Rockwell Automation Publication 750-AT006D-EN-P - January 2022
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Chapter 6 Active Front End Tuning
Regulators
Voltage Regulator Tuning
summarizes the parameter settings for the voltage regulator.
Voltage regulator tuning involves calculating PI controller gains for controlling the DC bus voltage, including the proportional gain K
P
and the
integral gain K
I
. Gain calculations are functions of the following parameters:
13:52 [Ext Bus Cap]
13:55 [Volt Reg Bw]
13:56 [Volt Reg Damping]
The internal capacitance is automatically included in the calculations. External capacitance may need to be entered if the DC bus observer is
not enabled. See
for more information. You can also set the proportional and integral gains directly by using the
following parameters:
13:57 [u Volt Reg Kp]
13:59 [u Volt Reg Ki]
Current Regulator Tuning
The proportional gain K
P
and the integral gain K
I
of the PI controllers regulating the d-axis and q-axis current components are calculated
using the current regulator tuning. These gains are calculated based on the inductance in the circuit that is connected to the power
converter, the desired bandwidth, and damping.
Inductance calculation
In most applications, the power converter is supplied by a source transformer or a generator. The inductance of the transformer/generator
is automatically calculated based on the kVA and the percentage impedance of the transformer/generator based on the corresponding
Table 25 - Voltage Control Loop Parameters
Parameter No. Parameter Name Description
13:52
[Ext Bus Cap]
External Bus
Capacitance
Enter a value for external bus capacitance. This should include:
• Bus capacitance of products outside of the local bus supply or integrated drive that share the common DC
bus.
• Capacitance of common bus inverters and DC input drives that share the common DC bus.
• Any additional capacitor modules added to the common DC bus.
13:54
[Volt Reg C/U Sel]
Volt Reg Calc/User
Select
Enter a value to select whether the DC bus voltage regulator uses calculated values or user-entered values
for proportional and integral gains.
Calculated values are determined by equations in the drive. These equations use value of 13:55 [Volt Reg BW],
13:56 [Volt Reg Damping], and 13:52 [Ext Bus Cap]. Parameter values are as follows.
• Calculated (0) - selects the calculated 'c' values.
• User Entered (1) – selects the user-entered 'u' values.
• LoadCalcData (2) – copies the calculated 'c' values into the parameter for the user-entered 'u' values. This
is useful for starting with the calculated values and then adjusting them.
– After performing the copy, this switch will revert to User Entered (1).
13:55
[Volt Reg BW]
Voltage Regulator
Bandwidth
Enter a value to set bandwidth of the DC Bus voltage regulator.
• This value is consumed by calculations that produce the calculated proportional and integral gains of the
regulator.
13:56
[Volt Reg Damping]
Voltage Regulator
Damping Factor
Enter a value to set damping of the DC Bus Voltage Regulator.
13:57
[u Volt Reg Kp]
Volt Reg Proportional
Gain—User Entered
Enter the value for the proportional gain of the current regulator that is used when 13:54 [Volt Reg C/U Sel] is
set to User Entered (1).
13:58
[c Volt Reg Kp]
Volt Reg Proportional
Gain—Calculated
Displays the value of the proportional gain of the current regulator that is used when 13:54 [Volt Reg C/U Sel]
is set to Calculated (0).
13:59
[u Volt Reg Ki]
Volt Reg Integral
Gain—User Entered
Enter the value for the integral gain of the Voltage Regulator that is used when 13:54 [Volt Reg C/U Sel] is set
to User Entered (1).
13:60
[c Volt Reg Ki]
Volt Reg Integral
Gain—Calculated
Displays the value of the integral gain of the Voltage Regulator that is used when 13:54 [Volt Reg C/U Sel] is
set to Calculated (0).