Speed Controller - Siemens SINAMICS S120 Function Manual

6.4

Speed controller

Overview
The control modes with/without encoder have the same speed controller structure. The speed
controller structure comprises the following components:
● PI controller
● Speed controller precontrol
● Droop
The total of the output variables result in the torque setpoint which is reduced to the permissible
magnitude by means of the torque setpoint limitation.
Function description
The speed controller receives its setpoint (r0062) from the setpoint channel and its actual value
(r0063) either directly from the speed sensor (control with sensor (VC)) or indirectly via the
motor model (control without sensor (SLVC)). The system deviation is increased by the PI
controller and, in conjunction with the precontrol, results in the torque setpoint.
When the load torque increases, the speed setpoint is reduced proportionately when droop is
active, which means that the single drive within a group (two or more mechanically connected
motors) is relieved when the torque becomes too large.
Figure 6-6
The optimum speed controller setting can be determined via the automatic speed controller
tuning function (p1900 = 1, rotating measurement).
If the moment of inertia has been specified, the speed controller (K
means of automatic parameterization (p0340 = 4). The controller parameters are defined in
accordance with the symmetrical optimum as follows:
Drive functions
Function Manual, 06/2019, 6SL3097-5AB00-0BP2
Overview: Speed controller
Vector control
6.4 Speed controller
, T ) can be calculated by
p n
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