Re: [Emc-users] BLDC Comp
On 11/26/2014 08:51 AM, andy pugh wrote: > On 26 November 2014 at 16:38, Kirk Wallace > wrote: >> is there an option that tells bldc to output the pwm >> directly? > > No. > > I did consider adding a base-thread function that did phase-locked PWM > but decided that the frequency would tend to be impractically low. > > The Mesa cards have a 3-phase PWM module which is ideal, though. > I'm thinking more in terms of what I can do using my parts bins and junk pile. I have an IRAMS on hand, and HAL. I just need to fill in the bits in between. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751&iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] BLDC Comp
On 26 November 2014 at 16:38, Kirk Wallace wrote: > is there an option that tells bldc to output the pwm > directly? No. I did consider adding a base-thread function that did phase-locked PWM but decided that the frequency would tend to be impractically low. The Mesa cards have a 3-phase PWM module which is ideal, though. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751&iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] bldc comp
On 17 January 2011 05:20, Kirk Wallace wrote: > I'm a little confused about the bldc comps. My study of bldc so far > indicates that the top and bottom of three half-bridges need to to be > controlled, so I though the comps would need six outputs instead of the > three (3 digital top, 3 PWM bottom). What am I missing? The currently-released bldc_hall and the half-released bldc_sine are aimed specifically at controlling the Mesa card three-phase PWM generator. The input is three float amplitudes, the output is 6 bit-level PWM signals. Except in the case of the 7i39 where the output is three bit-level PWM signals and on-board cleverness does the rest. The not-yet-released bldc (no suffix) component provides the output as three or six float or bit signals for either 6-step (trapezoidal) or sinusoidal drive. It does not (as yet) output any PWM signals directly, though that is something I have considered adding. With trapezoidal drive there are no adjacent steps where the high and low side driver states both change, so there is no danger of shoot-through with non-synchronised PWM signals, so in 6-step mode you could use ordinary pwmgens on the low-side drivers enabled from the bldc comp in hTB6 (hall input, 6 bit outputs, forced trapezoidal) or qBT6 (encoder input, 6 bit outputs, forced trapezoidal) modes. -- atp "Torque wrenches are for the obedience of fools and the guidance of wise men" -- Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] bldc comp
Erik Christiansen wrote: > But with a little dead-time between one being turned off and the other > on. So H-bridge drivers with hardware dead-time would be needed where > only three signals are provided. (AIUI) > You can't drive a 3-phase motor with only high and low drive in six step mode. It needs one bridge to be open-circuit. If you are driving it with a PWM sinewave scheme, then you could drive with only 3 wires. This requires the PWM amplitude relationships to change gradually as the motor rotates, so the bldc component needs to know absolute rotor position. This is the tricky part, until the encoder passes the index mark, or you use the Hall signals, you don't really know the absolute rotor position. Jon -- Protect Your Site and Customers from Malware Attacks Learn about various malware tactics and how to avoid them. Understand malware threats, the impact they can have on your business, and how you can protect your company and customers by using code signing. http://p.sf.net/sfu/oracle-sfdevnl ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] bldc comp
Kirk Wallace wrote: > I'm a little confused about the bldc comps. My study of bldc so far > indicates that the top and bottom of three half-bridges need to to be > controlled, so I though the comps would need six outputs instead of the > three (3 digital top, 3 PWM bottom). What am I missing? > There are a couple ways to control a 3-phase motor. The classic six-step scheme, which I use in my brushless servo amps, have a bridge high, a bridge low, and a bridge set to open circuit. So, that does require six wires. It is also possible to drive a motor in PWM sinewave mode, where all 3 bridges are active all the time. If the power stage can control the deadtime between high side and low side transistors, then you would only need 3 signals to control it. Jon -- Protect Your Site and Customers from Malware Attacks Learn about various malware tactics and how to avoid them. Understand malware threats, the impact they can have on your business, and how you can protect your company and customers by using code signing. http://p.sf.net/sfu/oracle-sfdevnl ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] bldc comp
On Sun, Jan 16, 2011 at 09:35:53PM -0800, Kirk Wallace wrote: > On Sun, 2011-01-16 at 21:20 -0800, Kirk Wallace wrote: > > I'm a little confused about the bldc comps. My study of bldc so far > > indicates that the top and bottom of three half-bridges need to to be > > controlled, so I though the comps would need six outputs instead of the > > three (3 digital top, 3 PWM bottom). What am I missing? > > Oops. I think I got it now. The bottoms are the ones complement of the > top. But with a little dead-time between one being turned off and the other on. So H-bridge drivers with hardware dead-time would be needed where only three signals are provided. (AIUI) Erik -- Protect Your Site and Customers from Malware Attacks Learn about various malware tactics and how to avoid them. Understand malware threats, the impact they can have on your business, and how you can protect your company and customers by using code signing. http://p.sf.net/sfu/oracle-sfdevnl ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] bldc comp
On Sun, 2011-01-16 at 21:20 -0800, Kirk Wallace wrote: > I'm a little confused about the bldc comps. My study of bldc so far > indicates that the top and bottom of three half-bridges need to to be > controlled, so I though the comps would need six outputs instead of the > three (3 digital top, 3 PWM bottom). What am I missing? Oops. I think I got it now. The bottoms are the ones complement of the top. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA -- Protect Your Site and Customers from Malware Attacks Learn about various malware tactics and how to avoid them. Understand malware threats, the impact they can have on your business, and how you can protect your company and customers by using code signing. http://p.sf.net/sfu/oracle-sfdevnl ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
