I was just wondering if a(n) inductor (being used to filter AC) could interfere with a PWM signal?
Yes, an inductor will definitely have an effect on a PWM signal.
Using Fourier analysis, a PWM signal can be broken down into series of sine waves. Thus inductor will exhibit an impedance to PWM signal.
PWM is pulse width modulation. Your electrical device tries to make square waves of different wavelength. A metaphor for this is opening the door. An inductor resists change. It is a short to DC but to AC acts like a resistor. A metaphor for this is tying a very large weight to the door. So you have a kid playing in the house. They open the door exactly when your system would switch the pwm on, and they close it when the system would switch it to off. Now imagine tying successively larger weights to the door and looking at how it behaves. When it has zero weight, it opens and closes exactly how the kid (pwm controller) wants it to. As you add weight it opens more slowly, and closes more slowly. Initially this makes your waves a little saw-tooth instead of square. As the mass increases, this cuts off your systems bandwidth. If the kid wants to open and close it quickly - they cannot. Its lag is so bad that high-frequency switching cannot occur. Could you tie your PWM into a hi-lo driver or some configuration of FETs where the two year old kid is replaced with a bigger person aka your switch can force the mass of the door open? Can you reduce the need for the inductance? Opto-isolators can be useful if you are trying to separate systems where one could harm the other. Be careful to validate that they work across the spectrum they are supposed to - they do not always perform to manufacturers documentation. Best of luck.
