Communication is the key for controlling solar photo-voltaic systems. Nowadays, wireless is the technology used to control solar systems. For cost and reliability purposes, a wired communication technology is to be used. The existing power wires will be exploited to transmit data. The aim of this book is to investigate the integration of power line communications and low-voltage solar photo-voltaic systems. Binary frequency shift keying techniques and the Zero-Crossing methods are studied and implemented to achieve a transmission at low data rate over the H-bridge inverter.