A battery power bank of serial battery power modules with buck-boost converters

The operation of a battery power bank with buck-boost battery power modules (BPMs) connected in series is studied. With serial configuration, the output currents of all BPMs are the same as the load current. However, the currents from batteries can be scheduled in accordance with the state-of-charges (SOCs) by adjusting the duty-ratios of the associated power converters for balanced discharging. With such a configuration, in addition to discharge equalization capability, those BPMs with completely exhausted or damaged batteries can be isolated from the battery power bank without interrupting the system operation.