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"900W Lainey Schmidt digital power system", what is it and how does it work?
- Thread starter Bobnova
- Start date
- Joined
- Sep 15, 2007
- Location
- Small town Emlenton, PA
Was developed in a CW factory. You did see the movie 'Captain America'? It was part of the evil red guy stuff, right next to the blue glowy stuff from the glowy blue cube. You can't miss it in slow mo'.
The CW conglomerate took control of it back in the early 50's. Dirk Pitt has been fighting them for years. Great fiction book series, and it's real. Great reading. Start with The Raise the Titanic book. Sorry, he hasn't had to fight the CW folks yet, 20 years later. Still more fun than this issue.
All I know, more like one person on a mission to make all fans run in a silly way with no reason methinks. I learned it on the Internets. Thanks Al Gore!
The CW conglomerate took control of it back in the early 50's. Dirk Pitt has been fighting them for years. Great fiction book series, and it's real. Great reading. Start with The Raise the Titanic book. Sorry, he hasn't had to fight the CW folks yet, 20 years later. Still more fun than this issue.
All I know, more like one person on a mission to make all fans run in a silly way with no reason methinks. I learned it on the Internets. Thanks Al Gore!
OP
- Joined
- May 10, 2009
- Thread Starter
- #3
Whatever you're smoking, I want some
That said, the Dirk Pitt books are excellent.
The first dozen at least. More recent ones I liked less, the old ones are awesome.
- Joined
- Apr 1, 2010
- Location
- Wakefield, QC
Ask Bobnova, he's our resident power thingy 'n stuff expert. If he doesn't know, nobody knows.
Oh wait, you're....
OP
- Joined
- May 10, 2009
- Thread Starter
- #5
Exactly.
On a related note, the "120mm Delta fan with Cindy Wu sensorless DSP drive" is a standard Delta fan: http://www.delta-fan.com/Technology/ThreePhaseMotor.htm
There're still sensors of some sort, too.
I could call my car's alternator a "three phase generator with integrated rectification and load-aware predictive digital regulation", but it's still just an alternator
On a related note, the "120mm Delta fan with Cindy Wu sensorless DSP drive" is a standard Delta fan: http://www.delta-fan.com/Technology/ThreePhaseMotor.htm
There're still sensors of some sort, too.
I could call my car's alternator a "three phase generator with integrated rectification and load-aware predictive digital regulation", but it's still just an alternator
- Joined
- Nov 10, 2005
I found this: http://priuschat.com/threads/proud-owner-of-a-hybrid-pc.109768/
With this in the description:
Power system: 42A front end converter, 60A battery backup DC/DC converter, 30A battery charger, "Lainey Schmidt" digital power management controller.
I'm wondering if it is a battery backup system designed by a guy this person is friends with named Lainey Schmidt.
With this in the description:
Power system: 42A front end converter, 60A battery backup DC/DC converter, 30A battery charger, "Lainey Schmidt" digital power management controller.
I'm wondering if it is a battery backup system designed by a guy this person is friends with named Lainey Schmidt.
- Joined
- Nov 10, 2005
Maybe join the Gentoo or Prius forums and ask him?
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- Nov 10, 2005
OP
- Joined
- May 10, 2009
- Thread Starter
- #12
That'd be the guy getting called out.
He's the only one to mention the name/concept anywhere.
- Joined
- Jun 28, 2012
I thought he might have changed his sig because of this. Never mind my earlier post.
- Joined
- Mar 1, 2013
The term "sensorless drive" (apart from open loop V/Hz control) is actually a misnomer since the inverter has voltage and current sensors. (Technically, the motor itself is working as a sensor.) What they actually mean is that the inverter doesn't use a resolver, but instead senses the back EMF coming off the motor to synthesize the waveforms. Cindy Wu is a DSP algorithm tuned specially for the quirks of small, high speed fan motors. (BTW, not all Delta fans have Cindy Wu technology.)
