Primary Frequency Control in Islanded Microgrids Using a Novel Smart Load

Abstract

Islanded microgrids are an inexpensive way to supply electricity to consumers in remote areas. They consist of synchronous diesel generators, distributed generators (DGs) that use renewable energy resources, energy storage systems (ESSs), and loads. The low inertia of the DGs; however, interfaces increase the complexity of frequency control in islanded microgrids and increases the possibility of system instability. In this paper, a new frequency control framework that is based on using single-stage AC-DC converters as virtual synchronous machine (VSM) smart loads to emulate the behavior of a synchronous machine (SM) is proposed to increase system inertia and reduce frequency oscillations. The AC-DC converter is based on a new topology that has been proposed by the authors. In this paper, the topology and the control system are explained and an IEEE 37 bus test feeder with the smart loads is simulated as an islanded microgrid. It is shown that using the proposed smart load results in frequency fluctuations being damped considerably faster.