CC BY
0_ISSN2077-1738. 36ipnuK nayxoeux npaifb ffonffTY. 2014. № 2 (43)_
_E^ektpqtexhika. Pa^iqtexhika_
UDC.62-83:612.313
Candidate of Engineering Sciences Dryuchin V.G., Candidate of Engineering Sciences Samcheliev Yu.P.,
Belokha G.S., Bakaev O. V.
(DonSTU, Alchevsk, Ukraine)
POWER SUPPLY WITH DISCRETE ELECTRICITY CONSUMPTION
We propose a discrete power supply with power consumption and relay—controlled electromagneti-cally compatible with the circuit, which is invariant to the action of the perturbation and reduced losses in the power supply line. The analytical expressions to calculate the frequency relay modes, power losses and simulation results are given.
Key words: electromagnetic compatibility, relay control, invariance, power loss, power supply
At the present time the solution of electromagnetic compatibility and energy saving problem is at the first place during the development of any converters of electric energy parameters. The most effective means of integrated solutions of this problem (inactive component of the total compensation of power and the power distortion) are the power active filters (PAF) with Pulse Width or vector control. Algorithms implementing these controls are based on a large amount of measurement, conversion and computing operations, which lead to complication control system and deterrence of their introduction [1].
Another way to solve the EMC problem is proposed in this article: using tracker system with forced formation circuit consumed currents close to sinusoidal shape in the absence of a phase shift between voltage and current (the problem of EMC is solved) and relay control (the problem of speed, accuracy, low sensitivity of the perturbation to the action is solved). Such a solution can dramatically simplify both power section and control system [2].
At the expense of power factor close to unit, a reduction of the quantity current consumed by the circuit and hence reduction of the power loss in the supply lines is reached.
The proposed control power supply algorithm allows additionally reducing the power
loss in the line due to the discrete electricity consumption of the circuit.
Figure 1 shows a functional block diagram of the power supply, made on the basis of a single-phase module (SPM).
Figure 1 — Functional diagram of the power supply
The module consists of two keys K1 and K2 with bilateral conductive, input throttle L , current sensor UA, two IGBT transistors shunted by bypass diodes, two capacitors C1 and C2 and the voltage sensor UVC on the capacitors.
The control system consists of coefficient
*
unit (CU) of capacitor voltages U ^12 and current consumption of the circuit i = Im sin œt, two adders, two relay elements RE1 and RE2
E.tektpotexhika. Pa^iotexhika
where i is the current increase time from
* *
(i - a) to (i + a), 12 is current reduction
**
time from (i + a) to (i - a).
and logic device (LD) providing work of the keys K1, K2 and transistors VT1, VT2.
Before working it is necessary the capacitors C1 and C2 to be charged to a voltage exceeding the peak value of the phase voltage (it is a necessary condition of the module efficiency) UC1 = Uc2 > Um . When applied to a summing input of the first adder the signal i = Im sin ra t, and the countdown input from the UA voltage output sensor, the unit impulse or zero signal, depending on the sign of
the error Ai = i* - i unit appears on the output Figure 2 — Determination of the time11 and 12
element of the relay RE1.
The transistors VT1 and VT2 are connected to the capacitors C1 and C2 according to the phase voltage or counter, keeping current in the current corridor, which is set by the width of the hysteresis loop relay element RE1.
The equations describing the behavior of the current in the load, depending on the magnitude and sign of the error is of the form (we neglect throttle active resistance)
r di TT
L--h ud = Um sin rat + U
dt
di
- a < Ai < a,— > 0 dt
di
(1)
+ ud = Um sin rat - UC2
dt
di
- a < Aj < a, — < 0, dt
where Um sin rat is the instantaneous voltage circuit, i is the instantaneous current in the load, L is throttle inductivity, 2a is hysteresis width relay element RE1, ud — the instantaneous load voltage.
