Talk:Universal Power Supply
"Rectifyers can be either passive schottky diode bridges, or active (IC-controlled) MOSFET H-bridges. Passive ones are cheaper, and ultimately more efficient for very high currents, while active ones are superior for low-medium-and-maybe-high currents yet more expensive. This design choice affects price, producability and simplicity."
This statement and the corresponding graph need better research. E.g. full-bridge Schottky diode rectifiers have a Vf_drop of at least 2*1V at high currents like those shown in the graph.
It should be noted that hard switched MOSFETS can be paralelled (and often are) without risk of thermal runaway because on resistance increases with temperature, so the active synchronous rectification option is scalable in ways that the passive diodes just aren't because their conduction voltage reduces with temperature. In addition, all MOSFETS are also Diodes, so when the are turned on in rectification mode (reverse conduction) you get the MOSFET 1mOhm characteristic in paralell with a high current, usualy low forward voltage diode with no extra expense giving the best of both worlds.--Alex Shure (talk) 02:17, 14 April 2013 (CEST)
General purpose or specific?
'A large range of power electronic devices is desirable within the infrastructure of communities. Having an individual power supply for each is redundant and expensive. A modular UPS construction kit is desirable as an analogue to the 'industrial-strength Lego' that we have already demonstrated for heavy mechanical hardware infrastructures.'
The list of different power uses and voltages for the Universal Power Supply begs a few questions. The standard AC supply system means that every device has its own unique custom power supply built in (or supplied with the device on a wire) that someone has spent a lot of time designing to be perfect for that device. starting from (eg) 12Vdc using the same electronics for supplying 19Vdc to a laptop (10A inductor, basic boost topology with syncronous MOSFET rectification, must maintain 19V at all times +-0.2V) as for supplying 19Vdc for a MIG welder (MIG welder likes variable voltage up to 39V and current sensitive drop in output voltage helps the arc to stabilise, could be done with 1:1:1:1 autotransformer in push-pull followed by inductor - all rated for 200A output operation, up to 600A input) doesn't make much sense, and what about when people want to do both at the same time? I know what is meant by 'redundant and expensive' but actualy, redundancy can be of great benefit when things fail, and even when they don't too. eg: we have 3 DC-AC inverters. 400W, 1000W, 3000W rated. we currently have bothe the 400W and the 3000W permanently installed, because the 3000W inverter (used for washing machine and electric chainsaw mostly) consumes 3A just to run its transformers, whereas the 400W one only needs 200mA for itself and someone needs to run their laptop for 5H a day (too far away for a 12V feed) because they're writing a book. The 3000W got blown by a close lightning strike and the only just superceded 1000W inverter came back to run the washing machine while I repaired the 3000W one. When the sky is too dark for a few days we revert to using direct DC-DC laptop chargers to reduce the load even further. In short, I cannot imagine a one-size-fits-all machine in this category. Please convince me.
in my opinion
I agree that a one-size fits all is not feasibly acheived. I think based on the ecology model though, they are looking for a heavy load inverter that could handle multiple inputs and outputs; akin to a whole house inverter system you might find at solar stores or RV suppliers would be my guess. My main question is: why not call it by its most common/accepted name? Its not an Universal Power Supply.. Its an Uninterruptable Power Supply. Its main purpose is to keep supplying electricity when main systems (electric company or whatnot) fail. Thats my main suggest.. call it by its proper name, and you'll likely see more hits and possibly more help with the project.