SU762100A1 - Electric motor - Google Patents

Description

The invention relates to electric drives, more specifically to electric machines with contactless switching.

Known electric motors whether valve, which comprises a stator U-shaped in the axial plane magnitopro- water ⁵ on which there are sections of the armature winding [1]. The rotor of this electric motor rotates in bearings ..

• also known motors with switching gate, which ^{functions, 0} tion engine combined with features electromechanical system gnitnogo suspension rotor [23. This motor is technically closest to the proposed motor. It comprises a stator with a U-shaped magnetic cores in the axial plane in which pole protrusions are fixed permanent magnets, and _m are placed on the coils connected in sections, and connected to a power source through a switch valve, and a rotor, the active part of which is in the form

2

ferromagnetic segments separated by non-magnetic gaps. Permanent magnets are also placed in the grooves of the ferromagnetic segments, with the permanent magnets of the rotor and stator facing each other with like poles. Functionally, the device combines a valve-switched electric motor and a rotor suspension system using electromagnetic repulsive forces. Its advantage is simplicity and reliability, since the rotor suspension system is stable without the use of external devices for automatic control of the air gap size.

The main disadvantage of this electric motor is the small amount of torque, since it is determined by the difference of the tangential components of the electromagnetic forces acting on the rotor in its individual zones. In some cases, the rigidity of the suspension may be insufficient, since the centr 762100 4

The force acting on the rotor with changes in the gap is determined by the difference in radial electromagnetic repulsive forces acting in diametrically opposite zones.

The aim of the invention is to increase the torque and improve the quality of the electromagnetic suspension of the rotor.

This is achieved by having y. electric motor containing a rotor and a stator With a magnetic core, made in the form of axial ferromagnetic packages evenly distributed around the circumference with windings placed on them connected to a power source, a black switch ^is controlled by an Angular Position Sensor, the rotor contains two alternating-pole excitation systems with by shifting the axes of the poles around the circumference of the rotor by the magnitude of the pole division, shifted relative to each other in the axial direction, so that their outer surfaces are located opposite in the pole protrusions of the axial ferroma of the stator package in the stump. The magnets of these two excitation systems, whose axes are in the same axial plane, face the rotor surface with their opposite poles and form an alternating pole axial excitation system. The motor valve switch can consist of separate links, each of which is a reversible power amplifier, with a load in the form of one of the stator windings, so that the total number of: ... links is equal to the number of specified windings, and the switch control circuits are connected to the output. common rotor angular position sensor and with the output of one of the sensors of the gap between the rotor and the stator, evenly placed around the stator circumference. - Such an electromechanical device: functionally combines vigatels ventilnoykommutatsiey and system electromagnetic rotor suspension. The resulting system electromagnetic forces have radial components, used for operation of the suspension system, and the tangential component, creating the torque of the electric motor, the radial and tangential components can be adjusted in ^size! and direction independently and. with a minimum of mutual influence.

ten

15

20

thirty

35

50

55

25

40

45

FIG. 1 shows the proposed electric motor, a cross-section; in fig. 2 - the same longitudinal section; in fig. 3 - constructive option, which ensures the stability of the suspension of the rotor at its axial displacements; in fig. 4 - linear scan of the rotor and stator; in fig. 5, 6, 7 - the principle of force interaction between the elements of the stator and the rotor taking into account the currents in the stator windings; in fig. 8 - functional:. motor circuit with valve switch.

The active part of the stator of an electric motor consists of a magnetic core, representing a system of axial ferromagnetic packages 1 (Fig. 1-7), for example, P-type or C-shaped, uniformly distributed around the stator circumference, and of the stator windings 2 (Fig. 1 -7), made in the form of coils. The rotor 3 of the electric motor (Fig. 1-7) contains two alternating-pole excitation systems using permanent magnets.

