Modern wind turbine and modern wind turbine design
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The wind turbine introduced on this website is a machine that converts phoenix energy into electrical energy, which is different from the “windmill” that converts wind energy into mechanical energy. As generators, wind turbines are connected to the power grid. These networks include battery charging circuits, power supply systems in residential areas, isolated or regional power grids, and large regional public power grids. In terms of the total number of wind turbines, most of the power is small, 10kW or less; in terms of total power generation capacity, the capacity of wind turbines is quite large, ranging from 1.5 MW to 5 MW. Most of the wind turbines are used in public power grids, and most of them are in Europe and the United States. Recently, they have also appeared in China and India.
If you want to know how to use a wind turbine, here is a brief introduction to some basic knowledge of wind turbine operation. In modern wind turbines, the actual energy conversion process uses aerodynamic lift to generate a positive torque on the shaft. It first generates mechanical energy, and then Converted into electrical energy in a generator. The wind turbine is different from other generators. It can only convert the wind energy obtained at the time into usable energy, but it cannot be stored for subsequent use. Therefore, the wind energy output of the wind turbine is fluctuating and cannot be dispatched (most wind turbines can What is done is to limit the production capacity so that it is lower than the energy produced by wind). Any system connected to a wind turbine must consider the instability of its power in a certain way. In larger power grids, the use of wind turbines can increase power generation and reduce the number of other traditional generators or their fuel usage in operation; in smaller power grids, there are energy storage equipment, backup generators and some Special control system to dispatch the load. Another fact is that wind energy cannot be transported: it can only be converted into energy where there is wind. Historically, wheat could be ground into flour at a windmill and then transported to its place of use; today, electricity can be transmitted via transmission lines, which to a certain extent makes up for the lack of wind energy transmission; in the future, an energy system based on hydrogen energy Increased this possibility.
This website focuses on the most commonly used horizontal axis wind turbine (HAWT). Its rotation axis is parallel to the ground. HAWT is usually classified according to the direction of the wind wheel relative to the tower; the upwind or downwind direction of the tower is determined by Lunyi The design is divided into: rigid or swing type. According to the control mode of the wind turbine blade, it is divided into: variable angle of attack or stall type. According to the number of blades, it is generally divided into two blades or three blades. According to the wind turbine, it is divided into: automatic deviation Sail or actively yaw. The picture shows the arrangement of wind turbines in the upwind and downwind directions.
The main subsystems of a typical land-based horizontal axis wind turbine include:
- The wind wheel is composed of blades and supporting wheels.
- The drive chain, which includes the rotating parts of the wind turbine (excluding the wind wheel), is usually composed of a rotating shaft, a gear box, a coupling, a mechanical brake device and a generator.
- The nacelle and main frame, which includes the wind turbine nacelle cover, bottom plate and yaw system.
- Tower and foundation. Wind turbine control system.
- Power system supporting equipment, including cables, switchgear, transformers and possibly required power electronic converters.
The main choices of wind turbine design and structure include:
- The number of blades (usually two blades or three blades).
- Wind wheel position: the downwind or upwind direction of the tower.
- Blade material, construction method and molding line.
- Wheel whip design: rigid, swing type or articulated type.
- Power control adopts pneumatic control (stall control) or variable blade angle of attack (angle of attack control).
- Constant speed or variable speed wind wheel.
- Wind wheel orientation (aligning to the wind direction) adopts self-orientation (free yaw) or direct control (active yaw).
- Synchronous generator or induction generator (squirrel cage or double-fed).
- Gear speed increase or direct drive generator.