Current reference generator for 50-Hz and 16.7-Hz shunt active power filters

Abstract

This article describes a high-performance reference signal generator for shunt-type active power filters in frequency-variant environments. First, it extracts the fundamental frequency component from the distorted load current. The actual current reference is obtained by subtracting the recofundamental harmonic from the measured load current, and inverting the resulting harmonics waveform before feeding it to a current-controlled IGBT inverter section. To achieve a high-quality fundamental sinusoid estimation and real-time computational efficiency, our reference generator employs an adaptive and predictive multiplicative general parameter finite impulse response (MGP-FIR) band pass filter designed by evolutionary programming. Detailed procedures of MGP-FIR filtering and evolutionary optimisation are discussed. Presented theoretical conclusions are verified by simulation results and experiments performed on a designed laboratory prototype of the single-phase active power filter of rated power of 5.75 kVA. This is the first article reporting any kind of prototyping results with the MGP-FIR system.