[MattsAwesomeStuff]

I've probably missed it somewhere, but, I presume this is only the brains for a controller. The actual power stage is something that'll be done elsewhere or can be reused from some OEM parts?

 

[Tony Bogs]

Yep, the title indicates "Tesla", in particular the FDU "S" drivetrain, but it is also intended for use in combination with the all SiC power stage.

There's no hurry, as is obvious from my late response, but I'll continue to evaluate DIY practices and methods. And design circuits for own projects.

For instance: a precharge sensor circuit that consists of a zener in series with an optocoupler (thyristor output) has a serious temperature range issue and it may become unreliable without a gate resistor to ground at the thyristor output.
No gate resistor is considered to be bad design practice.

But right now I'm kind of 24/7 busy with more important stuff.


And I'm waiting for the first intrinsicly safe high energy (solid state) batteries to hit the market in volume. Those Tesla ones and NMC811 are pretty safe in a mainstream production EVs, but in a DIY build?

 

[arber333]

Hi

Here is one voltage sense circuit, courtesy of Arlo
https://endless-sphere.com/forums/viewtopic.php?f=30&t=36602&start=1775#p1500561

And another from Johannes
https://openinverter.org/wiki/File:Schematic_voltage_sense_board.png

You can even test older AT Tiny chip oscilator design version.
https://openinverter.org/wiki/File:Schematic_sensor_board_r3.png
I tested them both.

 

[Tony Bogs]

Well, I saw one on github, posted in april 2019. What a crappy design, but I must admit it is simple.
Really crappy, so I'm not going to post a link. I like the guy.

I'm not doing voltage sensing, have you seen my design?

Apparently, a more basic (read: inexpensive, build on a shoestring) approach might be appreciated.
So it's coming. Automatic precharge, uC free, basic version. All voltages up to 1000V.

 

[arber333]

So it's coming. Automatic precharge, uC free, basic version. All voltages up to 1000V.

What about voltage divider and TL431 diode with opto across barrier?

 

[Tony Bogs]

Yeah, what about it?



I have taken my original 77 thyristor design into this millenium. Smart mos output for instance. At the same time I have integrated automatic discharge.



No diagram. I hate it when someone else builds my design before I have the chance.

 

[Tony Bogs]

The section of the automatic precharge circuit that senses current. Similar to the real deal.
And the small signal equivalent (bode plotter simulation) for AC analysis.

 

[Tony Bogs]

Basic, basic, basic .... auto discharge & precharge, suitable for uC (tesla FDU &SiC) and the basic uC free DC (LTC69xx).


OFF TOPIC of course....

 

[Tony Bogs]

Hardware implementation of pre- and discharge to minimize coding effort.
It also makes it a lot easier to handle the HV circuits.

I've added a few parts. Description (this is the 1000V version):

1. A high precharge current must have occured. This triggers U3.
2. The precharge current must drop to a low value. If not, Q2 blocks activation of the output.
3. The precharge current may not become zero or very low (indicates a possible open circuit).
U4 disables output stage at very low current levels.
4. The integrated discharge network (R2) garantuees a minimum current at the CAP+ terminal for the detection of open circuit.
5. Thermistor TH1 provides compensation for thermal variation (mainly CTR).
6. Zener D3 creates a threshold for UVLO.

First try: solder it on an experiment board.

 

[Tony Bogs]

Of course there's no thermistor to compensate for CTR.


@arber333 asked:

How about TL431?

Answer: Not V, but I sensing.

Here's the DC step analysis of the mosfet bypass input stage (IRF1018E, Infineon model)
at 200V input, 100R precharge.

 

[Tony Bogs]

KiCAD eye candy of the 25A precharge, 10A discharge module.