SU930529A1 - Ac voltage regulator and method of control of the same - Google Patents

Description

(54) AC VOLTAGE REGULATOR AND METHOD FOR ITS CONTROL

one

The invention relates to electrical engineering.

Voltage regulators are known that operate according to the add-on principle 2.

The disadvantage of these controls is limited functionality.

The closest to the present invention is an alternating voltage regulator containing a booster transformer, the secondary winding of which is connected between one of the input and output terminals, and one of the terminals of the primary winding is connected to the input outputs of the device via controlled full-wave switches consisting of of consistently connected thyristors and cut-off valves, between the common points of connection of which are connected coiling capacitors.

There is also known a method of controlling these regulators by means of commutation, shutdown of shut-off valves and the corresponding

thyristors of controlled two-cell keys, providing various modes of operation, primary winding of booster transformer from short-circuited to serial with mains, Gz circuit.

The disadvantages of the known regulator and method of control are the limited functionality and low stability of the regulator at switching angles smaller than the angle of the load current.

This is explained by the fact that the known regulator, when the windings of the booster transformer are agreed to turn on, provides only the voltage booster mode — the network, and to implement the voltage booster mode — the network needs to re-initiate one of the transformer windings. This limits its regulating properties when used as a voltage stabilizer.

In addition, in a known controller controlled by a known method, with

The load and switching angles smaller than the current shear angle (in the area of negative currents) the switching angle (adjustment) angle is limited to a critical angle equal to the load current shear angle. A decrease in the switching angle less than the current shear angle leads to a violation of a given symmetric form-formarovac law and an output voltage with a voltage boost or with a volt-boosting and, ultimately, unstable operation of the controller,

Consequently, limiting the regulatory properties (switching angle range and voltage control range) when using the regulator as the executive bodies of variable voltage stabilizers limits the functionality And reduces the operation stability at switching angles smaller than the load current shear angle

The purpose of the invention is to expand the functionality and increase the stability of the controller at 1 switching angle of a smaller shift angle of the load current.

The goal is achieved by the fact that in a well-known variable voltage regulator containing a booster transformer, the secondary winding of which is connected between one of the input and output terminals and one of the terminals of the primary winding is connected to the input terminals of the device via controllable keys consisting of consistently included thyristors and cut-off valves, between the common connection points of which the switching capacitors are turned on, parallel to each switching capacitor is connected A chain of counter-connected thyristors, the common points of which are connected to another terminal of the primary winding of the booster transformer (VDT).

In the proposed regulator, the primary winding is included in the diagonal of the bridge formed by the thyristors of the controlled keys and entered in the chains. This allows reversing it without additional reconnections, i.e. change the level of the output voltage up or down from the nominal mains voltage, while providing a voltage boost (summation of the voltages of the primary and secondary windings of the VDT) or the additive, (subtraction of the voltage of the windings of the voltage transformers). As a result, in the proposed reguptotor, the range of variation of the output voltage level is two times greater than in the known controller, which allows it to be used as an executive body of voltage stabilizers with enhanced functional capabilities.

However, the proposed controller stably operates with an active-inductive load only at switching angles equal to or greater than the angle of current shift and becomes inoperable at switching angles smaller than the angle of shift of the load current.

At the moment corresponding to the specified switching angle, the shut-off valve is opened and, according to the sequentially connected thyristor of the corresponding chain, with the voltage boost, and with the voltage boost, controlled keys increase the stability of the controller, in this case there is a free exchange of energy between the consumer and the power supply network and contours of the recharging of switching capacitors are provided, with the polarity necessary for the next switching, while ensuring reliable switching of the thyristors at any pairs load meters, and a symmetrical voltage in both half-periods is applied to the load over the entire range of switching angles.

Fig, 1 shows the functional diagram of the regulator; FIGS. 2 and 3 are timing charts of operation.

The device contains a booster transformer, the secondary winding 1 of which is connected in series with the load circuit 2, and the primary winding 3 is connected to the common terminal of the two controlled switches 4 and the common winding 3.

