Introduction, V/F Control, Vector Control - Siemens SINAMICS G120D Operating Instructions Manual

Commissioning
5.2 Preparing for commissioning
5.2.2

Introduction, V/f control, vector control

Specifying the control mode
The converter has three open-loop control and closed-loop control modes for induction
motors:
● Open-loop control with U/f-characteristic (U/f control)
● Field-oriented control (sensorless vector control)
● Speed control (vector control with encoder)
The control modes have different degrees of suitability when it comes to controlling a
position-controlled axis:
Vector control with encoder
With the position control, provides the best
results
It is not permissible to use vector control in the following cases:
● If the motor is too small in comparison to the inverter (the rated motor power may not be
less than one quarter of the rated inverter power)
● If several motors are connected to one inverter
● If a power contactor is used between the inverter and motor and is opened while the
motor is powered up
● If the maximum motor speed exceeds the following values:
Pole number of the motor
Maximum motor speed [rpm]
62
Sensorless vector control
Limited functionality of the position
control.
Low accuracy
•
Travel to fixed stop is not possi-
•
ble
Inverter pulse frequency
U/f control
Not recommended in conjunction
with position control.
Low accuracy
•
Low dynamic response
•
Travel to fixed stop is not possi-
•
ble
2 kHz
2-pole 4-pole 6-pole
9960 4980 3320
Converter with control units CU250D-2
Operating Instructions, 04/2015, FW V4.7.3, A5E34261542B AB
4 kHz and higher
2-pole 4-pole 6-pole
14400 7200 4800