An energy storage device system for a primary frequency modulation and automatic generation control (AGC) auxiliary regulation technology comprises a power generation set, a transformer, a power grid, a DC-AC converter and energy storage battery packs and is characterized in that a multi-port DC-DC converter is also arranged, so that connection ports of a plurality of energy storage battery packs are connected with respective port of the DC-DC converter, and at least one supercapacitor is also connected with the respective port of the DC-DC converter; and moreover, a load allocation system is used for receiving a dispatched AGC instruction or forming a load instruction according to a frequency of the power grid, the instruction is divided into two paths, one path passes through an energy management system to be connected with the multi-port DC-DC converter and the DC-AC converter, and the other path is connected with a distributed control system (DCS) and digital electric hydraulic (DEH) control system of the generation set to control the power generation set to work. Therefore, the peak load regulation capability of a power system can be improved, the primary frequency regulation ability and the AGC response capability of a coal-fired unit are improved, the stable running of a power plant is ensured, and energy is saved.