Research On Coordinated Control Of Distributed Dc Microgrid With Two Dc Buses

With the change of the natural energy structure and the vigorous development of distributed energy power supply technology,the penetration rate of distributed energy in the power grid has grown rapidly,which has caused significant changes in the composition and form of traditional distribution networks and microgrids.To put forward higher requirements for the coordinated control of the power grid,coordinate the operating characteristics of the microgrid and reasonably distribute the distributed micro-sources,reasonably distribute the power of the wind and photovoltaic power generation units,a coordinated control of the wind and solar DC microgrid is designed.For the wind power unit in the system,analyze its power generation principle and mathematical model,and build a wind power model with direct-drive synchronous generator in MATLAB/Simulink.Aiming at the wind power unit,an improved control system based on disturbance observation method is designed.Through simulation,under the rapid change of wind speed,the wind power system can quickly track the optimal leaf speed ratio,so as to track the maximum power.Aiming at the photovoltaic power generation unit in the system,its working principle and mathematical model are analyzed.Based on the disturbance observation method and photovoltaic power generation model,a photovoltaic power generation control system based on the model predictive control method is designed.Through simulation analysis,compared with the perturbation observation method,the tracking accuracy and response time are improved by 3.11% and 5.5%,respectively,under the condition that the light changes.A mathematical model of a hybrid energy storage system composed of supercapacitors and batteries is established,and its working principle is analyzed.An energy storage control system based on the droop control method is designed.Through simulation,when the system load changes suddenly,the system can absorb or supplement low-frequency and high-frequency power,effectively suppress the disturbance of the load bus to the system bus voltage,stabilize the system bus voltage at the rated range,ensure power supply and Unit's operational reliability.Aiming at the problems of independence and non-linearity in the power generation process of the wind and photovoltaic power generation units in the system,a double-layer bus distributed DC microgrid coordinated control system with wind and sunlight was designed.Based on the unit model of the system,combined with distributed predictive control algorithms,the principles of wind power priority and photovoltaic power generation are realized,and the two-way power flow between microgrids is realized under the coordinated control of bi-directional converters between micro-grids.This control method can realize the rational distribution principle of the power of each generating unit in the system when the load changes.Figure 44;Table 2;Reference 59...