RU2704491C1 - Synchronous electric motor with magnetic reduction - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering, namely to synchronous motors with excitation from permanent magnets. Synchronous motor with magnetic reduction includes housing 1 and bearing shields 2, 3. Rings 4, 5 of stator magnetic conductor are installed on them. On rings 4, 5 there are twelve teeth 6, 7 with crowns and coils 8, 9. Four permanent magnets 10 are installed on bushing 11 of rotor of fast rotation. Stator discs 14, 15 are secured on stator sleeves 12, 13. Slow rotation rotor disks 18, 19 are fitted on bushings 16, 17. Stator discs 14, 15 and slow rotation rotor disks 18, 19 have ferromagnetic and non-magnetic elements in the form of sectors. On end surfaces of teeth 6, 7 there are protrusions, angular position of which coincides with position of ferromagnetic elements of stator discs. Shaft 20 rests on bearings 21, 22. They are installed in bearing shields 2, 3. Rotor of fast rotation rests on bearing 23 installed in the middle on shaft 20. Amount of ferromagnetic elements on stator disc z_c and on rotor disk z_p are related by equality z_p=z_c±2p, where p is number of pole pairs of stator winding. With number of stator teeth z=6p and making coils around two adjacent teeth creating spatial harmonics of MMF along gap without even harmonics, synchronous motor with improved energy indices is obtained.

EFFECT: improvement of power characteristics of synchronous electric motor.

1 cl, 7 dwg

Description

The invention relates to electric machines, and in particular to synchronous motors with excitation from permanent magnets, and can be used as a compact unit "motor-reducer" in mechanical systems with a long service life under shock loads, for use, for example, as a motor wheels of environmentally friendly cars.

A technical solution according to the patent of the Russian Federation No. 2375806 is known. The essence is that the synchronous electric motor has a housing, a stator package with teeth and with a multiphase winding, a shaft, alternating coaxial hollow cylinders of the rotor and stator, consisting of ferromagnetic and non-magnetic elements located along the axis of rotation, and the rotor cylinders are mechanically connected to the rotor, and the stator cylinders - with a housing, while the teeth and ferromagnetic elements of the stator cylinders, as well as the teeth of the magnetic circuit and the ferromagnetic elements of the rotor cylinders have their same angular positions. A second stator package was introduced in the form of a hollow cylinder with teeth on its inner surface, located outside of the hollow cylinders, a shaft with a fast rotation rotor containing highly coercive permanent magnets in the form of rectangular parallelepipeds located radially, tangentially and counter magnetized, wedge-shaped pole tips located between hollow cylinders and a stator package with a multiphase winding having a reversed design.

The disadvantage is the design complexity and limited rotation speed due to the cantilever arrangement of the hollow cylinders, as well as the low reliability of work on a moving base.

A technical solution according to the patent of the Russian Federation No. 2544835 is known. The essence is that the synchronous motor with magnetic reduction contains a housing, a stator package with teeth and with a multiphase winding, a fast rotation rotor with permanent magnets on a shaft with bearings and a multi-layer slow rotation rotor on a shaft with bearings. The slow rotation rotor and the stator have alternating disks consisting of ferromagnetic and non-magnetic elements in the form of sectors, permanent magnets have the form of sectors and are magnetically axially magnetized with alternating polarity, the stator package is made in the form of two rings of electrical steel tape by winding located at the ends of the electric motor, false teeth with coils and crowns are installed on the end surface of the ring of the stator package, on the surface of the other ring there are wedge-shaped protrusions having their same angles stems dimensions and position with the ferromagnetic elements of the stator disk, wherein the number of ferromagnetic elements on the stator disk and z _c z _p rotor disk related by z _p z _c = 2p ± and angular dimensions of the ferromagnetic elements of the stator and rotor disks slow rotation are different.

The disadvantage is the presence of two shafts, which complicates the design, as well as the lack of an optimal ratio between the thickness of the permanent magnets and the thickness and number of working gaps, which reduces energy performance.

