On 27 April 2010 17:25, John Kasunich <[email protected]> wrote > On Mon, 26 Apr 2010 11:22 +0100, "Andy Pugh" <[email protected]>
>> The power modules I have been looking at recently >> seem to work best at about 10kHz PWM frequency, well within the >> capability of EMCs existing software PWM generation. > > 10kHz is not really within the capability of software PWM. You beat me to it, the error in my reasoning occurred to me on the plane this morning. 10kHz update frequency is easy, a useful 10kHz PWM is a rather different thing. It is also rather out of the scope of the AVR microcontrollers, which have a max PWM rate of (Base Clock / 512) I should also point out the other error I made earlier in the thread. Holding the low-side drivers of that module I pointed out low all the time will not have the effect I said, it does need 6 drive signals. It might be possible to drive it with a logic-level inverter. I confess I am rather unsure what a sinusoidal three-phase PWM signal looks like, ie what the relationship is between high-side active and low-side active for each phase. -- atp ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
