Channel Characterization and EMC Assessment of a PLC System for Spacecraft DC Differential Power Buses

This paper investigates the possibility of using the powerline communications (PLC) technology to transmit data along differential dc power buses employed in spacecraft. To this end, a point-to-point interconnection between the power control and distribution unit (PCDU) and a dc/dc converter is considered. The power bus is composed of a twisted-wire pair (TWP) above ground, and capacitive coupling and inductive decoupling networks are adopted. The analysis focuses on channel characterization and electromagnetic compatibility (EMC) assessment of a PLC link for low-speed interconnections with sensors. A transmission line model is adopted for the powerline (PL) involving measurement-based emission models for the power units connected to the line ends. Modal analysis is used to estimate the channel performance in terms of signal and noise transfer ratios. It is shown that use of a balanced transmission scheme assures higher performance both in terms of channel transfer function and immunity to the PL-conducted noise generated by dc/dc converters. A prototype of the PLC link, involving a specific implementation, is realized to prove feasibility and to analyze the system EMC behavior in terms of radiated emissions, conducted and radiated susceptibility.