Design of a Multiphase DC-DC Converter for Online PV Panel Characterization

This manuscript presents a method for integrating impedance spectroscopy (IS) diagnostics into photovoltaic (PV) systems using interleaved boost converters. Performing accurate IS online, however, requires a power converter that can generate clean excitation signals while minimizing its own electrical noise, which can otherwise distort the sensitive measurements. This work details a systematic design methodology for a multiphase converter where the topology, number of phases, and magnetic components are optimized specifically for high-fidelity IS diagnostics. A comparative analysis of 1- to 4-phase configurations demonstrates that a 3-phase topology offers the optimal trade-off between diagnostic signal quality and hardware complexity for typical PV operating conditions. The optimized design achieves significant ripple cancellation, with experimental results confirming a 72% reduction in output voltage ripple compared to a single-phase system. This noise suppression leads to an 18 dB improvement in the signal-tonoise ratio (SNR) for IS measurements at 10 kHz, enhancing diagnostic accuracy. This study presents a unified platform for power conversion and condition monitoring, demonstrating a hardware cost-effective approach to enabling reliable in-situ PV diagnostics.