In DC distribution system, load switching events and disturbances may cause significant overshoot in DC bus voltage under regular control strategies. To further enhance the dynamic performance of the system, a coordinated control strategy of real-time compensation utilizing EtherCAT communication is proposed in this paper. In this strategy, the state variation command is issued from the master controller to the AC-DC converter. Meanwhile, a compensation value is introduced to the DC-DC converter synchronously based on EtherCAT communication which owns the real-time and high-speed features. Theoretically, it can mitigate the transient process of DC bus voltage during master-regulated state variations. The proposed strategy is verified in a cascaded system of Dual Active Bridge (DAB) and a boost-inductorless single-phase bidirectional isolated AC-DC converter. In order to obtain the precise expression of the compensation, the small signal analysis upon both topology and control loop of the two converters is conducted. Finally, a 3.3 kW cascaded experimental platform is built to verify the correctness and effectiveness of the proposed strategy.