Rockwell Automation 8720MC 8720MC Regenerative Power Supply User Manual - Manual (Page 96)

U.002 REV Current Limit
This parameter limits
current flowing from the
8720MC-RPS
Regenerative Power
Supply unit to the AC input
power during operation. Parameter Range: 0 to 150%
Default Setting: 150%
Parameter Type: Configurable only when the unit is normal
Refer also to Parameters: U.000 DC Bus Voltage Reference
U.001 FWD Current Limit
F.002 Rated Current
Set the REV current value (flowing in the direction to power regeneration) to be limited as a ratio (%) of the
Rated Current (F.002). What is to be limited is the current value flowing by the PWM switching.
When the set value of the REV Current Limit is too small, the DC bus voltage might not go down to the set
value of the DC Bus Voltage Reference (U.000), and DC bus overvoltage error might be detected.
When an error occurred, the REV Current Limit cannot be set until the error has been reset.
Set the FWD current value (flowing in the direction to power running) to be limited as a ratio (%) of the Rated
Current (F.002). What is to be limited is the current value flowing by the PWM switching. It is impossible to
limit the current flowing through diodes.
When the set value of the FWD Current Limit is too small, the DC bus voltage might not go up to the set
value of the DC Bus Voltage Reference (U.000).
If the 8720MC-RPS Regenerative Power Supply operates in the power regeneration mode only, set this
parameter to 0%. The DC bus voltage to start power regeneration is the set value of the DC Bus Voltage
Reference (U.000).
When an error occurred, the FWD Current Limit cannot be set until the error has been reset.
U.000 DC Bus Voltage Reference
This parameter sets the
DC bus voltage reference
value. The 8720MC-RPS
Regenerative Power
Supply controls to maintain
the DC bus voltage at the
set value. Parameter Range: 275 to 750 V
Default Setting: 700 V
Parameter Type: Configurable only when the unit is normal
Refer also to Parameters: U.001 FWD Current Limit
U.002 REV Current Limit
F.005 Voltage Control Proportional Gain
F.007 Bus Overvoltage Detection Level
F.008 Bus Low Voltage Detection Level
Set the desired DC bus voltage (V) to this parameter. When the actual DC bus voltage is lower than the set
value, current flows to the direction of power running, resulting in increase of voltage. On the contrary, if the
actual DC bus voltage is higher than the set value, current flows to the regenerative direction, and the
voltage will drop. But when the current limits (U.001 and U.002) are set to low values, the DC bus voltage
might fluctuate because the current to be used for controlling the DC bus voltage is limited.
When the DC bus voltage is set too low, control will become impossible, and the DC bus voltage will swing
widely. Set the DC bus voltage to a value equal to or higher than the peak value of AC input power voltage
plus 30 V.
When regenerated power enters rapidly due to rapid deceleration of load equipment or other reasons, the
DC bus voltage might go up instantaneously. To prevent such rapid change of the DC bus voltage, adjust
the Voltage Control Proportional Gain (F.005).
If the difference between the set values of the DC Bus Voltage Reference and the Bus Overvoltage Detection
Level (F.007) is small, bus overvoltage fault may be caused.
When a fault occurred, the DC Bus Voltage Reference cannot be set until the fault has been reset.
U.001 FWD Current Limit
This parameter limits
current flowing from the AC
input power to the
8720MC-RPS
Regenerative Power
Supply during operation. Parameter Range: 0 to 150%
Default Setting: 150%
Parameter Type: Configurable only when the unit is normal
Refer also to Parameters: U.000 DC Bus Voltage Reference
U.002 REV Side Current Limit
F.002 Rated Current
7-4 Parameters