Power PCB for Lebowski Controller to be combined with Bobc's processor board

[izeman]

nice motor you got there

[Lebowski]

nice motor you got there

Wouldnt know what to do without it thanks for letting me borrow it

[Altair]

For those thinking about stacking multiple power boards, there is a nice application note here on how to combine the outputs of current sensors.
https://www.google.ru/url?sa=t&rct=j&q= ... cYGVCX_8mM

[Altair]

On subsequent iterations of this great board, it might be nice to plan ahead to make it fit a waterproof enclosure. For example, I like this one:
https://www.hammfg.com/part/1457K1202BK

The stand-offs won't be necessary anymore as the board will slide in slots in the case. (Leave clearance between tracks and edge of slots.)

The brain board will have to be repositioned on the component side of the power board. If necessary, an aluminum shield could be installed just below the brain board.
All power leads can exit on one end of the case, and the control signals come in through a waterproof DB-15 on the other end of the case.

[whereswally606]

one issue with flipping the brain board from beneath is that the led will face the powerboard and so be less visible. Not a big issue but something to be aware of. It does make the overall height less which is good but as Altair said may require shielding. No show stoppers which is great.

[Altair]

...or reverse the connector so the brain board is facing up. Requires rewiring of PCB traces.

[whereswally606]

true but I don't think its worth it. Lebowski's call though

[Lebowski]

For those thinking about stacking multiple power boards, there is a nice application note here on how to combine the outputs of current sensors.
https://www.google.ru/url?sa=t&rct=j&q= ... cYGVCX_8mM

The file shows a very complex method which is not applicable here... The file is for two current sensors with opposite polarity. They need an opamp curcuit to deal with the opposite polarity... When stacking two power boards you will have equal polarity so you don't need the opamp circuit.

Much easier is a passive resistive adder:

03040.png (4.52 KiB) Viewed 1070 times

[Altair]

Yes it's a bit complicated, but it allows to sum currents of any polarity together, it removes the offset and allows to adjust gain. But I agree, the passive averager will do the job.

[minimum]

Any suggestions for replacing, it's out of Digikey stock:
supply cap 270uF 3 565-4018-ND ?
Is ripple current important or are the basic parameters enough (capacitance, voltage and dimensions)?

BTW, ACS770-150B is pretty hard to find from other shops (Digikey stocks 2+k)

[Lebowski]

Any suggestions for replacing, it's out of Digikey stock:
supply cap 270uF 3 565-4018-ND ?
Is ripple current important or are the basic parameters enough (capacitance, voltage and dimensions)?

BTW, ACS770-150B is pretty hard to find from other shops (Digikey stocks 2+k)

I would just make a list at digikey, adding restrictions and then sorting by ripple current:
https://www.digikey.ch/products/en/capa ... ageSize=25

this leads to the top contender: https://www.digikey.ch/product-detail/e ... ND/5818025

But in the end what counts (according to me at least), as long as they don't get warm you're OK. Having caps with high ripple current allowance and low ESR increases the chance of them staying cool.

About the current sensors, maybe other shops still stock the old version, the ACS 758 ? And the 150, this depends on the current you want, there are 50B, 100B, 150B and 200B versions. The 'B' denotes bi-directional which is MANDATORY for the controller.

[whereswally606]

Hey Minimim, I bumped into the same thing yesterday. comparing the spec this is the alternate I came up with based on fit and similar electrical characteristics and its also in stock.

565-4142-ND

Manufacturer Part Number
EKZN101ELL271MK30S

Description
CAP ALUM 270UF 20% 100V RADIAL

I think the resistance was lower so would fill quicker?

[minimum]

Thanks for helping to clear that.

Now another one - seems like the price difference between ordering one and ten PCB's can be up to five times.
So reasonable would be to cooperate (maybe even with parts). Anyone interested in taking this on?

[whereswally606]

I will take this on, along with the group buy for components from digikey.

cap processor board supply 100uF 1 P5595-ND
cap battery measurement 100nF 1 478-4855-ND
gate driver IRS2186 3 IRS2186PBF-ND
high voltage schottky diode MBR1100 9 MBR1100GOS-ND
power FET IXTH180 6 IXTH180N10T-ND
isolation pad 6 BER169-ND
supply cap 470nF 3 495-4996-1-ND
supply cap 270uF 3 565-4018-ND
current sensor ACS770-150B 3 620-1540-5-ND
temp sensor DS18S20 1 DS18S20+-ND
power resistor 22k 3 22KWCT-ND

vat in UK is 20% which I have added in.

This BOM for me alone comes to circa £70.08
4 sets
£247.07/4 = £61.77
5 sets
£307.46/5 = £61.49

Next appreciable difference comes when the sensors etc (items of 3) hit 25 so 8 kits (I know 3*8=24)
£473.7 / 8 = £59.21
because at that point you get a few free items where 10 of something is cheaper than 8 of something as well as it being cheaper overall.
but beyond that its hard to make any reductions in price.

Also there is no huge drop in mosfet cost at 25off (price breaks are 1,10,100)
So if people have a preference of mosfet let me know. (your costs will be altered accordingly.)
Infact there are not that many of these in stock so for reasons of not having something on back order people ordering different mosfets might be beneficial.

Anyway, it not a huge saving, maybe just one in effort but I'm happy to do it either way.