On to the "Lainey Schmidt digital power system", that's actually a custom power system I designed for my PC. I'll start with the "Lainey Schmidt" part, the controller:
There's a PIC that runs the Lainey Schmidt firmware (under NDA, so no posting the source), some opamps to condition signals, and a few other bits like a few comparators to handle fault protection and power balance. There are 3 LEDs that accent the Intel sticker on the 12V rail cap and a USB link to the host PC. The most interesting feature is that the voltages and currents can be monitored through software (currently a few Python scripts) and some aspects of operation can be controlled through software.
Here's the Front End Converter, or what is a PSU in a traditional design:
It's pretty much just a heavily modified 550W ATX PSU. Most notable is that the PFC was bypassed to increase efficiency. (The input caps I added are 1200uF, 200V.) It's strictly for home use so PFC is a waste of efficiency. There's also a high voltage resistor (actually a string of several in series) to allow the controller to sense the input voltage, a relay to bypass the NTCs once precharge is complete, a current sensor to allow measurement of the output current, and a logic signal the controller can use to force the fan to run full speed above a certain output current.
Here's the battery charger module:
It's a modified 350W rackmount server PSU. The PFC was bypassed as well, though not entirely.
Here's the DC/DC converter:
It uses a very unusual topology to enhance efficiency, basically a mix of a current doubled push pull and a buck converter. Note that it's actually designed for more than just 60A. I just have it fused for 60A since that's all I need.
Note there are two power paths, so the combined power rating of the system is 900W. Above about 400W (which is never reached with the hardware I currently use), the controller starts commanding the DC/DC to pull some current from the battery (a common 12V deep cycle battery), which the charger immediately replenishes. It can also shift the power balance entirely to the battery (and disable the charger) in order to test it or to use alternative energy being pushed onto the bus.
Initially I had an Atom system in the same case, but since it got in the way of tweaking the main machine, I have since moved it into its own case with a (much) smaller version of the Lainey Schmidt power system.
It uses a bidirectional DC/DC converter rather than a dedicated charger module.
- Joined
- Sep 15, 2007
- Location
- Small town Emlenton, PA
Neat. So you talk about NDA and other magic (neat stuff) but it does NOTHING for the general populace or make one bit of diff, or actually makes people search for crazy stuff. Your CW stuff was designed by you and you must relentlessly try to get it on CNN.. Better yet. Fox news.
I see your drive. "I invented this, I will relentlessly promote it till bought out by a major company."
Okay. We's can filter out this now. Thanks.
Thankfully now we know.
And your EE skills are amazing! Best of luck for your future, you got smarts/schooling wayyy above me. But stop the CW crazy k? A basic guy needs nothing like that.
I see your drive. "I invented this, I will relentlessly promote it till bought out by a major company."
Okay. We's can filter out this now. Thanks.
Thankfully now we know.
And your EE skills are amazing! Best of luck for your future, you got smarts/schooling wayyy above me. But stop the CW crazy k? A basic guy needs nothing like that.
- Joined
- Jul 29, 2011
- Location
- Buenos Aires, Argentina
I can read more chinese that I can understand all that
OP
- Joined
- May 10, 2009
- Thread Starter
- #17
Thanks! I've been wanting to see the guts for some time now. What'd you do about 5v/3.3v in the PSU? It doesn't look to be a DC-DC unit is why I ask, so that's a hell of a crossload
Who's Schmidt?
You're the only one I can find calling the fan thing (which Nidec uses, too) sensorless (or, for that matter, cindy wu), the rest of 'em seem to just call it three phase.
Who's Schmidt?
You're the only one I can find calling the fan thing (which Nidec uses, too) sensorless (or, for that matter, cindy wu), the rest of 'em seem to just call it three phase.
