PROGRAMMING GUIDE
SINUS PENTA
407
/
486
46.5.
Example of Compensation of Voltage Drop in a Filter
Assume that a sinusoidal filter is installed between the Penta Drive and the motor. The drive output voltage is to be
adjusted to compensate for voltage drop caused by that filter. The following can be used as a feedback signal:
1) an analog input, connected to a signal proportional to RMS voltage, downstream of the filter, obtained by transforming
and rectifying one of the phases;
2) two analog inputs, connected to two signals obtained by transforming two of the phases, utilized by the system to
compute the RMS voltage value (see
M051a
).
46.5.1.
V
OLT AGE
D
ROP
C
OMPENSAT ION
–
F
EEDBACK FROM
S
INGLE
A
NALOG
I
NPUT
Assume that a 0-10V voltage signal proportional to RMS voltage downstream of the filter is available and that 50Vrms
correspond to 1V. This signal is linked to analog input
AIN1
. The rated motor voltage (
C019
) is assumed to be 400V.
Set the following in the PID CONFIGURATION MENU:
C285
Selection of PID Reference 1
9: V out
C288
Selection of PID Feedback 1
2: AIN1
C291
PID Operation
1: Normal
C294
PID Feedback
3: Add Voltage Output
Set the following in the INPUTS FOR REFERENCES MENU:
P055
Type of Reference for AIN1 Input
3: 0-10V
P057
Ref. Max. Value Limits for AIN1 Input
10.0V
Set the following in the PID PARAMETERS MENU:
P236
Max. PID Output
100.00%
P237
Min. PID Output
0.00%
P240
Proportional Coefficient Value
1.000
P242
Integral Time
Disabled
P245
PID Reference Min. Value
0.00%
P246
PID Reference Max. Value
125.00%
The selection criterion of parameters
P057
and
P246
is the following as per the hypothesis above: 10V for
AIN1
correspond to 500Vrms, i.e. 125% of the rated motor voltage set in
C019
.
The compensated output voltage will be as follows:
Vout = Vd + Vmot*PIDout, where:
Vd is the voltage that could be delivered without compensation,
Vmot is the rated motor voltage (
C019
),
PIDout is the PID output, given by (Vref - Vfbk)/Vmot.
