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by zombiess
Mar 12 2019 10:32am
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 169
Views: 5924

Re: Cheap FOCer (VESC 4.12 based design)

My vesc used discrete drivers and amplifier.It's cheap and stable. That's really neat and but has jack all to do with the original question, why is the drv8302 "not good"? Personally I use a TD350E in several designs up to around 25kW, it's old, low cost and very robust (Miller clamp, negative gate...
by zombiess
Mar 07 2019 7:10pm
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 169
Views: 5924

Re: Cheap FOCer (VESC 4.12 based design)

I noticed that current drawn affected that magnitude of the spikes more than anything else. This makes sense being that the spike is a reaction to parasitic inductance which in turns increases in severity when there is more current involved. That is expected, but take a look at what happens when yo...
by zombiess
Mar 07 2019 9:39am
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 169
Views: 5924

Re: Cheap FOCer (VESC 4.12 based design)

TEK0000.JPG Vsupply = 50.4V, I Motor = 46A continuous So I did a test at 50.4V with the motor under load. I picked up spikes of 61.6V under these conditions. Note that I could not use low-induction/low-noise measurement techniques as I did before for this test. I estimate at least 3V are attributed...
by zombiess
Feb 21 2019 5:43pm
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 169
Views: 5924

Re: Cheap VESC (VESC 4.12 redesign)

I'm using 10ohm resistors right now for the gates but maybe i'll try higher. I figured I would try and keep the rise/fall time combined under 1% of the switching period. This was some guidance given to me earlier in this thread. Not sure why 1% was suggested for this application, but typically you ...
by zombiess
Feb 21 2019 12:27pm
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 169
Views: 5924

Re: Cheap VESC (VESC 4.12 redesign)

You could reduce your ringing and possibly the need for snubbers by slowing down your switch off time. Looks like you are switching <100ns and you really don't need to. A good practice is to start around 800ns and start reducing the gate resistor from there. You should only switch as fast as you nee...
by zombiess
Jun 21 2018 11:41am
Forum: Motor Technology
Topic: Building a 100% DIY ESC for motors
Replies: 34
Views: 2024

Re: Building a 100% DIY ESC for motors

The conduction losses are the primary source of heat and only depend on current. Switching losses will go up with voltage. Overall, you won't see much change with higher voltage unless your switching times are too slow. I^2*R loses are dominant at high duty cycle, but at low DC Vds (diode) loses do...
by zombiess
Jan 16 2018 6:26pm
Forum: Motor Technology
Topic: Power PCB for Lebowski Controller to be combined with Bobc's processor board
Replies: 166
Views: 12289

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

10cm is not an issue for gate drive as long as it is over the proper ground plane (not possible on current design). Another possible compromise is to use twisted pair for your gate drive and eliminate the traces all together. The twisted pair will be much less likely to experience ringing. It also h...
by zombiess
Dec 21 2017 7:57pm
Forum: Motor Technology
Topic: Time for MORE POWER! 1400a 1200v IGBT controller build!
Replies: 59
Views: 5561

Re: Time for MORE POWER! 1400a 1200v IGBT controller build!

One thing to keep in mind if you do not try to cancel these fields is you will become an intentional radiator. It doesn't look like it would take much to include a overlapping bus design while keeping that same style layout. Caps would most likely need to go on a carrier board with mechanical connec...
by zombiess
Dec 21 2017 6:24pm
Forum: Motor Technology
Topic: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp p15
Replies: 536
Views: 70911

Re: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp p15

When I read about how they heat stuff I started wondering if they warm up the IGBTs to get them into their positive temp coefficient operating area. Something I've thought about doing previously when I finally jump to paralleling IGBTs vs MOSFETs.
by zombiess
Oct 17 2017 11:00pm
Forum: Motor Technology
Topic: Micro Lebowski Controller - DIY 3kw
Replies: 496
Views: 43267

Re: Micro Lebowski Controller - DIY 3kw

No leboski your numbers are overly optimistic. Truth is you forgot the sag... Likely a 100v battery will sag to 90v under load. Also you will never get a 100v fet to survive at its limits with a 100v battery. The numbers for this would be 84v absolute max fully charged and that will sag to ~75v und...
by zombiess
Aug 24 2017 10:15pm
Forum: Motor Technology
Topic: GaN Mosfet --- Arlo?
Replies: 9
Views: 1055

Re: GaN Mosfet --- Arlo?

They turn on and off with RF level speeds. This sounds like a nice idea, but makes them a bit of a challenge to control in practice. I went to an IEEE presentation on High Electron Mobility Transistors (GaN) devices a while back. After the presentation I was speaking with one of the people that doe...
by zombiess
Aug 24 2017 9:49pm
Forum: Motor Technology
Topic: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp p15
Replies: 536
Views: 70911

Re: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp

The inertia run issue was most likely due to the dyno control loop and the your motor drive control loop finding an unfortunate resonance with each other. I wouldn't be surprised if your motor drive can respond much faster to load changes than a dyno typically used for ICE cars (it might not have en...
by zombiess
Jul 11 2017 3:05pm
Forum: Motor Technology
Topic: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp p15
Replies: 536
Views: 70911

Re: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp

Are you on bias play tires "slicks" or radials? Curious as a drag radial would also give you a little more MPH. Traction is all about suspension setup, read up on what the fast FWD guys are doing and adapt it to your setup.
by zombiess
Jul 11 2017 12:31am
Forum: Motor Technology
Topic: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp p15
Replies: 536
Views: 70911

Re: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp

When you get your 60's down the MPH will come up as well since they are really bad right now. It has really good MPH already which is what really shows the power (i've seen several 13 sec 130MPH passes on Supra's and Civics).

