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I am working on a three phase 110 VDC & 100 A SCR rectifier/battery charger. I'm not sure which one of the circuits in the image is better for filter and diodes. Please help me with these components placement in the circuit:

  1. reverse diode
  2. inductor, blocking diode, droppers (is better to place them in positive bus or negative bus?)
  3. resistor (it is for providing holding current for SCRs- is it necessary to have a current through dropper diodes (in no load condition) for keeping dropper diodes turned on?
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    \$\begingroup\$ In my opinion none of this is needed, except if you give a link/document where it shall be used and why. \$\endgroup\$
    – Marko Buršič
    Commented Oct 16, 2021 at 8:23
  • \$\begingroup\$ Looks like a mess. You need to start with a goal for output current supply, output voltage and ripple limit. Then work from the input voltage available to build toward your goal in a logical way. The schematic looks like you changed your mind multiple times about your design goal or your strategy to solve your design goal. \$\endgroup\$
    – GT Electronics
    Commented Oct 22, 2021 at 16:15
  • \$\begingroup\$ @GT Electronics this image shows only the power part of the system. the system contains a control unit (sensors and motherboard) \$\endgroup\$
    – Hassan V
    Commented Oct 24, 2021 at 20:06

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SCRs? Large inductors? Dropper diodes? Is this 1960?

No, this is 2021, and today we treat Lead-acid and Li-ion batteries as they should be treated: we charge them with a CCCV charger, using switchmode regulators.

So, in answer to your question: none of the three options are safe for your batteries. EDIT, based on new info from OP:

While our ancestors may have had to use such unsafe circuits to charge lead acid batteries, today we have safe options. You should use a safe CCCV charger.

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  • \$\begingroup\$ this charger actually has control unit(a pcb which contains an mcu and peripherals), battery and load current sensors, battery and load voltage sensors and gate trigger circuit for SCRs (which is connected to main mcu) .I coded an algorithm for constant current or constant voltage, boost mode, float mode and ... in C. this image shows only the power part of the charger. \$\endgroup\$
    – Hassan V
    Commented Oct 24, 2021 at 20:02
  • \$\begingroup\$ Good to know, good to know. Thanks. I still say that you're better off buying a ready-made switchmode battery charger and forget the SCR design. \$\endgroup\$
    – Davide Andrea
    Commented Oct 24, 2021 at 20:07

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