An on-line adaptive filtering for selective elimination of dominant harmonics from line currents of a VSI fed drive using recursive least square algorithm

Selective harmonic elimination (SHE) low switching frequency pulse width modulation (PWM) is the viable option to voltage source inverter (VSI). This paper presents an adaptive filtering algorithm for the selective current harmonic elimination in voltage source inverter (VSI) fed drive system. The algorithm used for the proposed adaptive selective harmonic elimination (ASHE) is based on Recursive Least Squares (RLS). This method eliminates the dominant harmonics in line current and it requires only the knowledge of the frequency of the particular harmonic to be eliminated. The algorithm is simulated using MATLAB/SIMULINK tool and its performance is analyzed based on total harmonic distortion (THD), magnitude of eliminated harmonics, output voltage and current waveform. The simulation results are validated by the elimination of the fifth, seventh and eleventh harmonics and it is compared with hardware results.