Congrats!
by zombiess
Apr 12 2017 3:24pm
Forum: Motor Technology
Topic: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp p15
Replies: 536
Views: 70911

Re: Hi power high voltage inverter build for nissan leaf mot

Had to convert the part of the chip dealing with impedances to floating point (hand-made floating point as the chip has no hardware floating point). So far it has added 1200 lines of (assembly) code, I expect to need another few 100. Rom is at 94% full now... Are you going to port the code to a pro...
by zombiess
Mar 20 2017 3:39pm
Forum: E-Bike Reviews & Testing
Topic: Sabvoton SVMC072150 controller review, variable regen *PICS*
Replies: 288
Views: 44658

Re: Sabvoton SVMC072150 controller review, variable regen *P

I have a modded 72150 sabvoton that has been unlocked to do 200A. I was wondering if there is a way to do slide regen and brake/button regan. that way I would have two levels of regen. One to slowly stop me and another the stop me much faster. P.S. aliexpress has my modded controller for $275. Tota...
by zombiess
Jan 13 2017 11:16am
Forum: Motor Technology
Topic: OSHW TO247 IGBT watercooled laminated half-bridge
Replies: 144
Views: 17109

Re: OSHW TO247 IGBT watercooled laminated half-bridge

How are you making the DC link capacitor connection to the copper bus and the power devices? I've always found this to be somewhat challenging. I have proper soldering tools that allow me to solder to thick copper bus, but this technique does not seem good for production. I'm interested to see what ...
by zombiess
Jan 10 2017 4:52pm
Forum: Motor Technology
Topic: OSHW TO247 IGBT watercooled laminated half-bridge
Replies: 144
Views: 17109

Re: OSHW TO247 IGBT watercooled laminated half-bridge

That is funny right there. I wonder if the marketing department reviewed the datasheet and modified a few things to improve sales. Reminds me of one of my favorite jokes: “Milk production at a dairy farm was low, so a farmer wrote to the local university to ask for help. A multidisciplinary team of ...
by zombiess
Jan 04 2017 8:53pm
Forum: Motor Technology
Topic: OSHW TO247 IGBT watercooled laminated half-bridge
Replies: 144
Views: 17109

Re: OSHW TO247 IGBT watercooled laminated half-bridge

marcos wrote: Vishay sells an equally magic 2512 6W* resistor.
* = 6W rating only valid on 0 ohm values :mrgreen:
by zombiess
Jan 03 2017 9:55am
Forum: Motor Technology
Topic: OSHW TO247 IGBT watercooled laminated half-bridge
Replies: 144
Views: 17109

Re: OSHW TO247 IGBT watercooled laminated half-bridge

Since resistor inductance and wattage are possible issues, why not place 3 in parallel? Populate them all so the inductance drops and wattage dissipation increases. I like the 2512 footprint myself for its large surface area (thermal management). Of course this depends on space available, but the bo...
by zombiess
Dec 26 2016 10:51pm
Forum: Motor Technology
Topic: OSHW TO247 IGBT watercooled laminated half-bridge
Replies: 144
Views: 17109

Re: OSHW TO247 IGBT watercooled laminated half-bridge

Lockout = preventing the adjacent side from tuning on if one side is active, i.e. when the high side is active, the low side is locked out from turning on. Not sure why you need the logic gates myself or how they would interfere with the differential signal, but personally I would leave the driver c...
by zombiess
Dec 26 2016 1:44am
Forum: Motor Technology
Topic: OSHW TO247 IGBT watercooled laminated half-bridge
Replies: 144
Views: 17109

Re: OSHW TO247 IGBT watercooled laminated half-bridge

Marcos, I believe the reason for the external circuitry is to address a fault before it occurs. It seems more relevant to a design that uses separate High/Low gate drives vs one that has them both integrated into a single chip that has a lockout type function. Highhopes also uses that input techniqu...
by zombiess
Dec 14 2016 2:20pm
Forum: Motor Technology
Topic: OSHW TO247 IGBT watercooled laminated half-bridge
Replies: 144
Views: 17109

Re: OSHW TO247 IGBT watercooled laminated half-bridge

not sure what you mean. we program for 21kHz instead of 20 kHz. or 18kHz instead of 20khz. 18, 21 .. both evenly divisible by 3. so your question is will the processor be stressed if it tries to generate a 21kHz frame rate as compared to a 20kHz. or 18khz as compared to 20khz. so here we are talkin...
by zombiess
Dec 13 2016 12:03am
Forum: Motor Technology
Topic: OSHW TO247 IGBT watercooled laminated half-bridge
Replies: 144
Views: 17109

Re: OSHW TO247 IGBT watercooled laminated half-bridge

HighHopes wrote: you mean 21kHz. keep the switching frequency as a value evenly divisible by 3 and this will magic out some harmonics
In order to do this, wouldn't the PWM need to be generated with 1Hz accuracy? That could be asking a lot from the controller.
by zombiess
Dec 10 2016 12:57pm
Forum: Motor Technology
Topic: OSHW TO247 IGBT watercooled laminated half-bridge
Replies: 144
Views: 17109

Re: OSHW TO247 IGBT watercooled laminated half-bridge

Oh, okay okay, I'll keep that in mind. Battery pack is not laid out yet. To avoid what Njay is referencing (great point Njay!) you must keep the batt to controller leads as short as possible (reduces stray L) minimize their loop area. Inductance + loop area = the enemy, at least from battery to con...