MULTIMODULE PARALLEL SMALL BATTERY ENERGY-STORAGE SYSTEM

This paper presents a multi-module parallel single-phase battery energ y storage system (BESS). The single module BESS to be paralleled consi sts of only a full-bridge converter. When the utility is in normal con dition, the BESS serves as a power conditioner as well as an active po wer filter. It can be arranged to charge the battery bank or to share daily peak load. In any case, the current supplied by the utility can be maintained sinusoidal and almost in phase with voltage. When the ut ility power failure happens, the BESS functions as an inverter to supp ly uninterruptible power to the load. With the good current sharing fe ature possessed by this BESS, a central power distribution control sch eme with smooth current transfer characteristic is proposed to control the parallel operation of the multi-module BESS. The current sharing of each BESS module can be programmed according to its rating and the load condition. Designs of the power circuit and the central power dis tribution control scheme are described detailedly in this paper. The e ffectiveness and performance of the proposed parallel BESS are demonst rated by some experimental results.