A technical solution according to the patent of the Russian Federation No. 2604058 is known. The essence is that the synchronous electric motor with magnetic reduction contains a housing, a stator magnetic circuit with teeth and a multiphase winding, a fast rotation rotor with permanent magnets and a bearing, a slow rotation rotor on a shaft with bearings and a stator have alternating disks, stator and rotor disks slow rotation consist of ferromagnetic and non-magnetic elements in the form of sectors, permanent magnets have the form of sectors and are magnetized axially with alternating polarity, the stator magnetic circuit is made in in the form of two rings of electrical steel tape by winding, located at the ends of the electric motor, false teeth with coils and crowns are installed on the end surface of the first ring of the stator magnetic circuit, and the number of ferromagnetic elements on the stator disk z _c and on the rotor disk z _p are related by z _p = z _c ± 2р, where p is the number of pairs of poles of the stator winding, and the angular dimensions of the ferromagnetic elements of the disks of the stator and the rotor of slow rotation are different, the bearing of the fast rotation rotor is mounted on the rotor shaft rotation and the thickness of the permanent magnets h _m on the fast rotor is related to the thickness and number of working gaps by the ratio h _m = 2mδ, where δ is the gap between the disks, m is the number of disks of the slow rotation rotor,

The disadvantage is the presence of axial force on the shaft of slow rotation due to asymmetry of the magnetic system, a large scattering flux due to the large MDS of the permanent magnet and a large number of paths, as well as the difficulty of cooling due to the location of the winding from one end of the electric motor, which reduces energy performance and reliability of the electric motor.

The closest technical solution to the claimed technical solution for the largest number of matching features and the achieved technical result, selected by the applicant as a prototype, is the invention according to the patent of the Russian Federation No. 2668817. The essence is that the synchronous electric motor with magnetic reduction contains a housing, a stator magnetic circuit with teeth and a multiphase winding, a fast rotation rotor with permanent magnets and a bearing, a slow rotation rotor on a shaft with bearings and a stator have alternating disks, stator and rotor disks slow rotation consist of ferromagnetic and non-magnetic elements in the form of sectors, permanent magnets have the form of sectors and are magnetized axially with alternating polarity, the stator magnetic circuit is made in in the form of two rings of electrical steel tape by winding, located at the ends of the electric motor, overhead teeth with coils and crowns are installed on the end surfaces of the first, second rings of the stator magnetic circuit, protrusions are made on the end surfaces of the tooth crowns, the position of which coincides with the ferromagnetic elements of the stator disks, and number of ferromagnetic elements on the stator disk and z _c z _p rotor disk related by z _p z _c = ± 2p, where p - the number of stator pole pairs and the angular dimensions Furr magnetic members of the stator disks and the rotor slow rotation are different, the rapid rotation of the rotor bearing is mounted centrally on the rotor slow rotation shaft, and the thickness of the permanent magnets h _m rotor rapid rotation is related to the thickness and number of transmission gaps ratio h _m = 2mδ, where δ - gap between disks, m is the number of disks of the rotor of slow rotation.

The disadvantage is the presence of even spatial harmonics in the distribution law along the gap of the magnetomotive force of the stator winding, which causes additional energy loss in the magnetic circuit.

The technical result, to which the claimed invention is directed, is to improve energy performance.

The technical result is achieved in that the synchronous electric motor with magnetic reduction, comprising a housing, a stator magnetic circuit with teeth and a multiphase winding, a fast rotation rotor with permanent magnets and a bearing, a slow rotation rotor on a shaft with bearings and a stator, have alternating disks, stator disks and slow rotation rotors consist of ferromagnetic and non-magnetic elements in the form of sectors, permanent magnets have the form of sectors and are magnetized axially with alternating polarity, the magnetic circuit stat The ora is made in the form of two rings of electrical steel tape by winding, located at the ends of the electric motor, patch teeth with coils and crowns are installed on the end surfaces of the first, second rings of the stator magnetic circuit, protrusions are made on the end surfaces of the tooth crowns, the position of which coincides with the ferromagnetic elements of the disks stator, and the number of ferromagnetic elements on the stator disk z _c and on the rotor disk z _p are related by the equality z _p = z _c ± 2р, where p is the number of pairs of poles of the stator winding, and the angles e the dimensions of the ferromagnetic elements of the disks of the stator and the rotor of slow rotation are different, the bearing of the rotor of fast rotation is mounted in the middle on the shaft of the rotor of slow rotation, and the thickness of the permanent magnets h _m on the rotor of fast rotation is connected with the thickness and number of working gaps by the ratio h _m = 2mδ, where δ - the gap between the disks, m is the number of disks of the rotor of slow rotation, has the number of stator teeth z = 6p, and the coils are wound around two adjacent teeth.

The claimed technical solution is illustrated by drawings (Fig. 1 - Fig. 7):

- in FIG. 1 - shows a longitudinal section of a synchronous electric motor with magnetic reduction;

- in FIG. 2 - shows a fast rotation rotor;

- in FIG. 3 - shows the stator disk;

- in FIG. 4 - shows the rotor disk of a slow rotation;

- in FIG. 5 - shows a view of teeth with coils;

- in FIG. 6 - shows the distribution law of the MDS winding of the prototype;

- in FIG. 7 - shows the distribution law of the MDS winding of the electric motor of the application.

