An adaptive shunt hybrid filter for Power quality improvement

Abstract

These days, many power electronic controllers are introduced in association with power system equipment to improve efficiency, reliability and smoothness in operation. These devices introduce harmonics in source currents and hence in source voltages at the point of common coupling (PCC). To mitigate these harmonics, various filters such as passive filters and active filters are researched and developed. Though these filters are extensively used in industries, they have many drawbacks. Passive filters can compensate only tuned harmonic frequencies and provide only partial reactive compensation. Also they are bulky in size and cause resonance. Active filters can completely compensate for harmonics and reactive power. But it accompanies complex control circuits and higher rated circuit components. Also, most of the developed controllers are not effective under unbalanced and dynamic systems. Hence, a new flexible and low rated filtering technique is needed. In this research work, topology, selection of elements and development of effective digital controller based on Artificial Neural Networks(ANN) for the filter configurations ? adaptive shunt passive filter, ANN controlled shunt active filter and adaptive shunt hybrid filter ? are proposed by the author. The adaptive shunt passive filter (variable element passive filter controlled by ANN) is developed by improving reactive power compensation characteristics of the traditional fixed element passive filter. ANN controlled shunt active filter is the structure in which the shunt active filter is controlled by ANN based digital controller. It has merits such as flexibility, reduction in space, adaptability to system conditions and ease in manufacturing in large quantities. Finally, the combination of adaptive shunt passive filter and ANN controlled shunt active filter - adaptive shunt hybrid filter - an effective, flexible and low rated hybrid filter configuration is developed by the author.