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by zombiess
Jan 02 2021 3:27pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4412

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: 4412

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: 4412

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: 4412

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: 4412

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: 4412

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: 4412

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: 102
Views: 5479

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: 4412

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: 102
Views: 5479

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: 102
Views: 5479

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...
by zombiess
Oct 31 2020 12:10pm
Forum: Motor Technology
Topic: New ground-up ESC - MESC_FOC_ESC
Replies: 102
Views: 5479

Re: New ground-up ESC - MESC_FOC_ESC

The devices I mentioned above were IRFB4115 and an IPP051N15N5, current was DC. The amount of current usable is of course thermally limited. IMO the amount doesn't matter as much as the differences between devices and the correlations in temperature found. I was able to gain enough data to make a us...
by zombiess
Oct 30 2020 3:58pm
Forum: Motor Technology
Topic: New ground-up ESC - MESC_FOC_ESC
Replies: 102
Views: 5479

Re: New ground-up ESC - MESC_FOC_ESC

XT90 I think is overkill, 60A at ~60V is ~3.6kW, which if continuous would launch my ebike to the moon. Surge capacity I imagine is higher, so short term getting 5kW through XT60 seems realistic, and given the visual look of the FET legs compared to the XT60, I know which I am betting on burning fi...
by zombiess
Oct 23 2020 5:35pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4412

Re: Gate driver design with TD350E

When assembling second phase I will experiment with different gate resistors(SMD) to extend fet switching time and maybe this Vds oscillation with PP caps would be smaller. I have not seen the low frequency oscillation change much by altering switching speed as it's mainly tied to the DC bus induct...
by zombiess
Oct 23 2020 8:49am
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4412

Re: Gate driver design with TD350E

I'd use that last setup with just the 330uF as it has the best waveform and try to improve the layout on the next revision now.
by zombiess
Oct 22 2020 10:28am
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4412

Re: Gate driver design with TD350E

What does it looks like when you remover the 2.2uF? I've seen additional caps cause oscillation as they can form another LC tank circuit.
by zombiess
Oct 16 2020 8:50am
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4412

Re: Gate driver design with TD350E

My Rogowaki setup is from Athena Energy who appears to now be out of business. The probes i have can . measure up to 220A and have a bandwidth of 30MHz. They also cost about $1k usd and I have two for doing parallel device research. Totally worth it imo, but I'm obsessed with high current and parall...
by zombiess
Oct 09 2020 12:05pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4412

Re: Gate driver design with TD350E

I also came across a potential nice alternative for the TD350E. with all the bell and whistle : infineon EiceDRIVER™ 1ED38x0Mc12M or simpler one 1ED3122MU12H Looks nice I will order and try this simpler one. Take a look also on STGAP2S from st. I allready make a pcbs and plan is to test it as soon ...
by zombiess
Oct 06 2020 8:47am
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4412

Re: Gate driver design with TD350E

squeegee wrote:
Oct 04 2020 6:55pm
So I can't help wondering why the convoluted bus shape of the inner layers.
Why, for example, is the bat- in the second yellow layer not underneath the read bat- on the upper layer?
It's an old design and not laid out in an optimal way.
by zombiess
Oct 02 2020 11:03am
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4412

Re: Gate driver design with TD350E

Very nice!! You used RS232 for communication with Labview at what speed? Did you had any issues with communication concerning noise from switching? And what about added caps polyprop or electrolytics? Labview setup was something Joby Aviation had for controller testing and that the other guy in the...
by zombiess
Oct 01 2020 8:41pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4412

Re: Gate driver design with TD350E

I hope so :) For this older design did you specify custom core, prepreg, thickness and distance between layers? I couldn’t find this information from board in KiCad. Also this depends of manufacturer. I am using JLCPCB but they have only two options for 4 layers boards and offering some inductance ...
by zombiess
Oct 01 2020 9:29am
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4412

Re: Gate driver design with TD350E

PCB should work as it previously worked for me. My new designs use a better layout, but i have not shared them. I've moved to 6 layer PCBs and can obtain low inductance <20nH. That PCB was a compromise to allow installation of 12mm x 6mm copper bussing in a side by side config. It supported +100A DC.
by zombiess
Sep 29 2020 4:59pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4412

Re: Gate driver design with TD350E

I always enjoy watching desat do it's job, i just don't like to see it trigger in use. I've had it save my controllers during tuning, especially when the controller loses sync at high current. It just takes time to go through and test different fault conditions and dial everything in.
by zombiess
Sep 16 2020 11:37am
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4412

Re: Gate driver design with TD350E

I have found i usually end up with a zener around 5.1V for MOSFETs between 5-10mOhm. I suggest you start with a higher value though. This way desat triggers at a lower current so you can become more familiar with it. When you do order parts, order an assortment. I keep a selection of low value 2512 ...
by zombiess
Sep 11 2020 3:03pm
Forum: Motor Technology
Topic: Gate driver design with TD350E
Replies: 69
Views: 4412

Re: Gate driver design with TD350E

Thanks for pushing me :) I see big benefit of last test. Yes next I will go with desat. First to read again as there is lot of info here about desat(and calculations) and then will follow your recommendations. I'm glad to see you think it is worth while. I know it's a bit confusing at first. A doub...