Leakage Current Suppression in Double Stage SECS Enabling Harmonics Suppression Capabilities

This work deals with a harmonic control strategy for a transformerless double stage solar energy conversion system (SECS) to alleviate the leakage current in the presence of nonlinear loads enabling harmonics suppression capability. In this SECS, the PV module stray capacitance can elicit leakage current, which causes electromagnetic interferences and potential safety problems. To address these issues, the model predictive controller based adaptive harmonic compensation strategy is presented herein, which not only provides leakage current suppression but it also serves manifold ancillary power quality improvement features. The revised IEEE-519-2014 standard is incorporated in adaptive harmonic compensation strategy to achieve harmonics within recommended limits. The comparative response with a conventional control is exhibited to verify the capabilities of harmonic control strategy. Furthermore, a comparative harmonic suppression capability is analyzed herein to validate the competence of voltage controller. Various real-time simulated results are discussed to manifest capabilities of this control. The leakage current is restricted below 300 mA as per desirable safety requirements against leakage current of VDE-00126-01 and IEC-62109-2 standards. The total harmonic distortion (THD) of grid current and voltage, are achieved within permissible limits in compliance with the revised IEEE-519-2014 code.