A new Equivalent Circuit to Harmonic Currents on the AC side of Diode Rectifiers.

Converters or rectifiers using semiconductor switching devices generate harmonics caused by the behavior of switching. Harmonic currents generated by a rectifier are almost constant even if a source impedance varies, because the impedance on the dc side is much larger than the source impedance on the ac side. Therefore, the equivalent circuit of the rectifier can be considered as an ideal current source for harmonics. However, the theoretical derivation of the equivalent circuit has not been reported as long as the authors know.In this paper, some problems of the conventional equivalent circuit are pointed out, and a new equivalent circuit of the rectifier for harmonics which can solve the problems of the convenional equivalent circuit is derived theoretically. As a result, the applicable limitation of the new equivalent circuit is revealed quantitatively. To clarify the validity of the new equivalent circuit, it is appied to the analysis of anti-resonance between the source impedance and the LC filter connected on the ac side of a rectifier. An accurate explanation of the harmonic amplification in the source is done by using the new equivalent circuit proposed in this paper.