The possibility analysis of power increase efficiency in generating devices for onboard radio-electronic means Текст научной статьи по специальности «Электротехника, электронная техника, информационные технологии»

A. M. Mikheenko, S. S. Abramov, 1.1. Rezvan Siberian State University ofTelecommunications and Computer Science, Russia, Novosibirsk

THE POSSIBILITY ANALYSIS OF POWER INCREASE EFFICIENCY IN GENERATING DEVICES FOR ONBOARD RADIO-ELECTRONIC MEANS

A generalized analysis of a high frequency key generator is conducted. This analysis allows the power indicators estimation of the generator in a wide frequency range, and in scheme parameters.

Keywords: key generator, on-board system, resonance inverter.

In the issues of space development there is an important one of power supply maintenance for independent objects; these objects are intended for long-term presence in orbit or in interplanetary space. One of the working capacity maintenance ways oflong-term space objects is the increase in power efficiency for the basic consumers - onboard electronic systems. This particularly concerns powerful generating devices for communication purposes.

For powerful radio devices the biharmonic mode generator had been widely used. With the advent of powerful solid-state electronics application, duple schemes of consecutive resonant inverters (class generators “D”) [1] came into exploitation.

The possibility of energy conversion efficiency increase withanupset loading, was discoveredby E. P. Khmelnitskiy inthe 1960s [2]. Inforeign sources, generators of suchtype were known as class E generators, as in Russian they were identified as key generators with a forming contour [3]. Despite the fact that class E generators provide high energy conversion efficiency for limited key modes frequencies, in a variety of causes their application is limited, and they are still on the stage of experiment. The scheme analysis for a wide range of frequencies and scheme parameters generally, has a lower result.

A simplified scheme of the generator is presented in figure 1, where AE is the active element (transistor, lamp) working in the key mode; VD is a diode that provides recuperation of energy ofjet elements in an opened key; L, C are the elements of a contour, defining the form of pressure on AE; Lk, Ck are the loading contours, which have been adjusted to the frequency of operating pressure.

0<t<29 2k>t>29

Fig. 1. Scheme ofthe generator

Supposing, that the unlocking and locking of AE is completely defined the by operating pressure (Uk), we will present the investigated generator in two equivalent schemes; they will show the processes happening in the generator in open and closed conditions of the AE. Here uk = U sin (x + +); x = +t; 29 - an angle corresponding to the time during which the AE is open; iL1, iL - currents in the external chain of the generator for corresponding equivalent schemes.

The differential equation for equivalent schemes becomes:

1 di

L +v 2ir =

v2 E

d iL

dx2 rmC dx

v 2sin(x + +) cos(x + +)

mL

),

d 2i,

U„

d x

2 +v il\ =-------- cos(x + +).

mL

(1)

(2)

The solution for these equations can be written down the following way:

i = / + &Sj cos(x + +) -

-&e2 sin(x + +) + /11ep1x + I12ep 2x...,

(3)

i1 = I21 cos v( x - 29) + 1

+I22 sin v(x - 29) - -

& cos(x + +),

v2 -1 U = -&Sj sin(x + +) --&e2 cos(x + +) + PjI11eplx + p2I12ep2x, U1 = vI22 cos v( x- 29) -1

(4)

-vI21 sin v(x- 29) +

v2 -1

& sin(x + +).

(5)

The following designations are accepted here: i = iL ,

mL L di,

= lLl ^

E

L dir,

u, =---------

E d x

A =-

mL

E

1

mrC

1

p2 =— - roots of the characteristic equation (1); /

v2 =-

1

m LC /v4

mL Uk

/ =------, &= —;

r E

pi - (v2 -1) p + (v2 -1)2

“2 2 + ( 2 1)2, In,I\i,I2i,I22 - integrationconstants.

