SU873230A1 - Voltage source to current source lc converter - Google Patents

Description

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The invention relates to electrical engineering and is intended to supply loads with a constant current.

An inductive-capacitive voltage source-to-current source converter is known, which contains a choke and a capacitor battery with equal reactance at the supply frequency, for which each choke is nonlinear {11, for the load phase.

A disadvantage of this device is that due to the presence of droplets with a ferromagnetic core in the resonant circuit with a wide voltage variation, the resonance in the circuit is disturbed, and it cannot be used to supply loads with a wide variation of resistance.

Also known is an inductive-capacitive transducer containing a choke and a capacitor battery with equal magnitude reactors and resistances at the frequency of the supply voltage system, one terminals of which are connected to the first terminals of the load circuit in a star, and the second terminals of the droplets, capacitor battery and the load circuit are connected to pins for connecting to a three-phase supply voltage system, and an additional choke, one output of which is connected to a common point of star 21.

The disadvantage of this device is low reliability due to idle overvoltages.

The purpose of the invention is to increase the reliability of the device.

. For this, the additional choke is made non-linear, and its second end is connected to the zero point of the feed system.

With a single-phase load, the second pins of the additional droplet are connected to the neutral of the power supply voltage supply system.

At a three-phase load, the second. Ends of the additional chokes are connected in a star-

FIG. 1 shows a converter circuit for a single-phase load-r-y in FIG. 2 - vector voltage diagram on converter elements; in fig. 3 - converter for three-phase power supply, option; in fig. 4 - experimental volt-ampere characteristic.

Claims (3)

The inductive-capacitive converter of the voltage source into the current source of the IEP consists of a power matching transformer Tr and reactive elements — droplets L: and a capacitor bank C. The latter is connected to a star, one beam of which is the primary winding of the phase of the power transformer Tr, the second beam, which is lagging behind the first one in phase, is the choke L and is the capacitor bank, the reactance of which is equal to the reactance of the choke. An additional choke is connected to the common point of the star and the neutral of the feeding system. FIG. Figure 2 shows a vector diagram, where Pr,,, -, respectively, of the voltage across the transformer Tr, of the capacitor battery C and the inductor L at the nominal operating mode; , co-i LO-f, respectively, the voltage on the transformer Tr, the capacitor battery C and the choke L at idle mode without an additional throttle DR Ihm Uco, itzo- respectively, the voltage on the transformer Tr, the capacitor battery C .and the choke L at idle mode with additional throttle dr. As is well known, the load current of such a device 1c does not depend on the load resistance Cr1iH (UA / XJ, where n is the transformation ratio of the power transformer; Cd is the power supply voltage; X is the reactance of the capacitor battery (equal to the resistance of the Drossel). The inductive-capacitive converter gives the properties of the current source and provides stabilization of the load current when the load resistance value changes. However, when the source goes to idle mode at Rj ooieo retically 0, and accordingly Voltage across all elements of the installation. Practically with the presence of a matching transformer, the iron of the transformer core is already filled when Uj 1.2its (Fig. 2), the load becomes purely inductive and, as shown in the vector diagram (Fig. 2), the voltage the capacitor battery is about 2.6 times larger, and 1.6 times on the choke. Compatible but for the operation of a known device designed for nominal mode, in idle mode, the installed capacitor battery C must be increased 6.75 times , but Drossel L 2.5 times. To limit the increase in voltage on the elements of the device, between the supply mains neutral t (Fig. 1 and the artificial zero of the inductive-capacitive converter, an additional choke, dr with an iron core, is turned on. The iron of the core of the throttle is not so saturated, the resistance the throttle is large, and the current / passing through it is small, as a result of which, at nominal operating mode, the additional throttle dr consumes little energy. During the rest of the stroke, the voltage at the additional choke increases and its iron is saturated. At the same time, the matching transformer Tr, the capacitor battery C and the choke L are set accordingly to the voltage g / ULO-I (Fig. 2). The installed power of the additional chokes is Dr , 12 PH, while the installed power of the main reactive elements is reduced - capacitor battery C 1, 66 times and choke L 2.1 times. When powering three-phase load, inductive-capacitive converters of each phase IEP 1, IEP 2, IEP 3 are connected to the network by circular movement of phases, and their artificial zero 01, 02 and 03 are connected to the windings of the additional cores with an iron core Dr connected to each other a star. The load R is connected to the matching transformer Tr through the rectifying unit D1-D6. From the experimental volt-ampere characteristic of the device (Fig. 4), it is clear that this device has an almost rectangular characteristic and with an increase in the load resistance since the beginning of saturation of the iron core of the additional drop, the voltage on the load does not increase. Accordingly, the voltages on the reactive elements of the inductive-capacitive converter do not increase. In those cases when the application of known devices with limited no-load voltages is possible (when supplying loads with rapidly changing resistances - plasma arc, electric arc, etc.), the proposed device. gives a large economic effect due to significant decreases in installed capacity of reactive elements. Claim 1. Inductive-capacitive source converter - voltage to current source, containing for each phase of the load choke and capacitor battery with equal magnitude reactance at the frequency of the supply voltage system, some of which are connected to the first terminals of the load circuit, the star, and the second conclusions drossel. a capacitor bank and a load circuit are connected to terminals for connecting to a three-phase supply voltage system, and an additional choke, one pin of which is connected to a common star point, characterized in that, in order to increase the reliability of operation, said additional choke is made nonlinear and its The second terminal is connected to a point with a potential equal to the zero potential of the supply voltage system. 2, The converter according to claim 1, wherein, under single-phase load, the second terminals additional throttle connected to the output of the neutral supply voltage system. 3. The converter according to claim 1, characterized in that, at a three-phase load, the second terminals of the additional chokes are connected to the Star, Sources of information taken into account in the examination 1. Authors certificate of the USSR 479746, cl. G 05. F 3/06, 1970. 2. Mil x A.I. , Volkov I.V. Systems of constant current based on inductive-capacitive converters. K., Naukova Dumka, s, 14E146 (prototype). Ar 01 eoj V "OCCM CEHC pz  u - ja C1 Sh M.,. M Kb Kb M-tt -rt -w FI.5 five F7 / U / ;. 40 go woo hooo fue.