Thank you guys for your recomendations. I've been trying and succeded (more or less) using oscillators like the ones from the PC switching power supplies, all of this based on DIY circuits found on the internet. The thing is that, since I'm planning to use LCNC to move the coil along the part, it would be pretty awesome if the system could handle the heater control part too.
Anyway, the real deal here is always how to have a clean square signal to fire the igbt's. I'm using dedicated IC's to turn on and of the transistors the one I used is TL494, but the matter is I always have little spikes at the output of the firing IC's, not at the oscillator's output. I couldn't attach a picture of the scope since is too big. Those spikes have a duration of about 1 uS, but I don't know if this is secure and I don't want to blow up the igbt's. In the picture there's only one of the signals, there's the other one 180ยบ phased that has the same problem. Again thanks a lot for your help, I decided to talk here about this because I know there's a lot of people here with way too much knowledge about power electronics, so If you can help me a little I would be very thankful! Leonardo. 2013/2/8 Peter C. Wallace <p...@mesanet.com> > On Fri, 8 Feb 2013, andy pugh wrote: > > > Date: Fri, 8 Feb 2013 09:00:58 +0200 > > From: andy pugh <bodge...@gmail.com> > > Reply-To: "Enhanced Machine Controller (EMC)" > > <emc-users@lists.sourceforge.net> > > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net > > > > Subject: Re: [Emc-users] Signal generator for induction heating > > > > On 8 February 2013 00:29, Sebastian Kuzminsky <s...@highlab.com> wrote: > > > >> Maybe a stepgen component in quadrature mode? That would let you easily > >> control the frequency of the output signal. > > > > That would be 90 degrees phase-shift I think, so not quite right. > > > > siggen might be the way to go. I think there are bridge control chips > > that handle the dead-time in hardware, and that might be a more > > reliable approach. > > > > I think that the three-phase PWMgen on Mesa cards has complementary > > signals, with deadband, that might be worth putting an oscilloscope > > on. > > > > -- > > atp > > If you can't fix it, you don't own it. > > http://www.ifixit.com/Manifesto > > > > This sounds like an ideal application for an Arduino (or cheaper > microprocessor) with an _isolated_ serial link to set the parameters. Many > little Micros have PWM hardware that will generate non-overlapping push > pull > drive though it may be harder to find one that can adjust the frequency and > duty cycle independently. > > > > > > > ------------------------------------------------------------------------------ > > Free Next-Gen Firewall Hardware Offer > > Buy your Sophos next-gen firewall before the end March 2013 > > and get the hardware for free! Learn more. > > http://p.sf.net/sfu/sophos-d2d-feb > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > Peter Wallace > Mesa Electronics > > (\__/) > (='.'=) This is Bunny. Copy and paste bunny into your > (")_(") signature to help him gain world domination. > > > > ------------------------------------------------------------------------------ > Free Next-Gen Firewall Hardware Offer > Buy your Sophos next-gen firewall before the end March 2013 > and get the hardware for free! Learn more. > http://p.sf.net/sfu/sophos-d2d-feb > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- *Leonardo Marsaglia*. ------------------------------------------------------------------------------ Free Next-Gen Firewall Hardware Offer Buy your Sophos next-gen firewall before the end March 2013 and get the hardware for free! Learn more. http://p.sf.net/sfu/sophos-d2d-feb _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
