Variable flow hydraulic circuit for a wind turbine

A hydraulic circuit for a wind turbine, the hydraulic circuit comprising:

• a fixed displacement pump including a suction input and a delivery output;
• a pump motor for driving the fixed displacement pump;
• a pressure line hydraulically connected to the delivery output of the fixed displacement pump for delivering an output flow and/or an output pressure generated by the fixed displacement pump towards at least one consumer circuit;
• a bypass valve including a valve input hydraulically connected to the delivery output of the fixed displacement pump;
• a reservoir hydraulically connected to the suction input of the fixed displacement pump;
• and
• a return line for receiving a return flow from the at least one consumer circuit, the return line being hydraulically connected with the bypass valve and the reservoir,
• wherein the bypass valve includes a variable opening for controlling the output flow or the output pressure delivered by the fixed displacement pump towards the at least one consumer circuit, and
• wherein the bypass valve is a proportional valve and the hydraulic circuit further comprises a relief valve in parallel with the bypass valve for connecting the delivery output of the fixed displacement pump with a reservoir when a predefined relief pressure is reached in the pressure line.