this mathcad worksheet is offered to predict the stability of a voltage-sense, current-inject active emi filter (aef) circuit, in particular with respect to ti's tpsf12c1/3/-q1 family of aef ics, and to assist with component selection. the model is inclusive of most parasitc effects and can be used as a quick check of the loop gain and insertion loss prior to simulation, bench measurement and fine tuning.
the worksheet functions for single- and 3-phase ac systems and facilitates two ways of entering the cm choke parameters:
1. using an equivalent circuit model with (a) resistive and capacitive parasitics – suitable for ferrite-core chokes; (b) a ladder network of three parallel rl circuits -- suitable for nanocrystalline chokes
2. using measured impedance data (magnitude and phase).
the worksheet is ideal for knowledge capture, unit-aware calculation reuse and for engineering collaboration amongst design, systems & application engineers.