Performance Comparison of One Cycle and PWM Controlled Active Filters

During the last years, the increasing research in power systems and the electrical engineering development around the world, has given an incentive to new expectations in transmission and distribution. The quality of power that is supplied is also gaining more importance.

Power harmonics are called electrical pollution which will degrade the quality of the power supply. As a result, filtering process for these harmonics is needed in order to improve the quality of the power supply. Generally passive filters are used to suppress the harmonics of specific orders. Separate filters are required to suppress individual lower order harmonics. These usually consist of a bank of tuned LCfilters to suppress harmonics. The passive filters are performing better in the presence of load. In the absence of load or light loading conditions the presence of passive filters resulting in poor power quality.

The Active Power Filters (APF) is used to reduce harmonics based on load variations. The presence of active filter is resulting in reduction of the harmonics to a specific limit. It is proposed to use single active filter in place of passive filters with the objective to reduce harmonic currents. It is proposed to use one cycle controlled APF for suppressing harmonics in the presence of nonlinear loads under different loading conditions and the performance is compared with PWM controlled APF.