WO2011116777A1

WO2011116777A1 - Electrical machine with permanent magnets

Info

Publication number: WO2011116777A1
Application number: PCT/EA2011/000004
Authority: WO
Inventors: Алексей Сергеевич АДАЛЕВ; Сергей Алексеевич БУЛГАКОВ; Алексей Сергеевич КИБАРДИН; Владимир Георгиевич КУЧИНСКИЙ; Владимир Федорович СОЙКИН; Андрей Михайлович ЧИЖОВ
Original assignee: Открытое Акционерное Общество "Научно-Производственное Объединение "Русский Электропривод"
Priority date: 2010-03-25
Filing date: 2011-03-18
Publication date: 2011-09-29
Also published as: EA014727B1; EA201000637A1

Abstract

An electrical machine is proposed which comprises a salient pole stator with coils, and a salient pole rotor made up of a heavy-duty ring and a magnet system that consists of stacks of segmented plates and pole plates and tangentially magnetized permanent magnets. The stacks of pole plates are braced, via clamping plates, in the axial direction by means of a fastening element which is passed through an internal opening in the pole plates and clamping plates, while the stacks of segmented plates are assembled on dovetail-shaped strips which are fixed to the heavy-duty ring with the aid of fastening elements. The proposed electrical machine is characterized in that each stack of segmented plates, together with permanent magnets which directly adjoin said stack on two sides, is surrounded by a heavy-duty tape of electrically insulating material so as to form a segmented unit, wherein there is no electrically insulating tape in the region of the fastening elements which fasten the strip to the heavy-duty ring. In the present invention, a profiled strip of nonmagnetic material is mounted between those ends of the permanent magnets which face the air gap, and each stack of pole plates is arranged between two neighboring segmented units, directly adjoins the lateral edges of said segmented units and is fixed to the heavy-duty ring by means of fastening elements fastened to the clamping end plates of said stack.

Description

PERMANENT MAGNET ELECTRIC MACHINE

FIELD OF THE INVENTION

The present invention relates to electrical engineering, namely to multiphase electric machines with excitation from permanent magnets.

State of the art

The prior art electric generator (EP1 508955 A1, N02K 21/16, 02/23/2005), which contains a stator with a magnetic circuit and a multiphase winding; and a rotor comprising a continuous magnetically conducting cylinder with inclined slots in which permanent magnets are mounted. The rotor poles located between the permanent magnets are turned towards the air gap and are mechanically connected to each other in the direction of the circumference of the rotor by bridges of the material of the cylinder. These jumpers perceive centrifugal forces acting on the poles and permanent magnets.

This design has several disadvantages. The presence of a magnetically conducting jumper causes the presence of magnetic fluxes of dispersion, closing through the jumpers and not passing through the air gap of the machine, which reduces the magnitude of the main magnetic flux passing through the air gap of the machine. To reduce these flows, it is necessary to reduce the cross-section of the jumper, which weakens the mechanical fastening of the poles and permanent magnets and limits the possible speed of rotation of the rotor and, thus, the achieved power of the generator. The presence of scattering fluxes reduces the efficiency of the machine, determines the need to compensate for the loss of magnetic flux by increasing the length of the rotor or the diameter of the rotor, which in turn leads to an increase in the mass of the machine and its cost.

The disadvantage of this design is also significant heat loss from eddy currents associated with the tooth harmonics of the field. These currents are induced in the near-surface conductive layer of the rotor magnetic system, by the formation of poles with jumpers, which negatively affects, especially, at higher rotational speeds. This disadvantage also leads to a decrease in the efficiency of the generator.

Also known is a multi-phase electric machine with permanent magnets (EP 010775 B1, H02K 21/12, 2008.10.30), which contains an explicit pole rotor formed by a power ring and a magnetic system including packages sector plates with recesses in which packages of pole plates are arranged in the shape of a triangle, one of the vertices of which faces the power ring, and tangentially magnetized magnetic blocks located between the packages of sector and pole plates. Each package of pole plates is axially tightened by means of a fastener passed through an internal hole in the pole plates. Each pole plate has a slot for connecting through it the fastening element of the pole plate with the profile element.

Fixing of independent structural units and packages of sector plates on the power ring is carried out by means of wedges installed between independent structural units. Each wedge is connected by pins with a power ring. The studs are fastened with an axial bar rigidly mounted on the power ring.

This design also has several disadvantages. The presence of a mounting element of the pole plate connected to the profile element, and studs connecting the wedges with the power ring, determine the need for the formation of air gaps between the corners of the magnetic blocks, which leads to the appearance of spurious magnetic fluxes that are closed between the ends of the permanent magnets and do not pass through the air gap , this accordingly leads to a decrease in the efficiency of the machine. In the case of ensuring the required machine parameters (power) due to reduced efficiency, this leads to an increase in either the length of the magnetic circuit of the rotor and stator, or the diameter of the bore of the rotor and stator, which ultimately leads to an increase in the mass of the machine and its cost.

