Review of Multifunctional Inverter Topologies and Control Schemes Used in Distributed Generation Systems

Abstract

Recent developments in power electronics technology have spurred interest in the use of renewable energy sources as distributed generation (DG) generators. The key component in DG generators is a grid-connected inverter that serves as an effective interface between the renewable energy source and the utility grid. The multifunctional inverter (MFI) is special type of grid-connected inverter that has elicited much attention in recent years. MFIs not only generate power for DGs but also provide increased functionality through improved power quality and voltage and reactive power support; thus, the capability of the auxiliary service for the utility grid is improved. This paper presents a comprehensive review of the various MFI system configurations for single-phase (two-wire) and three-phase (three-or four-wire) systems and control strategies for the compensation of different power quality problems. The advances in practical applications and recent research on MFIs are presented through a review of nearly 200 papers.

A Comparative Study of Methods for Estimating Virtual Flux at the Point of Common Coupling in Grid-Connected Voltage Source Converters With LCL Filter

“…The 90° phase shifted signals needed for VF sequence separation is available from the in-quadrature and direct output signals qv' and v' from SOGI-QSGs. The transfer functions of the in-phase and in-quadrature outputs, v' and qv', with respect to the input v are given by (2) and (3) [1]. In this work, the value of k= 2 is used in all the simulations in order to ensure a compromise between the stabilization time and the overshoot [1], [14]- [16].…”

A comparative study of methods for estimating virtual flux at the point of common coupling in grid connected voltage source converters with LCL filter

“…Therefore, power converters and their control systems play an important role in the grid integration of Renewable Energy Systems (RES) like wind turbines and photovoltaic installations [1]. In most of the RES based generation systems two-level VSCs in the low voltage range are used as the power conversion stage, due to good trade-offs between costperformance and controllability [2]- [4]. However, VSC topologies are also suitable for medium voltage applications, and are becoming widely used in high voltage direct current (VSC-HVDC) applications [5]- [7].…”

Cooperative Control Strategy of Multifunctional Inverters For Power Quality Enhancement in Smart Microgrid

“…Thus, for example, if the effects linked to the reactive, unbalance and void powers at the PCC have to be compensated, the input vector iinput is put equal to the balanced active current term ia b , which can be easily calculated from (8), provided that the total active power and instantaneous voltages uPCC at the given node are known (such quantities can be measured by simple instrumentation). Hence, the error signals vector is given by -(ir…”

“…This theory has also been used for active shunt compensation to provide reactive compensation and harmonic filtering [7]. In a more global vision, those inverters are said multifunctional and different topologies and control features of them are presented in [8] and [9]. Following the works in [10], [11], the main contributions of this paper are as follows.…”