Siemens SINAMICS G120 CU230P-2, Operating Instructions Manual, Page: 209 / 346

Functions
7.6 Motor control
Frequency inverters with Control Units CU230P-2 HVAC, CU230P-2 DP, CU230P-2 CAN
Operating Instructions, 01/2011, FW 4.4, A5E02430659B AD
207
7.6.1.2 Additional characteristics for the V/f control
In addition to linear and square-law characteristics, there are the following additional
versions of the V/f control that are suitable for special applications.
Linear V/f characteristic with Flux Current Control (FCC) (P1300 = 1)
Voltage losses across the stator resistance are automatically compensated. This is
particularly useful for small motors since they have a relatively high stator resistance. The
prerequisite is that the value of the stator resistance in P350 is parameterized as accurately
as possible.
V/f control with parameterizable characteristic (p1300 = 3)
Variable V/f characteristic that
supports the torque response of
synchronous motors (SIEMOSYN
motors).
I
PD[
8
RXWSXW
PD[
U
8
I
U
8S
8S
8S
IS IS IS IS
8S
Linear V/f characteristic with ECO (p1300 = 4), quadratic V/f characteristic with ECO (p1300 = 7)
ECO mode is suitable for applications with a low dynamic response and constant speed
setpoint, and allows energy savings of up to 40%.
When the setpoint is reached and remains unchanged for 5 s, the inverter automatically
reduces its output voltage to optimize the motor's operating point. ECO mode is deactivated
in the event of setpoint changes or if the inverter's DC-link voltage is too high or too low.
In ECO mode set the slip compensation (P1335) to 100 %. In the event of minor fluctuations
in the setpoint, you have to raise the ramp-function generator tolerance using p1148.
Note: Sudden load variations can cause the motor to stall.