The Three-Level NPC Converter Based Energy Router and Its Application in Flexible Distribution Network Control

With the high penetration rate of distributed renewable energy in the power grid, the traditional radial distribution network is difficult of tackle the multidirectional power flow. As a multi-port converter, the electric energy router (EER) enhance the flexibility of the distribution network and improves the consumption of renewable energy. In this paper, a three-port EER based on the neutral point clamped (NPC) three-level converter is proposed. An energy storage unit is integrated in the EER through the bi-directional DC/DC converter. A hierarchical coordinated control strategy is established to coordinate the power distribution between the energy storage unit and each port converter, so as to stabilize the fluctuation of renewable energy generation and realize the peak shaving and valley filling with energy storage. Matlab/Simulink is used to simulate the multi-port EER and verify its effectiveness. Through comparison under different working conditions, the simulation results prove the proposed circuit and control strategy.