Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
  • F15B11/006—Hydraulic "Wheatstone bridge" circuits, i.e. with four nodes, P-A-T-B, and on-off or proportional valves in each link
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
  • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
  • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
  • F15B11/042—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in"
  • F15B11/0426—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in" by controlling the number of pumps or parallel valves switched on
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B19/00—Testing; Calibrating; Fault detection or monitoring; Simulation or modelling of fluid-pressure systems or apparatus not otherwise provided for
  • F15B19/005—Fault detection or monitoring
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
  • F05B2260/00—Function
  • F05B2260/70—Adjusting of angle of incidence or attack of rotating blades
  • F05B2260/76—Adjusting of angle of incidence or attack of rotating blades the adjusting mechanism using auxiliary power sources
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
  • F05B2260/00—Function
  • F05B2260/70—Adjusting of angle of incidence or attack of rotating blades
  • F05B2260/79—Bearing, support or actuation arrangements therefor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
  • F05B2270/00—Control
  • F05B2270/60—Control system actuates through
  • F05B2270/604—Control system actuates through hydraulic actuators
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
  • F15B20/002—Electrical failure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
  • F15B20/008—Valve failure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
  • F15B2211/21—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge
  • F15B2211/212—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge the pressure sources being accumulators
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/30—Directional control
  • F15B2211/305—Directional control characterised by the type of valves
  • F15B2211/3056—Assemblies of multiple valves
  • F15B2211/30565—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve
  • F15B2211/30575—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve in a Wheatstone Bridge arrangement (also half bridges)
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/30—Directional control
  • F15B2211/32—Directional control characterised by the type of actuation
  • F15B2211/327—Directional control characterised by the type of actuation electrically or electronically
  • F15B2211/328—Directional control characterised by the type of actuation electrically or electronically with signal modulation, e.g. pulse width modulation [PWM]
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/40—Flow control
  • F15B2211/405—Flow control characterised by the type of flow control means or valve
  • F15B2211/40576—Assemblies of multiple valves
  • F15B2211/40592—Assemblies of multiple valves with multiple valves in parallel flow paths
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/63—Electronic controllers
  • F15B2211/6303—Electronic controllers using input signals
  • F15B2211/6306—Electronic controllers using input signals representing a pressure
  • F15B2211/6309—Electronic controllers using input signals representing a pressure the pressure being a pressure source supply pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/63—Electronic controllers
  • F15B2211/6303—Electronic controllers using input signals
  • F15B2211/6306—Electronic controllers using input signals representing a pressure
  • F15B2211/6313—Electronic controllers using input signals representing a pressure the pressure being a load pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/63—Electronic controllers
  • F15B2211/6303—Electronic controllers using input signals
  • F15B2211/6336—Electronic controllers using input signals representing a state of the output member, e.g. position, speed or acceleration
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/665—Methods of control using electronic components
  • F15B2211/6656—Closed loop control, i.e. control using feedback
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
  • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
  • F15B2211/7051—Linear output members
  • F15B2211/7053—Double-acting output members
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/80—Other types of control related to particular problems or conditions
  • F15B2211/857—Monitoring of fluid pressure systems
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/80—Other types of control related to particular problems or conditions
  • F15B2211/86—Control during or prevention of abnormal conditions
  • F15B2211/862—Control during or prevention of abnormal conditions the abnormal condition being electric or electronic failure
  • F15B2211/8623—Electric supply failure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/80—Other types of control related to particular problems or conditions
  • F15B2211/86—Control during or prevention of abnormal conditions
  • F15B2211/863—Control during or prevention of abnormal conditions the abnormal condition being a hydraulic or pneumatic failure
  • F15B2211/8636—Circuit failure, e.g. valve or hose failure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/80—Other types of control related to particular problems or conditions
  • F15B2211/87—Detection of failures
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/80—Other types of control related to particular problems or conditions
  • F15B2211/875—Control measures for coping with failures
  • F15B2211/8752—Emergency operation mode, e.g. fail-safe operation mode
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/80—Other types of control related to particular problems or conditions
  • F15B2211/875—Control measures for coping with failures
  • F15B2211/8755—Emergency shut-down

