Wind power generation, there are generally two types of wind turbines, horizontal wind turbines (the main axis is installed vertically) and vertical wind turbines (the ones usually seen spinning all the time)
The latter are more common is applied, the former is generally only used on small windmills.
The windmill blades rotate after being blown by the wind. When it reaches a certain speed, the measuring part measures whether the speed is sufficient. . Because at this time, when the windmill rotates, it drives The gear phase (specifically, an accelerating gearbox) is used to slightly increase the speed
Then behind it finds an asynchronous generator
This causes asynchrony. generator to spin faster., the larger the current, the slower the current, the lower the current. When the speed is too low, the detection circuit detects it and then separates the connection between the generator and the power grid, because if it does, the detection circuit detects it. is not separated, the generator rotor speed is lower than the synchronous speed, and it becomes a motor
An asynchronous generator is actually an asynchronous motor, there is no difference.
In addition, wind turbines produce electricity due to the nature of asynchronous generators. Large wind turbines usually have an inverter power supply to initialize the rotating magnetic field of the generator, while some rely on synchronous generators, but most of them. come from the transmissionon of reverse power from the power grid
That is, when the speed reaches a certain level, that is, once the speed is higher than the synchronous speed , the three-phase power supply is connected to the generator, and the power grid sends power to the generator. Since the rotor rotates at a speed higher than the synchronous speed, when rotating it does not consume active power but consumes reactive power, but it emits active electrical energy and then generates electricity .< /p>
It should be noted that the asynchronous generator must require an external power supply to initialize it.
< p>This is to allow it to establish a rotating magnetic field, otherwise it will not cannot produce electricity, but if its external power supply is 220V50HZ, then as long as its speed exceeds the synchronous speed, the faster it rotates, the more current it outputs. The higher the voltage and frequencylarge, the voltage and frequency will not change and are consistent with the electrical network which gives it the initial power.
The concept of semi-direct drive is a combination of Direct drive and double feedback
< p>strong>Wind turbinesare caused by the problems encountered in the large-scale development process, taking into account the characteristics of both.
The difference between a semi-direct drive wind turbine and a direct drive wind turbine:
1. The principles of the two are different,
1. A direct drive wind turbine is a generator directly driven by the wind, also known as a gearless wind turbine. This generator is driven by a multi-pole motor directly connected to the turbine, eliminating the need for a traditional component such as a multi-pole motor. a gearbox.
2. The driven wind turbinet semi-direct adopts single-stage or double-stage speed-increasing gearbox, multi-pole synchronous generator and full-capacity converter. In addition, in order to reduce the weight of the machine room, semi-direct drive wind turbines are mostly compact designs, that is, the low-speed shaft is eliminated or the length of the low speed shaft is reduced. The speed is reduced, and the output shaft of the speed increasing box is directly connected to the main shaft of the generator.
2. The advantages of both are different
1. The direct drive wind turbine has no gearbox, which reduces transmission losses and improves power generation efficiency, especially in low conditions. wind speed environments, the effect is more significant.
2. The semi-direct drive generator rotates at high speed. This characteristic determines that the trainingsemi-direct ent can on the one hand improve the reliability and service life of the gearbox, at the same time as direct drive generators, it can take into account the corresponding design of the generator and improve the design conditions and Manufacturing. of high power direct drive generators.
3. The structures of the two are different.
1. The direct drive wind turbine uses a multi-pole motor directly connected to the turbine for drive, eliminating the need for a gearbox part. Since the gearbox is a component that is easily overloaded and has a high rate of premature damage in megawatt-level wind turbines, there is no direct drive wind turbine without a gearbox.
2. The concept of semi-direct drive arose from problems encountered in the development of large-scale direct-drive, dual-fed wind turbines.scale, taking into account the characteristics of both. Structurally speaking, the semi-direct drive is similar to the double-feed drive and has the characteristics of various configuration forms. At the same time, the pinless structure under current research also has a similar appearance to the direct drive.
The above content refers to Baidu Encyclopedia - Semi-direct drive wind turbine
The above content refers to Baidu Encyclopedia - Direct drive wind turbine