RU2774117C1 - Inductor wind generator with integrated magnetic gear - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering, namely to electric machines used as generators in wind turbines.

EFFECT: stabilizing the voltage and frequency at the output terminals of the generator at a variable speed of rotation of the wind wheel and simplifying the design, achieved due to the fact that the modulator of the magnetic gear built into the inductor wind generator is a low-speed rotor rigidly attached to the shaft of the wind wheel, and between the stator packages, there is a coil with an adjustable DC current.

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Description

The present invention relates to the field of electrical engineering, namely to electrical machines used as generators in wind turbines.

Closest to the claimed design are two.

The first is discussed in an article titled "Improved Motor Intergrated Permanent Magnet Gear for Traction Applications") [1], which considers an electric machine with an integrated magnetic gear, having a fixed stator of a frequency-controlled synchronous motor. This motor drives the high-speed shaft of the built-in magnetic gearbox.

The differences between this design and the proposed one are that, firstly, having similar structural elements, it is a low-speed adjustable high-torque motor, and not a voltage-controlled generator, and secondly, the magnetic field in it is created by high-energy permanent magnets. The use of such magnets greatly increases the cost of the design. There are no magnets in our design.

The second design, close to the one under consideration, is protected by patent No. 2526540 (Russian Federation) [2]. It presents an inductor-type magnetic gearbox, also designed for a wind farm, the magnetic field in which is created by a DC coil. The task of this gearbox is to ensure the constancy of the speed of a separate remote (not built into the design of the gearbox) generator at a variable speed of the wind wheel. The differences between this design and the claimed one are that, firstly, it has only one stator core with a three-phase winding, and secondly, it does not have a synchronous motor for this reason.

The technical result of the invention is that:

1) an inductor generator with a built-in magnetic reducer in combination with a control system makes it possible to maintain unchanged voltage and frequency levels at its output terminals at a variable speed of the wind wheel;

2) the cost of an electric machine is significantly reduced, since the magnetic field in it is created without the use of expensive high-energy permanent magnets.

The technical result is achieved due to the fact that the modulator of the magnetic gearbox built into the inductive wind generator is a low-speed rotor rigidly attached to the wind wheel shaft, and a coil with an adjustable direct current is located between the stator packs.

The presence of an adjustable synchronous motor in our design ensures the stabilization of the mode of its own built-in generator winding. This difference provides smaller dimensions, cost indicators and compactness of the entire wind turbine. The advantage over known wind turbines is that it allows you to maintain the same levels of voltage and frequency at its clamps at a variable speed of the wind wheel.

In FIG. 1 shows longitudinal (a) and transverse (b) sections of an inductor wind generator with a built-in magnetic gearbox.

The proposed inductor-type electric generator has two separate axially arranged stator cores with three-phase windings on each.

The winding of one stator (left in Fig. 1) has the number of pairs of poles ρ and is connected to an adjustable frequency converter. This stator, together with its toothed rotor with the number of teeth Z ₁ , form an inductor synchronous electric motor that rotates another toothed rotor, having a common shaft with it, with a large number of teeth Z _{2 of} an inductor electric generator with an integrated magnetic gearbox.

The stator winding (right in Fig. 1) of this generator is connected to an external load and has a small number of pole pairs p ₁ .

The magnetic transmission modulator is a low-speed rotor, which contains z=p ₁ + _{z 2} laminated ferromagnetic rods and has an output shaft articulated with the wind wheel.

Between the said stator cores there is a coil with direct current, which is one of the sources of the magnetic field.

The unipolar magnetic flux generated by this coil is closed through the wind turbine housing, stator and rotor cores and a common shaft. The principle of operation of the proposed wind generator.

The proposed design is similar to a two-stator classical inductor generator, in which both 3-phase windings are generator windings [3].

In the considered wind generator, 3-phase windings have a different number of pairs of poles, and one operates in the motor mode, receiving power from an adjustable frequency converter, the other is a source of 3-phase voltage with a given level of amplitude and frequency.

Rotary laminated cores have a different number of teeth and a common shaft in the absence of its output end outside the bearing shield.

The main difference from the classical design is the presence of a magnetic transmission modulator, which is a low-speed rotor articulated with the wind turbine shaft.

Let's designate: Ω ₁ , Ω ₂ - speeds of the modulator and the common shaft of the rotors, respectively, ω - angular frequency of the generator output voltage. Then connection. between them is expressed by the basic equality [4]:

where z is the number of modulator rods, _{z 2} is the number of rotor teeth having a common air gap with the modulator. And:

where p ₁ is the number of pairs of poles of the stator generator winding.

The rotation speed of the common shaft of rotors Ω ₂ is set by a synchronous motor in accordance with the formula:

where ω ₁ , Z ₁ - respectively, the angular frequency of the current of the stator winding of the motor and the number of rotor teeth of this motor.

If we take z=19, _{z 2} =16, then according to formula (2) we get p ₁ =3.

In accordance with formula (1), we will have at a given frequency of the generator stator winding

ω=2πƒ=2π⋅50=314 rad/s

and wind turbine speed

Ω ₁ \u003d 10 rad / s the required speed Ω ₂ of the generator rotor

We take the number of teeth of the motor rotor Z ₁ =6, then the angular frequency of the motor stator current ω ₁ in accordance with formula (3) will be equal to the required speed Ω ₂ :

ω ₁ \u003d Z ₁ ⋅Ω ₂ \u003d 6 168.03 \u003d 1008.2 rad / s.

This value ω ₁ corresponds to the motor stator current frequency:

Thanks to the adjustable motor and the adjustable direct current of the excitation coil, the frequency and voltage of the generator are maintained unchanged with a change in the speed of the wind wheel rigidly articulated with the modulator.

Sources of information

1.T.V. Frandsen, P.O. Rasmussen, K.K. Jensen. "Improved Motor Integrated Permanent Magnet Gear for Traction Applications", ECCE 2012, pp. 3332-3339.

2. Patent for invention No. 2526540 (RF), IPC H02K 16/02. Electromagnetic reducer, dec. 09/05/2013; publ. 08/27/2014. Bull. No. 24. Authors: Afanasiev A.A., Chikhnyaev V.A. Applicant: Chuvash State University. I.N. Ulyanov.

3. Alper N.Ya., Terzyan A.A. inductor generators. M.: Energy, 1970. 192 p.

4. Afanasiev A.A. Analytical and numerical methods for solving problems of electromechanics based on the complex magnetic potential. Cheboksary: Chuvash Publishing House. un-ta, 2017. - 430 p.

Claims (1)

An inductor wind generator with a built-in magnetic gearbox, containing two packages of stator cores with three-phase windings and gear rotors, an adjustable induction motor with a frequency converter having a common shaft, one of the stator packages is a synchronous inductor frequency-controlled motor powered by a frequency converter, the other is synchronous a generator with a built-in magnetic gearbox, characterized in that the magnetic gearbox modulator is a low-speed rotor rigidly attached to the wind wheel shaft, and a coil with an adjustable direct current is located between the stator packs.

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