I am trying to power an Arduino for a DIY power quality/meter project. It has to work in scenarios without neutral (three-phase delta) so it can still work in case of neutral loss or for applications without neutral.
The goal is also to take advantage of the three phases for supply redundancy and has to work even with a two-phase fault.
My strategies so far are:
Use three step-down transformers in delta/delta arrangement, followed by a three-phase rectifier six-diode bridge and a smoothing capacitor, followed by a step-down regulator module to 12 V. Rock solid, but bulky.
Rectify first the three phases with a six-diode bridge, put a high voltage series capacitor after the bridge to remove DC bias, and feed it to an AC/DC power module that accepts a high RMS voltage. I found a module up to 500 V RMS. The problem here would be the frequency of the rectified wave would not be 50 but 300 Hz. That would derate the performance of the transformer in the module.
The second option is less bulky but with a lot of uncertainties. What would you choose? Are there other options you see? Required rated power is 10 W for the system (and for each individual component, since it has to work even with a two phase fault).