SU549794A1 - AC Voltage Regulation Device - Google Patents

Description

one

The invention relates to the field of electrical engineering and can be used in electrical installations with a load connected via a transformer.

A device for controlling an alternating voltage is known, comprising a transformer with a sectioned secondary winding, having lower and higher switching stages, and thyristor short-time switches associated with said steps. A disadvantage of the known device is low energy performance when connected to the output of the last consumer (load), adjustable with a lagging angle of shift.

The purpose of the invention is to increase the energy performance of the device.

The goal is achieved by the fact that the anode and cathode of the thyristors of each of the keys of the lower control cone are connected to the direct current terminals of the corresponding diode bridge, the alternating current terminals of which are connected in parallel to the corresponding lower stage section through the switching LC circuit.

FIG. Figure 1 shows a schematic diagram of the proposed device when one of the thyristor switches of the first step is connected to the DC terminals of the diode bridge; in fig. 2-circuit diagram

the regulator at the connection of both low-level switches to the terminals of the current of diode bridges; in fig. 3 - voltage diagrams, as shown below, operation of the device on FIG. one.

The device for controlling the alternating voltage contains a sectioned transformer 1 with an unseparated winding 2 and a sectioned winding with sections 3, 4, 5. The winding 2 is permanently connected to the network. Section 3 through a switching chain of droplets 6 and capacitor 7 is connected to the AC bridge terminals on diodes 8-I, to the DC terminals of which thyristor 12 cathode and thyristor anode 13 are connected. Switchable terminal of section 4 is connected to non-switchable output of section 3 with power a key from anti-parallel thyristors 14, 15. A non-switchable output of section 4 is connected to a switchable output of section 3 using a key on anti-parallel connected thyristors 16, 17. A load 18 is connected to a non-switchable by one clip by the th output of section 3, and the other with the output of section 5, the other output of which is connected to the non-switchable output of section 4.

The circuit in FIG. 2 differs from that of FIG. 1 in that the anode of the thyristor 16 n the cathode of the thyristor 17 of the second key of the lower stage

connected to the direct current terminals of the second bridge on diodes 19-22; to the terminals of the alternating current through a switching circuit containing a choke 23 and a capacitor 24, a second switchable section 4 is connected.

The device (Fig. 1) in the steady state operates as follows. At the beginning of the positive half-period of the mains voltage (Fig. 3a), the thyristor 14 is connected, connected in series to section 3, 4 at the highest stage of output voltage regulation (Fig. 36), between the cathodes of diodes 8, 9 and the anodes of diodes 10 of the charged capacitance (Fig. 30) and section 3. The diode 8 is open, and a voltage (Fig. 3d) is applied to the anode of the thyristor 12 in the unlocking direction, equal to the voltage of the charged capacitance 7 (Fig. 3b). When control pulses are applied to the thyristor 12, it opens and the capacitance 7 discharges along the circuit 7, 8, 12, 14, 6, 7. The discharge current of the capacitance 7 flows through the thyristor 14 in the opposite direction, it closes and - a blocking voltage is applied (Fig. 3g, 2, 1), equal to the sum of the voltages of the throttle and the capacitor 7, then an oscillating recharge of the capacitor 7 occurs along the contour 7, 8, 12, 4, 5, 18, 3, 6, 7 , preparing the work of the scheme in the next half period. After recharging the capacitance 7, the diode 8 closes (Fig. 3A), and the diode 9 opens (Fig. 3A). The control pulse for turning on the thyristor 16 is applied with some delay in relation to the moment of switching off the thyristor 14, sufficient to restore its control properties. Sections 3, 4 are connected in parallel, and a lower stage voltage is applied to the load 18. In this way, switching from a higher stage of regulation to a lower one, giving a leading angle of shift, takes place. In the other half period, the scheme works in a similar way.

When switching the voltage from the higher stage to the lower one (Fig. 1), only one switched section is connected to the load for some time and flows through it

all load current. After the second thyristor switch is turned on, the transition process of current redistribution between sections 3, 4, determined by the time constants of sections 3, 4, begins. Consequently, for some time one of the sections and one of the lower-level thyristor switches are overloaded.

In the diagram in FIG. 2 lower stage thyristors are turned on simultaneously. When the lower stage thyristors are turned on, the switching capacitors 7, 24 are simultaneously discharged through the high stage thyristor, including it. After recharging tanks 7, 24, sections 3, 4 are almost simultaneously connected in parallel with each other and the load. Therefore, in the circuit of FIG. 2 there is no overloading of the thyristors of the transformer sections, and, therefore, the circuit has increased reliability. Otherwise, the operation of the device in FIG. 2 is similar to the operation of the device in FIG. one.

The proposed device for controlling alternating voltage with a leading shear angle allows generating reactive power into an alternating current network, compensating for the reactive power consumed from the network with a lagging shear angle.

Claims (2)

1.Avt. St. № 318923 in class. G 05F 4/29, 1971. 2. Avt. St. No. 333544 on cl. O05R 1/20, 1972. LU 12 13 SW i: j. e t