Search found 2799 matches

by zombiess
Sep 19 2019 8:29pm
Forum: Motor Technology
Topic: 100A through a MOSFET? FLIR video
Replies: 1
Views: 232

100A through a MOSFET? FLIR video

This is part of a series of tests I ran to quantify some maximum parameters of various MOSFETs. The one in this video is an IRFP4568. Turns out my setup was able to handle a maximum of about 120W of dissipation. Not going to happen once an insulator is in place, I only managed 66A when it was instal...
by zombiess
Aug 28 2019 1:03am
Forum: Motor Technology
Topic: Hi power inverter for Nissan leaf motor. Dyno's 302.3hp p15
Replies: 575
Views: 88248

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

Any particular reason you want to run 17" rims vs 15 or 16"?
by zombiess
Aug 04 2019 11:56am
Forum: Motor Technology
Topic: MOSFET gate driver ringing causes
Replies: 5
Views: 322

Re: MOSFET gate driver ringing causes

What about snubbers in this situation of ringing? I've had luck implementing snubbers in one of my low power controllers (mainly compensating for bad layout). Can snubbers scale up to high power stuff? There are high power setups using snubbers but it's best to design to avoid snubbers if you can (...
by zombiess
Aug 04 2019 11:30am
Forum: Motor Technology
Topic: MOSFET gate driver ringing causes
Replies: 5
Views: 322

Re: MOSFET gate driver ringing causes

yes, additional capacitors on the DC bus rarely help. The PCB must originally be designed to accommodate all caps with low inductance. My observation was that the new low frequency (660kHz) is the oscillation between the big DC bus cap and the new 1uF, and the high freq (10MHz) is between the 1uF a...
by zombiess
Aug 01 2019 4:51pm
Forum: Motor Technology
Topic: BESC - beefed up VESC motor controller for high power ebikes
Replies: 132
Views: 11790

Re: BESC - beefed up VESC motor controller for high power ebikes

From where do you see it is EMI sensitive, by the gate ringing? By your 475 and 575ns which transitions do you mean exactly, can you show on a waveform? From what you said, I thought you had an EMI compliance issue. The 475ns refers to the time it takes the D-S to switch from 10% to 90% of it's ran...
by zombiess
Aug 01 2019 4:47pm
Forum: Motor Technology
Topic: MOSFET gate driver ringing causes
Replies: 5
Views: 322

MOSFET gate driver ringing causes

We have several designs going on in this forum so I'll share some troubleshooting tips which hopefully aid in the design/construction. There are many issues which crop up when paralleling devices, most of them tie back to layout issues and parasitic inductance. For more details on this topic I sugge...
by zombiess
Jul 31 2019 1:38pm
Forum: Motor Technology
Topic: BESC - beefed up VESC motor controller for high power ebikes
Replies: 132
Views: 11790

Re: BESC - beefed up VESC motor controller for high power ebikes

That's some good info Peters. I too have seen that same oscillation on the miller plateau in some of my previous testing. The way I handled it was to add a larger Cgs cap as you mentioned, and it worked really well in my own application, but my application was not noise sensitive. It appears your ap...
by zombiess
Jul 30 2019 3:48pm
Forum: Motor Technology
Topic: BESC - beefed up VESC motor controller for high power ebikes
Replies: 132
Views: 11790

Re: BESC - beefed up VESC motor controller for high power ebikes

I reckon there are several options: 1. gate driver with desat. This is the most robust protection. The ACPL-33x series is also a choice, functionally similar to ISO5452. I use ACPL-332 nowadays. The difficulty with both of them is that they require 15V power supply, but some FETs operate better at ...
by zombiess
Jul 30 2019 3:26pm
Forum: Motor Technology
Topic: BESC - beefed up VESC motor controller for high power ebikes
Replies: 132
Views: 11790

Re: BESC - beefed up VESC motor controller for high power ebikes

Part you listed is obsolete. :confused: Here is the status of the part from ST micro, says it's still an active part https://www.st.com/en/power-management/td350e.html The reason I'm recommending this gate driver to you is not because it's a top of the line chip, it's because I've fully tested ever...
by zombiess
Jul 28 2019 10:07pm
Forum: Motor Technology
Topic: BESC - beefed up VESC motor controller for high power ebikes
Replies: 132
Views: 11790

Re: BESC - beefed up VESC motor controller for high power ebikes

Search my username and td350, you'll have hours of reading.
by zombiess
Jul 28 2019 12:00pm
Forum: Motor Technology
Topic: BESC - beefed up VESC motor controller for high power ebikes
Replies: 132
Views: 11790

Re: BESC - beefed up VESC motor controller for high power ebikes

galp wrote:
Jul 26 2019 9:19am
IT's this one: http://www.ti.com/lit/ds/symlink/ucc21520.pdf
I would not use that gate driver, it's not suitable for this application as it provides no fault mitigation.
by zombiess
Jul 23 2019 11:20pm
Forum: Motor Technology
Topic: BESC - beefed up VESC motor controller for high power ebikes
Replies: 132
Views: 11790

Re: BESC - beefed up VESC motor controller for high power ebikes

the gate drive signal is crossing through the power pass section which is a pretty big no no For clarification, are you referring to the power pass as the DC bus bars or the switch nodes going to the motor phases? The gate drive traces are passing through both of the these regions. If you are refer...
by zombiess
Jul 23 2019 3:37pm
Forum: Motor Technology
Topic: BESC - beefed up VESC motor controller for high power ebikes
Replies: 132
Views: 11790

Re: BESC - beefed up VESC motor controller for high power ebikes

Personally I think it would be better to route the PWM signal around the power pass section to a separate gate driver on the other side, but I prefer reliability and robustness over ease of design. The gate driver layout is the most critical part of the entire design. If you manage to induce enough ...
by zombiess
Jul 22 2019 6:02pm
Forum: Motor Technology
Topic: BESC - beefed up VESC motor controller for high power ebikes
Replies: 132
Views: 11790

Re: BESC - beefed up VESC motor controller for high power ebikes

It looks like the gate drivers on the bottom of the board and all on one half (high or low side). While this makes for easier construction, it also means the gate drive signal is crossing through the power pass section which is a pretty big no no when attempting high current. While I don't recommend...
by zombiess
Jun 20 2019 6:01pm
Forum: Motor Technology
Topic: Lead current limit for different MOSFET packages?
Replies: 5
Views: 432

Re: Lead current limit for different MOSFET packages?

Stick to 45A rms per device for to-247 and 35A to-220 devices for continuous operation and it "should" be ok based on my own testing. The leg temps tend to be about 10C hotter than when the case temp is 80C (which you don't want to exceed). Keep in mind that when I'm talking about continuous, i real...
by zombiess
Mar 12 2019 10:32am
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 204
Views: 15665

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: 204
Views: 15665

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: 204
Views: 15665

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: 204
Views: 15665

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: 204
Views: 15665

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: 2991

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: 201
Views: 19333

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: 6747

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: 575
Views: 88248

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: 48556

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...