OPERATION CONTROL OF PARALLELED 3-PHASE BATTERY ENERGY-STORAGE SYSTEM

Parallel operation for capacity enlargement of three-phase battery ene rgy storage system (3 phi BESS) is presented. The proposed paralleled system consists of some inner-loop parallel-connected current-regulate d pulse width modulated (CRPWM) converters, a current command distribu tor and an outer-loop common controller. Every single-module CRPWM 3 p hi converter possesses good current tracking control characteristics, so is easy to parallel connect. The proposed current command distribut or receives current commands from the common controller and generates suitable current commands for each paralleled converter module accordi ng to the proposed current sharing control strategy. The sophisticated system arrangement of the common controller gives the BESS many power processing functions, When it is connected to the utility grid, it ca n be arranged to give peak load shaving, active power filtering, power factor correction and battery charging, In the event of utility failu re the BESS can supply uninterrupted power with low distortion sinusoi dal voltage waveform to critical loads. Performance of the proposed pa ralleled BESS at various operating conditions is demonstrated experime ntally.