Definitions

• the present invention relates to a system for control of a hydraulic system primary for pitch control of at least one rotor blade for a windmill, which system comprises at least a pressure source, which pressure source through valves are connected to at least a first port in an actuator, which actuator comprises a first and a second volume, which first and second volume is separated by a piston, which piston is fastened to at least one shaft, which shaft is connected to at least one rotor blade, which pressure source is connected to at least a common inlet to first group of valves, where each valves in the first group is connected to the pressure source through flow reductio means, which flow reduction means has a different size, which first group of val ves are connected to a common outlet, which common outlet is connected to the first port of the actuator, which first port of the actuator is further connected through different flow reductions to a second group of valves, which second group of valves are connected to the tank.
• EP 1835174 discloses an electro hydraulic control unit for rotor blade adjustment of a wind farm via a hydraulic cylinder.
• the hydraulic cylinder has one piston chamber and one piston rod chamber.
• Via an inflow valve assembly a pressure fluid connection can be established between the pump and the piston chamber, while via an outflow valve assembly, a pressure fluid connection can be established between the piston rod chamber and the tank.
• Each valve assembly has at least tw r o parallel-connected switch valves, which open and can be closed in various combinations in order to establish a desired position of the hydraulic cylinder. This control unit makes precise regulation of the rotor blade possible.
• the object o the invention is to achieve a reliable system for pitch control with extreme long meantime between failures.
• a further object is to achieve an emergency position of the valves for soft shut down of a wind mill.
• the object can be fulfilled if the first group of valves comprises at least one Normal Open valve and at least one Normal Closed valve, which second group of valves are Normal Closed (NC) valves.
• the first group of valves comprises at least one Normal Open valve and at least one Normal Closed valve, which second group of valves are Normal Closed (NC) valves.
• NC Normal Closed
• I Icrcby is achieved that normal pitch regulation can be performed by a number of on/off valves which probably can be Pulse With Modulated* PW ⁇ 1). In that way can be formed normal operation of the pitch control up and down in pitch angle in the same way as traditional proportional valves can perform operation.
• an automatic adjustment towards feather pitch will be achieved by pressure hydraulic accumulators where the pressure is transmitted through valves, which by their design in Normal Open and Normal Closed, automatically defines the degree of flow towards the lowest pitch possible.
• valves By more or less continuous operation of the valves with rapid switching on and off, it can be avoided that the valves are blocked with failure at the moment they have to be regulated. Because the valves are more or less continuous in movement, even if it is very slight movement of the valves and only very short periods for opening and closing, a continuous regulation can be formed where adjustment will take place, because the valves are so fast operating, but the flow is under control of the system so it is avoided that a valve is closed or maybe open for a longer period where there is a risk of blocking of the valve function. 1 Iereby is achieved an extremely reliable system.
• the pressure source be connected directly to the second port in the actuator to the second volume of the actuator.
• This second volume also comprises the shaft, therefore this actual pressure area inside the cylinder is reduced in relation to the first volume. Therefore, increasing pressure in the first volume up to a pressure equal to the pressure in the second chamber will automatically lead to a movement of the piston inside the cylinder and thereby also moving of the shaft. Full pressure in both chambers will in the system lead to feather pitch for the wing that is connected.
• the first flow reduction for the first valve of the first group of valves has a first opening, which second flow reduction for the second valve has a lager flow opening, which third flow reduction for the third valve has a lager flow opening than the second flow reduction which fourth flow reduction for the fourth valve is larger than the third flow reduction.
• a digital regulation of the valves is possible where for example three valves will lead to eight combinations, four valves will lead to 16 combinations, five valves to 32 combinations and so on, just as known from digital systems. But in combination with, for example, PWM regulation it is possible to achieve a very precise regulation of the valves. Depending on the speed of which regulation has to formed, the correct valve combination can be selected.
