Inductive filter vs capacitive filter: Which is better and gives less THD on the input side


I have a generalised statement that total harmonic distortion (THD) on input side for input supply current is more for single phase diode rectifier with capacitive filter as compared to single phase rectifier with inductive filter. How is an inductive filter better than a capacitive filter in this context ?

Best Answer

You need to specify exactly what circuit you mean when you say inductive filter and capacitive filter. Most likely your inductive filter has a capacitor in there too. It's hard to imagine a single diode rectifier to make DC and not putting a cap across is somewhere. If the inductor is therfore in addition to the cap, the additional filtering will additionally reduce high frequencies, which reduces the harmonics, and therfore the total distortion on the output.

Perhaps the statement is referring to THD of the current waveform on the input. In that case a inductor in series will spread out the current over time instead of it being drawn in short spikes shortly around the input peaks.

Again, you need to specify more clearly what you are asking about to get a more accurate answer.

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