RU2848350C1 - Electric motor stator with two rotors - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: stator of an electric motor with two rotors contains a magnetic circuit in the form of a contour with internal and external teeth, between which windings connected to an AC source are wound around magnetic circuit rods of varying thicknesses . Additional internal and external teeth are located on the side rods of different thicknesses between these windings, with magnetic shunts installed between them and one of the sides of the stator terminals. The magnetic circuit has an even number of main and additional teeth, and the windings located on different sides relative to each tooth are connected in opposition with the possibility of creating multidirectional magnetic fluxes.

EFFECT: improvement of energy characteristics.

8 cl, 3 dwg

Description

The invention relates to electrical engineering and mechanical engineering, in particular to electrical machines - stators of asynchronous and synchronous electric motors of single-phase and multi-phase alternating or unidirectional pulsed current with a sine wave approximation.

The main component of asynchronous and synchronous electric motors operating on single-phase and multi-phase alternating current or unidirectional pulsating current is the stator. This is in contrast to DC motors, where the main component is the rotor and commutator, and the stator acts as a permanent magnet. The rotor of asynchronous motors is typically a squirrel cage rotor, and in machines with heavy starting, it is phase-fed. Currently, stators are known, the operating principle of which is described in books on the theory and design of electrical machines.

The closest technical solution is given in patent RU 2723297 dated June 9, 2020 by Oleg Mikhailovich Trishin (UA), Viktor Grigorievich Skomorokh (UA), and Andrey Petrovich Kanyuka (RU), in which the stator is used in an electromagnetic motor with two (external and internal) squirrel-cage rotors. Among all the advantages of these stators in electric motors with two rotors, there is one significant drawback - the shielding of part of the stator pole pieces using a squirrel-cage turn - patent Elihu Thomson (Thomson, Elihu, "Alternating-Current Magnetic Device", US 428650 published August 8, 1888, issued May 27, 1890). Its application in low-power electric motors shows excellent technical results. However, in higher-power machines, its use poses challenges, as it requires a larger closed ring, which leads to a reduction in the stator tip's size and, consequently, a reduction in its mechanical strength. Furthermore, due to the increased volume of the short-circuited coil and its constant remagnetization, its heating increases, leading to additional heating of the entire stator magnetic circuit and, consequently, the electromagnetic coils.

The technical objective of this invention is to increase the efficiency of an electric motor, reduce the load on the network and increase the range of speed control, increase the cooling of the electromagnetic coils of the stator and its magnetic circuit, by reducing the reverse voltage arising on the stator coils of the electric motor, which arises from the action of variable magnetic forces of the rotor (electromagnetic electromotive force of the rotor) of the operating motor, reducing the reactive power of the asynchronous motor, providing the ability to regulate the speed and power of the electromagnetic machine by power supply with step or smooth regulation of voltage and frequency.

The technical result is achieved in an electric motor stator containing a magnetic circuit in the form of a contour with inward and outward-facing teeth, each with an even number. Windings are wound between these windings around the magnetic circuit. These windings are located on opposite sides of each pole tooth and are connected in opposite directions, thereby creating magnetic fluxes in different directions. To initiate operation of the electric motor, it is proposed to use a magnetic circuit with side bars of varying thickness and additional internal and external teeth located in the magnetic neutral zone. Magnetic shunts made of steel are installed on the additional teeth, on the side of the thickened portion of the magnetic circuit and the thickened portion of the stator pole piece. Thus, the magnetic shunts are positioned parallel to the electromagnetic coil located on the thickened portion of the side bar of the magnetic circuit. The coils on the side bar of the magnetic circuit are electrically connected in series or in parallel. Each electromagnetic coil can be made with a single or multi-layer multi-turn structure, with the multi-turn layers of the electromagnetic coil being electrically connected in parallel or series. Different combinations of electromagnetic coil electrical connections allow the electric motor stator to be used with different electrical parameters of voltage (V) and electrical flow intensity (A). The section of the magnetic circuit containing the inner and outer pole teeth is called the root of the teeth.

The magnetic circuit may have a circular shape, as shown in Fig. 1.

