SU1658137A1 - Current stabilization device - Google Patents

Description

(/ 11) 4469450/0 /

(22) 07.29.88

(46) 06.23.91. Bul No. 23

(71) Institute of Electrodynamics, Academy of Sciences of Ukraine

(72) I.Volkov, S.I. Zakrevsky, M.N.Gorbachev, Yu.I.Starodumov,

A.AchGolovach and I.S. Chumakov

(53) 612.316.1 (088.8)

(56) Mil x A.N. and others. Systems of constant current based on inductive-capacitive converters. Kiev .: Naukova Dumka, 1974, p. 214.

Abstract of the thesis of VGTurkovsky. Installation of the stabilized current of the power supply system of electrical technology consumers by the non-stationary mode. Minsk, 1984, p. 9.

(54) DEVICE FOR CURRENT STABILIZATION

(57) The invention relates to electrical engineering. The aim of the invention is to reduce power consumption by

current limiting at the input of the converter in idle mode. In normal mode, the device provides parametric stabilization of the current in the circuit with a variable load. In idle mode, chokes with non-linear weber-ampere characteristics are saturated, forming, together with capacitors, parallel circuits tuned to resonance (ferroresonance) currents at the frequency of the supply voltage source. By using the phenomenon of ferroresonance currents in parallel circuits, achieved by appropriately selecting parameters of chokes with non-linear weder ampere characteristics and capacitors of the input circuits of an inductive-capacitive converter, the output voltage and input current in each phase of the device are simultaneously limited. 3 il.

S

(L

The invention relates to electrical engineering.

The purpose of the invention is to reduce the. required power by limiting the current at the converter input at idle.

FIG. 1 shows the block diagram of the claimed device in the most common m-laser version; Figures 2 and 3 are given as examples, respectively, of the T-shaped scheme of a bee-mutually inductive coupling and a bridge circuit as variants of the claimed device,

The proposed device has a supply network 1, an inductive-capacitive converter 2; resistance 3 load Zn, chokes 4 with non-linear weber-ampere characteristics.

The device works as follows.

In normal mode, in each phase of the load 3, a nominal current flows, the effective value of which is stabilized by means of an inductive-capacitive converter 2 connected to an alternating voltage source 1. In this mode, a choke 4 s is not 05

ate

oo

from 1

The linear weber-amimer characteristic is in an unsaturated state and its inductive resistance XLt is much higher than in a saturated state, therefore a rather small current flows in its circuit, which is no more than 5-7% of the load current. In idle mode of the converter due to an open circuit of the load, YEN is loaded only on the choke 4. The voltage at the output of the IEP thus increases, as a result of which the magnetic conductor throttle 4 enters the saturation state and thereby limits the value of the output and the converter at a certain level Ufcj) ix. In idle mode, due to the saturation of the chokes 4, the structure of the input circuits of the converter, made according to any T-phase scheme (Fig. 1), changes from L-shaped to T-shaped without interconnecting connections with a short-closed output . The parameters of the capacitor and the throttles 4 of each phase of the converter are calculated in such a way that the inductive resistance in the saturation state XBHg is tuned to resonance with capacitance C (Input circuit capacitor at the frequency of the supply voltage 11) resonance (ferroresonance) of the currents occurs, as a result of which the input current of the converter reaches the minimum value I in x x at the rated voltage of the mains supply UB) l Cf and at the same time the output is limited voltage of the converter at a given level U, M) (. The value of V c. is determined by the formula

U

Bh.sr

UuJL.Mtiii ± Ufiktta iP 2

Where is ih. m "and ubh. max respectively the minimum and maximum values of the supply voltage. Therefore, in idle mode, the proposed device switches from the output current stabilizer mode to the output voltage stabilizer mode. In this case, the adjustment of the parallel circuits of the converter to the ferro-reanance of the currents is carried out with the help of taps on the winding of the drossel 4 with the non-linear weber-ampere characteristic.

Based on the results of theoretical and experimental studies of the proposed device, its parameters should be chosen from the following relationships:

0

five

0

five

0

five

0

45

50

55

LbM2. lu

. (UlUblJL- - 1) XL2;

Exit and XHG; UlfcЈtY

(ABOUT

(2) (3)

gde ivyh.h.h. and USWX.M. - the output voltage of the converter, respectively, in idle mode and nominal mode, and PVB | XN corresponds to the optimum value of the relative load of the IEP; XL, is the inductive resistance of drossel with a linear weber-ampere characteristic included in each phase of the IEP; 1 „“ - short-circuit current of the converter, determined depending on the value of the rated current I n of the converter according to the ratio 61.15 1 „.

The design expression (1) is valid for chokes with non-linear weber-ampere characteristics made on the cores made of ferromagnetic materials (for example, from ordinary electrical steels used in low and medium power transformers) for which the ratio

XL1., D. XLHj 35 32

established on the basis of experimental studies.

The novelty of the invention lies in the fact that the proposed device for stabilizing the current provides in idle mode a simultaneous limitation (stabilization) of the output voltage and minimization of the current consumed from the network.

The positive effect of using the present invention is to save electrical energy consumed from the network and to increase the efficiency of the converter, achieved due to the minimum value of the input current in the idling mode of the converter.

The use of the invention allows to increase the efficiency of the converter by improving the energy performance in idle mode (power ratio and efficiency); increase the reliability of the converter operation by limiting the voltage in idle mode while reducing the current consumption to the lowest possible value.

Claims (1)

Invention Formula Device for stabilizing current in m-phane load, containing t-phase inductance-capacitive converter with pre-connected inductive element in each phase and hectares of chokes  t 7- -t- FIG. 2 from nonlinear gR0 -; chporprl hllkchgristikika, about t Ji and chu oh so the fact that, in order to reduce power consumption by limiting the current at the input of the converter in idle mode, each of m chokes with non-linear weber-ampere characteristic is connected in parallel to the capacitive element of each of the m phases of the converter, and the inductive resistance of the specified throttle is chosen equal to the reactive resistance of the capacitive element. 1