Puls QS20.241 Power Supply Guia De Especificação

Página de 26
 
 
QS20.241, QS20.241-A1, QS20.241-C1
 
 
Q-Series 
24V,
 
20A,
 
S
INGLE 
P
HASE 
I
NPUT
 
 
 
22.  A
PPLICATION 
N
OTES
 
22.1.  R
EPETITIVE 
P
ULSE 
L
OADING
 
Typically, a load current is not constant and varies over time. This power supply is designed to support loads with a 
higher short-term power demand (=BonusPower
®
). The short-term duration is hardware controlled by an output 
power manager and is available on a repeated basis. If the BonusPower
®
 load lasts longer than the hardware 
controller allows it, the output voltage will dip and the next BonusPower
®
 is available after the BonusPower
®
 recovery 
time (see chapter 6) has elapsed. 
To avoid this, the following rules must be met: 
a) 
The power demand of the pulse must be below 150% of the nominal output power. 
b) 
The duration of the pulse power must be shorter than the allowed BonusPower
®
 time. (see output section) 
c) 
The average (R.M.S.) output current must be below the specified continuous output current.  
If the R.M.S. current is higher, the unit will respond with a thermal shut-down after a period of time. Use the 
maximum duty cycle curve (Fig. 22-2) to check if the average output current is below the nominal current. 
 
 
Fig. 22-1   Repetitive pulse loads, definitions 
 
Fig. 22-2   Max. duty cycle curve 
 
100%
P
PEAK
T
PEAK
P
0
T
0
max.
150%
 
 
150%
100
0
0.2
0.4
0.6
0.8
1.0
DutyCycle
110
120
130
140
P
PEAK
P
0
 = 10%
P
0
 = 50%
P
0
 = 75%
P
0
 = 100%
 
P
Base load (W) 
P
PEAK
  Pulse load (above 100%) 
T
0
 
Duration between pulses (s) 
T
PEAK
  Pulse duration (s) 
 
D
uty
C
ycle
T
0
 =
T
peak 
-
 
 (D
uty
C
ycle
 x T
peak
)
T
peak + 
T
0
T
peak
D
uty
C
ycle 
 =
 
 
Example:  A load is powered continuously with 240W (= 50% of the rated output load). From time to time a peak 
power of 720W (= 150% of the rated output load) is needed for 1 second.  
 
The question is: How often can this pulse be supplied without overloading the power supply? 
 
-  Make a vertical line at P
PEAK
 = 150% and a horizontal line where the vertical line crosses the P
0
 = 50% 
curve. Read the max. duty cycle from the duty cycle-axis  (= 0.37) 
-  Calculate the required pause (base load) length T
0
:  
21/26
-  Result: The required pause length = 1.7s 
-  Max. repetition rate = pulse +pause length = 2.7s 
 
More examples for pulse load compatibility: 
P
PEAK
 
P
0
 
T
PEAK
 
T
0
 
 
P
PEAK
 
P
0
 
T
PEAK
 
T
0
 
720W 480W 
1s  >25s   
720W 240W 
0.1s >0.16s 
720W 0W  1s  >1.3s   
720W 240W 
1s  >1.6s 
600W 240W 
1s  > 
0.75s 
 
720W 240W 
3s  >4.9s 
D
uty
C
ycle
T
0
=
T
peak 
-
 
 (D
uty
C
ycle
 x T
peak
)
0.37
1s
 
-
 
 (0.37 x 1s)
=
= 1.7s
Oct. 2013 / Rev. 2.2 DS-QS20.241-EN 
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted. 
www.pulspower.com   Phone +49 89 9278 0    Germany