A comprehensive review of improving power quality using active power filters

Power system is gradually developed into a power electronic based power system and exists various power quality problems, which promotes the development of active power filter (APF). APF has developed into a comprehensive power quality conditioner. From the perspective of circuit topology, this paper has a more comprehensive classification of existing APFs, which are divided into parallel type, series type, hybrid type and others. Then, based on the fundamental four types, each APF is reviewed from the perspectives of topology, operating principle, application scenarios, and advantages and disadvantages, which provides a reference for researchers. Finally, the problems of the current industrialized APF have been analyzed by simulation, and other existing problems also have been summarized simply, such as supra-harmonics, background harmonics, multi-function power quality Controller. Moreover, this paper also briefly summarizes the further development trend of APF.