Since 1984, NASA Lewis Research Center was developing high power, high frequency space power components as part of The Space Station Advanced Development program. The purpose of The Advanced Development program was to accelerate existing component programs to ensure their availability for use on the Space Station. These components include a rotary power transfer device, remote power controllers, remote bus isolators, high power semiconductor, a high power semiconductor package, high frequency-high power cable, high frequency-high power connectors, and high frequency-high power transformers. All the components were developed to the prototype level and will be installed in the Lewis Research Center Space Station power system test bed

Renz, David D.

English

NASA Technical Reports Server

NASA Technical Memorandum 100866 
Power Components for the l a 
20-kHz Power Distribution 
(NA S A-TH- 1 008 66 ) POW ER CON PONE NT S 
Space Station 
System 
PO& T H E  N 88- 2 1 374 
SPACE STATION 20-kHz POMEB D I S T B I B U T I G N  
SYS7.!l3# (NASA) 10 p csiz 0C)c 
Unclas 
G 3 / 3  1 0 140265 
David D. Rem 
Lewis Research Center 
Clevelund, Ohio 
Prepared for the 
23rd Intersociety Energy Conversion Engineering Conference 
cosponsored by the ASME, AIAA, ANS, SAE, IEEE, ACS, and AIChE 
Denver, Colorado, July 31-August 5, 1988 
https://ntrs.nasa.gov/search.jsp?R=19880011990 2020-03-20T06:26:42+00:00Z
POWER COMPONENTS FOR THE SPACE STATION 20-kHZ POWER DISTRIBUTION SYSTEM 
D a v i d  D. Renz 
N a t i o n a l  A e r o n a u t i c s  and Space A d m i n i s t r a t i o n  
L e w i s  Research  C e n t e r  
C l e v e l a n d ,  O h i o  44135 
ABSTRACT 
S i n c e  1984, NASA L e w i s  Research  C e n t e r  has  been 
d e v e l o p i n g  h i g h  power ,  h i g h  f r e q u e n c y  space power  com- 
p o n e n t s  as  p a r t  of The Space S t a t i o n  Advanced Deve lop -  
ment p r o g r a m .  The p u r p o s e  o f  The Advanced Deve lopmen t  
N p r o g r a m  was to  a c c e l e r a t e  e x i s t i n g  component p rog rams  
o t o  e n s u r e  t h e i r  a v a i l a b i l i t y  f o r  use on t h e  Space S t a -  
I t i o n .  These components  i n c l u d e  a r o t a r y  power t r a n s -  
f e r  d e v i c e ,  remote  power  c o n t r o l l e r s ,  r e m o t e  bus  
i s o l a t o r s ,  h i g h  power  s e m i c o n d u c t o r ,  a h i g h  power  semi-  
c o n d u c t o r  package ,  h i g h  f r e q u e n c y - h i g h  power  c a b l e ,  
h i g h  f r e q u e n c y - h i g h  power  c o n n e c t o r s ,  and  h i g h  
f r e q u e n c y - h i g h  pcwer  t r a n s f o r m e r s .  A l l  t h e  components  
have been d e v e l o p e d  t o  t h e  p r o t o t y p e  l e v e l  and  w i l l  
be i n s t a l l e d  i n  t h e  NASA L e w i s  Space S t a t i o n  power 
sys tem t e s t  b e d .  
OI 
Ft 
LL: 
INTRODUCTION 
I n  t h e  l a t e  s i x t i e s  and  e a r l y  s e v e n t i e s  i t  became 
a p p a r e n t  t h a t  t h e  power  r e q u i r e m e n t s  o f  f u t u r e  space-  
c r a f t  w o u l d  r i s e  from t h e  p r e s e n t  k i l o w a t t  l e v e l  t o  
t h e  hundreds  o f  k i l o w a t t  l e v e l  b y  t h e  y e a r  2000. The 
i n i t i a l  space s t a t i o n  w h i c h  i s  p l a n n e d  f o r  t h e  m i d d l e  
n i n e t i e s  has a p r o j e c t e d  power  l e v e l  o f  7 5  kW w i t h  a 
g r o w t h  p o t e n t i a l  o f  300 kW. 
