Search found 2929 matches

by zombiess
Jun 12 2021 6:56pm
Forum: Motor Technology
Topic: Non-silicon and/or soft-switched controller topologies?
Replies: 49
Views: 909

Re: Non-silicon and/or soft-switched controller topologies?

As far as shoot through is concerned, what's your recommended way for detecting and surviving that? I figured that bus input current would spike and you'd see it on the DC bus, but I don't know if that would be fast enough to save everything. A gate drive which is able to detect it and take action....
by zombiess
Jun 12 2021 12:39pm
Forum: Motor Technology
Topic: Non-silicon and/or soft-switched controller topologies?
Replies: 49
Views: 909

Re: Non-silicon and/or soft-switched controller topologies?

Darn it. My exploration into GaN is being thwarted because Coss losses dominate my device selection. My current Si part works better than most parts I'm finding.
by zombiess
Jun 12 2021 11:17am
Forum: Motor Technology
Topic: Non-silicon and/or soft-switched controller topologies?
Replies: 49
Views: 909

Re: Non-silicon and/or soft-switched controller topologies?

If you follow zombiess advice, you'll definitely end up with something that works well and reliably. He does this for money I believe, he has a strong interest in making things that work and don't fail. But that's not much interest to me. I would rather see you fail and learn a whole load than succ...
by zombiess
Jun 11 2021 11:04am
Forum: Motor Technology
Topic: Non-silicon and/or soft-switched controller topologies?
Replies: 49
Views: 909

Re: Non-silicon and/or soft-switched controller topologies?

Honestly, I'm using GaN and high Fsw as much to get the hang of working with GaN and high-frequency switching for future power converter designs as anything else; I also am really interested in using an Emrax motor to build an EV with, but the resistance and inductance are low enough that I assume ...
by zombiess
Jun 10 2021 11:43pm
Forum: Motor Technology
Topic: Non-silicon and/or soft-switched controller topologies?
Replies: 49
Views: 909

Re: Non-silicon and/or soft-switched controller topologies?

Thanks! Completely unrelated question; what bit depth did you use for PWM on your custom controller, and what's the minimum bit depth you recommend? The Zynq platform I'm looking to use to do the control design on has a maximum clock speed of 780 MHz if I buy the high-speed grade parts; if I want 2...
by zombiess
Jun 10 2021 6:03pm
Forum: Motor Technology
Topic: Non-silicon and/or soft-switched controller topologies?
Replies: 49
Views: 909

Re: Non-silicon and/or soft-switched controller topologies?

Quick question; did you get those numbers with an external heatsink on the transistors you were switching? That is the one really annoying thing about SMT power parts; the heat path into the board is often the best path for device heat. I'm kind of tempted to try to make a heat pipe to sit on top o...
by zombiess
Jun 10 2021 12:46pm
Forum: Motor Technology
Topic: Non-silicon and/or soft-switched controller topologies?
Replies: 49
Views: 909

Re: Non-silicon and/or soft-switched controller topologies?

I've done a lot of empirical testing on power dissipation in PCBs for my own designs and I'm pretty sure you will need to reduce your power dissipation to work at the size you are talking about, or figure out a better way to get rid of the heat / produce less of it. I've found that a 4 layer 1.2mm t...
by zombiess
Jun 09 2021 2:11pm
Forum: Motor Technology
Topic: Non-silicon and/or soft-switched controller topologies?
Replies: 49
Views: 909

Re: Non-silicon and/or soft-switched controller topologies?

Thanks for the advice! I found the old thread about distributed controllers from 2014 where laminated busbars and the details of how to do clever low-inductance things came up (https://endless-sphere.com/forums/viewtopic.php?f=30&t=55641), and reorienting the half bridges slightly and using lam...
by zombiess
Mar 29 2021 6:19am
Forum: Motor Technology
Topic: New ground-up ESC - MESC_FOC_ESC
Replies: 161
Views: 8656

Re: New ground-up ESC - MESC_FOC_ESC

I'm curious to see how well it performs thermally. I've worked with some power SO8 devices in SMPS designs and found thermal management to be challenging when using a PCB as a heat transfer medium. I could only manage about 5W of waste heat produced mostly by 2x SO8's on a 45x45mm board area with a ...
by zombiess
Mar 19 2021 4:57pm
Forum: Motor Technology
Topic: New ground-up ESC - MESC_FOC_ESC
Replies: 161
Views: 8656

Re: New ground-up ESC - MESC_FOC_ESC

External Cgs is a very strong tool against miller. I use it most of the time, and always place the footprint. Just keep in mind the extra avg current on the gate driver and that the cap tolerance is really bad compared to the typ 1% resistor. I also agree adding some Cgs can work wonders, but it ca...
by zombiess
Mar 08 2021 1:02am
Forum: Motor Technology
Topic: 10kW BLDC motor controller up to 90V and 200A with sensorless FOC - build thread
Replies: 63
Views: 3075

Re: 10kW BLDC motor controller up to 90V and 200A with sensorless FOC - build thread

Peters, you did a nice job working with only 2 layers. My first design was only 2 layers and with parallel devices it was a mess to figure out. Did it take you more than one try?
by zombiess
Mar 04 2021 8:05pm
Forum: Motor Technology
Topic: 10kW BLDC motor controller up to 90V and 200A with sensorless FOC - build thread
Replies: 63
Views: 3075

Re: 10kW BLDC motor controller up to 90V and 200A with sensorless FOC - build thread

