Energy balance scheme for modularization of battery and DC/DC converter in parallel

Individual difference of parallel batteries can cause battery overcharging or over-discharging. More seriously, single battery failure can result in system fault. An energy balancing strategy for battery stage of charge (SOC) balance and DC-DC converter output current sharing is proposed. In addition, the system is designed to cut off the module immediately once any cell fails. This strategy can extend batteries life effectively and enhance the system redundancy. Furthermore, two controllers are designed, one controller regulates the duty ratio of DC-DC converter to make the batteries SOC balanced when the SOC of cell is different, another controller is responsible for output current sharing after SOC balance. The simulation and experiment verification results show the effectiveness of the strategy.