PERFORMANCE COMPARISON OF SHUNT ACTIVE POWER FILTER TOPOLOGIES

Abstract

The alternating current circuits in electrical power system have been a common practice. Nowadays solid state control of ac power using thyristors and other semiconductor switches is widely employed to feed controlled electrical power to electrical loads such as adjustable speed drives, furnaces, computer power supplies, HVDC systems, etc. As non linear loads these solid state converters draw harmonic and reactive power components of current from ac mains and leads to power quality problems. The problem of harmonic pollution in power distribution lines has raised a significant interest over the last years. Special attention has been dedicated to the proliferation of line current harmonics and their negative effects due to the deformation of sine waveform characteristics. The recent development of power electronic components and controlled processors allow the design of harmonic current compensating structures, so-called Active Power Filters (APF). The increasing use of power electronics based loads to improve system efficiency and controllability is increasing the concern for harmonic distortion levels in end use facilities and on the overall power system. Active power filters have been widely used for harmonic eliminatiOn. Simulation study and analysis of single phase VSI based active power filter, single phase CSI based active power filter, three phase VSI based active power filter, three phase CSI based active power filter, Multilevel Inverter based active power filter, four switching-leg topology, and capacitor mid-point topology is carried out for various conditions such as unbalanced load, unbalanced supply, step change in load, harmonics in supply and their performance is compared. Overview of FPGA and its application in active power filtering is discussed. Development of FPGA controlled single phase VSI based shunt active power filter is also discussed in detail.