Tuning Of Current Regulator; Firing Angle Limitation; Additional Commutation Reserve Dxn; Example - ABB DCS 500B Description

Tuning of Current
Regulator
Firing Angle
Limitation
Additional Com-
mutation Reserve
DXN

Example

DCS 500 Software Description
Tuning of the regulator can be done either manually with response
tests or with autotuning function, which is activated by setting pa-
rameter DRIVE MODE (1201) to 3, when the drive's main contactor
is open. After closing of the main contactor and starting of the
drive, the autotuning procedure for the armature current controller
will start. The DRIVE MODE (1201) value is set to 0 when auto-
tuning is completed. The autotuning proceeds without user inter-
vention. Motor data have to be set correctly before autotuning is
started. More information about tuning can be read in chapter
Start-up.
The output signal of the regulator is the firing angle reference (1 =
1°) ARM ALPHA (10401). Its minimum value is limited by means of
parameter:
The maximum output voltage of the thyristor bridge is limited by
parameter ARM ALPHA LIM MIN (413), default value =15
The armature voltage is
current is continuous. α = ARM ALPHA.
For example, if U
SUPPLY
voltage is 1.35 * 400 V * Cos 15° = 521 V.
The maximum firing angle is limited by parameter
ARM ALPHA LIM MAX (412), default value = 150. Do not change
this value without consulting ABB!
The commutation can not take place infinitely fast because of the
network reactance. The time for the commutation can be ex-
pressed by the commutation angle u, which can be calculated us-
ing formula:
u = arc cos (cos α - I d / I k ) - α
where I k = short circuit current
I d = load current
U l = network voltage
X l = network total reactance
It is wanted that a "weak" network can commutate 600 A current.
The nominal voltage of the network is 380 V and frequency 50 Hz.
Used transformer:
20 kV/400 V, 500 kVA
R k = 0.0032 Ω
L km = 48.85 µH/phase
Cable: lenght 50 m, 250 µH/km, L kk = 12.5 µH/phase
Functional Software description
U = 1.35 * U
SUPPLY
is 400 V AC, the maximum armature
* Cos α, if the
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