Siemens SINAMICS DCM Operating Instructions Manual page 282

Commissioning
8.8 Manual optimization
Overall optimization of the armature circuit
 Checking the precontrol characteristic
 Checking the step response
280
 Calculate the armature circuit resistance p50110 from the armature current and
armature voltage
-Gradually increase the main setpoint (shown at r52011) until the actual
armature current value (r50019 as a % of the unit's rated armature current)
reaches approximately 70% of the motor's rated armature current.
-Calculate the armature circuit resistance:
Ra[Ω] = r50038 / (r50019 × p50100) = armature voltage [V] / armature current
[A]
 Calculate the armature circuit inductance p50111 from the armature current at the
transition point from discontinuous to continuous current
-Make an oscilloscope trace of the armature current.
-Starting from 0, gradually increase the main setpoint (shown at r52011) until
the armature current reaches the transition point from discontinuous to
continuous current.
-Calculate the armature circuit inductance using the following formula:
La[mH] = 0.4 × r50015 / (r50019 × p50100)
= armature voltage [V] / armature current at the transition point from
discontinuous to continuous current [A]
Procedure
- Set the function generator to a triangular waveform (0 % to 100 %), period =
10000 ms
- Supply point: p50601[4] (see function diagram 6855)
- Set p50082 = 0 (field off)
- p50153 = 3 (influence of EMF disabled)
- Record signals r52121 (output, precontrol) and r52110 (output, armature current
controller)
- The parameters of the precontrol (Ra [p50110], La [p50111] and λa [p51591]) are
correctly set if the armature current controller output has the lowest possible value
(e.g. less than 5 %) over the complete setpoint range.
Procedure
- Set the function generator to a squarewave, with
step height = e.g. 5 %
offset = various values, e.g. 80 %
period = 1000 ms
pulse width = 500 ms
- Supply point: p50601[4] (see function diagram 6855)
- Set p50082 = 0 (field off)
- Record signals r52118 (Ia-set) and r52117 (Ia-act)
Operating Instructions, 1.2012, C98130-A7066-A1-05-7619
SINAMICS DCM DC Converter