SUMMARY OF THE INVENTION

The electric machine of the present invention is devoid of the above disadvantages and at the same time solves the additional tasks. The proposed design provides reliable and safe operation for relatively low-speed machines. ^' Additionally, an increase in the manufacturability of the assembly of the proposed electric machine is implemented, the configuration and the number of elements of the nodes of the rotor magnetic system and, accordingly, the manufacturing cost and the cost of the machine as a whole are simplified.

The proposed electric machine contains an explicit pole stator with coils, an explicit pole rotor formed by a power ring and a magnetic system consisting of packages of sector and pole plates and tangentially magnetized permanent magnets. The packages of pole plates are axially tightened through the pressure plates, by means of a fastener passed through the internal hole in the pole and pressure plates, and the packages of sector plates are assembled on swallow-tail planks and fastened to the power ring using fasteners. An electric machine is characterized in that each package of sector plates, together with permanent magnets closely adjacent to it on both sides, is covered by a power brace made of insulating material, forming a sector block, and in the area of the strap fasteners to the power ring, there is no insulating brace. In the present invention, a profile strip of non-magnetic material is installed between the ends of the permanent magnets facing the air gap, and each package of pole plates is located between two adjacent sector blocks, is tightly adjacent to the side faces of the sector blocks, and is fastened to the power ring by fasteners fastened to end pressure plates of this package. The shape of the surface of the force ring at the junctions of the packages of sector plates with the force ring preferably has the form of a flat surface. Permanent magnets in the preferred embodiment are made in the form of magnetic blocks consisting of several permanent magnets.

Due to the presence of an insulating bandage, blocks with permanent magnets are held under the action of centrifugal forces and the geometric shape of the elements of the magnetic system of the rotor is simplified, the design of the magnetic system of the rotor is simplified, which in turn leads to increased reliability of the structure and lower cost of the machine.

List of drawings

In FIG. 1 is a schematic longitudinal sectional view of an exemplary embodiment of an electric machine of the present invention.

In FIG. 2 is a schematic cross-sectional view of an exemplary embodiment of an electric machine of the present invention.

In FIG. 3 is a schematic cross-sectional view of a rotor portion of an exemplary embodiment of the electric machine of FIG. 2.

In FIG. 4 is a schematic longitudinal section of a portion of the rotor of FIG. one. Information confirming the possibility of carrying out the invention

The following describes one of the possible embodiments of the electric machine of the present invention. Depicted in FIG. 1 and 2, the electric machine has a housing 1, on the ends of which end shields are installed 2. In the housing 1, a stator 3 is installed, consisting of a magnetic circuit 4, having distinct poles and coils 5, laid in grooves of the magnetic circuit 4 and forming a multiphase winding.

Inside the bore of the stator 3, a rotor 6 is installed, consisting of a shaft in the form of two shanks 7, a magnetic system 8 and bearing bearings 9 installed in the end shields 2. The magnetic system 8 of the rotor 6 is mounted on a power ring 10, which is mounted on the shanks 7.

In FIG. 3, 4, a part of the magnetic system is shown on a larger scale. The magnetic system 8 of the rotor 6 consists of packages of sector plates 1 1, packages of pole plates 12 made of laden iron, and tangentially magnetized magnetic blocks 13. At the same time, instead of the magnetic blocks 13 used in the present case as permanent magnets, there can be ^"employed monolithic elements made of magnetic material. Packages pole plates 12 are tightened in the axial direction via the push plate 14 fastening element 15, such as pins, passed through the inner up responses The term package pole plates 12 and the pressing plates 14. Packages sector plates assembled on rails 16 having a shape such as a dovetail, which are fixed to the power ring 10 by fasteners 17.

Each package of sector plates 1 1 together with magnetic blocks 13 tightly adjoining on both sides of it, is covered by a power bandage 18 made of insulating material, forming a sector block 19. In the area of fasteners 17 of the bar 16 to the power ring 10, there is no power bandage 18. Between the ends of the magnetic blocks 13 facing the air gap, a profile strip 20 made of non-magnetic material is installed, and each package of pole plates 12 is located between two adjacent sector blocks 19 and fit snugly to the side faces of the sector blocks 19. The packages of pole plates 12 are mounted on the power ring 10 using fasteners 21 connecting the pressure plates 14 to the power ring 10.

