EPC

[EPC011]

I would like to buy an EUC but only one thing worries me: the unreliability of the MOSFET.
I'm not afraid of leaning and falling because of my mistake. What worries me, when I read advice on how to avoid breakdowns is "don't drive on half battery uphill". That's exactly what I need EUC for: sufficient (not excessive) range and uphill driving.

What I think is the main cause of MOSFET failure is generally poor design and even immature technology. I'm honestly not interested in "my brother drove", "I drove", but I'm interested in someone who is an expert in electric drive and electronic engine management explaining what the problem actually is and why it can't be solved.

MOSFETs as well as IGBTs have been around for a long time in industry and drive large machines. How is it possible that a reliable drive cannot be made? 

The man picks up the EUC, shakes it back and forth and the engine dies instantly. 

When someone asks a question about it, they get answers like: "There is no set EUC", "you are too paranoid", "don't drive uphill for a long time"... So, you have a machine with almost 10kW and 160 Nm of torque, and you are not allowed to drive it uphill?

So, I'm asking an electrical engineer, or an electric motor drive expert, to explain why it's impossible to make oversized, temperature-stable motherboards and MOSFET cooling?

[alcatraz]

It isn't impossible. Euc's are still fairly new and unregulated and all out of china. It means that you have low production companies doing the research.

The good news is that they're safer than they've ever been, today, and continue to improve.

You can definitely ride uphill. Your available torque output kind of follows the state of charge after you drop below ~50% (earlier on smaller wheels, later on bigger). That's why, mostly in the past, going uphill (torque demanding) is when people have had overleans (falls).

Then there are cutouts (often mosfet failures). They can happen for many reasons. You should study electric motors and hall sensors to understand why. Vibrations can over time screw up the hardware that the controller needs to properly switch the mosfets (to prevent burnout). In any case, regular inspection is needed to ensure that everything is bolted down solid, no cracks, and that the mosfets are cooled properly (bolted down into heatsink, fans working).

So reliable euc is still a bit DIY to this day. 

[Dan Cobar]

On 3/27/2024 at 8:16 AM, EPC011 said:

How is it possible that a reliable drive cannot be made?

It comes down to money. 

The Rivian RT1 has 6 MOSFETS per motor.  While EUCs have 12 or 24 or who knows how many.  If they used the right kind, they would be reliable with only 6 MOSFETs.

They would cost a little more though.

[Dan Cobar]

On 3/27/2024 at 8:16 AM, EPC011 said:

"don't drive uphill for a long time"... So, you have a machine with almost 10kW and 160 Nm of torque, and you are not allowed to drive it uphill?

This is a cooling issue.  If you have good forced air cooling on a proper sized heat sink, it should be fine.   But we also want water resistance too.  So we can't have exposed mainbord.  This limits the ability to air cool the MOSFETs/heatsink.