On Mon, 15 Jul 2013, propcoder wrote: > Date: Mon, 15 Jul 2013 21:13:41 +0300 > From: propcoder <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: [email protected] > Subject: [Emc-users] hm2 - pwmgen vs 3pwmgen for BLDCs > > I am thinking of my misfortune with IRAM IGBT module and BLDC motors. As > I wrote earlier - the motion and torque was not smooth.
Because of the longer dead time on IGBTs, you would need to pre-distort the sine waves (add the PWM width of the deadzone, basically a anti-deadzone) to get the smoothest motion. On the other hand if you have feedback working well, the dead zone crossings should have minimal impact on controlled motion. Consider that many systems dont use sine wave drive at all and do OK (+- some tics at commutation points) Motion without feedback (step motor mode) may well be lumpy at the sine wave zero crossings however, since the drive will remain 0 until the PWM width gets as big as the deadzone. > > Is there sense to try to commutate lower transistors just on-off and > higher ones with sine PWM? If so - can simple hm2 firmware with pwmgens > be used for that (instead of 3pwmgens, which do have A-value, B-value > and C-value input pins only)? > > Marius I dont actually think this will help > > > ------------------------------------------------------------------------------ > See everything from the browser to the database with AppDynamics > Get end-to-end visibility with application monitoring from AppDynamics > Isolate bottlenecks and diagnose root cause in seconds. > Start your free trial of AppDynamics Pro today! > http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > [email protected] > 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. ------------------------------------------------------------------------------ See everything from the browser to the database with AppDynamics Get end-to-end visibility with application monitoring from AppDynamics Isolate bottlenecks and diagnose root cause in seconds. Start your free trial of AppDynamics Pro today! http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
