A Review of Voltage and Frequency Control for Inverter-Based Islanded Microgrids

Abstract

Distributed generation sources are usually located near the loads, and with proper management, they prove to be reliable and beneficial to consumers. They can be operated in a grid connection or autonomously. Control of parameters such as frequency and voltage for the efficient and effective operation of the islanded and grid-connected microgrids is very essential for power system stability. In a synchronous machine, the change in speed or frequency variation is controlled by the inertial response of the rotor resulting in stable power quality. However, inverter-based microgrids lack rotating masses which results in control challenges. When there is an imbalance between nonlinear loads and the generated power, variations of system voltage occur which results in instabilities. This happens in systems with an increased number of power electronic converter-based systems where proper control techniques must be employed. This paper provides a cutting-edge review in the area of voltage and frequency control techniques of inverter-based microgrids operating in islanded mode. This paper has also looked at the power-sharing strategy by connecting two distributed generators in parallel to mimic the droop control method employed in the synchronous machine to enhance the inertial response of the inverter-based microgrids.