The gate driver he has detects desat at 6.5V. Peters hasn't said what FETs he's using (has he?) but I'm going to assume that 2to247s have an Rdson of about 1-2mohms. So the desat kicks in at 3-6.5kA. I don't think 1) the FETs will be able to break this current 2) his battery can supply that current...
by zombiess
Mar 04 2021 2:11pm
Forum: Motor Technology
Topic: 10kW BLDC motor controller up to 90V and 200A with sensorless FOC - build thread
Replies: 63
Views: 3075

Re: 10kW BLDC motor controller up to 90V and 200A with sensorless FOC - build thread

So what do we actually expect to cause desat of these MOSFETs? I'm 100% behind: Over current Over voltage (though this seems routinely overlooked despite being the single biggest cause of FET death) Shoot through protection/hardware dead time Fuses before the ESC Inrush limiters Défensive coding Wa...
by zombiess
Mar 03 2021 11:42am
Forum: Motor Technology
Topic: 10kW BLDC motor controller up to 90V and 200A with sensorless FOC - build thread
Replies: 63
Views: 3075

Re: 10kW BLDC motor controller up to 90V and 200A with sensorless FOC - build thread

I don't understand a lot of the choices, the avago gate drivers with 5kV isolation, IGBT drivers with all the miller desat stuff when you're using MOSFETs, isolation everywhere for 90V... But it's fascinating. It would be really unlucky if it didn't work. Hopefully it's bulletproof This is the way....
by zombiess
Jan 02 2021 3:27pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4918

Re: Gate driver design with TD350E

You've seen in my design how I mounted the gate drive at a 90 myself, so yeah, I approve. It puts the gate drive at a 90 from power pass EMI.

I have not worked with any devices over 200V, so I don't have any recommendations.
by zombiess
Dec 08 2020 7:35pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4918

Re: Gate driver design with TD350E

In original design plane which connects D of one fet and S of other fet (phase) is overlapped with + and - dc bus planes (4 layer pcb) but in stgap2 layout example they used 2 layer pcb and didn't overlapped D-S plane with - dc bus plane nor + dc bus plane. So layouts are done differently. My quest...
by zombiess
Dec 07 2020 8:01pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4918

Re: Gate driver design with TD350E

Looking at original design. design.JPG Seems that on high fet gate signal passes above power section common node forming S from high fet and D from low fet. On low fet, gate signal passes above - dc bus. Doing double pulse tests separately on high and low fet I noticed little differences in gate si...
by zombiess
Dec 07 2020 7:31pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4918

Re: Gate driver design with TD350E

Okey. I turned on again desaturation detection. Seems that fault pin is floating between 5V(fault pin is connected with resistor to opti diode and then to 5V) and 12V( + power supply of TD350E) but no low level output. Here are waveforms on all 4 fets with probes on fault pin and ground). Could thi...
by zombiess
Nov 27 2020 2:16pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4918

Re: Gate driver design with TD350E

Is it possible to share some of your sim models :)? I won't share them, it takes quite a bit of work to learn how to generate these types of signals and that is where the real learning happens. I learned by reading papers similar to the one you posted and replicating the research (start simple). Ye...
by zombiess
Nov 25 2020 7:51pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4918

Re: Gate driver design with TD350E

If you have a time take a look of this document. https://unbscholar.lib.unb.ca/islandora/object/unbscholar%3A9775/datastream/PDF/view 9D242E56-2811-4393-878D-E736BFD4FAC3.png I think it is not issue of switching fets it could be as described here distortion as combination of dead time(during which ...
by zombiess
Nov 24 2020 4:09pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4918

Re: Gate driver design with TD350E

When troubleshooting, it's advantageous to monitor the Vgs vs Vds vs Pulse input if possible. How long does it take to get to at least 8V on Vgs? If this is happening at low duty cycle, you might be switching too slowly to get the MOSFET into saturation. 27 Ohms coupled with a 55nF G-S resistor seem...
by zombiess
Nov 07 2020 2:02pm
Forum: Motor Technology
Topic: New ground-up ESC - MESC_FOC_ESC
Replies: 161
Views: 8656

Re: New ground-up ESC - MESC_FOC_ESC

That's not unusual if you get low loop area. I've done 100's of amps in 70-100ns with similar results, but I always slow it down to improve reliability. Fast edges will often lead to noise coupling into other stuff. I do a lot of paralleling of devices, and fast switching has shown worse current sha...
by zombiess
Nov 06 2020 6:05pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4918

Re: Gate driver design with TD350E

But what about high fet Vds overshoot and how did you handled? Do you have shoots and can you post here? All changes were made consistent through the design to keep symmetry. What ever was done to either a high/ low side was also done to the other. My high side / low side tests always look about th...
by zombiess
Nov 06 2020 5:39pm
Forum: Motor Technology
Topic: New ground-up ESC - MESC_FOC_ESC
Replies: 161
Views: 8656

Re: New ground-up ESC - MESC_FOC_ESC

100ns is slow compared top the times quoted with the gate resistors and results quoted in the data sheet. Which are roughly what I'm using. Physics is the ultimate rule maker, so one way or the other you'll get answers. I'm going off of personal experience + sage advice from some advanced power ele...
by zombiess
Nov 02 2020 8:19pm
Forum: Motor Technology
Topic: New ground-up ESC - MESC_FOC_ESC
Replies: 161
Views: 8656

Re: New ground-up ESC - MESC_FOC_ESC

say I assume a slow 100ns switch times, 80A80V 35kHz... = ~22W (upper limit) 100ns is not slow, it's pretty fast for a high power device and could cause you some noise issues. Keep in mind you are talking about a 10MHz edge + any other fun stuff it excites. Best practice is to only switch as fast a...