Field weakening

Nissan Leaf/e-NV200 drive stack topics
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Riwi
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Field weakening

Post by Riwi »

Hi!

I’ve started to play around with the new features regarding field weakening. I got a 24s, 88v, battery connected to the inverter. Precharge and closing of main contactor works like a charm.

I upgraded sw to 5.24.R-foc and applied the config found in the database for em57.

I can control start, fwd and rev. But if I give to much throttle the rpm takes of like a rocket.

My guess is syncofs, given the information in johu’s video on the subject.

Two questions:

1. What do s the proper way to stop/shutdown a motor that spins out of control? Stop inverter from gui, power off?

2. Syncofs is set to 1000 now. What values do I log/plot in order to get an indication of the value for syncofs?


Thanks!

Rikard
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johu
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Re: Field weakening

Post by johu »

This is still in effect: https://openinverter.org/wiki/Using_FOC_Software

For an unloaded motor I'd recommend setting fwcurmax=0

The torque it spins up with is rather low. Anyway I'll work on the rev limiter later.
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Romale
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Re: Field weakening

Post by Romale »

johu wrote: Mon Jan 30, 2023 10:42 am This is still in effect: https://openinverter.org/wiki/Using_FOC_Software

For an unloaded motor I'd recommend setting fwcurmax=0

The torque it spins up with is rather low. Anyway I'll work on the rev limiter later.

alas! even a very loaded motor can go into uncontrolled acceleration up to 14,000 rpm.

the attenuation current (fwcurmax) was -500, the battery voltage was 380 volts, the speed limit was set to 800 hertz, the motor and the Nissan leaf inverter gen2. syncofs 1000. the buggy suffered so quickly with a sharp pressure on the gas pedal that the driver did not have time to turn off the ignition, the hydraulic brakes + a signal + 12 volts for the brake input to the controller could not stop the buggy and my friend knocked down some trees and then a fence. No one is accusing anyone, we all understand that this is an open development on our own responsibility. But it wouldn't be bad if the +12 input to the brake was guaranteed to turn off the torque or that the speed limit still worked
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johu
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Re: Field weakening

Post by johu »

Not pleasant to hear. Was it the first test drive? Was syncadv set up correctly? (10)

In overspeed you can't just "turn off the torque". Either it can be controlled as intended or you have to kill PWM which will result in a massive regen surge.

Next test without trees in the way then and I'll revisit the speed limiting topic.
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Re: Field weakening

Post by Romale »

johu wrote: Thu Apr 20, 2023 6:25 pm Not pleasant to hear. Was it the first test drive? Was syncadv set up correctly? (10)
yes, the syncadv is set to 10. all settings are saved by those that go everywhere by default. in addition, some of the settings are not generally known for what they are responsible for and without understanding how to configure them and whether I need to not change them. The next test will not be soon. we need to fix everything. Maybe I'll get my old buggy back together faster (disassembled for suspension reconstruction)
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Re: Field weakening

Post by johu »

Wow, yeah well glad nobody was hurt then.
Please try to collect as much data as possible of the incident so we can understand it
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