[DRIVING] Renault Clio Electrique -97

[Ev8]

Edit - Ev8, 500 does sound a bit low but then its results that matter , could you share your parameters, if I have time I'd like to have a look at how that works on the sim. Also what speed do you rev the motors to (higher speeds may need higher ki)?

Sure, i think my low ki may be helping the 2 controllers not fight each other so hard, as lowering it defiantly smooths out and makes quieter a noisy torque oscillation

I plan to find the time to do enough logging to calculate my actual flux linkage and critical currents, just working 6 days a week inst helping
in reality for the power levels i see i wouldn't be surprised if flux linkage is higher

edit: i only rev to max 5krpm as thats probably nearly 5x base speed for mg2 at 320v

(hope im not spamming up your thread)

[Pete9008]

Have been out test driving and tuning.
First I tuned Ki down and also Kp up to end up at Kp 700 and Ki 1200. Feels much better but the oscillation is still there.
Decided to try the Ki/Kp tuning procedure, viewtopic.php?p=45512#p45512.
The result I ended up with was Kp 700 and Ki 1000-2000. So the procedure seem to work well.
Set Kp 700 and Ki 1000 and made another test drive. Drives ok, the oscillation is still there but much less pronounced. A large log from the entire test drive adn also latest parameters.
log 11.csv
Yaris_MGR_FW5_24_2023-01-13.json

Had a quick look at this, the numbers seem slightly lower than last time.
Over the whole run it comes out at Lq=5.25mH, Ld=1.54mH and flux link - 89mWb
Over a shorter section it comes out at Lq=4.95mH, Ld=1.44mH and flux link - 88mWb
Not really a big enough difference to worry about but would like to understand it. The battery voltage is a little lower but not that much. It's possible the changed parameters could have had an effect? Is there anything else that changed?

Sure, i think my low ki may be helping the 2 controllers not fight each other so hard, as lowering it defiantly smooths out and makes quieter a noisy torque oscillation

Thanks for the files will have a look. I think you're right about the two coupled motors being the reason for the low ki.

(and sorry for the thread spamming!)

[bexander]

Had a quick look at this, the numbers seem slightly lower than last time.
Over the whole run it comes out at Lq=5.25mH, Ld=1.54mH and flux link - 89mWb
Over a shorter section it comes out at Lq=4.95mH, Ld=1.44mH and flux link - 88mWb
Not really a big enough difference to worry about but would like to understand it. The battery voltage is a little lower but not that much. It's possible the changed parameters could have had an effect? Is there anything else that changed?

No, only kp and ki changed. In this log a start from home and return home so elevation gradients are included.

When running the sim and comparing the different settings, they give some different motor performance.

Kp 500, Ki 10000

Kp 700, Ki 1000

[Pete9008]

I think that is the trade-off at the moment, low ki helps with stability but high ki helps with control. My feeling is you have tuned it pretty much as well as is possible at the moment, it's just a case of choosing which compromise you prefer.

Hopefully the MTPV stuff might help and once that's done I'd like to revisit an old idea on the control side to see if the ki compromise can be improved.

[marcexec]

Guys,
while I don't understand half the parameters you're talking about (and hope I will never have to!), I just wanted to say thanks for your efforts on bringing this community forward! Especially as you looking after the "small folks" with the MGR.
While not everyone can contribute, I'm sure there are a lot of us rooting for your "success" and are following with anticipation.
(I'm guessing 20+kW all the way to 100km/h would make you quite happy?)
Also a short video from the dash would be cool!

[bexander]

I wouldn't hold my breath for a video...
Yes, 20kW up to 90km/h would be great.
Will also be very interesting to find out what kind of efficency I can get from the MGR compared to the Leaf setup.

[Pete9008]

I'm slightly worried that operating in fw (or mtpv) for so much of the time might have an adverse effect on efficiency. For best efficiency you need to be in the mtpa region. Still wondering whether using the boost converter might actually increase efficiency rather than decrease it. Be very interested to see your results.

Think 20kW up to 90kph is looking like a real possibility too.

[johu]

I think once you've accelerated to 90 kph it might only take 10 kW to stay there. That possibly drops you out of FW. A little upside of high amplitudes, especially with overmodulation, is the reduced switching losses. But yeah, that's all theory.

[Pete9008]

I think base freq for this motor is around 150Hz so I'm guessing that any medium to high speed will always be in fw regardless of power (can't remember the gearing/conversion factor?).

Probably should add a motor input power calculation to the simulator to get a handle on how much moving away from mtpa affects efficiency but unlikely to get to it any time soon.

