Search found 34 matches

by bww129
Aug 31 2020 8:39pm
Forum: Motor Technology
Topic: I'm looking for developers/engineers interested in high current (+1kA) controller development
Replies: 11
Views: 715

Re: I'm looking for developers/engineers interested in high current (+1kA) controller development

Hadn't seen the errata for the G4 series but there is quite a laundry list of items in there! Good thing the ST rep didn't persuade us to go that route! It may be worth waiting to use it after the next couple silicon revisions... The H7 would be a good option too. All the higher end micros start out...
by bww129
Aug 30 2020 9:42pm
Forum: Motor Technology
Topic: I'm looking for developers/engineers interested in high current (+1kA) controller development
Replies: 11
Views: 715

Re: I'm looking for developers/engineers interested in high current (+1kA) controller development

I haven't looked yet at the very deep details of VESC firmware, but I guess some part of the code could be reused for a TI MCU running instaspin. There is also this ChibiOS thing running is the VESC that might not be compatible with TI MCU or instaspin code. I don't know... Developping a complete n...
by bww129
Aug 30 2020 9:27pm
Forum: Motor Technology
Topic: I'm looking for developers/engineers interested in high current (+1kA) controller development
Replies: 11
Views: 715

Re: I'm looking for developers/engineers interested in high current (+1kA) controller development

I suspect that I'm going to surpass the limits of the STM32F405 uC as it's already maxed out when running 60kHz PWM, which should be enough, but I might be dealing with some custom very low inductance motors. ST makes it relatively easy to migrate code between families, or so I've been told by my s...
by bww129
Aug 30 2020 8:26pm
Forum: Motor Technology
Topic: VESC based +200A powerstage with 200V MOSFETs (videos of it in action)
Replies: 56
Views: 3894

Re: VESC based +200A powerstage with 200V MOSFETs (videos of it in action)

I've been thinking about this on and off and after a little digging, found a thermal conductivity figure for Kapton of .12W/m*K. Apparently not all types of Kapton are created equal when it comes to thermal conductivity. https://www.dupont.com/products/kapton-mt-plus.html Dupont's Kapton MT+ specif...
by bww129
Jul 08 2020 11:03pm
Forum: Motor Technology
Topic: VESC based +200A powerstage with 200V MOSFETs (videos of it in action)
Replies: 56
Views: 3894

Re: I designed a +200A powerstage with 200V MOSFETs (video of it working)

BTW, you should make an electric drive for the < 18yr old Yonies to put on their buggies. It always cracked me up when I heard a buggie with a sound system in it bumping some NWA (90s) as the horse went clip clop clip clop. (I grew up in the Lancaster/Berks area). When murdered out cars became a th...
by bww129
Jul 07 2020 12:50pm
Forum: Motor Technology
Topic: VESC based +200A powerstage with 200V MOSFETs (videos of it in action)
Replies: 56
Views: 3894

Re: I designed a +200A powerstage with 200V MOSFETs (video of it working)

benjamin posted a reply to shaman's questions/observations about the inductance measurement error on the VESC forum a few months ago - https://www.vesc-project.com/comment/5097
by bww129
Jun 12 2020 11:36am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 1220
Views: 110345

Re: APL's DIY axial-flux motor

First off, awesome build!

Second, why not go all out and use Litz wire (if your budget allows)? Lots of strands of 36-42AWG wire would pack a lot of copper in there.
by bww129
Jun 09 2020 10:29pm
Forum: Motor Technology
Topic: VESC based +200A powerstage with 200V MOSFETs (videos of it in action)
Replies: 56
Views: 3894

Re: I designed a +200A powerstage with 200V MOSFETs

DC link caps are 500V 90uF 26A ripple each Any reason you chose two large caps over multiple smaller caps? Nice choice moving all the way up to the DC link PP film caps. I'm attempting to use a PCB as the DC bus. Looks like you've more than attempted it! Throw enough layers of heavy copper at it an...
by bww129
Jun 06 2020 1:36pm
Forum: Motor Technology
Topic: True FOC: definition and examples
Replies: 57
Views: 3562

Re: True FOC: definition and examples

Vector control for dummies is a very good read with some excellent animations: https://www.switchcraft.org/learning/20 ... or-dummies
by bww129
May 19 2020 9:39am
Forum: E-Vehicles General Discussion
Topic: The BEST connectors, period
Replies: 51
Views: 8722

Re: The BEST connectors, period

Molex has a Coeur CST high current series - https://www.molex.com/molex/products/family/coeur_cst_highcurrent_interconnect_system Aptiv (was Delphi) has a Ducon high current series - https://www.ttiinc.com/content/dam/ttiinc/manufacturers/delphi-connection-systems/Featured-Products/Commercial-Vehicl...
by bww129
May 15 2020 5:30pm
Forum: Battery Technology
Topic: First DIY pack 24s7p
Replies: 7
Views: 292

Re: First DIY pack 24s7p

That's a massive improvement. Well done.
by bww129
May 15 2020 4:38pm
Forum: Battery Technology
Topic: Best Li-ion cell model for ebike pack?
Replies: 16
Views: 593

Re: Best Li-ion cell model for ebike pack?

I had previously only seen the Samsung 30Q chemistry described as INR/NMC, which is typically Lithium Nickel Manganese Cobalt Oxide LiNiMnCoO2, according to various sources across the internet. I had not seen anyone disagreeing or saying otherwise, so you take what little info you can get, right? Af...
by bww129
May 15 2020 3:36pm
Forum: Battery Technology
Topic: Best Li-ion cell model for ebike pack?
Replies: 16
Views: 593

Re: Best Li-ion cell model for ebike pack?

