4 Series and Parallel
Operation
4.1 Series operation
¡
Series operation is available by connecting the outputs of two or
more power supplies as shown below. Output current in series
connection should be lower than the lowest rated current in each
unit.
Load
Load
Power
Supply
Power
Supply
Load
Power
Supply
Power
Supply
(a)
(b)
Fig. 4.1 Examples of series operation
4.2 Parallel operation
¿
TUNS300F/500F/700F
¡
Parallel operation is not possible.
¿
TUNS1200F
¡
Parallel operation is available by connecting the units as shown in
Fig.4.2. With this wiring, it is possible to adjust all output in module
by single potentiometer. When output voltage adjustment is not in
use, VTRM wiring, VR1 are not necessary.
¡
Constant current adjustment can be used, even in parallel opera-
tion. By changing the ITRM voltage of one power supply, constant
current adjustable for all power supplies. It is not necessary to
connect the ITRM terminals together.
¡
Total current should not exceed the value calculated by the follow-
ing equation, and total number of units should be no more than 9
pieces.
(Output current at parallel operation)
= (the rated current per unit) × (number of unit) × 0.9
¡
Please make sure that the wiring impedance of a load from each
power supply becomes even.
¡
Voltage drop from a power supply to the sensing point should be
less than 0.5V for stable control.
¡
If temperatures of aluminum base plates are different in the power
supply for parallel operation, the difference in output current be-
comes large. Design radiation to equalize plate temperatures by
attaching the same heat sinks.
¡
Connect the sensing line and the power line by one point after
connecting each power supply’s sensing pins(+S, -S).
¡
If the output current is less than 2% of the rated current, the output
voltage ripple will be large.
¡
When the input voltage is applied with remaining the voltage at
boost capacitor Cbc, startup time would be different for each
paralleled module. If all paralleled modules need to startup at the
same time, remote control function shall be used.
¡
Examples of connecting remote ON/OFF circuit during parallel op-
eration is shown in Fig.4.3.
Load
+
+
+
Co
Co
Co
VR1
FG
+
R
C1
F1
FG
AC IN
FG
TFR1
CY
C3
C2
+BC -BC
+S
Cbc
AC1
AC2
+VOUT
-VOUT
-VOUT
-VOUT
Noise
filter
FG
+
R
C1
F1
FG
FG
TFR1
CY
C3
C2
+BC -BC
+S
Cbc
AC1
AC2
+VOUT
Noise
filter
FG
+
R
C1
F1
FG
FG
TFR1
CY
C3
C2
+BC
+S
-S
-S
-S
CB
VTRM
CB
VTRM
CB
VTRM
Cbc
AC1
AC2
+VOUT
Noise
filter
-BC
Fig.4.2 Examples of parallel operation (TUNS1200F)
RC2
RC1
AUX
－
S
RC2
RC1
AUX
－
S
RC2
RC1
AUX
－
S
ON
OFF
POWER
Fig.4.3 Examples of connecting remote ON/OFF circuit during parallel operation
¡
Please refer to the application manuals for details of parallel op-
eration.
Application manual is on our web site.
¿
–P (TUNS700F)
¡
This option is for parallel operation.
¡
Sensing and adjustment of the output voltage are not possible at
the time of the use with this option.
¡
As variance of output current drew from each power supply is
maximum 10%, the total output current must not exceed the value
determined by the following equation.
(Output current in parallel operation)
=(the rated current per unit) × (number of unit) × 0.9
Total number of units should be no more than 5 pieces.
AC-DC Power Supplies Bus Converter.Power Module Type TUNS300F, TUNS500F, TUNS700F, TUNS1200F
Instruction Manual
TUNS-29
July 27, 2020
