122 Rockwell Automation Publication PFLEX-RM003E-EN-E - January 2011
Chapter 1 Detailed Drive Operation
Sensorless Operation
Sensorless mode is used when zero speed or more than a 120:1 speed range is not
required.
The drive is set for sensorless operation when parameter 485 [Motor Ctrl Mode]
is set to 0 “FOC” and parameter 222 [Mtr Fdbk Sel Pri] = 2 “Sensorless”.
Sensorless operation can also occur when the drive is configured for speed
feedback ride through and parameter 223 [Mtr Fdbk Sel Alt] = 2 “Sensorless”
(refer to Speed Feedback Loss Ride Through
on page 141 for details).
Slip Compensation
When the drive is configured for sensorless operation, slip compensation should
be enabled by setting parameter 153 [Control Options], bit 19 “SlipComp En” =
1.
The amount of slip compensation to provide is set in parameter 98 [Slip RPM @
FLA]. If desired, you may adjust parameter 98 to provide more or less slip. Refer
to Slip Compensation
on page 126 for more details.
Sensorless Gains
There are separate gains used to tune the speed regulator for sensorless operation.
This allows the user to set different gains for operation with feedback and
sensorless operation when using speed feedback loss ride through.
Parameter 106 [Srlss Spd Reg BW] sets the speed regulator bandwidth in
sensorless mode. Increasing the value of [Srlss Spd Reg BW] makes the speed
regulator more responsive.
Parameter 104 [Srlss Spd Reg Kp] sets the proportional gain of the speed
regulator in sensorless mode. It's value is automatically calculated based on the
bandwidth setting in parameter 106 [Srlss Spd Reg BW] and parameter 9 [Total
Inertia]. Proportional gain may be manually adjusted by setting parameter 90
[Spd Reg BW] to a value of zero. Units are (per unit torque) / (per unit speed).
For example, when parameter 81 [Spd Reg P Gain] is 20, the proportional gain
block will output 20% motor rated torque for every 1% error of motor rated
speed.
Parameter 105 [Srlss Spd Reg Ki] sets the integral gain of the speed regulator in
sensorless mode. It's value is automatically calculated based on the bandwidth
setting in [Srlss Spd Reg BW] and the inertia of the system in [Total Inertia].
Integral gain may be manually adjusted by setting [Spd Reg BW] to a value of
zero. Units are (per unit torque/sec) / (per unit speed). For example, when
parameter 82 [Spd Reg I Gain] is 50 and the speed error is 1%, the integral output
will integrate from 0 to 50% motor rated torque in 1 second.
To Next Page
Loading...
Need help?
General
