Rockwell Automation Allen-Bradley PowerFlex 755T Flux Vector Tuning User Manual

Rockwell Automation Publication 750-AT006D-EN-P - January 2022 97
Chapter 6 Active Front End Tuning
Reactive Power Control
Reactive power control is another capability of the PowerFlex 755T product family where, in addition to providing bidirectional power flow
to/from the load, the AFE power converter can supply/absorb reactive power to/from the system. This helps enhance the power factor and
the efficiency of the utility. The total supplied active and reactive power should not increase the total thermal capacity of the system.
The reference reactive power command can be set using 13:69 [KVAR Ref]. The commanded reactive power is displayed in
13:72 [KVAR Command]. The commanded reactive power depends mainly on the active power loading condition, thermal capacity of the
drive, and the DC bus voltage in 0:3 [DC Bus Volts]. By default, active power is prioritized and the remainder of the thermal capacity can be
utilized for reactive power control. The drive can be configured to only supply reactive power to the line through 13:40 [Conv Options Config]
Bit 7 Cfg:VAR OnlyMode.
If the Var Control option is selected in 13:45 [DC Bus Ref Sel], the DC bus is automatically adjusted based on the commanded reactive power
that is displayed in 13:72 [KVAR Command]. A simplified equivalent circuit of the power converter is shown in Figure 79
. The power converter
is represented as a voltage source connected to the grid through a source inductance. Figure 80 shows the corresponding phasor diagram
in regenerative mode. The converter output voltage increases when it injects reactive power to the grid, as compared to that of unity power
factor. In this case, the DC bus needs to be increased to be able to generate the appropriate output voltage. The commanded DC bus voltage
reference is automatically adjusted based on the phasor diagrams below. The inherent uncertainty in the actual value of the source
inductance is compensated for by an internal regulator that is designed to trim the commanded DC bus voltage of the power converter, this
13:176 [LSCPhLossDetActn]
LSC Input Phase Loss
Detected Action
Enter a value to select the action taken when an Input Phase Loss condition occurs. Parameter values are
as follows.
• Ignore (0) – No action is taken.
• Type 2 Alarm (1) – A Type 2 Alarm occurs.
– Type 2 Alarms prevent the line-side converter from starting its modulation.
• Ride Thru (2) – The line-side converter pauses modulation for the duration of the Ride Through Timer.
– If the Input Phase Loss condition clears before the timer expires, it resumes operation.
– During the Ride Through attempt, it logs a Type 2 Alarm.
• Major Fault (3) – A Major Fault occurs immediately.
– Major Faults stop the line-side converter from modulating.
13:177 [PhsLossRTExpActn]
Input Phase Loss Ride
Through Expire Action
Enter a value to select the action taken when the Input Phase Loss condition lasts longer than the Ride
Through Timer. Parameter values are as follows.
• Ignore (0) – No action is taken.
• Type 2 Alarm (1) – A Type 2 Alarm occurs.
– Type 2 Alarms prevent the line-side converter from starting its modulation.
• Major Fault (2) – A Major Fault occurs immediately.
– Major Faults stop the line-side converter from modulating.
13:179 [DFDT Det Actn]
Frequency Rate of
Change Detected
Action
Enter a value to select the action taken when a DFDT condition occurs. A DFDT condition is when the rate of
change of frequency is too high. Parameter values are as follows.
• Ignore (0) – No action is taken.
• Type 2 Alarm (1) – A Type 2 Alarm occurs.
– Type 2 Alarms prevent the line-side converter from starting its modulation.
• Ride Thru (2) – The line-side converter pauses modulation for the duration of the Ride Through Timer.
– If the DFDT condition clears before the timer expires, it resumes operation.
– During the Ride Through attempt, it logs a Type 2 Alarm.
• Major Fault (3) – A Major Fault occurs immediately.
– Major Faults stop the line-side converter from modulating.
13:180 [DFDTRdThrExpActn]
Freq Rate Of Change
Ride Through Expire
Action
Enter a value to select the action taken when the DFDT Loss condition lasts longer than the Ride Through
Timer. Parameter values are as follows.
• Ignore (0) – No action is taken.
• Type 2 Alarm (1) – A Type 2 Alarm occurs.
– Type 2 Alarms prevent the line-side converter from starting its modulation.
• Major Fault (2) – A Major Fault occurs immediately.
– Major Faults stop the line-side converter from modulating.
13:181 [PLL LOS Det Actn]
PLL Sync Loss
Detected Action
Enter a value to select the action taken when a Phase Lock Loop Loss of Synchronization condition occurs.
Parameter values are as follows.
• Ride Thru (0) – The line-side converter pauses modulation for the duration of the Ride Through Timer.
– If the Phase Lock Loop Loss of Synchronization condition clears before the timer expires, it resumes
operation.
– During the Ride Through attempt, it logs a Type 2 Alarm.
– If the Phase Lock Loop Loss of Synchronization condition lasts longer than the Ride Through Timer, a
Major Fault occurs and the line-side converter stops modulating.
• Major Fault (1) – A Major Fault occurs immediately.
– Major Faults stop the line-side converter from modulating.
Table 34 - Abnormal Line Conditions Parameter Settings (Continued)
Parameter No. Parameter Name Description

Rockwell Automation Allen-Bradley PowerFlex 755T Flux Vector Tuning Specifications

General

Brand	Rockwell Automation
Model	Allen-Bradley PowerFlex 755T Flux Vector Tuning
Category	Industrial Equipment
Language	English