The current fragment formation consumed by the circuit is shown in Figure 2, according to which the expressions describing the behavior of the current have the form
2a . di
j = I sin rat h--1 - a < Aj < a,— > 0
' dt
t ■ 2a . . di
i = Im sin rat H--1 - a < Ai < a,— < 0.
t. dt
(2)
In general, the active load comprises an active resistance Rd , inductivity Ld and capacitance Cd . Then the voltage on the load will be
ud = uR + uL + uC ,
(3)
where ur is the voltage on Rd, uL is the voltage on Ld, uC is the voltage on Cd . Taking into consideration (2) the voltage
is determined
uR = ImRd sin rat
di
(4)
By - a < Ai < a, — > 0 dt
ul = raLdIm cos rat +
2aLd .
5
t1
(5)
1 r* 1 f2a , .
uc =--Im cos rat +—J— tdt + A ; (6)
raCd C t1 di
By - a < Ai < a,— < 0 dt
*
Ul = raLdIm cos rat -
t2
2aL
d
(7)
1 r* 1 ,2a , .
uc =--Im cos rat--J— tdt + A ; (8)
raCd C t2
1 f2^ ^ 1 ,2a , -J—tdt « 0 , -J—tdt « 0 . (9)
Cd t1 Cd t2
E.tektpotexhika. paaiotexhika
Since switching keys K1 and K2 is carried out by rat = 0 and rat = n, so from (6) and (8) with (9), the constant of integration is
1 *
A =-Im npu rat = 0
raCd 1*
A =--Im npu rat = n
raCH
(10)
Solving (1), subject to (2-10) with respect to i and i2, we obtain
I1 =
2a( L + Ld )
I2 =
1 *
U - U2 + UC1 ±-— Im raCH
2a( L + Ld )
(11)
- U - U2) + Uc 2 ±— Im raCd
where U1 = (Um - ImRd) sin ra t
U9 =
ra(L + Ld) -
1
raCd
Im cos rat
discharging from the voltage(Uc12 + b) to
*
(Uc12 - b), then processes are repeated .
When the capacitors are being charged the energy balance equation has the form
tt T* T*2 R
(umm - ^d )t =
2
2
C12 ffTT* , z.\2 fTT* z.\2^
(13)
2
-((UC12 + by - (UC12 - by),
where t1 is time to increase the voltage on
C C
the capacitors, C12 = —1 2 , 2b - hysteresis
C1 + C2
width relay element PE2,
*
UC12 = UC1 + UC 2.
We determine the time from (13)
t1 =
4bC12Ucl2 _2bC12Ucl2. (14)
TJ T * - T*2 R
umm Am ^d
P - Pd
d
Then the frequency of the relay mode in
*
the formation of the current i
UC + (U1 - U2)2 ±-— Im
v1 =-raC^~ . (12)
1 4a( L + Ld) V '
The stable operation of the source will be subject to the power balance, i.e. equality of power consumption of the network and load power. Control of the balance of power conservation is carried out by controlling the keys K1 and K2.
If the power consumed from the circuit
U I*
Pc = —mm (the key K1 is closed) is more
than the power of the load, the capacitors C1 and C2 are charged from the voltage
(UJ12 - b)to (UJ12 + b) (Fig. 3). Upon
*
reaching the voltage values (UC12 + b) key K1 opens and K2 closes and capacitors start
The energy balance equation at the capacitor voltage reduction stage will be
*2
Tm Rd ¥ _C12sstt* 7^2
2 /2 =-f((UC2 - * - (15)
- (U*12 + i)2),
where t2 voltage reducing time. We determine 12 from (15)
t = 4bC12UC12 = 2bCnU*C12 (16)
t2 =-I*-n-=-^- . (16)
*2 Tm Rd
Pd
d
We determine the frequency shift keys K1 and K2 as
1 _ Pd (P - Pd )
V 2 =
t1 +12 2bC12Uc12 P
(17)
Relative duration of the power source is in the circuit will be
y =
*2
_ t1 _TmRd =Pd (18)
t1 +12 T T P
1 2 ^ mm
The expression (18) allows to determine the range of current control at a given rated
E.tektpotexhika. Pa^iotexhika
load resistance and the range of variation of the load resistance at a given current.
