This is a set of working notes – hopefully useful to illustrate the tests that have been made, but...
51
This is a set of working notes – hopefully useful to illustrate the tests that have been made, but not intended as a real “presentation”. • MPOD special parallel unit, ch 0/1/2 used here • At first, according to “original” cable plan, test setup used 120 feet 12AWG cable (Belden #5000FE) • 3x 150uF (T495D157K010ATE100) at load (at first – changed later, see below) • Load is Agilent 6060B • Sense connected with 107 feet Belden #9503 (3x 24AWG twisted pair w/ overall foil shield, one pair used here) • Direct connect to sense terminals at PS (try other setups maybe too?) • Setpoint 2.70V (I’m not sure of 6060B performance much lower than this, and this is I hope close enough to our lowest setpoint in system, 2.16V) • “PWM offset” control set to 12.5V except as noted • With all that, following pages show (at remote load / sense connection) the transient response LV DC Power Supply Tests at Indiana Universi
This is a set of working notes – hopefully useful to illustrate the tests that have been made, but not intended as a real “presentation”. MPOD special
This is a set of working notes hopefully useful to illustrate
the tests that have been made, but not intended as a real
presentation. MPOD special parallel unit, ch 0/1/2 used here At
first, according to original cable plan, test setup used 120 feet
12AWG cable (Belden #5000FE) 3x 150uF (T495D157K010ATE100) at load
(at first changed later, see below) Load is Agilent 6060B Sense
connected with 107 feet Belden #9503 (3x 24AWG twisted pair w/
overall foil shield, one pair used here) Direct connect to sense
terminals at PS (try other setups maybe too?) Setpoint 2.70V (Im
not sure of 6060B performance much lower than this, and this is I
hope close enough to our lowest setpoint in system, 2.16V) PWM
offset control set to 12.5V except as noted With all that,
following pages show (at remote load / sense connection) the
transient response with various 3A load steps (10 Hz square wave),
from 6060B. iTOP LV DC Power Supply Tests at Indiana
University
Slide 2
2A to 5A PWM offset: 12.5V
Slide 3
5A to 2A PWM offset: 12.5V
Slide 4
8A to 11A PWM offset: 12.5V
Slide 5
11A to 8A PWM offset: 12.5V
Slide 6
8A to 11A PWM offset: 12.5V (ref1), 8.0V (ch1)
Slide 7
11A to 8A PWM offset: 12.5V (ref1), 8.0V (ch1)
Slide 8
At this point, switched to 106 ft Belden # 5T00UP (10AWG,
unshielded). This better approximates the revised and hopefully
final cable design: 4C 10AWG 2C 16AWG (perhaps to 14AWG) 3pair
24AWG overall foil shield maximum length is expected to be 106ft
(32.2m) according to measurements made at Belle-II 1/2015 For the
test, sense line connected as before. Lack of shielding on test
power lines is not likely to make a significant difference.
Slide 9
8A to 11A PWM offset: 12.5V
Slide 10
11A to 8A PWM offset: 12.5V
Slide 11
8A to 11A PWM offset: 12.5Vno cap at load
Slide 12
11A to 8A PWM offset: 12.5Vno cap at load
Slide 13
8A to 11A PWM offset: 12.5Vgeneric 1mF 63V aluminum axial
Slide 14
11A to 8A PWM offset: 12.5Vgeneric 1mF 63V aluminum axial
Slide 15
The large aluminum capacitor stabilizes it, but I think cannot
really be used due to lifetime/reliability concerns. We have to use
tantalum, or probably better now the niobium oxide capacitors which
have a benign open-circuit failure mode. Next pages explore this.
Some damping resistor seems to be necessary, but thats fine.
Now basically lets assume that this load capacitance is what
well use. I looked into aluminum caps a bit, but reliability looks
to be worse even for the long-life grades. And, although only one
part instead of 8-10 are needed, it isnt actually smaller. The
niobium oxide caps look like the best option for us. So (for now)
we use 3x NOJD107M010RWB || ((7x NOJD107M010RWB) + 60m)
Slide 26
5A to 2A (ref1) & 4A to 1A (ch1) PWM offset: 12.5V Results
seem consistent w/ ~2.5mF total output capacitance (ours + MPOD
internal)
Slide 27
1A to 4A (ref1), 2A to 5A (ref2), 3A to 6A (ref3), 4A to 7A
(ref4), 5A to 8A (ch1) PWM offset: 12.5V
Slide 28
6A to 9A (ref1), 7A to 10A (ref2), 8A to 11A (ref3), 9A to 12A
(ref4), 10A to 13A (ch1) PWM offset: 12.5V
Slide 29
10A to 13A (ref1), 11A to 14A (ref2), 11.5A to 14.5A (ch1) PWM
offset: 12.5V
Slide 30
PWM_offset=12.5V, no PWM from Umod (ref1), PWM_offset=12.5V,
yes PWM from Umod (ch1) 11A to 14A
Slide 31
PWM_offset=12.5V, no PWM from Umod (ref1), PWM_offset=6V, no
PWM from Umod (ch1) 11A to 14A
Slide 32
PWM_offset=12.5V, no PWM from Umod (ref1), PWM_offset=6V, yes
PWM from Umod (ch1) 11A to 14A
Slide 33
PWM_offset=12.5V, no PWM from Umod (ref1), PWM_offset=15V, no
PWM from Umod (ch1) 11A to 14A
Slide 34
PWM_offset=12.5V, no PWM from Umod (ref1), PWM_offset=15V, yes
PWM from Umod (ch1) 11A to 14A
Slide 35
PWM_offset= 15V (ref1), 13V (ref2), 11V (ref3), 9V (ref4), 7V
(ch1) 11A to 14Aall cases no PWM from Umod
Slide 36
PWM_offset= 7V (ref1) as before, 6V (ref2), 5V (ref3), 4V (ch1)
11A to 14Aall cases no PWM from Umod
Slide 37
MUSEcontrol screenshots, in steady-state operation (maybe not
fully warmed up, but close) with 14.5A load (nominal from 6060B
front panel entry / readout)
Slide 38
I plan to check still the waveforms at PS terminals under the
various 3A transient steps quick comparison of performance at 5V
regulated instead of 2.7V any difference in stability efficiency
check (although it isnt very meaningful with so little overall load
on the crate, we can probably still get some useful info from it,
by looking at AC input delta with load 0A, 14.5A) cable temperature
measurement (qualitative impression is, it is much cooler than the
12AWG cable) And then I have to return the MPOD mainframe to
Wiener. Next testing will be by them, with PL512. If that looks
good, we should buy one for our prototype.
