Improvement in power quality using hybrid power filters based on robust extended Kalman filter

This paper presents a Hybrid Active Filter (HAF) used in the distribution network and is required for compensating reactive power in the load end and mitigate harmonics for the improvement of power quality. The compensation process used in this paper reduces number of sensors and also reduces the complication and depends on source current extraction. Initially for extraction of reference currents from harmonics surrounded line current, the Proportional-Integral (PI) or Fuzzy Logic Controller (FLC) is used, which controls the dc-link voltage of the inverter. The HAPF is designed with the use of Voltage Source Inverter (VSI). In this paper, an innovative approach called robust extended Kalman filter (RECKF) is implemented for reference current estimation/calculation using model predictive current (MPC). This RECKF-MPC essentially requires less number of voltage sensors and also overcome the problems associated with PI controllers like gain tuning. The new RECKF with MPC is compared with conventional PI and FLC and observed to be providing better performance to improve the power quality.