P
[email protected]
- Jan 1, 1970
- 0
I would like to find out something about the design of AC-DC and DC-AC
power convertor (power supply and inverter) designs. What I would like
to know is, for a given AC voltage, what would be the optimal DC voltage
to make the system most efficient (minimizing heat or other losses)?
What about optimal for making it cost the least to build?
What if the input AC voltage is to be different than the output AC
voltage? Would the optimal DC voltage have to track more to the input
AC or the output AC, or something in between?
I'm curious because I have been looking for, and have not found, a true
dual conversion (where it does AC to DC, then back to AC again) UPS that
can do 480 VAC input while providing 120 VAC output. I have seen some
that offer varying voltages, but when I dig in a little further I find
the fine print that says an extra cabinet is required for the mismatched
voltage version, which I believe will contain a transformer or three.
What I'd really rather have is a UPS system that does the AC to DC part
directly from the 480 VAC input, without a transformer, preferrably with
the ability to parallel 2 input units (if one is connected to a generator
then it could be effectively the transfer switch as well), parallels the
DC with batteries (controller needed here to manage the charge level I
presume), and then an inverter to produce AC back out, but at the 120
VAC level. I suspect inputting 3 phase would be better since even a
switching type power supply can find effective voltage levels almost all
the time on at least one of the phases. Outputting 1 phase would do the
job, but if the output is 3 phase WYE with 120 volt hot to neutral, that
does the job. 277 VAC would be an alternative where main power is in
the WYE configuration, since each leg is 277 volts relative to neutral.
power convertor (power supply and inverter) designs. What I would like
to know is, for a given AC voltage, what would be the optimal DC voltage
to make the system most efficient (minimizing heat or other losses)?
What about optimal for making it cost the least to build?
What if the input AC voltage is to be different than the output AC
voltage? Would the optimal DC voltage have to track more to the input
AC or the output AC, or something in between?
I'm curious because I have been looking for, and have not found, a true
dual conversion (where it does AC to DC, then back to AC again) UPS that
can do 480 VAC input while providing 120 VAC output. I have seen some
that offer varying voltages, but when I dig in a little further I find
the fine print that says an extra cabinet is required for the mismatched
voltage version, which I believe will contain a transformer or three.
What I'd really rather have is a UPS system that does the AC to DC part
directly from the 480 VAC input, without a transformer, preferrably with
the ability to parallel 2 input units (if one is connected to a generator
then it could be effectively the transfer switch as well), parallels the
DC with batteries (controller needed here to manage the charge level I
presume), and then an inverter to produce AC back out, but at the 120
VAC level. I suspect inputting 3 phase would be better since even a
switching type power supply can find effective voltage levels almost all
the time on at least one of the phases. Outputting 1 phase would do the
job, but if the output is 3 phase WYE with 120 volt hot to neutral, that
does the job. 277 VAC would be an alternative where main power is in
the WYE configuration, since each leg is 277 volts relative to neutral.