The pole teeth of the magnetic circuit and additional teeth on the magnetic circuit are directed inward and outward of the circuit.

The number of pole teeth on the stator magnetic circuit is always even and the number of additional teeth is also always even and their total number can vary, but not less than 8.

The pole teeth of the magnetic circuit may have pole tips or be without them.

Between one side of the pole pieces or pole teeth and the additional poles on the stator magnetic core rod, magnetic shunts made of steel are installed.

Additional teeth on the magnetic core rods and magnetic shunts between them and the sides of the pole pieces are installed so that the inner and outer rotors rotate in the same direction.

Additional teeth on the magnetic core rods and magnetic shunts between them and the sides of the pole pieces are installed so that the inner and outer rotors rotate in different directions.

The windings of the electromagnetic coils on the side rods (rod) can be connected in opposite series or in opposite parallel.

Each electromagnetic coil can be made as a multi-turn single-layer or multi-layer, and the multi-turn layers of the electromagnetic coil can have a matched series or matched parallel electrical connection to the core of the magnetic circuit.

Fig. 1 shows a stator of an electric motor with rods of different thicknesses and windings of electromagnetic coils on them in the shape of a circle.

Fig. 2 shows a front view of a section of an electric motor stator with magnetic core rods of varying thicknesses, having a circular shape.

Fig. 3 shows a side view of a section of an electric motor stator with magnetic core rods of varying thicknesses, having a circular shape.

The stator of the electric motor contains an annular magnetic circuit 1 (Fig. 1) in the form of a contour with pole teeth 2, 2.1 and 4, 4.1 with pole pieces 3, 3.1 and 5, 5.1 located on them with a corresponding air gap for a squirrel-cage or phase rotor. Between the inner and outer teeth 2, 2.1 and 3, 3.1, windings of electromagnetic coils 6, 7, 8, 9 are wound around the side bars of the magnetic circuit 1. Electromagnetic coils wound on one bar (6 and 8, 7 and 9) are called bar coils and are connected electrically in a coordinated series or in a coordinated parallel. To ensure starting of the rotor, the bars of the coils have different thicknesses. The width of the magnetic circuit under the electromagnetic coils is different: under electromagnetic coils 7 and 9 it is two times smaller than under electromagnetic coils 6 and 8. Magnetic circuit 1 has an even number of pole teeth 2, 2.1 and 4,4.1 and additional teeth 14, 14.1 and 16, 16.1. The windings of the electromagnetic coils 6 and 7, located on different sides relative to the teeth 2, 2.1, and the windings of the electromagnetic coils 8 and 9, located on different sides relative to the teeth 4, 4.1, are electrically connected in opposite directions with the possibility of creating differently directed magnetic fluxes 10 and 11, 12 and 13. Between the electromagnetic coils 6 and 8, on the side rod there is an additional magnetic tooth 14, 14.1 with magnetic shunts 15, 15.1 connected to the pole tips 3, 3.1 of the pole teeth 2, 2.1, and between the electromagnetic coils 7 and 9, on the second side rod there are additional magnetic teeth 15, 15.1 with magnetic shunts 16, 16.1 connected to the pole tips 5, 5.1 of the pole teeth 4, 4.1.

