Input-Parallel Output-Parallel Three-Level DC/DC Converters With Interleaving Control Strategy for Minimizing and Balancing Capacitor Ripple Currents
In this paper, the input-parallel output-parallel (IPOP) three-level (TL) dc/dc converters associated with the interleaving control strategy are proposed for minimizing and balancing the capacitor ripple currents. The proposed converters consist of two four-switch half-bridge TL dc/dc converters featuring with simple and compact circuit structures, which can reduce the current stresses of the components and increase the power rating of the converter. The combination of the proposed IPOP TL circuit structure and the interleaving control strategy can greatly reduce the ripple currents on the two input capacitors not only by doubling the frequencies of these ripple currents as the universal benefit of utilizing the interleaving control strategy but also by counteracting part of these ripple currents due to the operation principle of the proposed IPOP TL circuit structure. More importantly, the ripple current imbalance between the two input capacitors can be eliminated by combining the proposed IPOP TL converters and the interleaving control strategy, which can improve the converter’s reliability in balancing the thermal stresses and lifetimes of the two input capacitors. The theoretical analysis of the ripple currents on the two input capacitors is presented in detail. Finally, the simulation and experimental results are presented to verify the proposed converters with the interleaving control strategy.