VFD static tune used to calculate stator voltage drop

[philly]

I've noticed that when tuning a motor on a VFD one of the static tune used with the motor uncoupled is to calculate the voltage drop across the stator windings? How does the information from this tune help control the drive in a vector mode?

I believe the drive outputs a current and then measures the voltage drop across the windings using this current? Where and how does it measure the voltage?

How is this value used to control torque or speed in sensorless vector control?

 

[weressl]

I've noticed that when tuning a motor on a VFD one of the static tune used with the motor uncoupled is to calculate the voltage drop across the stator windings? How does the information from this tune help control the drive in a vector mode?

I believe the drive outputs a current and then measures the voltage drop across the windings using this current? Where and how does it measure the voltage?

How is this value used to control torque or speed in sensorless vector control?

It is much more than just a voltage drop calculation. The magnetizing current injection allows the drive to build and actual motor model including the feeder cables and the driven inertia, from the motor data that is collected by the drive manufacturer and built into the drive. What the actual model is of course varies between manufacturers and makes a BIG difference how well the drive will perform.