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Motor control by torque command

Posted: Tue Jul 13, 2021 5:53 pm
by BLF0005
Hi all,
I've been doing some searching through the forums and the source code and I am wondering if I am missing anything. Essentially my question is if we can control the motor based on a torque request instead of a throttle percentage as is more typical with some of the other of the shelf solutions. If this is covered somewhere I'd love a link or some direction. My VCU software handles all of the cruise control, torque ramps, rpm ramps, etc, etc via torque commands so I'm trying to determine the best way to adapt that to the Open Inverter control Schema. Help or guidance is much appreciated! thanks in advanced!

Re: Motor control by torque command

Posted: Tue Jul 13, 2021 9:27 pm
by P.S.Mangelsdorf
My understanding is that throttle percentage is a torque request, but I could have that wrong.

https://openinverter.org/wiki/Software_ ... _Operation

Re: Motor control by torque command

Posted: Wed Jul 14, 2021 1:04 am
by Isaac96
Pretty sure it's not quite a 'torque request' in terms of a certain pedal position equals a certain torque -- we hit field weakening and the max torque decreases but the pedal still behaves the same way.

Re: Motor control by torque command

Posted: Wed Jul 14, 2021 12:57 pm
by P.S.Mangelsdorf
Isaac96 wrote: Wed Jul 14, 2021 1:04 am Pretty sure it's not quite a 'torque request' in terms of a certain pedal position equals a certain torque -- we hit field weakening and the max torque decreases but the pedal still behaves the same way.
Appreciate the correction.

Re: Motor control by torque command

Posted: Wed Jul 14, 2021 2:40 pm
by jon volk
I think the closest you’ll get is either modifying fweak and fslip over CAN or modifying the firmware to have use a predetermined lookup table of fweak and fslip values that are modified by a new “torque request” parameter. You would have to generate the tables and they would generally be vehicle and drive unit dependent when getting close to an desat fault. I have not had great luck using current limiting options in the software with the LDU as the modulation itself seems to generate overcurrent faults.

Re: Motor control by torque command

Posted: Fri Jul 16, 2021 11:48 pm
by BLF0005
Thank you all for the feedback. From what I'm gathering, it should be possible to calculate the Max torque that the motor is capable of outputting and map that to a 0-1000 value. Typical inverter torque control ignores real time practical torque limits of the motor and simply requests a torque value regardless of whether or not the motor can actually output that torque.