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Parallel Operation with Different Power Supply Models

Posted on: June 22nd, 2021 by James

Parallel Operation with Different Power Supply Models
The same model of Kikusui DC power supplies can be connected in parallel. By connecting the signal cables, one unit is set as the master unit and it can control the other units. This operation is called as ‘master-slave parallel operation’.
Master-slave parallel operation is not available when connecting the different power supply models. To increase the output capacity with the different models, the parallel operation described below is recommended. To perform this operation, you need to set the voltage or current for each unit. The simultaneous power on/off is available with the external control. Below is the operation example.
1. Parallel Operation in Constant Voltage (CV)

Firstly, connect two different power supplies ‘PS1’ and ‘PS2’ in parallel as shown in Fig. 1.
1. Set the output voltage for PS1 and PS2. The output voltage value for PS1 should be approx.
0.3V higher than that of PS2.
2. Set the rated CC value for PS1 and PS2.
3. Turn the output on for both units. The voltage is outputted from PS1.
4. Gradually decrease the load resistance to increase the current. Since the setting voltage for PS1 is higher, the current flows from PS1 only. When the current exceeds the rated CC value for PS1, the output voltage changes to the setting voltage for PS2. Then, the current also flows from PS2. In this example, the total current (I1+I2) is: rated CC value for PS1 + PS2 (see Fig. 2).
During this operation, the output voltage changes with the current; e.g.) It changes 0.3V in the above example. If the same voltage is set for PS1 and PS2 (the voltage difference is 0V), the current becomes unstable that alternately flows from PS1 or PS2. The required voltage difference depends on the power supply type in use. Please set the appropriate voltage difference to keep the parallel operation stable.
2. Parallel Operation in Constant Current (CC)
To operate in CC mode, it is not necessary to set a specific voltage difference on each power supply. The constant current can flow from both PS1 and PS2.

Products Mentioned in this Application note:

Kikusui DC Power Supplies please see HERE