Hybrid Servo System

Abstract

To easily implement accurate operation of a guide vane of a water turbine.SOLUTION: A bidirectional auxiliary pump is installed in parallel with a bidirectional control pump, supplies hydraulic oil to a first hydraulic chamber through a closing-side solenoid valve and a closing-side pilot valve in sequence, and supplies hydraulic oil to a second hydraulic chamber through an opening-side solenoid valve and an opening-side pilot valve in sequence. An accumulator stores the hydraulic oil supplied from an oil collection tank through an oil collection tank outlet solenoid valve, the bidirectional auxiliary pump, and a pressure accumulation solenoid valve in sequence. When executing pressure accumulation operation to store the hydraulic oil in the accumulator, a control unit changes the oil collection tank outlet solenoid valve and the pressure accumulation solenoid valve from a closed state to an open state while closing the closing-side solenoid valve and the opening-side solenoid valve, so that the bidirectional auxiliary pump sucks up the hydraulic oil from the oil collection tank via the oil collection tank outlet solenoid valve, and the hydraulic oil is supplied to the accumulator via the pressure accumulation solenoid valve.SELECTED DRAWING: Figure 3C

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to a hybrid servo system. [Background technology]

[0002] In a hydroelectric power plant, the opening and closing operation of guide vanes of a water turbine is controlled by, for example, a hydraulic servo motor driven by a hybrid servo system, which includes a hydraulic circuit having a bidirectional pump for driving the hydraulic servo motor.

[0003] To expand the scope of application of hybrid servo systems, efforts have been made to increase the capacity of bidirectional pumps, for example. However, there are cases where increasing the capacity of a bidirectional pump is not sufficient. For this reason, proposals have been made to connect multiple bidirectional pumps in parallel or to use an accumulator as an emergency stop device in addition to the bidirectional pump. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6298207 [Patent Document 2] Patent No. 6139041 Summary of the Invention [Problem to be solved by the invention]

[0005] In a hybrid servo system, an accumulator is installed to fully close the guide vanes in the event of a power outage, for example, and it is necessary to maintain a constant hydraulic pressure in the accumulator. Therefore, when the hydraulic pressure in the accumulator drops due to a hydraulic oil leak in the hydraulic circuit, the accumulator stores hydraulic oil to restore the hydraulic pressure. However, in conventional systems, it is difficult to store hydraulic oil in the accumulator while the turbine is operating, making it difficult to maintain a constant hydraulic pressure in the accumulator.

[0006] Due to the above circumstances, it may be difficult for the conventional hybrid servo system to accurately operate the guide vanes of the water turbine.

[0007] Therefore, an object of the present invention is to provide a hybrid servo system that can easily realize accurate operation of the guide vanes of a water turbine. [Means for solving the problem]

[0008] The hybrid servo system of one embodiment includes a hydraulic circuit unit that drives a hydraulic servomotor for performing opening and closing operations on guide vanes of a water turbine, and a control unit that controls the operation of the hydraulic circuit unit. The hydraulic servomotor has a piston attached to an operating rod that operates the guide vanes, and a cylinder that houses the piston in an internal space, the internal space being divided by the piston into a first hydraulic chamber and a second hydraulic chamber. The hydraulic circuit unit includes a bidirectional control pump, a bidirectional auxiliary pump, and an accumulator. The bidirectional control pump is configured to supply hydraulic oil to the first hydraulic chamber via a closing-side pilot valve when performing a closing operation, and to supply hydraulic oil to the second hydraulic chamber via an opening-side pilot valve when performing an opening operation. The bidirectional auxiliary pump is installed in parallel with the bidirectional control pump, and is configured to supply hydraulic oil to the first hydraulic chamber via a closing-side solenoid valve and a closing-side pilot valve in that order, and to supply hydraulic oil to the second hydraulic chamber via an opening-side solenoid valve and a opening-side pilot valve in that order. The accumulator is configured to store hydraulic oil supplied from an oil collection tank via an oil collection tank outlet solenoid valve, a bidirectional auxiliary pump, and an accumulating solenoid valve in this order. When performing an accumulating operation to store hydraulic oil in the accumulator, the control unit switches the oil collection tank outlet solenoid valve and the accumulating solenoid valve from a closed state to an open state while keeping the closing-side solenoid valve and the opening-side solenoid valve closed, and performs control so that the bidirectional auxiliary pump draws up hydraulic oil from the oil collection tank via the oil collection tank outlet solenoid valve, and the hydraulic oil drawn up by the bidirectional auxiliary pump is supplied to the accumulator via the accumulating solenoid valve. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a partial cross-sectional view schematically showing an example of a water turbine 90 in the first embodiment. [Figure 2] FIG. 2 is a diagram schematically showing the hydraulic servo motor 50 and hybrid servo system for performing opening and closing operations on the guide vanes 95 of the water turbine 90 (see FIG. 1) in the first embodiment. [Figure 3A]FIG. 3A is a diagram schematically showing a state in which the guide vane 95 performs a closing operation in the hybrid servo system of the first embodiment. [Figure 3B] FIG. 3B is a diagram that schematically shows a state in which the guide vane 95 performs an opening operation in the hybrid servo system of the first embodiment. [Figure 3C] FIG. 3C is a diagram that schematically shows a state when a pressure accumulation operation for accumulating hydraulic oil in the accumulator 140 is performed in the hybrid servo system of the first embodiment. [Figure 3D] FIG. 3D is a diagram schematically showing a state in which a failure occurs in the bidirectional control pump 110 and the guide vane 95 performs a closing operation in the hybrid servo system of the first embodiment. [Figure 3E] FIG. 3E is a diagram schematically showing a state in which a failure occurs in the bidirectional auxiliary pump 121 and the guide vane 95 performs a closing operation in the hybrid servo system of the first embodiment. [Figure 3F] FIG. 3F is a diagram that schematically shows a state in which the guide vane 95 performs a sudden closing operation in the hybrid servo system of the first embodiment. [Figure 3G] FIG. 3G is a diagram that schematically shows a state in which the hybrid servo system of the first embodiment performs a closing operation to close the guide vanes 95 in the event of a power outage. [Figure 4] FIG. 4 is a diagram schematically showing the hydraulic servo motor 50 and hybrid servo system for performing opening and closing operations on the guide vanes 95 of the water turbine 90 (see FIG. 1) in the second embodiment. [Figure 5A] FIG. 5A is a diagram schematically showing a state in which the guide vane 95 performs a closing operation in the hybrid servo system of the second embodiment. [Figure 5B] FIG. 5B is a diagram schematically showing a state in which the guide vane 95 performs an opening operation in the hybrid servo system of the second embodiment. [Figure 5C]FIG. 5C is a diagram schematically showing a state in which a pressure accumulation operation is performed to accumulate hydraulic oil in the accumulator 140 using the bidirectional auxiliary pump 121A in the hybrid servo system of the second embodiment. [Figure 5D] FIG. 5D is a diagram schematically showing a state in which a pressure accumulation operation is performed to accumulate hydraulic oil in the accumulator 140 using the bidirectional auxiliary pump 121B in the hybrid servo system of the second embodiment. [Figure 5E] FIG. 5E is a diagram schematically showing a state in which a failure occurs in the bidirectional control pump 110 and the guide vane 95 performs a closing operation in the hybrid servo system of the second embodiment. [Figure 5F] FIG. 5F is a diagram schematically showing a state in which a failure occurs in the bidirectional auxiliary pump 121A and the bidirectional auxiliary pump 121B in the hybrid servo system of the second embodiment, causing the guide vane 95 to perform a closing operation. [Figure 5G] FIG. 5G is a diagram that schematically shows a state in which the guide vane 95 performs a sudden closing operation in the hybrid servo system of the second embodiment. [Figure 5H] FIG. 5H is a diagram that schematically shows a state in which the hybrid servo system of the second embodiment performs a closing operation to close the guide vanes 95 in the event of a power outage. DETAILED DESCRIPTION OF THE INVENTION

[0010] First Embodiment [A] Configuration of Waterwheel 90 Fig. 1 is a partial cross-sectional view schematically showing an example of a water turbine 90 in the first embodiment. Fig. 1 shows a longitudinal cross section (a plane including the center of rotation).

[0011] The water turbine 90 is a Francis type water turbine, and as shown in FIG. 1, has a runner 91, a main shaft 92, an upper cover 93, a lower cover 94, guide vanes 95, a casing 96, a discharge pipe 97 (draft pipe), and a generator 98.

[0012] [A-1] Runner 91 In the water turbine 90, the runner 91 has a runner crown 911, a runner band 912, and runner vanes 913, and is configured to rotate together with the main shaft 92. The runner 91 has the runner crown 911 and the runner band 912 arranged with a gap between them. In the runner 91, a plurality of runner vanes 913 are provided between the runner crown 911 and the runner band 912.

[0013] [A-2] Main shaft 92 The main shaft 92 has a longitudinal direction aligned with the vertical direction, and the lower end of the main shaft 92 is connected to the upper surface of a runner crown 911 that constitutes the runner 91.

[0014] [A-3] Top cover 93 The upper cover 93 is provided above the runner 91. The main shaft 92 passes through the center of the upper cover 93, and the upper cover 93 covers the upper surface of the runner crown 911 on the side of the outer circumferential surface of the main shaft 92.

[0015] [A-4] Lower cover 94 The lower cover 94 is provided below the runner 91. The discharge pipe 97 is provided below the lower cover 94, and the outer periphery of the discharge pipe 97 covers the lower surface of the runner band 912.

[0016] [A-5] Guide Vane 95 The guide vanes 95 are installed on the outer periphery of the runner 91 and are connected to the outer surfaces of the upper cover 93 and the lower cover 94. The guide vanes 95 adjust the flow rate of water flowing into the runner 91 by changing the opening degree.

[0017] [A-6] Casing 96 The casing 96 has a doughnut shape and is disposed on the outer periphery of the guide vane 95 .

[0018] [A-7] Discharge pipe 97 The discharge pipe 97 is provided below the runner 91 and connected to the lower cover 94 .

[0019] [A-8] Generator 98 The generator 98 is connected to the upper side of the main shaft 92. The generator 98 is configured to generate electricity when the main shaft 92 is rotated.

[0020] During power generation operation, water flows from the outer periphery (side) of the runner 91 to the inside of the water turbine 90 via the casing 96 and the guide vanes 95. This causes the runner 91 to rotate around the main shaft 92. The rotation of the main shaft 92 drives the generator 98.

[0021] During power generation operation, water flows in from the outer periphery of the runner 91 , flows between the runner crown 911 and the runner band 912 in the runner 91 , then flows from above to below, and is discharged to the discharge pipe 97 .

[0022] [B] Hydraulic servo motor 50 and hybrid servo system configuration 2 is a diagram schematically illustrating the hydraulic servo motor 50 and hybrid servo system for opening and closing the guide vanes 95 of the water turbine 90 (see FIG. 1) in the first embodiment. In FIG. 2, whether the state of the solenoid valve is in the energized state EG or the deenergized state DG is also indicated.