- Joined
- Mar 1, 2013
3 phase doesn't have to be "sensorless", permanent magnet, or DSP. For that matter, Cindy Wu can be applied to 2 phase (AKA "split phase", sometimes incorrectly called "single phase") synchronous motors as well. Sanyo fans (at least the variable speed versions) and the original ECM Nidec fans (not to be confused with the newer ones that use a Cindy Wu equivalent) are 3 phase as well but they do have resolvers and no DSP. Some Sanyo and YS Tech fans have a circuit inside the control chip that effectively advances the phase, but it does so in an analog manner. It basically just adds some signal from the next resolver phase at high speed. Look at a phasor diagram and you'll understand how it works. Cindy Wu (or any sensorless drive) works in a similar manner, except the voltage and current readings coming back from the motor are digitized and DSP is done to extract the rotor position and synthesize the drive waveforms. The phase advance and whatnot are all done digitally.
Another sensorless drive I understand pretty well is the Shannon Liu quadrature drive, but that's only for induction motors used in reciprocating refrigeration compressors. It actually extracts the rotor speed by doing some rather involved filtering, downconversion, and FFTs, exploiting the torque ripple of a reciprocating compressor. I have no idea if it would work on a rotary compressor, but I'm pretty sure it won't work at all on a scroll compressor or a fan since those have basically no torque ripple.
The 5V and 3.3V buck modules are on the other side of the 12V cap, they're TI modules. They're very efficient, compact, and robust. For a one off, no need to waste time designing those when great off the shelf modules exist. The 12V DC/DC I had to build since I could not find any reasonably priced off the shelf unit.
BTW, I specialize in power electronics (though I do plenty of other stuff) which is why I'm really into that stuff. My latest project is building a hybrid air conditioner that also works as a water heater.
Another sensorless drive I understand pretty well is the Shannon Liu quadrature drive, but that's only for induction motors used in reciprocating refrigeration compressors. It actually extracts the rotor speed by doing some rather involved filtering, downconversion, and FFTs, exploiting the torque ripple of a reciprocating compressor. I have no idea if it would work on a rotary compressor, but I'm pretty sure it won't work at all on a scroll compressor or a fan since those have basically no torque ripple.
The 5V and 3.3V buck modules are on the other side of the 12V cap, they're TI modules. They're very efficient, compact, and robust. For a one off, no need to waste time designing those when great off the shelf modules exist. The 12V DC/DC I had to build since I could not find any reasonably priced off the shelf unit.
BTW, I specialize in power electronics (though I do plenty of other stuff) which is why I'm really into that stuff. My latest project is building a hybrid air conditioner that also works as a water heater.
- Joined
- Mar 1, 2013
I removed the original 5V and 3.3V circuits and reworked the feedback accordingly. In the space that's left over, I added some more local capacitance to the 12V rail.
I'm under the impression that split phase or "single phase" is just a way to refer to an asymmetrical 2 phase motor. I don't see any good reason to make an inverter fan asymmetrical since that would increase the torque ripple from the motor. (3 phase and 2 phase are inherently balanced as long as the phases are equal.) It makes sense with direct off line induction motors since to make the two equal would require a much larger and more expensive capacitor. The Shannon Liu drive is designed for asymmetrical motors because that's what is inside common refrigeration compressors. The main barrier to common use of inverters in small A/C and refrigeration units is the cost of custom engineering a compressor, so designing an inverter that works with a common "single phase" unit means a lot. Even more so if it means that existing equipment could be retrofitted.
I'm under the impression that split phase or "single phase" is just a way to refer to an asymmetrical 2 phase motor. I don't see any good reason to make an inverter fan asymmetrical since that would increase the torque ripple from the motor. (3 phase and 2 phase are inherently balanced as long as the phases are equal.) It makes sense with direct off line induction motors since to make the two equal would require a much larger and more expensive capacitor. The Shannon Liu drive is designed for asymmetrical motors because that's what is inside common refrigeration compressors. The main barrier to common use of inverters in small A/C and refrigeration units is the cost of custom engineering a compressor, so designing an inverter that works with a common "single phase" unit means a lot. Even more so if it means that existing equipment could be retrofitted.
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