Thanks for the link, it was a really good read. The mechanical design of
the tuning is incredible. In a design I'm currently testing, I'm
implementing a phase lead using an all pass filter (can be tuned with a
potentiometer), so we should be able to get the same results as adding a
series inductor with the burden resistor. However, I've had some issues
getting it working properly. Our control scheme has two current
transformers on the primary, one of which is burdened with a resistor
(for
measuring current) and the other is burdened with clamping diodes (only
for
zero-crossing detection). When detecting the clamped-diode crossings,
the
thing works fine, but when I try to have it trigger off of the burden
resistor waveform, it always starts oscillating at a very high frequency,
causing everything to freak out (not fatally, though).