Passive Filters for High Power Cycloconverter Grinding Mill Drives

Abstract

This paper presents a design method for passive filters used to compensate power factor and current harmonics generated by high power cycloconverter drives. The paper includes the analysis of different passive filter topologies effectiveness (band-pass, high-pass and C type), a procedure to calculate filter parameters, tuning frequency selection, and reactive power distribution. The passive filters are designed to compensate high power grinding mill drives energized from cycloconverters. Simulated results based on a real grinding mill plant prove the effectiveness of the proposed method.

Current harmonics compensation for electrolytic processes using a series active scheme

“…Passive filters composed of different branches must distribute the required reactive power generated by each branch. In general, passive filters include dedicated low-order harmonic filters with reactive power compensation capacity, even when multi-pulse arrangements of step-down transformers are used [1][2][3]. These filters are also used to avoid low-frequency resonances, which can cause magnetic saturation in the step-down transformer core.…”

Harmonic assessment‐based adjusted current total harmonic distortion

“…. , a n = I n I 1 (22) where I 1 is the fundamental component of the current and α 1 , …, α n represent the nth per-unit HS of the current. Accordingly, substituting α 1 , …, α n in (21) we can find…”

“…Q 1 is the fundamental reactive power needed to improve the DPF to an acceptable value, f 1 is the fundamental frequency, and m is a damping factor varies between 1 and 20 [21,22]. It should be noted that the capability of damping resonance increases as m decreases…”

“…On the basis of [21][22][23][24], sizing of the C-type filters' parameters can be introduced as given in (26)- (29), respectively, where h is the filter tuning number. Q 1 is the fundamental reactive power needed to improve the DPF to an acceptable value, f 1 is the fundamental frequency, and m is a damping factor varies between 1 and 20 [21,22].…”

“…Besides, it guarantees adequate high-pass filtering for high-order harmonics with reasonable attenuation of low-order harmonic frequencies [19][20][21][22][23][24][25] and it has low-power loss compared with the other typical passive filter configurations. Accordingly, in this paper, an optimal C-type passive filter design for a typical balanced industrial system that involves a group of linear and non-linear loads, cables, and a distribution transformer, working under non-sinusoidal conditions because of harmonic currents and background harmonic voltage distortion, is proposed.…”