In a dc-dc transformer we mostly see a reservoir capacitor, that is charged by some control circuit and decharged by the application.
What about a reservoir inductance? I know there are problems with saturation, but OTOH it is easier to pump extra energy into the inductance because the delta E is the product of the extra current and the current already present.
Is this being used anywhere? Maybe there is a reason why not?
Groetjes Albert
-- This is the first day of the end of your life. It may not kill you, but it does make your weaker. If you can't beat them, too bad. albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst
That definition might fit a flyback converter and friends?
The transformation you're looking for, is: convert all series nodes to parallel branches and vice versa; swap capacitors and inductors; and swap voltages with currents.
Therefore the series reservoir inductor smooths current, just as the parallel reservoir capacitor smooths voltage.
Tim
-- Seven Transistor Labs, LLC Electrical Engineering Consultation and Design Website:
Draw a circuit and we'll discuss it.
-- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
Scaleability and static loss.
RL
Some ancient electronics used choke-input filters. Three-phase AC can be full-wave rectified into an inductive filter, which makes sense in some applications.
-- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
Cost primarily, I would imagine.
Most people like their power supplies to have a low output impedance across the working frequency range.
Switchers do usually store a lot of their energy in inductors.
-- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
I'm wondering what the ESR effects of using inductors for storage vs. a big ol' bank of electrolytics. I would have thought there'd be adverse consequences ripple-wise at the output, even under light loads?
As I recall, the issue was to smooth out the current pulses for a capacitor-input ripple filter. I think that The Radiotron Designers Handbook had a chapter on this.
Don't forget" swinging chokes".
Joe Gwinn
Flyback converter?
Jeroen Belleman
In olden times they sometimes used a common-mode choke and ran the device filament current through the other winding to reduce its size.
I remember seeing a patent on this technique from about 1925 but can't find it atm
I suppose big capacitors were expensive in olden times, so inductors made sense.
Tubes were expensive too, hence interstage transformers for voltage gain.
Someone could prowl Digikey and calculate joules/dollar for some inductors and caps.
Yes, by the megawatt, in aluminum refining by electrolysis. There's too much current for a single diode, so you parallel the diodes, and use inductive pass-through to keep the hottest one from hogging the current. The trick is, inductive energy storage works best in LOW impedance (high current, low voltage) circuitry, and doesn't like dI/dt (which can be huge in a clocked digital system), so only unregulated-volt/high-current applications seem appropriate.
The elusive room-temperature superconductor might change the breakeven points, sometime in the coming century.
The issue was mostly rectifier capability. That's why the 'current doubler' or hybridge circuit was developed during the reign of the mercury rectifier; only to be rediscovered in the times of commodity
100A processor supplies.For energy storage, I'd assumed the OP was interested in time scales greater than two cycles of the mains frequency.
RL
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Someone has found a superconductor that super-conducts up to 17 Celcius, w hich is almost room temperature. You have compress it quite hard to get sup er-conductivity - an appreciable proportion of the pressure at the earth's core, so it got demonstrated on a very small scale in a diamond anvil compr ession cell. You couldn't store much energy in that.
-- Bill Sloman, Sydney
It cannot be the energy store feeding the application circuit, because any attempt by the application to reduce its current draw abruptly would result in the input voltage going up.
Sylvia.
Tube rectifiers do not like high peak currents (limited emission, large voltage drop). Using LC or CLC input filters extended the conduction angle, hence reducing the peak current.
For inductive storage, the 'storing state' is a short circuit across its terminals.
RL
Many of our laser drivers use inductive energy storage.
-- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
Jabbut a laser is mostly a current consumer.
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