I don't think you can count on that, long term. I think you're going to need something to servo the voltage to zero.
That was my point. They really don't tell you what's going on. A few years ago, I wanted to DC couple an audio amp but couldn't get them (any of the manufacturers) to fork over the designs. We buy tons of these things but none were interested in showing us the details.
I was wondering that, RC the transformer drive & feed back with greater gain. Trouble is if the load ever has a rectified component, your amp is toast. There's a reason these kinda things are usually done with valves.
NT
PM alternators often drive shunt regulators, triacs or mosfets. We have to tolerate that.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
There were not that many made before JdL got taped by the FBI drooling over the prospect of a massive cocaine deal.
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Some folk may want to test with varying f to their 50Hz equipment, so lower may be better.
so many load problems can occur. There's still a reason people use valves.
NT
How do you intend to simulate the voltage spike when they suddenly reduce load?
NT
I'm wondering how you plan to do that with a toroidal, dc on the 2ndary having the same effect on the core as dc on the primary.
NT
A bit of our simulated inductance will be a real inductor. It can do the fast stuff, and our DSP loop can take over behind that.
It's similar to making a super-wideband inductor by making a series string of little and big inductors. People do that in bias tees and such.
The real-life load on the alternator will probably be shunt regulator, bridge rectifier, capacitor, so really fast spikes probably wouldn't matter much.
We're trying to get them to lend us an alternator. We could spin that somehow and see how it behaves.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
e load?
e load?
I'd think you'd need that to determine L, C etc.
Your app may have that load, but if you make it do under 50Hz it's going to get used for other tasks. Valves are inherently sledgehammerproof, as long as you add a spark gap. Many EEs have failed to achieve that with silicon. Dropping a heavy load on a shaker table could produce interesting 'signals '.
NT
The output LC LFPs are outside of any feedback loops, so the LPF filter inductor DC resistances are in series with the load DC resistances, thus limiting the DC current.
There appears to be a cat wandering about under the engine. Surely that's a safety fail?
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If the transformer primary is center-tapped you could watch the tap walking away from midpoint to trap imbalance but it seems a kind of round-about way. Just another idea tossed into the cook-pot!
piglet
An alternator is a current source, non-ideal due to the gap and other physical constraints, but essentially it is a current source. Jim T. explanind this here several years ago and it stuck with me.
After actualy thinking about how an alternator works, I could see that it could only ever be a current source. consider what drive you'd need if you were to replace the rotor with a sationary core and wanted the same output waveforms.
Why not start with a current source driving the primary of the transformer and simulate extra the leakage inductance caused by the gap.
control current in the fast inner loop. control voltage in the slow outer loop.
-- When I tried casting out nines I made a hash of it.
Have you seen these? The THD, IMD and noise specs are quite good:
Right, they add to the output DCR loop. I do want to keep them small, ideally surface mount and low DCR. The TI chip in mono mode wants 4 inductors with pairs essentially in parallel. The 4 inductors might add 10 mohms or so to the loop.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
I'm thinking we could just chuck it in one of our milling machines and spin it up. That guy did an awful lot of machining. And talking.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
The class D amps are inherently low impedance out. We's drive each amp from an FPGA and a DAC, to synthesize our sine waves. We'd sense final (after the transformer) voltage and current, digitize, and stuff that back into the FPGA. Then we can synthesize complex output impedance, anything from a voltage source to an inductive current source.
Should be fun to Spice.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
be
er
om
ng
but
educe load?
sure, when you don't have to a deal with part from a 60's fighter jet and keep it in a state that it can go back on the airplane you have a bit more leeway
And that cat was very distracting.
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