RU195699U1 - PERMANENT MAGNET GENERATOR - Google Patents

Abstract

The utility model relates to electrical engineering and is an electric machine designed to generate and power a load with direct current. Various constructions of electric machines are known from the prior art, including using permanent magnets to drive EMF in their output windings to power the load with direct current. The use of permanent magnets as a replacement for the pole windings provides an improvement in the mass and dimensions of the electric machine as a whole. The efficiency also increases, the losses on the excitation of the magnetic field are reduced. The only fundamental drawback of the solutions known from the prior art is the excitation of an alternating voltage in the output windings of the generator, and the presence of a mechanical sliding contact in the form of a collector or rings for its conversion into direct current at the output of the generator. This leads to a decrease in the reliability of the design of the generator due to wear of the contact point, and also limits the scope of all such decisions to the maximum permissible load on the switched current. In the case of the use of brushes, sparking occurs at the contact point, as well as contamination with coal dust. The proposed solution describes a permanent magnet generator that has the advantages of excitation without mechanical brushes, while providing DC power to the load. This is achieved by changing the path of the magnetic flux from the permanent magnets to perpendicular to the direction of rotation of the generator rotor. Thus, the magnetic flux of the rotor poles passes in the longitudinal axis of the generator, along its geometric axis of rotation. The achieved technical result of the solution is the possibility of supplying the load with direct current without using any kind of brushes and diode switches in the generator design.

Description

The name of the utility model. Permanent Magnet Generator.

The technical field to which the utility model belongs. The utility model relates to electrical engineering and is an electric machine designed to generate and power a load with high quality direct current.

The prior art. The prior art unipolar current generator [RF patent for the invention No. 2518461] containing a rotating rotor and a fixed stator. As a rotor rotating in a perpendicular magnetic field, a stacked disk of metal plates (disk sectors) separated by dielectric spacers with sliding contacts on the axis of rotation of the disk is used. The poles of a rotating constant or alternating magnetic field are used as a fixed stator, and the number of sectors of the rotor is equal to the number of stator poles or more, and the stator poles of a 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 directions of the EMF created by the diametrically arranged poles in the rotor are aligned, and the adjacent poles (along the perimeter) create alternating directions of the diametrical polarity of the EMF on the rotor.

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

Also known multi-shaft unipolar electric machine [RF patent for the invention No. 2634350], containing the excitation system, conductive disks having a common point of contact, as well as two current collectors. In this case, the axes of the conductive disks are parallel and rotate in different directions, and the excitation system is made up of a series of inductors made in the form of a U-shaped magnetic circuit and containing excitation windings. Inductors are located parallel to the planes of rotation of the disks, and the number of inductors is equal to the number of disks plus one. Each of the inductors covers both halves of two adjacent disks, and the two extreme inductors cover the halves of two extreme disks, the current collector is implemented by a pair of current collectors from the extreme points of the circumferences of the extreme disks.

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

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

Disclosure of a utility model. The prior art various designs of electrical machines [1]. Many of them use permanent magnets to obtain a magnetic flux of excitation, which leads to the appearance of a variable EMF in the generator windings during their mechanical rotation. Solutions are possible that use field windings to produce magnetic flux - most of them require mechanical contact, for example, rings on the rotor with brushes for their operation. Thus, the use of permanent magnets to obtain magnetic flux simplifies the design, and eliminates the contacts for transmitting current to the field winding. In addition, permanent magnets can improve the efficiency of an electric machine, and often significantly reduce weight and dimensions.

The successes of modern industry in the extraction and processing of rare-earth metals, as well as the manufacture of permanent magnets with a high value of coercive force (and magnetic induction) have ensured the serial production of various electric machines with magnetic poles from permanent magnets. Significant capacities are available, up to 1-3 MW, which allowed their use in electric propulsion systems.

And although engines make up a significant part of the manufactured machines with permanent magnets, their application for generating electricity is also relevant. Replacing the winding poles of the excitation rotor of the synchronous generator with permanent magnets allows you to get rid of the contact rings on the rotor and the brush apparatus for transmitting current to the rotor windings, but provides only alternating current at the output.

A distinction is made between alternating and direct current generators, and lately, DC power has been receiving ever greater potential. This is due to the widespread use of electronic power supplies and frequency converters with a DC link in their structure as part of the electric drive and other systems. Thus, any consumer can receive backup power from a direct current network. In addition, there are special processes that require DC power - which makes it important to create reliable high-power DC generators.

One way to increase the reliability of DC generators is to eliminate or minimize the number of current collectors and mechanical brush contacts [1]. The presence in the design of classical DC generators of the collector and the brush apparatus on it leads to wear of the brushes and the need for frequent maintenance, as well as to the release of coal dust into the surrounding air. The use of the collector also leads to a limitation of the maximum power delivered to the load.

