Congresso del Dipartimento di Fisica
Highlights in Physics 2005
Power Electronics CAD:
from space applications to
industrial applications
P.G. Maranesi, M. Riva
Electronic Section – Department of Physics
University of Milan
Via Celoria 16, 20133 Milano
Italy
Summary
 Space applications often dragged power
electronics in other fields
 Still the aerospace stimulates innovation
 The case of FREDOMSIM for Computer
Aided Analysis and Design of SPS for
satellites is dealt with here:
_ The Global Star example
_ Dynamic Models of ISS DC/DC Converters
 Technical fall-out
Power Electronics CAD: space and industrial applications
2
Dynamic Characterization and
Control Optimization of the
PWM DC-DC Converters
a) Characterization of the Power Cell in the Frequency
Domain
b) Assignment of Inner Feedback and Feed Forward
compensations
c) Assignment of the External Feedback Network
d) Closed Loop Characterization
e) Connection with Other Circuit Blocks and System
Characterization
Power Electronics CAD: space and industrial applications
3
Dynamic Description in the
State Space Discrete Time



x[(k  1)T ]  Ax (kT )  Bu (kT )



y(kT )  Cx (kT )  Du (kT )
Z-transform



zX ( z )  A
 X ( z)  B
 U ( z)
Y ( z )  CX ( z )  DU ( z )


1
Y ( z )  C ( zI  A) B  D U ( z )

z  e jT

H (e jT )  C (e jT I  A)1 B  D
Power Electronics CAD: space and industrial applications


4
Discrete time model
automatic build up
kT
1
x(kT ) 
x( )d
T ( k 1)T
x(t )
x(k  1)T   A  xkT   B  ukT 
y (kT )  C  xkT   D  ukT 
kT
y (t )
AVERAGING
1
y (kT ) 
y ( )d
T ( k 1)T
A, B, C, D Matrices Computation
xi [(k  1)T ]  A  xi kT 
x h k 1T   B  uh kT 
y i kT   C  xi kT 
y h kT   D  uh kT 
Power Electronics CAD: space and industrial applications
5
Dynamic Characterization and
Control Optimization of the
PWM DC-DC Converters
a) Characterization of the Power Cell in the Frequency
Domain
b) Assignment of Inner Feedback and Feed Forward
compensations
c) Assignment of the External Feedback Network
d) Closed Loop Characterization
e) Connection with Other Circuit Blocks and System
Characterization
Power Electronics CAD: space and industrial applications
6
Inner feedback and
feed-forward compensations
xk  1T   A  BFxkT   BI  G   ukT 

ykT   C  DF  xkT   DI  G   ukT 
F inner feedback matrix
G feed-forward matrix


H( z )  C  DFzI  A  BF  B  BG   DI  G 
1
Power Electronics CAD: space and industrial applications
7
Dynamic Characterization and
Control Optimization of the
PWM DC-DC Converters
a) Characterization of the Power Cell in the Frequency
Domain
b) Assignment of Inner Feedback and Feed Forward
compensations
c) Assignment of the External Feedback Network
d) Closed Loop Characterization
e) Connection with Other Circuit Blocks and System
Characterization
Power Electronics CAD: space and industrial applications
8
Power Distribution on the ISS
Power Electronics CAD: space and industrial applications
9
Full Bridge Push-Pull PS
Po
Po,max =
S2
Co
iL
S6
+
S4
T2
Vo
Vin
load
- _T
T1
Llk
-
Vin = n V o
Vin2 T
____
8L
2
S3
S5
- T_
4
T3
0
T
_
4
T
_
2

S1
t 0 t 1 t2 t 3
t4 t 5 t 6 t 7
T/2
t8
T/2
Vin 2 T T
  ( - T )
L T
2
T
T
S3,6 ON
S4,5 ON
S3,6 ON
S1 ON
S2 ON
S1 ON
I L0
P0= 2 
S4,5 ON
S2 ON
During the short delay between the ON-OFF and OFF-ON
commutations, resonant transitions occur involving inductor
L and MOSFET parasitic capacitors.
I L =IT1
0
-I L0
switch commands and the inductor current waveform
Power Electronics CAD: space and industrial applications
10
Full Bridge Phase Shifted
Lo
Vin
S1
iL
S4
Co
Vo
load
Vs
L
R
T1
T2
S2
S3
D3
Power Electronics CAD: space and industrial applications
11
This tool has been used
profitably elsewhere
 Hybrid switching power supplies design
 Large bandwidth HV generators for high
resolution CRTs
 Impedance characterization of inverter
fed induction motors
 Dynamic stability forecasts of power
distribution systems
Power Electronics CAD: space and industrial applications
12
A fall out example:
The distributed power supply system
Intermediate Bus Architecture (IBA)
Card cage
#3
48V
AC
Front
End
Card cage
#2
Card cage
#1
48V
Isolated Bus
Converter
“Intermediate Bus Converter (IBC)”
Or
“Bus Converter (BC)”
Power Electronics CAD: space and industrial applications
Card #2POL
niPOL
Converter
Card #1
niPOL niPOL POL
ConverterConverter
POL
niPOL niPOL POL
niPOL POL
ConverterConverterConverter
POL
Isolated Bus
Converter
12V
Card #3
Isolated Bus
Converter
niPOL niPOL POL
ConverterConverter
niPOL
Converter
POL
POL
13
The converter for the distributed power
supply systems: Switch in Line Converter (SILC)

Suddivisione della tensione in ingresso
 Minori perdite di conduzione
 Minor rapporto spire
 Possibile di utilizzo di trasformatori planari
Power Electronics CAD: space and industrial applications
14
Conclusions
 The development of FDS was stimulated by
space application exigencies
 It provides a fast and accurate description of the
the dynamics and it helps the design
optimization
 It opens up the possibility of worst case
analyses of the dynamic performances
 It can be profitably employed also in industrial
applications
Power Electronics CAD: space and industrial applications
15
Congresso del Dipartimento di Fisica
Highlights in Physics 2005
Power Electronics CAD:
from space applications to
industrial applications
P.G. Maranesi, M. Riva
Electronic Section – Department of Physics
University of Milan
Via Celoria 16, 20133 Milano
Italy