Balanced discharging for serial battery power modules with boost converters

A group of boost-type battery power modules (BPMs) are connected in series to cope with a higher output voltage. The operations of BPMs in series are mutually interactive. However, all batteries in the BPMs can substantially be discharged individually so that they can realize the balanced discharging control strategy, by which the battery currents are scheduled in accordance with their state-of-charges (SOCs). A battery power source formed by 10 boost-type BPMs is built and tested. Each BPM employs an associated micro controller for detecting the load voltage, estimating the SOCs, and controlling the duty ratios of the power converters. Experimental results demonstrate the balanced discharging capability of the serial BPMs.