SU892617A1 - Device for regulating m-phase ac voltage - Google Patents

Description

The invention relates to electro. technology, in particular, conversion technology, and can be used to regulate, stabilize and balance the m-phase alternating voltage.

Known devices for regulating the m-phase alternating voltage, containing as the executive bodies power voltodilators ₍ overhead transformers, the primary windings of which are connected through the switches to line voltages fl] and [2].

These devices have good technical and economic indicators, but the functionality is limited, since they can only be used in the mode of regulation and stabilization of the output voltage modulo.

The closest known device is a device containing booster transformers2, the primary windings of which are connected to the input terminals, and the secondary windings are connected between the input and output terminals, switches and control units by the number of phases [33.The device has the disadvantage of limited functionality, since it cannot used in the regulation and stabilization phase of the voltage phase.

The purpose of the invention is the expansion of functionality.

This goal is achieved in that the device for regulating the m-phase voltage, containing boost boost transformers, the primary windings of which are connected to the input terminals, and the secondary ones are connected between the input and output terminals, the switches and control units according to the number of phases, contain 2p boost boost transformers for each phase the primary windings of each pair of which, through the corresponding switches, are connected to the input terminals of different line voltages, and the secondary windings form a series circuit, connected between the input and output terminals of this phase.

In FIG. 1 shows a functional diagram of the device for the case of regulation of a three-phase AC voltage; in FIG. 2 - timing diagrams explaining the principle of voltage regulation on voltage transformers; in FIG. 3 ~ 5 - vector diagrams for the first voltage harmonics in various operating modes of the device.

The device (Fig. 1) contains boost boost transformers 1-6, having primary 7 ~ 12 and secondary 13-18 windings, and switches 19 "30 with control units 31" 33. The switches are made, for example, according to the bridge circuit on fully controlled keys 34-49 with two-sided conductivity so that one diagonal of each bridge is connected to the ends of the winding, and the second diagonal to the corresponding terminals of the network (load).

Consider the principle of operation of the device by the example of voltage regulation of one phase A (Fig. 2A).

In the control unit 31, pulse sequences are formed with the lagging ctp and leading β _ρ relative to the reference sequence 51 (Fig. 2 b), the control angles and are fed to adjacent keys of the switch 19: the lagging sequence 52 (Fig. 2 c) to the keys 40 and 38, and the leading sequence 53 (Fig. 2 g) to the keys 39 and 41. In this case, the line voltage of the network 50 (Fig. 2a) is converted to a high-frequency voltage 54 (Fig. 2 e), which is regulated and transformed into the secondary winding 13 of the boost transformer 1 .Bi-half in The rectification of the output voltage of the transformer 1 carries out the switch 25 on the keys 34-37. To do this, a reference sequence of pulses 51 is supplied to its opposite keys 34, 37 and 35, 36. With this control, voltage 55 is generated at the output of the bridge switch 25 (Fig. 2 g) and all the necessary operating modes of the boost transformer 1 are provided: maximum voltage boost, regulation voltage boost, direct forward mode

892617 4 chi, regulation of voltotag, maximum voltotag.

The maximum voltage boost mode is achieved by combining the phase of all ₅ three sequences of control pulses 51-53 (ar = 0, ftp = 0). At the output of the bridge switch 25, an undistorted sinusoidal voltage is formed, which is in phase with the linear voltage to which the bridge switch is connected.

By shifting the pulses 52 and 53 to a certain angle of regulation (el _p and 15 ftp), an adjustable voltage boost mode is achieved.

By increasing the control angles olp and [bp to a quarter of the high-frequency voltage period, the undistorted transmission mode ₂₀ to the load of the mains voltage is obtained, i.e. the voltage at the output of boost booster transformer 1 is zero, since the keys 38, 39 25 or 40, 41 are simultaneously closed, shorting the primary winding 7. At the same time, the simultaneous closure of the keys 34, 37 or 35, 36 provides a direct transmission of the mains voltage to the load.

zo

A further shift of the pulses 52 and 53 by an angle of regulation greater than a quarter of the high-frequency voltage period is ensured by the regulated voltage-drop mode, the limit ³⁵ case of which is the maximum voltage-drop mode with the control angle cLp and ji _p equal to the half-period of the high-frequency voltage. In this mode, pulses 52 and 53 are in phase with each other, but out of phase with pulses 51. An undistorted sinusoidal voltage is generated at the output of the MFST switch 25, which is in antiphase with the linear voltage to which the bridge switch 19 is connected. voltage boost transformer 2 circuits, and ⁵⁰ voltage regulation on voltage boost transformers 1 and 2 is carried out without phase shift. We will consider the further operation of the device in accordance with the vector diagrams for the first 55 harmonics of the output voltage shown in FIG. 3 “5, where ^ .υ ^, Ιΐς, are the voltages in the phases of the supply network;

^and _a A ° C · θ5ι »ΰ _αο? ΰ _α8 ι - voltage in phases at the output of the device;

voltage in the secondary circuits of boost transformers;

Θ is the angle of rotation of the three-phase voltage system.

