[0096] The hydraulic yaw system according to embodiments of the present disclosure can achieve passive yaw in the event of a power outage.

[0097] The hydraulic yaw system according to embodiments of the present disclosure can automatically adjust the yaw speed without the need for a controller.

[0098] The hydraulic yaw system according to the embodiments of this disclosure can avoid the risk of wind turbine tower collapse caused by vortex-induced vibration due to yaw not being in the wind direction, thus protecting the safety of the wind turbine.

[0099] The above description is merely a preferred embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any changes or substitutions that are easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A hydraulic yaw system, characterized in that, The hydraulic yaw system includes: A hydraulic motor having a first oil inlet / outlet and a second oil inlet / outlet; A digital servo valve, wherein the first port and the second port of the digital servo valve are respectively connected to the second inlet / outlet port and the first inlet / outlet port; A mechanical feedback mechanism, wherein the input end of the mechanical feedback mechanism is connected to the output shaft of the hydraulic motor, and the output end of the mechanical feedback mechanism is coupled to the valve core of the digital servo valve; A hydraulic drive module is connected to the third port of the digital servo valve and supplies hydraulic oil to the hydraulic motor via the digital servo valve; The hydraulic oil collection module is connected to the fourth port of the digital servo valve.

2. The hydraulic yaw system according to claim 1, characterized in that, The mechanical feedback mechanism controls the valve core movement of the digital servo valve in response to the yaw speed being greater than a first specified speed, so as to reduce the yaw speed. The spool movement of the digital servo valve is controlled in response to a yaw speed less than a second specified speed to increase the yaw speed, wherein the first specified speed is greater than or equal to the second specified speed.

3. The hydraulic yaw system according to claim 1, characterized in that, The hydraulic yaw system also includes: The first shuttle valve has a first oil inlet, a second oil inlet, and a first output port; and The second shuttle valve has a third oil inlet, a fourth oil inlet, and a second output port. The first oil inlet and the second oil inlet are respectively connected to the first oil inlet and the second oil outlet, the first output port is connected to the third oil inlet, the fourth oil inlet is connected to the third port, and the second output port is connected to the brake.

4. The hydraulic yaw system according to claim 3, characterized in that, The hydraulic yaw system also includes an accumulator connected to the second output port.

5. The hydraulic yaw system according to claim 1, characterized in that, The hydraulic yaw system also includes a normally open valve, the first port of which is connected to the third port, and the second port of which is connected to the fourth port.

6. The hydraulic yaw system according to claim 5, characterized in that, In response to an external force in the first direction and the hydraulic yaw system being in a non-electric passive yaw mode, the valve core of the digital servo valve is opened in conjunction with the mechanical feedback mechanism, thereby forming a hydraulic oil circuit consisting of the first inlet / outlet port, the first port, the third port, the first oil port, the second oil port, the fourth port, the second port, and the second inlet / outlet port. In response to an external force in a second direction opposite to the first direction and the hydraulic yaw system being in a non-electric passive yaw mode, the valve core of the digital servo valve opens in conjunction with the mechanical feedback mechanism, sequentially forming a hydraulic oil circuit consisting of the second inlet / outlet port, the second port, the fourth port, the second oil port, the first oil port, the third port, the first port, and the first inlet / outlet port.

7. The hydraulic yaw system according to claim 6, characterized in that, The digital servo valve is a three-position four-way digital servo valve, with the first port, the second port, the third port, and the fourth port being port B, port A, port P, and port T, respectively.

8. The hydraulic yaw system according to claim 6, characterized in that, The hydraulic oil collection module includes: A fan motor, wherein the first working port of the fan motor is connected to the fourth port and the second oil port; A radiator, wherein the second working port of the fan motor is connected to the first working port of the radiator; The oil tank, the second working port of the radiator is connected to the oil tank.

9. The hydraulic yaw system according to claim 8, characterized in that, The hydraulic drive module includes a motor and a hydraulic pump connected to the motor. The hydraulic yaw system also includes a first check valve and a first relief valve. The first working port of the hydraulic pump is connected to the oil tank. The second working port of the hydraulic pump is connected to the input port of the first check valve. The output port of the first check valve is connected to the third port and connected to the oil tank via the first relief valve.

10. A wind turbine generator set, characterized in that, The wind turbine generator set includes a hydraulic yaw system according to any one of claims 1 to 9.

Images