1A to 4A (ref1), 2A to 5A (ref2), 3A to 6A (ref3), 4A to 7A
(ref4), 5A to 8A (ch1) PWM offset: 12.5V PS terminal voltage scope
offset adjusted to overlay traces, same V/div
Slide 41
PWM offset: 12.5V PS terminal voltage scope offset adjusted to
overlay traces, same V/div 6A to 9A (ref1), 7A to 10A (ref2), 8A to
11A (ref3), 9A to 12A (ref4), 10A to 13A (ch1)
Slide 42
PWM offset: 12.5V PS terminal voltage scope offset adjusted to
overlay traces, same V/div 10A to 13A (ref1), 11A to 14A (ref2),
11.5A to 14.5A (ch1)
Slide 43
PWM offset: 12.5V 11A to 14A PS terminal voltage scope offset
adjusted to overlay traces, same V/div Vset=2.7V (ref1), Vset=3.7V
(ref2), Vset=4.7V (ch1)
Slide 44
PWM offset: 12.5V 6.4A to 9.4A PS terminal voltage scope offset
adjusted to overlay traces, same V/div Vset=13.85V (ref1),
Vset=13.35V (ch1) ref1 scale is offset +500mV This was a check that
we can run right up to the voltage limit of the supply and still
hold regulation. Success. Unfortunately, scope offset range
limitations get in the way here. But that isnt important.
Slide 45
PWM offset: 12.5V 6.4A to 9.4A PS terminal voltage scope offset
adjusted to overlay traces, same V/div Vset=13.85V (ref1),
Vset=15.00V (ch1) ref1 on same scale (no offset) In fact, we can go
beyond the nameplate 16V limit. MUSEcontrol allows max terminal
voltage to be set to 17.6V, did that, we can run right up to it and
it works well as seen here.
Slide 46
3A to 4A (ref1), 3A to 5A (ref2), 3A to 6A (ref3), 3A to 7A
(ref4), 3A to 8A (ch1) PWM offset: 12.5V
Slide 47
3A to 3.2A (ref1), 3A to 3.4A (ref2), 3A to 3.6A (ref3), 3A to
3.8A (ref4), 3A to 4A (ch1) PWM offset: 12.5V
Slide 48
Now a look at if we can do any better using fast remote sense
setting (i.e. medium box unchecked in MUSEcontrol) together with
some external network to stabilize. First revisited the load
capacitance, I find can get just as good, maybe slightly better,
performance from 60m+(10x NOJD107M010RWB). So thats whats there
now. Also, find that sense input to MPOD is pretty high impedance,
and we can connect sense lines with up to few hundred Ohms and have
no change in performance. (Tested at MPOD, not at load side, need
to re- check.) Fast regulation stabilized with 450 to load sense
cable, 400 nF to PS out terminal, on each PS sense terminal (i.e.
one of these networks on positive and one on negative). This was
done with substitution boxes and values optimized by a bit of
experimentation. But performance that way is not as good as medium
regulation mode with no network (or with only 50 resistors and no
caps), see next slide. Thats fine, medium regulation mode looks
good for us. This was just a test to see what happens; note that we
use a similar network to make long distance remote sense work on
Excelsys unit under test.
Slide 49
medium (ref1), fast w/ 450 , 400nF (ch1) PWM offset: 12.5V 3A
to 6A
Slide 50
I confirmed, the 50 or even up to a few hundred Ohm resistors
can be used to connect the sense lines at the load. I think we will
probably do this rather than use polyfuses. Resistors should be
more reliable and convenient. Final circuit (showing only one of
the three PS circuits that feed each FEE (boardstack) is below:
Note that (owing to space constraints) the final 1.2m of the
circuit is run on lighter gauge wire and remote sense is placed at
the junction point not at the FEE.
Slide 51
Question: We may be able to use 8V modules (and so 2 ch
parallel for 20A capability, rather than 3 ch parallel for 15A). On
the 16V unit, max terminal voltage is 17.6V according to
MUSEcontrol. It doesnt seem to be specified on the datasheet. From
my testing, this really works Is the exact value universal, or it
depends on specific modules calibration? What is guaranteed minimum
value of this, if it varies. And most importantly, what is
corresponding value for the 8V 10A MPOD module????