generate an Interrupt, when the motor don't turn

easchlut · ‎2003-07-17

Posted on July 17, 2003 at 10:38

easchlut · ‎2011-05-17

Posted on May 17, 2011 at 10:16

Hello

I have a problem I need the ST72141 as a generator. I want to regulate the speed if the motor is externally propelled. For this I need the zerocrossing times which passed in the Interrupt. But I don't have Interrupts in this mode. In the normal mode when the motor is driven by the processor althing is okay.

Have anyone an idea?

Thanks

Kicker

maxime2399 · ‎2011-05-17

Posted on May 17, 2011 at 10:16

Your problem seems difficult... I have never done it myself, this is just a short analysis of the question.

The way the internal state machine is done, it is impossible to have the Z event (BEMF zero crossing) unless you had before the commutation C and the demagnetization D.

- The commutation: you can imagine having a commutation and a very low voltage/current applied

- The demagnetisation: this should not be a problem, a software demagnetisation is a just a dead time for the BEMF.

The second problem I see is linked to your high side swithes. You have to be careful if you use a bootstrap power supply for the drivers.

The drivers will stop working if you stop commuting the low side switches.

The other approach is just by pooling the comparator output.