Supposing that the generator mode had been established, we will define the integration constants, using the current continuity principle in inductance and in capacity pressure ofcontourLC:

r

i(0) = i,(2)); i(20) = /1(20), (7)

uc = urf(2-); uc (20) = uc(20) (8)

Here Uc = E - Uk - UL. (9)

Onthe basis of (3)-(6) in conditions (7)-(9) we will receive:

111 = A1 + &(Busin + + Bl2 cos +);

112 = A2 + &( B2j sin + + B22 cos +);

I2j = A3 + &( B3jsin + + B32cos +);

122 = A4 + &( B4j sin + + B42 cos +).

ajb2 - a2bj

ajb2 - a2bj

R = a2b4j - a4jb2.

BJJ =-

Bj2 =

B2j =

1a 2b - a2b1

a2b42 - a42b2

1a 2b - a2b1

. a42b1 - a1b42

1a 2b 1 2 1b

. a41b1 1 1 4b

ajb2 - a2bj

aj = 1 - e2pj0 cos2v(--0) —Le2pj0 sin2v(--0); jg a2 = 1 - e2p20 cos2v(--0) - Pe2p20 sin2v(--0);

a3 =ct[1 -cos2v(--0)];

a41 = -12 + q1 cos2v(--0) + — q2 sin2v(--0);

v

a42 = s2 - q2 cos2v(--0) +1 q1 sin2v(--0);

v

b1 = -p1[1 -e2p10 cos2v(--0) +—e2pl0 sin2v(--0)];

v

b2 = -p2[1 -e2p20 cos2v(--0) +—e2p20 sin2v(--0)];

v

1

S3 =81 +- 2

b3 =- —sin2v(--0); , ,

v v -1

b41 =s2 - q1cos2v()-0) + vq2 sin2v(--0);

A3 = / + A1e2 p10+ A2 e2 p20;

A4 = A1e2 p10+ A2e2 p 20;

v v

B31 = Bne2p10+ B2/p20 - q1;

q1 = (s3 sin20 + 82 cos20);

B32 = B12e2p10+ B22e2p20 - q2;

q2 = (s3 cos20-s2 sin20);

1

For the definition of the generator’s power indicators it is necessary to define the current of the first loading harmonic and the current consumed from the power supply.

I1 =VI2s + I12c = ~ ~ tg+ = ^. (11)

cos + sin + I1s

Here:

(10)

I1s =--

E

1 20 12- H ij sin 4 d4 +------------------H iT1 si

TT J L TT J L1

sin 4 d4 =

' 20 2 -

In the last expressions the following designations are accepted:

A = a2b3 - a3b2 . A = a3b1 - a1b3 .

-mL

( J i sin 4d4 + J i1 sin 4d4) :

E

-nL

[A5 + &( B51 sin + + B52 cos +)];

1 20 12-

I1c = — J iL cos 4 d4+ J iL1 cos 4 d4 =

TT J IT J

E

A + &(B61 sin+ + B62 cos +)].

(12)

(13)

-nL

Parameters A5, A6, B51, B52, B61, B62 are defined by the

following expressions:

1 A

A5 =— [/(1 - cos20) +-------L— d12 +

- 1 + p1

B41 =- (p1 Bne2pM + p2 B^e - q2);

v

B42 =^(p1B12e2p10+ p2B22e2p20 -q1). v

Substituting the values of integration constants (10) in equations (3)-(6), we will receive the description of an inductance current and pressure for the established generator mode.

1

v2 -1

(A3d13 + A4d14 )];

B51 =

1 1 sin 40 cos 40 1

+ ~ [83^—------------------0) +S2(—-------7) +

v2 -1 - 4 4 4

B11 , B21

du +-------------------— d12 +

1

1+p2

1 + p22 12 ' v2 -1

(B31d13 + B41 d14 )];

D 1 sin40 cos40 1

B52 = [S2 ( . 0) S3 ( . . ) +

- 4 4 4

B11 B22

+-------------^ d11 +----------------— d12 +

1

(B32d13 + B42 d14)];

1+pf 11 1+p22 12 v2-1

d11 = 1 - e2p10 (cos20- p1sin20); d12 = 1 - e2 p 20 (cos 20 - p2 sin 20); d13 = cos 2v(- -0) - cos 20; d14 = sin2v(--0) + v sin20;

