I am wondering if the SAM3X8E hardware can manage 6 PWM outputs running at 10 to 20KHz which would be needed to drive a 3 phase bridge to create an inverter for induction or synchronous motors? It would need to be able to generate sinewaves via pwm and the duty cycles could either be calculated in realtime using a sin(x) function or stored in a table.
What voltage are You thinking about and which currents?
I am wondering if the SAM3X8E hardware can manage 6 PWM outputs running at 10 to 20KHz
It can be done with a DUE.
Search in the DUE sub forum for example sketches with direct register programming to output several PWM pulses with variable duty cycles and dead times.
It could be any range of voltages and currents as the due will be attached to IGBT or mosfet gate drivers. I was thinking to start with, I would maybe make a 72v 30 amp controller with regen. If I find out that the due is suitable for this kind of stuff, I will move on to over 300v at 200 amps plus for an electric tractor project.
In response to ard_newbie
Can it produce PWM that's perfectly in phase? For example, for regen, the bottom three mosfets have to all be pulsed at the same time as shown in the attached diagrams.
You can obtain any phase shift you want for phase v and phase w from phase u.
1/ Set 3 synchronous PWM channels (u, v, w)
2/ store a full period of phase u into a buffer
3/ Program phase v to be 120 ° phase shifted from phase u, and phase w 240 ° from phase u
4/ Start the outputs
I know that any phase shift can be achieved but I am meaning the phase of the pwm pulses themselves. I am concerned that some pwm outputs may switch on slightly before others due to having to use different timers for each output due to limitations in the hardware. Yes, the sinewaves need to be 120 degrees out of phase but the PWM pulses themselves must be perfectly in phase on all outputs.
The synchronous PWM feature of the Sam3x between several PWM channels provides an exact accuracy.
There is a "Master" PWM channel (PWM channel 0) which provides frequency for all the other PWM synchronized channels.
Perfect, thanks. I will get a due and look in to developing and releasing a controller with regen. May take a few years lol.
I would maybe make a 72v 30 amp controller with regen. If I find out that the due is suitable for this kind of stuff, I will move on to over 300v at 200 amps plus for an electric tractor project.
72 x 30 = 2.1kW
300 x 200 = 60kW
You will be looking at some very expensive IGBT modules.
Can you please tell us your electronics, programming, arduino, hardware experience?
My programming experience is limited but my ability to work with hardware is much better. I have already developed a working battery management system using nothing but analog electronics. As for the more powerful inverter, I may just use the power stage from an inverter salvaged from an electric car as it comes with the capacitors, gate drivers and of course, the IGBT modules.