Design of DC Micro-grid Based on Bus Voltage Grading Control

Due to the intermittent nature of the distributed power supply in the microgrid and the indeterminate output power, real-time changes in system load can have an impact on the DC bus voltage. In order to solve these problems better, the DC microgrid bus voltage grading control strategy is designed. First, the system structure of the DC microgrid is constructed. In this paper, the bus voltage of the DC microgrid is hierarchically controlled and divided into four levels according to the bus voltage. According to the voltage level of each module and different working modes, the system is divided into five working states to ensure the DC bus voltage. Maintain system stability by reducing ripple. This paper determines the operating state of the energy storage module by detecting and comparing the load demand power and photovoltaic power generation, ie using the battery and the super capacitor as energy relaxation. The system ends to ensure the stability of the DC bus voltage. Finally, the simulation model based on MATLAB is used to verify the effectiveness of the control strategy. The simulation results show the effectiveness and correctness of the control strategy.