Guru
Joined: 13/10/2014
Location: AustraliaPosts: 1860
| Posted: 10:06am 26 May 2023 |
I was going over the peak DC input current testing I did the other day, I noticed something interesting when comparing the recordings of two chokes compared to one choke:
One Choke: Notice the different peak current in each cycle of DC current [Yellow Trace]
The inverter is drawing slightly more current producing one half of the AC cycle compared to the other, this is likely due to having only one choke in one side.
The smooth ramp up in current to 520A is likely due to the 10 Stack toriod choke and it not saturating even at 520A, it still has some inductance past 600A.
There is also more current being drawn over the first few cycles with only one choke, there is now half the inductance and some winding resistance (R-LOSS) removed for good measure.
Below - Two Chokes: A small amount of variation, the Hybrid choke E-Core is totally saturated past 100A and the 16uH Toriod ring choke is close to full saturation, there is less initial startup current for the first few cycles, more initial inductance of two chokes and some extra R-Loss thrown are the reasons.
I need to test this correctly when I split the 10 stack choke into one half in each leg. I have decided to use 7 cores in each half, I can use a turn or two less and have slightly higher saturation as well, meaning a little more inductance in reserve at 520A "plus" current peaks.
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