FIG. 1 shows a four-pole electric motor, so that the magnitude of the pole division in this case is 90 degrees. The electric motor has two such systems of excitation (Fig. 2), shifted relative to each other in the axial direction, so. that their outer cylindrical surfaces are opposite the pole ^: * protrusions of the ferromagnetic stator packages. The magnetic axes of each pair of poles of the two excitation systems lie in the ' _: one axial plane, as shown in FIG. 2, but these poles have different polarity. Thus, the magnetic field lines of the two excitation systems can close as. in planes perpendicular to the axis of rotation of the rotor, and mainly in axial planes passing through the axis of rotation (since the length of the average line of force in the axial direction is less, and this length does not depend on the number of poles of the excitation systems). Structurally, the rotor can be made, for example, in the form of a ferromagnetic sleeve, in the external grooves of which there are fixed magnets of the corresponding polarity, preferably with a high value of the coercive force. · Ta Kim, in · the pole pitch within ΐ ^- one end of the rotor adjacent, for example, permanent magnets,

, reference to the inner surface of ST5 7621 (

torus with its north, to the other torn - with its south poles.

The motor shown in FIG. 1 and 2, does not ensure the stability of the rotor suspension with its axial displacements, 5 since there are forces that tend to push the rotor out of the stator. To ensure axial stability, you can use two similar magnetic systems of the stator and, accordingly, two rotor systems fixed on a common base 4 (Fig. 3), provided that their working surfaces are inclined relative to the end surface of the rotor at an angle about not equal to 15

zero or 90 degrees Such a constructive option ensures the stability of the suspension with radial and axial displacements of the rotor.

The stator windings 2 may be integrated into sections, as shown in FIG. 4 (connection of the leads of the windings 2 among themselves is shown by a dotted line). A section is a series connection of windings 2 placed on magnetic wires, separated from each other at a distance equal to pole aiming ению ". The total number of windings 2 (and magnetic wires) is equal to the product of the number of poles and the number of stator winding sections Fig. 4 shows one of the sections, the rest are made quite similarly. The sections are included in the circuit of the valve switch, controlled by the rotor angle position sensor (in Fig. 1, ₃₅

2, 3 not shown).

^ However, a more preferable version of the design is possible, in which the individual windings 2 are not combined in sections, and each of them separately hell is included as a load in the corresponding link of the valve switch. Such unit represents a reverse power amplifier which provides current control magnitude in the winding n Changing its direction (for example differential or bridge circuit for thyristors or transistors powered from a DC source or an AC source ₅₀ You are a straightening).

FIG. 8 shows a functional diagram of the device corresponding to a four-pole electric motor, having sixteen ferromagnetic packets 1 and ₀ on the stator, therefore sixteen windings, four within each pole target.

X) 6

The following notation is entered in the diagram: 5 - a rotor angular position sensor, for example, of a transformer type, the number of outputs being equal to the number of packages 1 or windings 2 within one pole division; 6, 7, 8, 9 sensors for the size of the air gap between the rotor and the stator (inductive, resonant, capacitive or any other; in this case, the number is equal to the number of poles of the excitation system and they are installed uniformly around the stator circumference at a distance equal to the pole the division., ΐ; in Fig. 1, 2, 3 not shown); 10-25 - parts of the valve switch with a load in the form of one of the stator windings.

The control circuit of any valve switch is connected to one of the outputs of the rotor angular position sensor and to the output of one of the gap sensors. Each of the outputs of the rotor angular position sensor controls simultaneously all links of the switch, the loads of which are used for the windings 2 of the stator spaced from each other by the magnitude of pole division, ΐ, for example, links 10, 14, 18, 22. Each gap sensor controls the links the switch, the load of which is the windings placed on the ferromagnetic packets arranged in a row along the arc of the stator circumference equal to the pole division, within which the corresponding gap sensor is also placed. For example, sensor 6 controls links 10, 11, 12, 13 of the switch.

The motor works as follows.

Made of magnetic material packages 1 with windings 2 are electromagnets that interact with the permanent magnets of the rotor. If the windings 2 are combined into sections, then the direction of the current in the windings of the sections at each moment is such that two adjacent windings separated from each other at a distance, equal to ь, create axial magnetizing

forces (n. with.) mutually opposite directions. Directions n. with. shown in FIG. 4 within the sections of packages 1 inside the circles, and the direction of the current is the arrow. The windings of the remaining sections are included in the same way (not shown in Fig. 4), and the current in one of the sections, the windings of which at the considered moment of time are on the switching lines A-A, pa ⁷ 762100 8

veins zero. Thus, an axial alternating-pole magnetic system of the stator is created: within each pole division, £ n. with. all windings act according to, within any neighboring pole divisions - counter. The time-sequential switching of currents in the stator sections according to the signals of the rotor angular position sensor provides for the formation of a rotating field synchronously with the rotor of the stator field (as in conventional valve motors). Moreover, if during the rotation, within the area of each pole of the rotor, the permanent magnets of the rotor and and

The electromagnets of the stator face each other with their like-called "bows," a mode of synchronous rotor suspension arises with the use of electromagnetic repulsive forces. The power lines of the magnetic fields of the rotor and stator in this field are shown in the axial direction as shown in FIG.

