The composition of the wind turbine hydraulic system
Wind power hydraulic system
The fan has many rotating parts. The cabin rotates in the horizontal plane and keeps up with the wind. The wind wheel rotates along the horizontal axis to generate power. In a pitch fan, the blades that make up the wind wheel are rotated about the central axis of the root to accommodate different wind conditions. At the time of shutdown, the tip of the blade is pulled out to create damping. The hydraulic system is used to adjust the blade pitch, damping, stop, brake and other conditions.
1, the drive system
The wind turbine uses two drive systems, namely the brake system (deflector and spindle-high-speed shaft swing system) and the blade angle control and the cabin deflector swing control system. The brake system is hydraulically controlled, while the blades and deflectors are controlled hydraulically or electrically. The argument for using that type of transmission is no exception in the design of wind turbines. The output power, speed or frequency response of the blade angle, whether hydraulic or electrical, is generally determined by the manufacturer's experience.
2, pitch control system
The blade angle (pitch) control system should be designed mainly when the wind turbine encounters strong wind such as typhoon, the unit can immediately stop running, so that the power supply is interrupted, and the blades need to be controlled in parallel with the wind direction. On the top, make sure that the blades are no longer rotating. After the power supply is interrupted, the energy storage system of the unit starts to work, such as hydraulic accumulators or batteries. When hydraulic control is used, a hydraulic linear actuator (hydraulic cylinder) is used, and when it is electrically controlled, an electric rotary actuator is used. The hydraulic linear drive mounted in the spindle and the accumulator applied during stop are also mounted in the shaft.
The foreign hydraulic linear actuator is a hydraulic linear actuator (Electro-hydraulic system) that combines the advantages of hydraulic, electronic and electrical, referred to as the Hybrid system. The energy saving of this system is worthy of promotion.
The integrated electro-hydraulic servo drive system consisting of hydraulic cylinder, hydraulic pump, AC motor, accumulator, solenoid valve, sensor and power source has the advantages of good dynamic performance, large output power, good electrical installation and maintenance. . It can reduce the shortcomings of the hydraulic system, such as the impact of oil leakage and oil pollution, so that the reliability is significantly improved, and when the power is interrupted, it can fully demonstrate the advantages of the hydraulic transmission, that is, the hydraulic cylinder in series with the hydraulic cylinder. The accumulator is supplied with oil so that the windward side of the blade is parallel to the wind direction, so that the impeller stops rotating. The hydraulic system is directly supplied by the hydraulic cylinder with position sensor and the gear pump with two-way oil supply. There is no valve in the middle, which reduces the pressure loss and the oil leakage point. This system is more than 40% more energy efficient than the servo control system.
In addition to the above-mentioned Hybrid system, in foreign countries, the blade angle control and the deflector rotation also adopt a linear electro-hydraulic servo proportional hydraulic cylinder and a rotary hydraulic proportional servo drive motor. These systems have the advantages of good dynamic and static performance and long life, but they are inferior to the Hybrid system in terms of energy saving and oil pollution.
