One essential problem of battery energy application is the coordinated control of distributed battery energy storage systems(BESS). To study the aggregation of different BESS participating in automatic generation control

a feedback control method of the state of charge(SOC)is firstly proposed. Secondly

a cost model for the charge and discharge loss and battery aging is established. Thirdly

by defining each control cycle's marginal loss cost and marginal aging cost

a market-based control method without iteration is proposed to achieve the real-time optimal power allocation within BESS aggregator. Finally

a simulation analysis on the effectiveness of several SOC control methods and coordinated control methods of BESS is implemented. The results verify the effectiveness of the proposed method.