RU211722U1 - SINGLE-PHASE CONTACTLESS UNIPOLAR GENERATOR - Google Patents

Abstract

The utility model relates to electrical machines and can be used in electrical generators, including wind turbines and generators of autonomous objects. Various types of synchronous generators are known from the prior art, which have common features - this is the presence of excitation poles, as well as the separation of the source of the excitation field (permanent magnet or winding) into the stator and rotor, while in classical electric machines the excitation winding is made in the form of coils located on the teeth of the rotor. The current to the excitation winding in this case is supplied through the brushes to the rings on the rotor and then to the excitation winding. The disadvantage is the need for periodic maintenance, replacement of brushes, reversal of the polarity of the rings, as well as their grinding and beating control. Variants of generators with excitation from permanent magnets do not have brushes, but do not allow you to adjust the excitation flux and the level of its output voltage, which limits the scope. This disadvantage is especially significant when the load is powered directly from the generator, which is sensitive to the voltage level. Variants of a generator with longitudinal excitation are also known, in which the excitation flow is closed longitudinally to the axis of rotation of the rotor. However, their non-magnetic (possibly plastic) casing design is better suited for small to medium power generators. Also known are synchronous generators without brushes and with the ability to control the level of excitation through the use of three machines on one shaft. This is a composite machine consisting of three generators, one of which is executed inverted. In the proposed solution, both windings - both excitation and output, are located on the stator. The excitation winding is installed on the poles and creates a magnetization flux, which is switched by the rotor teeth to the stator teeth with the output winding coils. Two pairs of coils form an output winding when connected in series.

Description

Field of technology to which the utility model belongs

The utility model relates to electrical machines and can be used in electrical generators, including wind turbines and generators of autonomous objects.

State of the art

The prior art unipolar current generator [RF patent for invention No. 2518461], containing a rotating rotor and a fixed stator. As a rotor rotating in a perpendicular magnetic field, a type-setting disk made of metal plates (disk sectors) separated by dielectric spacers with sliding contacts on the disk rotation axis is used. As a fixed stator, the poles of a rotating constant or alternating magnetic field are used, and the number of sectors of the rotor is equal to the number of stator poles or more, and the stator poles of the rotating magnetic field can be created by rotating magnets, or electromagnets, or fixed windings with a magnetic circuit inside, in which a rotating constant or variable field. The number of rotating poles can be 2 or more, subject to the condition that the EMF directions created in the rotor by diametrically located poles are co-directed, and neighboring poles (along the perimeter) create alternating directions of EMF diametrical polarity on the rotor.

The disadvantages of this solution include the presence of a sliding contact apparatus (current collectors), which reduces reliability.

A brushless generator is also known [RF patent for utility model No. 195231], containing a fixed stator with an output winding consisting of coils, a rotor equipped with a cylindrical permanent magnet, sets of poles made of ferromagnetic material installed from its ends and having a through hole in its center each , with dielectric spacers from the inside to isolate the plates of the set of poles from the shaft rotor, the rotor is made composite with a shaft of non-magnetic material in the center, and the stator is made of non-magnetic material and is equipped with slots for magnetic cores, each magnetic core is installed in its corresponding slot longitudinally to the direction of the rotor rotation axis and has two teeth protruding into the cavity of the stator, respectively, sets of poles. The number of poles in the set is one more than half of the number of stator magnetic circuits, with the number of stator magnetic circuits being a multiple of two.

This decision is made by the main prototype, the closest in its technical essence.

The disadvantages of this solution include the presence of a toothed zone of the stator magnetic circuits, which complicates their design, and also makes it impossible to smooth the magnetic flux by manufacturing teeth with extensions.

Utility Model Disclosure

Various designs of electrical machines are known from the prior art [1, 2]. Many of them use permanent magnets to produce a magnetic excitation flux, which leads to the appearance of a variable EMF in the generator windings when they are mechanically rotated. Solutions are also possible using excitation windings to obtain a magnetic flux - most of them require mechanical contact for their operation, for example, rings on a rotor with brushes. Thus, the use of permanent magnets to obtain a magnetic flux simplifies the design and makes it possible to exclude contacts for transmitting current to the field winding, but does not allow changing the magnetic flux of excitation. In classical synchronous generators, the excitation winding and the output winding are always located separately on the stator and rotor.

Since the presence of mechanical contact between brushes and rings can significantly complicate operation (the need for replacement, the likelihood of a sudden failure with the destruction of the brushes), the search for a solution with the simplest, most convenient and efficient design is underway.