5 (dotted line), and the spatial shift between the switching line A-A and the axis 25 of the rotor pole is half the pole division. The rotating electromagnetic moment in this mode is equal to zero. If the specified spatial shift (indicated by y in Fig. 4) is less than z 2/2, but not equal to zero, a mode occurs when the rotor acting on the rotor pole of the magnetnum ^ 'SYTEG has the radial components, which provide a total repulsion of the rotor from the stator 35, and the tangential components, which create an electromagnetic torque. Under the condition y –O, the magnetic fields shift of the rotor and stator is ^ /: 2, with 49 this creates a torque, but can't The rotor suspension is required. Thus, the normal mode of this electric motor is the mode, with ~ κ6τэнρό1ί'ement '' ^ '"is equal to, but' 45

close enough to ΐ / 2, as shown in FIG. four,

Regulation of the rotation speed of the electric motor is achieved by

changes in the spatial position of the 50 switching line with respect to the axis _

rotor poles (t. e. adjusting the moment when the rotor angular position sensor design allows for this possibility), and also in the determination divided least $ ₅ by adjusting the power voltage of the stator windings. The latter method is possible, since at I constant load moment the current in the windings in steady state does not depend on voltage, therefore, when adjusting the voltage, the operation of the suspension system is not significantly disturbed.

Suspension system on the principle of repulsion is simple, does not require the use of sensors to control the gap between the rotor and the stator, provides static stability. However, it is characterized by a significant drawback: at any displacement of the rotor axis relative to the geometric axis of the stator, when on one side the gap between the rotor and the stator decreases, and from the diametrically opposite, increases, the total; The restoring (centering) force is equal only to the difference between the repulsive forces in the direction of repulsion, which makes a sufficiently rigid suspension system difficult. Such a disadvantage is also inherent in the electromagnetic suspension system built on the principle of attraction of ferromagnetic bodies to the poles of an electromagnet, since the direction of action of the force of attraction does not depend on the direction of current in the electromagnet winding.

However, a system built on the principle of the interaction of an electromagnet with a permanent magnet (or two electromagnets with each other) allows you to change the nature of the interaction force even without changing the direction of the current in the electromagnet winding, but only by controlling the amount of current (FIG.

5, 6, 7). For a sufficiently large amount of current in the winding 2 of the electromagnet, the force lines of the magnetic fields of the stator and the rotor are closed mainly by the Air gap, as shown in FIG. 5, creating a repulsive force of like poles of magnets. When the current in the winding decreases (i.e., when the electromagnet has a smaller nanosecond compared to the internal nanosecond permanent magnet), a system of lines of force arises, closing along the electromagnet and the permanent magnet, and therefore repulsion decreases (fig. 6), and at some current values (even zero, the current) is replaced by gravity. Finally, when there is no current in the winding, the electromagnet turns into a ferromagnetic body, which experiences a force of attraction from the side of the permanent magnet (Fig. 7).

When the direction of the current changes and its further growth, the force of attraction continues to grow. However, this mode cannot be used in this design ^ k—

• '• ΐ **

θ 762100 10

because the moment of changing the direction of the current in the windings is determined by the order of switching according to the signals of the rotor angular position sensor and, therefore, cannot be arbitrary. _five

The possibility of changing the direction of the force acting in the electromagnet system - a permanent magnet, without changing the direction of the current in the electromagnet winding allows you to create a system that provides the rotor weight, in which the restoring force, if necessary, would be the sum, and not the difference of electromagnetic forces acting in diametrically opposite zones . If the gap 15 is reduced from any side compared to its average value, the current in the windings of electromagnets located in this zone should increase or at least remain constant, which will lead to an increase in repulsive force. On the opposite side, the gap increases, and the current in the windings of the corresponding electromagnets should decrease, which will lead to a decrease in the repulsive force 25, and with significant radial deviations of the rotor - and to the appearance of the force of attraction of the rotor to the stator. It is in this mode that the reducing force is equal to the sum of the electromagnetic forces acting in diametrically opposite zones.