The following are presented in detail the design features of the features shown in these figures.

In FIG. 1 shows a synchronous electric motor, where;

1 - housing; 2, 3 - bearing shields;

4, 5 - stator pack rings;

6, 7 - teeth;

8, 9 - coils;

10 - permanent magnet;

11 - sleeve rotor fast rotation;

12, 13 - stator bushings;

14, 15 - stator disks;

16, 17 - sleeve rotor slow rotation;

18, 19 - discs of the rotor of slow rotation;

20 - shaft;

21, 22 - slow rotor bearings;

23 - bearing of the rotor of rapid rotation.

The claimed design is assembled as follows. The housing 1 is rigidly connected with the bearing shields 2, 3. They are installed rings 4, 5 of the stator magnetic circuit. On the ring 4 there are twelve teeth 6 with coils 8. On the ring 5 there are twelve teeth 7 with coils 9.

Four permanent magnets 10 are mounted on the sleeve 11 of the fast rotation rotor. The stator disks 14, 15 are mounted on the stator bushings 12, 13 mounted on the housing 1. The slow rotation rotor disks 18, 19 are mounted on the slow rotation rotor bushings 16, 17 mounted on the shaft 20. The shaft 20 is supported by bearings 21, 22 mounted in the bearing shields 2, 3. The fast rotation rotor is mounted on a bearing 23 mounted on the shaft 20. The bearing 23 is wide and angularly resistant to provide the required position of the fast rotation rotor.

The rings 4, 5 of the stator magnetic circuit and the teeth 6, 7 are made of electrical steel tape by winding. The teeth 6, 7 with crowns look like sectors. They are installed on the rings 4, 5 of the stator magnetic circuit. Coils arranged diametrically are connected in series in the opposite direction and form three phases of the stator winding: A, B and C.

The fast rotation rotor has four permanent magnets 10 made of highly coercive hard magnetic material having the form of sectors (shown in shaded in FIG. 2) and non-magnetic sectors (not shaded in FIG. 2). Sectors are magnetized along the axis of rotation and form alternating poles on the end surfaces.

The stator disks 14, 15 have alternating sectors of soft magnetic material (shown in Fig. 3 as dark) and non-magnetic material (in Fig. 3 light). Magnetic elements are made of electrical steel.

The disks 18, 19 of the slow rotation rotor have alternating sectors of soft magnetic material (shown in Fig. 4 dark) and non-magnetic material (in Fig. 4 light). Magnetic elements are made of electrical steel.

The number of ferromagnetic elements of the stator disks z _c and ferromagnetic elements of the disks of the slow rotation rotor z _p per one pole division differ by one. In FIG. 3, 4, the case is shown when the number of pole pairs is p = 2, z _c = 20, z _p = 24.

Synchronous motor with magnetic reduction operates as follows. When a three-phase voltage system is applied to the stator winding, a rotating magnetic field with four poles arises. It carries with it a rotor of rapid rotation. Together with it, areas of large magnetic induction rotate in the disks of the stator and rotor of slow rotation. As a result, the slow rotation rotor is rotated so that the positions of coincidence of the positions of the ferromagnetic elements of the stator disks and the corresponding ferromagnetic elements of the disks of the slow rotation rotor are in the areas of maximum magnetic induction module.

For half the period of the supply voltage T / 2 = π / ω, the rotor of rapid rotation will rotate by an angle π / 2, and the places of the maximum magnetic induction module will be repeated. In this case, the rotor of slow rotation should turn by one sector, i.e. at an angle of 2π / z _p. Therefore, the magnetic gearbox has a gear ratio z _p / 4. Therefore, the rotational speed of the rotor of slow rotation will be ω _m = 2ω / z _p. Here ω is the angular frequency of the supply voltage. The moment on the shaft of slow rotation M _m = z _p M _b / 2.

The presence of several disks of the stator and rotor causes multiple deformation of the magnetic field in the zone of the disks, which increases the developed moment and allows to improve the overall dimensions.

On the end surfaces of the teeth crowns 6, 7, facing the active zone, there are wedge-shaped protrusions in the form of sectors, repeating in shape and quantity the ferromagnetic elements of the stator disks, which increases the developed moment.

In FIG. 5 shows teeth with windings. Coils A and -A are offset by an angle π / 2 and connected in series and in accordance. Coils B, -B and C, -C are respectively placed and connected respectively.

