Rockwell Automation Publication DRIVES-AT005D-EN-P - May 2022 21
Chapter 2 Regenerative Bus Supply Configuration
PowerFlex 755T active front end products monitor for line-side resonance currents. Detection is a key to help prevent unexpected power system
resonance failures. When system resonance is detected, the PowerFlex 755T active front end products continue operation and provide an early-
warning of line-side resonance through alarm 14117 'CapHighResonance'. When power system resonance levels surpass thresholds for reliable
operation, 14118 'CapOverResonance' provides a fault. You have the option to configure the desired response to a system over resonance
condition using parameter 0:453 [CapOvrRsncActn]. See the PowerFlex Drives with TotalFORCE Control Programming Manual, publication
750-PM100
, for more information.
Dynamic Bus Control for Large Capacitor Bank Applications
Dynamic Bus control is a mode of bus voltage control in PowerFlex 755TM regenerative bus supplies and 755TR regenerative drives. Dynamic Bus
control allows the PowerFlex 755TM regenerative bus supply to utilize the energy in an externally connected capacitor bank by not regulating the DC
Bus voltage at one set level. The DC Bus voltage is regulated between three voltage setpoints, depending on the state of operation.
The PowerFlex 755TM regenerative bus supply in regenerating mode allows DC Bus voltage at a higher level, so that the capacitor bank can absorb
regenerative energy before regenerating to the AC line. As the system begins motoring, the PowerFlex 755TM regenerative bus supply allows a lower
DC Bus voltage to utilize the stored energy in the external capacitor bank before sourcing the AC line.
Dynamic Bus control allows for smoothing of the AC line side current by modifying the motoring and regenerating power limits constantly as the DC
Bus voltage increases and decreases.
The following procedure describes the steps that are required for configuring Dynamic Bus Control in the PowerFlex 755TM regenerative bus supply.
1. Figure 9 on page 18
shows the standard system configuration. When using external capacitor banks, verify that the PowerFlex 755TM
regenerative bus supply does not exceed the maximum external capacitance supported. See Appendix A
.
2. PowerFlex 755TM regenerative bus supply parameter configuration. The following example shows the possible settings for an additional
capacitor bank for a 480V AC voltage class system. Your system will vary.
a. Set Parameter 13:45 [DC Bus Ref Sel] = DBC
b. Set Parameter 13:61 [DBC Mode Sel] = Nonlinear (Default)
c. Set Parameter 13:62 [DBC V Thresh Lo] = 660V DC (Based on PowerFlex 755TM Voltage Class)
d. Set Parameter 13:63 [DBC V Thresh Hi] = 780V DC (Based on PowerFlex 755TM Voltage Class)
e. Set Parameter 13:64 [DBC V Thresh Nom] = 690V DC (Based on PowerFlex 755TM Voltage Class)
f. Set Parameter 13:105 [Motor Power Lmt] = 100%
g. Set Parameter 13:333 [DBC IdleRgnPwrLm] = 5%
h. Set Parameter 13:332 [DBC NomRgnPwrLm] = 30%
i. Set Parameter 13:104 [Regen Power Lmt] = 100%
j. Set Parameter 13:331 [DBC IdleMtrPwrLm] = 5%
k. Set Parameter 13:330 [DBC NomMtrPwrLm] = 30%
Figure 10 on page 22
is an example of non-linear operation of the power limits. The DC bus voltages that are shown are for a 480V AC voltage class
system. The DC bus voltages are different for other AC voltage class systems. These curves can be adjusted using the nominal motoring and regen
power limits.
To Next Page
Loading...
Need help?
General
