Rockwell Automation 20L, LPM20 PowerFlex 700 Active Converter Power Module - Manual (Page 34)

2-16 Start Up
PowerFlex 700L Active Converter Power Module User Manual
Publication PFLEX-UM002D-EN-P
Voltage Loop Tuning
The tuning of the voltage loop is a function of Converter parameter 162 -
[Capacitance], parameter 163 - [VML bandwidth], and parameter 164 -
[VML Damping]. In most cases, the default values for these three
parameters should not need to be adjusted. When multiple Inverters are on a
common bus, the combined DC link capacitance of the additional inverters
must be entered into parameter 170 - [Bus Capacitance].
Current Loop
The current minor loops regulate the active current as requested by the
voltage major loop, and the reactive current to produce the desired kVAR.
kVAR Control
KVAR Control can be used for power factor compensation.
When parameter 61- [kVAR Reference] is set to zero, the Converter will
regulate reactive current to maintain unity power factor. When a nonzero
value is entered, it requests the amount of kVAR to command. Negative
values are a lagging power factor and positive values are a leading power
factor. When no real current is being delivered by the Converter, the full
current rating of the Converter may be used to produce kVAR. As real
current increases, motoring or regenerating, the reactive current limit is
automatically reduced. The reactive current limit is displayed in parameter
158- [Reactive I Lmt]. The reactive current that is being commanded is
displayed in parameter 159- [Reactive I Cmd].
Current Loop Tuning
The tuning of the current loop is a function of Converter parameter 152 -
[Inductance], parameter 153 - [CML Bandwidth], and parameter 154 -
[CML Damping]. In most cases, the default values for these three
parameters should not need to be adjusted. If a non-standard input filter is
used, the new inductance needs to be entered. When the AC line voltage has
greater than 5% impedance, the CML bandwidth may need to be reduced.
PWM Carrier Synchronization
The converter has the option to synchronize its PWM carrier frequency to
the PWM carrier frequency of the inverter to reduce the common mode
voltage on the motor. This requires the Inverter carrier frequency to be set to
4 kHz.
PWM carrier synchronization is enabled by setting parameter 51- [Option
Select] bit 3 (PWM SyncRecv). After carrier synchronization is completed,
the Converter sets parameter 71 - [Converter Status] bit 9 (PWM
SyncLock). When PWM SyncRecv is set and sync is not locked, the
Converter is inhibited from starting. If sync is lost while the Converter is in