[0023] [B-1] Hydraulic servo motor 50 2, the hydraulic servomotor 50 includes an operating rod 51, a cylinder 52, and a piston 55. In the hydraulic servomotor 50, the operating rod 51 for operating the guide vane 95 is provided with the piston 55, and the piston 55 is housed in the cylinder 52. The hydraulic servomotor 50 is configured such that the operating rod 51 operates the guide vane 95 by driving the piston 55 inside the cylinder 52 by the action of hydraulic oil.

[0024] [B-1-1] Operating rod 51 Specifically, the operating rod 51 is a rod-shaped body, one end of which is connected to the guide vane 95 and the other end of which is connected to the piston 55 .

[0025] [B-1-2] Cylinder 52 The cylinder 52 accommodates a piston 55 in an internal space C52. The internal space C52 of the cylinder 52 is divided by the piston into a first hydraulic chamber C52a and a second hydraulic chamber C52b.

[0026] In the cylinder 52, the first hydraulic chamber C52a is provided with a first hydraulic oil port P52a, and the second hydraulic chamber C52b is provided with a second hydraulic oil port P52b.

[0027] [B-1-3] Piston 55 The piston 55 is connected to the operating rod 51 in the internal space C52 of the cylinder 52. The piston 55 is configured to slide in the internal space C52 of the cylinder 52 in accordance with the pressure difference of the hydraulic oil between the first hydraulic chamber C52a and the second hydraulic chamber C52b.

[0028] Specifically, when performing a closing operation of the guide vane 95, the piston 55 slides from the first hydraulic chamber C52a side to the second hydraulic chamber C52b side. When performing an opening operation of the guide vane 95, the piston 55 slides from the second hydraulic chamber C52b side to the first hydraulic chamber C52a side.

[0029] [B-1-4] Displacement detection unit 500 The hydraulic servo motor 50 is further provided with a displacement detection unit 500. The displacement detection unit 500 is provided to detect the amount by which the opening degree of the guide vanes 95 is displaced.

[0030] [B-2] Hybrid Servo System 2, the hybrid servo system includes a hydraulic circuit unit 100 and a control unit 800. The hybrid servo system of this embodiment is configured such that the control unit 800 controls the operation of the hydraulic circuit unit 100 to drive the hydraulic servo motor 50, causing the hydraulic servo motor 50 to perform opening and closing operations on the guide vanes 95.

[0031] [B-2-1] Hydraulic circuit section 100 In the hybrid servo system, the hydraulic circuit section 100 includes a bidirectional control pump 110, a bidirectional auxiliary pump 121, an oil collection tank 130, and an accumulator 140. The hydraulic circuit section 100 also includes a closing solenoid valve V121a, an opening solenoid valve V121b, a closing pilot valve V30a, an opening pilot valve V30b, an oil collection tank outlet solenoid valve V21, an accumulator solenoid valve V22, an accumulator oil supply pilot check valve V33, and an accumulator oil supply solenoid valve V35.

[0032] In addition, the hydraulic circuit section 100 is provided with a closing pilot check valve V15a, an opening pilot check valve V15b, a closing relief valve V16a, an opening relief valve V16b, a closing check valve V18a, and an opening check valve V18b.The hydraulic circuit section 100 is further provided with a gate valve SV17, a gate valve SV21, a gate valve SV22a, a closing gate valve SV22b, a gate valve SV32, a pressure switch SW22, a pressure switch SW34, and a pressure switch SW35.

[0033] The individual components of the hydraulic circuit unit 100 are configured so that hydraulic oil flows through oil passages L11 to L18, L11c, L12c, L17a, L21 to L26, and L31 to L38.

[0034] Each part constituting the hydraulic circuit section 100 will be explained in order.

[0035] [B-2-1-1] Bidirectional control pump 110 The bidirectional control pump 110 is, for example, a reversible rotary pump, and has a port a (first bidirectional control pump port) and a port b (second bidirectional control pump port). The bidirectional control pump 110 is configured to discharge hydraulic oil from each of the ports a and b.

[0036] [B-2-1-2] Bidirectional auxiliary pump 121 The bidirectional auxiliary pump 121 is, for example, a reversible rotary pump similar to the bidirectional control pump 110, and has a port a (first bidirectional auxiliary pump port) and a port b (second bidirectional auxiliary pump port). The bidirectional auxiliary pump 121 is configured to discharge hydraulic oil from each of the ports a and b.

[0037] The bidirectional auxiliary pump 121 is installed in parallel with the bidirectional control pump 110. Here, port a of the bidirectional auxiliary pump 121 is configured to supply hydraulic oil to the first hydraulic chamber C52a upstream of port a of the bidirectional control pump 110, and port b of the bidirectional auxiliary pump 121 is configured to supply hydraulic oil to the second hydraulic chamber C52b upstream of port b of the bidirectional control pump 110.

[0038] [B-2-1-3] Oil collection tank 130 The oil collection tank 130 is, for example, a tank configured to store hydraulic oil.

[0039] [B-2-1-4] Accumulator 140 The accumulator 140 is configured to store and release hydraulic fluid in response to the pressure of a pressurized gas such as nitrogen.

[0040] Although details will be described later, the hydraulic oil stored in the accumulator 140 is released to fully close the guide vanes 95 in the event of, for example, a power outage (loss of power supply). The accumulator 140 is configured so that hydraulic oil is supplied from the oil collection tank 130 by the operation of the bidirectional auxiliary pump 121.

[0041] [B-2-1-5] Oil passage L11 One end of the oil passage L11 is connected to port a of the bidirectional auxiliary pump 121, and the other end is configured to communicate with the first hydraulic oil port P52a of the cylinder 52. The oil passage L11 is provided with a branch portion J11a, a branch portion J11b, a branch portion J11c, a branch portion J11d, a branch portion J11e, and a branch portion J11f, which are arranged in this order from the bidirectional auxiliary pump 121 side toward the cylinder 52 side.

[0042] [B-2-1-6] Closing solenoid valve V121a In the oil passage L11, a closing solenoid valve V121a is provided between the branching portion J11a and the branching portion J11b. The closing solenoid valve V121a is, for example, a two-port two-position directional control valve, and includes a port 1 and a port 2.

[0043] In this embodiment, the closing solenoid valve V121a is a normally open type. That is, when the closing solenoid valve V121a is in the energized state EG, the communication between port 1 and port 2 is blocked (closed state), and the oil passage L11 is closed. When the closing solenoid valve V121a is in the deenergized state DG, the communication between port 1 and port 2 is established (open state), and the oil passage L11 is opened.

[0044] [B-2-1-7] Close side pilot valve V30a A closing pilot valve V30a is provided in oil passage L11 at a portion closer to cylinder 52 than branch point J11f. The closing pilot valve V30a is, for example, a 4-port 2-position directional control valve and includes ports 1, 2, 3, and 4.

[0045] In this embodiment, the closing pilot valve V30a is configured to switch between a state in which ports 1 and 2 and ports 3 and 4 are communicated and a state in which ports 1 and 4 and ports 2 and 3 are communicated, depending on the pressure difference of the hydraulic oil applied to the pilot port. As will be described in detail later, when the accumulator oil supply solenoid valve V35 changes from the energized state EG to the de-energized state DG, the closing pilot valve V30a switches when hydraulic oil acts on the pilot port via the oil passage L36 and the like, and a state in which ports 1 and 4 and ports 2 and 3 are communicated.

[0046] [B-2-1-8] Oil passage L12 One end of the oil passage L12 is connected to port b of the bidirectional auxiliary pump 121, and the other end is configured to communicate with the second hydraulic oil port P52b of the cylinder 52. The oil passage L12 is provided with a branch portion J12a, a branch portion J12b, a branch portion J12c, a branch portion J12d, a branch portion J12e, and a branch portion J12f, which are arranged in this order from the bidirectional auxiliary pump 121 side toward the cylinder 52 side.

[0047] [B-2-1-9] Opening side solenoid valve V121b An opening solenoid valve V121b is provided in the oil passage L12 between the branching point J12a and the branching point J12b. The opening solenoid valve V121b is, for example, a two-port two-position directional control valve, and includes a port 1 and a port 2.

[0048] In this embodiment, the opening-side solenoid valve V121b is a normally open type. That is, when the opening-side solenoid valve V121b is in the energized state EG, the communication between port 1 and port 2 is blocked and the oil passage L12 is closed. When the opening-side solenoid valve V121b is in the deenergized state DG, the communication between port 1 and port 2 is established and the oil passage L12 is opened.

[0049] [B-2-1-10] Opening side pilot valve V30b An opening-side pilot valve V30b is provided in the oil passage L12 at a portion closer to the cylinder 52 than the branch point J12f. The opening-side pilot valve V30b is, for example, a 4-port 2-position directional control valve and includes a port 1, a port 2, a port 3, and a port 4.

[0050] In this embodiment, the opening-side pilot valve V30b is configured to switch between a state in which ports 1 and 2 and ports 3 and 4 are communicated and a state in which ports 1 and 4 and ports 2 and 3 are communicated, depending on the pressure difference of the hydraulic oil applied to the pilot port. As will be described in detail later, when the accumulator oil supply solenoid valve V35 changes from the energized state EG to the de-energized state DG, hydraulic oil acts on the pilot port via the oil passage L37 and the like, and a state in which ports 1 and 4 and ports 2 and 3 are communicated is switched over when the opening-side pilot valve V30b changes from the energized state EG to the de-energized state DG.

[0051] [B-2-1-11] Oil passage L13, oil passage L14, oil passage L15 One end of the oil passage L13 is connected to port a of the bidirectional control pump 110, and the other end is connected to the branch point J11b of the oil passage L11. One end of the oil passage L14 is connected to port b of the bidirectional control pump 110, and the other end is connected to the branch point J12b of the oil passage L12. One end of the oil passage L15 is connected to the branch point J11d of the oil passage L11, and the other end is connected to the branch point J12d of the oil passage L12. The oil passage L15 is provided with a branch point J15.

[0052] [B-2-1-12] Close side pilot check valve V15a A close-side pilot check valve V15a is provided in oil passage L15 between branch J11d and branch J15. The close-side pilot check valve V15a has an IN port on the branch J15 side and an OUT port on the branch J11d side, and when the pressure of hydraulic oil applied to the pilot port is equal to or lower than a set value, hydraulic oil flows from the IN port to the OUT port. When the pressure of hydraulic oil applied to the pilot port exceeds the set value, the close-side pilot check valve V15a is configured to allow hydraulic oil to flow back from the OUT port to the IN port.

[0053] [B-2-1-13] Opening side pilot check valve V15b An opening pilot check valve V15b is provided in oil passage L15 between branch J12d and branch J15. The opening pilot check valve V15b has an IN port on the branch J15 side and an OUT port on the branch J12d side, and when the pressure of hydraulic oil applied to the pilot port is equal to or lower than a set value, hydraulic oil flows from the IN port to the OUT port. When the pressure of hydraulic oil applied to the pilot port exceeds the set value, the opening pilot check valve V15b is configured to allow hydraulic oil to flow back from the OUT port to the IN port.

[0054] [B-2-1-14] Oil passage L16 One end of the oil passage L16 is connected to a branch point J11e of the oil passage L11, and the other end is connected to a branch point J12e of the oil passage L12. The oil passage L16 is provided with a branch point J16.

