Multiinput PV Optimizer System With Built-in Communication Using Talkative Power Conversion

In a photovoltaic (PV) system equipped with dc power optimizers (DCPOs), communication is a critical function for ensuring reliability. This article presents a talkative power conversion (TPC) method for DCPOs using power/signal dual modulation (PSDM) to achieve integrated dc power line communication (PLC). The method integrates modulated data signal into the power control loop of a DCPO, so no transmission circuit is added for communication. The proposed PV system consists of several series-connected DCPOs and a communication hub. A communication model of the system is built, based on which the modulation/demodulation method and noise distribution are discussed. Furthermore, the cross effects between communication and power transfer are analyzed in detail, especially in pass-through mode. At last, a 2.2 kW practical system including 12 PV panels is implemented with a 3.75 kb/s data rate. The communication performance is verified in long-term running under various environments.