• valves with a very limited flow will be used, but if a rather fast regulation is required then valve combinations, maybe all the valves at the same time, will be opened.
• a good regulation can be performed if fast regulation is performed maybe up to 80 % of the result and the last 20 % is performed in a slower rate by modulating only the smaller valves.
• the numbers of combinations that are possible by for example PWM and digital valves are impossible to describe totally, but the number of flow combinations can be enormous.
• first flow reduction for the first valve of the second group of valves have a first opening, which second flow reduction for the sec- ond valve has a lager flow opening, which third flow reduction for the third valve has a lager flow opening than the second flow reduction which fourth flow reduction for the fourth valve is larger than the third flow reduction.
• valves the first group and the second group of valves be fast operating valves, which valves are controlled from the system.
• the use of extremely fast operating valves makes it possible to use other modulation forms than PWM. Instead of modulating the width of the pulses, it is possible simply to adjust the number of pulses just as one example of another modulation form.
• a fall-back operation be performed in case of a single valve failure in one of the valves where the flow is PWM controlled in the other valves to achieve same flow as through the failed valve.
• the system can be programmed so that this valve then is programmed not to be used and probably will end up in a closed sit- uation where the system automatically adjusts the regulation of the other valves so that normal operation of the pitch control is possible, but maybe extremely fast regulation is no longer possible. This is not the perfect way of operation of a system, but it is the possibility of operating system in a short period until maintenance is possible.
• valves be incorporated into the housing of the actuator. It is possible that the housing of the actuator is constructed in such a way that the valve groups are integrated in the housing of the actuator. In that way, this invention can be used without any tubing from the valves into the actuator. This can be very important in windmills where the whole pitch control system is part of the rotating rotor of the windmill.
• the flow reductions be formed as orifices, which orifices are integrated in the valves.
• a single bank of 2/2 valves can be used to operate a pitch in regenerative operation by use of a pilot-to-open and pilot-to-close valve for selecting direction of movement.
• a pilot-to-open and pilot-to-close valve for selecting direction of movement.
• the pending patent application further concerns a method for operating a pitch control system as previous described which method concerns at least the following sequence of steps.
• d the system performs measurement of the pressure in the second chamber of the actuator.
• the system based on input from a number of sensors can calculate the function of the valves and automatically get information about valve functions so that more functional valves will be indicated by the analysis of the input values.
• a total regulation system for the pitch of a windmill wing Of course there will be input to the system from the other controlled systems of a windmill so that a request from change of pitch also will take part of the regulation of the system. Therefore, an input or a request for a new pitch will automatically be accepted and regulation will be performed with the method as described.
• the valves are to be used to achieve a controllable variable emergency stop speed-contribution.
• Normal Open and Normal Closed valves it is possible to define a flow path in an emergency situation that will result in a controlled slow pitch regulation.
• a too fast pitch regulation can generate forces at a windmill, tower that can lead to the collapse of the tower. Therefore, it is very important that in a situation where an emergency occurs, the pitch regulation is performed at a relatively slow regulation where the change of pitch angle per minute is controlled by the combination of Normal Open/Normal Closed valves.
• valves of the first and the second group are used to achieve a controllable variable emergency stop function.
• the emergency flow path is generated through the normal regulation valves.
• these valves are typically during continuous operation always operational and a controlled flow path can be generated through the valves.
• the groups of valves are used to operate the pitch actuator in a closed loop position control. Based on feedback from pitch regulation in a windmill, it is possible by this system to perform a closed loop position control.
• the groups of valves are used to operate the pitch actuator in closed loop position and speed control.
