SU599323A1 - Sine-shaped ac -to-dc voltage converter - Google Patents

Description

one

The invention relates to converter technology and can be used in the development of secondary power sources of electrical equipment.

Converters of alternating sinusoidal voltage to constant 1. 2, 3 are known.

Their disadvantage is that at the moment of connecting the input source to the converter, a significant overload of this source over current is possible. The presence of overloads is due to the fact that at the moment of switching on the thyristor, the instantaneous value of the input source voltage can be quite large, and since the input filter capacitor at the time preceding turning on the thyristor is discharged, a current flows in this mode in the starting mode times the maximum value of the current source in steady state.

The presence of significant overloads of the input current source can lead to disruptions in the operation of other consumers connected to this source, due to power supply dips, and also necessitates the use of high power diodes in the input circuit.

The aim of the invention is to reduce the starting current source overload in the starting mode.

This is achieved by the fact that, in the proposed AC sinusoidal voltage converter, it contains a capacitor filter and a thyristor connected between this filter and an input source, a control transistor is connected between the base and the anode of the specified thyristor, the base of which is connected to its collector via a resistor and through a shunt transistor --- with the thyristor cathode, npii4eNi, the base of the grounding transistor is connected to the control collector (the transistor through separately connected dnistor and resistor.

five

 As a dynistor, a device with a small voltage can be used as a DINistor, the beginning of the charge of the filter capacitor corresponds to the point in time when the input source voltage is close to zero.

The scheme of the proposed Converter is represented pa drawing.

Claims (3)

It contains a toggle switch I, an input source 2 of an alternating sinusoidal voltage, a transducer 3, a load 4, a dynistor 5, a transistor b, a rectifier 7, cc ... dens. op 8 filter; a resistor t, a control transistor 10, a thyristor 11, a resistor 12, a capacitor 13. When the toggle switch 1 is connected to the source 2 of an alternating sinusoidal voltage, a converter 3 connected to the load 4 is connected. Suppose that the instantaneous value of the input source voltage exceeds voltage across the dynistor 5. In this case, dynistor 5 goes into a closed state and into the base of the shunt transistor b from source 2 through toggle switch 1, rectifier 7, filter capacitor 8, resistor 9 and switched distor 5 p the unlocking signal steps, so that the transistor 6 goes into a closed state, shunt the chain from the series-connected transitions of the base-emitter of the controlled transistor 10 and the base is the cathode of the thyristor 11. So the transistor 10 and the thyristor 11 are in the open state, the capacitor of the filter starts charging through parallel-connected high-resistance resistors 9 and 12. The constant charging time of capacitor 8 is sufficiently long, so that the voltage on this capacitor remains almost unchanged and remains close to to zero. The indicated states of the elements in the circuit are maintained until the voltage of source 2 decreases to a value close to zero. As soon as this voltage becomes close to zero, the dynistor 5 goes into the open state, the current in the base of the transistor 6 stops and, therefore, this transistor also goes into the open state and its shunting effect stops. Further, in the process of subsequent increase (in magnitude) of the voltage of source 2 (as long as this voltage does not exceed the voltage of the sampler of the distor 5), a triggering signal flows through the resistor 12 through the resistor 12, which causes current to appear in the thyristor base 11 and , as a consequence, the inclusion of this thyristor. The use of the proposed pre-decoder will significantly improve the mode of operation of the power source and greatly reduce the mutual influence of different consumers when they are connected to the specified source. For example, the voltage of the transistor 5 is equal to 208, and as the source 2, a standard single-phase AC network of 220 V 50 Hz is used. If the potential deviation of the network voltage to an increase in comparison with the nominal value is 10%, the maximum instantaneous value of the network voltage is 340V. In this case, the maximum current pulse of the input source when the converter connected to it, performed according to the new scheme, is at least 17 times less than when the converter is connected according to the known scheme. If a thyristor with a relatively low value of the permissible anodic voltage rise rate is applied in the converter, a small inductance choke by a reverse diode can be connected in series with the thyristor and a small capacitor across the thyristor. The converter can be made in the one-half-period version, when the rectifier 7 is excluded from the circuit, and the input source 2, the toggle switch 1, the capacitor 8 and the thyristor 11 form a series circuit. In this case, the thyristor 11 simultaneously performs the functions of an input rectifying diode and an element that provides an improvement in the starting mode of the input source. However, to protect transistors 6 and 10 from reverse-polarity voltages, a low-power diode must be included in the circuit common to resistors 9, 12 and collector of transistor 10. Claims of an AC sinusoidal voltage to DC converter containing a capacitor filter and a thyristor connected between this filter and an input source, characterized in that, in order to reduce the input source overload, the base and anode of the specified thyristor has a control a transistor, the base of which through a resistor is connected to its collector, and through a shunt transistor - to the thyristor cathode, and the base of the shunt transistor is connected to the control collector transistor through serially connected dynistor and resistor. Sources of information taken into account in the examination: 1. Lecorgie J. Controlled electric valves and their application, Moscow, Energiya, 1971, p. 456-457. 2. USSR author's certificate number 426228, cl. H 02 M 7/20. 3. USSR author's certificate number 468343, cl. H 02 M 7/20. I