SU1495940A1 - Electric machine with excitation from permanent magnets - Google Patents

Abstract

The invention relates to electrical engineering and can be used as a power source in power plants driven by gas turbines or other engines with an unstable rotational speed. The aim of the invention is to improve the accuracy of stabilization and to expand the range of adjustment of the output voltage of the machine. The generator inductor is made of two identical parts, which can mutually turn in opposite directions with axial displacement of the internal rod-pusher, with which both parts of the inductor are connected by a screw drive with right-handed and left-handed threads. The rod is displaced by a control electric motor, the rotor of which is connected via a screw gear to the pusher rod. The motor is controlled by commands from the control unit when a mismatch appears between the output and the reference voltage. 2 Il.

Description

The invention relates to electric machines driven by permanent magnets, and can be used in synchronous generators, direct current generators or generators for a mantle-valve system for generating a frequency-variable drive (variable speed - constant frequency) driven by power units, frequency the rotation of which is constant, as well as in adjustable DC valve motors with a wide frequency range of regulation.

The purpose of the invention is to improve the accuracy of stabilization and to expand the range of adjustment of the output voltage of the machine in generator mode at varying speed and load.

FIG. 1 shows a structural diagram of an electric machine, a longitudinal section; in fig. 2 is a schematic diagram of an actuator with reciprocating motion of a rotor.

An electric machine with excitation from permanent magnets contains a stator 1 with a magnetic core 2 and a winding box 3, a rotor 4 consisting of a solid inner shaft 5 and two

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hollow J3HeuiHHx shafts 6 and 7 with identical magnetic conductors 8 and permanent magnets 9 with alternating poles fixed on them, with both external shafts 6 and 7 mounted on the internal shaft 5 movably in the tangential direction by means of two helical gears - the right 10 and left-handed 11, the Mai'mna also contains a device 12 for turning the poles, consisting of a rod of the pusher 13 fixed movably relative to the stator 1 in the axial direction. connected with the internal shaft 5 through the bearing 14, controlled by the first static voltage converter 15 and the actuator motor 16, the rotor 17 B: is connected with the push rod 13 with the screw gear 18, and the main F winding 19 is connected to a controlled static converter; 15, the control input 20 of which is connected to the output 21 of the adder 22 and I to an external command device 23. The internal shaft 5 is connected to an external drive by splined engagement 24 with the possibility of axial movement. To eliminate the possibility of rotation, the push rod 13 is provided with a tab 25, located inside the chute 26 on the body 27 of the machine. For controlling the machine, it contains sensing elements of the control system in the form of a sensor 27. The output voltage, the sensor 28 of the rotational speed of the rotor 4, the sensor 29 of the winding current of the core 3, connected to the signal adder 22.

For the voltage stabilization mode, the reference voltage source 30 is connected to the adder 22.

It is possible otherwise with an electromagnetic actuator, in which the pusher rod 13 is made in a form, it is the continuation of the internal shaft 5, and the rotor 17 of the executive electric motor 16 is stationary. mounted on a push rod 13 and has at least one disk magnet 31 magnetized axially and having pole ends at the ends — tips 32, outside of which there are stationary main windings 19 of the executive electric motor 16 and the circumference of their annular magnetic circuit 33.

0 5 0

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An electric machine with permanent magnet excitation operates as follows.

In the generator mode, the torque from the external drive is transmitted through the spline gearing 24 to the shaft 5 and through the screw gears 10 and 11 to the magnetic cores 8 and the magnets 9. When the rotor 4 rotates in the windings of the core 3, the emf is variable, the frequency, and the amplitude of which depends at a constant load from the rotational speed and relative position of the rotor poles 4. If the winding voltage of core 3 measured by voltage sensor 27 does not correspond to the specified value determined by the signal of the reference voltage source 30, then the signal From the output of the sum-, the signal math 22 is fed to the control input 20 of the adjustable static converter 15 voltage NIL and to the main winding 19 of the electric motor 16, which causes the rotor 17 to rotate and the rod-pusher 13 to move axially due to the screw engagement 18 Due to the mutually opposite directions of the screw engagement 10 and 11, the magnetic cores 8 with the magnets 9, which do not have axial displacement, rotate in opposite directions relative to the shaft 5. This results to a change in the net magnetic flux of the excitation, and therefore to a change in the output voltage on the winding 3. Since the voltage control system has negative feedback, then the output voltage is the same. This approach tends to a given stable value with changes in the frequency of rotation of the drive and the load of the generator in their design ranges. The winding current sensor 29 ykor 3 and the rotational frequency sensor 28 provide high speed and high quality voltage transients for the stabilization of voltage during sharp disturbances. The device 12 turning the poles (Fig. 1) works as follows. When the rotor 17 rotates the executive motor 16, the rod-pusher 13 is axially moved due to the self-braking helical gear 18 and key 25 sliding inside the groove 26. Axial force from the rod The pusher 13 is transmitted to the shaft 5 through the bearing 14, and its value is determined by the frictional force in the helical gears, the Ishitz gear 24 and other surfaces, the slip, and the force of inertia.

