I'm trying to design a filter to reduce the EMI from two H-bridges driving a Peltier element load (also called thermo electric module) with a PWM switching output at 20 kHz. The cut-off frequency of my filter should be approx. 30 kHz, depending on what suitable filter components I can find for the PCB design. I'm experimenting with different filter design tools such as this from Panasonic (https://util01.industrial.panasonic.com/ww/utilities/ds/lc-sim/) and this tool from Marki Microwave (https://rf-tools.com/lc-filter/).
Both of these tools include input and output resistances in the simulation, and I'm trying to figure out what I should include in these resistances.
I'm guessing that as output resistances I should include the resistance of the entire load, both the Peltier elements and the cabling to the Peltier elements. I also assume that I should take the full impedance of the load into account in some way, and not only the resistance? In my specific case the load is 3.7 Ohms, 81 uF and 3.1 uH, measured at a frequency of 10 kHz. The simulators seem to only model the load as a pure resistive load, how would I take the inductance and capacitance of the load and cabling into account?
When it comes to the input resistance I'm a bit more confused though. My guess is that I should take the full resistive path from the power supply that is driving the circuit into account, and not only the path from the H-bridge drivers, is this assumption correct?
In the schematic above I have included a T-filter as a placeholder for now, since this site from Panasonic recommended T-filters when you have both a low input and output resistance (which I believe I have in this case?) https://industrial.panasonic.com/ww/ss/technical/b4