Evaluation of a shunt active power conditioner with a modified control scheme under nonperiodic conditions

Nonperiodic waveforms are produced in power systems under various operating conditions; it is convenient to suppress such waveforms via the active filter dedicated to harmonics. An active power conditioner is scrutinised and modified to treat both periodic and nonperiodic waveform distortions. A new consistent and practical index to assess the distortion of nonstationary and nonperiodic signals is established. Its fidelity and potential for real applications are also addressed. The conditioner operation is examined under nonperiodic load currents with different types of nonperiodicity. The proposal is compared with both Fryze´s and instantaneous power control techniques. The active conditioner is shown to be competent in compensating periodic and nonperiodic current distortions.