Fixed-speed wind turbines are mainly equipped with squirrel-cage induction generators. Wind speed can vary. It will work as generator as long as speed of rotation is more than synchronous speed.
Why is it then called *fixed-speed wind turbines* even though the wind speed is variable?
The part that has a fixed speed is the generator. Its speed is fixed regardless of the blade rotation speed as long as that rotational speed is greater than that needed by the power transmission to achieve the minimum generator rotor speed.
That rotor is what is kept at a constant rate. The transmission is the key.
Do you mean fixed SPEED or fixed FREQUENCY? Although I do not have personal experience with a device with the name uyou mentioned, I think induction generator. I essence, it is an induction motor with negative slip. Synchronization is supplied from an external source. Excitation cannot come easily from the basic machine itself.
Bill
Don't they keep the blade speed constant as well and vary the pitch to match the wind?
There is a max blade speed, but one would think that pitch would be adjusted to maximize torque applied regardless of rotational velocity.
Just as the transmission converts whatever rotation to an output shaft speed that is constant for the generator.
So I would think there would be a minimum blade rotational speed before the transmission will even engage, and then a range or window of speeds thereafter that are sufficient for proper operation. Of course, there would be a max speed as well as those blades are some pretty big masses moving around. I am sure there is an optimal speed.
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