A low v o l t a g e  dc  d i s t r i b u t i o n  s y s t e m  w i l l  not  be 
s u i t a b l e  due t o  t h e  l a r g e  c o n d u c t o r  w e i g h t  r e q u i r e d  t o  
c a r r y  t h e  c u r r e n t s .  An o b v i o u s  so lu t ion  to  r e d u c i n g  
c o n d u c t o r  w e i g h t  i s  t o  r a i s e  t h e  o p e r a t i n g  v o l t a g e .  
A n o t h e r  way t o  r e d u c e  w e i g h t  i s  t o  use a h i g h  f r e -  
quency  a t  sys tem w h i c h  d e c r e a s e s  b o t h  w e i g h t  and  s i z e  
o f  m a g n e t i c  d e v i c e s  such  as  t r a n s f o r m e r s .  
A t  t h e  b e g i n i i n g  o f  t h e  Space S t a t i o n  P rog ram,  
NASA p e r f o r m e d  an e x t e n s i v e  power  s y s t e m  t r a d e  s t u d y  
c o m p a r i n g  150 V dc ,  440  V-400 H z ,  and 440 V-20 kHz .  
The c o n c l u s i o n  o f  t h i s  t r a d e  s t u d y  was t h a t  t h e  
440 V-20 kHz power s y s t e m  was t h e  mos t  e f f i c i e n t ,  
l i g h t e s t ,  and l o w e s t  i n - c o s t .  The s t u d y  a l s o  showed 
t h a t  t h e  440 V-20 kHz power  s y s t e m  h a d  no t e c h n i c a l  
show s t o p p e r s  b u t  t h a t  t h e  20 kHz component t e c h n o l o g y  
was n o t  as  f u l l y  d e v e l o p e d  as  t h a t  o f  t h e  o t h e r  power  
s y s  terns. 
NASA L e w i s  has been d e v e l o p i n g  power  components  
for  some t i m e  t h a t  t a k e  a d v a n t a g e  o f  b o t h  h i g h  v o l t -  
age and h i g h  f r e q u e n c y  ( 1 ) .  The Space S t a t i o n  
Advanced Deve lopmen t  p r o g r a m  augmented t h e s e  e x i s t i n g  
p rog rams  and s t a r t e d  new ones  on a n  a c c e l e r a t e d  sched-  
u l e  t o  e n s u r e  t h a t  t h e  components  w o u l d  be a v a i l a b l e  
f o r  use  i n  t h e  Space S t a t i o n  Power Sys tem.  The o b j e c -  
t i v e  o f  t h i s  p a p e r  i s  t o  summar ize  t h e  Space S t a t i o n  
Advanced Deve lopmen t  P rog ram for  space power compo- 
n e n t s  and p r o v i d e  a comprehens ive  r e p o r t .  
ROTARY POWER TRANSFER DEVICE 
I n  t h e  e a r l y  e i g h t i e s ,  S p e r r y  F l i g h t  Sys tems deve-  
l o p e d  f o r  NASA Lew is  a m u l t i h u n d r e d  k i l o w a t t  Rol l  R i n g  
assemb ly  ( 2 ) .  The Rol l  R i n g  i s  a d e v i c e  t h a t  t r a n s -  
f e r s  e l e c t r i c a l  power  a c r o s s  a r o t a t i n g  j o i n t  through 
r o t a t i n g  f l e x u r e s  compressed be tween  c o n c e n t r i c  con-  
d u c t o r s  ( F i g .  1 ) .  The a d v a n t a g e s  o f  t h e  Ro l l  R i n g  
o v e r  t h e  s l i p  r i n g  a r e  t h e  e l i m i n a t i o n  o f  s l i d i n g  
f r i c t i o n  and t h e  low t o r q u e  needed t o  r o t a t e  t h e  
d e v i c e .  The Ro l l  R i n g  c a n  t r a n s f e r  b o t h  a c  and d c  
power  and has  a measured e f f i c i e n c y  o f  0 .9998  ( 3 ) .  
