As shown in the diagram, I am trying to connect two power sources to load. The battery source is for emergency in the case of power outage of the wall source. I want the switching to be instantaneous with no interruption of power.

What is the best solution to this problem? Is there a board out there that I could use? There must be no interruption of power.

Thank you!

 

For no interruption of power, the typical UPS uses the inverter to power the load all the time, with the battery being continually charged by the main's power as well as supplying the inverter power.

 

That block is called a transfer switch.
If you don’t mind losing a hundred milliseconds or so, a simple DPDT relay will do.
If a faster transition is required, you require to use SCR or IGBT devices but still lose perhaps half a power cycle, 10 milliseconds in your case.

For truly uninterrupted power, you’ll do as Crutschow explained.

 

That block is called a transfer switch.
If you don’t mind losing a hundred milliseconds or so, a simple DPDT relay will do.
If a faster transition is required, you require to use SCR or IGBT devices but still lose perhaps half a power cycle, 10 milliseconds in your case.

For truly uninterrupted power, you’ll do as Crutschow explained.

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