V VW Vector Control
CFW501 | 10-1
10
10 V VW 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: VVW control flow 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 speed 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 VVW 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 VVW control instantly obtains the motor torque and slip. Thus, the
VVW actuates in the output voltage compensation and slip compensation. Therefore, the VVW controller action
replaces the classical V/f functions in P0137 and P0138, 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 speed regulation in permanent duty, the parameter setting in the range from P0399
to P0407 and the stator resistance in P0409 are essential for the good operation of the VVW control. Those
parameters can easily be obtained on the motor nameplate and in the self-tuning routine activated by P0408.
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