Energy Management Strategy of Stand-alone Photovoltaic System in Cathodic Protection Pipeline

In this paper, the stand-alone photovoltaic system for cathodic protection of underground pipelines is presented. The proposed system offers continuous and automatic adjustment of the applied voltage so that the buried pipelines receive the exact current. A modified perturb and observe (P&O) algorithm for maximum power point tracking (MPPT) is used to improve dynamic and steady state performance. The battery stores excess energy generated by PV array and supplies the load when there is a shortage of the photo voltaic (PV) power. To extend the battery lifetime and the system efficiency, the battery is connected to the DC link by a ZVS bidirectional Buck-Boost converter. A classic PI controller regulates output voltage by controlling the duty cycle of the converter. The supervisor controls the converter to operate system in suitable modes based on the state of charge (SOC) of the battery and DC link voltage. The simulation verified that the output voltage obtains the constant voltage under any climatic conditions.