The device 12 of the rotation of the poles works only when. voltage deviation from the set, which determines its efficiency. As a result of the high reduction ratio of the win- ter-18T transmission 18, the accuracy of stabilization and voltage regulation is increased, the electromagnetic torque and the mass of the engine 16 are reduced.

The device 12 of the rotation of the poles (Fig .. 2) works in the following way. When voltage is applied to the core winding 19, an axial force is applied to the inductor — a permanent magnet 31 with tips 32, rigidly connected to the shaft 5, and causing it to move and rotate the poles with the magnet 9 in a given direction. If there is no resynchronization signal and voltage on the winding 19, the shaft 5 should be held in the position in which it remained at the disappearance of the voltage, as long as there are no longitudinal forces in the moving system due to, for example, the load of the generator (axial components of electromagnetic the forces acting on the semi-inductors are mutually compensated due to the opposite directions of the helical gears 10, 11). If, under the action of any factors, axial force and displacement of the shaft 5 appears, this results in the appearance of a control signal and its development. Such an implementation of the executive engine 16 can provide higher speed and greater accuracy, due to the absence of the screw gear 18 and the bearing 14, but the force generated by such a linear motor is less.

If regulation of the machine voltage Bbt is required at any given time law or in a predetermined function of time, shaft rotation frequency, winding core current, etc., then an appropriately generated signal must be sent from an external command device 23 to the control input 20 an adjustable static voltage converter 15, for which a limestone power amplifier, an inverter control and other static converters can be used.

In the event of an emergency mode, for example, a short fire hazard in the winding of the machine core 3, an external command device 23 or winding current sensor 29 from the external control device 29 sends a signal of a magnitude and duration to which the opposite poles coincide with the control input 20 of the static converter 15. the other, and the resulting magnetic flux of excitation becomes zero. There is no need to use a special distributor for the drive and driven shafts. However, in case of more dangerous malfunctions, for example, when the bearing assemblies are out of operation, it is possible using the device 12 to turn the poles to bring the shaft 5 of the rotor 4 of the machine out of engagement with an external drive device, i.e. disconnect spline engagement 24.

When using a machine as part of a valve engine, it is also possible to deeply regulate its excitation magnetic flux with a signal from an external command device 23 or from the sensitive elements. In this case, the excitation flow can be adjusted from zero to maximum value.

Claims (1)

The proposed electric machine has a higher voltage stabilization accuracy compared to the known one, in which the stabilization or regulation of the output voltage is based on the properties of elastic elements (springs), the input of the element into the centrifugal regulator, whose rigidity and non-linearity depend on the ambient temperature, from the variation in the spring parameters due to technology, as well as random combinations of the rotor speed of the machine and load parameters. In the proposed electric machine, the error of stabilization or regulation of the output voltage is determined mainly by the gain in the feedback loop of the control system and therefore can be significantly reduced. Invention Formula Electric maiptna with excitation from permanent magnets, containing a stator with a magnetic core and a core winding, a rotor consisting of a solid inner shaft and a first hollow outer shaft, moving in the tangential direction relative to the inner shaft, first and second identical magnetic circuits with permanent magnets with alternating Tolus, the first of which is rigidly fixed on the first floor external shaft, a device for turning the poles and sensitive elements, in order to increase the accuracy of one hundred bilization and) broadening of the regulation range;} the output voltage, one .seal and two angular contact bearings, as well as the second hollow bearing, are introduced into the machine 1 | external shaft, movable in tangential relative to the inner shaft and coupled to it by means of a right-handed screw engagement, the first hollow outer shaft is flax with the inner one by means of a left-handed screw engagement, with the hollow outer shafts separated by a thrust bearing and pressed against each other by angular contact bearings, a turning device poles made in the form of an electromagnetic actuator with an output movable element, combined with the internal shaft with the possibility of axial reciprocating two-way voltage, and sensors through an automatic control system associated with elektromapshtom actuator. 16 3Z J3 FIG. 2