RU2807034C1 - Combined excitation electric machine - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: combined excitation electric machine contains an internal armature consisting of two laminated packages made of electrical steel with grooves inserted into a massive magnetic circuit with an annular space made of magnetically conductive material, an armature winding made of copper wire located in the grooves of the laminated packages, an excitation winding made of copper wire located in annular space of a massive magnetic circuit. The outer rotor is made with shortened magnetically conducting poles and with shortened permanent magnets forming two rings, in each of which shortened permanent magnets are inserted into the space between the shortened magnetically conducting poles. The massive magnetic circuit consists of a fixed and moving part, and the movable part of the massive magnetic circuit is attached by means of a threaded connection to the stationary part of the massive magnetic circuit.

EFFECT: improved maintainability and simplified armature assembly technology.

2 cl, 4 dwg

Description

The invention relates to the field of electrical engineering and can be used in electric drives in which it is necessary to change torques and rotation speeds over a wide range, for example, in electric transmissions of vehicles, in generators of autonomous power supplies, in wind power plants.

The main advantage of combined excitation machines is that they have two sources to create the magnetic excitation field. These are permanent magnets and an excitation winding, while the use of permanent magnets makes it possible to reduce the dimensions of the inductor, and the excitation winding allows you to change the resulting magnetic flux, providing wide control of torque and rotation speed.

To ensure increased reliability, the excitation winding must be located on a stationary part and have a non-contact (brushless) current supply.

A known electric machine of combined excitation (combined excitation generator [1]), which contains an armature with two laminated packages with a multiphase armature winding pressed into a massive magnetic circuit, a stationary excitation winding located between the laminated packages of the armature, and a rotor with shortened poles. The poles are made in the form of permanent magnets magnetized radially and shortened in the axial direction, and the shortening for poles of different polarities is made on opposite sides. An insert made of soft magnetic material is installed in place of the shortening. The armature winding consists of coils, each of which is put on two laminated packages located opposite each other. The design described according to the invention has a normal design when the armature is located outside and the rotor is located inside. The normal design, compared to the inverted design, has a smaller diameter of the armature bore due to the back of the armature and the toothed zone of the armature, which reduces the electromagnetic torque and worsens the specific energy parameters. In addition, if the excitation winding fails, it is impossible to replace it without dismantling the armature winding and removing one of the laminated packages. This makes the structure unrepairable. This design complicates the armature assembly technology.

The closest technical solution is a combined excitation electric machine [2], which contains an internal armature consisting of two packages laminated from electrical steel with grooves, inserted into a massive magnetic circuit with an annular space made of magnetically conductive material, an armature winding made of copper wire located in the grooves laminated packages, field windings made of copper wire located in the annular space of a massive magnetic core, an external rotor with shortened magnetically conducting poles without a bevel and with shortened permanent magnets without a bevel, inserted into the space between the poles from two opposite sides around the circumference, with permanent magnets in the axial direction are located opposite the magnetically conducting poles and have radial magnetization of one polarity on one side and the opposite polarity on the other side. The electric machine described according to the invention [2] has an inverted design, in which the armature is internal and the rotor is external, which allows, in the same dimensions, compared to a normal design, to increase the diameter of the armature bore, thereby increasing the electromagnetic torque and improving the specific energy performance. At the same time, the design of the armature, just like the analogue described above, does not allow replacing the excitation winding in the event of its failure, without dismantling the armature winding and removing the laminated package and the massive magnetic circuit. This also makes the design low-tech and unrepairable.

The technical task and technical result of the proposed invention is to improve maintainability, increase the manufacturability of the assembly, due to the implementation of a massive magnetic circuit of two parts: fixed and moving, as well as reducing the reactive torque of the electric machine due to the fact that the shortened magnetic poles and shortened permanent magnets are made with a bevel per one tooth division of the armature.

