Mitigation of Dc-Link Voltage Oscillations To Reduce Size of Dc-Side Capacitor and Improve Lifetime of Power Converter

Abstract

Voltage and current oscillations have become a primary power quality issues for DC and AC systems. In this respect, this paper presents a new control scheme for analytical implementation of reference current generator (RCG) based power control strategies to eliminate oscillations both DC and AC sides. Benchmarking of the RCG based power control strategies are examined in terms of elimination of the power oscillations, reducing DC-link voltage oscillations, avoiding DC-side overvoltage and preventing AC-side overcurrent. Compared to the existing strategies, controlling reference active power is provided with a closed-loop control system. A noteworthy contribution of this paper is to eliminate active power oscillations, which is an effective method to suppress the DC-link voltage oscillations resulting in third-order harmonic at the grid side. This helps to reduce the size of the DC-side capacitor and also improves the lifetime of the inverter, safety and stability of the grid connected primary energy resources (PERs). Detailed comparative analysis with the most recent strategies have been performed for state of the art proposed control scheme. Finally, various case studies are presented to support the proposed control scheme can mitigate the DC-link voltage oscillations, effectively.