Active Compensation of Sub and Interharmonics in Cycloconverter-Fed Grinding Mill Drives

This paper presents a filter scheme implemented with passive high-pass filters and a shunt active power filter. The filter scheme is aimed to compensate high power cycloconverter drives used in grinding mill plant. Passive filters are used to compensate power factor and characteristics current harmonic components generated by the cycloconverter, while the shunt active filter is designed to compensate only the low frequency sub and inter-harmonics generated by the cycloconverter. The principal advantage of the proposed scheme is that it allows effective attenuation of all the harmonic components resulting from cycloconverter input currents, meeting IEEE Std. 519. Simulated results of a large grinding mill plant compensated with the proposed filter scheme prove the compensation effectiveness.