The technical task is achieved due to the fact that in a combined excitation electric machine containing an internal armature consisting of two laminated packages of electrical steel with grooves inserted into a massive magnetic circuit with an annular space made of magnetically conductive material, armature winding made of copper wire, located in the grooves of laminated packages, field winding made of copper wire, located in the annular space of a massive magnetic circuit, external rotor with shortened magnetically conducting poles without bevel and with shortened permanent magnets without bevel, inserted into the space between the magnetically conducting poles from two opposite sides along the circumference, while the permanent magnets in the axial direction are located opposite the magnetically conducting poles and have a radial magnetization of one polarity on one side and the opposite polarity on the other side. The massive magnetic circuit is made of two parts: fixed and movable. The moving part of the massive magnetic circuit is attached by means of a threaded connection to the stationary part of the massive magnetic circuit. In the proposed design, the moving part can be removed from the armature without dismantling the armature winding when removing the threaded connection. Following this moving part, the field winding can be removed from the armature for repair or replacement. In addition, in this design, to reduce the reactive torque, the shortened magnetic poles and shortened permanent magnets are made with a bevel of one tooth division of the armature bc, equal to , WhereD - anchor diameter, m; z is the number of armature teeth.

The novelty of the technical solution is due to the fact that by making the design of the massive magnetic circuit dismountable in two parts, movable and fixed, it becomes possible to remove and replace the field winding without dismantling the armature winding and the armature itself, which makes the design technologically advanced and maintainable. In addition, a new distinctive feature is, if it is necessary to reduce the reactive torque, the implementation of shortened magnetically conducting poles and shortened permanent magnets of the rotor with a bevel by one tooth division of the armature.

The essence of the invention is illustrated by illustrations in Fig. 1, 2, 3, 4, which shows the following: FIG. Figure 1 shows the design of an electrical machine in cross-section in two views; in fig. 2 shows the procedure for removing the field winding from the armature; in fig. 3 shows the bevel of shortened poles and shortened permanent magnets by one tooth division of the armature; in fig. Figure 4 shows a fragment of laboratory tests of a combined excitation switched-type electric motor as part of a motor-wheel for an electric racing car, as an example of the application of the proposed combined excitation machine.

The operating principle of a combined excitation machine is based on obtaining the resulting flux from permanent magnets and the excitation winding.

Combined excitation electric machine (Fig. 1, 2, 3) has an inverted design, in which there is an internal armature and an external rotor 5. The armature consists of two laminated packages of electrical steel 1.2 with grooves, inserted into a massive magnetic circuit with an annular space made of magnetically conducting material, an armature winding 3 of copper wire located in the grooves laminated packages 1, 2, excitation winding 4 made of copper wire, located in the annular space of a massive magnetic circuit. The outer rotor 5 has shortened magnetically conductive poles without a bevel 6 and shortened permanent magnets without a bevel 7. Shortened permanent magnets 7 are inserted into the space between the shortened magnetically conductive poles 6 from two opposite sides around the circumference, while the shortened permanent magnets 7 in the axial direction are located opposite the shortened magnetically conductive ones There are 6 poles and have a radial magnetization of one polarity on one side and the opposite polarity on the other side. The massive magnetic core consists of two parts: a fixed part 8 and a moving part 9. The moving part of the massive magnetic core 9 is attached using a threaded connection 10 to the fixed part of the massive magnetic core 8.

In this design (Fig. 1, 2, 3), if necessary, to reduce the reactive torque, shortened magnetic conductive poles 6 and shortened permanent magnets 7 are made with a bevel of one tooth division of the armature.

The bevel angle in one tooth division of the armature is determined by the formula [3, p. 386]:

Where - bevel angle, rad

- bevel value equal to the tooth division of the anchor, m

- pole division, m

The pole division can be determined by the formula [3, p.41]

where D is the diameter of the anchor, m

p - number of pole pairs.

The tooth division of the anchor can be determined by the formula [3, p.43]

where z is the number of armature teeth.

It is known that to reduce the reactive torque, a bevel of the armature teeth themselves [3, p. 386, Fig. 20-2] of the electric machine is used by one tooth division. The poles remain unmapped. In the proposed design of the electric machine, due to the presence of two laminated armature packages 1,2, the bevel of the armature teeth themselves complicates the manufacturing technology of the armature winding 3, since the conductors of the armature winding 3 must be bent. In addition, the armature winding 3 with the bending of the conductors is difficult to place in the grooves of the laminated packages 1,2. In this regard, it is proposed to perform a bevel by an amount equal to one tooth division of the armature bc, determined by equation (1), for shortened magnetically conductive poles 6 and shortened permanent magnets 7, and leave the grooves of the laminated packages 1,2 straight without bevel.

