Different Method Of Speed Control For Maximum Power In WIND Turbine

Importance of Variable Rotor Speeds

For the Speed control one of the important is variable rotor speed.

Rotors reach high efficiency having minim no. Blade.

In this picture show that the rotor efficiency denoted by Cp. Rotor efficiency depend upon the tipspeed ratio in short form TSR.  The best TSR is consider the around about 4-6(simply when blade of wind turbine moves 4-6 times of air velocity). As the velocity of the air rotation of blades change.

Show blade efficiency directly proportional to the wind speed.

Graph show that the effect of rpm and plotted between wind speed and blade efficiency. Hence clearly show the effect speed of the rotor with respect of Cp(blase efficiency) 

Here its show that when the rotor speed increase (20-30,30-40) the electric power also increase. 

Pole-Changing Induction Generators

For this method we can control the speed of generator or motor. No of pole play important role for controlling the speed. In the induction generator poles located on stater and from external connection we can change the speed of generator with out changing in the rotor.

3600 rpm produced when the frequency 60 Hz and no. Of poles is 2.

A number of house holed devices such as exhaust fan, washing machine can be ran in different speed using pole changing phenomena.  

Multiple Gearboxes

We can also control the speed by using the more then gear boxes. For example we use two gear box each of gear box attach separate generator. Combination form like that a gear box for low wind speed connected to generator 2nd gear box designed for high wind velocity plus generator.

Indirect Grid Connection Systems 

When speed of wind change the movement of blade change with respect to wind. When the synchronous or induction generator produces extra energy then how we can handled it.

we can add this extra energy to the grid system but we can’t add this directly because frequency factor involve. Our grid system has 50 -60 HZ energy but the output of generator we don’t have same frequency. A process given below in the figure to add this energy in the grid system.

Rectifier, inverter and filter to reach 50 or 60 Hz frequency

In the above section we talk about higher level energy section but if we have a small energy production system like 5 to 10 kw then.

We can control the speed and save the energy. We can control speed by adding extra load. When we add this the more load generator required more rpm and the wind turbine due to load slow down.

If we add extra battery bank then store this energy and utilize after all.