Some say, that the 30Q is based on a very unusual chemistry. Maybe the quality of the 30Q cells differs from different sources. The INR in INR18650-30Q means they're a Lithium Manganese Nickel chemistry. Is there any evidence that Samsung added something proprietary to make the chemistry "very unus...
by bww129
May 12 2020 10:13pm
Forum: Battery Technology
Topic: Best Li-ion cell model for ebike pack?
Replies: 16
Views: 593

Re: Best Li-ion cell model for ebike pack?

A guess would be that for 7kW you're probably looking at a 20S 74V 100A pack. For the 30Q cells you'd want a 20S10P pack (conservative 10A per cell) or 20S7P minimum (maximum 14.3A per cell). 20S10P gets you 30Ah at 200*48g=9600g. 20S7P gets you 21Ah at 140*48g=6720g. That's 3.125Ah/kg for those 186...
by bww129
May 12 2020 7:27am
Forum: Battery Technology
Topic: First DIY pack 24s7p
Replies: 7
Views: 292

Re: First DIY pack 24s7p

Ideally each cell in the row of 7 would have a connection to the next row of 7 cells for the lowest resistance. The hexagonal groups aren't optimal in this regard. You'll obviously have to get a little creative, but I would try groups in a row of 4 and a row of 3 like the ones you've numbered 8 and ...
by bww129
May 10 2020 8:39am
Forum: E-Bike Technical
Topic: Bafang brake cut-off 3 wires to 2 controller wires
Replies: 11
Views: 1334

Re: Bafang brake cut-off 3 wires to 2 controller wires

I just picked up a pair of these sensors off of eBay to interface to a CA V3. After cutting the plugs off and probing for the open/short circuit pin pair I noticed that the wire colors were different on the sensors I received. The reed switch is between pins 4 and 8 as labeled in the picture above, ...
by bww129
May 09 2020 10:36pm
Forum: E-Vehicles General Discussion
Topic: How to weatherproof bullet connectors?
Replies: 12
Views: 692

Re: How to weatherproof bullet connectors?

Molex Permaseal butt splices are a good option. You'll have to cut off the bullet connectors though.
by bww129
May 08 2020 10:52am
Forum: Battery Technology
Topic: Battery data analysis by CANoe software
Replies: 1
Views: 164

Re: Battery data analysis by CANoe software

I've worked with CANalyzer quite a few years ago which I believe is similar to CANoe. I'm sure the SW has changed a lot over the years. Isn't there an option to export trace data in a comma/tab delimited file format? That would probably be easier to process/parse with Python or even something simple...
by bww129
May 07 2020 9:04pm
Forum: Battery Technology
Topic: Does this make sense with Hobbyking packs?
Replies: 8
Views: 514

Re: Does this make sense with Hobbyking packs?

If you want top speed on a budget and don't mind balance charging multiple packs then try some HobbyKing packs. I just bought three Turnigy 4.5Ah 6S 30C packs from HobbyKing when they were on sale for $40 each because I wanted to try 18S at 67-72V instead of 14S at 52-56V. Add a few sets of XT90 con...
by bww129
May 05 2020 2:08am
Forum: Motor Technology
Topic: Serious FOCer (84V VESC 6 based controller)
Replies: 286
Views: 40642

Re: Serious FOCer (84V VESC 6 based controller)

It took a few days to read through all your FOCing FOCer threads :D (great name choice) but it was well worth it to see such a great effort documented. Kudos for the multiple iterations and keeping with it this long! You must not have any kids and enjoy working long hours :wink: On a technical note,...
by bww129
Apr 29 2020 11:16am
Forum: E-Bike Technical
Topic: 72v li-ion battery problems
Replies: 9
Views: 418

Re: 72v li-ion battery problems

I find it interesting that the odd numbered pgroups voltages are different than the even numbered pgroups or column 1 is higher than column 2. maybe its the way the bms operates and not the battery. Some of the ICs used in BMSs have dual ADCs and can sample two voltages at the same time. It is poss...
by bww129
Apr 29 2020 10:33am
Forum: E-Bike Technical
Topic: 72v li-ion battery problems
Replies: 9
Views: 418

Re: 72v li-ion battery problems

Do you know the voltage accuracy of the BMS? Some of the higher quality ICs used in BMSs are accurate down to 1-2mV, but that depends on implementation as well. You probably shouldn't worry too much about small difference in cell voltage difference under load, especially if the pack is new and uses ...
by bww129
Apr 29 2020 9:51am
Forum: E-Bike Technical
Topic: 72v li-ion battery problems
Replies: 9
Views: 418

Re: 72v li-ion battery problems

What battery is it? Are the BMS cell voltage taps wired in exactly the same position for each cell? It doesn't take much extra added resistance to mess up a measurement at high currents: 20A through 1mOhm is 20mV.
by bww129
Apr 29 2020 9:39am
Forum: Motor Technology
Topic: True FOC: definition and examples
Replies: 57
Views: 3562

Re: True FOC: definition and examples

Just to throw another definition out there, on page 38 of this ST presentation it states: "The objective of the [FOC] algorithm is to control the vector components of the stator magnetic field (i.e. the phase currents) in order to obtain the target intensity and phase relation with the rotor magneti...
by bww129
Apr 29 2020 5:23am
Forum: E-Bike General Discussion
Topic: Repairing a shunt on a mainboard
Replies: 44
Views: 1025

Re: Repairing a shunt on a mainboard

Obviously you don't know what value the shunts were, but have you searched to see if someone else has reported their value? What controller is it? Can you post a picture of what they look like? If the controller is trying to read the phase current but you effectively changed the resistance to infini...