0 < I * < Um
RH
o < Rd < Um
i*
Rd = const
Im = const
(19)
The control algorithm keys K1 and K2 allows to reduce power loss input line in accordance to
ÁP =
y2 m Ri
(20)
Figure 3 shows the processes in the power source in the current source. Figure 3 a shows the response of the source to the reduction of the current task. Sinusoidal current and cur-
rent coincidences in the phase with the circuit voltage are saved and electromagnetic compatibility is not broken. Figure 3b shows the response of the source to the reduction of the supply voltage. The load current is not changed, i.e. source is not sensitive to the effects of such perturbations, sinusoidal current and cos^ = 1 are saved.
Figure 4 shows the process when the load is fed through inductive capacitive transducer (P switch in position 2). Figure 4a -shows the response source to the reduction to the voltage, figure 4b shows the response to the reduction in the supply voltage. As in the case of a current source, electromagnetic compatibility is not broken, the source is not sensitive to changes in voltage.
III
y VyÁ^v^/ ................ ...... -,.......„.....X, , , 1
1 ! 1 1 r
a)
b)
Figure 3 shows the processes in the power supply in the current source a) reaction to the change in the current job, b) response to changes in voltage
t,s
ISSN 2077-1738. Збгрник наукових праць ДонДТУ. 2014. № 2 (43)
Електротехшка. Радютехшка
a)
40
uxlö,b
i,A o
20
40 200 »d,B 100
0
100
"20(!ü 0.1 0.2 0.3 0.4 0.5 0.6 t,S 0.7
b)
Figure 4 shows the processes in the power source voltage source mode a) response to changes in voltage reference, b) response to changes in circuit voltage
Thus, the proposed source of supply is the turbances at power loss reduction in the sup-electromagnetic compatibility with the net- ply line. work, an invariant to the action on it of dis-Bibliography
1. Rozanov Yu. K. Modern methods of control power quality by means of power electronics / Yu. K. Rozanov, M.V. Pyabchitsky, A.A. Kvasnyuk// Electrical Engineering. 1999. — N 4. — P. 36-38.
2. Patent 63521, MPKN02M 7/12. Single-phase current source /Samcheliev Yu. P., Dryuchin V.G., Shevchenko I.S., Belokha G.S.; applicant and the patentee Donbas State Technical University. — N 201103401; is applied 22.03.2011; published 10.10.2011, bulletin N19.
Recommendet to printing by Candidate of Engineering Sciences DonSTU Paaerand YU. E.,
Doctor of Engineering Sciences DSTU Sadovoy A. V.
Received on 16.06.14.
к.т.н. Дрючин В. Г., Самчелеев Ю. П., Белоха Г. С., Бакаев О. В.
(ДонГТУ, г. Алчевск, Украина)
ИСТОЧНИК ПИТАНИЯ С ДИСКРЕТНЫМ ПОТРЕБЛЕНИЕМ ЭЛЕКТРОЭНЕРГИИ
Предложен источник питания с дискретным потреблением электроэнергии и релейным
_ISSN 2077-1738. Збгрник наукових праць ДонДТУ. 2014. № 2 (43)_
_Електротехшка. Радютехшка_
управлением, электромагнитно совместимый с сетью, инвариантный к действию возмущений и с уменьшенными потерями мощности в подводящей линии. Приведены аналитические выражения для расчета частот релейных режимов, потерь мощности и результаты моделирования.
Ключевые слова: электромагнитная совместимость, релейное управление, инвариантность, потери мощности, источник питания.
к.т.н. Дрючин В. Г., Самчелеев Ю. П., Белоха Г. С., Бакаев О. В.
(ДонДТУ, м. Алчевськ, Украгна)
джерело живлення з дискретним споживанням електроенергп
Запропоновано джерело живлення з дискретним споживанням електроенергИ та релейним керуванням, електромагнтно сум1сне з мережею, Швар1антне до дИ збурень i з зменшеними втратами потужностi в лШг тдведення. Наведено аналтичш висловлювання для розрахунку частот релейнихрежимiв i втрат потужностi тарезультати моделювання.
Ключовi слова: електромагнтна сумiснiсть, релейне керування, iнварiантнiсть, втрати потужностi, джерело живлення.
