Siemens 420 manual 21.1.2 V/f open-loop control with flux current control FCC

Issue 07/04 3 Functions

3.21.1.2V/f open-loop control with flux current control (FCC)

Parameter range:	P1300, P1333
Warnings	-
Faults	-
Function chart number:	-

An improved current measurement function has been developed for our MICROMASTER drive inverters. This permits the output current to be precisely determined referred to the motor voltage. This measurement guarantees that the output current is sub-divided into a load component and a flux component. Using this sub-division, the motor flux can be controlled and can be appropriately adapted and optimized in- line with the prevailing conditions.

i load

i total

i flux

FCC operation is only activated after the FCC starting

frequency P1333 has been exceeded. The FCC starting frequency P1333 is entered as a percentage to the rated motor frequency P0310. For a rated motor frequency of 50 Hz and a factory setting of P1333 = 10 %, this results in an FCC starting frequency of 5 Hz. The FCC starting frequency may not be selected too low as this has a negative impact on the control characteristics and can result in oscillation and system instability.

The "V/f with FCC" control type (P1300 = 1) has proven itself in many applications. It has the following advantages with respect to the standard V/f control:

Higher motor efficiency

Improved stabilizing characteristics

♦→ higher dynamic response

♦→ improved behavior to disturbances / control

MICROMASTER 420	Operating Instructions
6SE6400-5AA00-0BP0	147