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In order for wind turbines to convert mechanical energy into alternating current that meets grid standards, a wind energy conversion system must be configured.
Through the wind energy conversion system, the mechanical energy contained in the wind turbine with changing speed can be converted into stable alternating current consistent with parameters such as grid voltage and frequency. We call this energy conversion system a power generation system.
1. The principle of wind energy conversion system
The principle of the wind energy conversion system is to use wind power to drive the rotation of windmill blades, and then increase the speed of rotation through the speed booster to promote generator power generation.
Simply put, the wind energy conversion system is the process of converting wind energy into mechanical energy, and then converting mechanical energy into electrical energy. That is, wind power. This process does not require fuel or radiation, and does not produce air pollution, which is a clean energy source.
2. A brief introduction of wind power generation
The device required for wind power generation is called a wind turbine. A wind turbine is a device that converts wind energy into electrical energy. The principle is the wind drives the impeller to rotate.
And the impeller drives the generator to rotate and cut the magnetic induction line. Wind energy is converted into mechanical work, which drives the rotor to rotate and ultimately generates electrical energy.
3. Classification of wind turbines
- Horizontal axis wind turbine, the axis of rotation of the wind turbine is parallel to the wind direction.
- Vertical axis wind turbine, the axis of rotation of the wind turbine is perpendicular to the ground or the direction of airflow.
Modern wind turbines are mostly horizontal shaft type. Horizontal shaft wind turbines include blades, hubs (collectively called impellers with blades), nacelle covers, gearboxes, generators, towers, bases, control systems, braking systems, yaw systems, hydraulic devices, etc.
Its working principle is: when the wind flows through the blades, due to the effect of aerodynamic force driving the impeller to rotate, the impeller is connected to the gearbox through the main shaft, and the generator is driven to generate electricity after acceleration through the gearbox (or speed increaser).
4. What is a wind turbine
There are many types of power generation systems for modern large-scale wind turbines, and different wind energy conversion system companies choose different technical routes. They have developed and produced wind turbines with different types of wind energy conversion systems like offshore wind power.
As a result, we see wind turbines in wind energy conversion systems with different shapes and interiors. According to the type of transmission chain, the type of wind turbine can be divided into three categories: high speed transmission, medium speed transmission and direct drive.
● High speed transmission
It mainly includes dual-fed asynchronous power generation system and squirrel cage asynchronous power generation system, and the model is called dual-fed asynchronous generator set and squirrel cage asynchronous generator set.
● Medium speed transmission
Also known as semi-direct drive, the power generation system is a permanent magnet power generation system, and the model is called a semi-direct drive model.
● Low speed transmission
The low speed transmission power generation system is a permanent magnet power generation system, and the model is called a direct drive model.
Although there are many types of power generation systems, their core configuration is similar. The core components of the power generation system are generators and converters. Based on the difference in transmission chain structure and the difference between generators and converters, a variety of power generation systems have evolved and been successfully applied to wind turbines.
5. The core of the wind energy conversion system
One of the core components of the wind energy conversion system's power generation system is the generator. Wind power converts mechanical energy into alternating current through generators. Different generator types are suitable for different drive chain structure types.
Due to the unstable characteristics of wind, the alternating current frequency and voltage generated by the generator are unstable, so the power generation system needs to be equipped with another core component.
Another core component is the energy storage inverter. The wind energy conversion system converts the electrical energy emitted by the generator with unstable frequency and voltage into electrical energy with stable frequency and voltage that meets the grid standards.
Inverters mainly include full-power inverters and doubly-fed inverters. Different generator types need to be equipped with different inverters to achieve stable power generation quality, power generation control, torque control and other functions.
6. Difficulties in the practical application of wind energy conversion system
● The air volume is out of control
The most basic thing about wind power is wind. But wind power is different from solar energy and water power, although the energy contained is huge, but it is irregular.
The trajectory of high winds can be rerouted at any time, which is very troublesome to monitor. This makes it difficult to accurately select the location of wind farms, which can only be roughly extrapolated from past data. Even so, the output value is not guaranteed.
● Environmental impact
Although the wind energy conversion system does not produce radiation and air pollution, rotating wind turbines still have a great impact on the migration of birds. Moreoner, wind energy conversion system is still in the stage of industrial and commercial energy storage, and further development is needed from the application of home energy storage.
● Noise pollution
Theoretically, the decibel number of the fan is within the acceptable range for humans. But this is only theoretical, and there will be many differences in practical applications.
7. Conclusion
The above several power generation systems have their own advantages and disadvantages, different wind power companies according to their technology selection and cost and market judgment and other factors to select the type of power generation system, and develop the corresponding type of power generation system wind turbines.
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