[0055] [B-2-1-15] Closing side relief valve V16a A closing relief valve V16a is provided in the oil passage L16 between the branch J11e and the branch J16. The closing relief valve V16a is configured to open when the pressure of the hydraulic oil exceeds a set value.

[0056] [B-2-1-16] Opening side relief valve V16b An opening relief valve V16b is provided in the oil passage L16 between the branch point J12e and the branch point J16. The opening relief valve V16b is configured to open when the pressure of the hydraulic oil exceeds a set value.

[0057] [B-2-1-17] Oil passage L17 One end of the oil passage L17 is connected to a branch point J15 of the oil passage L15, and the other end is connected to the oil collection tank 130. The oil passage L17 is provided with a branch point J17.

[0058] [B-2-1-18] Gate valve SV17 A gate valve SV17 is provided in the oil passage L17 at a portion located closer to the oil collection tank 130 than the branch point J17.

[0059] [B-2-1-19] Oil passage L18 One end of the oil passage L18 is connected to a branch point J11f of the oil passage L11, and the other end is connected to a branch point J12f of the oil passage L12. The oil passage L18 is provided with a branch point J18.

[0060] [B-2-1-20] Close side check valve V18a A closing check valve V18a is provided in oil passage L18 between branch J11f and branch J18. The closing check valve V18a has an IN port on the branch J18 side and an OUT port on the branch J11f side, and is configured so that hydraulic oil flows from the IN port to the OUT port but does not flow from the OUT port to the IN port.

[0061] [B-2-1-21] Opening check valve V18b An opening check valve V18b is provided in oil passage L18 between branch J12f and branch J18. The opening check valve V18b has an IN port on the branch J18 side and an OUT port on the branch J12f side, and is configured so that hydraulic oil flows from the IN port to the OUT port but does not flow from the OUT port to the IN port.

[0062] [B-2-1-22] Oil path L11c, oil path L12c, oil path L17a, oil path L21 One end of oil passage L11c is connected to a branch J11c of oil passage L11, and the other end is connected to a pilot port of opening pilot check valve V15b. One end of oil passage L12c is connected to a branch J12c of oil passage L12, and the other end is connected to a pilot port of closing pilot check valve V15a. One end of oil passage L17a is connected to a branch J17 of oil passage L17, and the other end is connected to a branch J18 of oil passage L18. One end of oil passage L21 is connected to a branch J11a of oil passage L11, and the other end is connected to oil collection tank 130.

[0063] [B-2-1-23] Oil collection tank outlet solenoid valve V21 An oil collection tank outlet solenoid valve V21 is provided in the oil passage L21. The oil collection tank outlet solenoid valve V21 is, for example, a two-port two-position directional control valve, and includes a port 1 and a port 2.

[0064] In this embodiment, the oil collection tank outlet solenoid valve V21 is of a normally closed type. That is, when the oil collection tank outlet solenoid valve V21 is in the demagnetized state DG, the communication between port 1 and port 2 is blocked, and the oil passage L21 is closed. When the oil collection tank outlet solenoid valve V21 is in the magnetized state EG, the communication between port 1 and port 2 is established, and the oil passage L21 is opened.

[0065] [B-2-1-24] Gate valve SV21 In the oil passage L21, a gate valve SV21 is provided at a portion located closer to the oil collection tank 130 than the oil collection tank outlet solenoid valve V21.

[0066] [B-2-1-25] Oil passage L22 One end of the oil passage L22 is connected to a branch point J12a of the oil passage L12. A pressure switch SW22 and a shut-off valve SV22b are provided at the other end J22b of the oil passage L22. The oil passage L22 is further provided with a branch point J22a between the one end and the other end J22b.

[0067] [B-2-1-26] Accumulator solenoid valve V22 In the oil passage L22, between the branching point J12a and the branching point J22a, there is provided a pressure-accumulating solenoid valve V22. The pressure-accumulating solenoid valve V22 is, for example, a two-port two-position directional control valve, and includes a port 1 and a port 2.

[0068] In this embodiment, the pressure-accumulating solenoid valve V22 is a normally closed type. That is, when the pressure-accumulating solenoid valve V22 is in the demagnetized state DG, the communication between port 1 and port 2 is blocked, and the oil passage L22 is closed. When the pressure-accumulating solenoid valve V22 is in the energized state EG, the communication between port 1 and port 2 is established, and the oil passage L22 is opened.

[0069] [B-2-1-27] Gate valve SV22a In the oil passage L22, a gate valve SV22a is installed between the branch point J22a and the other end J22b.

[0070] [B-2-1-28] Oil path L23, oil path L24, oil path L25, oil path L26 One end of oil passage L23 is connected to branch point J16 of oil passage L16, and the other end is connected to oil collection tank 130. One end of oil passage L24 is connected to port 3 of opening pilot valve V30b, and the other end is connected to oil collection tank 130. One end of oil passage L25 is connected to port 4 of closing pilot valve V30a, and the other end is connected to oil collection tank 130. Branch points J25a and J25b are provided in this order in oil passage L25, from the oil collection tank 130 side toward the closing pilot valve V30a side. One end of oil passage L26 is connected to port 4 of opening pilot valve V30b, and the other end is connected to branch point J25b of oil passage L25.

[0071] [B-2-1-29] Oil passage L31, oil passage L32 One end of the oil passage L31 is connected to the accumulator 140, and the other end is connected to the branch point J22a of the oil passage L22. One end of the oil passage L32 is connected to the branch point J22a of the oil passage L22, and the other end is connected to the stored-oil supply solenoid valve V35.

[0072] [B-2-1-30] Pressure storage oil supply solenoid valve V35 The stored oil supply solenoid valve V35 is, for example, a 4-port 2-position directional control valve that includes ports 1, 2, 3, and 4, and the other end of the oil passage L32 is configured to be connected to port 2 of the stored oil supply solenoid valve V35.

[0073] In this embodiment, the accumulator oil supply solenoid valve V35 is configured so that, in the demagnetized state DG, communication is established between port 1 and port 2, and between port 3 and port 4. The accumulator oil supply solenoid valve V35 is configured so that, in the energized state EG, communication is established between port 1 and port 4, and between port 2 and port 3.

[0074] [B-2-1-31] ​​Gate valve SV32 The oil passage L32 is provided with a branching portion J32. A gate valve SV32 is provided in a portion of the oil passage L32 that is closer to the branching portion J22a than the branching portion J32.

[0075] [B-2-1-32] Oil passage L33 One end of the oil passage L33 is connected to a branch point J32 of the oil passage L32, and the other end is connected to port 3 of the closing pilot valve V30a.

[0076] [B-2-1-33] Pilot check valve for storage oil supply V33 An accumulator oil supply pilot check valve V33 is installed in oil passage L33. The accumulator oil supply pilot check valve V33 has an IN port on the closing pilot valve V30a side and an OUT port on the branch J32 side, and when the pressure of hydraulic oil applied to the pilot port is equal to or lower than a set value, hydraulic oil flows from the IN port to the OUT port. The accumulator oil supply pilot check valve V33 is configured so that when the pressure of hydraulic oil applied to the pilot port exceeds the set value, hydraulic oil flows back from the OUT port to the IN port.

[0077] [B-2-1-34] Oil passage L34, oil passage L35 One end of the oil passage L34 is connected to port 1 of the accumulator oil supply solenoid valve V35. A pressure switch SW34 is provided in the oil passage L34. One end of the oil passage L35 is connected to port 3 of the accumulator oil supply solenoid valve V35, and the other end is closed. A pressure switch SW35 is provided in the oil passage L35.

[0078] [B-2-1-35] Oil passage L36, oil passage L37, oil passage L38 One end of the oil passage L36 is connected to the pilot port of the accumulator-oil supply pilot check valve V33, and the other end is connected to the pilot port of the closing pilot valve V30a. Branches J36a and J36b are provided in the oil passage L36, in that order, from the accumulator-oil supply pilot check valve V33 side toward the closing pilot valve V30a side. The other end of the oil passage L34 is connected to the branch J36a of the oil passage L36. One end of the oil passage L37 is connected to the branch J36b of the oil passage L36, and the other end is connected to the pilot port of the opening pilot valve V30b. One end of the oil passage L38 is connected to the branch J25a of the oil passage L25, and the other end is connected to port 4 of the accumulator-oil supply solenoid valve V35.

[0079] [B-2-2] Control unit 800 The control unit 800 includes a computing unit (not shown) and a memory device (not shown), and is configured to control the operation of the hydraulic circuit unit 100 by the computing unit performing arithmetic processing using a program stored in the memory device. The control unit 800 receives detection signals obtained by detecting the state of each unit. In addition, the control unit 800 receives, for example, an operation command signal input by an operator to an operation device (not shown). Based on the various input signals, the control unit 800 outputs a control signal to the hydraulic circuit unit 100 and controls the operation of the hydraulic servo motor 50, thereby performing the opening and closing operation of the guide vanes 95.

[0080] When performing speed-governing operation of the water turbine 90, the control unit 800 controls the operation of the hydraulic servo motor 50 so as to perform a normal opening operation and a normal closing operation of the guide vane 95. Although details will be described later, when performing a normal opening operation and a normal closing operation, the control unit 800 controls the operation of the closing-side solenoid valve V121a and the opening-side solenoid valve V121b so that the communication between the port a of the bidirectional backing pump 121 and the first hydraulic chamber C52a of the cylinder 52 is blocked, and the communication between the port b of the bidirectional backing pump 121 and the second hydraulic chamber C52b of the cylinder 52 is blocked. The control unit 800 also controls the operation of the accumulator oil supply solenoid valve V35 to establish communication between port a of the bidirectional control pump 110 and the first hydraulic chamber C52a of the cylinder 52, and between port b of the bidirectional control pump 110 and the second hydraulic chamber C52b of the cylinder 52, thereby controlling the operation of the closing pilot valve V30a and the opening pilot valve V30b. When performing a normal closing operation, the control unit 800 controls the supply of hydraulic oil from port a of the bidirectional control pump 110 to the first hydraulic chamber C52a. On the other hand, when performing an opening operation, the control unit 800 controls the supply of hydraulic oil from port b of the bidirectional control pump 110 to the second hydraulic chamber C52b.

[0081] In this embodiment, the control unit 800 executes a pressure accumulation operation to accumulate hydraulic oil in the accumulator 140. Details will be described later, but in this case, the control unit 800 switches the oil collection tank outlet solenoid valve V21 and the accumulator solenoid valve V22 from a closed state to an open state while keeping the closing-side solenoid valve V121a and the opening-side solenoid valve V121b closed. Then, the control unit 800 performs control so that the bidirectional backing pump 121 pumps up hydraulic oil from the oil collection tank 130 via the oil collection tank outlet solenoid valve V21, and the hydraulic oil pumped up by the bidirectional backing pump 121 is supplied to the accumulator 140 via the accumulator solenoid valve V22.

