CC BY
37
Section 13. Technical sciences
Section 13. Technical sciences
Rasulov Abdulkhay Norkhadzhayevich, Tashkent state technical university, Power faculty, «Power supply» chair, associate professor
Karimov Rakhmatillo Choriyevich, Tashkent state technical university, Power faculty, «Power supply» chair, senior teacher E-mail: [email protected]
Operating mode of the stabilizer of current on active and inductive loading
Abstract: the scheme of the three-phase stabilizer of current allowing to receive the three-phase stabilized current in loading irrespective of change in the set limits of resistance of loading and the power supply is investigated.
Keywords: magnet, ferroresonance, tiristor, current stabilizer, volt-ampere characteristic, active and inductive loading, linear inductance, Larionov’s scheme, semiconductor rectifier.
The majority of branches of electrical equipment, electrophysics, electrothermie, galvanotechnics, needs automatic maintenance constancy of current at simultaneous change of tension of three-phase food and the consumer’s resistance [1].
Such tasks successfully decides with application magnetic, the ferrorezonansnykh and thyristor stabilizers of current. I have these devices difficult electric circuits and a form of a curve of the stabilized current of not sinusoidal. A form of a curve of the stabilized current use filters of the highest harmonicas to improvement.
In Power supply chair Tashkent State Technical University inductance-capacitor devices with a ferrorezonansny contour which possess property to stabilize current to loading
at broad change of three-phase entrance tension and resistance of loading are developed.
In this work the three-phase scheme of the ferrorezonansny stabilizer of current having a sinusoidal form of a curve of the stabilized current is theoretically and experimentally investigated.
In fig.1. the schematic diagram of the offered three-phase ferrorezonansny stabilizer of the current consisting from three parallel ferrorezonansny contours included linear inductance and the condenser which is switched on in parallel to this contour and collected according to the scheme of a triangle is shown, and tops of this triangle is connected to a three-phase network through active and inductive loading.
Fig. 1. Equivalent circuit of the three-phase ferrorezonansny stabilizer of current
140
Operating mode of the stabilizer of current on active and inductive loading
The analysis of volt-ampere characteristics of separate sites of a chain showed that the parallel ferrorezonansny contour included consistently with linear inductance has “S” — the figurative characteristic with a wide zone of negative site [2].
As showed experimental supervision, linear currents of i1, i2, i3 remain stable in the wide range of change of entrance tension and resistance of loading when the negative site of “S” - the figurative characteristic of a ferrorezonansny branch is compensated by the rectilinear characteristic of C , C23 and C condensers.
Three-phase loading is connected consistently to the current stabilizer.
For the analysis of the load mode we accept the following assumptions:
1. The dynamic curve of magnetization of a ferromagnetic element is approximated by a power function of a look iw = кФ7 [3];
2. Losses on a hysteresis, vortex currents and active resistance are considered by constant conductivity ofg;
3. Streams of dispersion are neglected and streams in linear elements aren’t considered.
We enter the following designations:
- U = Um sm(at + yu) — impressed voltage;
- L1 = L2 = L3 = L — the linear inductance which is consistently connected to a parallel ferrorezonansny contour;
- Cj = С2 = С 3 = С — the condenser which is switched on in parallel to a ferromagnetic element;
- C12 = C23 = C31 = C' — the condenser which is switched on in parallel to a ferrorezonansny contour, switched on consistently with linear inductance;
- iC31; iC12; iC13 — currents proceeding through C condensers; C23 and C12;
- i12; i31; i23 — the currents proceeding at triangle tops;
- ij; i2; i3 — linear currents corresponding in phases 1, 2, 3;
- ig i = ig2 = ig 3 = ig — the current proceeding through conductivity of g;
- ф = 2 з = 1ф — the current proceeding on a
winding of a ferromagnetic element;
- Ф, = Ф2 = Ф3 = Ф — magnetic flux in the core of a ferromagnetic element;
- w1 = w2 = w3 = w — number of rounds of windings of a ferromagnetic element.
The electric chain of the considered three-phase ferrorezonansny stabilizer of current for active and inductive loading is described by the following equations:
—Ф diT, di di-.
U12 = -Фw + L-L + R + LH-±-i2RH -LH-j-,
dt dt dt dt
U23 = ^ w2 + L2 ^ + i2RH + LH - i3RH - LH-3,
23 dt 2 2 dt 2 H H dt 3 H Hdt
dФ.
di
di.
di.
U 31 w 3 + + l3RH + Lh^7 - 11RH - Lh ~7T,
dt 3 3 dt 3 H H dt
i1 = i12 — i13 ; i2 = i23 — i12 ; i3 = i31 — i23 .
dt
Here,
(1)
(2)
(3)
(4)
1 = Cl + lg + 1ф
^ dФ . d^ . К , 7
C = CiwThT; h = gw~d7; гФ = —Ф dt dt w
(5)
(1)- (3) we will solve the equations by method of the accounting of the main harmonica of a magnetic flux [3]. Let’s say that:
Ф = Фт sin at. (6)
When,
U12 = Um sin( tt>f + yu),
U23 = Um sin(at + yu -1200), >
U31 = Um sin(at + ^u +1200).
