3-Phase inverter/controller looks too small for 9.3kW

[zenerbjt]

Dear Engineers,
The Flame 180A is a 3-phase inverter and inverter controller for a BLDC. It runs off a 6S or 14S lithium battery (22-52V).
https://store-en.tmotor.com/goods.php?id=733

This video shows it..

There is no documentation with it. (as the video says)

Does the “180A” refer to the average supply current to the inverter from the battery…or does it refer to the peak phase current?

Also, with a 14S, that’s 52Vin, which means at 180A, that’s 9.3kW……just looking at the Flame 180A, it just doesn’t look like a 9.3kW inverter. It looks way too small. Would you agree? (Even with high speed blown air going over it).....see it at 1:32 in the video if you wish

In the video at 1:32 you can see the tiny input capacitor bank…that’s all it is…some 9 capacitors of the size you see there…this surely is nowhere near enough for a 9.3kW 3-phase inverter to a BLDC. I will try and find out the part numbers and do the calcs.

Current measurement:
We’d like to use a 250A unidirectional Allegro-Micro Hall sensor to sense the current from the battery when the Flame 180A is operating.…..
ACS772 Hall current sensor
ACS772ECB-250U-PFF-T
https://www.allegromicro.com/en/Pro...ed-Amp-Integrated-Conductor-Sensor-ICs/ACS772
Do you believe 250A will be big enough to catch the peak of the battery supply current?

 

[betwixt]

It doesn't answer your question but you might be interested in a video of a friend of mine. Everything is home designed and home made, including all the electronics and control systems. His other hobby is collecting gas turbine engines (and running them at home in Bristol UK)! Glad I'm not his neighbour

Brian.

 

[KlausST]

Hi,

Simple calculation:
I = P / V
Drawing 9.3 kW from 22V = 9300W/ 22V = 423A.

Klaus

 

[zenerbjt]

Yes, and does the 180A of the "Flame 180" refer to the input current from the battery?...or the peak phase current in the motor?

 

[KlausST]

Hi,

I don't know, but it looks like the battery current.
Maybe contact the manufacturer...

The motor current depends in a lot of parameters. Mainly the motor voltage. But also phase shift.
Lets say three phases , each has 230V RMS (referenced to star point) and you have a phase current of 10A RMS then the true power may be anything from [- 3 x IRMS x VRMS] to [zero] to [+ 3 x IRMS x VRMS]
.... While in one case the motor acts as generator. You are free to exclude this case.

Btw: for an ideal three phase inverter the drawn power and the drawn battery current should be constant (for constant linear loads, without overtones). This is not the case for single phase systems.

Klaus

 

[zenerbjt]

Maybe contact the manufacturer...

Cheers, the manufacturer of this is known for not having any docs for this inverter...other than the bit thats linked in the top post.
Do you agree that the three inductors of a 3phase BLDC are driven like synchronous buck inductors?
Thus the current sense resistor voltage will look like a train of trapezoids?....(like the buck input current)

 

[KlausST]

Hi,

Do you agree that the three inductors of a 3phase BLDC are driven like synchronous buck inductors?

... at least it comes close to it...

Klaus

 

[zenerbjt]

Thanks, by the way, the eletrolytic input capacitor bank to this 3 phase inverter is 7 pieces of 330uF,63V,105degC.

 

[schmitt trigger]

Without written specs, 180 amps may as well be the current level required for the unit to become critical, and start a spontaneous fission reaction.