SU1614071A1 - Device for loading electric power source - Google Patents

Abstract

The invention relates to electrical engineering, in particular to conversion devices, connecting two AC or AC and DC networks. The aim of the invention is to reduce the mass and cost of the device. The design of transformers (first and second) with a combined magnetic system is proposed, containing a magnetic system similar to the magnetic system of a conventional braked asynchronous machine with a stator 1, in the slots 2 of which three-phase primary and multiphase secondary windings of two transformers are laid, and the number of pole pairs of both transformers are different from each other an even number of times and the number of phases of the secondary windings is an odd number greater than three. The rotor 3 is made inhibited, smooth without grooves. Electric energy is consumed from the AC source and through the terminals of the first transformer is supplied to a controlled multiphase rectifier, which through an inverter driven by the network, the second transformer transmits electrical energy to another AC network. 1 hp f-ly, 3 ill.

Description

CPUl, 1

The invention relates to converter equipment that connects two AC mains to a million AC and DC mains, and can be used for testing primary 5 heat engines that drive an alternator and DC generator, as well as for factory or acceptance tests of autonomous generating devices (for example, shipboard) .10

The purpose of the invention is to reduce the mass and cost of the device,

FIG. 1 shows the proposed construction of transformers with a combined magnetic system; in fig. 2 is a circuit 15 of a coupled winding of a single transformer acting as a three-phase primary winding and a multi-phase secondary winding: FIG. 3 shows an external circuit diagram of the proposed device.

FIG. Figure 1 shows the design of a transformer with a combined magnetic system, containing a magnetic system (similar to the magnetic system of a conventional braked asynchronous machine) with a stator 1, in the slots 2 of which three-phase primary | e and multiphase secondary windings of two transformers, with the number of pole pairs of the windings of both transformers differing from each other by an even number of times, the number of phases of the secondary windings is an odd number greater than three, and the rotor 3 is braked, smooth, without grooves.

 FIG. 2 shows the combined winding 4 of one transformer, the total number of sections of which is divided without remainder into three and the number of phases of the secondary winding, the sections of the combined winding 4 are connected into 40 polygon, having through the first equal number of sections three-phase outputs of the primary winding, and through the other equal number of sections - multiphase leads 8-16 of the secondary winding, The number of phases of the secondary 45 windings is odd and ranges from 5 to 49. It is obvious that the primary and secondary windings of the transformer can be performed separately, without electric ktricheskoy communication therebetween, 50

FIG. 3 is a diagram of the external connections of the device proposed, comprising a transformer 17 with a combined magnetic system (transformer 17 contains three-phase terminals 5-7 of the primary winding and multiphase terminals 8-16 of the secondary winding of the first transformer and similar three-phase terminals 18-20 of the primary winding and multiphase terminals 21-29 of the secondary second transformer), an alternating current electrical power source 30 from which energy can be transmitted to an alternating current network 31 controlled by a multiphase bridge rectifier 32 and a multi-phase bridge-driven network inverter 33.

A transformer with a combined magnetic system (Fig. 1 and Fig. 2) operates as follows.

Structurally, the integrated transformer system of transformers is made in the form of a braked asynchronous machine with stator 1, grooves 2 (in which the primary and secondary windings of the first and second transformers are laid) and smooth without grooves with a fixed rotor 3 playing the role of a magnetic water conductor.

The primary and secondary windings of one transformer are laid in the same slots in order to use part of the scattering fluxes (to increase the magnetic coupling between the windings), as well as to eliminate the occurrence of electromagnetic moment on the rotor.

The rotor is made smooth, without grooves to simplify its manufacturing technology.

The transformer windings are made similarly to the primary winding of an induction machine, with the number of pole pairs of the windings of both transformers differing from each other by an even number of times, and the number of phases of the secondary windings is an odd number greater than three. The primary and secondary windings of one transformer can be made separately and combined (according to the autotransformer circuit).

The difference in an even number of times the number of pole pairs of transformer windings allows the use of the same magnetic system, which reduces the overall weight of the transformers. In the atom case, the transformers are not magnetically connected, since an even number of half-waves of the other transformer’s magnetic field is placed with the pole division of the transformer with a smaller number of pole pairs, respectively, for a transformer with a larger number of pole pairs, the magnetic field of the other transformer under the North and South poles has the same sign. As a result, the magnetic field of one transformer does not cause the appearance of DCS in the windings of another transformer.

