Enhancement of Power-Sharing Using Multivariable Angle Droop Control for Inverter Interfaced Distributed Generations in a Micro-Grid

A micro-grid is a distributed group of multiple renewable energy sources and loads that usually operates connected to and synchronous with the traditional grid. In addition, micro-grids possess the control capability to disconnect from the grid and operate autonomously. Frequency and voltage control of micro-grid and power-sharing between DGs are the most important goals of droop control techniques. This paper presents the multivariable angle droop control technique to enhance the power-sharing among the solar PV and Wind Power Generation under the emergency mode of operation. The developed angle droop control technique realizes real and reactive power sharing by simultaneous drooping of both phase angle and voltage amplitude. The advantage of the developed technique is that only two feedback loops are used to share the power and restore the voltage and frequency of the nominal values. The proposed control technique eliminates the Phase Locked Loop which improves the stability of the voltage source inverter in the grid. This control technique enhances the power-sharing among the DGs without a steady-state frequency drop in the micro-grid and reduces the Total Harmonic Distortion of the inverter output voltage. The performance analysis of the proposed multivariable angle droop control technique is carried out in the MATLAB-Simulink environment. In addition, the experimental results provided by the FPGA-based laboratory setup built using a 1 kW solar PV and a permanent magnet synchronous generator reaffirms the design.