Wind energy is an abundant, clean, and renewable energy source that offers a clean, plentiful, safe, continuous, and stable energy supply. Wind power projects currently represent the primary means of harnessing wind energy and are receiving significant attention and rapid development worldwide. In wind power systems, the two main components are the wind turbine and the generator.

　　Adopting variable-speed, constant-frequency generation technology for wind turbines and variable-pitch control in wind power projects represent the prevailing trends in wind power technology and constitute its core technologies today. Let us now explore the development directions and key characteristics of wind power engineering.

　　I. Adjustment of Wind Turbine Slurry

　　Wind turbines capture wind energy through their rotor blades and convert it into mechanical torque acting on the hub. Variable pitch control adjusts the angle of the blade’s chord line relative to the oncoming wind and its longitudinal rotation axis, thereby influencing the lift and drag forces on the blade. This mechanism limits the increase in turbine output during high-wind conditions, maintaining a constant power output and resulting in a smooth power curve. Below the rated wind speed, the controller keeps the blade pitch angle near zero degrees, with no further adjustment—effectively equivalent to fixed-pitch operation.

　　By adjusting the blade pitch to maintain optimal aerodynamic performance, this type of wind turbine experiences significantly lower dynamic loads compared with other designs, thereby reducing material consumption and lowering the overall weight. Furthermore, variable-pitch wind turbines can effectively maintain the blade angle of attack at low wind speeds, resulting in superior power output relative to stall-regulated turbines; thus, they are particularly well suited for deployment in regions with low average wind speeds.

　　Another advantage of adjustable-tip-speed-ratio control is that, when wind speeds reach a certain threshold, stall-type wind turbines must shut down, whereas adjustable-tip-speed-ratio wind turbines can gradually transition to a full-blade-extension configuration with zero blade load, thereby avoiding shutdown and increasing the turbine’s energy output.

　　A drawback of pitch control is its high sensitivity to gusts. Pitch-regulated wind turbines exhibit relatively small power fluctuations caused by wind-induced vibrations, whereas variable-pitch wind turbines show larger fluctuations. This difference is particularly pronounced in constant-speed wind turbines that employ variable-pitch control; therefore, the yaw system must respond quickly enough to mitigate this effect.

　　II. Variable-Speed Constant-Frequency Wind Turbine

　　In wind power generation projects, AC-excited doubly-fed induction generators are commonly used. These generators adopt a structure similar to that of wound-rotor induction motors, with only slip rings and brushes on the rotor windings. As mentioned above, the rotor speed is dependent on the excitation frequency. Consequently, the internal electromagnetic relationships in a doubly-fed generator differ from those in both induction and synchronous generators, yet it exhibits characteristics of both types.

　　The amplitude of the excitation current can be adjusted to regulate reactive power; by adjusting the phase of the excitation current, the active power output can be controlled. With vector control, reactive power can be independently regulated, allowing the prime mover to operate at variable speeds within a certain range, thereby simplifying the speed-control equipment and reducing mechanical stress during speed regulation. At the same time, this approach makes unit control more flexible and convenient, enhances operational efficiency, and limits the portion of the electrical load requiring variable-frequency control to a fraction of the motor’s rated capacity, which in turn enables smaller, more compact VFDs, lowers costs, and reduces capital investment.

　　The foregoing outlines the development trends and key characteristics of wind power engineering. For more information, please feel free to contact us at any time!