micro-controlled IH
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From: Michael Robinson on 22 Apr 2010 10:20 the video: http://www.youtube.com/watch?v=vZlROIqG_RU A thread with a little more info: http://4hv.org/e107_plugins/forum/forum_viewtopic.php?85701 Curses. Now I have to learn how to use micros.
From: MooseFET on 22 Apr 2010 10:45 On Apr 22, 7:20 am, "Michael Robinson" <kellrobin...(a)yahoo.com> wrote: > the video: > > http://www.youtube.com/watch?v=vZlROIqG_RU > > A thread with a little more info: > > http://4hv.org/e107_plugins/forum/forum_viewtopic.php?85701 > > Curses. Now I have to learn how to use micros. You can do the same thing with a phase detector running the VCO. The phase shift between the voltage and current will bring you to the resonance point. If you want to use a micro, why not make the frequency with the micro instead of a VCO. 100KHz is within the reach of a micro. If you use an Silabs F120, you can get the frequency to within 0.1%.
From: Tim Williams on 22 Apr 2010 12:54 "MooseFET" <kensmith(a)rahul.net> wrote in message news:0f5d6d94-921c-4118-9939-5e3150fe82b3(a)t14g2000prm.googlegroups.com... > You can do the same thing with a phase detector running the VCO. Which is what I do. Adjusting phase allows one to adjust output power without having to also vary supply voltage. Locking it is trivial, but adjustment is handy. Some day I'll write a uC controlled version, maybe using an ATtiny at 20MHz or something. Keep analog interface as simple as possible, maybe not to the point of using the internal analog comparator for phase detection, but at least doing the phase detection internally would save a flip-flop and error amps. That'll eliminate a good 70% of circuit board area. The uC and gate drivers and GDT can occupy the remaining space. It'll be little more than a power transformer, handful of chips and the (still necessary) analog interface bits (comparators, transformers). Lots more surface mount parts means fewer holes to drill and even less used space. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms
From: Tim Wescott on 22 Apr 2010 13:01 MooseFET wrote: > On Apr 22, 7:20 am, "Michael Robinson" <kellrobin...(a)yahoo.com> wrote: >> the video: >> >> http://www.youtube.com/watch?v=vZlROIqG_RU >> >> A thread with a little more info: >> >> http://4hv.org/e107_plugins/forum/forum_viewtopic.php?85701 >> >> Curses. Now I have to learn how to use micros. > > You can do the same thing with a phase detector running the VCO. > The phase shift between the voltage and current will bring you > to the resonance point. If you want to use a micro, why not make > the frequency with the micro instead of a VCO. 100KHz is within > the reach of a micro. Depending on the micro you can do even better than that. And -- should you have any desire to do so -- you can throttle down the duty cycle as well. > If you use an Silabs F120, you can get the frequency to within > 0.1%. And others... This is certainly a task that -- in a product -- would likely be better done in a microprocessor. Whether it's better in a hobbyist/small run/home environment is debatable. The one driving factor in using a micro for control is that you can suddenly make major changes in your systems personality with minor or no changes to the hardware. Hm. That could be clearer, let me try it again: Yes!! Using a phase detector and VCO will work admirably well!! Snag a 4046 off the shelf (surely you have some of those), do some signal conditioning, and away you go. In extremis you may have to use a multiplier for a phase detector, which means you'll need a 90 degree shifted version of your VCO, but that's no biggie if it's digital (using a 4X clock it's easy to configure a J-K flip flop as a quadrature divide-by-four). OTOH, there's a _lot_ that you can do with micro. Assuming that you can wrap your brain around the necessary embedded development skills, there are huge swaths of the product development that'll go quicker with a micro. In fact, you'll have such flexibility, that one of your biggest pitfalls will become running feature creep, where you spend all your time programming in just one more thing, and never ever do anything useful with your device. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com
From: amdx on 22 Apr 2010 13:44
"Tim Wescott" <tim(a)seemywebsite.now> wrote in message news:JK6dndA70_uEHU3WnZ2dnUVZ_sOdnZ2d(a)web-ster.com... > MooseFET wrote: >> On Apr 22, 7:20 am, "Michael Robinson" <kellrobin...(a)yahoo.com> wrote: >>> the video: >>> >>> http://www.youtube.com/watch?v=vZlROIqG_RU >>> >>> A thread with a little more info: >>> >>> http://4hv.org/e107_plugins/forum/forum_viewtopic.php?85701 >>> >>> Curses. Now I have to learn how to use micros. >> >> You can do the same thing with a phase detector running the VCO. >> The phase shift between the voltage and current will bring you >> to the resonance point. If you want to use a micro, why not make >> the frequency with the micro instead of a VCO. 100KHz is within >> the reach of a micro. > > Depending on the micro you can do even better than that. And -- should > you have any desire to do so -- you can throttle down the duty cycle as > well. > >> If you use an Silabs F120, you can get the frequency to within >> 0.1%. Do you believe this 10,000 wattts? I don't see any water cooling of the inductor http://www.youtube.com/watch?v=-Aab9CBA9vk&feature=related It's cool though, I mean neat, though. Mike |