Open Loop Vector Control (Olvc) - Siemens SINAMICS PERFECT HARMONY GH180 Function Manual

NXGPro+ Control Description
4.7 Control Modes
Control Mode
Volts / Hertz control
mode (V/Hz)
Closed loop vector con‐
trol mode (CLVC)
Closed synchronous
motor control mode
(CSMC)
Permanent magnet mo‐
tor control mode (PMM)
Synchronous motor
brushless DC exciter
mode (SMDC)
4.7.4

Open Loop Vector Control (OLVC)

Open loop vector control (OLVC) is used for most applications with single induction motors. In
this mode, the control estimates motor slip as a function of load torque, and provides a
performance that matches a vector controlled drive with speed sensor/transducer above a
certain minimum speed. With the correct motor parameters, the control can provide good
performance even at 1% of rated speed.
With this mode, speed feedback is synthesized from the stator frequency and the estimated
motor slip, and slip compensation is automatic.
In this control mode, if spinning load is selected, the drive begins by scanning the frequency
range to detect the speed of the rotating motor. Once the drive has completed the scan or if the
feature is disabled, the drive goes into magnetizing state. During this state, the drive ramps the
motor flux to its commanded value at the specified flux ramp rate. Only when the flux feedback
is within 90% of the commanded flux, the drive changes to the run state. Once in run state, the
drive increases the speed to the desired value. All motor and drive parameters are required for
this mode of operation. Default values for the control loop gains are sufficient for most
applications.
50
Vector Control Type of Motor
No vector control Induction - usually mu‐
liple connected in par‐
allel
Vector control Induction
Vector control Synchronous
Vector control Permanent magnet
motor
Vector control Synchronous with DC
exciter
Encoder Features
Without encoder
•
•
With encoder
•
•
With encoder
•
•
Without encoder
•
•
•
Without encoder
•
•
Operating Manual, A5E50491925A
No fast bypass
No spinning load
Fast bypass option
Spinning load op‐
tion
Fast bypass option
Spinning load op‐
tion
Fast bypass option
No spinning load
High starting tor‐
que enabled auto‐
matically
No fast bypass
No spinning load
NXGPro+ Control Manual