Partial Power Processing Converter Design With 99% Energy Utilization Efficiency for Sodium-Ion Batteries

The wide output voltage range (e.g., 1.5–3.95 V) of sodium-ion batteries presents a challenge for converter design in terms of efficiency. This article proposes to use dual-active-bridge (DAB) based partial power processing (PPP) converter to help address voltage conversion and designed the key parameters to enhance the efficiency from perspective of a whole charging and discharging cycle. This research reveals that energy utilization efficiency of such system is a function of transformer’s turn-ratio, and boosting threshold voltage. Optimizations are made to these two factors to enhance energy utilization efficiency. This approach effectively narrows the output voltage range of sodium-ion batteries to a level comparable to that of lithium-ion batteries without inducing significant power losses. Through optimized parameter design, the proposed method achieves an energy utilization efficiency of up to 99.03%.