Structure Diagram Of The Entire Armature Control Loop With An Example - Siemens SINAMICS DCM 6RA80 Faq

Structure diagram of the entire armature control loop with an example

Speed controller with a lower-level current controller and DC motor as the load.
A
Kp, Tn
I*
n*
n-controller
-nact
-Iact
n*: speed setpoint, nact: speed actual value, I*: current setpoint, Iact: actual current value;
Ust: control voltage, U
I : armature current motor, T
A
T : mechanical ramp-up time constant; M
M
n-controller: speed controller, i-controller: current controller
K , T : PT1 element due to armature circuit inductance and armature circuit resistance;
A A
Kp: controller gain, Tn: controller reset time
Example:
B6C circuit, line voltage Us:3AC400 V, armature circuit inductance motor L
rmature circuit resistance motor R
resistance of smoothing reactor R
Voltage drop commutating reactor: Vimp = 4%,
Line frequency: 50 Hz, rated armature current I
firing angle range
Parameters of the dead-time element:
Ideal no-load direct voltage = Udi = Us * 1.35 = 540 V
The trigger firing angle for rated armature voltage
the control characteristic: cos
K = / ( – ) = 90 / (90 – 39) = 1.76
t 1 2
Mean (statistical) dead time for 6-pulse bridge connection (p=6) and 50 Hz:
T = 20 ms / p = 20 / 6 = 3.33 ms, half of which is postulated as the statistical dead time:
t
T = 1.66 ms
t
Parameters of the lag element:
R = R + R + R , d
A M G S
R = 0.02 + 0.005 + 0.018 = 0.043
A
Armature circuit inductance L
Armature circuit gain:
K = U / (I * R ) = 440 / (600*0.043) = 16.3
A AN AN A
Armature time constant = L
If the set current limit is greater than I
formulas. This also applies to the torque M
Kp2, Tn2
K , T
t
Uctr
l
i-controller Dead
: armature voltage, EMF: induced motor voltage,
A
: dead time due to power system cycles,
t
L
: 0.02 ohm, inductance of smoothing reactor L
M
: 5 mOhm, cable deemed negligible.
G
= 90 degrees for 100% in the calculation of the software
= U / Udi = 420 / 540 = 0.778 yields
2 AN
= 0.5 * Vimp = 0.02; R
x
= L + L = 1.5 mH
A M G
-3
/ R = 1.5*10
A A
, this peak current must be substituted in the
AN
K , T
A A
t
U
A
-EMF
: load torque, n : the motor speed
M
: 600 A, rated armature voltage U
AN
is derived from the cosine function of
2
= d * Udi / I = 0.02 * 540 / 600 = 0.018
S x AN
/ 0.043 = 0.0349 s = 34.9 ms = T
for the mechanical ramp-up time constant T
MN
70
M
L
....MOTOR
T
M
I
A
: 0.5 mH,
M
: 1 mH,
G
AN
approx. 39 degrees
2
1
n
M
: 420 V,
.
M