kiwifiat wrote: ↑
Mar 25 2020 8:00pm
If you are looking for 4kW per controller then this design by Lebowski will do the job:
It is also easy to assemble and takes the BobC Lebowski brain directly.
i appreciate you pointing me to it...if i can't afford any other method, i probably already have most of the parts from other failed attempts to build those powerstages (assuming i can actually build them successfully). i'd just have to send off for a pair of pcbs, and find the electronic bits n my bins or in other "dead" electronics (except the gate drivers and the current sensors). i should even have some 150a 100v fets in the right to-case style in my ancient "controller experiemnts" bin that haven't been used yet.
but so far i haven't even been able to get some of the build/wiring/etc stuff for my trike lighting and control switches unit done, between time, energy, not-so-great-aging-eyes, and my hands-randomly-go-numb problem (which only really happens a lot when i actually need to do things like this).
so, simple or not, i'm not sure i would get that unit done right without too many fried things. (i've tried to build controllers / power sections before, and never got them working right; just kept blowing stuff up with no reason i could find). technically, i've got a degree as an electronics technician, but while i understand quite a bit of basic stuff, an engineer i am not.
so wherever i can simply "hack two things together" to make something do what i want, it usually works out...whenever i have to build it from scratch, it doesn't usually work out....
i'm not exactly a normal thinker, either. (in case you can't tell from my wierd posts)
fwiw, i have a couple of the bobc power boards that use those six-fet ixys chips, and was going to try my hand at building them up, as they're pretty simple, but i can't find anywhere to buy the chips anymore.
the one place that will still let me order them (but doesn't actually stock them) requires something over a dozen as a minimum order (i only need two, maybe three if i wanted a spare chip), so it'd cost a few hundred dollars.
but in either case, i'd need to buy six current sensors, and that's another large expense. (apparently they come in the honda ima already)
The Honda IMA will also work but is overkill for your application
i don't mind overkill, as long as it isn't expensive, and isn't gigantic. overkill leaves room for expansion of my needs.
the trike is large (for a bicycle-trike), but that's so it will fit large or lots of cargo (or the dogs) in the back, and small cargo under the seat. there is room for electronics under the cargo deck but it has to be water-sealed at least fairly well because we do get flash floods, and i have at least twice ended up in water inches above the cargo deck top. (the actual water level was lower than that, but waves from passing cars and from me riding into the flooded street slosh it a lot higher). when it does flood i don't usually have a choice of routes at that moment, that would be any better. doesn't last long, but long enough to force me into riding thru it, usually to get home from work. :/ so far cheap chinese controllers have survived.... so it doesn't have to be perfect sealing, just good enough.
and it requires a 12V supply in order to power the isolated gate drives which may or may not present an additional hurdle for you.
a simple dc-dc from the traction battery ought to be able to do the 12v, right? would one dc-dc work for two ima's, or would it require separate ones for isolation? how much current would be required? i'm sure i can find a cheap but reliable 12v dc-dc i can use for this, if i don't already have something (like an ac wallwart that can run from dc; i have a dell laptop charger brick that does several amps that might work, and several other similar bricks).
It may not be too difficult to hook a BobC Lebowski brain into a dead Kelly provided you can identify the gate drivers and of course they were not fried when the Kelly failed. Do you have any photos you could post of the Kelly internals that might help?
not yet; i don't have the kelly's yet. still waiting on maitilupas to reply; could take a few weeks of back and forth to get a purchase worked out, guessing $80-$100usd including shipping for a pair of kbs72181e's that in his words, are "in brick mode one because of a failed auto identification and the other from a fall down. they both have a red permanent light , i cannot connect them to the pc.".
the first one sounds like the typical "self-bricking because you spun the motor while connected to the pc" problem some kellys have, the second sounds like it was from a crash that could've damaged fets (if the phase wires shorted), but if the crash just damaged control wiring the fets are probably still good. i don't know how long it will take to get those kinds of details from him.
the gate drivers are probably discrete transistor stuff, like most of the generic controllers out there, so probably easy enough to identify the input to them coming from the mcu.
but if i can get honda-quality stuff for not much more than that, with essentially the same challenges of hooking them up to the brains, i'd rather do that than mess with the kellys.
i also don't mind being a "beta tester" for how to work out hooking them up and setting them up, if y'all would like, as long as it doesn't prevent me from using the trike as my commuter every day (especially nowadays, as i could get called in to work again for overtime when others don't show up due to the virus thing).
if there isn't already a thread somewhere on how to use the imas with lebowski brains, with great detail about resources, parts suppliers, costs, what pins / wires are what, what signals go where, etc., one should be started; i can help write / edit / etc. if needed. (i just need the information itself). if enough info is present, it could be a good start on getting people into more reliable controllers for their higher power projects, rather than going with the "typical chinese stuff" that doesn't have much (if any) support or information out there.