Vector Control With Encoder - Siemens SINAMICS S150 NEMA Operating Instructions Manual

7.4.2

Vector control with encoder

Description
Benefits of vector control with an encoder:
● The speed can be controlled right down to 0 Hz (standstill)
● Stable control response throughout the entire speed range
● Allows a defined and/or variable torque for speeds below approx. 10% of the rated motor
speed to be maintained
● Compared with speed control without an encoder, the dynamic response of drives with an
encoder is significantly better because the speed is measured directly and integrated in
the model created for the current components.
Motor model change
A model change takes place between the current model and the observer model within the
speed range p1752 x (100% - p1753) and p1752. In the current-model range (i.e., at lower
speeds), torque accuracy depends on whether thermal tracking of the rotor resistance is
carried out correctly. In the observer-model range and at speeds of less than approx. 20% of
the rated speed, torque accuracy depends primarily on whether thermal tracking of the stator
resistance is carried out correctly. If the resistance of the supply cable is greater than 20 to
30% of the total resistance, this should be entered in p0352 before motor data identification
is carried out (p1900/p1910).
To deactivate thermal adaptation, set p0620 = 0. This may be necessary if adaptation cannot
function accurately enough due to the following general conditions.
Causes of inaccuracies:
● A sensor is not used for the temperature measurement and the ambient temperatures
fluctuate significantly.
● The motor overtemperatures (p0626 to p0628) deviate greatly from the default settings as
a result of its design.
Function diagrams
FP 4715
FD 6030
FP 6040
FP 6050
FP 6060
FP 6490
Enclosed Drives
Operating Instructions, 12/2018, A5E36652151A
Actual speed value and rotor position measurement, motor encoder
Speed setpoint, droop
Speed controller with/without encoder
Speed controller adaptation (Kp_n/Tn_n adaptation)
Torque setpoint
Speed control configuration
Setpoint channel and closed-loop control
7.4 Vector speed/torque control with/without an encoder
465