1 A

A6 =— [/ sin20+-------L— d21 +

- 1 + p1

A 1

+1---2f d22 + ~-1 (A3 d23 + A4 d24 )];

1 + p2 v -1

D 1 cos40 1 sin40

B61 = [s3( . . ) S2( . +0) +

- 4 4 4

'1 2d 21 + 1 2 d22 + 2 1 (B31 d23 + B41d24)];

1 + p1 1 + p2 v-1

1 1 sin 40 /cos 40 1

2 . +-[l2 ( 4 +0) + S3(—-----4) +

v -1 - 4 4 4

B62 = - . 2

B12 -d21 + -BVd22 +-

1

1 , 2 21 ! 2 22 2 1

1 + p1 1 + p2 v-1

(B32 d23 + B42d24)];

d21 = - p1 + e2 p10 (p1 cos 20 + sin 20); d22 = - p2 + e2 p 20 (p2 cos 20 + sin 20); d23 =vsin2v(--0) + sin20; d24 = cos20- cos2v(--0).

+

The electricity consumed from the source:

As a first approximation IpJ

10 = J_J d4 = -IJ

2- '0 r 2- 1

E - Uk - Ul

<d 4 = ■

Ea

2-mL

J ct[1 -&sin(4 + +) - u]d 4 (14)

U is defined by expression (5).

Result of the integration(14):

I0 = EaCT {20 + |[cos(20 + +) - cos +](1 -s1 ) +

2-nL

+&s 2 [sin(20 + +) - sin +] +

+I11(1 - e2p10) +112(1 - e2 p 2 0)}. (15)

The efficiency of the first harmonic is defined by the knownparity [3]

" = 2 5 i.

2 h

As & = ^

EE

. I1A

that agrees & =

cos+

R [A5 +&( B51 sin+ + B52 cos +)]

mL cos +

On the other hand,

tg+ = Li. = A6 +5(B61 sin + + B62 cos +)

I1s A5 +&(B51 sin + + B52 cos +) '

(16)

(12)

(17)

(18)

m0

1

mrC

^2 =

mL

p1 p2 m’~0 4lC'

Inthe frequency characteristics of the generator’s energy conversion efficiency it is possible to receive surface construction planes (figure 2), corresponding to specific

p2

relation values of —; energy conversion efficiency

A

schedules. The function — = — is presented in figure 3.

p2 r

The system of the transcendental equations (17), (18) allows us to define the required value of o.

From the conducted analysis we can see, that direct calculations of the generator’s power indicators are rather labor-consuming, because of the bulky calculations and the impossibility of an analytical solution for this system of equations(17), (18).

Therefore in each separate case it is expedient to resort numerical methods by using computer calculations.

As an example, we have executed the PEVM energy conversion efficiency calculation. The generator for the special case is 0 = 90° and RH = 5r.

Figure 2 shows the generator’s energy conversion efficiency dependence from the frequency and the LC contour parameters on a plane of variables ^?1^2).

Fig. 3. Frequency characteristics of the generator

Here as in figure 2, the special case 0 = 90° and RH =5ris considered.

The conducted analysis states that direct calculations of the generator’s energy features are rather complicated. The reasonforthis is the excessive calculation size andthe analytical impossibility of solving equation systems (17), (18).

It is advisable to use numerical methods together with calculating devices for each case.

In conclusion we can say that it is possible to considerably increase the generator’s energy conversion efficiency; in comparison with standard power converters, the energy conversion efficiency of which does not exceed 40...60% for high frequencies.