The task of creating a non-contact direct current generator that does not have any type of current collection in its design remains open. The reason for this lies in the fact that in the solutions known from the prior art, the EMF variable is induced in the windings of the DC generator, which is rectified by means of a sliding contact or a block of diodes.

Any permanent magnet has a direction of its magnetization, and two poles: north (N) and south (S), the lines of force of which are closed between themselves, forming a closed loop of the magnetic flux.

In the constructions of direct current generators known from the literature, the magnetic field is excited by installing permanent magnets on the rotor of the generator, the magnetic poles always alternating with their polarity - which determines their interaction with each other.

The alternating passage of the magnetic flux of the north and south poles through the windings of direct current generators leads to the induction of a variable EMF in them. This makes inevitable the use of various kinds of switching (mechanical or using diodes) for rectifying the current and supplying the generator load with direct current [1].

The proposed solution has no such drawback, and does not contain any kind of switching equipment and current collectors in its design. Due to this, the reliability of operation is significantly increased, and the time required for maintenance by personnel is reduced. In addition, the problem of obtaining significant powers and high voltages is solved, since there are no power-limiting elements.

The figure 1 shows a cross section of the proposed generator in the installation area of the first set of magnets. It can be seen from the figure that the magnets are mounted around the circumference of the rotor with the same polarity, which radically distinguishes the proposed solution from classical DC electric machines. On the stator are the teeth on which the output winding coils are installed. When the rotor rotates, the excitation flux changes from the permanent magnets mounted on it, but its polarity remains unchanged. Thus, in the coils installed on the teeth, a voltage of the same polarity is always induced, having some beats caused by the tooth structure of the magnetic circuit of the proposed generator.

The figure 2 shows a cross section of the proposed generator in the installation area of the second set of magnets. It can be seen from the figure that the magnets are mounted around the circumference of the rotor with the same polarity inverse to the polarity of the first set of magnets.

When the rotor of the proposed generator rotates, the second set of magnets will induce the coils with a constant voltage, which has a different sign relative to the voltage in the coils of the first set.

Figure 3 shows a longitudinal section of the proposed generator, it can be seen from the figure that the magnetic field lines shown by dashed lines with arrows are closed in the longitudinal axis of the generator.

The excitation flux created by the sets of magnets is closed between the opposite poles of the magnets of different sets, passing through the stator and along the rotor along its axis of rotation. In other words, the magnetic flux of permanent magnets passes not in the transverse plane of the generator, but in its longitudinal axis, parallel to the axis of rotation. In this case, the magnetic field never changes its polarity in the teeth of the stator, and also magnets from one set do not interact with each other.

In FIG. 4, an electrical circuit diagram of connecting the coils of the first and second sets in series and according to, so that the voltages of both sets of coils are added together.

The proposed solution is one of a kind, since the direction of the lines of force of the magnetic field in the stator is perpendicular to the direction of rotation of the rotor.

The presented solution is simple and therefore industrially applicable, providing power to the load with direct current without any kind of mechanical contacts and switches. The basis of its action is the excitation of the EMF of one polarity in the coils of the output winding, since the direction of the magnetic flux through them never changes. Thus, when the rotor rotates, a sequence of identical poles is provided - either N or S. Thanks to this, voltage rectification and the use of a brush apparatus are not required.

Separation of sets of permanent magnets, as well as sets of stator coils by an air gap prevents their interaction directly, bypassing the stator magnetic circuit.

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

- the rotating rotor is equipped with two sets of magnets;

- all magnets from one set are located around the circumference of the rotor in the same polarity;

- sets of magnets are mutually inverse polarity;

- sets of magnets are separated by an air gap;

- the fixed stator is equipped with two sets of coils;

- teeth with coils of different sets mounted on them are separated by an air gap;

- coils in each set are connected in series and in accordance;

- sets of coils are connected in series and in accordance, forming an output winding.

Thus, the entire set of essential features of the utility model is previously unknown and leads to a new technical result - providing DC power to the load without using any kind of mechanical contacts and switches.

A brief description of the drawings. The figure 1 shows a cross section of the proposed generator in the region of the first set of permanent magnets. The figure 2 shows a cross section of the proposed generator in the region of the second set of permanent magnets. The figure 3 shows a longitudinal section of the proposed generator. Here 1 is a stator, 2 is a rotor, 3 is a permanent magnet, 4 is a coil. The figure 4 shows a circuit diagram of the output winding.

List of used literature.

1. Kopylov I.P. Design of electrical machines. M .: Yurayt, 2014.767 s.

Claims (1)

A permanent magnet generator comprising a fixed stator with an output winding, a rotor with permanent magnets, characterized in that the rotor is equipped with two sets of magnets, the magnets of one set being circumferentially aligned in the same polarity, the sets of magnets are mutually inverse polarity and separated by an air gap, fixed the stator is equipped with two sets of coils mounted on its teeth, and the teeth of different sets of coils are separated by an air gap, the coils in each set are connected in series and in accordance, sets of coils are connected in series and in accordance, forming an output winding.

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