Let us consider an example of a specific implementation of an electric motor stator. In this example, the stator is used as part of an electric motor with two squirrel-cage rotors: an inner rotor 17 and an outer rotor 18 (Fig. 2 and Fig. 3). The magnetic circuit 1 is made from insulated laminated steel sheets with a rectangular contour, as shown in Fig. 1. The magnetic circuit 1 can also be manufactured using powder metallurgy technology. The stator magnetic circuit can be integral or composite. The magnetic circuit 1 has a classic rod shape and has pole magnetic teeth 2, 2.1 and 4, 4.1 instead of central rods. The number of pole magnetic teeth 2, 2.1 and 4, 4.1 and additional teeth 14, 14.1 and 16, 16.1 can be different, even, but not less than 8. With this form of magnetic circuit 1 in the gap between the pole magnetic tooth 2, 2.1, with the pole tips 3, 3.1, i.e. Between the base of these teeth, two multi-turn single-layer windings of electromagnetic coils 6 and 7 are wound, which are connected oppositely (in series or in parallel) with the possibility of creating oppositely directed magnetic fluxes 10 and 11. This means that winding 6 on one side relative to the pole magnetic teeth 2, 2.1 with pole tips 3, 3.1 creates a magnetic flux 10, which is directed oppositely relative to the magnetic flux 11 created by winding 7, located on the other side of the pole magnetic tooth 2, 2.1. Windings 6 and 7 are electromagnetic coils that create magnetic fluxes 10 and 11. Similarly, between the pole magnetic teeth 4, 4.1 with pole tips 5, 5.1, two multi-turn single-layer windings of electromagnetic coils 8 and 9 are wound, which are connected oppositely (in series or in parallel) with the possibility of creating differently directed magnetic fluxes 12 and 13. This means that winding 8 on one side relative to the pole magnetic teeth 4, 4.1 with pole tips 5, 5.1 creates a magnetic flux 12, which is directed oppositely relative to the magnetic flux 13 created by winding 9, located on the other side of the pole magnetic teeth 4, 4.1 with pole tips 5, 5.1. Windings 8 and 9 are electromagnetic coils that create magnetic fluxes 12 and 13. Windings 6 and 8, and correspondingly windings 7 and 9, located on the side rods of the magnetic circuit of varying thicknesses, are called rod magnetic circuits. These windings are electrically connected to each other in series or parallel. To ensure rotor starting, the side rods of the magnetic circuit have different thicknesses. The width of the magnetic circuit under the electromagnetic coils is different: under electromagnetic coils 7 and 9 it is two times smaller than under electromagnetic coils 6 and 8. On the lateral rods of the magnetic circuit 1 of different thicknesses between the rod windings 6 and 8 there are additional teeth 14, 14.1 connected to the pole tips 3, 3.1 of the pole magnetic teeth 2, 2.1 by magnetic shunts 15, 15.1, and between the rod windings 7 and 9 there are additional teeth 16, 16.1 connected to the pole tips 5, 5.1 of the pole magnetic teeth 4, 4.1 by magnetic shunts 17, 17.1. The complex interaction of opposing and concurrent magnetic fluxes on additional magnetic poles 14, 14.1 and 16, 16.1 allows them to have more powerful magnetic poles of the same magnetic polarity as those on the corresponding opposite ends of pole arcs 3, 3.1 and 5, 5.1. Depending on the connection method of the rod windings (6-8 and 7-9)—antiparallel or anti-series—the input parameters of the electrical power supplied to the motor change. With an anti-parallel connection with a higher supply voltage, the current is lower compared to an anti-series connection, in which the voltage is lower and the current supplied to the motor is higher. Due to the described connection of windings 6 and 7, magnetic teeth 2, 2.1 with pole pieces 3, 3.1 of magnetic circuit 1 are a clearly expressed north N, magnetic pole, and due to the connection of windings 8 and 9, magnetic teeth 4, 4.1 with pole pieces 5, 5.1 are a clearly expressed south S pole, changing their polarity over time according to an alternating sine wave or an approximation close to it. The rotor in an electric motor with the stator under consideration is located in the gap between pole pieces 3, 3.1 and 5, 5.1. Teeth 2, 2.1 and 4, 4.1 of the stator can have pole pieces 3, 3.1 and 5, 5.1 in the form of an arc, as shown in Fig. 1. Teeth 2, 2.1 and 4, 4.1 of the stator can be either solid or have teeth on the surface, or have a different shape, for example, a two-toothed, clearly defined pole.

