How hard is it to drive a 3-ph brushless motor?
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From: Jack on 9 Dec 2009 09:27 On 9 Dic, 14:47, z...(a)ds1.com (Peter) wrote: > Brushless motors are the way to go and there are ones with built-in > controllers which take a 0-10V control voltage, plus a logic level to > set the direction. > > The 2232BX4SChttp://www.micromo.com/servlet/com.itmr.waw.servlet.Anzeige?fremdaufr... > is one a number; other such as this onehttp://www.mclennan.co.uk/datasheets/european/brushlessdata/brushless... > are too big in diameter to fit into the space I have. > > But nobody does a suitable assembly which is short enough. To get the > max length I have to go to a bare brushless motor (no controller) and > mount the controller separately. check faulhaber.com or maxonmotor.com They have little motors and little controllers too. But they are not cheap. Bye Jack
From: Joerg on 9 Dec 2009 11:29 Peter wrote: > Tim Wescott <tim(a)seemywebsite.com> wrote: > >> Yes there are single chip solutions, but I was not happy with the one >> that I was involved with -- it came on the recommendation of a vendor, >> would have worked very well for the application for which it was >> designed, worked like _crap_ for us, and we ended up rolling our own >> controller almost a year behind schedule. > > Well, an hour or two's of googling later :) I found what looks just > the thing > > http://www.datasheetdir.com/ECN30206+Brushless-DC-Motor-Drivers > > This seems to do the lot - except that the control voltage seems to > control the % pulse width 0-100%. There is no feedback control of > motor speed. > x----------x The FB would have to be a uC or something. If you are concerned about motor run-away you could monitor one of the bridge outputs with a timer circuitry and let it go off if it exceeds a certain frequency. Then use that to cut power. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joerg on 9 Dec 2009 11:59 Peter wrote: > Joerg <invalid(a)invalid.invalid> wrote: > >> Peter wrote: >>> Tim Wescott <tim(a)seemywebsite.com> wrote: >>> >>>> Yes there are single chip solutions, but I was not happy with the one >>>> that I was involved with -- it came on the recommendation of a vendor, >>>> would have worked very well for the application for which it was >>>> designed, worked like _crap_ for us, and we ended up rolling our own >>>> controller almost a year behind schedule. >>> Well, an hour or two's of googling later :) I found what looks just >>> the thing >>> >>> http://www.datasheetdir.com/ECN30206+Brushless-DC-Motor-Drivers >>> >>> This seems to do the lot - except that the control voltage seems to >>> control the % pulse width 0-100%. There is no feedback control of >>> motor speed. >>> x----------x >> >> The FB would have to be a uC or something. If you are concerned about >> motor run-away you could monitor one of the bridge outputs with a timer >> circuitry and let it go off if it exceeds a certain frequency. Then use >> that to cut power. > > I think one could implement feedback easily enough. This chip has what > looks like a variable pulse rate "tachometer" output which is derived > from the Hall sensors directly. Converting this F-to-V would yield a > voltage proportional to actual RPM, and an op-amp comparator with -ve > feedback would adjust the input voltage to the controller chip > appropriately. > Depends on the load and timing requirements whether you need more fancy loop characteristics like PI or PID. > What I don't see is how one can reverse the motor with this chip. I > need -10V to +10V to give me direction/speed control. Presumably it > could be implemented by reversing two of the phases (and swapping over > the appropriate Hall sensors too) but that is a bizzare solution... > Yeah, that's odd, it only has a direction indicator output. That doesn't make a whole lot of sense. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joerg on 9 Dec 2009 12:03 Peter wrote: > This one is better > > http://www.lsicsi.com/pdfs/Data_Sheets/LS7560N_LS7561N.pdf > > Bidirectional, on-chip closed loop control, but needs external power > semis (no big deal). And it has the desired F/R input pin for direction reversal. Cool. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Tim Wescott on 9 Dec 2009 12:12
On Wed, 09 Dec 2009 16:37:32 +0000, Peter wrote: > Joerg <invalid(a)invalid.invalid> wrote: > >>Peter wrote: >>> Tim Wescott <tim(a)seemywebsite.com> wrote: >>> >>>> Yes there are single chip solutions, but I was not happy with the one >>>> that I was involved with -- it came on the recommendation of a >>>> vendor, would have worked very well for the application for which it >>>> was designed, worked like _crap_ for us, and we ended up rolling our >>>> own controller almost a year behind schedule. >>> >>> Well, an hour or two's of googling later :) I found what looks just >>> the thing >>> >>> http://www.datasheetdir.com/ECN30206+Brushless-DC-Motor-Drivers >>> >>> This seems to do the lot - except that the control voltage seems to >>> control the % pulse width 0-100%. There is no feedback control of >>> motor speed. >>> x----------x >> >> >>The FB would have to be a uC or something. If you are concerned about >>motor run-away you could monitor one of the bridge outputs with a timer >>circuitry and let it go off if it exceeds a certain frequency. Then use >>that to cut power. > > I think one could implement feedback easily enough. This chip has what > looks like a variable pulse rate "tachometer" output which is derived > from the Hall sensors directly. Converting this F-to-V would yield a > voltage proportional to actual RPM, and an op-amp comparator with -ve > feedback would adjust the input voltage to the controller chip > appropriately. > > What I don't see is how one can reverse the motor with this chip. I need > -10V to +10V to give me direction/speed control. Presumably it could be > implemented by reversing two of the phases (and swapping over the > appropriate Hall sensors too) but that is a bizzare solution... > > > x----------x HA HA HA HA HOO HOO HOO HOO HEE HEE HEE HEE HAW HAW HAW HAW But seriously -- if you're so dang experienced with working in software, why don't you want to do this with a microprocessor? Any pure-analog solution is going to be bigger, less flexible, and harder to get working than something built around a little bitty microcontroller that's made for driving 3-phase brushless motors once you add a bit of software. -- www.wescottdesign.com |