SU1457118A1 - Variable current source - Google Patents

Abstract

The invention relates to the field of electrical engineering and can be used to stabilize and regulate the current in the load. The purpose of the invention is to expand the functional capabilities by increasing the range of adjustment, as well as reducing the weight and size of the device. The device contains a series-connected inductive-capacitive converter (IEP) 1, a matching transformer 2, a rectifier 3, a thyristor controller 4, as well as filter 5 cables and a load 6, connected by a reverse diode 10. Location of the thyristor controller torus 4 in the dc circuit and its proposed circuit, including choke 9, parallel 12 and series 10 diodes and switching circuits with an additional power source 16, provide an increase in the conversion frequency, reduction in mass and dimensions and races widening of the regulation range, on the one hand, by disconnecting the load from the energy source simultaneously with shorting the output of the IEP, and on the other hand, by providing resonant load current stabilization based on the IEP and the thyristor controller operating in common. This provides a range of load variation from short circuit to nominal value. 1 hp f-ly, 2 ill. with SO | |; a sd-ch

Description

The invention relates to electrical engineering and can be used in converter equipment to stabilize and regulate the current in a variable load, for example, to supply various electric arc loads.

The purpose of the invention is to expand (the functionality by increasing the range of adjustment, as well as reducing the weight and size of the device.

FIG. 1 is a schematic diagram of a three-phase adjustable current source; in fig. 2 - stress diagrams at characteristic points of the device.

FIG. 2 shows: Uf, - voltage across the capacitor; 1ts - current

loads; U - finding on the corresponding thyristor.

An adjustable current source (Fig. 1 contains a series-connected inductive-capacitive converter (IEP) 1 fed from a three-phase network, a matching transformer 2, rectifier 3, thyristor regulator 4, filter choke 5 and load 6. The 8 thyristors of the thyristor regulator 4 are connected through the positive terminal of the rectifier 3 through the choke 9. A reverse diode 10, a shunt filter choke 5 and a load 6, is connected between the cathode of the thyristor 8 and the anode of the serial diode 11, whose cathode It is connected to the negative terminal of rectifier 3. The anode of diode 12 is connected to the cathode of thyristor 7. Successively connected switching choke 13, capacitor 14 and charge thyristor 15 are connected to terminals of an additional power supply 16, and choke 13 connected to the positive terminal of the power supply 16, the thyristor 15 to the negative terminal of the power supply 16, and the capacitor 14 is connected between the cathodes of the thyristors 7 and 8.

Adjustable current source (Fig. Works as follows.

Inductive-capacitive converter 1 converts the mains voltage source into a current source and mains energy through a matching transformer 2 and rectifier 3 is fed to

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thyristor controller 4, loaded on load 6 with filter choke 5. It is assumed that until the time point tg (Fig. 2) thyristor 8 was in a conducting state, the current of the IEP was driven through the load, and capacitor 14 was charged with polarity indicated in FIG. 1 in brackets.

The cycle of operation of the thyristor controller 4 p is assumed from the time t, when the thyristors 7 and 15 are simultaneously unlocked. The discharge current of the capacitor 14 flows towards the anode current of the thyristor 8 and, short-circuited through the opened thyristor 7, locks the thyristor 8 at the time equal to-. the zero of its total anode current. The load current 1c at this closes through diode 10. The output current flows through the choke 9, thyristor 7 and diode 12. The load in this mode is disconnected from the power source by the locked thyristor 8. Through the open thyristor 15 an oscillatory recharge of the capacitor 14 from the additional power source 16 occurs on the circuit: + power supply 16 - choke 13 - kondenkatot) 14 - thyristor 15 - - power supply 16. At time t, when the capacitor is charged with polarity. indicated in FIG. 1 without brackets, the thyristor 15 is locked. Diode 11. At this stage of operation, it prevents shorting of the capacitor plates.

At time t, (Fig. 2), the thyristor 8 is unlocked. The discharge current of the capacitor 14, flowing towards the anode current of the thyristor 7, locks it. At the same time, choke 9 prevents the short circuit of capacitor 14 through diode 12, diodes of microphone 3 and thyristor 8. Then capacitor 14 is quickly recharged via circuit: rectifier 3 - choke 9 - thyristor 8 - capacitor 14 - diode 12 - - rectifier 3. After this, the output current of the IEP is closed only through load 6, in series with which two throttles 9 and 5 are turned on, Throttle 9 serves to filter the high frequency component of the current of the pulse regulator, preventing its penetration into the IEP elements . The throttle filter 5 smoothes the ripple of the load current. Diode 12 at this stage of operation prevents the discharge of a capacitor.

ten

31457118

14 on the load, increasing the switching stability of the circuit during abrupt load drops or short circuits.

At time tj (Fig. 2), the thyristors 7 and 15 are unlocked and the processes in the controlled current source are repeated.

The magnitude of the average value of the load current is controlled by modulating the duration of the open state of the thyristor 8 in accordance with the selected control law.

Thus, the proposed controlled current source based on a co-operating inductive-capacitive converter and a thyristor controller ensures the resonant stabilization of the load current and its regulation in a wide range even in short circuit mode. Expansion of the control range at low load is achieved by disconnecting it from the energy source simultaneously with shorting the IEP output.

The construction of the source, namely the location of the regulating element in the DC circuit, the proposed thyristor regulator circuit provides an increase in the conversion frequency and a decrease in the circuit’s size and dimensions, while the installed power of the IEP elements is reduced by pomimizatsii its mode of operation. The output ltr also decreases dramatically, since in the well-known source the thyristor switching frequency of the deep regulation mode remains at 1 Hz and less, and in the proposed one - 1 kHz or more (i.e., a difference of about 3 orders of magnitude). Increases

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Claims (2)

1. An adjustable current source containing an inductive-capacitive converter, the input connected to the leads for connecting the mains supply, a matching transformer, the output connected to the input of the rectifier. 0 about a thyristor controller and a filter choke, one output connected to one of the output pins for connecting the load, characterized by the fact that, in order to extend the functionality by increasing the control range and reducing the mass and size, the first torsion controller is connected with the positive output of the rectifier, the second input - with the negative output of the mitel, the first output is connected to another output of the 5th drossel filter, and the second output - to another output output, and the output is inductive-capacitance A converter is connected to the input of a matching transformer. 2. The current source according to claim 1, about t l and five 0 This is because the thyristor regulator includes parallel to serial thyristors, first and second commutating chokes, serial and parallel diodes, a series-connected capacitor and a charge thyristor, and an additional power source, with the anodes of the parallel and serial thyristors combined and connected to one output the first throttle, the other output of which forms the first input of the regulator, is a reverse diode connected between the cathode of the sequential thyristor j forming the first The output of the regulator and the anode of the serial diode, forming the second output of the regulator, the cathode of the serial diode is connected to the cathode of the parallel diode and forms the second input of the regulator, the anode of the parallel diode is connected to the cathode of the parallel thyristor, the free output of the capacitor and one of the outputs of the switching diode, another terminal of which is connected to the positive terminal of the additional power source, the cathode of the charge thyristor is connected to the negative terminal of the additional power source, and the total a compound of the charging anode of the thyristor is connected to the capacitor to the cathode of the thyristor sequentially. 0 five 0 Phi. g