Doubly-fed: Doubly-fed motor has low cost and mature technology; The capacity required by the power electronic converter is small; Can be in Xiao Rong
Under the condition of quantity, all air cooling is adopted;
Direct drive: it can generate electricity in a very wide wind speed range; The three-stage planetary gear box of 1: 80 is omitted, which has high reliability and maintainability.
Good sex; Power electronic conversion device does not need active Crowbar；; The power factor is almost infinite.
It can be regarded as a reactive power generator hanging on the power grid.
Disadvantages:
Doubly-fed: The wind speed range required for power generation is too high, generally within +20%-20% of the synchronous speed, and the power generation capacity.
Limited, easy to off-grid, poor economy and stability of power generation; There is a three-stage planetary gearbox, which takes five years.
Replacing it once, the maintenance cost is very high (this thing is on the tower, think about maintaining it at an altitude of more than 70 meters)
A ton of things); There is also an active crowbar, which is extremely technically difficult and is now the same all over the world.
ABB's family is completely finished; The adaptability of the power grid is poor and the power factor is limited, generally only to 0.9.
Direct drive: direct drive and power electronic devices are expensive; The direct driver's technology is immature; In order to keep the wind speed straight when it is very low
The driving motor can generate electricity, which leads to many stages of the motor, generally more than 100 pairs, which makes the motor body
The product is very large; Only water cooling, this thing is too much trouble.
Outlook:
Doubly-fed: the poor economy and stability of power generation and the poor adaptability of power grid determine that wind power has no future development.
Perhaps AC excitation of hydraulic turbine is its development direction.
Direct drive: it has no fatal shortcomings and is the mainstream technology in the future. In fact, Europe has shown this trend.
Conclusion:
Direct drive is better than double feed.
Personally, I think the best technology is hybrid direct drive, and using a small proportion gearbox can balance the speed increase.
The life of gearbox and the volume of motor.
I think Goldwind has a good eye in the field of wind power, and it is a good idea to skip the doubly-fed direct drive directly. In addition, the golden wind
In 2004, he began to apply for the patent of permanent magnet motor, and the layout was good.
Power grid connection mode:
Doubly-fed: There are two main ways of grid connection: isolated island and no-load grid connection. The key is to adjust the stator voltage caused by rotor excitation.
The grid voltage meets the grid-connected conditions.
Direct drive: as long as the inverter output voltage and grid voltage meet the grid-connected conditions.