Hybrid power filter for advanced power quality in industrial systems

• New hybrid power filter structure and control strategy with a split passive part.
• Very efficient HPF topology to mitigate especially higher harmonic currents.
• HPF functionality is influenced by the grid inductance changes only negligibly.
• New HPF advantages confirmed by simulations and measurements.

The paper presents the structure and control strategy of the hybrid power filter (HPF) with a split passive part. Its impedance is divided into two parts tuned to 50 Hz and 250 Hz.The HPF topology is very efficient to mitigate harmonic currents. The fundamental frequency voltage at the converter terminals is remarkably small in comparison with the grid voltage at the same moment. The HPF functionality is only negligibly influenced by the grid inductance changes.The HPF characteristics were compared with those for standard HPF topologies and the classical passive compensation by means of simulations done in the Matlab/Simulink environment. The voltage and current responses and their harmonic spectra were also measured in an industrial plant under different conditions.