The proposed electric machine works as follows. The magnetic flux for excitation is created simultaneously by the excitation winding 4 and permanent magnets 7. The magnetic flux from the shortened permanent magnets 7 is closed along the following path: the shortened permanent magnet 7 of southern magnetization, the air gap, the toothed zone of the laminated package 1, in the grooves of which the armature winding 3 is located, the fixed part of the massive magnetic circuit 8, the moving part of the massive magnetic circuit 9, the toothed zone of the laminated package 2, in the grooves of which the armature winding 3 is located, the air gap, the shortened permanent magnet 7 of northern magnetization, the magnetic circuit of the outer rotor 5.

The magnetic flux from the excitation winding 4 closes along the following trajectory: a shortened magnetic conductive pole 6, an air gap, the toothed zone of the laminated package 1, in the grooves of which the armature winding 3 is located, the stationary part of the massive magnetic circuit 8, the moving part of the massive magnetic circuit 9, the toothed zone of the laminated package 2 , in the grooves of which there is an armature winding 3, an air gap, a magnetically conductive shortened pole 6, a magnetic circuit of the outer rotor 5.

Thus, in the armature winding 3, located in the grooves of laminated packages 1 and 2, the total EMF is the sum of the EMF, which is induced by the flux from the permanent magnets 7 and the EMF, which is induced by the flux from the excitation winding 4. The EMF from the permanent magnets 7 does not change, but The EMF from the excitation winding 4 can vary, which makes it possible to regulate the electromagnetic torque and rotation speed over a wide range along the low-current excitation circuit.

If the excitation winding 4 fails, it can be removed by removing the threaded connections 10, the moving part of the massive magnetic circuit 9 is pulled out in the axial direction and then removed from the armature without dismantling the armature winding 3 for repair or replacement (Fig. 2). The field winding 4 is removed from the armature as follows. The threaded connection 10 is removed. During this operation, the moving part of the massive magnetic core 9 is loosened. The moving part of the massive magnetic core 9 is removed from the armature in the axial direction. Next, the field winding 4 is removed from the armature in the axial direction. The field winding is assembled in the reverse order.

The advantage of the proposed design lies in the ease of installation and dismantling of the excitation winding 4, which improves the manufacturability of the design and increases its maintainability.

In addition, the bevel of the shortened magnetically conducting poles 6 and the shortened permanent magnets 7 per one tooth division of the armature is equal to , where D is the diameter of the armature and z is the number of armature teeth, reduces the reactive torque. It was experimentally established that for the combined excitation electric machine used for the motor-wheel of an electric car (Fig. 4), the bevel of the shortened magnetically conducting poles 6 and shortened permanent magnets 7 by one tooth division of the armature bc reduced the reactive torque by 80% compared to the option without bevel of shortened magnetically conducting poles 6 and shortened permanent magnets 7.

The proposed technical solution is industrially applicable. A combined excitation valve motor of the described design was used as part of a motor-wheel for an electric racing car, tested in laboratory conditions. A fragment of the tests is shown in Fig. 4.

Information sources

1. RF Patent 2439770, Voronin S.G., Sogrin A.I., Murdasov B.A., Kislitsin V.I. Patent holder South Ural State University (RU), - publ. 10/07/2010

2. RF Patent 2244996, Ganja S.A., Solomin E.V., Schaufler A.D. Applicant ZAO Scientific Research Institute "URALMET" (RU), - publ. 07/31/2003

3. Voldek A.I. Electric cars. Textbook for students of higher technical educational institutions. - 3rd ed., revised. - L.: Eneriya, 1978. - 832 p. ill.

Claims (2)

1. An electric machine of combined excitation, containing an internal armature consisting of two laminated packages made of electrical steel with grooves inserted into a massive magnetic circuit with an annular space made of magnetically conductive material, an armature winding made of copper wire located in the grooves of the laminated packages, an excitation winding made of copper wire , located in the annular space of a massive magnetic circuit, an external rotor with shortened magnetically conducting poles and with shortened permanent magnets forming two rings, in each of which shortened permanent magnets are inserted into the space between the shortened magnetically conducting poles, while the shortened permanent magnets in the axial direction are located opposite the shortened ones magnetically conducting poles and have radial magnetization, characterized in that the massive magnetic circuit consists of a fixed and moving part, and the movable part of the massive magnetic circuit is attached by means of a threaded connection to the fixed part of the massive magnetic circuit. 2. An electric machine according to claim 1, characterized in that the shortened magnetically conducting poles and shortened permanent magnets are made with a bevel by one tooth division of the armature bc, equal to ,WhereD- anchor diameter, m; z – number of armature teeth.