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    SMPS connection in three independent power source.

    I have a simple universal SMPS of 12V 1A. The problem is I have three independent AC power sources. One is the main power, the other one is the backup from an inverter and the other one is from a generator. Both phase lines provide 230VAC 50Hz.

    I want to power a microcontroller-based board that will use that 12V 1A SMPS. How can I use single SMPS and connect the three power sources across the SMPS?

    My condition is that the SMPS should not turn off if one or two of the power sources fails. Also, I cant use transformers as it will fluctuate if the input AC voltage drops significantly.

    Please note - I can modify the SMPS. It is based on power integration Driver IC.

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  2. #2
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    Re: SMPS connection in three independent power source.

    You can't combine the AC sources because of different voltages and phases but for a "simple universal SMPS" with low power capability like that I would use three SMPS, one on each AC source and combine their DC outputs. If you can live with a small (< 0.5V) drop you can simply use three diodes to combine their outputs.

    Brian.
    PLEASE - no friends requests or private emails, I simply don't have time to reply to them all.
    It's better to share your questions and answers on Edaboard so we can all benefit from each others experiences.



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  3. #3
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    Re: SMPS connection in three independent power source.

    You can rectify the 3 ac sources and then parallel them ( fuses..! ) as long as they don't share any common neutral on the AC side

    the PI chip based psu will happily run off the rectified 230Vac



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