(35 21 7 1
Ф = Фт -I — sin at----sin3at +---sin5at-----sin7at
\ 64 64 64 64
(7)
(8)
Considering (6)- (8) entering basic sizes after reduction (l) to a dimensionless look we will receive:
У1п = [3Xm • X -1) • (м-р) - 3wXm -sxm • (n-£)]2 +
+ |X • Xm - 1 + S) + 3<5Xm • (»-P) - (9)
- 3nXm • Xm - 1) + 3£Xm • X - 1) - 3^ ]2 ;
Wu =
Xm-(K -1 + $) + 3SXm - (м-р)-3ЛХт -(X6m -1) + 3£Xm ■ (Xj -1)-3y£Xm 3Xm • (Xj -1) -(M-P) - 3МГXm - SXm - 3SXj ■ (n-E)
(10)
The currents proceeding on contours:
^ dФ2 K _7 dФl ^ d2Ф,
hi = Ciwi~rr + — Ф1+ wig 1-ГТ + Cnwi—7T + dt Wi dt dt
d4Ф d3Ф C„ Ф1(Ф, )7
+LiCiwCn -1 + LigwCn -ф + IK-12 • -Ф-dt dt Wi dt
^ ^ dAФ1 T ^ d3Ф^ _ dФ
i23 = L2C2w2C23 —+ L2g2w2C23 _ , + C23w2
dt4
L2KC23 d2(Ф27)
---------------2
w2 dt
dt3
dt2
2 2 dt2
dФ dФ2 K _7
w 2 g+— Ф?;
dt w2
(11)
(12)
131 — L3C 3^^ 3^>13
d4<&* T . d^3
L3g3W зС^—^ +
dt4
dt3
+C w d2Фз , L3KC31 d2(Ф73) +C 3,w3 1
+C,w,
dt2 d 2Ф3 ~dtr
-w 3g 3-
dt2 dФ K
dt w 3
----Ф7.
(13)
Input basic sizes after reduction (11) to a dimensionless look were received:
141
Section 13. Technical sciences
Z =
-22pxm ■ (Xsm -1)+33Xm (Xsm -1) - 22X J3sxm • (i - в)
3SXm . (1 -в) -^ Xm • Xm - 1) +^3 PXm ■ Xm - 1) + ^ УХЯ
2
-|2
+
(14)
^ • (1 -в) X3 Xm . (XSm - 1) X3 PXm ■ Xm ~ 1) X3 YXm t8¥- = 3---------------ъ---------Я-----------------; (15)
-2PXm ■ Xm - 1) + 3Xm ' Xm ~ 1) - ^ ^^ ■ (1 - P)
where,
„ 1 , g , 164 w 2w2C TT T „ 3,
I = T ; Ф5= 6 _ ; 0,= LCwa Ф5;
Ьа>1,мСФя C
aC'
35X
У = —; в= RHaC ’; P = -H; n = LHa'C'; £-~ C ml, L
H_
mL'
For the basic size Ф5 the value of a stream corresponding to a resonant point of a ferrorezonansny contour is accepted. From (9), having set by various Xm values, it is easy to construct the У = f (X ).
m J v m'
On the basis of dependences (9), (10), (14) and (15) we will construct the main characteristics of a chain in relative units for various values of active and inductive loading at change of entrance tension and resistance of loading. From the analysis of the received curves it is visible that currents of ix, i2 and i in a wide limit of change of tension of a network remain stable.
In fig. 2. are submitted:
• theoretical (1 — it1 at ,RH = 20 Ohms, LH = 0.12 Hz) and
• experimental (2 — i(1 at ,RH = 20 Ohms, LH = 0.12 Hz) adjusting characteristics.
The studied skilled stabilizer of current having the following parameters:
• С = С2 = C3 = 40(mkF);
• Lx = L2=L3 = 0.32 (Hz);
• g = 1.21*103 (1/Ohm);
• К=6400*108;
• С12 = С23 = С31 = 20 (mkF);
• f= 0.32 (Hz);
• % = 0.88;
• S=0.88;
• Us = 380 (V);
• Is = 2.3(A).
Introduction to the scheme at the exit of the device of the coordinating transformer and semiconductor rectifiers connected according to Larionov’s (fig. 3) scheme allows to receive the stable straightened current at the exit. Three-phase the ferrorezonansny stabilizer of current with rectifiers can be used for receiving stable current for galvanic electrolysis shops.
In the presence of the alternating current main three-phase the ferrorezonansny stabilizer of current with rectifiers it can be used for receiving stable current for charging of batteries charging stations.
In such devices tension necessary for charging will be automatically established, depending on requirement, without installation of special control devices.
Thus, three-phase the ferrorezonansny stabilizer of current it is possible to consider as tension source converter in a current source, not containing moving parts and contacts working beyond all bounds long. These the device can be built practically on any current.
Fig. 2. Adjusting characteristics of TFST for one phase: 1 — the theoretical; 2 — the experimental
142
Operating mode of the stabilizer of current on active and inductive loading
Fig. 3. Scheme of connection of the vypryamitelny bridge to three-phase device of stabilization of current
References:
1. Milyakh A. N., Volkov I. V. Systems of invariable current on the basis of inductance-capacitor converters. - Kiev: Naukova thought, 1974.
2. Kadyrov T. M., Rasulov A. N. The Ferrorezonansny stabilizer of current with a sinusoidal form of a curve of current. -Automatic equipment and telemechanics, 1977. - № 11.
3. Bessonov L. A. Nonlinear electric chains. - M.: The higher school, 1964.
4. Milyakh A. N., Shidlovsky A. K., Kuznetsov V. G. Schemes of balancing of single-phase loadings in three-phase chains. -Kiev: Naukova thought, 1973.
143
