Fast battery equalization with isolated bidirectional DC-DC converter for PHEV applications

Battery systems in plug-in hybrid electric vehicles (PHEV) suffer from voltage imbalance. This imbalance reduces the available capacity of certain charge/discharge cycles and shortens the battery life cycle. A new topology and smart balancing strategy for PHEV battery systems are proposed in this paper, which uses a bidirectional DC-DC converter to reduce balancing time and the number of switches needed. The simulation on a ten series connected battery cell is compared to a traditional switched capacitor equalizer.