[0082] In this embodiment, when a failure occurs in the bidirectional control pump 110 and operation of the hydraulic turbine 90 is stopped, the control unit 800 controls the operation of the hydraulic servo motor 50 to close the guide vane 95. As will be described in detail later, in this case, the control unit 800 controls the operation of the stored-oil supply solenoid valve V35. As a result, the flow direction of the closing-side pilot valve V30a is switched so that the hydraulic oil stored in the accumulator 140 is supplied to the first hydraulic chamber C52a, and the flow direction of the opening-side pilot valve V30b is switched so that the hydraulic oil is discharged from the second hydraulic chamber C52b to the oil collection tank 130.

[0083] In this embodiment, when a failure occurs in the bidirectional auxiliary pump 121 and operation of the water turbine 90 is stopped, the control unit 800 controls the operation of the hydraulic servo motor 50 to close the guide vanes 95. As will be described in detail later, in this case, the control unit 800 performs control so that hydraulic oil is supplied from the bidirectional control pump 110 to the first hydraulic chamber C52a via the opening-side pilot valve V30b, and so that hydraulic oil is returned from the second hydraulic chamber C52b to the bidirectional control pump 110.

[0084] Additionally, in this embodiment, when a failure occurs in the water turbine 90 and the operation of the water turbine 90 is to be suddenly stopped, the control unit 800 controls the operation of the hydraulic servo motor 50 to perform a sudden closing operation that closes the guide vanes 95 more quickly than a normal closing operation. As will be described in detail later, in this case, the control unit 800 switches the closing-side solenoid valve V121a and the opening-side solenoid valve V121b from the closed state to the open state. Then, the control unit 800 controls the bidirectional control pump 110 and the bidirectional auxiliary pump 121 to supply hydraulic oil to the first hydraulic chamber C52a.

[0085] The hydraulic circuit unit 100 is configured to perform a closing operation on the guide vane 95 when the supply of power to the hydraulic circuit unit 100 and the control unit 800 is cut off due to a power outage (loss of power supply). In other words, the hydraulic circuit unit 100 is configured to stop the operation of the water turbine 90 in the event of a power outage without being controlled by the control unit 800. As will be described in detail later, in this case, the flow direction of the closing pilot valve V30a is switched so that the hydraulic oil stored in the accumulator 140 is supplied to the first hydraulic chamber C52a, and the flow direction of the opening pilot valve V30b is switched so that the hydraulic oil is discharged from the second hydraulic chamber C52b to the oil collection tank 130. As a result, the closing operation of the guide vane 95 is performed.

[0086] [C] Operation The hybrid servo system of this embodiment will be described below with reference to the state where the hydraulic servo motor 50 is driven to open and close the guide vanes 95.

[0087] [C-1] When performing closing operation (Case 1) First, a case (case 1) in which the guide vanes 95 perform a normal closing operation when the water turbine 90 performs a speed-governing operation will be described.

[0088] 3A is a diagram schematically showing a state in which a closing operation is performed for guide vane 95 in the hybrid servo system of the first embodiment. In FIG. 3A, the outline of the flow of hydraulic oil is also indicated by thick solid arrows.

[0089] 3A, when the guide vane 95 is normally closed (case 1), the control unit 800 sets the closing-side solenoid valve V121a to the excited state EG, thereby blocking communication between port 1 and port 2 (closed state). This blocks communication between port a of the bidirectional backing pump 121 and the first hydraulic chamber C52a of the cylinder 52. The control unit 800 also sets the opening-side solenoid valve V121b to the excited state EG, thereby blocking communication between port 1 and port 2 (closed state). This blocks communication between port b of the bidirectional backing pump 121 and the second hydraulic chamber C52b of the cylinder 52.

[0090] The control unit 800 sets the oil collection tank outlet solenoid valve V21 to the demagnetized state DG, thereby blocking communication between port 1 and port 2 (closed state). This results in a state in which communication between port a of the bidirectional backing pump 121 and the oil collection tank 130 is blocked. Furthermore, the control unit 800 sets the pressure-accumulating solenoid valve V22 to the demagnetized state DG, thereby blocking communication between port 1 and port 2 (closed state). This results in a state in which communication between port b of the bidirectional backing pump 121 and the accumulator 140 is blocked.

[0091] Furthermore, the control unit 800 controls the operation of the storage oil supply electromagnetic valve V35, thereby controlling the operation of the closing pilot valve V30a and the opening pilot valve V30b.

[0092] Specifically, the control unit 800 energizes the accumulator oil supply solenoid valve V35 to the excited state EG, thereby establishing communication between ports 1 and 4 and between ports 2 and 3. As a result, in the accumulator oil supply pilot check valve V33, the pressure of hydraulic oil applied to the pilot port is equal to or less than the set value, so no backflow of hydraulic oil occurs from the OUT port to the IN port. In other words, in this hydraulic circuit, pressure oil does not flow to the pilot port, so there is no backflow from the OUT port to the IN port.

[0093] As a result, in the closing pilot valve V30a, the pressure of the hydraulic oil applied to the pilot port falls below the set value, so that communication is established between ports 1 and 2 and between ports 3 and 4. Similarly, in the opening pilot valve V30b, the pressure of the hydraulic oil applied to the pilot port falls below the set value, so that communication is established between ports 1 and 2 and between ports 3 and 4. This establishes communication between port a of the bidirectional control pump 110 and the first hydraulic chamber C52a of the cylinder 52, and between port b of the bidirectional control pump 110 and the second hydraulic chamber C52b of the cylinder 52. In other words, in this hydraulic circuit, pressure oil does not flow to the pilot port, so there is no backflow from the OUT port to the IN port.

[0094] In the above state, the control unit 800 performs control so that the bidirectional control pump 110 sucks up hydraulic oil from port b and discharges it from port a to the oil passage L13, thereby performing a normal closing operation.

[0095] Specifically, the hydraulic oil discharged from the bidirectional control pump 110 to the oil passage L13 flows into the oil passage L11 via the branch point J11b. The section of the oil passage L11 on the side of the bidirectional auxiliary pump 121 relative to the branch point J11b is blocked by the closing solenoid valve V121a. In contrast, the section of the oil passage L11 on the side of the hydraulic servomotor 50 relative to the branch point J11b is open and not blocked by the closing pilot valve V30a. Therefore, the hydraulic oil that flows from the oil passage L13 into the oil passage L11 is supplied to the first hydraulic chamber C52a of the cylinder 52 that constitutes the hydraulic servomotor 50 via the closing pilot valve V30a.

[0096] The pressure in the first hydraulic chamber C52a of the cylinder 52 increases due to the supply of hydraulic oil. As a result, the piston 55 moves from the first hydraulic chamber C52a side to the second hydraulic chamber C52b side in the internal space C52 of the cylinder 52. As a result, the guide vane 95 performs a normal closing operation, and the opening degree of the guide vane 95 decreases in accordance with the pressure difference.

[0097] As the piston 55 moves from the first hydraulic chamber C52a side to the second hydraulic chamber C52b side, hydraulic oil flows out from the second hydraulic chamber C52b to the oil passage L12. The section of the oil passage L12 that is closer to the bidirectional auxiliary pump 121 than the branch point J12b is blocked by the opening solenoid valve V121b. In contrast, the section of the oil passage L12 that is closer to the hydraulic servo motor 50 than the branch point J12b is open and not blocked by the opening pilot valve V30b. Therefore, the hydraulic oil that flows out from the second hydraulic chamber C52b to the oil passage L12 passes through the opening pilot valve V30b, then flows into the oil passage L14 via the branch point J12b and returns to port b of the bidirectional control pump 110.

[0098] [C-2] When performing opening operation (Case 2) Next, a case (case 2) in which the guide vanes 95 perform a normal opening operation when the water turbine 90 performs a speed-governing operation will be described.

[0099] FIG. 3B is a diagram that schematically shows a state in which the guide vane 95 performs an opening operation in the hybrid servo system of the first embodiment.

[0100] As shown in FIG. 3B, the control unit 800 controls each part when the guide vane 95 performs a normal opening operation (case 2) in the same manner as when the guide vane 95 performs a normal closing operation (case 1) (see FIG. 3A).

[0101] In other words, the closing-side solenoid valve V121a, the opening-side solenoid valve V121b, the oil collection tank outlet solenoid valve V21, the accumulator solenoid valve V22, the accumulator oil supply solenoid valve V35, the closing-side pilot valve V30a, and the opening-side pilot valve V30b are in the same states as when the guide vane 95 performs a normal closing operation (Case 1). As a result, communication is blocked between port a of the bidirectional backing pump 121 and the first hydraulic chamber C52a of the cylinder 52, and communication is blocked between port b of the bidirectional backing pump 121 and the second hydraulic chamber C52b of the cylinder 52. Communication is also established between port a of the bidirectional control pump 110 and the first hydraulic chamber C52a of the cylinder 52, and communication is also established between port b of the bidirectional control pump 110 and the second hydraulic chamber C52b of the cylinder 52.

[0102] However, when performing a normal opening operation, unlike when performing a normal closing operation, the control unit 800 controls the bidirectional control pump 110 to suck up hydraulic oil from port a and discharge hydraulic oil from port b to the oil passage L14.

[0103] Specifically, the hydraulic oil discharged from the bidirectional control pump 110 to the oil passage L14 flows into the oil passage L12 via the branch point J12b. The section of the oil passage L12 on the bidirectional auxiliary pump 121 side from the branch point J12b is blocked by the opening solenoid valve V121b. In contrast, the section of the oil passage L12 on the hydraulic servomotor 50 side from the branch point J12b is open and not blocked by the opening pilot valve V30b. Therefore, the hydraulic oil that flows from the oil passage L14 into the oil passage L12 is supplied to the second hydraulic chamber C52b of the cylinder 52 that constitutes the hydraulic servomotor 50 via the opening pilot valve V30b.

[0104] The pressure in the second hydraulic chamber C52b of the cylinder 52 increases due to the supply of hydraulic oil. As a result, the piston 55 moves from the second hydraulic chamber C52b side to the first hydraulic chamber C52a side in the internal space C52 of the cylinder 52. As a result, the guide vane 95 performs a normal opening operation, and the opening degree of the guide vane 95 increases in accordance with the pressure difference.

[0105] As the piston 55 moves from the second hydraulic chamber C52b side to the first hydraulic chamber C52a side, hydraulic oil flows out from the first hydraulic chamber C52a to the oil passage L11. The section of the oil passage L11 that is closer to the bidirectional auxiliary pump 121 than the branch point J11b is blocked by the closing solenoid valve V121a. In contrast, the section of the oil passage L11 that is closer to the hydraulic servo motor 50 than the branch point J11b is open and not blocked by the closing pilot valve V30a. Therefore, the hydraulic oil that has flowed out from the first hydraulic chamber C52a to the oil passage L11 passes through the closing pilot valve V30a, then flows into the oil passage L13 via the branch point J11b and returns to port a of the bidirectional control pump 110.

[0106] [C-3] When pressure accumulation is performed (Case 3) Next, a case where a pressure accumulation operation is performed to accumulate hydraulic oil in the accumulator 140 (Case 3) will be described.

