Multimode operation of PV-battery system with renewable intermittency smoothening and enhanced power quality

摘要

Smart grid technology has enabled the bidirectional power exchange between utility and consumers, owning renewable power sources. The major challenge to this feature is the intermittent nature of renewable sources such as photovoltaic (PV), which makes it difficult to exchange a definite amount of power with the grid. This study aims to address this challenge, by proposing a multifunctional PV-battery system to provide intermittency smoothening along with reactive power and harmonics compensation in grid-connected mode and an uninterrupted power supply mode to loads during the grid outage. The PV-battery system comprises of a boost converter, bidirectional DC-DC converter and a grid-connected voltage-source converter (VSC). The boost converter operates the PV array at the maximum power point. The bidirectional converter provides the battery charging and maintains constant DC-link voltage. The VSC uses a multimode controller, which has a current controller for grid-connected mode, voltage controller for standalone mode, a voltage and rate of change of power-based islanding detection and resynchronisation as per the IEEE 1547-2018 revised standard, for mode transitions based on grid availability. Simulated and test results validate the effectiveness of the proposed control in achieving the set objectives.