Dynamic operation and control of a multi-DG unit standalone Microgrid

Different kinds of sources with different capacities can be connected to a Microgrid. In autonomous operation when Microgrid is disconnected from the main grid, beside feeding total load and sharing power between sources, voltage and frequency requirement of the loads should be met. In this paper a droop control is applied to a standalone multi-converter based power system. Frequency and voltage are drooping against active and reactive power respectively. A PI voltage and inner current controllers are designed based on dynamic equations of the system to control load voltage and output current of the converters respectively. A three phase PLL is developed for each converter. Overall system is simulated in MATLAB/Simulink software and results verify the approach of load sharing between converters in autonomous operation of the microgrid.