[bexander]

90km/h is my top speed, I usually cruise at 70-80km/h and to convert to rpm multiply by 65,8, or 4,4 for fstat.
When crusing at 70km/h it consumes approx 6kW, from the battery.
It is possible to take can-logs while driving to get the BMS-data and speed so that it then can be overlayed to the inverter log, to get a good sens of input power.

I will not be able to test boost converter as I'm running with Yaris inverter and it only handles 300V on the input side but I'll be happy to test the overmodulation when the car is up and running again. At the moment I'm trying to make the inverter install permanent, with sealed cable connections and a more solid mount for it.

[Pete9008]

90km/h is my top speed, I usually cruise at 70-80km/h and to convert to rpm multiply by 65,8, or 4,4 for fstat.
When crusing at 70km/h it consumes approx 6kW, from the battery.
It is possible to take can-logs while driving to get the BMS-data and speed so that it then can be overlayed to the inverter log, to get a good sens of input power.

I will not be able to test boost converter as I'm running with Yaris inverter and it only handles 300V on the input side but I'll be happy to test the overmodulation when the car is up and running again. At the moment I'm trying to make the inverter install permanent, with sealed cable connections and a more solid mount for it.

Does that mean base speed is only around 30kph?

I think your temporary install was better than some permanent car mods/repairs that I've seen in the past!

[bexander]

Does that mean base speed is only around 30kph?

Yes, that is what I concluded, 150Hz <=> 34km/h.

[bexander]

I have modified the inverter so I can feed battery power in it's intended place, i.e. bypassing the input capacitor (rated 300V) and modified the DC/DC to accept 400V by replacing 8 resistors and 3 capacitors (rated 350V, now 400V).
Have also made a more permanent mount for the inverter with the inverter facing the other way compared to the test setup.

The mount feels very solid.
Next is to adapt cable harness and sort out inverter cooling.

[Ev8]

any scope to go up a size in tyre/wheel combo? could help increase the speed you can achieve before fw

[bexander]

It's a good thought but if I enlarge the wheel diameter by 10% (maybe possible) it would only decrease the motor speed with the same amount and hence FW at 38km/h (34km/h as is).

[Pete9008]

Looking good. Are you thinking of trying the booster then?

Was planning to do something similar on the DC/DC but hadn't got round to looking at what was involved. Is there any documentation for the mods, particularly the caps?

[bexander]

No booster with the Yaris inverter. It has only 300V rating on the input capacitor and I think you need to have it while boosting.
In the Prius inverter the input capacitor is rated 400V.
In fact, I have removed the booster inductor completely, to save weight (2kg) as I will not use it anyway. The total inverter weight is down to 10,0kg. The Yaris inverter weight about 1kg less than a Prius Gen 3 inverter.

[bexander]

Forgot the documentation if the mods on the DC/DC.
viewtopic.php?p=6942#p6942

[bexander]

For the Prius inverter you only need to change the 8 resistors as the caps are rated 400V in the DC/DC. In fact I used Prius caps on my Yaris DC/DC.

[Pete9008]

For the Prius inverter you only need to change the 8 resistors as the caps are rated 400V in the DC/DC. In fact I used Prius caps on my Yaris DC/DC.

Thanks, that's good to know.

[bexander]

Damned legacy. So yes, on the Prius inverter that will work because it hasn't got the over current comparator. On all other variants the same timer also generates the references for said comparator and thus needs to be high frequency. So if someone were to set it to the new mode e.g. on a Nissan board it would just overcurrent all the time for no apparent reason.
Hmm, could call the mode "PriusConstant" or something

EDIT: could that be a job for the atmega?

Another thought about this. If you add a counter to the main loop and then toggle PB9 (PWM_USER) based on this counter value?
An example:
For 19,6Hz and duty of 51% that would result in PB9 HIGH at counter = 0, PB9 LOW at counter = 228 and reset counter = 0 at counter = 448. Then no need to mess with timer and risk of messing up the overcurrent.

[johu]

Yes, indeed I do something similar for speed frequency mode already in Ms1Task
Didn't think of it

[bexander]

Ok, so maybe this could be implemented in a future SW release?

Then perhaps "pwmgain" could set counter reset value (448 in the above example) and "pwmofs" sets pin toggle value (duty) (228 in the above example).

[bexander]

How do I adjust overmodulation?
Found this:
viewtopic.php?p=51324#p51324
But I don't understand where I'm supposed to change modmax?

I downloaded the latest 5.25 from johu:s github but no trace of modmax in any of the src or include folder files?

[Pete9008]

I think it's at the top of the foc.cpp file in libopeninv/src