An LC-Resonant Differential Current Compensation Architecture for Mismatch Mitigation in Series-Connected Photovoltaic Strings

Current mismatch in series-connected photovoltaic (PV) strings restricts the string current by the weakest module, resulting in multi-peak power characteristics and reduced power utilization. To address this problem, this paper proposes a low-frequency LC-resonant differential current compensator (DCC) for current-mismatch mitigation in series-connected PV systems. The proposed DCC employs a shared LC-resonant branch composed of only a single inductor and a single capacitor as the main energy-transfer unit, avoiding the multiple distributed converters or magnetic components commonly required in conventional differential power processing architectures. Through low-frequency LC-resonant energy transfer, the DCC enables adaptive redistribution of mismatch-related differential energy, thereby relieving the series-current bottleneck and suppressing mismatch-induced multi-peak power characteristics. Theoretical analysis, simulations, and experimental validations demonstrate that the proposed method can significantly improve the maximum power utilization of PV strings with a compact circuit structure and a reduced number of energy-transfer components. Therefore, the proposed low-frequency LC-resonant DCC provides a simple, efficient, and scalable solution for mismatch mitigation and power-utilization improvement in series-connected PV systems.