DC–DC Series-resonant converter with multi-stage current-driven for balance charger of series-connected lithium-ion batteries

Abstract

Here, a novel DC–DC converter based on a series-resonant inverter and a multi-stage current-driven rectifier for the active balance charger of lithium-ion series batteries is proposed. In the proposed topology, diodes are placed in a current-driven half-wave rectifier to regulate the voltage at the terminals of the batteries. The proposed balance charger has been compared with the Cockcroft–Walton voltage multiplier, DC–DC multilevel boost converter, chain structure using an additional capacitor, and series-resonant voltage multiplier topologies. The cost of the proposed topology has not increased in comparison to other topologies and can be made modularly and more stages can be increased by adding capacitors and diodes. The experimental results are obtained from charging six lithium-ion series batteries, of which one of them has been damaged. All topologies balance and charge the rest of the batteries despite the damaged battery. The results show that the proposed topology for the converter has reduced the average balancing and charging time by 40.77% and 13.33%, respectively, compared to other topologies. Therefore, the energy losses of the proposed topology are less than the other topologies. Also, the higher energy efficiency of the proposed topology is expected due to the faster-balancing speed.