Energy router is an intelligent power electronic device that can realize the active management of power flow and provide convenient access to distributed energy resource. This paper presents the structure of an AC-DC hybrid multi-port energy router, which acts as the interface between the power consumer and the distribution network. The corresponding coordinated control strategy is developed to guarantee the regular operation of the energy router and a mode switch strategy with advanced compensation is proposed to achieve seamless transition between grid-connected mode and islanded mode. A novel and practical fuzzy logic controller considering unit-time electricity charge is proposed for the energy router to prolong battery life, to improve economic benefits of power consumers, and to smooth fluctuations of renewable energy generation or load consumption. The simulation and experimental results have validated the coordinated control and energy management strategies and demonstrated that the energy router has satisfactory performance.

For the electronic power transformer, the dc voltage balance is an important issue. Unbalanced dc voltages will degrade the performance of the device and may trigger the dc voltage protection. In this paper, an overall individual dc voltage (including high-voltage and low-voltage dc-link voltages) balance strategy is proposed for the electronic power transformer with separated dc-link topology. The strategy adjusts active powers flowing through the isolation and output stages in different power modules to enhance the dc voltage balance capability. Through the strategy, the high-voltage and low-voltage dc-links can be well balanced when unbalance occurs among different power modules (e.g., component parameter mismatches or some of the high-voltage or/and low-voltage dc-links are connected with renewable energy sources or/and dc loads). The proposed strategy is analyzed and supported by experimental validation.