Pedelec/eBike, PAS and sensors

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Mon, 2018-11-19 11:46

sam.vanratt

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Last seen: 1 year 7 months ago

Joined: 2018-11-18 14:09

Posts: 83

Pedelec/eBike, PAS and sensors

Hello all,

because of no reaction in my old vedder.se thread I try it again here. Three years ago I found this interesting controller project. Because of time limitations (and no reaction) I stopped in 2016. No I'd like to continue and change my PWM motor to FOC.

I've decided to buy a VESC controller (V4.12) in order to change my current Pedelec with a more advanced and reliable BLDC controller.
My current Hardware is:
-8S5P LG 29V/15Ah battery
-GoldenMotor MagicPie3 Front (with standard rectangular pulse controller build in + field sensors) limited to 250W (=9A/29V)
-one 12pol PAS Sensor (std. three pin)
-two "Low-Active" Brakes
-one cruising mode (low active afair) button
-one 1-4V thumb control regulator

So far the combination is quite nice as the controller is in the Hub and "tidy", BUT the controller itself already failed three times (this is my fourth controller in nearly 4 years) with different K.O. criteria. When I replaced the last one this January I decided not to wait until this one fails again and do invest into something I'd handle. I've discovered the VESC about two years ago and am astonished what this project already accomplished!!!
OK so I bought a VESC V4.12 (with FW:3.40)

Two things need to be fulfilled:
a) I need to get my two brakes, the PAS, the HALL sensors+Motor
b) the software needs to be trimmed to my hardware (Recuperation, Amperage limit, max. RPM, Speedregulator, PAS settings)

+nice to have
c) try sinus commutation instead of square (makes the hub possibly more silent)

Have anyone used the VESC for such a case? Currently I've not even checked the VESC controller or software itself as I'm still trying to get the max. four JST cables at a reasonable price.

I found out so far that

-(Hall) Throttle will go VCC-GND-ADC1 (while VCC will be 3,3V as the input does not allow anything above 3,3V)

-PAS could be integrated into the throttle (impuls to voltage converter+opamp multiplier with the throttle input); afaik Benjamin has PAS on his todo list, but as my old MP3 has a bad PAS support I already build an analogue part infront of it to have a smooth working PAS

-Brakes: connect the RX and GND

a few questions:

A) is FOC adviseable?

B) does the brakes need a pullup resistor?

C) what are the software/VESC settings to make the system work? The software allows so many features so I'm out in the wood to touch the right one

D) cruising speed switch: is already implemented according to a few older forum entries... but how (which pins) and where (VESC Tool); it seems a simple Sample&Hold function is the right way

Cheers
Sam

P.S.: How do you isolate it from external weather (dirt, water, moisture, snow, rain) and get the cables still in? Is there a usual boxing case?

Tue, 2019-02-26 22:08

e-nduro

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Joined: 2018-11-25 20:05

Posts: 10

any news on PAS / PEDELEC usage?

I am thinking of using an external microcontroller and CAN, but it seems a bit overkill

Thu, 2019-03-07 20:22

sam.vanratt

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Last seen: 1 year 7 months ago

Joined: 2018-11-18 14:09

Posts: 83

Hi e-nduro

well I did reuse my external PAS+Throttle Multiplier circuit which I "developed" to circumvent the bad PAS function in my MP3. As it only consists of three Opamps and R+Cs it was much easier then using some arduino implementation (what an overkill for just that function). PAS seems the last problem to solve; bikers are not the main group for VESC. There are already some firmwares for VESC+PAS available, but I'm surely not someome patching source code together... well I'm not a programmer at all. The right way would be to use some input (e.g. RX to view at the "Baud" rate and decide to allow the throttle; only PAS for throttle is very unhandy when you want to do precise maneufers like railroad crossings. But all PAS Countries I know of do allow PAS+Throttle in combination, so that was my solution.

Cheers

Sam

Pedelec usage in combination with a GoldenMotor MagicPie3 BLDC

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Pedelec/eBike, PAS and sensors