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fix(current sense): swap the measured currents, not a variable with itself - #573
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stijncarelsbergh wants to merge 1 commit into
Open
stijncarelsbergh wants to merge 1 commit into
stijncarelsbergh wants to merge 1 commit into
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…tself The alignment routine relabels the pins when the highest current was measured on another channel, but the corresponding sample swap was written as `_swap(c_a.b, c_a.b)` - a no-op. The polarity check that follows (`_sign(c_a.a) < 0`) therefore inspects the sample of the wrong channel and can invert the gain of the phase it just repaired, which turns the current feedback into positive feedback at low currents. Also fixed the same pattern in the 'A-(C)NC' branch, which swapped c_a.b with c_a.c while the pins swapped were A and C. Reported in the alignment audit; trigger is exactly the miswiring this feature exists to correct.
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fix(current sense): swap the measured currents, not a variable with itself
The alignment routine relabels the pins when the highest current was measured on
another channel, but the corresponding sample swap was written as
_swap(c_a.b, c_a.b)- a no-op. The polarity check that follows(
_sign(c_a.a) < 0) therefore inspects the sample of the wrong channel and caninvert the gain of the phase it just repaired, which turns the current feedback
into positive feedback at low currents.
Also fixed the same pattern in the 'A-(C)NC' branch, which swapped c_a.b with
c_a.c while the pins swapped were A and C.
Reported in the alignment audit; trigger is exactly the miswiring this feature
exists to correct.
Split out of #571 at your request: one fix per PR, against
dev. The branch containsnothing else, so it can be reviewed, amended or dropped on its own.
The CI board matrix runs automatically; I did not run any hardware test, so the behavioural
claims are from reading the code plus the compiler. Happy to adjust the wording, split it
differently or drop it - no attachment to this one.