Flux Reference Handling; Flux Reference In Emergency Stop; Emf Reference Handling; Pi - Controller - ABB DCS 500B Description

Functional Software description
FLUX reference
handling
Flux Reference in
Emergency Stop
EMF reference
handling

PI - controller

62
SPEED SCALING (2103)
rpm value equals to spped reference value of 20000.
FIELD WEAK POINT (1012)
Motor field weakening point. Scaling in speed units.
Example. The motor is labeled 1500 - 1800 rpm, 440V
Set SPEED SCALING (2103)
Set FIELD WEAK POINT (1012) = 16666 (=1500 * 20000 / 1800 )
The FLUX reference can be selected by input [FLUX REF SEL]
(1004) as follows: The constant 100% flux reference (= 4096 units
in software) is selected if input [FLUX REF SEL] (1004) has value
0. Value 1 selects the flux reference from input [FLUX REF] (1002),
which is connected to the application program (by means of func-
tion blocks in DCS 500B), when there are special requirements
from the process point of view.
When the motor FLUX is reduced, a larger amount of armature cur-
rent is needed to create the same torque on the motor shaft. This
can be used on some applications, e.g. unwinder section in a
winder. Because of a bigger armature current, the resolution of the
measurement is better, which helps to control small torques with
good accuracy.
Normally the FLUX reference is not changed rapidly. For example,
on unwinder the FLUX reference follows the diameter of the roll.
The control range for FLUX is 1:5, so the minimum FLUX reference
is 20% of nominal. In case of EMERGENCY STOP, the reduced
FLUX reference is changed to maximum possible FLUX reference
defined by the field weakening area.
The EMF reference is selected by input [EMF REF SEL] (1005).
Value 1 selects the EMF-reference from input [EMF REF] (1003) ,
which is connected to the application program. Value 0 selects pa-
rameter LOCAL EMF REF (1006) as the EMF reference.
The scaling of LOCAL EMF REF (1006) is:
100% = U MOTN V
PI-controller is needed to correct inaccuracies caused by the proc-
ess, e.g. network AC voltage variations.
I-part of the controller is reset below a certain EMF-level because
the rotor resistance value I R would otherwise cause an
Max. speed of drive in 0.1 rpm. This
= 18000
DCS 500 Software Description