5 on the counter-parallel thyristors 6, 7 and 8, 9 connected to the terminals of the feed pair through the slam-shut valves Yu, 11 and 12, 13, respectively. Switching capacitors 14 and 15 are connected between common points of connection of thyristors 7 and 8 with shut-off valves 10 and 12 and thyristors

6 and 9 with shut-off valves 11 and 13

In parallel with the switching capacitors 14 and 15, chains of 16 19 19 counter-connected thyristors are introduced, the common points of connection of which are connected to another terminal of the primary winding 3 of the VDT.

Timing diagrams and the algorithm for the operation of the shut-off valves and thyristors (shaded areas correspond to the enabled state), explaining the operating principle of the control and how they control the switching angle of the load current shear n active-inductive load with a voltage boost and voltage gain, see figs, 2 and 3 respectively,

Load current curves 2O, power supply voltage curves 21, load voltage curves for boost and volt supplements, respectively 22 and 23, voltage curves for switching capacitors 15 and 14 for boost voltages and volts, 24, 25, 26, -27, respectively.

ripVi this designation of all other positions corresponds to the numbering of elements in FIG. one.

The proposed controller is operable with active and active-inductive loads. In the first case, uncontrollable valve-diodes should be used as 1CX.13 gate valves, and in the second case - thyristors.

The principle of operation of the regulator (Fig. 1) will first be considered at a current shift angle of 2 O, greater than the switching angle c (cL (; or uniquely associated with symmetrical (relative to the moment ct jr / 2} ways of controlling the angle by the ratio P –J / -at | (Fig. 2 and 3),

With a positive polarity of the mains voltage 21, at the moment the current 20 passes through zero, the slam-shut valves 10, 13 and the thyristors 7 and 19 of the control key 4 and the entered chain are simultaneously unlocked. Through the resulting serial circuit: network - 1O-7-3-1913 - the network begins to flow a current 20, coinciding in direction in the windings

I, 3 with the network voltage 21, and on the interval .oLjcK load 2 is applied the sum of the voltage of the network and the secondary winding 1 VDT - voltage 22 with wave1addition ..

At the switching angle c (, (c from the control circuit (not shown in Fig. 1)), there are unlocking pulses on the valve 11 and the thyristor 16. The latter also opens the capacitor 15, discharging along the circuit: 15-13 sets-1О-7 -3-16-15, the thyristor 19, which is connected in anti-series with the thyristor 16, is locked and recharged by the polarity of the voltage 24 (in FIGS. 1 and 2 in brackets). After that, the valve 13 goes out, the valve opens

II, and the contour of the short-circuited primary winding 3 VDT: 3-16J11-U-7-3, through which current flows.

2d in the same direction. Change . induction in the core of the VDT is delayed and a voltage 22 is applied to the load, equal to the voltage 21 of the network. 5 After changing the polarity, the voltage 21 (in Fig. 1 is in brackets) of the network at the moment oi-ji-i-Jf} .J-iin, corresponding to the specified switching angle, the triggering pulses again arrive at the shut-off valve

0 13 and a thyristor 19 in series with it, connected to one of the terminals of the primary winding 3 of the VDT and a coclining wiping capacitor 15, the second output of which is connected to the thyristor 16, switched on opposite to the unlocked thyristor 19, first opens the thyristor 19 and the capacitor 15 , recharging along the contour: 15-11-10-7-319-15, locks the thyristor 16, preparing it so that to work in the next period. When the recharge of the condenser 15 is completed, the valve 11 is closed and the valve 13 opens,

The current 20 flowing in the previous direction due to the self-induction EMF of the primary: 3-19-13-network-10 7-3 and the secondary 1 windings of the VDT with the voltage 21 of the network, drops to zero at oL 4i-jr. Gates Yu, 13 and thyristors

0 7 and 9 are locked and at the same time the gates 11, 12 and thyristors 6 and 18 opposite to them open simultaneously. The primary winding 3 of the VDT, Current

, 20, changing direction, flows in the interval +1 d.ci j4epe3 valve 12, thyristor 18, winding 3, thyristor 6, valve 11, as well as in the secondary winding. 1 and a voltage of 22 with a voltage boost is applied to the load.

