On 25 April 2010 18:28, RogerN <re...@wildblue.net> wrote: > In your opinion, do you think the Arduino would work to use as an amplifier > by using 1 resolver and adding 3 phases of PWM to drive 3 half H-Bridges?
Yes. The answer is now a definite yes. In fact since the question was asked about 2 months ago (it seems longer) I have found several ways to do it, but the one that I got going today was a purely Arduino + Power semi system. The Arduino produces a sinusoidal excitation for the Resolver, amplified and low-pass filtered by a power op-amp, the return voltages are measured and decoded into an angle, which is then converted into a Psuedo-Hall sensor pattern and used as the lookup into a commutation table to choose 2 of 6 pins to drive. The 6 pins are taken to a buffer IC which has the "enable" pin connected to a 20kHz PWM from one of the Arduino PWM generators with a duty cycle based on a third analogue input voltage (I have a speed-pot connected at the moment). The drive PWM is taken to a separate power board consisting of a bridge rectifier and a big capacitor as the DC 300V source, and an IRAMS10UP60A (600V, 10A, £15) driver IC (and a set of opto-isolators). http://docs-europe.origin.electrocomponents.com/webdocs/0dca/0900766b80dca34e.pdf That is basically all there is to it, and it runs the 500W servos like a champ. Very fast and very powerfully. I don't expect to keep it in this configuration, I anticipate keeping the resolver-to-quadrature parts of the Arduino code, taking the quadrature signals into EMC2 and then using one of the Hostmot2 3pwmgens and one of the BLDC motor drivers that have been written for EMC2 HAL in the intervening months. I will keep the power driver and anticipate experimenting with a minimalist setup of just the power driver, quadrature conversion and Parallel port in order to see what the minimum-cost option is and just how poorly it works. On the actual machine I am not sure how I will do it, there is almost an embarassment of options now. -- atp ------------------------------------------------------------------------------ ThinkGeek and WIRED's GeekDad team up for the Ultimate GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the lucky parental unit. See the prize list and enter to win: http://p.sf.net/sfu/thinkgeek-promo _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