There  a r e  e i g h t  c i r c u i t s  i n  t h e  assemb ly  ( F i g .  2 )  
each  c a p a b l e  of c o n d u c t i n g  200  A a t  500 V d c .  T h i s  
Ro l l  R i n g  assemb ly  won a 1985 IR-100 award  f o r  one  of 
t h e  b e s t  new p r o d u c t s  o f  t h a t  y e a r .  
A second Rol l  R i n g  assemb ly  was b u i l t  for NASA 
L e w i s  w i t h  f o u r  c i r c u i t s  ( t h e  f i r s t  a s s e m b l y  h a d  e i g h t  
c i r c u i t s )  ( F i g .  3 ) .  The Space S t a t i o n  Advanced D e v e l -  
opment p r o g r a m  r e d e s i g n e d  t h e  4 - c i r c u i t  Roll R i n g  
assemb ly  a f t e r  e v a l u a t i o n  t e s t i n g  (3) t o  d e c r e a s e  t h e  
o u t g a s s i n g  t i m e  o f  t h e  assemb ly  and  t o  e l i m i n a t e  pos -  
s i b l e  c o r o n a  p r o b l e m s .  P r e s e n t l y ,  t h e  Ro l l  R i n g  i s  
b a s e l i n e d  as  t h e  Space S t a t i o n  a l p h a - j o i n t  power 
t r a n s f e r  d e v i c e .  The four c i r c u i t  Roll R i n g  assemb ly  
i s  s t i l l  u n d e r  g o i n g  440 V-20 kHz vacuum t e s t i n g  a t  
NASA L e w i s  ( F i g .  4 ) .  The Rol l  R i n g  assemb ly  i s  c o r o n a  
checked  e v e r y  f e w  months  d u r i n g  t h e  vacuum l i f e  t e s t .  
B o t h  a s s e m b l i e s  have a c c u m u l a t e d  i n  excess  o f  60 
Space S t a t i o n  y e a r s  of r o l l i n g  t i m e  ( 8 - c i r c u i t  Ro l l  
R i n g  assemb ly  - 6 4  y e a r s ,  4 - c i r c u i t  Roll R i n g  assemb ly  
- 114 y e a r )  a t  100 A or g r e a t e r  ( 3 ) .  Thus f a r  t h e  
Ro l l  R i n g  a s s e m b l i e s  have  met  or  exceeded a l l  s p e c i f i -  
c a t i o n s  o f  t h e  o r i g i n a l  c o n t r a c t .  
ONGINAD PAGE IS 
OF POOR QUALITY 
HIGH POWER SEMICONDUCTOR 
General Electric Company is presently under con- 
tract with NASA Lewis to produce a high voltage MCT 
(Mos Controlled Thyristor) (4). The MCT under devel- 
opment for NASA Lewis is a 1200 V,  40 A device with a 
switching time of one microsecond and forward drop of 
1 v. 
turn-off. 
thyristor, and MCT representative schematics (5). 
The MCT is planned to be used on the Space Station in 
remote power controllers, main inverters, frequency 
changers, charge/di;cnarge converters and motor con- 
trollers. The MCT with a 1000 V to 40 A rating will 
be commercially avaiiable in the fall of 1988. 
The MCT also requires low gate drive power for 
Figure 5 shows the transistor equivalent, 
allow for system failure analysis. Figure 10 shows a 
100-A RBI without a control card. 
HIGH POWER SEMICONDUCTCR PACKAGE 
Power Technology Components developed a high power 
semiconductor package for NASA Lewis (6). This pack- 
age has low inductance due to the lead configuration 
and electrically isoidtes the power chip from the 
case. The package I ;  hermetically sealed and has an 
internal coating of pdrylene (Union Carbide Corp. 
Trademark) which provides voltage breakdown protec- 
tion in case the hermetic seal fails (Figs. 6 and 7 ) .  
The MCT chip will be mounted in this package and 
then tested in the various Space Station test bed cir- 
cuits. Power Technology Components has a commercial 
version without the parylene coating marketed as their 
"power mode" series. 