[0107] The pressure accumulation operation is performed when the pressure switch SW22 detects that the pressure of the hydraulic oil in the oil passage L22 connected to the accumulator 140 has fallen below a set value while the bidirectional auxiliary pump 121 is not operating. Then, when the pressure switch SW22 detects that the pressure of the hydraulic oil has risen to or exceeded the set value, the pressure accumulation operation is stopped.

[0108] FIG. 3C is a diagram that schematically shows a state when a pressure accumulation operation for accumulating hydraulic oil in the accumulator 140 is performed in the hybrid servo system of the first embodiment.

[0109] As shown in FIG. 3C, even when pressure accumulation operation is performed (case 3), the closing side solenoid valve V121a, the opening side solenoid valve V121b, the stored oil supply solenoid valve V35, the closing side pilot valve V30a, and the opening side pilot valve V30b are in the same state as when normal closing operation of the guide vane 95 is performed (case 1) (see FIG. 3A).

[0110] However, when pressure accumulation operation is performed (Case 3), the control unit 800 controls the oil collection tank outlet solenoid valve V21 and the pressure accumulation solenoid valve V22 so that they are in a state different from that when normal closing operation is performed (Case 1) (see Figure 3A).

[0111] Specifically, by switching the oil collection tank outlet solenoid valve V21 from the demagnetized state DG to the energized state EG, the oil collection tank outlet solenoid valve V21 switches to a state in which port 1 and port 2 are communicated with each other. At the same time, by switching the pressure accumulating solenoid valve V22 from the demagnetized state DG to the energized state EG, the pressure accumulating solenoid valve V22 switches to a state in which port 1 and port 2 are communicated with each other. That is, the control unit 800 switches the oil collection tank outlet solenoid valve V21 and the pressure accumulating solenoid valve V22 from a closed state to an open state, with the closing-side solenoid valve V121a and the opening-side solenoid valve V121b kept closed.

[0112] Furthermore, as shown in FIG. 3C, the control unit 800 performs control so that the hydraulic oil is sucked up into the port a of the bidirectional auxiliary pump 121 and discharged from the port b of the bidirectional auxiliary pump 121.

[0113] 3C, the hydraulic oil stored in the oil collection tank 130 is pumped up to port a of the bidirectional auxiliary pump 121. At this time, the oil collection tank outlet solenoid valve V21 is in a communicating state and the oil passage L21 is in an open state, so the hydraulic oil stored in the oil collection tank 130 passes through the oil passage L21 and flows into the oil passage L11 via the branch point J11a. The portion of the oil passage L11 closer to the hydraulic servomotor 50 than the branch point J11a is closed by the closing-side solenoid valve V121a. For this reason, the hydraulic oil that has flowed into the branch point J11a of the oil passage L11 flows toward the bidirectional auxiliary pump 121 without flowing toward the hydraulic servomotor 50, and is pumped up into port a of the bidirectional auxiliary pump 121. The hydraulic oil is then discharged from port b of the bidirectional auxiliary pump 121.

[0114] As shown in Fig. 3C, the hydraulic oil discharged from the bidirectional auxiliary pump 121 flows into the branch point J12a of the oil passage L12. The portion of the oil passage L12 closer to the hydraulic servomotor 50 than the branch point J12a is closed by the opening-side solenoid valve V121b. Therefore, the hydraulic oil that has flowed into the branch point J12a of the oil passage L12 does not flow toward the hydraulic servomotor 50, but instead flows into the oil passage L22 in which the pressure-accumulating solenoid valve V22 is installed. Because the pressure-accumulating solenoid valve V22 is in a communicating state, the hydraulic oil flows into the branch point J22a of the oil passage L22.

[0115] The oil passage L22 is blocked from the branch point J22a toward the other end J22b. Similarly, one end of the oil passage L32, which is connected to the branch point J22a of the oil passage L22, is connected to the closed oil passage L35 via the stored-oil supply solenoid valve V35 at the other end. Therefore, the hydraulic oil flowing into the branch point J22a is supplied to the accumulator 140 via the oil passage L31.

[0116] In this way, in the pressure accumulation operation, the two-way auxiliary pump 121 pumps up hydraulic oil from the oil collection tank 130 via the oil collection tank outlet solenoid valve V21, and the hydraulic oil pumped up by the two-way auxiliary pump 121 is supplied to the accumulator 140 via the pressure accumulation solenoid valve V22.

[0117] As described above, the pressure accumulation operation is performed when the closing-side solenoid valve V121a and the opening-side solenoid valve V121b are closed and the communication between the bidirectional control pump 110 and the bidirectional auxiliary pump 121 is cut off. That is, the pressure accumulation operation is performed in the hydraulic circuit unit 100 while the part (hydraulic servo motor operation circuit unit) that performs the normal closing operation and normal opening operation is disconnected from the part (accumulation circuit unit) that performs the pressure accumulation operation. Therefore, in this embodiment, even when the bidirectional control pump 110 is performing the normal closing operation and normal opening operation of the guide vane 95, the bidirectional auxiliary pump 121 can be used to perform the pressure accumulation operation of supplying hydraulic oil to the accumulator 140. Therefore, in this embodiment, hydraulic control is possible while maintaining the speed regulation function, and the pressure accumulation operation can be performed even when the hydraulic turbine is operating. This makes it easy to maintain a constant hydraulic pressure in the accumulator 140. As a result, the hybrid servo system of this embodiment can accurately control the opening of the guide vanes of the hydraulic turbine.

[0118] [C-4] When a failure occurs in the bidirectional control pump 110 (Case 4) Next, a case where a failure occurs in the bidirectional control pump 110 and the guide vane 95 performs a closing operation (Case 4) will be described.

[0119] The control unit 800 determines whether the bidirectional control pump 110 has a malfunction, based on the result of detection by the displacement detection unit 500 of the displacement amount of the guide vane 95 when the bidirectional control pump 110 is driven. For example, the control unit 800 determines whether the bidirectional control pump 110 has a malfunction when the guide vane 95 performs a normal closing operation and a normal opening operation. Here, the control unit 800 stores, for example, the relationship between the operation of the normal bidirectional control pump 110 and the displacement amount of the guide vane 95, and determines that a malfunction has occurred in the bidirectional control pump 110 when the displacement amount of the guide vane 95 differs by a predetermined value or more from the value for a normal bidirectional control pump 110 for a set period of time or longer. When the control unit 800 determines that a malfunction has occurred in the bidirectional control pump 110, it performs a closing operation of the guide vane 95, bringing the guide vane 95 into a fully closed state.

[0120] FIG. 3D is a diagram schematically showing a state in which a failure occurs in the bidirectional control pump 110 and the guide vane 95 performs a closing operation in the hybrid servo system of the first embodiment.

[0121] As shown in FIG. 3D, even when a failure occurs in the bidirectional control pump 110 and the guide vane 95 is closed (case 4), the closing side solenoid valve V121a, the opening side solenoid valve V121b, the oil collection tank outlet solenoid valve V21, and the pressure storage solenoid valve V22 are in the same state as when the guide vane 95 is normally closed (case 1) (see FIG. 3A).

[0122] However, in this case, the control unit 800 controls the stored oil supply electromagnetic valve V35 to a state different from that in the case where the normal closing operation is performed (Case 1).

[0123] Specifically, by switching the accumulator oil supply solenoid valve V35 from the energized state EG to the de-energized state DG, the accumulator oil supply solenoid valve V35 establishes communication between ports 1 and 2 and between ports 3 and 4. As a result, the hydraulic oil stored in the accumulator 140 acts on the pilot port of the accumulator oil supply pilot check valve V33, the pilot port of the closing-side pilot valve V30a, and the pilot port of the opening-side pilot valve V30b via oil passages L31, L32, L32, the accumulator oil supply solenoid valve V35, oil passages L34, L36, and L37.

[0124] As a result, in the accumulator oil supply pilot check valve V33, the pressure of hydraulic oil applied to the pilot port exceeds the set value, allowing backflow of hydraulic oil from the OUT port to the IN port. In the closing pilot valve V30a, the pressure of hydraulic oil applied to the pilot port exceeds the set value, so communication is established between ports 1 and 4 and between ports 2 and 3. Similarly, in the opening pilot valve V30b, the pressure of hydraulic oil applied to the pilot port exceeds the set value, so communication is established between ports 1 and 4 and between ports 2 and 3.

[0125] Accordingly, the hydraulic oil stored in the accumulator 140 passes through the stored oil supply pilot check valve V33 and the closing pilot valve V30a in this order, and is supplied to the first hydraulic chamber C52a of the cylinder 52 that constitutes the hydraulic servomotor 50.

[0126] The pressure in the first hydraulic chamber C52a of the cylinder 52 increases due to the supply of hydraulic oil. As a result, the piston 55 moves from the first hydraulic chamber C52a side to the second hydraulic chamber C52b side in the internal space C52 of the cylinder 52. As a result, the guide vane 95 performs a closing operation.

[0127] As the piston 55 moves from the first hydraulic chamber C52a to the second hydraulic chamber C52b, hydraulic oil flows out of the second hydraulic chamber C52b into the oil passage L12. The hydraulic oil that flows out of the second hydraulic chamber C52b into the oil passage L12 flows into the oil passage L24 via the opening pilot valve V30b. The hydraulic oil that flows into the oil passage L24 is discharged into the oil collection tank 130 and stored there.

[0128] In this manner, in this embodiment, when a failure occurs in the bidirectional control pump 110, the emergency operation circuit section including the accumulator 140 in the hydraulic circuit section 100 performs the closing operation on the guide vanes 95.

[0129] When determining whether a failure of the bidirectional control pump 110 is occurring based on the rotation speed or current value of the electric motor that drives the bidirectional control pump 110, it is not possible to determine the failure with high accuracy under operating conditions where the rotation speed or current value is extremely low. However, as described above, in this embodiment, a failure of the bidirectional control pump 110 is determined based on the displacement amount of the guide vane 95, rather than on the rotation speed or current value of the electric motor that drives the bidirectional control pump 110. Therefore, in this embodiment, a failure of the bidirectional control pump 110 can be determined with high accuracy.

[0130] Furthermore, in this embodiment, it is possible to distinguish and grasp a failure of the bidirectional control pump 110 from a failure of the bidirectional auxiliary pump 121, so that when a failure occurs in the bidirectional control pump 110, the closing operation of the guide vane 95 can be performed appropriately.

[0131] [C-5] When the bidirectional auxiliary pump 121 fails (Case 5) Next, a case where a failure occurs in the bidirectional auxiliary pump 121 and the guide vane 95 performs a closing operation (Case 5) will be described.

[0132] The determination of whether the bidirectional backing pump 121 has a malfunction is made by the control unit 800, for example, based on the drive conditions (rotation speed, current value, etc.) of the bidirectional backing pump 121 and the result detected by the pressure switch SW22 regarding the amount of pressure change (pressure increase) by which the pressure of the hydraulic oil changes when the bidirectional backing pump 121 is driven under those drive conditions. The determination of whether the bidirectional backing pump 121 has a malfunction is made, for example, when the pressure accumulation operation is performed. Here, the control unit 800 stores, for example, the relationship between the normal operation of the bidirectional backing pump 121 and the amount of pressure change by which the pressure of the hydraulic oil changes, and switches the pressure switch SW22 when the amount of pressure change by which the pressure of the hydraulic oil changes when the bidirectional backing pump 121 is driven differs by a predetermined value or more from the value for a normal bidirectional backing pump 121, and if this state continues beyond a set time, it is determined that a malfunction has occurred in the bidirectional backing pump 121. When the control unit 800 determines that a failure has occurred in the bidirectional auxiliary pump 121, it performs a closing operation on the guide vanes 95, bringing the guide vanes 95 into a fully closed state.