The stator differs significantly from all existing stators with clearly defined magnetic poles. The difference is that electromagnetic windings 6, 7, 8, and 9 are not wound around teeth 2, 2.1 and 4, 4.1 (the conventional middle rods), as in armored stators. Instead, they are wound on the side rods (sides) of magnetic core 1, thus creating a rod-type electromagnetic stator. Windings 6 and 7 are wound between teeth 2, 2.1, and windings 8 and 9 are wound between teeth 4, 4.1. The difference from stators with armored stators is the placement of the electromagnetic coil windings: their electrical connection is performed in a coordinated opposite and coordinated parallel manner, while the electrical connection of the windings of rod windings 6-8 and 7-9 is performed in accordance with Ohm's law using opposite-series or opposite-parallel connections. The arrows on the magnetic circuit indicate the clockwise movement of magnetic fluxes Φ (in the upper half-cycle of the sine wave graph). When the direction of the supplied electricity changes in the opposite direction (in the lower half-cycle of the sine wave graph), the poles N and S change polarity to the opposite S and N. The opposite connection of the windings allows for the generation of opposite magnetic induction of the same polarity on magnetic circuit 1 between windings 6 and 7, as well as windings 8 and 9 (opposite magnetic fluxes - N-N or S-S). The section of magnetic circuit 1 between two oppositely connected electromagnetic windings 6 and 7 is called the root base of teeth 2, 2.1 and has one polarity around the entire circumference of the magnetic circuit—for example, N, i.e., the polarity on magnetic teeth 2 and 2.1 is the same as on their base. The second root of the tooth, located between windings 8 and 9 and teeth 4, 4.1, has the opposite polarity of the magnetic field S. Since single-phase or multi-phase alternating current with the shape of an electrical sine wave or a unidirectional pulsating current with an approximation of a sine wave is supplied to windings 6-8 and 7-9, an alternating magnetic field will exist on teeth 2, 2.1 and 4, 4.1 with a change in magnetic induction in accordance with the Faraday equation. Winding of windings 6, 7, 8, 9 between teeth 2, 2.1 and 4, 4.1 of magnetic circuit 1, that is, on the side rods of magnetic circuit 1, allows for more complete use of the stator iron to obtain the corresponding magnetic flux of electromagnets and to shift the magnetic characteristics along the hysteresis loop practically to the zone of complete magnetic saturation of the stator iron.

The pole teeth are arranged in pairs on the magnetic circuit, one of which (3) is directed inward through the circuit (2) of the magnetic circuit (1), and the other (4) is directed outward. This creates a magnetic flux that acts on two rotors—the inner (19) and the outer (20). This utilizes the generated magnetic flux more efficiently, increasing the conversion efficiency of electrical power into mechanical power.

The output shaft 18, as shown in Fig. 2, 3, is installed inside the housing 21 of the electric motor, closed at the end by a side cover 24. The shaft 18 is mounted on bearings 25 closed from the outside by covers 26. An internal squirrel-cage rotor 19 is rigidly fixed on the shaft 18. An external squirrel-cage rotor 20 is rigidly fixed on the shaft 18 through a flange 23. Both rotors are installed with the possibility of synchronous rotation on the shaft 18 of the motor. The stator 1 of the electric motor is stationary and is located between two rotors 19 and 20. The fastening of the stator and its centering are ensured through axes 22 located on the side cover 24. The stationary location of the side cover 24 in the housing 12 and the fixation of the stationary stator on it allow the free removal of connecting electric wires from the electromagnetic coils 6, 7, 8, 9. The junction electric box can be located both on the housing 21 and on the side cover 24. The base of the housing and the location of the junction electric box are not shown.

Since the windings of the electromagnetic stator coils are rigidly located on the stator magnetic circuit (side bars), the magnetic interaction of the magnetic fluxes arising in the bar windings 6-7 and 8-9 at the roots of the magnetic circuit teeth results in magnetic coupling of unipolar magnetic poles with a magnetic coupling coefficient M caused by counter magnetic fluxes of the same polarity at the root of the magnetic circuit teeth and which is common to both electromagnetic bar windings 6-7 and 8-9. When calculating the total stator inductance, the magnetic coupling coefficient M of bar windings 6-7 and 8-9 is taken into account with a minus sign, since the electricity in bar windings 6-7 and 8-9 flows in different directions. When calculating the magnetic flux Φ on stator teeth 2, 2.1 and 4, 4.1, the magnetic coupling coefficient M is taken into account with a positive sign, since the magnetic fluxes Φ 10-11 and 12-13 are directed towards each other, meaning their magnetic field is amplified. Reducing the stator inductance will significantly reduce the reactive power of the electric motor. The opposite connection of rod windings 6-8 and 7-9 with reduced inductance significantly reduces the reverse tension on rod windings 6-8 and 7-9 of the stator arising under the influence of the alternating magnetic field of the squirrel-cage rotor (the rotor electromotive force - rotor EMF). With the opposite connection of electromagnetic rod windings 6-8 and 7-9, their total electrical induction will be very small, therefore, their own inductive resistance will also be small. This reduces the supply voltage and the power supplied to the electric motor, thereby reducing the load on the electrical network.

