A Review of Existing Microgrid Architectures

Abstract

The future electricity network must be flexible, accessible, reliable, and economic according to the worldwide smartgrid initiative. This is also echoed by the Sustainable Energy Authority of Ireland (SEAI) and European Electricity Grid Initiative (EEGI). In order to facilitate these objectives and to reduce green house gas (GHG) emission, research on various configurations of microgrid (μG) system is gaining importance, particularly with high penetration of renewable energy sources. Depending on the resource availability, geographical locations, load demand, and existing electrical transmission and distribution system,μG can be either connected to the grid or can work in an autonomous mode. Storage can also be a part of theμG architecture. This paper presents a critical literature review of variousμG architectures. The benefits of grid-connected or isolatedμG with storage have also been identified.

An Improved Control Strategy for a Four-Leg Grid-Forming Power Converter under Unbalanced Load Conditions

“…Since the four-leg inverter is assumed to be powered by an ideal constant DC voltage source, no controller is needed to regulate the DC-link voltage, and it is possible to consider that the DC-link voltage is constant throughout this study [5]. Table 1 presents the parameters of the four-leg VSI.…”

“…The implementation of the independent control of the single-phase system in the frame needs to create a secondary orthogonal signal from each original phase signal through a complex orthogonal signal generation (OSG) technique [5]. Several attempts have been made in the literature to generate an orthogonal signal from an original singlephase signal such as second-order generalized integrator, Kalman filter, and first-order all-pass filter (APF) methods [24][25][26][27].…”

“…In spite of the complex structure of the PI compensator, the proportional controller provides more simplicity for the stability analysis and control parameter design. Moreover, it can prevent unwanted phase delays from the reference signal [5]. However, the use of the proportional controller in the internal loop requires a high proportional gain to eliminate the steady-state error.…”

“…These serious issues have led to a considerable attempt to generate power using renewable energy sources (RES) at the low voltage level [4,5]. For applications in renewable energy and distributed generation (DG), there is a need to use power electronic inverters to convert DC power into a controlled AC power [6].…”

Community Microgrid based on micro-wind generation system

“…Micro generation systems are already being popular for last few years as distributed generators in LV networks. µGrid systems are still in the test bed [5] condition though it has several advantages over µGen system. The proposal of community based grid connected µGrid is a system where the local people of a community can develop a µGrid system by integrating their existing/newly purchased µGen systems.…”