[0133] FIG. 3E is a diagram schematically showing a state in which a failure occurs in the bidirectional auxiliary pump 121 and the guide vane 95 performs a closing operation in the hybrid servo system of the first embodiment.

[0134] 3E, when a failure occurs in the bidirectional auxiliary pump 121 and the guide vane 95 is to be closed (Case 5), the control unit 800 controls each part in the same way as when the guide vane 95 is to be normally closed (Case 1) (see FIG. 3A). In other words, the control unit 800 controls each part so that the hydraulic oil is supplied from the bidirectional control pump 110 to the first hydraulic chamber C52a via the opening-side pilot valve V30b, and so that the hydraulic oil is returned from the second hydraulic chamber C52b to the bidirectional control pump 110.

[0135] When determining whether a failure has occurred in the bidirectional auxiliary pump 121 based on the rotation speed or current value of the electric motor that drives the bidirectional auxiliary pump 121, it is not possible to determine the failure with high accuracy under operating conditions where the rotation speed or current value is extremely low. However, as described above, in this embodiment, a failure of the bidirectional auxiliary pump 121 is determined based on the amount of pressure change in the pressure of the hydraulic oil, rather than based on the rotation speed or current value of the electric motor that drives the bidirectional auxiliary pump 121. Therefore, in this embodiment, a failure of the bidirectional auxiliary pump 121 can be determined with high accuracy.

[0136] Furthermore, in this embodiment, it is possible to distinguish and grasp a failure of the bidirectional auxiliary pump 121 from a failure of the bidirectional control pump 110, so that when a failure occurs in the bidirectional auxiliary pump 121, the closing operation of the guide vane 95 can be performed appropriately.

[0137] [C-6] When performing sudden closing operation (Case 6) Next, a case (Case 6) will be described in which a malfunction occurs in the water turbine 90 and a sudden closing operation is performed to close the guide vanes 95 more quickly than in a normal closing operation.

[0138] The presence or absence of a malfunction in the water turbine 90 is determined, for example, based on the detection results of a sensor installed in the water turbine 90. When it is determined that a malfunction has occurred in the water turbine 90, the control unit 800 performs a quick closing operation on the guide vanes 95, bringing the guide vanes 95 into a fully closed state.

[0139] FIG. 3F is a diagram that schematically shows a state in which the guide vane 95 performs a sudden closing operation in the hybrid servo system of the first embodiment.

[0140] As shown in Figure 3F, even when a sudden closing operation is performed (Case 6), the oil collection tank outlet solenoid valve V21, the pressure storage solenoid valve V22, the pressure storage oil supply solenoid valve V35, the closing pilot valve V30a, and the opening pilot valve V30b are each in the same state as when a normal closing operation is performed for the guide vane 95 (Case 1) (see Figure 3A).

[0141] However, when a sudden closing operation is performed (Case 6), the control unit 800 controls the closing-side solenoid valve V121a and the opening-side solenoid valve V121b to a state different from that when a normal closing operation is performed (Case 1) (see FIG. 3A). Specifically, by switching the closing-side solenoid valve V121a from the excited state EG to the demagnetized state DG, the closing-side solenoid valve V121a switches to a state where port 1 and port 2 are communicated. At the same time, by switching the opening-side solenoid valve V121b from the excited state EG to the demagnetized state DG, the opening-side solenoid valve V121b switches to a state where port 1 and port 2 are communicated.

[0142] In the above state, the control unit 800 controls the bidirectional control pump 110 and the bidirectional auxiliary pump 121 so that both pump up hydraulic oil from port b and discharge hydraulic oil from port a to the oil passage L13. For this reason, in this embodiment, hydraulic oil is supplied from the bidirectional control pump 110 to the first hydraulic chamber C52a via the close-side pilot valve V30a, and hydraulic oil is supplied from the bidirectional auxiliary pump 121 to the first hydraulic chamber C52a sequentially via the close-side solenoid valve V121a and the close-side pilot valve V30a. As a result, a quick-closing operation is performed on the guide vane 95.

[0143] The sudden closing operation may be performed for reasons other than a failure of the water turbine 90. For example, the sudden closing operation may be performed when a failure occurs in any of the devices in the hydraulic circuit section 100 of the hybrid servo system, excluding the bidirectional control pump 110, the bidirectional auxiliary pump 121, the closing-side solenoid valve V121a, the opening-side solenoid valve V121b, the oil collection tank outlet solenoid valve V21, and the pressure-accumulating solenoid valve V22.

[0144] [C-7] When a power outage occurs (Case 7) Next, a case (Case 7) will be described in which the supply of power to the hydraulic circuit section 100 and the control section 800 is cut off due to a power outage and the closing operation for closing the guide vanes 95 is performed.

[0145] FIG. 3G is a diagram that schematically shows a state in which the hybrid servo system of the first embodiment performs a closing operation to close the guide vanes 95 in the event of a power outage.

[0146] In this embodiment, when a power outage occurs, as shown in FIG. 3G, the closing operation of the guide vane 95 is performed using the emergency operation circuit unit including the accumulator 140 in the hydraulic circuit unit 100, similar to the case where a failure occurs in the bidirectional control pump 110 and the closing operation of the guide vane 95 is performed (Case 4) (see FIG. 3D).

[0147] Specifically, when a power outage occurs, the closing solenoid valve V121a, the opening solenoid valve V121b, the oil collection tank outlet solenoid valve V21, and the pressure accumulation solenoid valve V22 enter the demagnetized state DG.

[0148] The accumulator oil supply solenoid valve V35 also enters the demagnetized state DG. As a result, the accumulator oil supply solenoid valve V35 enters a state of communication between ports 1 and 2 and between ports 3 and 4. The closing pilot valve V30a and the opening pilot valve V30b enter a state of communication between ports 1 and 4 and between ports 2 and 3. In other words, the flow direction of the closing pilot valve V30a switches so that the hydraulic oil accumulated in the accumulator 140 is supplied to the first hydraulic chamber C52a, and the flow direction of the opening pilot valve V30b switches so that the hydraulic oil is discharged from the second hydraulic chamber C52b to the oil collection tank 130.

[0149] Therefore, when a power outage cuts off the supply of power to the hydraulic circuit section 100 and the control section 800, the closing operation of the guide vane 95 is performed without the control of the control section 800, and the guide vane 95 is brought into a fully closed state.

[0150] In addition, when the supply of power to the bidirectional control pump 110 and the bidirectional auxiliary pump 121 in the hydraulic circuit section 100 is cut off but the supply of power to the control section 800 is not cut off, the control section 800 may execute the above operation by switching each solenoid valve to a demagnetized state.

[0151] [C-8] Other In the hydraulic circuit section 100 of this embodiment, the closing pilot check valve V15a, the opening pilot check valve V15b, the closing relief valve V16a, the opening relief valve V16b, the closing check valve V18a, and the opening check valve V18b are each provided to keep the pressure of the hydraulic oil in the hydraulic circuit section 100 within a predetermined range. Specifically, the closing relief valve V16a and the opening relief valve V16b function as protection valves in the event of an abnormal rise in pressure. Furthermore, the closing pilot check valve V15a and the opening pilot check valve V15b function as valves for independently controlling the opening and closing hydraulic pressures.

[0152] Second Embodiment [A] Configuration of hydraulic circuit section 100 FIG. 4 is a diagram schematically showing the hydraulic servo motor 50 and hybrid servo system for performing opening and closing operations on the guide vanes 95 of the water turbine 90 (see FIG. 1) in the second embodiment.

[0153] As shown in Fig. 4, in this embodiment, the configuration of the hydraulic servo motor 50 is the same as that in the first embodiment (see Fig. 2). However, in this embodiment, the configuration of part of the hydraulic circuit section 100 of the hybrid servo system is different from that in the first embodiment (see Fig. 2).

[0154] Specifically, in this embodiment, two bidirectional auxiliary pumps, 121A (first bidirectional auxiliary pump) and 121B (second bidirectional auxiliary pump), are included as the bidirectional auxiliary pump 121 (see FIG. 2) of the first embodiment.

[0155] In this embodiment, the closing-side solenoid valve V121a (see FIG. 2) of the first embodiment includes two: a closing-side solenoid valve V121Aa (first closing-side solenoid valve) and a closing-side solenoid valve V121Ba (second closing-side solenoid valve). In this embodiment, the opening-side solenoid valve V121b (see FIG. 2) of the first embodiment includes two: an opening-side solenoid valve V121Ab (first opening-side solenoid valve) and an opening-side solenoid valve V121Bb (second opening-side solenoid valve).

[0156] In this embodiment, the oil collection tank outlet solenoid valve V21 (see FIG. 2) of the first embodiment includes two: an oil collection tank outlet solenoid valve V21A (first oil collection tank outlet solenoid valve) and an oil collection tank outlet solenoid valve V21B (second oil collection tank outlet solenoid valve). In this embodiment, the oil passage L21 (see FIG. 2) of the first embodiment includes two: an oil passage L21A and an oil passage L21B. In this embodiment, the gate valve SV21 (see FIG. 2) of the first embodiment includes two: a gate valve SV21A and a gate valve SV21B.

[0157] Except for the above points, this embodiment is the same as the first embodiment (see FIG. 2), so explanations of overlapping matters will be omitted where appropriate.

[0158] [A-1] Bidirectional auxiliary pump 121A, bidirectional auxiliary pump 121B The bidirectional auxiliary pump 121A and the bidirectional auxiliary pump 121B are installed in parallel with the bidirectional control pump 110.

[0159] The bidirectional auxiliary pump 121A is installed to supply hydraulic oil upstream of the bidirectional control pump 110. That is, port a of the bidirectional auxiliary pump 121A is configured to supply hydraulic oil to the first hydraulic chamber C52a upstream of port a of the bidirectional control pump 110. Furthermore, port b of the bidirectional auxiliary pump 121A is configured to supply hydraulic oil to the second hydraulic chamber C52b upstream of port b of the bidirectional control pump 110.

[0160] The bidirectional backing pump 121B is installed to supply hydraulic oil upstream of the bidirectional backing pump 121A. That is, port a of the bidirectional backing pump 121B is configured to supply hydraulic oil to the first hydraulic chamber C52a upstream of port a of the bidirectional backing pump 121A. Furthermore, port b of the bidirectional backing pump 121B is configured to supply hydraulic oil to the second hydraulic chamber C52b upstream of port b of the bidirectional backing pump 121A.

[0161] Here, one end of the oil passage L11 is connected to a port a of the bidirectional auxiliary pump 121B, and one end of the oil passage L12 is connected to a port b of the bidirectional auxiliary pump 121B.

