MUGL
Page 19 of 38
rev. 18 November 2009
9
Control scheme
The FVC converter has two control units, one for regulation and one for central
management, both are externally accessible and modifiable through the appropriate
programs:
•
Control and regulation unit by means of “GesPWM” software
•
Central management unit by means of “FVC Manager” software
10 Control and regulation unit
The converter is equipped with a sophisticated digital control system, which has to keep
the voltage and/or the current output constant regardless of load change and mains
variations.
The regulation is based on two PID algorithms in sequence and named:
“Inner loop” with feedback current taken at the output,
“Outer loop” with feedback voltage taken at the output.
The following figure shows the principle of operation
10.1 Control system block diagram
The control loops are pre-adjusted in production to have a good compromise
between speed and stability over most loads, in some cases it is necessary to change
some parameters for the following reasons
:
•
Oscillations due to a load too reactive
•
To enhance the generator dynamic performance
•
To adapt the generator to the load
PWM
Output
current
Output
voltage
Voltage
reference
+
+
-
-
Inner loop
Outer loop
REF
REF1
REF2