**3. The main problem of wind power**

It is necessary to solve very serious problem for using windmills effectively [5–7]. The main problem of windmill's energy is the changing of the speed and the direction of wind flow. Thus, the windmill rotor rotates with a different speed and alternator gives the voltage with variable parameters of amplitude, frequency and phase (**Figure 6**). It is impossible to use this nonstandard energy. It is

**2. Various of the designs of wind turbines**

*Share of wind energy in the total balance of alternative energy.*

**Figure 3.**

*Aerodynamics*

**Figure 4.**

**6**

*Different designs of wind wheels and their efficiency.*

• wind turbines of low power (up to 10 kW);

• wind turbines of average power (from 10 to 100 kW);

Wind turbines can be classified into the following types by output power

**Figure 6.** *Illustration of wind turbine operation.*

necessary to transform the nonstandard energy to the energy with standard parameters [4, 8–18].

In practice some methods to solve this problem are known.

1. Application of asynchronous (induction) alternator.

**Figure 7** shows the design of the inductor alternator. The disadvantages of this method are:


**Figure 9** shows the design of the double fed alternator.

*winding; 5, electronic control system; 6, rotating magnetic field; 7, Stator 3 phases winding).*

devoted to the description of this promising wind turbine.

power plants. The design has a Russian patent. It is described below.

**4. The application of the DFIA**

**Figure 8.**

**Figure 9.**

**9**

*Design of the synchronous alternator.*

*DOI: http://dx.doi.org/10.5772/intechopen.89255*

This type of alternator can transform the nonstandard energy into standard energy without complex units and without additional stages of energy conversion. This is a new approach to solving the problems of wind energy. This Chapter will be

*Design of the asynchronous synchronous alternator (1, wind turbine; 2, rotor; 3, Stator; 4, rotor; 3 phases*

*Application of an Asynchronous Synchronous Alternator for Wind Power Plant of Low, Medium…*

It is well-known the principle of operation of the double-fed alternator [12, 14–16]. Electric machine of this type has been studied by scientists around the world since 1960. It has different applications, but in wind power it is used only for the last 10 years. The authors offer a unique design that they have developed for a row of wind

The alternator consists of two electric machines. The main electric machine is a power alternator. It is the induction machine with a phase rotor. So, the stator and the rotor have three phase windings. The alternator has the inverse design. It means that the rotor is settled outside of stator. It is very comfortable for the windmill because it is possible to attach the blades to the rotor. The three phase rotor winding is supplied by an adjustable voltage source. The rotor creates the rotating magnet field. This magnet field generates the voltage in the stator winding. If the rotor is fixed the speed of rotation of magnet field depends only from frequency of voltage source. But if the rotor begins to rotate, the speed of magnet field is added to the speed of rotor rotation. So, the total speed of magnet field is combined with two parts. We can change the frequency of the adjustable three phase voltage sources. When the speed of rotor is variable we can choose the necessary frequency of voltage source and we will have the stable frequency in the stator winding. In this

2. Application of permanent magnet synchronous alternator with rectifier and invertor.

**Figure 8** shows the design of synchronous alternator. The disadvantages of this method are:


**Figure 7.** *Design of the inductor alternator.*

*Application of an Asynchronous Synchronous Alternator for Wind Power Plant of Low, Medium… DOI: http://dx.doi.org/10.5772/intechopen.89255*

**Figure 8.** *Design of the synchronous alternator.*

**Figure 9.**

necessary to transform the nonstandard energy to the energy with standard

• It is necessary to supply the reactive energy for working of the induction alternator. Such windmills can work only with electric grid or with battery of

• When induction alternator works with electric grid it uses the reactive power

2. Application of permanent magnet synchronous alternator with rectifier and

• They are many stages for transforming the nonstandard energy to standard energy (the rectification, the stabilization, the inversion). Every stage has his

3. Application of an asynchronous synchronous alternator (double fed inductor

In practice some methods to solve this problem are known.

1. Application of asynchronous (induction) alternator.

**Figure 7** shows the design of the inductor alternator.

**Figure 8** shows the design of synchronous alternator.

• The equipment for this method is very expensive.

own loses and efficiency. So, the total efficiency is very low.

The disadvantages of this method are:

and makes parameters worse.

The disadvantages of this method are:

parameters [4, 8–18].

*Illustration of wind turbine operation.*

**Figure 6.**

*Aerodynamics*

capacitors;

invertor.

alternator) (DFIA)

*Design of the inductor alternator.*

**Figure 7.**

**8**

*Design of the asynchronous synchronous alternator (1, wind turbine; 2, rotor; 3, Stator; 4, rotor; 3 phases winding; 5, electronic control system; 6, rotating magnetic field; 7, Stator 3 phases winding).*

**Figure 9** shows the design of the double fed alternator.

This type of alternator can transform the nonstandard energy into standard energy without complex units and without additional stages of energy conversion. This is a new approach to solving the problems of wind energy. This Chapter will be devoted to the description of this promising wind turbine.
