Rockwell Automation 20G PowerFlex 750-Series AC Drives - Manual (Page 229)

Rockwell Automation Publication 750-RM002B-EN-P - September 2013 229
Motor Control Chapter 4
1 = “Fan/Pump”
When this option is chosen, the relationship is 1/x2. Therefore, at full frequency,
full voltage is supplied. At 1/2 rated frequency, 1/4 voltage is applied. This
pattern closely matches the torque requirement of a variable torque load
(centrifugal fan or pump – load increases as speed increases) and offers the best
energy savings for these applications.
Sensorless Vector
Sensorless Vector mode uses a V/Hz core enhanced by excellent current
resolution, a slip estimator, a high performance current limiter and the vector
algorithms. The basic functions for SV are similar for all three motor types,
induction motor, permanent magnet motor, and synchronous reluctance motor,
however PM and SyncRel SV do not require Slip Frequency adjustments.
IM Sensorless Vector
Maximum Voltage
Base Voltage
(Nameplate)
Run Boost
Break Frequency
(Nameplate)
Maximum
Frequency
+
+ Elec. Freq. V Ref.
Gate
Signals
V/Hz
Voltage
Control
Inverter Motor
Current
Limit
Freq. Ref. Speed Freq.
Current
Resolver
Current Feedback
Current Feedback - Total
Torque 1 Est.
Vector
Control
V Vector
Slip
Estimator
Torque 1 Est.
To
rq
ue
1
Es
t.
V/Hz Control
Slip Frequency