Improved DC-Link Voltage Control Scheme for Standalone PV Renewable Energy System

In this paper, an improved DC-Link voltage control algorithm is proposed for the application on a standalone photovoltaic (PV) renewable energy system. The algorithm is based on the perturb & observed based voltage regulator (POVR) algorithm. By deploying the proposed algorithm with a buck-boost converter together with the inclusion of dynamic step size, ∆D changing technique, the suggested algorithm managed to have a very good balance between tracking speed and output voltage ripple. This is proven through the conducted simulation where in overall, the proposed algorithm produced the highest and lowest output voltage ripple of 0.1% and 0.3%, respectively. In terms of tracking time, the highest and lowest recorded times are 0.05 s and 0.9 s, respectively. The tracking times are only marginally higher than the POVR with large ∆D and much lower than the POVR with small ∆D. On the other hand, the output voltage ripples using the proposed algorithm are found to be considerably lower than the POVR with large ∆D and only slightly larger than the POVR with small ∆D.