Sensorless Vector - Allen-Bradley Kinetix 5700 User Manual

Sensorless Vector

The Sensorless Vector method uses a volts/hertz core enhanced by a current
resolver, slip estimator, and a voltage-boost compensator based on the
operating conditions of the motor.
Figure 212 - Sensorless Vector Method
Motor Pole
Velocity Trim
Velocity Command
+
Slip Speed
Estimation
The algorithms operate on the knowledge of the relationship between the
rated slip and torque of the motor. The drive uses applied voltages and
measured currents to estimate operating slip-frequency. You can enter values to
identify the motor resistance value or you can run a motor test to identify the
motor resistance value (see
Motor nameplate data and test results are ways to accurately estimate the
required boost voltage.
The sensorless vector method offers better torque production and speed
regulation over a wider speed range than basic volts/hertz.
Dynamic boost is applied internally to compensate voltage drop and improve
starting torque.
Figure 213 - Approximate Load Curve
Dynamic Boost Applied
Rockwell Automation Publication 2198-UM002G-EN-P - February 2019
Pairs
x V/Hz
+
Torque
Estimate
Load
Slip
Torque
Estimator
Motor Tests and Autotune Procedure
Voltage, max
Base Voltage
(nameplate)
Motor Control Feature Support
Voltage
Inverter
Control
Vboost
Estimator
Current
Feedback
Current
Resolver
Ideal, volts/hertz
Frequency,
Base Frequency,
max
(nameplate)
Appendix E
Motor
on page 422).
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