[0162] In a portion of the oil passage L11 that is closer to the bidirectional auxiliary pump 121B than the branch point J11a, a branch point J11g and a branch point J11h are provided in this order from the bidirectional auxiliary pump 121B side toward the cylinder 52 side. One end of the oil passage L41 is connected to the branch point J11h of the oil passage L11, and the other end of the oil passage L41 is connected to port a of the bidirectional auxiliary pump 121A.

[0163] In a portion of the oil passage L12 that is closer to the bidirectional auxiliary pump 121B than the branch point J12a, a branch point J12g and a branch point J12h are provided in this order from the bidirectional auxiliary pump 121B side toward the cylinder 52 side. One end of the oil passage L42 is connected to the branch point J12h of the oil passage L12, and the other end of the oil passage L42 is connected to the port b of the bidirectional auxiliary pump 121A.

[0164] [A-2] Closing solenoid valve V121Aa, closing solenoid valve V121Ba The closing solenoid valve V121Aa is provided in the oil passage L11 between the branch points J11a and J11b, and the closing solenoid valve V121Ba is provided in the oil passage L11 between the branch points J11g and J11h.

[0165] [A-3] Open side solenoid valve V121Ab, open side solenoid valve V121Bb The opening solenoid valve V121Ab is provided in the oil passage L12 between the branching points J12a and J12b, and the opening solenoid valve V121Bb is provided in the oil passage L12 between the branching points J12g and J12h.

[0166] [A-4] Oil collection tank outlet solenoid valve V21A, oil collection tank outlet solenoid valve V21B The oil collection tank outlet solenoid valve V21A is provided in the oil passage L21A. One end of the oil passage L21A is connected to a branch point J11a of the oil passage L11, and the other end is connected to the oil collection tank 130. A gate valve SV21A is provided in the oil passage L21A at a portion located closer to the oil collection tank 130 than the oil collection tank outlet solenoid valve V21A.

[0167] The oil collection tank outlet solenoid valve V21B is provided in the oil passage L21B. One end of the oil passage L21B is connected to a branch point J11g of the oil passage L11, and the other end is connected to the oil collection tank 130. A gate valve SV21B is provided in the oil passage L21B at a portion located closer to the oil collection tank 130 than the oil collection tank outlet solenoid valve V21B.

[0168] [B] Operation The hybrid servo system of this embodiment will be described below with reference to the state where the hydraulic servo motor 50 is driven to open and close the guide vanes 95.

[0169] [B-1] When performing closing operation (Case 1) First, a case where the guide vane 95 performs a normal closing operation (Case 1) will be described.

[0170] FIG. 5A is a diagram schematically showing a state in which the guide vane 95 performs a closing operation in the hybrid servo system of the second embodiment.

[0171] 5A, when the guide vane 95 is normally closed (case 1), the control unit 800 sets the closing-side solenoid valve V121Aa and the closing-side solenoid valve V121Ba to the excited state EG to block communication between port 1 and port 2, and sets the opening-side solenoid valve V121Ab and the opening-side solenoid valve V121Bb to the excited state EG to block communication between port 1 and port 2. As a result, communication between ports a of the bidirectional backing pump 121A and the bidirectional backing pump 121B and the first hydraulic chamber C52a of the cylinder 52 is blocked, and communication between ports b of the bidirectional backing pump 121A and the bidirectional backing pump 121B and the second hydraulic chamber C52b of the cylinder 52 is blocked.

[0172] In addition, the control unit 800 puts the oil collection tank outlet solenoid valve V21A and the oil collection tank outlet solenoid valve V21B into a demagnetized state DG to block communication between port 1 and port 2, and puts the pressure storage solenoid valve V22 into a demagnetized state DG to block communication between port 1 and port 2.

[0173] Furthermore, the control unit 800 sets the accumulator oil supply solenoid valve V35 to the excited state EG, thereby establishing communication between port 1 and port 4 and between port 2 and port 3. This prevents backflow of hydraulic oil from the OUT port to the IN port in the accumulator oil supply pilot check valve V33. As a result, communication is established between port 1 and port 2 and between port 3 and port 4 in the closing pilot valve V30a and the opening pilot valve V30b. Accordingly, communication is established between port a of the bidirectional control pump 110 and the first hydraulic chamber C52a of the cylinder 52, and communication is established between port b of the bidirectional control pump 110 and the second hydraulic chamber C52b of the cylinder 52.

[0174] In the above state, as in the case of the first embodiment (see FIG. 3A), the control unit 800 controls the bidirectional control pump 110 to suck up hydraulic oil from port b and discharge it from port a into the oil passage L13, thereby performing the normal closing operation of the guide vane 95.

[0175] [B-2] When performing opening operation (Case 2) Next, a case where the guide vane 95 performs a normal opening operation (case 2) will be described.

[0176] FIG. 5B is a diagram schematically showing a state in which the guide vane 95 performs an opening operation in the hybrid servo system of the second embodiment.

[0177] As shown in FIG. 5B, even when the guide vane 95 is subjected to a normal opening operation (case 2), the closing solenoid valve V121Aa, the closing solenoid valve V121Ba, the opening solenoid valve V121Ab, the opening solenoid valve V121Bb, the oil collection tank outlet solenoid valve V21A, the oil collection tank outlet solenoid valve V21B, the storage solenoid valve V22, the storage oil supply solenoid valve V35, the closing pilot valve V30a, and the opening pilot valve V30b are in the same state as when the guide vane 95 is subjected to a normal closing operation (case 1).

[0178] However, when performing a normal opening operation, unlike when performing a normal closing operation, the control unit 800 controls the bidirectional control pump 110 to suck up hydraulic oil from port a and discharge hydraulic oil from port b to the oil passage L14.

[0179] [B-3] When pressure accumulation operation is performed using the bidirectional auxiliary pump 121A (Case 3-1) Next, a case (Case 3-1) in which the bidirectional auxiliary pump 121A is used to perform a pressure accumulation operation in which hydraulic oil is accumulated in the accumulator 140 will be described.

[0180] FIG. 5C is a diagram schematically showing a state in which a pressure accumulation operation is performed to accumulate hydraulic oil in the accumulator 140 using the bidirectional auxiliary pump 121A in the hybrid servo system of the second embodiment.

[0181] 5C, when the pressure accumulating operation is performed using the bidirectional backing pump 121A (case 3-1), the control unit 800 switches the oil collection tank outlet solenoid valve V21A and the accumulating solenoid valve V22 from a closed state to an open state (=excited state EG) with the closing-side solenoid valve V121Aa, the closing-side solenoid valve V121Ba, the opening-side solenoid valve V121Ab, and the opening-side solenoid valve V121Bb closed (=excited state EG). Then, the bidirectional backing pump 121A pumps up hydraulic oil from the oil collection tank 130 via the oil collection tank outlet solenoid valve V21A, and the hydraulic oil pumped up by the bidirectional backing pump 121A is supplied to the accumulator 140 via the accumulating solenoid valve V22.

[0182] [B-4] When pressure accumulation operation is performed using the bidirectional auxiliary pump 121B (Case 3-2) Next, a case (Case 3-2) in which the pressure accumulation operation of accumulating hydraulic oil in the accumulator 140 is performed using the bidirectional auxiliary pump 121B will be described.

[0183] FIG. 5D is a diagram schematically showing a state in which a pressure accumulation operation is performed to accumulate hydraulic oil in the accumulator 140 using the bidirectional auxiliary pump 121B in the hybrid servo system of the second embodiment.

[0184] 5D, when the pressure accumulating operation is performed using the bidirectional backing pump 121B (case 3-2), the control unit 800 switches the oil collection tank outlet solenoid valve V21B and the accumulating solenoid valve V22 from a closed state to an open state (=excited state EG) while keeping the closing-side solenoid valve V121Aa, the closing-side solenoid valve V121Ba, the opening-side solenoid valve V121Ab, and the opening-side solenoid valve V121Bb closed (=excited state EG). Then, the bidirectional backing pump 121B pumps up hydraulic oil from the oil collection tank 130 via the oil collection tank outlet solenoid valve V21B, and the hydraulic oil pumped up by the bidirectional backing pump 121B is supplied to the accumulator 140 via the accumulating solenoid valve V22.

[0185] The pressure accumulation operation is performed by alternately using the bidirectional auxiliary pump 121A and the bidirectional auxiliary pump 121B, for example.

[0186] [B-5] When a failure occurs in the bidirectional control pump 110 (Case 4) Next, a case where a failure occurs in the bidirectional control pump 110 and the guide vane 95 performs a closing operation (Case 4) will be described.

[0187] FIG. 5E is a diagram schematically showing a state in which a failure occurs in the bidirectional control pump 110 and the guide vane 95 performs a closing operation in the hybrid servo system of the second embodiment.

[0188] 5E, when a failure occurs in the bidirectional control pump 110 and the guide vane 95 is to be closed (Case 4), the control unit 800 changes the stored-oil supply solenoid valve V35 from the energized state EG to the de-energized state DG, as in the first embodiment (see FIG. 3D). As a result, the flow direction of the closing-side pilot valve V30a is switched so that the hydraulic oil stored in the accumulator 140 is supplied to the first hydraulic chamber C52a, and the flow direction of the opening-side pilot valve V30b is switched so that the hydraulic oil is discharged from the second hydraulic chamber C52b to the oil collection tank 130.

[0189] [B-6] When the bidirectional backing pump 121A and the bidirectional backing pump 121B fail (Case 5) Next, a case (Case 5) in which a failure occurs in the bidirectional auxiliary pump 121A and the bidirectional auxiliary pump 121B and the guide vane 95 performs a closing operation will be described.

[0190] FIG. 5F is a diagram schematically showing a state in which a failure occurs in the bidirectional auxiliary pump 121A and the bidirectional auxiliary pump 121B in the hybrid servo system of the second embodiment, causing the guide vane 95 to perform a closing operation.

[0191] 5F, when a failure occurs in the bidirectional auxiliary pump 121A and the bidirectional auxiliary pump 121B and the guide vane 95 is to be closed (Case 5), the control unit 800 controls each part in the same way as when the normal closing operation is to be performed on the guide vane 95 (Case 1). In other words, the control unit 800 controls each part so that the hydraulic oil is supplied from the bidirectional control pump 110 to the first hydraulic chamber C52a via the opening-side pilot valve V30b, and so that the hydraulic oil is returned from the second hydraulic chamber C52b to the bidirectional control pump 110.

[0192] Although the above operation is performed when a failure occurs in the bidirectional backing pump 121A and the bidirectional backing pump 121B, the present invention is not limited to this. The above operation may be performed when a failure occurs in either the bidirectional backing pump 121A or the bidirectional backing pump 121B.

[0193] [B-7] When performing sudden closing operation (Case 6) Next, a case (Case 6) will be described in which a malfunction occurs in the water turbine 90 and a sudden closing operation is performed to close the guide vanes 95 more quickly than in a normal closing operation.

[0194] FIG. 5G is a diagram that schematically shows a state in which the guide vane 95 performs a sudden closing operation in the hybrid servo system of the second embodiment.

