A Novel Detecting Algorithm for Harmonics and Reactive Currents under Unbalanced and Non-sinusoidal Source Voltages

Harmonics and reactive currents detected in precision is the key whether active power filters work well. Methods on detecting affect compensation currents and detecting precision. A novel harmonics and reactive currents detecting algorithm in three phase circuit is proposed. It extracts positive fundamentals of source voltages and load currents using three-phase sinusoid and cosine signals with arbitrary phase, and then detects harmonics, reactive and negative currents by accurately separating positive fundamental active component from load currents. Whether waveforms of voltages are non-sinusoidal or unbalanced, the results can not be affected. Furthermore, it is without phase lock loop. Finally, it is proved to be precision and feasibility from simulation.