In view of the technical characteristics of different energy storage technologies，a system structure and control mode of hybrid energy storage system（HESS）for AC application suitable for large-scale application is adopted.The high-pass filter is used for HESS to rationally distribute power instructions between two energy storages.To optimize the system integral adjustment ability，a strategy of supercapacitor condition adjustment is proposed based on the charging/discharging status of lithium-ion battery.The coordination control of over-charge protection，over-discharge protection and maximum power limit protection between two energy storages are discussed in detail.The results of PSCAD simulation examples show the effectiveness of the proposed method.