DRV8302 sensibility

thanks . I thought it was programmed by the  STM32 .

I ask that , because I have intempestive accel/brakes at 80% duty  on flat floor near Vmax .

 I know problem with observer  become noisy at this duty and low current ( 5A/motor in my case ) , on VESC4.xx with 2 shunts ..

 so 2 solutions :

 1) I push ' sensorless ERPM ' over my Vmax  , always in sensored mode . some says it's noisy , but I use big hoverboards hubs , Kv18 and 12000 ERPMmax in 12s ..

2) I use 40V/V gain to augment sensibility on current sense , and quadruple Current Max  and braking . (functionnal current : 25A/ motor max )

3) I keep 10V/V and  modify shunts to 2 or 3mOhms for better sensibility , and double or triple Current Max  and braking .

I will try ..

thanks .

 i tried to use foc sensored over my erpmmax (~11500 full batt.)  , it solve my intempestive accel/brakes problem . but it' a little noisy and I can't reach Vmax . 

pity not to be able to use the hall sensors up to my max rpm. or 900rpm .

 you say problem is related to back emf . i have hubs hoverboard motors with these parameters detected :

141mOhms

299uH

19mWb

KP 0,3

KI 141

observer gain 2,9

if back EMF is not high enough, there is no solution ? 

modify observer gain ?

another value ?

find a VESC6 ? 

thanks .

 i tried to use foc sensored over my erpmmax (~11500 full batt.)  , it solve my intempestive accel/brakes problem . but it' a little noisy and I can't reach Vmax . 

pity not to be able to use the hall sensors up to my max rpm. or 900rpm .

 you say problem is related to back emf . i have hubs hoverboard motors with these parameters detected :

141mOhms

299uH

19mWb

KP 0,3

KI 141

observer gain 2,9

Kv ~20

if back EMF is not high enough, there is no solution ?

modify observer gain ?

another value ?

find a VESC6 ? 

tried BLDC yesterday .. work fine .. but sorry ,too noisy I'm a Foc lover 

I will calculate these values , with my milliohmmeter values .

 but flux linkage isn't proportional to magnets size/force ?

I use these old rolls bike trainer to reproduce my foc brake/accel problem .

Safer than ride 

not being able to reproduce the phenomenon, I went for a ride ... bad idea .. nice fall and very bad shoulder / ear / wrist ..
in short. I have a log !!

the rest of the time my hubs are working fine. acceleration, speed, braking (even if it grumbles a little in hard braking), no engine or esc heating .. I no longer understand.
look at the 95% duty continue as the current reverses and the speed drops. Id and Iq also have a strange behavior.
this happens when the current drops below 10A and duty almost to the maximum...
but not on my chassis dynamometer. .


I'm going to put some ice ...

I also noticed an oscillation of the motors on my unbraked dynamometer, but still presenting a slight resistance. test with the 3 modes of the L / M / H remote control. no worries with the wheels in the air .. I'm looking .. can we adjust the reaction time of the closed loop somewhere ?. I am not familiar with microprocessors and their code, but I am familiar with  oscillators . here we have a loop band problem. it lacks depreciation.

yes . at low current and "high" speed and duty ,vesc want to reduce something .

It reminds me of YOYO's problems on Xiaomi M365 scooters when the motor reaches its maximum physical speed.

"And it is recomended to use a big bypass cap. around 22000uf near the drivers supply, maybe it simply solves the problem"

good idea . but at ~5A battery , should the present capacitors be sufficient?

I have no problem on a steep hill at "high" current (2x30A)

but i will  try .

good news . increasing flux linkage decrease oscillation .

detected at ~16,5 , better at 18~19 .beyond that the engine begins to knock a little. I don't know which parameter influences the linkage flow, but it intervenes in the reaction time of the loop. I must go back and try .. when my shoulder is better ..

18mWb and gain 3 . like detected . but it often detect 16mWb.

resistance measured  ~380mOhms . detected 140mOhms.

but i've seen in MOTOR<>GENERAL>AVANCED . my DUTY CYCLE CURRENT LIMIT is at 100% . it should be at 85% for e-skate applications ..perhaps the solution.

I've found this on help page :

Warning! For E-Skate and some other applications you now need to set DUTY CYCLE CURRENT LIMITS.

Warning! Failing to set the duty cycle current limit value to 85% on all VESC motor controllers in your system will affect your ability to keep the balance when reaching top speed! 

and here is my morning test .. effectively , with 85% , the current never becomes negative, as in the log of my fall. left gragh 85% , right 100%)

and here , test with 16 and 18mWb . less oscillations at 18 . cogg at 20 .

thanks for your advice . everything seems to be working fine now. I am now looking for a pilot who wants to test well, the time to repair my injuries.

I still have the brakes which growl at strong current. I will open another post.