| 摘要 |
A renewable energy extraction device, such as a wind turbine generator includes a turbine 2 driving a hydraulic pump 10 which drives a variable displacement hydraulic motor 14 that drives an electrical generator having a rotor. The hydraulic motor 14 has electronically controlled valves, which may regulate flow between a high and low pressure manifolds, and are operated to select a net displacement of working chambers of the motor 14 on each cycle. In an event of an electric grid fault causing a maximum absorbable torque of the electrical generator to collapse, the electronically controlled valves are controlled to reduce a rate of displacement of working fluid by the hydraulic motor 14, thereby rapidly reducing the torque exerted on the generator rotor. Excess fluid displaced by the pump 10 is stored in an accumulator 28. When a maximum amount has been stored fluid is discharged through a throttle. If the fault persists, the turbine blades are feathered to reduce power input. |
