Bosch Rexroth Develops Hydraulic Pitch Drives for Wind Energy Turbines

Hydraulic pitch drives from Bosch Rexroth enable turbines to shift automatically with changes in wind velocity. As the wind grows stronger, the hydraulic pitch drives actively turn the rotor blades away from the wind so that the turbine can continue to generate the nominal output. In the event of storm or gusting wind conditions, the pitch drives can automatically secure the wind turbine, by bringing the rotor blades to the neutral 90-degree position for safety.

Wind turbine pitch drives reduce the forces that act on the basic structure and the mechanics of the wind turbine, protecting it from damage, excess wear and tear, and generator malfunction. In addition, low-maintenance Rexroth pitch drive technology lets wind energy plant operators control the output of wind turbine farms and adapt to changing power grid demand.

Wind turbine pitch drives are built from a combination of advanced Bosch Rexroth hydraulics integrated to meet the operating conditions of wind power generation. Advanced proportional valves control the hydraulic actuators, with communication between the turbine and the proportional valves occurring through current or voltage interface or directly via field bus.

Hydraulic pressure is provided by AA10VSO axial piston pumps with pressure controllers. Bladder-type accumulators developed specifically for wind turbine generators store sufficient energy for an emergency operation of the pitch control. The hydraulic control block is the central drive element and integrates all components in a modular assembly.