At the moment there are only two versions of such a generator without brushes, known from the prior art. The first is the use of a composite electric machine consisting of two or three generators on a common shaft, one of which is reversed (the stator-rotor windings are reversed). Such generators are used in aviation and often in shipbuilding, where they are installed in emergency power sources. The second is the design of the generator with a longitudinal magnetic flux, proposed earlier by the author of this application. Both of these options have both advantages and disadvantages.

In the proposed solution, there are no brushes and rings on the rotor, with a simple design and the use of a classic generator, without the use of a longitudinal magnetic flux. This is achieved by transferring the excitation poles from the rotor to the stator, and placing them separately from the teeth with the coils of the output winding, i.e. unlike the classical generator, separate coils on the teeth are used.

Figure 1 shows the appearance of the 3D model of the proposed solution, which shows the presence of two (larger) pole coils located opposite each other (diametrically), as well as four coils of the output winding located on the stator teeth. The figure also shows that the rotor is made without coils and contains six teeth. In FIG. 2 shows a cross-section of a 3D model of the proposed solution, which also clearly shows the location of the coils on the teeth and poles of the stator.

Figure 3 shows the device of the proposed solution, which indicates its components - made of ferromagnetic stator (1), rotor (6), as well as pole coils (2) and output winding coils (4) mounted on poles (3) and teeth (5) stator.

Also in FIG. 3, the arrows show the direction of the excitation magnetic flux, which is the same for both poles - thus, this generator is inherently unipolar. The magnetic flux of the poles is the same, and the direction of the magnetic field passing through the coils of the output winding does not change its sign.

In FIG. 4 shows the distribution of magnetic field lines during the operation of the proposed solution, where you can see the direction of their distribution by the rotor teeth to the stator teeth with output winding coils on them. In FIG. 5 shows the graph of the output voltage of the proposed solution, obtained on a 3D model in the ANSIS software environment. The voltage has a fairly high degree of sinusoidality, which can be improved by optimizing the geometry and shape of the rotor teeth.

The principle of operation of the proposed solution is based on switching the magnetic field created by the excitation poles on the stator to the teeth with the coils of the output winding. The combination on a common stator of two types of magnetic circuit - excitation poles and coils of the output winding has not been used previously in electrical engineering.

All the features indicated in the distinctive part of the formula are essential for the implementation of the proposed solution, and are not previously known from the prior art in their entirety. The use of four teeth combined into 2 pairs of teeth allows to increase efficiency, since in combination with the number of teeth of the rotor, it allows the generation of EMF in all four coils of two pairs. Thus, the generation process takes place simultaneously in a larger number of turns, while the magnetic field from the individual teeth of the rotor does not overlap.

The presented solution is simple and therefore industrially applicable, providing ease of manufacture of components and the assembly process of the generator. An exception to the design of the complex shape of magnetic circuits has been achieved and toothed coils are used, which are manufactured separately from the generator itself and installed during its assembly.

The proposed technical solution is new and has the following fundamental differences from the main prototype:

two excitation poles have coils on each with the same polarity of the magnetic field they create;

four coils of the output winding are placed on four stator teeth, combined in pairs, these pairs of stator teeth are located diametrically and opposite to each other between the excitation poles;

the output winding coils are connected in series and according to;

the rotor has six teeth.

Thus, the whole set of essential features of the utility model is previously unknown and leads to a new technical result - the absence of brushes, and thus to simplify the design.

Brief description of the drawings

In FIG. 1 shows the appearance of the proposed solution. In FIG. 2 shows a cross section of the proposed solution. In FIG. 3 shows the device of the proposed solution. Here 1 is the stator, 2 is the pole coil, 3 is the pole, 4 is the output winding coil, 5 is the tooth, 6 is the rotor. In FIG. 4 shows the magnetic field lines of the proposed solution. In FIG. 5 shows a plot of the output voltage of the proposed solution.

List of used literature

1. Kopylov I.P. Design of electrical machines. M.: Yurayt Publishing House, 2014.

2. Shtelting G., Beisse A. Electric machines. M.: Publishing house "Energoatomizdat", 2015.

Claims (1)

A unipolar generator containing a fixed stator with excitation poles on it and a rotor made of ferromagnetic material, and characterized in that two excitation poles are equipped with coils that have the same polarity of the magnetic field they create, four coils of the output winding are placed on four stator teeth, combined in pairs, pairs of stator teeth are diametrically and opposite to each other between the excitation poles, with the output winding coils connected in series and in accordance, and the rotor has six teeth.

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