A New Hybrid Filter Topology for Sub and Inter-Harmonic Attenuation in Cycloconverter-Fed Drives Applications

This paper presents a filter scheme composed by passive and series active power filters specially designed to compensate fundamental reactive power (with passive filters) and current harmonics (combination of passive and active). Low frequency current sub and inter-harmonics generated by cycloconverters are eliminated with an active power filter connected in series to a C type passive filter. Current frequency harmonics associated with cycloconverter topology are eliminated with passive filter units. With the proposed filter topology compensation effectiveness is significantly improved and allows the elimination of passive filter units, reducing cost and space required as compared with traditional passive schemes. This paper presents the principles of operation and design requirements of the proposed hybrid filter scheme. Simulated results based in the compensation of a real grinding mill plant prove the effectiveness and advantages of the proposed scheme.