Improved Ramp-Rate and Self Consumption Ratio In A Renewable-Energy-Based DC Micro-Grid

Abstract

Power fluctuations, especially in LV grids, are increasing due to the continuing penetration of renewable energy sources which are naturally variable and characterized by fast transients of the energy production. In order to improve the power quality aspects, the authors show a test bench emulating a DC micro-grid comprising a PV system, various loads and an energy storage system. This micro-grid is interfaced to the AC public distribution grid through a single bidirectional converter. The design of the whole system has the following goals: i) supply the connected DC loads with a stabilized voltage; ii) guarantee the PV source operation in MPP in all irradiation conditions and dynamics, iii) limit the ramp -rate of the power exchanged with the AC grid and iv) improve the on. -site consumption of the locally produced energy. The feasibility of the solution is demonstrated by using off -the -shelves components for the hardware and developing an ad hoc software for the controller. The effectiveness of the solution is shown by experimental measurements of the power flows through the system in different conditions of generation and consumption.