The Adaptive Parameter Control Strategy Of Virtual Dc Machine For Energy Interface Converter

In the face of extreme climate change,actively developing renewable energy has become a necessary measure to mitigate environmental problems.Due to the intermittency and volatility of renewable energy,direct grid connection can affect the quality of electric power and the stability of power supply.Microgrids,as a critical energy exchange link between distributed power sources and distribution networks,connect renewable energy,energy storage,loads,etc.to form an independent and controllable power generation unit,which can effectively improve the reliability of power supply in distribution networks.According to different power transmission and distribution methods,microgrids are divided into AC and DC types.In terms of energy utilization efficiency and economy,DC microgrids have more advantages than AC microgrids,and have attracted widespread attention from scholars in recent years.This paper proposes a coordinated control strategy for improving the inertia characteristic of DC microgrid and prioritizing renewable energy generation.The specific content is as follows:In response to the problem that the traditional fixed-parameter virtual DC motor(VDCM)control strategy cannot adaptively adjust with the variation of DC microgrid operating conditions,a parameter adaptive VDCM control method based on logarithmic function is proposed.Firstly,by analyzing the correspondence between the two-port network and the DC motor,a mechanical rotation link of the DC motor is introduced in the P-U droop control of the DC-DC converter to obtain the influence of traditional VDCM control parameters on the transient and steady-state performance of bus voltage.Based on this,adaptive VDCM parameters are designed according to the fluctuation value and rate of change of DC bus voltage,and the transient regulation performance of DC microgrid is improved by adjusting the rotational inertia in real time.Finally,a simulation model and experimental platform are built to verify the effectiveness of the proposed platform are built to verify the effectiveness of the proposed strategy.Aiming at the problem that the traditional DC microgrid coordinated control strategy based on DC Bus Signaling(DBS)lacks inertia adjustment and poor transient characteristics,this paper embeds the adaptive VDCM control strategy into the controller of photovoltaic and energy storage interface converter,and designs a coordinated control strategy of islanded photovoltaicstorage DC microgrid with renewable energy priority generation.The control strategy can effectively balance the power distribution between each power generation unit and take into account the state of charge(SOC)of the energy storage unit,which improves the inertia of the DC microgrid while realizing the priority generation of new energy.The simulation results show that the proposed coordinated control strategy of DC microgrid can realize the smooth switching of different working modes of DC microgrid in island state,and ensure the operation stability of DC microgrid.