• Fig. 1 shows a first possible embodiment of the system 2.
• Fig. 2 shows an alternative embodiment of the system 102.
• Fig. 1 shows a system 2 which indicates a pressure source 4 which could be a hydraulic pump and a hydraulic tank 6 where the pressure source could be connected to the tank 6 by pumping means.
• a flow line 8 connects pressure from the pressure source to a valve group 9 which valve group comprises a first flow reduction, 10 which is connected to a normally closed valve 12 from which valve 12 the hydraulic high-pressure liquid can flow to a line 26 towards the first chamber of the hydraulic actuator 29 through a port 28.
• flow reduction 14 connected to the normally closed valve 16.
• further valves are indicated and flow reduction 18 which is cooperating with the normally open valve 20.
• flow reduction 22 connected to valve 24 which valve 24 is a normally closed valve.
• the output from all four valves of the valve group 9 are, as already mentioned, combined into the flow line 26 which is connected to the first port 28 of the hydraulic actuator 29 where liquid is flowing into the pressure chamber 13.
• the hydraulic actuator further comprises a piston 31 which is connected to a shaft 33. At the other end of the piston 3 1 a second pressure chamber 32 is indicated. Through a terminal 34 this pressure chamber is in flow connection with a line 36 which is connected directly to the pressure line 8. Further through a line 38 the first pressure chamber 13 is connected to a second valve group 39.
• This valve group also comprises four different valves with each having its own flow restriction.
• the first flow restriction 40 is connected to a normally closed valve 42. Through a line the valve 42 is connected directly to the tank.
• a flow reduction 44 and normally closed valve 44 are indicated. Further, and in parallel to the first two valves, a flow reduction mechanism 48 and normally closed valve 50 are indicated. Further flow reduction mechanism 52 is indicated which is connected to the normally closed valve 54. The line 56 is directly connected to the tank 6.
• FIG. 1 shows a flow regulation means 58 and a variable flow reduction 60.
• Further pressure sensors 62 arc indicated and there are indicated pressure accumulators 64 and 66.
• the pressure in the chamber 30 will be regulated by pulse with modulation of the val ve in the valve groups.
• the valves in the valve groups are forming digital valves whereby each of the valve groups 9 and 39 can be adjusted into 15 different flow situations and a closest situation. Together with pulse modulation or other types of modulation of the valves, it is possible to perform a very precise regulation. By nearly continuous operation of the valves, it is possible always to know if the valves are operating correctly due the to the different flow sensors which already exist in the system, e.g. by measuring the pressure in the chamber 30 or the chamber 32. Small changes pressure can be performed with a very limited movement of the piston 31. But even very small changes in pressure are enough to indicate that the valves are operating as expected.
• Fig. 2 shows a system 102.
• This system comprises a pump 104 and a tank 106 with only one valve group 109.
• the valve group 109 comprises a flow restriction 1 10 which is connected to the normally closed valve 1 12 where, in parallel to the first valve and the first flow reduction mechanism, a further flow reduction mechanism 1 14 is indicated which is connected to the normally closed valve 1 16.
• the valve group 109 further comprises flow restriction 1 18 and normally open valve 120. Further flow re- duction 122 and normally closed valve 124 are indicated.
• a line 126 connects to the first terminal 128 of an actuator 129. Therefore pressure delivered from the valve group 109 is delivered into a pressure chamber 130.
• a piston 131 separates the actuator between a first pressure chamber and the pressure chamber 132.
• the second terminal 134 is connected by line 136 directly to the pressure source 104. Further in fig. 2 a pressure regulation mechanism 158 and a variable flow restriction mechanism 160 are indicated. Further a pressure indicator 162 and pressure accumulators 164 and 166 are indicated. Further a switching valve 163 is indicated which valve is able to control the opening of all valves 168 and 166. Hereby it is achieved that the valve group 109 can be changed from regulation from the pump to regulation towards the tank by means of the valve 163.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Wind Motors (AREA)

Applications Claiming Priority (4)

Publications (1)

Family

ID=47678442

Family Applications (1)

Country Status (2)

Cited By (7)

Citations (4)

• 2012
  • 2012-09-17 DK DKPA201270573A patent/DK201270573A/da not_active Application Discontinuation
• 2013
  • 2013-01-25 WO PCT/DK2013/050024 patent/WO2013113317A1/fr not_active Ceased

Patent Citations (4)

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