Jump Linear Quadratic Control for Microgrids with Commercial Loads

Due to the aging power-grid infrastructure and increased usage of renewable energies, microgrids (μGrids) have emerged as a promising paradigm. It is reasonable to expect that they will become one of the fundamental building blocks of a smart grid, since effective energy transfer and coordination of μGrids could help maintain the stability and reliability of the regional large-scale power-grid. From the control perspective, one of the key objectives of μGrids is load management using local generation and storage for optimized performance. Accomplishing this task can be challenging, however, particularly in situations where local generation is unpredictable both in quality and in availability. This paper proposes to address that problem by developing a new optimal energy management scheme, which meets the requirements of supply and demand. The method that will be described in the following models μGrids as a stochastic hybrid dynamic system. Jump linear theory is used to maximize storage and renewable energy usage, and Markov chain theory is applied to model the intermittent generation of renewable energy based on real data. Although the model itself is quite general, we will focus exclusively on solar energy, and will define the performance measure accordingly. We will demonstrate that the optimal solution in this case is a state feedback law with a piecewise constant gain. Simulation results are provided to illustrate the effectiveness of such an approach

A Parallelizable Algorithm for Stabilizing Large Sparse Linear Systems With Uncertain Interconnections

This paper proposes a new method for permuting sparse matrices into an upper block triangular from. The algorithm is highly parallelizable, which makes it suitable for large-scale systems with uncertain interconnection patterns. In such cases, the proposed decomposition can be used to develop flexible decentralized control strategies that produce a different gain matrix whenever the configuration changes. Applications to interconnected microgrids and supply and demand networks are provided to illustrate the versatility of the proposed approach

Stochastic Distributed Control for Arbitrarily Connected Microgrid Clusters

Due to the success of single microgrids, the coming years are likely to see a transformation of the current electric power system to a multiple microgrid network. Despite its obvious promise, however, this paradigm still faces many challenges, particularly when it comes to the control and coordination of energy exchanges between subsystems. In view of that, in this paper we propose an optimal stochastic control strategy in which microgrids are modeled as stochastic hybrid dynamic systems. The optimal control is based on the jump linear theory and is used as a means to maximize energy storage and the utilization of renewable energy sources in islanded microgrid clusters. Once the gain matrices are obtained, the concept of #-suboptimality is applied to determine appropriate levels of power exchange between microgrids for any given interconnection pattern. It is shown that this approach can be efficiently applied to large-scale systems and guarantees their connective stability. Simulation results for a three microgrid cluster are provided as proof of concept

Interpretations of Law and Ethics in Muslim Contexts

Law within Muslim societies is not uniform; even within Muslim majority regions it can be interpreted differently according to different denominations and legal traditions. As law forms an integral part of normative social practice, reflecting the moral and ethical principles of a society, it is important to highlight the diversity of interpretations to better enable the study of law along with the ethical principles of a community. Volume 2 of the MCA series brings together some of the many unheard voices of scholars studying law and ethics in languages other than English. It features 200 abstracts with bibliographical details in three languages (English, Arabic and Turkish), giving access to information about scholarly publications from Muslim contexts in the fields of law and sharia.https://ecommons.aku.edu/uk_ismc_series_mca/1000/thumbnail.jp

Encyclopaedias about Muslim Civilisations

Over the past 150 years, numerous encyclopaedias have been produced on Muslim civilisations, both by Muslims and non-Muslims, with different approaches to the organisation of knowledge and understanding of Muslim beliefs, cultures and societies. Access to and knowledge of these reference works and databases have until now been hindered by language barriers. The first volume in the MCA series seeks to overcome this obstacle by presenting material in three languages: English, Arabic and Turkish. This is a unique reference catalogue containing 200 annotated bibliographies and abstracts of encyclopaedias published during the nineteenth, twentieth and twenty-first centuries.https://ecommons.aku.edu/uk_ismc_series_mca/1001/thumbnail.jp

Cities as Built and Lived Environments: Scholarship from Muslim Contexts, 1875 to 2011