Suppose that boost-up transformer 1 operates in boost mode and its primary circuit is connected to a linear voltage of 11d ^, and boost-up transformer 2 operates in voltage-drop mode and its primary circuit is connected to a linear voltage and ^ d. In this case, the voltage at the output of the transformer 1 coincides in phase with the linear voltage 1) d ₈ , and the voltage at the output of the transformer 2 is out of phase with the linear voltage U _tA . In this case, the voltages at the output of transformers 1 and 2 are equal in absolute value (Ιϋ ^ ΐ) = (I θ c ') After geometric summation of the vectors of these voltages with the voltage vector of phase A (Au), a new vector is obtained, which is the output voltage of the phase A (U _d ) (Fig. 3)

From the analysis of the vector diagram it is seen that the magnitude of the output voltage is greater than the input, while the phase value of the output voltage remains unchanged in the entire control range. If the boost-up transformer 1 operates in a voltage-boost mode, and the boost-up transformer 2 is in the boost-voltage mode, then the voltage at the output of the transformer 1 is in antiphase with the line voltage and the voltage at the output of the transformer 2 is in phase with the line voltage U _CA. The modules of these voltages are also equal to each other. 8, in this case, based on the vector diagram in FIG. 3, the magnitude of the voltage at the output of phase A is less than the magnitude of the input voltage. Output voltage phase value

892617 6 also remains unchanged over the entire control range.

If it is necessary to rotate the three-phase voltage system by an angle Θ, the boost transformers 1-6 are switched to the boost mode and, adjusting the output voltage modules of the boost transformers in appropriate proportions, rotate the phase-voltage system by an angle without changing the input voltage in accordance with the diagram given in FIG. 4.

When the boost boost transformers in various modes, the magnitude and phase of the output voltage are simultaneously regulated in accordance with the diagrams in Fig. 5.

Claims (3)