Fig. 2. Energy conversionefficiency ofthe generator

Bibliography

1. Dmitrikov, V. F. Highly effective shapers ofharmonious fluctuations/N. B. Petjashin, M. A. Sivers. M., 1988.192 p. (inRussian)

2. Khmelnitskiy, E. P. Work of the lamp generator on the upset contour / E. P. Khmelnitskiy. M., 1962. 109 p. (in Russian)

3. Artym, A. D. Amplifier of classes D and key generators in a radio communication and broadcasting / A. D. Artym. M., 1980. -209 p. (inRussian)

© Mikheenko A. M., Abramov S. S., Rezan 1.1., 2009

Yu. M. Ermoshkin, S. A. Orlov JSC “AcademicianM. F. Reshetnev “Information Satellite Systems”, Russia, Zheleznogorsk

A. Yu. Usanov Experimental DesignBureau “Fakel”, Russia, Kaliningrad

DEVELOPMENT OF MECHANICAL TEST PROCEDURE FOR THE FUEL BELLOWS TANKS

The mechanical qualification and acceptance test requirements are considered for the fuel bellows tanks. Some procedural mistakes taking place during these tests are described.

Keywords: spacecraft, tank, storage and feed unit, mechanical tests, resonance.

For decades the fuel storage/feed units based on the bellows tanks are successfully used in the monopropellant propulsions ofthe domestic spacecrafts (SCs). Inorderto use the fuel storage units for new generation SCs (i. e. to be exposed higher mechanical loads) there was a necessity to perform supplemental mechanical tests to prove their durability.

SC hardware ground test plan includes the acceleration, vibration and shock tests [1; 2]. The tests levels are based on the data obtained from hardware operating conditions analysis, equipment mass and its allocation on the SC.

The storage and feed unit (SFU) manufacturer has to procure off-the shelf tanks from other supplier and then has to equip it with supplemental hardware in order to obtain the SFU as an item of SC propulsion.

During the SFU development testing, bellows of two tanks were corrupted (along an external crimp weld) when they were exposed to mechanical environment. This damage occurred directly along the weld, and not in an area around the weld; it was typically if the weld was well done i. e. this damage designated an insufficient quality of the join. It is necessary to note that such welds in the tanks are critical because they influence the strength of the whole assembly; the thickness of weldment isn’t great, while the total length of weld may be hundreds of meters long. However, all the delivered tanks for the integration of the SFUs have passed the acceptance tests at the manufacturer’s site.

In order to analyze the failures of tank bellows and to generate the levels of durability and acceptance tests, supplemental mechanical tests of two SFUs had been conducted. This work is meant to review all the test results and to identify the possible procedural mistakes that have made it impossible to detect manufacturing flaws during the acceptance tests of tanks.

Test Objectives. During the test campaign it was necessary to achieve a set of mutually complementary objectives:

- to detect the rupture sources of tank bellows;

- to develop a technique for determination of low eigenfrequencies of the bellows located inside a tank;

- to estimateaninfluence of testprocedure onthe test data;

- to confirm or exclude an influence of the test hardware (fixture, tools, control system, etc) to the test results;

- to update the durability/acceptance test levels for tank andSFU.

Test equipment and mechanical loads. The following mechanical tests were performed:

- resonance search within a frequency range of 5 Hz to

2.000 Hz with level of0,5g and a scanning rate of 2 octave/min;

- sine vibration within a frequency range of5Hzto2,000 Hz with levels of1to12g;

- random vibration within a frequency range of20Hz to

2.000 Hz with levels of0.02to0.2 g2/Hz;

- quasi-static loads with levels of ±10g;

- shocks with levels of ±40 g.

The test specifications were generated proceeding from the SFU operation conditions at levels of the SC and in compliance with an approach as described in [3; 4]. They have met the requirements as established in[1;2]. The tests were conducted in few phases changing the levels and duration ofloading. The following equipment was used:

- centrifuge C-400;

- shock testbench ST-800;

- vibration shakerLDS V894/440.

Beforehand, the test equipment and test fixture were subjected to approval. The equipment’s low eigenfrequency is about 1,000 Hz. All the test hardware corresponded to the test standards according to the test specification accuracy and provided the mechanical loading of the SFU and was measured with the following tolerances:

- vibration acceleration amplitude: ±10 %;

- vibration acceleration power spectral density: ±6dB;