3 Phase brushless AC/ ACIM motors

[cts_casemod]

I am wondering if I can use the teensy for motor control applications. I know the STM series does come with a 3 phase 6 output driver with dead time generation, so wondering if the teensy has this feature and if someone has used it?


Regards

 

[PaulStoffregen]

Yes, it's possible. The FTM0 timer has those 3-phase dead time control features.

So far, I'm not aware of anyone actually doing such a project, nor any libraries available to make those hardware features easy to use.

 

[cts_casemod]

Cool Paul. That's what I need. So I assume all the relevant pins are available?

Does the board also have the internal comparator's available for OVC measurement?

I started up with a dspic33 and gave up. I was having too much trouble getting the peripherals (i2c, spi) to work. The actual motor worked fine in open loop.

Any guides on direct port access on the teensy3 I may start to play with it later.

 

[PaulStoffregen]

So I assume all the relevant pins are available?

Yes, of course.

Does the board also have the internal comparator's available for OVC measurement?

Yes. Again, for the comparators and special PWM features, there aren't easy to use libraries. The chip has a LOT of advanced features, which gives you a lot of capability, but also a lot of complex documentation.

http://www.pjrc.com/teensy/K20P64M72SF1RM.pdf

Any guides on direct port access on the teensy3 I may start to play with it later.

For direct port access, I highly recommend using digitalWriteFast() and digitalReadFast(). First, use normal pinMode() to configure the pin. Those "Fast" functions always compile to the minimal code when their inputs are constants.

You can also access the chip's registers directly, if you really want, but that's a lot more work (and results in exactly the same speed as using digitalWriteFast and digitalReadFast).

 

[PaulStoffregen]

For the advanced motor control PWM stuff, refer to chapter 36 "Flextimer Module (FTM)" starting on page 769.

There's a pretty tremendous number of features. The timer actually has 2 modes, a simple "TPM compatible mode", which is the default, and the "FTM mode" where a all the advanced features for motor control features are available (and certain registers have slightly different behavior). The mode is configured by the FTMEN bit in the FTM0_MODE register, documented in section 36.3.10 on pages 788-790. You'll probably want to turn that feature on.

Deadtime control is done with registers starting on page 801.

I have not personally used any of these special PWM features (yet), so this is pretty much all the help I can give you... pointing out the sections in the reference manual where you can find the documentation.