[0195] 5G, when a quick-closing operation is performed (Case 6), the control unit 800 switches the closing-side solenoid valve V121Aa, the closing-side solenoid valve V121Ba, the opening-side solenoid valve V121Ab, and the opening-side solenoid valve V121Bb from the closed state to the open state (=demagnetized state DG). Then, the control unit 800 supplies hydraulic oil to the first hydraulic chamber C52a from each of the bidirectional control pump 110, the bidirectional auxiliary pump 121A, and the bidirectional auxiliary pump 121B.

[0196] [B-8] When a power outage occurs (Case 7) Next, a case (Case 7) will be described in which the supply of power to the hydraulic circuit section 100 and the control section 800 is cut off due to a power outage and the closing operation for closing the guide vanes 95 is performed.

[0197] FIG. 5H is a diagram that schematically shows a state in which the hybrid servo system of the second embodiment performs a closing operation to close the guide vanes 95 in the event of a power outage.

[0198] When a power outage occurs, as shown in FIG. 5H, the closing solenoid valve V121Aa, the closing solenoid valve V121Ba, the opening solenoid valve V121Ab, the opening solenoid valve V121Bb, the oil collection tank outlet solenoid valve V21A, the oil collection tank outlet solenoid valve V21B, and the pressure storage solenoid valve V22 enter the demagnetized state DG.

[0199] Similarly, the stored oil supply solenoid valve V35 also enters the demagnetized state DG. Accordingly, the flow direction of the closing pilot valve V30a switches so that the hydraulic oil stored in the accumulator 140 is supplied to the first hydraulic chamber C52a. Also, the flow direction of the opening pilot valve V30b switches so that the hydraulic oil is discharged from the second hydraulic chamber C52b to the oil collection tank 130.

[0200] Therefore, when a power outage cuts off the supply of power to the hydraulic circuit section 100 and the control section 800, the closing operation of the guide vane 95 is performed without the control of the control section 800, and the guide vane 95 is brought into a fully closed state.

[0201] [C] Variation In the above embodiment, the case where there are two bidirectional backing pumps 121 (bidirectional backing pump 121A and bidirectional backing pump 121B) has been described, but this is not limiting. Naturally, there may be three or more bidirectional backing pumps 121. In that case, three or more closing-side solenoid valves V121a, opening-side solenoid valves V121b, and oil collection tank outlet solenoid valves V21 are also similarly provided corresponding to the three or more bidirectional backing pumps 121.

[0202] <Other> Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0203] 50: Hydraulic servo motor, 51: Operating rod, 52: Cylinder, 55: Piston, 90: Water wheel, 91: Runner, 92: Main shaft, 93: Upper cover, 94: Lower cover, 95: Guide vane, 96: Casing, 97: Discharge pipe, 98: Generator, 100: Hydraulic circuit section, 110: Bidirectional control pump, 121: Bidirectional auxiliary pump, 121A: Bidirectional auxiliary pump (first bidirectional auxiliary pump), 121B: Bidirectional auxiliary pump (second bidirectional auxiliary pump), 130: Oil collection tank, 140: Accumulator, 500: Displacement detection section, 800: Control section, 911: Runner crown, 912: Runner band, 913: Runner blade, C52: Internal space, C52a: First hydraulic chamber, C52b: Second hydraulic chamber, DG: Demagnetized state, EG: Energized State, J11a to J11h, J12a to J12h, J15 to J18, J22a, J25a, J25b, J32, J36a, J36b: Branching section, J22b: Other end, L11 to L18, L11c, L12c, L17a, L21 to L26, L31 to L38, L41, L42: Oil passage, P52a: First hydraulic oil port, P52b: Second hydraulic oil port, SV17: Gate valve, SV21: Gate valve, SV21A: Gate valve, SV21B: Gate valve, SV22a: Gate valve, SV22b: Closed gate valve, SV32: Gate valve, SW22: Pressure switch, SW34: Pressure switch, SW35 Pressure switch, V121a: closing solenoid valve, V121Aa: closing solenoid valve (first closing solenoid valve), V121Ab: opening solenoid valve (first opening solenoid valve), V121b: opening solenoid valve, V121Ba: closing solenoid valve (second closing solenoid valve), V121Bb: opening solenoid valve (second opening solenoid valve), V15a: closing pilot check valve, V15b: opening pilot check valve, V16a: closing relief valve, V16b: Opening side relief valve, V18a: Closing side check valve, V18b: Opening side check valve, V21: Oil collection tank outlet solenoid valve, V21A: Oil collection tank outlet solenoid valve (first oil collection tank outlet solenoid valve), V21B: Oil collection tank outlet solenoid valve (second oil collection tank outlet solenoid valve V21B), V22: Accumulator solenoid valve, V30a: Closing side pilot valve, V30b: Opening side pilot valve, V33: Accumulator oil supply pilot check valve, V35: Accumulator oil supply solenoid valve

Claims

1. a hydraulic circuit unit that drives a hydraulic servo motor for performing opening and closing operations on the guide vanes of the water turbine; a control unit for controlling the operation of the hydraulic circuit unit; A hybrid servo system comprising: The hydraulic servo motor a piston provided on an operating rod that operates the guide vane; a cylinder that accommodates the piston in an internal space, the internal space being divided into a first hydraulic chamber and a second hydraulic chamber by the piston; and The hydraulic circuit section includes: a bidirectional control pump configured to supply hydraulic oil to the first hydraulic chamber via a closing-side pilot valve when performing the closing operation, and to supply hydraulic oil to the second hydraulic chamber via an opening-side pilot valve when performing the opening operation; a bidirectional auxiliary pump that is installed in parallel with the bidirectional control pump and is configured to supply hydraulic oil to the first hydraulic chamber via a closing-side solenoid valve and the closing-side pilot valve in that order, and to supply hydraulic oil to the second hydraulic chamber via an opening-side solenoid valve and the opening-side pilot valve in that order; an accumulator configured to store hydraulic oil supplied from an oil collection tank via an oil collection tank outlet solenoid valve, the bidirectional auxiliary pump, and an accumulator solenoid valve in this order; and When performing a pressure accumulating operation to accumulate hydraulic oil in the accumulator, the control unit switches the oil collection tank outlet solenoid valve and the accumulating solenoid valve from a closed state to an open state with the closing-side solenoid valve and the opening-side solenoid valve closed, and performs control so that the bidirectional auxiliary pump sucks up hydraulic oil from the oil collection tank via the oil collection tank outlet solenoid valve, and the hydraulic oil sucked up by the bidirectional auxiliary pump is supplied to the accumulator via the accumulator solenoid valve. Hybrid servo system.

2. a displacement detection unit for detecting the amount of displacement of the guide vane; and The control unit is configured to determine whether or not the bidirectional control pump has a failure based on a result detected by a displacement detection unit regarding a displacement amount of the guide vane when the bidirectional control pump is driven. The hybrid servo system of claim 1 .

3. When the control unit determines that a failure has occurred in the bidirectional control pump and performs the closing operation of the guide vane, the control unit controls the closing pilot valve to switch the flow direction so that the hydraulic oil stored in the accumulator is supplied to the first hydraulic chamber, and the opening pilot valve to switch the flow direction so that the hydraulic oil is discharged from the second hydraulic chamber to the oil collection tank. The hybrid servo system of claim 2 .

4. Pressure switch that detects hydraulic oil pressure and The control unit is configured to determine whether or not the bidirectional auxiliary pump has a failure based on a result detected by a pressure switch regarding a pressure change amount of the hydraulic oil when the bidirectional auxiliary pump is driven. The hybrid servo system of claim 1 .

5. the control unit determines that a failure has occurred in the bidirectional auxiliary pump, and when performing the closing operation of the guide vane, performs control so that hydraulic oil is supplied from the bidirectional control pump to the first hydraulic chamber via the open-side pilot valve, and hydraulic oil is returned from the second hydraulic chamber to the bidirectional control pump.

5. The hybrid servo system according to claim 4.

6. When a sudden closing operation for closing the guide vane more rapidly than the closing operation is performed, the control unit controls the two-way control pump to supply hydraulic oil to the first hydraulic chamber via the close-side pilot valve, and switches the close-side solenoid valve and the open-side solenoid valve from a closed state to an open state, so that the two-way auxiliary pump supplies hydraulic oil to the first hydraulic chamber via the close-side solenoid valve and the close-side pilot valve in this order. The hybrid servo system of claim 1 .

7. When the supply of power to the hydraulic circuit unit is cut off due to a power outage and the closing operation of the guide vane is performed, the flow direction of the closing pilot valve is switched so that the hydraulic oil stored in the accumulator is supplied to the first hydraulic chamber, and the flow direction of the opening pilot valve is switched so that the hydraulic oil is discharged from the second hydraulic chamber to the oil collection tank. The hybrid servo system of claim 1 .

8. The bidirectional auxiliary pump includes: a first bidirectional auxiliary pump; a second bidirectional auxiliary pump; At least The closing solenoid valve is a first closing solenoid valve; a second closing solenoid valve; At least The opening solenoid valve is a first opening solenoid valve; a second opening solenoid valve; At least the first bidirectional auxiliary pump is configured to supply hydraulic oil to the first hydraulic chamber via the first closing-side solenoid valve and the closing-side pilot valve in that order, and to supply hydraulic oil to the second hydraulic chamber via the first opening-side solenoid valve and the opening-side pilot valve in that order, the second bidirectional auxiliary pump is configured to supply hydraulic oil to the first hydraulic chamber via the second closing-side solenoid valve, the first closing-side solenoid valve, and the closing-side pilot valve in that order, and to supply hydraulic oil to the second hydraulic chamber via the second opening-side solenoid valve, the first opening-side solenoid valve, and the opening-side pilot valve in that order. The hybrid servo system of claim 1 .

9. The oil collection tank outlet solenoid valve is a first oil collecting tank outlet solenoid valve; a second oil collecting tank outlet solenoid valve; At least The control unit When the pressure accumulating operation is performed using the first bidirectional auxiliary pump, the first oil collection tank outlet solenoid valve and the pressure accumulating solenoid valve are switched from a closed state to an open state with the first closing side solenoid valve, the first opening side solenoid valve, the second closing side solenoid valve, and the second opening side solenoid valve being closed, and control is performed so that the first bidirectional auxiliary pump draws up hydraulic oil from the oil collection tank via the first oil collection tank outlet solenoid valve, and the hydraulic oil drawn up by the first bidirectional auxiliary pump is supplied to the accumulator via the pressure accumulating solenoid valve, When the pressure accumulating operation is performed using the second bidirectional auxiliary pump, the second oil collection tank outlet solenoid valve and the pressure accumulating solenoid valve are switched from a closed state to an open state with the first closing side solenoid valve, the first opening side solenoid valve, the second closing side solenoid valve, and the second opening side solenoid valve being closed, and control is performed so that the second bidirectional auxiliary pump draws up hydraulic oil from the oil collection tank via the second oil collection tank outlet solenoid valve, and the hydraulic oil drawn up by the second bidirectional auxiliary pump is supplied to the accumulator via the pressure accumulating solenoid valve. The hybrid servo system of claim 8.

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