Parallel operation

Connecting more than one power supply device to a single load to share and supply output current. When the output of the power supply device is DC, the voltage must be equal. For AC, in addition to voltage, the frequency, phase, and waveform must match exactly. If the voltage or waveform differs, abnormal current may flow in the power supply device, leading to failure. Even if one of the power supply devices fails, power supply from the other device can continue without interruption, so this is often done to ensure power reliability.