13
Based on the system power profile, the following system level DC link power
values are defined.
Average motoring power P
mot,ave
P
mot,ave
is the average of the
motoring
DC link power over the whole cycle.
This power is taken from the AC supply. For long load cycles
P
mot,ave
should
be determined over the worst-case 3 minutes time window.
Peak motoring power P
mot,max
P
mot,max
is the positive peak power in the power profile. This value can have a
major impact on the selection of the drive module(s) connected to the AC
supply, if many axes are accelerated simultaneously.
Average regenerative power P
gen,ave
P
gen,ave
is the average of the
regenerating
DC link power over the whole
cycle. This power must be dissipated in braking resistor(s) or fed back to the
AC supply.
P
gen,ave
should be determined over the worst-case 30 seconds
time window, if the internal braking chopper of the ACSM1 is used.
Peak regenerative power P
gen,max
P
gen,max
is the negative peak power in the power profile. This value has a
major impact on the number of active braking choppers needed.
The power values defined above are shown in the following diagram.
~
=
~
=
~
=
~
=
~
=
Pdc
1
M
1
M
2
M
3
M
n
R
2
R
3
Braking
resistor(s)
S
ys
te
m
p
ow
er
p
ro
file
P
mot,ave
P
mot,max
P
gen,ave
P
gen,max
Pdc
2
Pdc
3
Pdc
n