REMOTE POWER CONTROLLERS AND REMOTE BUS ISOLATERS 
Leach Corporation i s  developing for NASA Lewis a 
family o f  208 V rms - 20 kHz remote power controllers 
(RPC's) (5, 10, 25 A) and a family of 440 V rms - 
20 kHz remote bus isolators (RBI's) (25, 50, 100 A) 
( 7 ) .  The RPC's are current limiting switches that 
isolate the power distribution system from load faults 
( 8 ) .  If a load faults, the RPC switches in a current 
limiting reactance within 2 ps, limits the fault to 
300 percent of the RPC rating and removes the load at 
the end of this first half cycle of operation (25 psec) 
The RPC's will accept on and off commands and current 
trip point commands. The RPC will supply to the data 
system the status (on or off), load current, load volt- 
age, sign o f  the volt-ampere product and the last cur- 
rent reading before tripping. This last current read- 
ing will allow time for system failure analysis while 
protecting the system from overload. The Leach RPC 
uses parallel FET's for the switching function and has 
a metal contact relay in series for dead heading the 
switch. Figure 8 shows an 8-A FET power hybrid module 
and Fig. 9 shows a 25-A RPC which mounts four hybrid 
modules on the control card. In the next generation 
design the Mos Controlled Thyristor (MCT) will replace 
the FET's. 
The remote bus isolators (RBI's) are metal contac- 
tors that are used for power bus reconfiguration ( 7 ) .  
Under normal operating conditions, they will not be 
switched under load. Testing at NASA Lewis has shown 
that they may be switched when current is flowing but 
this is not desirable. The RBI's will only accept on 
and off commands. The RBI's will supply to the data 
system the status (on/off), bus current, bus voltage, 
sign of the volt-ampere product and the last current 
reading when power is removed from the bus. This last 
current reading plus the volt-ampere product will 
POWER CABLE AND CONNECTORS 
In 1980, Induction General, Inc. developed for 
NASA a high power, low inductance, 20 kHz cable (9). 
The main reason for the low inductance was to reduce 
the external magnetic field of the cable, it also 
improved the cable voltage drop and minimized the cross 
ralk between the loads. The cable was constructed as 
a double sided strip line using straps made o f  Lit2 
wire (Fig. 1 1 ) .  The Litz wire cable was designed to 
deliver 25 kW with a 2 percent real loss over 50 m .  
The Induction General cable parameters were: resist- 
ance: 0 . 8 3  m - Q / m ,  inductance: 0.035 micro-H/m, 
capacitance: 0.00137 micro-F/m, and weight: 1 kg/m. 
onstrate that a low inductance cable was possible. 
The Litz wire cable showed some problems, such as: 
very long out gassing times due to gasses trapped in 
the Litz wire, holding cable configuration constant 
during the manufacturing process (caused field induct- 
ance to increase), not very flexible and fairly heavy. 
A second generation cable is being made for NASA Lewis 
by W.L. Gore and Associates, Inc. (10). This cable 
design uses solid flat foil conductors instead of the 
Litz wire braid. The foil conductors also were covered 
with a solid dielectric coating and outgassing will be 
achieved by using a gas permable dielectric for a filler 
and outer jacket material. This cable will have 
approximately the same electrical parameters as the 
Li tz cable, better uniformity duriog the manufacturing 
process, but will weigh less and have greater flexi- 
bility (Fig. 1 1 ) .  
440 V - 20 kHz - 30 kVA connector for terminating the 
20 kHz flat foil cable being developed by GORE (11). 
The connector being designed for NASA Lewis has a 
voltage drop of 0.375 V at rated current (68 A) and 
will weigh approximately 1 lb. It is also being de- 
signed for handling with space suit type gloves (Fig. 
12). 
The Induction General cable was developed to dem- 
G&H Technology, Inc. is developing for NASA a 
TRANSFORMERS 
TRW is developing for NASA Lewis a 440/220, 2 0  kHz, 
25 kVA transformer (12). The wiring schematic of this 
transformer is shown in Fig. 13. The measured leakage 
inductance is 1.6 micro-H, which exceeds the specifi- 
cation limit o f  3 . 0  micro-H. The measured efficiency 
of 99.36 percent exceeds the design goal of 98 percent 
and the unit weighs approximately 10 lbs. unpotted 
(Fig. 14). Figure 14 shows the unpotted transformer 
along with one seven turn secondary. This transformer 
will be installed in the NASA Lewis Space Station 
power system test bed for evaluation and system tests. 
