WEG CFW300 V1.3X, Programming Manual

Page: 73 / 157

VVW Vector Control
CFW300 | 10-1
10
10 VVW VECTOR CONTROL
The V VW vector control mode (Voltage Vector WEG) uses a control method with a much higher performance
than the V/f control because of the load torque estimation and of the control of the magnetic flux in the air gap, as
per scheme of
Figure 10.1 on page 10-2 . In this control strategy, losses, efficiency, rated slip and power factor of
the motor are considered in order to improve the control performance.
The main advantage compared to the V/f control is the best frequency regulation with greater torque capacity at
low speeds (frequencies below 5 Hz), allowing a relevant improvement in the drive performance in permanent
duty. Besides, the V VW control has a quick and simple setting and it is suitable for most medium-performance
applications in the control of three-phase induction motor.
By just measuring the output current, the V VW control instantly obtains the motor torque and slip. Thus, the
V VW actuates in the output voltage compensation and slip compensation. Therefore, the V VW controller action
replaces the classical V/f functions in P137 and P138, but with a calculation model much more sophisticated and
accurate, meeting several load conditions or operation points of the application.
In order to achieve a good frequency regulation in permanent duty with a good operation of the V VW control, the
parameter setting in the range P399 to P407, and the stator resistance in P409 are essential for the good operation
of the V VW control. These parameters can be easily obtained on the motor nameplate.