Frequency Control of Hybrid Isolated Microgrid using Droop Control

Abstract

This work contains a control method for the frequency and voltage of an isolated hybrid microgrids by controlling the active and reactive power. The frequency and voltage variations are the main issues in non-conventional energy based micro grids which are not connected with the large grid. The frequency variations should be maintained within the specified range for a reliable function of the remote micro grid. The report is focused on regulation of frequency of a solar and wind based hybrid micro grid adopting the conventional droop control mechanism. Here the batteries are responsible for providing the AC bus voltage and frequency. A control mechanism named droop control was introduced which resembles the function of synchronous generator and for those inverters connected to DERs the frequency and voltage desired set points are given. So the normal droop control method is used for generating the reference frequency for the proportional integral controllers used for controlling the value of voltage and frequency in the AC micro grid. The thorough investigation of control of the frequency is done by performing two various case studies constant load and variable generation. Between inverters, the load sharing is showcased to note sharing of power by different inverters in isolated microgrid.