A Battery Charger based on Cascaded H-Bridge Rectifier with integrated PV Generators

The paper deals with a single-phase battery charger based on cascaded H-Bridge (CHB) rectifier with integrated photo-voltaic generators (PVGs). The proposed circuit topology allows to split the battery energy storage system (BESS) in smaller storage modules each of which is connected to its own dc-link of the multilevel structure. A main issue to be addressed is the inherent variability and uncertainty of PV power production which can be compensated by the grid connection to obtain the same charging rate for all the batteries, thus also keeping balanced their state-of-charge (SOC). The consequence is a power imbalance, among the power cells in the cascade, which can be handled by using a suitable control strategy along with a hybrid modulation technique. Numerical results are carried out on a 19-level CHB rectifier implemented in PLECS environment to prove the feasibility and effectiveness of the proposed design and control approach.