Siemens SINAMICS S120 Function Manual page 94

Servo control
3.11 Sensorless operation (without an encoder)
Series reactor
When high-speed special motors are used, or other low leakage induction motors, a series
reactor may be required to ensure stable operation of the current controller.
The series reactor can be integrated via p0353.
Commissioning/optimization
1. Estimate the motor current p1612 on the basis of the mechanical conditions (I = M/kt).
2. Set Kn (p1470) and Tn (p1472) above I/f operation (> p1755). The load moment of inertia
3. Determine the load moment of inertia in the speed range above I/f operation (> p1755) by
Function diagrams (see SINAMICS S120/S150 List Manual)
● 5050 Kp_n-/Tn_n adaptation
● 5060 Torque setpoint, control type switchover
● 5210 Speed controller without encoder
Overview of important parameters (see SINAMICS S120/S150 List Manual)
● p0341[0...n] Motor moment of inertia
● p0342[0...n] Ratio between the total moment of inertia and that of the motor
● p0353[0...n] Motor series inductance
● p0600[0...n] Motor temperature sensor for monitoring
● p0640[0...n] Current limit
● p0642[0...n] Encoderless operation current reduction
● p1300[0...n] Open-loop/closed-loop control operating mode
● p1400.11 Speed control configuration; encoderless operation actual velocity start value
● p1404[0...n] Encoderless operation changeover speed
● r1407.1 CO/BO: Status word speed controller; encoderless operation active
● p1470[0...n] Speed controller encoderless operation P gain
● p1472[0...n] Speed controller encoderless operation integral time
● p1498[0...n] Load moment of inertia
● p1517[0...n] Accelerating torque smoothing time constant
● p1612[0...n] Current setpoint, open-loop control, encoderless
● p1755[0...n] Motor model changeover speed encoderless operation
● p1756 Motor model changeover speed hysteresis
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should be set to zero here (p1498 = 0), since this deactivates part of the torque pre-
control.
setting p1498 via a ramp response (e.g. ramp time 100 ms) and assessing the current
(r0077) and model speed (r0063).
Function Manual, (FH1), 10/2008, 6SL3097-2AB00-0BP5
Drive functions