Siemens SINAMICS G120D - Introduction, V;F Control, Vector Control

Commissioning
5.2 Preparing for commissioning
Converter with control units CU250D-2
62 Operating Instructions, 04/2015, FW V4.7.3, A5E34261542B AB
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
Sensorless vector control
U/f control
With the position control, provides the best
results
Limited functionality of the position
control.
• Low accuracy
• Travel to fixed stop is not possi-
ble
Not recommended in conjunction
with position control.
• Low accuracy
• Low dynamic response
• Travel to fixed stop is not possi-
ble
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:
Inverter pulse frequency
2 kHz
4 kHz and higher
Pole number of the motor
2-pole
4-pole
6-pole
2-pole
4-pole
6-pole
Maximum motor speed [rpm]
9960
4980
3320
14400
7200
4800