REFERENCES 
I .  Renz. D . D . ,  1984, "High Voltage - High Power 
Components for Large Space Power Distribution 
Sys terns ,"  NASA TM-83648. 
2. Jacobson, P.E., 1985, "Multi-Hundred Kilowatt 
Rol 1 Ring Assembly," NASA CR-174832. 
3. Renz, D.D., 1988, "Multi-Hundred Kilowatt Roll 
Ring Evaluation Results," NASA TM-100865. 
ORIGINAL PAGE IS 
OF POOR QILTALITY 
2 
4 .  Renz, D . D . ,  Project Manager, 1988, "Development 
o f  Fas t  S w i t c h i n g  - H igh  Power Semiconductors , "  
General  E l e c t r i c  Co.,  Schenectady, NY,  NASA 
C o n t r a c t  NAS3-24898. 
5. TemDle. V . A . K . .  1987. "MOS C o n t r o l l e d  T h y r i s t o r s  
i n  Energy Convers ion  Systems," Enerqy - New 
F r o n t i e r s  (22nd IECEC). A I A A ,  New York.  
6. B a l o d i s ,  V . ,  Berman, A . ,  Devance, D . .  Ludlow, G . .  
and Wagner, L . ,  1987, "Space S t a t i o n  Power S e m i -  
conductor  Package," NASA CR-180829. 
7 .  Renz, D.D.,  Project  Manager, "Remote Power Con- 
t r o l l e r  and Bus I s o l a t e r , "  Leach C o r p o r a t i o n ,  
NASA C o n t r a c t  NAS3-24660. 
8 .  T o f i q h .  F., 1987. "208VAC. 20 kHz H y b r l d  Remote 
Powet C o n t r o l l e r  , "  Energy - New F r o n t i e r s  (22nd 
I E C E C ) ,  A I A A .  New York .  
9 .  1986, "H igh  Frequency Power D i s t r i b u t i o n  System." 
NASA CR-175071. 
10. Renz, D.D., P r o j e c t  Manager, 1988, "H igh  Power 
Connector Development,  Task 5,'' TRW Space 
Technology Labs, NASA C o n t r a c t  NAS3-24667. 
1 1 .  Renz, D . D . ,  P r o j e c t  Manager, 1988, "H igh  Power 
Connector Development, Task 7," TRW Space 
Technology Labs, NASA C o n t r a c t  NAS3-24667. 
o f  20 kHz - 2 5  kVA Trans former  for  Space S t a t i o n ,  
Task 4 , "  TRW Space Technology Labs, NASA C o n t r a c t  
12.  Gourash, F., P r o j e c t  Manager, 1988, "Development 
NAS3-24667. 
FIGURE 1. - SINGLE ROLL RING CIRCUIT. 
3 
r OUTPUT TERM1 NAL 
I 
FIGURE 2. - CROSS SECTION OF THE 8 - C I R C U I T  ROLL R I N G  
EVALUATION U N I T .  
INNER ,? OUTER 
a, BARRIERS CONDUCTOR R I N G  7, I CONDUCTOR ' R I N G  I 
INPUT , 1 
TERN I NAL 
CD-84-14533  
I 
I- OUTPUT 
TERN I NAL 
F IGURE 3. - FOUR C I R C U I T  ROLL R I N G  ASSEMBLY, 
4 'ORIGINAL PAGE IS 
OB POOR QU-ALITY 
A 
FIGURE 4. - FOUR C I R C U I T  ROLL RING ASSEMBLY IN VACUUM TESl 
bC 
TRANSISTOR 
EQUIVALENT 
FIGURE 5 .  
d 
C 
THYR I STOR 
REPRESENTATIVE SEMICONDUCTOR 
f A 
C 
NOS CONTROLLER 
THYR I STOR 
SCHEMATICS . 
5 
FIGURE 6. - POWER SEMICONDUCTOR PACKAGE 
FIGURE 8. - FET POWER HYBRID ( 8  AMP) M0I)ULE. 
