CONTROL UNIT FOR ROTOR BLADE ADJUSTMENT

Abstract

In an electrohydraulic 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 two 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.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a rotor blade adjuster with an electrohydraulic control unit in the first exemplary embodiment of the present invention;

FIG. 2 shows a rotor blade adjuster with an electrohydraulic control unit in the second exemplary embodiment of the present invention; and

FIG. 3 shows a rotor blade adjuster with an electrohydraulic control unit in the third exemplary embodiment of the present invention.

Claims

1. An electrohydraulic control unit for rotor blade adjustment of a wind farm, comprising a hydraulic cylinder having a piston chamber and a piston rod chamber; an inflow-side valve assembly for establishing a pressure fluid connection between a pump and said piston chamber; an outflow-side valve assembly for establishing a pressure fluid connection between said piston rod chamber and a tank; said inflow valve assembly having at least two parallel-connected switch valves, and said outflow valve assembly having at least two parallel-connected switch valves, and said at least four switch valves being triggerable in different combinations for establishing a desired position of said hydraulic cylinder.

2. An electrohydraulic control unit as defined in claim 1, wherein said at least two parallel-connected switch valves of said inflow assembly have a different maximum flow volume, while said at least two parallel-connected switch valves of said outflow valve assembly have a different maximum flow volume as well.

3. An electrohydraulic control unit as defined in claim 1, wherein said switch valves are electrically actuated seat valves.

4. An electrohydraulic control unit as defined in claim 2, wherein said switch valves are configured so that the maximum flow volume of said switch valves associated with an inflow and an outflow, respectively, differ.

5. An electrohydraulic control unit as defined in claim 4, wherein said maximum flow volumes of said switch valves associated with the inflow and the outflow differ by a factor of 2.

6. An electrohydraulic control unit as defined in claim 1, wherein said inflow valve assembly has three parallel-connected switch valves, and said outflow valve assembly has three parallel-connected switch valves, wherein maximum flow values of the respective ones of respective three parallel-connected switch valves have a ratio 4:2:1.

7. An electrohydraulic control unit as defined in claim 1, wherein said inflow valve assembly has four parallel-connected switch valves and said outflow valve assembly has four parallel-connected switch valves and maximum flow volumes of respective four parallel-connected switch valves have a ratio of 8:4:2:1.

8. An electrohydraulic control unit as defined in claim 1, wherein said piston rod chamber is in pressure fluid connection with the pump upstream of said inflow valve assembly; and further comprising means for providing the pressure fluid connection between said piston rod chamber and the pump upstream of said inflow valve assembly.

9. An electrohydraulic control unit as defined in claim 1; and further comprising a field bus, said switch valves being triggerable by said field bus via a pulse width modulated current.

10. An electrohydraulic control unit as defined in claim 9, wherein said field bus is configured as a CAN bus.