Ferromagnetic elements of the disks of the stator and rotor of slow rotation are made of electrical steel lined to reduce losses in the steel due to eddy currents, since during operation the magnetic induction in the sectors changes.

The moment transfer from the rotor of fast rotation to the rotor of slow rotation is elastic - through a magnetic field. With an increase in the load moment on the shaft of slow rotation, it lags by a certain angle from the position corresponding to idling.

The electric motor does not have mechanical contacts between the moving active parts, is silent in operation, has a long service life, determined by bearings, allows shock loads, since the connection between the rotors is through a magnetic field.

The specific energy of the magnetic field is determined by the expression

With a linear demagnetization curve, the maximum energy of the permanent magnet is achieved provided that the magnetic resistances of the permanent magnet are equal to the load, which is the gaps between the disks of the stator and the slow rotor rotor. This equality provides high energy performance and is satisfied if the thickness of the magnet is equal to the sum of the lengths of the gaps between the disks, i.e. when fulfilling equality

h _m = 2mδ,

where δ is the gap between the disks, m is the number of disks of the rotor of slow rotation.

The installation of the bearing 23 of the rotor of rapid rotation on the shaft 20 increases the base for the shaft and simplifies the design. The rapid rotation rotor reinforces the field created by the motor winding. Thanks to its placement in the middle and the placement of teeth with coils on both magnetic circuits, a symmetrical magnetic system is obtained and the axial force acting on the shaft is completely removed. Bearings 21, 22 are loaded only with radial forces, which reduces the starting voltage of the electric motor and increases its reliability.

The central location of the rotor of fast rotation with permanent magnets reduces the magnetic flux of scattering in the magnetic gearbox by about four times compared with the asymmetric placement. This increases the useful magnetic flux passing through the stator and slow rotor disks, which increases the maximum torque of the electric motor.

The power loss in the windings per one end of the electric motor is two times less than with the unilateral position of the winding, which facilitates cooling of the electric motor and increases its reliability.

In FIG. 6 shows the distribution of the MDF F (x) of the prototype at a time when the current in phase A is maximum. The first F ₁ (x) and second F ₂ (x) harmonics are shown. The magnetomotive force of one coil at a maximum current value is taken equal to 20 A.

In FIG. 7 shows the distribution of the MDF F (x) at a time when the current in phase A is maximum. The first F ₁ (x) and fifth F ₅ (x) harmonics are shown. The magnetomotive force of one coil at a maximum current value is taken equal to 10 A - two times less than in the prototype winding. The table shows the amplitudes of the spatial harmonics for the winding of the prototype with six coils and the claimed winding with twelve coils.

It is seen that the spatial harmonics of the MDS, multiples of three, are absent in both windings. The proposed winding lacks even harmonics. Odd harmonics, not multiple of three, in both windings coincide.

The rms value of the higher spatial harmonics of the MDS prototype and the claimed windings matter

It is seen that the claimed value of the current value of the higher harmonics of the MDS is 54.28% less.

The higher spatial harmonics of the MDS create similar harmonics of magnetic induction and cause additional magnetic losses in the steel of the stator and rotor. Therefore, the proposed winding has significant advantages in terms of efficiency.

Claims (1)

Magnetic reduction synchronous electric motor, comprising a housing, a stator magnetic circuit with teeth and a multiphase winding, a fast rotation rotor with permanent magnets and a bearing, a slow rotation rotor on a shaft with bearings and a stator have alternating disks, the stator and slow rotation rotor disks consist of ferromagnetic and non-magnetic elements in the form of sectors, permanent magnets have the form of sectors and are magnetized axially with alternating polarity, the stator magnetic circuit is made in the form of two rings of electrical tape of technical steel by winding, located at the ends of the electric motor, overhead teeth with coils and crowns are installed on the end surfaces of the first and second rings of the stator magnetic circuit, protrusions are made on the end surfaces of the tooth crowns, the position of which coincides with the ferromagnetic elements of the stator disks, and the number of ferromagnetic elements on the disk the stator z _c and on the rotor disk z _p are connected by the equality z _p = z _c ± 2р, where p is the number of pairs of poles of the stator winding, and the angular dimensions of the ferromagnetic elements of the disks the stator and the rotor of slow rotation are different, the bearing of the rotor of fast rotation is installed in the middle on the shaft of the rotor of slow rotation, and the thickness of the permanent magnets h _m on the rotor of fast rotation is connected with the thickness and number of working gaps by the ratio h _m = 2mδ, where δ is the gap between the disks, m - the number of disks of the rotor of slow rotation, characterized in that the number of stator teeth is z = 6p, and the coils are wound around two adjacent teeth.

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