Modeling and Simulation of DC Micro-grid Based on Virtual Motor Control

A flexible DC micro-grid model is proposed, which is suitable for grid-connected renewable energy and energy storage. The complete circuit topology and its corresponding control strategy are given, which can make sure energy reliability, and can automatically achieve a reasonable power distribution. In addition, based on the theory of Virtual Generator (VG), a complete control strategy of each interface is proposed, that is, the Virtual DC Generator (VDG) control strategy is adopted in the load and energy storage unit, and the Virtual Synchronous Generator (VSG) control strategy is adopted in the grid connection interface. VSG has the similar active and reactive power adjustment ability to the synchronous generator. The voltage amplitude and frequency of the grid-connected inverter are adjustable. It can simulate the inertia and damping characteristics of the synchronous generator, and overcome the impact of the traditional grid-connected inverter without inertia to the grid, which can effectively enhance the ability of the grid to accept renewable energy. What's more, the model of electric vehicles is considered into the micro-grid to meet the future trend of power grid. Simulation and experimental results verify the validity and reliability of the proposed.