Harmonic distortion performance of multi three-phase SCR-fed drive systems with controlled DC-link current under unbalanced grid

© 2017 IEEE. Grid voltage unbalance, which is considered as most common disturbance in distribution networks, may significantly affect the normal operation of the grid-connected power electronics devices including Adjustable Speed Drives (ASD), and may result in a remarkable performance degradation. In this paper, the main aim is to analyze the effects of the grid unbalanced voltage on the multi-unit three-phase ASDs with the Silicon-Controlled Rectifier (SCR)-fed front-end rectifiers, where the DC-link current is controlled utilizing an Electronic Inductor (EI) technique. In this respect, the main effective factors on the drives harmonic performance are discussed. Moreover, the analysis is performed by considering an Equally-Pulse-Space (EPS) firing approach on the SCRs. Obtained simulation and experimental results verify the proposed theoretical analysis and mathematical modelling.