To further reduce the mass and cost of the device, the primary and secondary windings of each transformer are combined into one combined winding 4 of a single transformer (Fig. 2). The combined winding 4 contains the total number of sections, which is divided without remainder into three and

the number of phases of the secondary winding is equal to ta. This is done in order to be able to make symmetrical conclusions of the primary three-phase and secondary phase windings (m 2 3). FIG. 2 shows that the combined winding 4, through the first equal number of sections, contains three-phase terminals 5-7 of the primary winding, and through another equal number of sections - multiphase terminals 8-16 of the secondary winding of the transformer. The use of combined windings makes it possible to save about 50% of the mass of the copper winding wire.

For the combined winding 4 of the transformer it is impossible to change the transformation ratio between the primary and secondary windings of one transformer. However, when testing the most common source of energy (alternating current), voltage matching is possible by changing the unlocking angle of the grid-driven inverter.

The device for loading an electrical energy source (FIG. 3) works as follows;

Electric energy is depleted from AC power source 30 and through terminals 8-16 of the first transformer is fed to a controlled multiphase bridge rectifier 32, which through a network-driven inverter 33, a second transformer with multiphase leads 21-29 and three-phase leads 18-20 transmits electrical energy to the network 31 AC.

The power factor of the AC power consumed from the source 30 is controlled by varying the unlocking angle of the thyristors of the controlled rectifier 32, since the power factor of the rectifier, while neglecting the switching angle of the valves, is equal to

cos 1 cos

The control of the magnitude of the transmitted current is carried out by changing the angle of unlocking of the thyristors of the slave of the inverter 33. The control circuits of the thyristors of the controlled rectifier and the slave of the inverter are typical.

In the case ({when the source of electrical energy is a direct current generator, the first transformer and the controlled rectifier 32 are not used. In this case, the generator is supplied with a direct current inverter 33, which is driven by a network, through a second transformer

gives electrical energy to the AC 31 network.

The proposed device differs from the known one in that the first and second transformers are made with a combined magnetic system (Fig. 1).

The number of t2 phases of the secondary windings of transformers is taken to be an odd number to increase the number of md ripples in the voltage of the dc circuit over a period. For odd mph, md 2m2, and for even m2, md m2.

The frequency of the harmonics of the rectified current is 15 fd (K) mdfiKd,

where fi is the mains frequency;

Kd - 1,2,3, ... is the order of the harmonic of the rectified current.

The frequency of the harmonics of the current consumed from the network is equal to

fi (K) (Kmd ± 1) fi ,,

where K is 1,2,3, ... is the order of harmonics of an alternating current consumed from the mains.

For example, when the number of phases is secondary. 25 coils of a transformer and a bridge rectifier (or inverter), equal to m2 2, the frequency of the pulsations of the rectified current circuit at fi 50 Hz is equal to fo (K) Kd 500 Hz,

30 and the harmonic frequency of the current consumed from the network is

fi (K) (K 500+ 50) Hz. If we accept m2 49, then accordingly fd (K) Kd 4900 Hz; f 1 (k) (K. 4900 4- 35 +50) Hz.

Consequently, the range of variation of t2 from 5 to 49 provides a practically feasible spectrum of suppression of higher harmonics from the side of constant and alternating currents.

Thus, with an increase in the number of phases of the secondary windings (and, accordingly, the numbers of the phases of the bridge rectifier and the bridge slave of the inverter network), the order of harmonics on the sides of the constant and alternating current of the rectifier and the slave of the inverter increases, which reduces the size, weight and the cost of coA corresponding filters. 0

The advantage of the proposed device is. (as compared with the known, which is also the basic object) is to reduce its mass and cost (by combining the magnetic systems of transformers, reducing the mass and cost of filters and increasing the order of the generated voltage and current harmonics).

Claims (2)

1. A device for loading an electrical energy source containing a first transformer with a primary three-phase winding connected to the AC input terminals and a secondary winding connected to the AC diagonal of the bridge rectifier, which is connected to DC by its DC terminals. the DC terminals of the bridge inverter, the second transformer with the primary three-phase winding connected to the output AC terminals, and the secondary winding connected to the diagonal m of the AC current In order to reduce the mass and cost of the device, the magnetic system of both transformers is combined and made in the form of a hindered asynchronous machine with a smooth, smooth and smooth stationary rotor, in the stator grooves of which three-phase primary and multi-phase secondary windings of both transformers are laid , the numbers of pairs of poles of the windings of both transformers differ from each other by an even number of times and the number of phases of the secondary windings is an odd number of more than three, the primary and the toric windings of each transformer are made to be combined, for the total number of sections of the combined winding without remainder is divided into three and the number of phases of the secondary winding, the sections of the combined winding are connected into a polygon having through the first equal number of sections three-phase outputs of the primary winding and through another equal number of sections multiphase conclusions of the secondary winding of the transformer. 2. A device according to claim 1, characterized in that the number of phases of the secondary winding is in the range of 5 to 49. (OutZ Fig.Z