Hydraulic system for pitch angle adjustment of a rotor blade of a wind turbine and wind turbine with such a hydraulic system

A hydraulic system for adjusting the pitch angle of a rotor blade of a wind turbine, the hydraulic system comprising a variable displacement pump, a hydraulic accumulator, a dynamic valve, a proportional control valve, a tank and a pitch cylinder,

• wherein the variable displacement pump is connected to the control valve via a first connecting line without rotary feedthrough and the control valve is connected to the tank via a second connecting line without rotary feedthrough and the control valve is connected to a piston side of the pitch cylinder via a third connecting line without rotary feedthrough and the control valve is connected to a rod side of the pitch cylinder via a fourth connecting line without rotary feedthrough,
• so that in a first switching position of the control valve the first connecting line is connected to the third connecting line, and
• so that in a second switching position of the control valve, the first connecting line is connected to the fourth connecting line and the second connecting line is connected to the third connecting line,
• wherein the hydraulic accumulator is connected to the first connecting line via a fifth connecting line, in that the fifth connecting line opens into the first connecting line at a junction,
• wherein the dynamic valve is disposed in the fifth connecting line, and
• wherein the dynamic valve blocks the fifth connecting line in the direction of flow from the hydraulic accumulator to the first connecting line and only the variable displacement pump is connected with the control valve in a first switching position of the dynamic valve and the dynamic valve releases the fifth connecting line in a second switching position of the dynamic valve, wherein the variable displacement pump and hydraulic accumulator are connected to the control valve in the second switching position of the dynamic valve.