Development of a DC Microgrid for Enhanced Power System Efficiency and Stability

The common practice to distribute the electricity generated by a grid-tied renewable generation system results in two drawbacks: double conversion loss because of DC-AC-DC conversion and the challenge to maintain the stability and reliability of AC grid because of the intermittent generation. This paper reports a solution to both of them by using a DC microgrid. The reported DC microgrid integrates multi-renewable generations in the system. Instead of converting all the generated DC power into AC, the DC microgrid consumes the renewable energy in DC mode to reduce the double conversion loss. Meanwhile, the energy storage of the system can reduce the impact of the intermittent generation to AC grid. Furthermore, the intelligent control algorithm of the system can wisely use the stored energy to maximize the system benefit and lower the demand to the AC grid in peak hours. The modular design of the major components makes the system scalable easily. The intelligence of the control algorithm also allows the system to function as a smart endpoint in the future smart grid.