CSC-VSC Based Distributed Energy Grid Connection System and Its Control Strategy

Abstract

With the aim of carbon footprint reduction and energy internet construction, distributed renewable energies are vigorously developed, emphasizing the optimization and coordination of wind energy, solar energy, electric vehicle battery energy and so on. In order to make full use of the renewable energies and improve the flexibility of the power system, a distributed energy grid connection system based on current source converter (CSC)-voltage source converter (VSC) is proposed in this paper. The topology of the proposed system is introduced firstly. The system adopts CSC to realize partition grid and ac renewable energy connection, and a hybrid DC/DC converter which adopts CSC at the grid side and VSC at the load side to realize dc distributed renewable energy connection. A high-frequency modulation method is proposed to reduce the volume of the DC/DC converter. Then, the mathematical model of the system is analyzed. Based on the mathematical model, a comprehensive control strategy is proposed. The proposed method realizes the flexible power flow regulation in ac/dc distribution network and effective grid connection of distributed energy. Finally, the experimental model of a three-terminal CSC-VSC based distributed energy grid connection system is built on RT-LAB hardware in the loop simulation platform. The experimental results verify the correctness of the proposed system and the effectiveness of the proposed control method.