On Tue, 18 Jun 2013, propcoder wrote: > Date: Tue, 18 Jun 2013 22:57:18 +0300 > From: propcoder <marius.alks...@gmail.com> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: emc-users@lists.sourceforge.net > Subject: Re: [Emc-users] BLDC - not smooth rotation with hostmot2 and 3-phase > bridge > > > On 2013.06.18 15:59, Peter C. Wallace wrote: >> Maybe tha actual physical dead time is causing your torque ripple > What do you mean by "actual physical dead time" - electric (which I > described earlier) or physical some..? > >> IGBTs have a large on voltage (maybe 2V or so) which will add to non >> linearities. This and the larger dead time may be the cause of this. >> It could also be a wiring error. Do you have 3 'flat spots' per electrical >> phase rotation? (1/2 turn on a 4 pole motor) > This may be a point! I need to try with 48V PSU. > >>> By the way, what max voltage I can go with this setup when I use phase >>> current limiting? >> 600V IRAMs? maybe 450V assuming your isolation, bypassing, and deadtime are >> right. >>
Yes but you definately need good and fast current limiting > > I am asking about IRAM power voltage when driving these 48V motors. > Would it be possible to drive them from 320V? As I understand it is a > question of isolation and max current, which may be ok, or am I wrong? That is probably a mistake as a 48V motor inductance will be low enough that you will have large ripple currents running from 320V > >> >> This is possibly a BLDC setup error. You do need to limit the applied voltage >> in N mode via "initvalue" since current is only limited by winding >> resistance. > > I am testing various values (bldc.0.value in "n" mode and > bldc.0.initvalue in "qi" mode) - from 0.1 to 0.6. >> >> No idea unless their motor outputs such a voltage. Spin your motor >> and look at the generated voltage with a scope. > > Tried this - quite nice sine. > > > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Windows: > > Build for Windows Store. > > http://p.sf.net/sfu/windows-dev2dev > _______________________________________________ > 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. ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