The rich diversity of the Muslim world is strikingly expressed through its myriad of cities. Volume 3 of the MCA series presents abstracts of scholarship examining socio-cultural and cosmopolitan processes with aspects of material culture in contemporary and historic urban contexts. The abstracts, in English, Arabic and Turkish, examine cities as built (architecture and urban infrastructure) and lived (urban social life and culture) environments. Crucial topics such as urban growth are included in abstracts about infrastructural and environmental issues, as well as migration from rural areas to cities. The topics related to cities and urban life which are discussed in these abstracts demonstrate that concerns vary among Muslim majority countries, and from one decade to another.https://ecommons.aku.edu/uk_ismc_series_mca/1002/thumbnail.jp

Un formalisme de systèmes à sauts pour la recirculation optimale des cassés dans une machine à papier

Modélisation statistique des casses de papier -- Fonctionnement d'une machine à papier -- Nature et classification des données expérimentales -- Hypothèse markovienne et validation expérimentale -- Variation des taux de transition en fonction des paramètres d'opération -- Réglage optimal de la vitesse d'opération -- Gestion optimale de la recirculation des eaux blanches et des cassés : un formalisme de systèmes à sauts Markoviens -- Gestion optimale de la recirculation des eaux blanches et des cassés : analyse des intervalles inter-incidents extensions -- Calcul approximatif des premiers temps de passage -- Loi de commande dans le cas d'un processus de casses sensible à la commande

Optimal Power and Frequency Control of Microgrid Cluster with Mixed Loads

In recent years, voltage and frequency regulation issues have been extensively discussed for the microgrid clusters (MGCs), as the high penetration of renewable energy resources (RES) might affect the continuous operation of the microgrid (MG). Furthermore, to enhance the MGC’s operation reliability, stability concerns need to be addressed. In this study, a residential MGC connected to a commercial MGC has been considered. A novel control scheme that combines both droop control and virtual inertia control is proposed. This control strategy relies on online measurements, and it can be adapted to different situations. At each iteration, the damping coefficient and droop coefficient are calculated this allows the system to switch as needed between the droop and the virtual inertia controller. This dynamic coefficient calculation allows plug and play capability, which provides the MGC with major flexibility in terms of the MGs operation and flexibility

On the margins of minority life: Zoroastrians and the state in Safavid Iran

This article looks at the treatment of the Zoroastrians by central and provincial authorities in early modern Yazd, Kirman and Isfahan, emphasizing the institutional weaknesses of the central or khāsṣạ protection they were supposed to benefit from under the Safavids (907–1135/1501– 1722). It is argued that the maltreatment the Zoroastrians endured under the Safavids had little to do with religious bigotry. Rather, it arose from rivalries between the central and the provincial services of the Safavid bureaucracy, putting Zoroastrians in Yazd, Kirman, Sistan and Isfahan at risk of over-taxation, extortion, forced labour and religious persecution. The argument developed in this article pivots on the material interest of the central and the provincial agents of the Safavid bureaucracy in the revenue and labour potentials of the Zoroastrians, and the way in which the conflict of interest between these two sectors led to such acts of persecution as over-taxation, forced labour, extortion and violenc

Jump Linear Quadratic Control for Microgrids with Commercial Loads

Due to the aging power-grid infrastructure and increased usage of renewable energies, microgrids (μGrids) have emerged as a promising paradigm. It is reasonable to expect that they will become one of the fundamental building blocks of a smart grid, since effective energy transfer and coordination of μGrids could help maintain the stability and reliability of the regional large-scale power-grid. From the control perspective, one of the key objectives of μGrids is load management using local generation and storage for optimized performance. Accomplishing this task can be challenging, however, particularly in situations where local generation is unpredictable both in quality and in availability. This paper proposes to address that problem by developing a new optimal energy management scheme, which meets the requirements of supply and demand. The method that will be described in the following models μGrids as a stochastic hybrid dynamic system. Jump linear theory is used to maximize storage and renewable energy usage, and Markov chain theory is applied to model the intermittent generation of renewable energy based on real data. Although the model itself is quite general, we will focus exclusively on solar energy, and will define the performance measure accordingly. We will demonstrate that the optimal solution in this case is a state feedback law with a piecewise constant gain. Simulation results are provided to illustrate the effectiveness of such an approach