Teh Combined System of a Series Active Filter and a Shunt Passive Filter. An Optimum Design of the Shumt Passive Filter.

The combined system of a series active filter and a shunt passive filter has been proposed by the authors. It has the ability to eliminate such a disadvantage of a shunt passive filter as a harmonic amplifying phenomina. The series active filter needs much smaller kVA rating than a conventional shunt active filter does. As a result, the combined system shows good filtering characteristics and high efficiency.This paper presents an optimum design of the shunt passive filter for a great reduction of the required kVA rating of the series active filter. It can minimize the peak voltage across the series active filter, and reduce the required kVA rating of the series active filter to 60%. The optimized system is compared in compensation characteristics with the combined system using a conventional shunt passive filter by digital computer simulation, paying attention to practical applications to large rated three-phase twelve-pulse thyristor rectifiers. Experimental results obtained by a laboratory model are shown to verify the design theory.