Soft-Start

[sdparkes66]

Hi guys,
I've been searching the forums as am sure I have seen somewhere an Arduino being used for soft-start functionality.. Or maybe am just seeing things in my old age !!!

Am sure this has got to have been done before, so before I attempt to reinvent the wheel, does anyone know of who or where I can find info from about this please..

Currently when slowly turning the throttle on the Trike ( similar to this https://e-caddy.com/wp-content/uploads/2020/05/eagle-apple.jpg ) , it starts quite suddenly,no ramp up, ok, it's not going WOT or anything like that, just would be better with a ramp up rather than the initial on/off

Thanks
Simon

 

[John in CR]

It's quite likely to be a controller issue that a band aid won't fix. Bite the bullet and go with a quality programmable controller that has true torque throttle. I assure you it will be the best present you've bought yourself in a while. Take it from someone who put up with jerky launches or unacceptable delays in current ramp up using cheap controllers for many years.

 

[amberwolf]

There's a lot of ways to fix this. If you poke around for "throttle ramping" or similar terms, you'll see circuits you can build, or devices you can buy and setup, that will do one form or another of it.
https://endless-sphere.com/forums/search.php?keywords=throttle*+ramp*&terms=all&author=&sc=1&sf=firstpost&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
https://endless-sphere.com/forums/search.php?keywords=throttle*+ramp*&terms=all&author=&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
and there's other possible searches too.

Zombiess made a Throttle Tamer at one time, but nowadays you'd have to find one used, I think. The Cycle Analyst V3 will also do it, and has a bunch of other features you don't yet know you want.


But as noted above, the "best" fix is to have a controller that controls the torque of the motor (FOC) and not just the PWM (speed), and also lets you setup the throttle curve the way you want it.

 

[sdparkes66]

But as noted above, the "best" fix is to have a controller that controls the torque of the motor (FOC) and not just the PWM (speed), and also lets you setup the throttle curve the way you want it.

Thanks for the search terms, and taking the time to reply, I was searching but stabbing in the dark as to the better term

where would I look for one of these controllers ? Not sure what they are called, and where to source them..

battery pack ( fully charged ) showing 67v and the motor is 1500w

 

[sdparkes66]

It's quite likely to be a controller issue that a band aid won't fix. Bite the bullet and go with a quality programmable controller that has true torque throttle. I assure you it will be the best present you've bought yourself in a while. Take it from someone who put up with jerky launches or unacceptable delays in current ramp up using cheap controllers for many years.

I was hoping a bit of wizardy with an arduino inline with the sense might have some effect ( guessing ).

But, sounds like I may have to dig deep for a controller. ( would still prefer a "home grown" solution)

 

[sdparkes66]

Just thinking out loud here.. I have a 3d printer, could I use a potentiometer and a standard motorbike throttle and cable, to a printed item which would either turn a normal pot or move a linear inline slide pot !!

Am guessing that 0v is required on the sense/signal wire when the controller is powered up ( anyone know ? )

 

[John in CR]

But, sounds like I may have to dig deep for a controller. ( would still prefer a "home grown" solution)

Make your own FOC controller with perfectly tunable throttle response using the chip Lebowski has shared and supported here on the forum.

 

[amberwolf]

Just thinking out loud here.. I have a 3d printer, could I use a potentiometer and a standard motorbike throttle and cable, to a printed item which would either turn a normal pot or move a linear inline slide pot !!

There's a lot of cable-operated throttle stuff out there. There are some projects here on ES, including 3d-printed stuff with halls and pots, both linear and rotary.

I have a thread on how to use a hall-based COT unit with a brake lever to control proportional regen on a controller, that shows one version of the rotary type of COT. I think I got mine from Aliexpress based on a link and report in MSJFoto1956's build thread.

In my SB Cruiser thread I'm now using an ATV thumb throttle cable-puller to run another of the same type of COT, using the Cycle Analyst v3 already on the trike for the PAS control to convert the voltage range of the COT to that needed by the controllers.

There are dozens of kinds of COT out there that you can buy, most of them at least water-resistant, some of them waterproof.

Am guessing that 0v is required on the sense/signal wire when the controller is powered up ( anyone know ? )

That's up to the controller. You'd have to check its' label, if it says, or ti's manual, if there is one. Otherwise, you'll have to experiment to see what it's actual response range is, and what it will power on ok with, and what will cause it to shutdown at poweron.

Commonly the input range is around 1v-4v, but can be above or below either of those. A few use the 0-0.8v range for proportional regen (like the Grinfineons from http://ebike.ca), instead of using a separate analog brake input.

 

[amberwolf]

But as noted above, the "best" fix is to have a controller that controls the torque of the motor (FOC) and not just the PWM (speed), and also lets you setup the throttle curve the way you want it.

where would I look for one of these controllers ? Not sure what they are called, and where to source them..

FOC (field oriented control) is the actual term used for controllers that modulate torque based on throttle input. (the other types generally modulate speed, or rather PWM duty cycle (effectively controlling speed by controlling average phase voltage)).

Sometimes they call them current-throttle or torque-throttle, but FOC is what's actually being done.

 

[TommyCat]

Being interested in hall sensor throttle operations and modifications, and lightly into electronics. I found an acceptable circuit for "soft start" as seen below.

It's main purpose is to "delay" the voltage ramp-up of the output of throttle's hall sensor output for a smooth and easy start-up.
This is a proof of concept circuit that has been proven to work with parts on hand. But depending on the power source voltage, it may drop the top end speed slightly. So definite room for tweaking and improvement, but it's a starting point.

I would always recommend checking your throttle's output first to verify it's operating correctly...

Or perhaps change to a potentiometer type throttle that has this smoother start-up output profile... (but pricey)

For more information on hall sensor throttles, how to test, profile, and modify. See my thread here...
https://electricbike.com/forum/foru...r-throttle-operation-testing-and-modification


Regards,
T.C.

 

[sdparkes66]

This looks really handy, I'll get it knocked together, thank you so much