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symmetrical SMPS

Hi,

I was thinking about a good power supply that combined stepdown with inverter functionality and thought that a SMPS could be run in reverse to function as an inverter if you replaced all the diodes with FET's and/or IGBT switches. B1, B2 and B3 are all H-bridge switches.

So for stepdown mode (left to right): B1 operates as a synchronous rectifier B2 operates as a switcher B3 operates as a synchronous rectifier

for inverter mode (right to left): B1 operates as a switcher (uses sine lookup table and PWM to generate 60Hz AC or other frequency) B2 operates as a synchronous rectifier B3 operates as a switcher

So would this work? I was going to build a PC clone SMPS anyway so I figured it would be good to have it work as an inverter if possible too! :)

cheers, Jamie

I hope this schematic looks ok! :)

B1 C1 ___ C2 B2 B3 C3 ___ C4 +-+------o---UUU---o-----+-+ T1

+-+-----o---UUU----o------. A A | L1 | A A -----. ,----- A A | L2 | | high volt ---+ | --- --- | +-- 5 )|( 1 --+ | --- --- '- low volt AC or DC ---(-+ --- --- +-)-- )|( --(-+ --- --- .- AC or DC A A | | A A -----' '----- A A | | | +-+------o---------o-----+-+ +-+-----o----------o------'

(created by AACircuit v1.28.4 beta 13/12/04

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Reply to
Jamie Morken
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B1 C1 ___ C2 B2 B3 C3 ___ C4 +-+------o---UUU---o-----+-+ T1

+-+-----o---UUU----o------. A A | L1 | A A -----. ,----- A A | L2 | | high volt ---+ | --- --- | +-- 5 )|( 1 --+ | ---

--- '- low volt AC or DC ---(-+ --- --- +-)-- )|( --(-+ ---

--- .- AC or DC A A | | A A -----' '----- A A | | | +-+------o---------o-----+-+

+-+-----o----------o------'

(created by AACircuit v1.28.4 beta 13/12/04

formatting link

Jamie Morken wrote:

Reply to
Jamie Morken

Bidirectional power transfer, through the same isolation transformer is much more difficult than you suggest, if you intend to maintain some kind of regulation. It's a long way from anything clone-ish.

There are few reasons why you'd want to pump low voltage energy back into line voltage levels for storage or transmission - it's usually much more efficient to use the low voltage energy to perform the low voltage tasks that were originally intended of the isolated converter outputs, directly.

"Everything runs off 120VAC" .......... is a pretty silly statement in electronics, where voltages less than 24VDC are usually much more easily employed when direct heating or hp-sized motors are not involved.

RL

Reply to
legg

Hi,

The application I was thinking of was a high current battery charger built into a scooter, which could also then be used as a portable

120VAC source using the scooter batteries.

cheers, Jamie

Reply to
Jamie Morken

Run your scooter electronics off the battery that's there. It's free and already got a charger.

RL

Reply to
legg

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