J 
FIGURE 7 .  - HERMETIC. HIGH POWER SEMICONDUCTOR PACKAGE. 
C-88-03392 
FIGURE 9. - 25 AMP REMOTE POWER CONTROLLER. 
4 4 0 V  - l O O A  - 
I “ - --m 
FIGURE 10. - 100 AMP REMOTE BUS ISOLATOR (NO CONTROL CARD). 
F I G U R E  11. - TWO 20 KHZ CABLE C O N F I G U R A T I O N S .  
7 
F I G U R E  12. - 20 KHZ BUS CONNECTOR. 
CORE 
20 KHz 
FIGURE 13. - 440/220, 25 KVA TRANSFORMER SCHEMATIC. 
FIGURE 14. - 25 KFA-20 KILOHURTZ TRANSFORMER. 
8 ORIGINAL PAGE IS 
OE POOR QUALITY 
Nalmnal ASA Aeronautics and Report Documentation Page 
Space Admlntslral~on 
1. Report No. 
NASA TM-100866 
2. Government Accession No. 
7. Author@) 
D a v i d  D .  Renz 
7. Key Words (Suggested by Author@)) 
Space power components; Vacuum power 
components; Power d i s t r i b u t i o n  
components; H i g h  f requency  components 
9. Performing Organization Name and Address 
N a t i o n a l  A e r o n a u t i c s  and Space A d m i n i s t r a t i o n  
Lewis  Research Cen te r  
C l e v e l a n d ,  O h i o  44135-3191 
18. Distribution Statement 
U n c l a s s i f i e d  - U n l i m i t e d  
S u b j e c t  Ca tegory  31 
~~~ ~~ 
12. Sponsoring Agency Name and Address 
9. Security Classif. (of this report) 
Unc 1 ass i f i e d  
N a t i o n a l  A e r o n a u t i c s  and Space A d m i n i s t r a t i o n  
Washington,  D . C .  20546-0001 
21. No of pages 22. Price' 20. Security Classif. (of this page) 
U n c l a s s i f i e d  10 A02 
15. Supplementary Notes 
3. Recipient's Catalog No. 
5. Report Date 
6. Performing Organization Code 
8. Performing Organization Report No. 
E-4092 
10. Work Unit No. 
481 -54-32 
11. Contract or Grant No. 
13. Type of Report and Period Covered 
T e c h n i c a l  Memorandum 
14. Sponsoring Agency Code 
Prepared f o r  t h e  2 3 r d  I n t e r s o c i e t y  Energy Convers ion  E n g i n e e r i n g  Conference 
cosponsored by  t h e  ASME, A I A A ,  ANS, SAE,  I E E E ,  ACS, and AIChE, Denver ,  Co lo rado ,  
J u l y  31 - August  5 ,  1988. 
16. Abstract 
S i n c e  1984, NASA Lewis  Research Cen te r  has been d e v e l o p i n g  h i g h  power,  h i g h  f r e -  
quency space power components as p a r t  o f  The Space S t a t i o n  Advanced Development  
program. 
e x i s t i n g  component programs t o  ensure  t h e i r  a v a i l a b i l i t y  for use on  t h e  Space 
S t a t i o n .  These components i n c l u d e  a r o t a r y  power t r a n s f e r  d e v i c e ,  remote  power 
c o n t r o l l e r s ,  remote  bus i s o l a t o r s ,  h i g h  power semiconduc to r ,  a h i g h  power semi- 
c o n d u c t o r  package,  h i g h  f requency -h igh  power c a b l e ,  h i g h  f r e q u e n c y - h i g h  power 
c o n n e c t o r s ,  and h i g h  f r e q u e n c y - h i g h  power t r a n s f o r m e r s .  A l l  t h e  components have 
been deve loped  t o  t h e  p r o t o t y p e  l e v e l  and w i l l  be i n s t a l l e d  i n  t h e  Lewis  Research 
Cen te r  Space S t a t i o n  power system t e s t  bed.  
The purpose o f  The Advanced Development p rogram was t o  a c c e l e r a t e  


Power components for the space station 20-kHz power distribution system

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