For anything you'd like to see added to Speeduino
User avatar
By PSIG
#47439
JHolland wrote: Mon Jan 04, 2021 8:22 am Things often appear to work correctly if you don't test thoroughly - at 300Hz you would have 100% ripple current on a typical throttle body.
@JHolland - what seems a good method to find a reasonable frequency? Reduce ripple until excessive torque is lost? Or some other method? For max torque, I run motors at 5T of L/R (*2=Hz), but of course that is accepting full ripple and reduced motor life. :? Any suggestions?
By JHolland
#47443
PSIG wrote: Mon Jan 04, 2021 8:37 pm
JHolland wrote: Mon Jan 04, 2021 8:22 am Things often appear to work correctly if you don't test thoroughly - at 300Hz you would have 100% ripple current on a typical throttle body.
@JHolland - what seems a good method to find a reasonable frequency? Reduce ripple until excessive torque is lost? Or some other method? For max torque, I run motors at 5T of L/R (*2=Hz), but of course that is accepting full ripple and reduced motor life. :? Any suggestions?

Running the current control loop at 5 to 10 times the electrical time constant of the motor is about standard, the control loop is usually synchronised by the PWM interrupt so you run at multiples of the loop frequency. If the manufacturer doesn't specify a maximum ripple then its a bit of guesswork. With a low-z motor like on an ETB they are audibly very noisy at low frequencies - you're looking at 2Ap-p at around 500Hz and if your ADC isn't synched to the PWM then the current reading will be all over the place and the system unstable.
The chips I've used for ETBs run up to around 10kHz, that gives an upper limitation, then its down to the clock frequencies available on the chip.
I've got a Denso ETB motor on my dyno at the moment, I'll see if I can get some scope captures later.

I've been away from playing cars for a few weeks, […]

Vr Conditioner Noise when cranking

you could set 'skip revolutions' to 3, then it wo[…]

I uploaded logs and last tune and dyno plots look[…]

Hi, I am trying to assign Signed values to the x-a[…]

Still can't find what you're looking for?