Integration of battery energy storage element in a CERTS microgrid

Tao

et al. 2014

IET Power Electronics

109

Voltage source inverters (VSIs) are usually used for all kinds of distributed generation interfaces in a microgrid. It is the microgrid's superiority to power the local loads continuously when the utility fails. When in islanded mode, the voltage and frequency of the microgrid are determined by the VSIs; therefore the power quality can be deteriorated under unbalanced and non-linear loads. A voltage unbalance and harmonics compensation strategy for the VSIs in islanded microgrid is proposed in this study. This method is implemented in a single synchronous reference frame (SRF) and is responsible for both the voltage unbalance and harmonic compensation. Furthermore, the virtual impedance loop is modified to improve the compensation effect. The impedance model of the VSI is built to explain the compensation ability of the proposed strategy. The whole control system mainly includes power droop controllers, a modified virtual impedance loop and inner SRF-based voltage unbalance and harmonics compensators. The proposed strategy is demonstrated in detail and validated with simulations and experiments.

Section: Virtual Impedance Loopmentioning

confidence: 99%

Voltage unbalance and harmonics compensation for islanded microgrid inverters

Tao

et al. 2014

IET Power Electronics

109

2014 49th International Universities Power Engineering Conference (UPEC)

“…In these terms, static converter interfaced BESSs are becoming an innovative resource in isolated systems, being their main characteristics perfectly suitable for micro-grids and islanded networks dynamic response requirements [1] [2].…”

Section: Control Strategy and Modelsmentioning

confidence: 99%

“…In off grid operations frequency and voltage have to be rapidly regulated, especially considering the typical low inertia of small islanded grids [1] [2]. BESSs interfaced through static converters are able to properly manage microgrids if suitable control schemes are adopted.…”

Section: Introductionmentioning

confidence: 99%

A control strategy for the management of islanded networks with renewables and storage systems

Bignucolo

Raciti

Caldon

2014

Management of intentional islanded networks is becoming more and more interesting both in developed contexts and as first electrification of rural areas, presently not reached by central transmission and distribution networks. In islanded systems or network portions operating disconnected from the main grid, aiming to maximize the exploitation of renewable sources, new control strategies to guarantee frequency and voltage stability are required. An effective compensation of load variations and the optimal management of generators' unpredictability and intermittency are core objectives. In these systems, an intelligent use of local storage units can improve the network performances, besides optimizing the renewable output. A new strategy for coordinating renewable units and a storage system is introduced and tested on a realistic simplified network. Remote communication absence does not impact on the proposed controller effectiveness. Different simulations, carried out making use of DIgSILENT PowerFactory tool, show the effectiveness of the proposed strategy.

“…Uma solução para integrar um sistema de armazenamento com bancos de baterias em uma microrrede é proposta em [8]. Essa solução considera que todas as fontes de potência da microrrede operam como fontes de tensão e seguem a estratégia convencional de controle droop [9], [10].…”

Section: Introductionunclassified

Controle da Potência Gerada em Microrredes Autônomas e Isoladas com Fontes de Energia Renováveis e Sistema de Armazenamento com Bancos de Baterias

Matos¹,

Ribeiro²,

Silva³

2014

Eletrônica de Potência

Resumo -Este trabalho apresenta uma nova estratégia para controlar a potência gerada por fontes de energia renováveis conectadas à microrredes autônomas e isoladas, que utilizam sistema de armazenamento a base de banco de baterias. O principal objetivo da estratégia de controle proposta é manter o balanço de energia dentro da microrrede para que a integridade dos bancos de baterias seja garantida, mesmo quando houver potencial para geração de mais energia do que a carga pode consumir e os bancos de baterias são capazes armazenar. Essa meta é alcançada controlando a quantidade de potência gerada dentro da microrrede, sem dissipar eventual excesso de energia gerada em cargas resistivas auxiliares e sem utilizar qualquer comunicação física entre os sistemas de controle dos conversores de potência envolvidos. A frequência elétrica da microrrede é utilizada para informar quanta potência cada fonte de energia pode gerar para que a tensão dos bancos de baterias seja mantida abaixo do seu valor máximo permitido. Um método de controle droop modificado é proposto para implementar esse tarefa. Palavras-Chave - POWER CONTROL IN AC AUTONOMOUS AND ISOLATED MICROGRIDS WITH RENEWABLE ENERGY SOURCES AND BATTERY BANKSAbstract -This paper presents a new strategy to control the power generation from existing energy sources in autonomous and isolated Microgrids with energy storage system based on battery banks. The primary subject of the proposed control strategy is to keep the energy balance into the Microgrid, in order to control the battery banks integrity even when more power can be generated than loads can consume. This goal is achieved by controlling the generated power inside the Microgrid, without using dump load or any physical communication among the power converters or individual energy source controls. The electrical frequency of the Microgrid is used to