I haven't looked into pcbway costs but I have an account with them and can sort this too.

[Lebowski]

Just a warning regarding the ITXH180, they are limited to 75A by the max allowed leg current... They can probably do 180A pulses or something but only 75A RMS, so at low motor speed (maybe motor stuck ?) they are limited to 75A phase current.

Thanks emmgee for pointing this out to me

[whereswally606]

so Is that true of any TO-247 fet?

So the other Fet people have mentioned for this is the 4468

and looking at a price break of 10

4468 = £6
IXTH180 = £3.8

so £36 or £22.824 per six fet stage

but the spec on the 4468 are much more impressive.

alternatively MTI85 chip is £20.40 (but you need a different powerboard)

[whereswally606]

I have put an order in for 10 power pcb boards connector such that the brain is below the board as per the videos. (not above with the other discretes).

Will pass audit today and will hopefully be with us within a month. Hopefully if I can get organised I can get all the parts for a full kit put together by the time the pcbs get to me, then I will send them out together as one parcel.

will send a break down of cost with each one to help people understand what they bought.

[emmgee]

FET considerations (from a non-specialist):
* IXTH180N10T-ND
advantage: much lower gate charge and rise/fall time than IRFP4468, cheaper
disadvantage: the silicon capabilities are good (180A @25°C), but probably due to small inner bondage wires from the legs to the silicon the I_RMS is indicated as only "75 A I_LCRMS Lead Current RMS", RDS_on = 6.4 mOhm max. on-resistance
* IRFP4468
advantage: very low RDS on of 2.6 mOhm max. on-resistance, 195 A I_Dpackage @25°C, proven on ES to deliver 160A I think.
disadvantage: more expensive

As Lebowski was able to tune both FETs to a very nice and short (~300ns) switching behavior, I would prefer the 4468 allowing twice as much I_RMS

* MTI 85W100GC: bought a bunch without using them yet... with 90A_cont @90°C, only 3.2 mOhm R_DS(on) and very low gate charge they seem to be very cool. The very compact form invites to use them stacked up following Lebowskis original vision of paralleled Power-PCBs. If I could take the hurdles of KiCad I would adapt the Power PCB for the MTI 85...

[izeman]

* IRFP4468
advantage: very low RDS on of 2.6 mOhm max. on-resistance, 195 A I_Dpackage @25°C, proven on ES to deliver 160A I think.

confirmed. absolutely no problem with the 150A i used it. did even get more than hand warm.

[whereswally606]

I have ordered 10 power pcbs to be combined with kits to build the complete power board which are to be sent out with a working tested brain board.

I used china post since ive never had customs charges with them but always with dhl and I don't really know about the other couriers.

Anyway. My paypal is now sitting at 37pence so I will have to wait till the 26th before I can afford the digikey order.

I will direct a few pms to people to ensure I have their complete orders, but if any one wants in on this group buy for the power pcb that Lebowski shows in the vids then pm me

* MTI 85W100GC: bought a bunch without using them yet... with 90A_cont @90°C, only 3.2 mOhm R_DS(on) and very low gate charge they seem to be very cool. The very compact form invites to use them stacked up following Lebowskis original vision of paralleled Power-PCBs. If I could take the hurdles of KiCad I would adapt the Power PCB for the MTI 85...

Bobc already had a design for this (now on my pc) using surface mount so when I get around to it I will order a few of these too. but Lebowski's DIY powerboard takes priority right now as it can be fixed easier and has both myself, Lebowski and Emmgee invested in testing it.

[whereswally606]

https://endless-sphere.com/forums/viewt ... 1&t=93481

see here for group buy thread

[whereswally606]

PCBs on their way to me from pcbway via epacket. just received the email now.

[whereswally606]

LLC ACS770ECB-200B-PFF-T (620-1538-5-ND)
instead of
LLC ACS770KCB-150B-PFF-T (620-1540-5-ND)

Bas should we upgrade to this sensor since we look to all be opting for the 4468 fets and this gives us a bit of head room. Please check my comparison i think this is the direct equivalent upgrade, i dont want to get this wrong. I dont know what the K/E difference in the name is about??? Cost is the same so it seems like a no brainer.

Thanks to everyone for paying up on the group buy thread. Just going to wait on Bas to deny or confirm this upgrade before hitting buy.

[Lebowski]

LLC ACS770ECB-200B-PFF-T (620-1538-5-ND)
instead of
LLC ACS770KCB-150B-PFF-T (620-1540-5-ND)

Bas should we upgrade to this sensor since we look to all be opting for the 4468 fets and this gives us a bit of head room. Please check my comparison i think this is the direct equivalent upgrade, i dont want to get this wrong. I dont know what the K/E difference in the name is about??? Cost is the same so it seems like a no brainer.

Thanks to everyone for paying up on the group buy thread. Just going to wait on Bas to deny or confirm this upgrade before hitting buy.

Oh i just replied to the pm about this. Should not pose a problem, usefulness depends on whether the 4468 can sustain this current level...

[emmgee]

My 50 cents: Testing in a bicycle at 200A will be interesting.... We need a motorbike!
But: With perfectly cooled and driven 4468 the 200A sensors would be the perfect combination, as they have the same theoretical limits. The only little disadvantage is a little bit less precision because the 200A sensors deliver a signal of 10 mV/a compared to 13.3 mV/A (150A version).