CC BY
16
Section 11. Technical science
Bobojanov Maksud Kalandarovich, Tashkent State Technical University, Power faculty, Department of Power Supply, Professor, Usmanov Eldar Ganievich, Tashkent State Technical University, Power faculty, Department of Electric Power Supply, Associate Professor
Abduraimov Erkin Hamidovich, Tashkent State Technical University, Power faculty, Department of Electrical Engineering, Associate Professor Karimov Rakhmatillo Chorievich, Tashkent state technical university, Power faculty, "Power supply" chair, senior teacher, E-mail: raxmatillo82@mail.ru
RESISTIVE TIME DELAY SWITCHES
Abstract: Transient processes with the solution of differential equations of state by the numerical method of the proposed non-contact high-speed time relay.
Keywords: optocoupler, photodiode, diode, resistance, capacitor, thyristor, time relay.
At present, due to the extensive automation of pro- nusoidal current passes through zero, which provides an
duction processes, the introduction of automatic con- improvement in the mode of the transient process [1]. trol systems, the requirements to reliability, speed, and Sometimes with circuit solutions, such as relay pro-
longevity of electrical appliances and apparatus have sig- tection and automation, parallel operation of thyristors,
nificantly increased. These requirements are largely met etc. it is necessary to delay the control pulses in time.
by devices based on the use of properties and phenom- Therefore, the creation of small-sized, high-speed, non-
ena inherent in nonlinear resistive circuits. In the future, contact time relays is relevant.
a significant expansion of the scope of applications of This article discusses the creation of such relays
nonlinear circuits is expected as instruments and appa- based on resistive circuits. When creating and develop-
ratus with new qualitative properties. At present, semi- ing new technology, there are questions of calculation
conductor circuits are generally used as power switches and analysis of such circuits. Non-autonomous nonlin-
for switching, regulating and converting devices. On the ear dynamic circuits with a diode, active resistance and
basis of theoretical analysis and experimental research of capacitance are widely used. When developing control
nonlinear resistive circuits, it is established that to pro- systems for automation devices, various circuit solutions
vide high-quality power supply to consumers it is neces- can be used [2].
sary to use such circuits as power contactless switching Let's perform a theoretical analysis ofthe circuit shown devices. The circuits on the basis of non-linear resistive in (Fig. 1), where the active resistance (R1), the diode (VD) circuits make it possible to switch the power loads un- and capacitance (C) are connected in series, the active reder the best dynamic conditions, namely, when the si- sistor (R2) and the photodiode of the optocoupler (VU).
RESISTIVE TIME DELAY SWITCHES
Figure 1.
To analyze this chain, we propose to use the numerical solution of the equation of state of the chain [3].
Let us consider the transient processes during the periods of the open state of the diode VD, the voltage across the capacitance is described by the following equation:
R ( -R^t}
, R. .R_ .C (l)
Uc = u n
R + R
1 - g R1 R2 c
here, Um - rated mains voltage.
At present, various methods of analyzing such chains are widely used. We propose to use the numerical solution of the chain state equations by the Euler method. In this case, on an interval, it is necessary to determine an approximate solution of equation:
di = f(t,y) (2)
We take the characteristic of the diode to be ideal and assume that u = U Sinwt. Then, from the moment t = 0
m 1
to t, the diode is open, and the equation of the circuit has the following form:
U sin at = R
CdUc + Uc_ dt R
+ Ur
2 7
or
dU
1
U m sin at -Ur
R
1 + R
R
'2
dt R1C where, UC - capacitance voltage.
The solution of Euler's equation (3) is as follows:
(3)
UC (k+1) = UCk + f (UCk ,tk ) •h
Here
f (Uck ,tk ) =
R1C
Um sin at - Ur
R
1 + R1
R
2 J
(4)
(5)
k=0, 1, 2, ..., n.; h - step of integration.
From the moment t = 0 to t = t, the voltage on the capacitance is determined by (4) with zero initial condition. From the moment t = t, the diode switches to the closed state and the voltage at the capacitance is determined as:
CdUc
U
dU
U
or
dt R2 dt CR2
(6)
From the moment t = t, the diode again switches to an open state and the voltage on the capacitance is again described by the dependence (4), only with the initial conditions corresponding to the time t = t.
(Fig. 2. a), shows the characteristics of the function Uc = f(t). These characteristics are constructed for different values of the resistance R1. Moreover, R2 and C remain constant. Curve 1 at R2 = 3000 O; 2 - R2 = 2000 O; 3 - R2 = 1000 O; 4 - R2 = 500 O; 5 - R2 = 250 O; C = 10 ^F and R1 = 300 O.
(Fig. 2. b), shows the characteristics of the dependence Uc = f(t). These characteristics are constructed for different resistances R2. In this case, R1 and C remain constant. Curve 1 with R = 300 O; 2 - R1 = 500 O; 3 - R1=800 O; 4 - R1=1000O; 5 - R1=1200 il; C=10 ^F and ^2=3000 O.
(Fig. 2. c), shows the characteristics of the dependence Uc=f(t). These characteristics are constructed for different values of the resistance R1. Moreover, C and R2 remain constant. Curve 1 at C = 10 pF; 2 - C = 20 pF; 3 -C = 30 pF; 4 - C = 40 pF; R1 = 1200 O and R2 = 3000 O.
From these dependences it is evident that by changing the parameters of the circuit it is possible to regulate the time of full charging of the capacitor.
The proposed contactless relay was investigated in the laboratory of the Energy Department of the Tashkent State Technical University [2, 3].
It can be seen from (Fig. 2) that the change in the parameter R2 has almost no effect on the charging time of the capacitor C, and the variation of the parameters R1 and C significantly changes the charging time of the capacitor, hence the operating time of the optocoupler.
Based on the above, you can draw the following conclusions:
Using the circuit shown in (Fig. 1), it is possible to create a contactless, high-speed and time relay, changing the parameters of the active resistance R1 or capacitance C.
In conclusion, it can also be noted that the analysis of the dynamic circuit shown in (Fig. 1), where the active
resistance, diode and capacitance are connected in series, connected in parallel to the capacitance, can be performed and the resistor and photodiode of the optocoupler are by numerical solution of the chain state equations.
80
60
40
20
Ue (B)
2 __ l3
1
^4
/Г t(сек)
80
60
40
20
и, (В)
1
/
/А- й5 4
If t (сек)
10 15
a)
b)
80 60
40 20
0
Figure 2. Shows the voltage versus capacity curves versus time for various parameters of the circuit elements
The proposed technique makes it possible to pro- transient processes of chains with various parameter duce a qualitative analysis of steady-state regimes and variations [4].
References:
1. Усманов Э. Г., Абдураимов Э. Х., Каримов Р. Ч. Нелинейная динамическая цепь с тиристором // Журнал «Проблемы информатики и энергетики».- Ташкент,- 2006.- № 2-3.- С. 37-41.
2. Rasulov A. N., Karimov R. Ch. Operating mode of the stabilizer of current on active and inductive loading // Scientific journal «European Science review» Austria, Vienna,- 2015.- No. 9-10. September-October.-P. 140-143.
3. Karimov R. Ch., Karimov I. Ch. Research of diode resistive chains in power supply systems // Scientific journal "Young scientist USA". Auburn, Washington,- 2016.- No. 5.- P. 106-109. URL: http://www.YoungScientistUSA. com
4. Rasulov A. N., Karimov R. Ch. The Contactless Relay of Tension in System of Power Supply // Scientific journal "Eastern European". Germany, Dusseldorf,- 2015.- No. 4. Ausgabe.- P. 174-178. URL: http://www.Auris-Verlag.de
