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I'm looking for an efficient and fairly cost-effective way to boost the voltage of a center-tapped battery pack (+/-180V to +/-250V) to +/-350V. The output load is quite variable anywhere from 0.5A to 15A What's a good topology for this application?

Is a 3-phase converter like this a reasonable choice? Please also take a look at the orientation of the N-channel MOSFETs since I'm not 100% sure about that.

schematic

simulate this circuit – Schematic created using CircuitLab

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    \$\begingroup\$ With 1V drop on the diode it loses only 1/350 = about 0.3% efficiency... \$\endgroup\$
    – bobflux
    Commented Nov 14, 2021 at 0:08
  • \$\begingroup\$ It seems to be a 3 (or 6) interleaved boost converter. Yes, the horizontal MOSFET can be replaced by diodes. MOSFET drop voltage would be higher (?, especially high voltage devices ), and you need 6 more drivers ... It would be also interesting that the drivers have a common "gnd" (?), so changing the type of the lower MOSFETs. 3 drivers to "unlock" up and low MOSFET. \$\endgroup\$
    – Antonio51
    Commented Nov 14, 2021 at 8:41
  • \$\begingroup\$ Good point, those MOSFETs probably only make sense for higher currents/lower voltages. Edited the circuit. I think I'd prefer to keep all MOSFETs the same type and characteristics (and deal with the more complicated drivers). \$\endgroup\$
    – Cedric
    Commented Nov 14, 2021 at 9:09

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Probably not the best choice of MOSFET, here an example (for the positive upper part) of what you get with an interleaved boost converter with duty variable for control (not designed).

I have found also this note. Perhaps can also help : AN-1126

enter image description here

Added behavior with "load change" to see "performance" open loop ...

enter image description here

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  • \$\begingroup\$ Thanks. I've been playing around with the design in LTspice for a few hours. What software is that you're using? \$\endgroup\$
    – Cedric
    Commented Nov 14, 2021 at 22:18
  • \$\begingroup\$ microcap v12 spectrum-soft.com/index.shtm It would be also interesting doing a "test behavior" where duty cycle has a step (example from 0.3 to 0.35). \$\endgroup\$
    – Antonio51
    Commented Nov 16, 2021 at 16:47

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