Let's consider the stator of an electric motor in the operation of an asynchronous electric motor. The stator's operation in an electric motor strictly adheres to the laws of Ampere, Volta, and Ohm, as well as Coulomb's second law of magnetic poles, according to which two magnetic poles interact with a force proportional to the product of their quantities of magnetism and inversely proportional to the square of the distance between them. According to the same law, as with electric charges, like magnetic poles (S-S and N-N) repel each other, while unlike magnetic poles (S-N) attract. Considering that the electromagnets of the stator and rotor are arranged in a circle relative to each other, one of which is stationary (the stator) and the other rotates (the rotor), like poles push the rotor, while unlike poles pull it in. In this case, the proposed device makes maximum use of the magnetic field of the stator electromagnets and the different-thickness rods of the magnetic circuit with additional magnetic poles on them and the use of magnetic shunts that ensure the start-up of the short-circuited rotor, the reverse electrical voltage arising in the rod windings 6-8 and 7-9 is significantly reduced and its reactive power is reduced.

An AC electric motor is powered from the AC grid via power supplies (step-down autotransformers or electronic power controllers) or batteries, followed by the use of AC/DC converters. An asynchronous single-phase electromagnetic motor is powered by a unidirectional pulsed current with a sine wave approximation from the DC grid or battery, or via pulse motor control devices.

The effectiveness of the invention has been confirmed by testing prototype stators with rods of varying thicknesses in electric motors with single- and multi-phase alternating current and unidirectional pulsed current with sine wave approximation.

These electric motors will find the widest application in all sectors of the national economy, industry and all types of transport.

Claims (8)

1. A stator of an electric motor with two rotors, containing a magnetic circuit in the form of a contour with internal and external teeth, on which pole pieces are located, between which windings of electromagnetic coils are wound around lateral internal and external rods with different thicknesses of the magnetic circuit, connected to a source of alternating electricity, and on the lateral rods of different thicknesses between these rod windings there are additional internal and external teeth with magnetic shunts installed between these additional teeth and one of the sides of the stator pieces, changing the magnetic flux on the additional teeth, characterized in that the magnetic circuit has an even number of main and additional teeth (8, 16, etc.), and the rod electromagnetic windings, located on different sides relative to each tooth, are connected in a counter-clockwise direction with the possibility of creating multidirectional magnetic fluxes. 2. The stator of an electric motor according to paragraph 1, characterized in that the magnetic circuit has the shape of a circle. 3. The stator of an electric motor according to paragraph 1, characterized in that the magnetic circuit is integral or composite. 4. The stator of an electric motor according to paragraph 1, characterized in that the pole teeth of the magnetic circuit and the additional teeth on the rods of the magnetic circuit are directed inward and outward of the circuit. 5. The stator of an electric motor according to paragraph 1, characterized in that the additional teeth on the rods of the magnetic circuit and the magnetic shunts between them and the sides of the pole pieces are installed so that the inner and outer rotors rotate in the same direction or the inner and outer rotors rotate in different directions. 6. The stator of an electric motor according to paragraph 1, characterized in that the rod windings are connected in opposite series or in opposite parallel. 7. The stator of an electric motor according to paragraph 1, characterized in that each electromagnetic coil is made as a multi-turn single-layer or multi-turn multi-layer, wherein each multi-turn layer is considered a separate multi-turn electromagnetic coil. 8. The stator of an electric motor according to paragraph 1, characterized in that the windings of the electromagnetic coils on the rod are electrically connected in series or in parallel.