Beckhoff PS3031-4820-0000, Documentation

Page: 32 / 45

Application notes
PS3031-4820-0000 32 Version: 1.0
4 Application notes
4.1 Repeated pulse load
Typically a load current is not constant and varies with time. This power supply is designed to support loads
with a higher short-term power demand (extra power). The short-term duration is hardware-controlled by an
output power manager and is available repeatedly. If the extra power load lasts longer than the hardware
controller allows, the output voltage drops. Extra power is available again after the extra power recovery time
has elapsed (see
Output [ } 13] chapter).
To avoid this, the following conditions must be met:
• The power requirement of the pulse must be less than 150% of the rated output power.
• The duration of the pulse power must be shorter than the permitted extra power time. (see Output
power section [ } 13] )
• The average (RMS) output current must be below the specified continuous output current.
If the effective current is higher, the device responds with a thermal shutdown after a certain time. The
maximum duty cycle curve (Fig.
Repeated pulse loads, definitions ) can be used to check whether the
average output current is below the rated current.
• The duty cycle must be less than 0.75.
Fig. 21: Repeated pulse loads, definitions; Max. duty cycle curve
Key
P
0
Base load (W)
P
PEAK
Pulse load (over 100%)
T
0
Duration between pulses (s)
T
PEAK
Pulse duration (s)
Calculation:
Duty cycle = T
PEAK
/ (T
PEAK
+ T
0
)
T
0
= (T
PEAK
- (DutyCycle x T
PEAK
)) / DutyCycle