At an angle of KONfMyTaHHH (valve 10 and thyristor 17, there are unlocking pulses and thyristor 17 is unlocked. Condenser 14 is reversed by voltage 25 to turn off thyristor 18. and is recharged by current 2O along the circuit: 14-17-3-6-11-ce-12 -14 by the polarity shown in Fig. 1 in a casing, after which the valve U is opened and extinguished

Q valve 12. The primary winding 3 of the VDT is closed in a short circuit: 3-6-11-10-17 3; as a result, on the “interval,” a voltage 22 is applied to the load 2, equal to the network voltage 21.

Claims (3)

At the moment corresponding to the specified switching angle, a valve 12 and a thyristor, 18, connected to one of the terminals 7 rtefiBHiHoft of the winding 3 VDT, are connected to the gate 12 (here as in the previous half-period with the output having a common point with 16 19 entered chains) and by a switching capacitor -14, the second terminal (lining) of which is connected to the thyristor 17, which is connected in opposite direction with the unlocked thyristor 18. First, the o-ring; Tirissor 18, and after recharging the condenser 14 TOKQM 2O to the converter: 14-18-3-6-11-10-14 polarity (indicated in Fig. 1, without brackets), the valve 12 is opened and the valve 1O is closed. Again the primary winding is connected & n to the mains. Here, the current 2O flowing counter to the network voltage 21 across the circuit: 3-6-11-network-12-18-3, drops to zero at the moment, the thyristors 6, 18 and the gates 11 and 12, respectively, are closed. In the next period, the processes are repeated. I From the above it can be seen that with control of Lenia, according to the proposed method, the regulator provides circuits for the free circulation of electrical energy between the load and the network, as a result of which a voltage symmetrical in the half-period, different from the mains, is applied to the terminal for the voltage taken from the secondary winding of VDT, the shape of the curve of which does not depend on the parameters of the active-inductive load (current shear angle) and the switching angle. If in order to provide a reactive power recovery circuit with a volt additive, the shut-off valve and the stringer connected with it are inserted into the chain forming the terminal of the bridge and the thyristor of the controlled key with this output of the primary winding of the VDT forming together with the second output of the primary winding of VDT another top of the bridge. I.1. The operation of the regulator in voltaic power is different only in that the currents in the primary and secondary windings of the VDT flow in opposite directions. This is ensured by unlocking the corresponding shut-off valves and thyristors, the algorithm of which is shown in FIG. 3 Here, also, when the control signals are applied to the shut-off valves and thyristors, the thyristors are first unlocked, capacitors are recharged and only at the moment when the voltage on the capacitor plates is equal to the supply voltage, the valves are opened and i either short-circuited or in series with the network, the VDT primary winding circuit. By mutually changing the angles — M Pd and ct, during each half-period, the regulator circuit automatically switches from the boost mode to the voltaic mode and vice versa. The capacitors are recharged by the load current and at any time point have the polarity necessary for reliable switching of the next thyristor. By the adjusting properties, such a thyristor controller approaches the devices on fully controlled keys. Claim 1. Voltage regulator containing a booster transformer, the secondary winding of which is connected between one of the input and output pins, and one of the terminals of the primary winding is connected to the input pins of the device via controlled keys consisting of consistent-connected thyristors and cut-off valves, between the common points of connection of which switched-on capacitors are switched on, characterized in that, in order to expand the functionality, parallel to each The commutating capacitor is connected to a chain of opposite-connected thyristors, the common connection points of which are connected to another output of the primary winding of a booster transformer. 2. The control method of the AC voltage regulator according to claim 1, which is regulator with switching angles smaller than the angle of the load current, at the time corresponding to the specified switching angle, the shut-off valve is opened and the thyristor corresponding to it is consistently connected to it th chains. Sources of information taken into account in the examination 1. The author's certificate of the USSR 432474, cl. q 05 G 1/30, 1974. 2. Author's certificate of SSSG 517122, cl. H O2 M 5/25, 1977. 3. Authors certificate of the USSR 541157, cl. Q05P 1 / 2O, 1H77. () 0F | 18.}