The invention relates to electrical engineering, in particular, to a converter technique, and can be used to regulate, stabilize and balance a t-phase alternating voltage. There are known devices for regulating t-phase alternating voltages, containing as executive bodies power boost transformers, the primary windings of which are connected via line voltage switches 1 and 2. These devices have good technical and economic indicators, but their functionality is limited, since they can be used only in the mode of regulation and stabilization of the output voltage modulo. The closest known device is a device containing booster transformers, the primary windings of which are connected to the input pins, and the secondary ones are connected between the input and output pins, switches and control units according to the number of phases 31. The disadvantage of the device is its limited functionality. as it cannot be used in the mode of regulating and stabilizing the voltage phase. The purpose of the invention is to expand the functionality. The goal is achieved by the fact that the device for regulating the t-phase voltage, which contains booster transformers, the primary windings of which are connected to the input terminals, and the secondary windings are connected between the input and output terminals, the switches and control units by the number of phases, for each phase 2p booster transformers, the primary windings of each pair of which through the corresponding 3 switches are connected to the input terminals of different linear voltages, and the secondary windings form a sequential ep nym connected between the input and output terminals of the phase. FIG. Figure 1 shows the functional diagram of the device for the case of regulation of a three-phase alternating voltage; in fig. 2 - timing diagrams that illustrate the principle of voltage regulation on voltage transformers; in fig. 3-5 - vector diagrams for the first harmonics of voltages in various operating modes of the device. The device (Fig. 1) contains add-on transformers 1-6, having primary 7-12 and secondary 13-18 windings, and switches 19-30 with control units. Switches are made, for example, by bridge circuit on fully controlled keys with two-way conductor. By the way, one diagonal of each bridge is connected to the ends of the winding and the second diagonal is connected to the corresponding network (load) terminals. Consider the principle of operation of the device on the example of adjusting the voltage of a single phase A (Fig. 2a). In the control unit 31, pulse sequences are formed with lagging ctp and leading flp relative to the reference sequence 51 (FIG. 2 b), adjustment angles and fed to adjacent switches of switch 19: lagging sequence 52 (FIG. 2 c) to keys 40 and 38, and leading sequence 53 (fig. 2 g) to keys 39 and 41. With this linear voltage of network 50 (fig. 2a), it is converted to high-frequency voltage 5 (fig. 2 d), which is regulated and transformed into the secondary winding 13 of the booster transformer 1. full-wave Straightening the output voltage of the transformer 1 is performed by the switch 25 on the keys. To do this, opposite keys are 3, 37, and 35, the ST is applied to a reference sequence of pulses 51. With this control, a voltage 55 is generated at the output of the bridge commutator 25 (Fig. 2 g) and all necessary operating modes of the booster transformer 1 are provided: maximum add voltage , control of voltage boosters, forward mode, regulation of voltootbavka, maximum voltootbavka. The maximum voltage boosting mode is achieved by phase matching all three sequences of control pulses 51-53 (cLp O, (Lp 0). At the output of the bridge switch 25, an undistorted sinusoidal voltage is generated that is in phase with the linear voltage to which bridge switch. By shifting the pulses 52 and 53 by one adjustment angle (aLp and p), an adjustable boost voltage is achieved. By increasing the control angles dp and | Lp up to a quarter of the period of high-frequency voltage, the mode is obtained undistorted transmissions of network voltage to the load, i.e., the voltage at the output of booster transformer 1 is equal to zero, because the keys 38, 39 or 0, 41 are simultaneously closed, shorting the primary winding 7. At the same time, the shorting of the keys 3k, 37 or 35 36 provides a direct transfer of the mains voltage to the load.A further shift of the pulses 52 and 53 by the adjustment angle, greater than a quarter of the period of the high-frequency voltage, provides an adjustable voltaic mode, the limiting case of which is the maximum voltaic mode at where the cip is adjusted and | bp is equal to the half-period of the high-frequency voltage. The pulses 52 and 53 in this are in phase with each other, but in antiphase with pulses 51. At the output of the MST-switch 25, an undistorted sinusoidal voltage is generated that is in antiphase with a linear voltage to which the bridge switch 13 is connected. Similarly, a control process in a booster transformer 2, the voltage being controlled at booster transformers 1 and 2 is performed without a phase shift. Further operation of the device will be considered in accordance with the vector diagrams for the first harmonics of the output voltage presented in FIG. 3-5, where tJAfUj ,, bQ, are the voltages in the phases of the supply network; 5 and, U., 0- - voltages in phases at the output of the device; 95iVlO: o8 voltage in the secondary circuit of booster transformers; 9 - rotation angle of the three-phase voltage system. Suppose that the booster transformer 1 operates in the booster mode and its primary circuit is connected to a linear voltage, and the booster transformer 2 operates in the voltaic mode and its primary circuit is connected to a linear voltage. In this case, the voltage at the output of the transformer 1 coincides in phase with the linear voltage Idc, and the voltage at the output of the transformer 2 is out of phase with the linear voltage. In this case, the voltage at the output of transformers 1 and 2 are equal to each other modulo (liJij l) () After geometrically summing the vectors of these voltages with the voltage vector of phase A (Od), a new vector is obtained, which is the output voltage Phase A (Ud) (Fig. 3) From the analysis of the vector diagram, it can be seen that the value of the output voltage is greater than the input, while the phase value of the output voltage remains constant throughout the entire adjustment range. If booster transformer 1 operates in voltaic mode and booster transformer 2 operates in booster mode, then the voltage at the output of transformer 1 is out of phase with linear voltage Ud, and the voltage at the output of transformer 2 coincides in phase with linear voltage yld The modules of these voltages are also equal. In this case, the output from the vector diagram in Fig. 3 is that the voltage at the output of phase A is less than the value of the input voltage. The value of the phase of the output voltage 76 also remains unchanged over the entire control range. If it is necessary to rotate the three-phase voltage system by angle b, the booster transformers 1-6 are switched to boost mode and, by adjusting the output voltage modules of the booster transformers in appropriate proportions, rotate the system of the phase-voltage voltage by an angle without changing the input voltage voltage in accordance with the diagram in FIG. k. When booster transformers operate in different modes, the magnitude and phase of the output voltage is simultaneously controlled in accordance with the diagrams in Fig. 5. Claims An apparatus for regulating a t-phase alternating voltage, comprising booster transformers, the primary windings of which are connected to the input terminals, and the secondary windings are connected between the input and output terminals, switches and control units according to the number of phases, characterized in that expansion of functionality, it contains for each phase 2p booster transformers, the primary windings of each pair of which are connected to input pins through appropriate switches ase line voltages, and the secondary winding form a series circuit connected between input and output terminals of the phase. Sources of information taken into account in the examination 1. The author's certificate of the USSR tr, cl. G 05 F 1/22, 1976 (prototype). 2. USSR author's certificate fP 382216, cl. H 02 R 13 / Ot, 1972. 3. Authors certificate of the USSR (G 318137, class, G 05 F 1/22, 1972. Phi.1 SO otp sz J3p S3 X FIG. 2