Universal dual-port grid-forming control: bridging the gap between grid-forming and grid-following control

We study a dual-port grid-forming (GFM) control for power systems containing ac and dc transmission, converter-interfaced generation and energy storage, and legacy generation. To operate such a system and provide standard services, state-of-the-art control architectures i) require assigning grid-following (GFL) and GFM controls to different converters, and ii) result in highly complex system dynamics. In contrast, dual-port GFM control (i) subsumes standard functions of GFM and GFL controls in a simple controller, ii) can be applied to a wide range of emerging technologies independently of the network configuration, and iii) significantly reduces system complexity. In this work, we provide i) an end-to-end modeling framework that allows to model complex topologies through composition of reduced-order device models, ii) an in-depth discussion of universal dual-port GFM control for emerging power systems, and iii) end-to-end stability conditions that cover a wide range of network topologies, emerging technologies, and legacy technologies. Finally, we validate our findings in a detailed case study

Uvođenje tehnika zasnovanih na modelu u razvoj aplikacija za ugradbene sustave s vremenskim ograničenjima

This paper investigates the feasibility of integrating legacy software processes and tools into the paradigm of model-based development of industrial real-time embedded systems. Research has been conducted on the example of using legacy assembly code for automatic code generation scheme inside MATLAB/Simulink environment. A sample Simulink model has been presented, code has been generated from it and its correctness has been validated by back-to-back comparison with the simulation results.Ovaj rad ispituje mogućnost integriranja naslije.enih procesa i alata za razvoj programske podrške namijenjene industrijskim ugradbenim računalnim sustavima s nametnutim vremenskim ograničenjima u paradigmu razvoja zasnovanog na modelu. Istraživanje je provedeno na primjeru korištenja naslijeđenog asemblerskog programskog koda pri automatskoj generaciji izvršnog koda unutar MATLAB/Simulink okruženja. Prikazan je primjer Simulink modela iz kojega je generiran kod čija je ispravnost utvrđena usporedbom s rezultatima simulacije

Insights into the Thermal Generation Futures of Isolated Island Electricity Systems Using System Dynamics

In future, long-term thermal generation investments will be greatly influenced by the best available mixes of legacy fossil fuels and renewable sources. Intuitively, a detailed first look at the dynamics which surrounds thermal investments will assist policy makers in shaping optimally required generation mixes. To achieve this, a system dynamics model of an isolated island electricity system was developed. This model gauges the long-term investment decisions that can exist within such systems. It addresses the thermal capacity additions and the extent to which financially influenced and demand growth influenced additions affects the long-term stability of the system. Reflecting a reality typical of island systems, this model does not have a supply and demand driven pricing mechanism and thus adopts exogenous electricity tariffs. It however accounts endogenously for changes in the thermal capacity margins and capacity costing. The case study used considers the Azorean island of Sao Miguel; which provides a background for the model and is used for testing its ability to capture various aspects of historical behaviors and real-world influences on the long-term thermal generation decisions. The paper concludes with a discussion of the investment decision insights gained and the possible future extensions, uses and modifications of the model

Pattern-Based Systems Engineering (PBSE) - Product lifecycle Management (PLM) integration and validation

Mass customization, small lot sizes, reduced cost, high variability of product types and changing product portfolio are characteristics of modern manufacturing systems during life cycle. A direct consequence of these characteristics is a more complex system and supply chain. Product lifecycle management (PLM) and model based system engineering (MBSE) are tools which have been proposed and implemented to address different aspects of this complexity and resulting challenges. Our previous work has successfully implemented a MBSE model into a PLM platform. More specifically, Pattern based system engineering (S* pattern) models of systems are integrated with TEAMCENTER to link and interface system level with component level, and streamline the lifecycle across disciplines. The benefit of the implementation is two folded. On one side it helps system engineers using system engineering models enable a shift from learning how to model to implementing the model, which leads to more effective systems definition, design, integration and testing. On the other side the PLM platform provides a reliable database to store legacy data for future use also track changes during the entire process, including one of the most important tools that a systems engineer needs which is an automatic report generation tool. In the current work, we have configured a PLM platform (TEAMCENTER) to support automatic generation of reports and requirements tables using a generic Oil Filter system lifecycle. There are three tables that have been configured for automatic generation which are Feature definitions table, Detail Requirements table and Stakeholder Feature Attributes table. These tables where specifically chosen as they describe all the requirements of the system and cover all physical behaviours the oil filter system shall exhibit during its physical interactions with external systems. The requirement tables represent core content for a typical systems engineering report. With the help of the automatic report generation tool, it is possible to prepare the entire report within one single system, the PLM system, to ensure a single reliable data source for an organization. Automatic generation of these contents can save the systems engineers time, avoid duplicated work and human errors in report preparation, train future generation of workforce in the lifecycle all the while encouraging standardized documents in an organization

Leveraging legacy codes to distributed problem solving environments: A web service approach

This paper describes techniques used to leverage high performance legacy codes as CORBA components to a distributed problem solving environment. It first briefly introduces the software architecture adopted by the environment. Then it presents a CORBA oriented wrapper generator (COWG) which can be used to automatically wrap high performance legacy codes as CORBA components. Two legacy codes have been wrapped with COWG. One is an MPI-based molecular dynamic simulation (MDS) code, the other is a finite element based computational fluid dynamics (CFD) code for simulating incompressible Navier-Stokes flows. Performance comparisons between runs of the MDS CORBA component and the original MDS legacy code on a cluster of workstations and on a parallel computer are also presented. Wrapped as CORBA components, these legacy codes can be reused in a distributed computing environment. The first case shows that high performance can be maintained with the wrapped MDS component. The second case shows that a Web user can submit a task to the wrapped CFD component through a Web page without knowing the exact implementation of the component. In this way, a user’s desktop computing environment can be extended to a high performance computing environment using a cluster of workstations or a parallel computer

Transitioning Applications to Semantic Web Services: An Automated Formal Approach

Semantic Web Services have been recognized as a promising technology that exhibits huge commercial potential, and attract significant attention from both industry and the research community. Despite expectations being high, the industrial take-up of Semantic Web Service technologies has been slower than expected. One of the main reasons is that many systems have been developed without considering the potential of the web in integrating services and sharing resources. Without a systematic methodology and proper tool support, the migration from legacy systems to Semantic Web Service-based systems can be a very tedious and expensive process, which carries a definite risk of failure. There is an urgent need to provide strategies which allow the migration of legacy systems to Semantic Web Services platforms, and also tools to support such a strategy. In this paper we propose a methodology for transitioning these applications to Semantic Web Services by taking the advantage of rigorous mathematical methods. Our methodology allows users to migrate their applications to Semantic Web Services platform automatically or semi-automatically

Towards an Intelligent Workflow Designer based on the Reuse of Workflow Patterns

In order to perform process-aware information systems we need sophisticated methods and concepts for designing and modeling processes. Recently, research on workflow patterns has emerged in order to increase the reuse of recurring workflow structures. However, current workflow modeling tools do not provide functionalities that enable users to define, query, and reuse workflow patterns properly. In this paper we gather a suite for both process modeling and normalization based on workflow patterns reuse. This suite must be used in the extension of some workflow design tool. The suite comprises components for the design of processes from both legacy systems and process modeling