To measure the size of the gap, it is necessary to use sensors that monitor the gap in a certain area. The smallest number of such sensors is 35. Each of them measures the average value of the gap within the third part of the stator circumference. With a small number of poles (for example, four) it is convenient to choose 40 the number of sensors equal to the number of poles.

The design of the electric motor and its work are characterized in this case by the following features. The windings 2 are not combined into sections, but each are included as a load in a separate link of the valve switch. Thus, the magnitude and direction of the current in each coil ⁵⁰ can regulirovat- Xia independently. The marked structure of the system (Fig. 8) allows you to organize the management process as follows.

Switching currents in the windings, i.e. ⁵⁵

change their direction, is carried out only by the signals of the sensor 5 angular

rotor position.

At the same time, the currents in all windings are located with spatial shift equal to H, t, e. In those that were originally combined into a single section, in which the simultaneous switching of currents in all windings was provided automatically by virtue of their series connection. Thus, from the point of view of the organization of the switching process, the considered design variant is no different from the initial one, except that the current can be regulated independently in each of the individual currents, and not in each section, as before. From the point of view of regulating the magnitude of the current, the windings are divided into other groups according to the number of gap sensors. The windings of electromagnets located in the zone where the gap is monitored by one of the sensors are combined into one group, and the current is self-regulated by the signals of this sensor. Therefore, the rotor angular position sensor provides synchronous rotation of the alternator magnetic field of the stator and the selection of the spatial position of the switching line with respect to the axis of the rotor poles during this rotation, and the gap sensors regulate the magnitude and voltage of the radial components of the electromagnetic forces in certain spatially moving 'zones in the vicinity of the sensor itself. This allows you to create a system of electromagnetic suspension of increased rigidity · while maintaining the possibility of controlling the speed and electromagnetic torque of the electric motor.

Thus, the device combines a valve-switched electric motor and a rotor suspension system using electromagnetic forces of both repulsion and attraction while maintaining the possibility of controlling the motor itself and the suspension system with minimal mutual influence. The quality of the suspension is most provided by the use of permanent, magnets with a high value of coercive force.

The considered principle of the electric motor can be implemented in a number of design options. It is possible, for example, a similar electric motor with an external rotor and an internal stator. In addition, linear times

. ¹¹ 7621

the motor coil shown in FIG. 4, can be considered as a linear electric motor ensuring the mutual movement of its elements and the suspension of the moving part $

over the guide element. It should also be noted that when choosing y (fig. 4), it is possible to use the mode of operation of the electric motor, in which the radial oscillating electromagnetic forces acting on the rotor poles will be the forces of attraction. Sustainability of the suspension can be ensured in this case only by using an external system for controlling the size of the air gap. It is possible to use the device with a torque equal to zero, i.e., as a "magnetic bearing".

The feasibility of applying the proposed design is determined by its features, consisting in the absence of support bearings and an extremely small friction torque. It can be used in precise systems, 25 mAh regulation and control, to create high-speed electromechanical devices. In the linear version, the design can be used to create vehicles with electro-3θ magnetic suspension of the crew.

Claims (2)

Claim 35 1. An electric motor containing a rotor and a stator with a magnetic core made in the form of axial ferromagnetic packages evenly distributed around the circumference with _40- mi winding placed on them, connected to a power source through a valve switch, controlled by a rotor angle sensor, characterized in that , in order to increase the torque and improve the quality of the electromagnetic suspension of the rotor, the rotor contains two variable-pole excitation systems with a shift of the axes of the poles around the circumference of the rotor by in pole division, axially displaced relative to each other, with the outer surfaces of the variable-pole rotor systems opposite the pole projections of axial ferromagnetic stator packages, and the magnets of two excitation systems, whose axes are in the same axial plane, face the rotor surface with their opposite poles d form a variable-pole axial excitation system. 2. Electric motor on π. 1, characterized in that it is equipped with sensors for the size of the air gap, its valve switch consists of separate links, each of which is made in the form of a reversible power amplifier, to the output of which a stator winding is connected, and the total number of links is equal to the number of specified windings, and the control circuits The switch units are connected to the output of a common rotor angle sensor and to the output of one of the sensors for the gap between the rotor and the stator, evenly placed around the stator circumference.