A Natural Current Balancing Interleaved IPOP LLC Converter With Partial Power Processing

This article proposes a natural current balancing method for the interleaved input-parallel output-parallel (IPOP) LLC converter incorporating the partial power processing (PPP) structure. In the proposed configuration, based on the principle of charge balance, the voltage gain of phases can be automatically equalized in the presence of parameter mismatch. This results in the natural balancing of phase currents without sensors or dedicated controls and is independent of the phase-shift angle. Consequently, interleaving operation with 90° phase shift can be employed to reduce output current ripples significantly. Additionally, the PPP structure allows the output voltage of the proposed converter to be regulated with high performance. A 2-kW prototype is built and tested to validate the benefits of the proposedmethod.