The surface shape of the force ring 10 at the interface between the packages of sector plates 1 1 and the force ring 10 has the form of a flat surface 22. In the present invention, the fastening elements 15, 17 of the nodes of the rotor magnetic system 8, which receive the centrifugal forces acting on the nodes of the magnetic system 8, are placed so that the magnetic blocks at the corners are as close as possible to each other. This ensures the maximum reduction in the magnitude of magnetic fluxes of scattering, shunting the main magnetic flux, and thereby increases the main magnetic flux in the air gap created in the air working gap, which accordingly increases the efficiency of the machine, allows for smaller machine sizes and, accordingly, to reduce the cost of the product. To keep the magnetic blocks 13 from the action of centrifugal forces, to ensure the maximum possible elimination of the air gap between the corners of the magnetic blocks 13, a package of sector plates 1, magnetic blocks 13, strap 6 are covered by a power brace 17. In order for the power brace 18 to be in tension, which ensures strong mechanical fastening of these elements, it is structurally advisable in the area of the ends of the magnetic blocks 13 facing both toward the air gap and towards the power ring 10 to install the strap 16 appropriate form. The power bandage 18 is made of highly durable material, for example, from an electrically insulating tape LSS-F. The use of a power bandage 18 made of an electrical insulating tape makes it possible to eliminate the induced Foucault currents in it when an alternating magnetic flux passes through the magnetic system of the rotor and the corresponding heat losses in the case of these currents flowing through the power bandage 18, which leads to the absence of a decrease in machine efficiency. Since the package of sector plates is fixed to the power ring using fasteners, the magnetic blocks fixed with the help of a power bandage on the packages of sector plates are also held by these elements in their position under the action of centrifugal forces.

The packages of pole plates 12 are glued together and are pulled together in the axial direction to form a single mechanical block, behaving as a monolithic element. This makes it possible to limit the fastening of the package of pole plates through the pressure plates 14 (along the edges of the package) to the power ring 10. This fastening makes it possible to bring the magnetic blocks 13 together as close as possible, eliminate the magnetic fluxes of scattering shunting the main magnetic flux, increase the efficiency of the machine, and simplify the geometric shape package of pole plates 12, to simplify the design of the magnetic system of the rotor, reduce the complexity of manufacturing and, accordingly, the cost of the machine. Thus, centrifugal loads are retained acting on the elements of the rotor magnetic system 8 by securing them on the power ring 10.

To reduce the amplitude of the vibration of the machine, it is widely practiced to carry out the magnetic circuits of the rotor with an oblique groove (A.I. Voldek "Electric Machines", L., Energy, 1978). In this case, the grooves of the magnetic circuit, the groove part of the winding and other elements must have a helical shape . In the embodiment of the machine with permanent magnets, the manufacture of elements of the magnetic system (permanent magnets, poles, strips, etc.) becomes extremely laborious, requires special complex technological equipment, which significantly increases the complexity of manufacturing and, accordingly, the cost of the machine as a whole. Therefore, the simplest way to create oblique grooves for machines with permanent magnets is to create, for example, by milling, on the surface of the power ring a multifaceted surface in which the faces have the shape of a flat surface. This allows you to perform the elements of the magnetic system of the rotor in the form of rectilinear elements and to form an oblique direction to install them on the power ring of the rotor at an angle to the longitudinal axis of the machine. The manufacture of elements of the magnetic system of the rotor of a rectilinear shape significantly reduces the complexity of their manufacture in comparison with their execution in a helical form.

The operation of the electric machine is as follows. The stator coils, which are interconnected as needed, are supplied with AC voltage, and a current begins to pass through them, the amplitude of which varies in time according to the required law. When the flowing current and the magnetic field interact, which is determined by the sum of the fields created by the flowing current and permanent magnets, a rotating electromagnetic moment arises, driving the motor.

Claims

CLAIM

one . An electric machine comprising an explicitly polar stator with coils, an explicitly polar rotor formed by a power ring and a magnetic system consisting of packages of sector and pole plates and tangentially magnetized permanent magnets, wherein the packages of pole plates are pulled axially through the pressure plates by means of a fastener passed through the inner hole in the pole and pressure plates, and packages of sector plates are assembled on dovetail-shaped planks and fixed to force ohm ring, with the help of fasteners, characterized in that each package of sector plates together with permanent magnets closely adjacent to it on both sides is covered by a power bandage of electrical insulation material, forming a sector block, and this bandage in the area of the strap fasteners to the power ring absent, and between the ends of the permanent magnets facing the air gap, a profile strip of non-magnetic material is installed, and each package of pole plates is located between two adjacent sects blocks, tightly adjacent to their lateral faces, and fixed to the power ring with fasteners, which are included in the end pressure plates of this package.

2. The electric machine according to claim 1, characterized in that the surface of the power ring at the interface between the packages of sector plates with the power ring has the form of a flat surface.

3. The electric machine according to claim 1, characterized in that the permanent magnets are magnetic blocks.