Power Distribution Management System revisited: Single-thread vs. Multithread Performance

Power Distribution Management System (PDMS) uses very sophisticated algorithms to deliver reliable and efficient functioning of power distribution networks (PDN). PDNs are represented using very large sparse matrices, whose processing is computationally very demanding. Dividing large PDNs into smaller sub-networks results in smaller sparse matrices, and further processing each sub-network in parallel significantly improves the performance of PDMS. Using multithreading to further process each sub-network however degrades PDMS performance. Single-thread processing of sub-network sparse matrices gives much better performance results, mainly due to the structure of these matrices (indefinite and very sparse) and synchronization overhead involved in multi-thread operations. In this paper an overview of PDMS system is presented, and its performance given single-thread and multiple threads is compared. The results have shown that for some applications, single-threaded implementation in multi-process parallel environment gives better performance than multithreaded implementation

An open framework for highly concurrent hardware-in-the-loop simulation

Hardware-in-the-loop (HIL) simulation is becoming a significant tool in prototyping complex, highly available systems. The HIL approach allows an engineer to build a physical system incrementally by enabling real components of the system to seamlessly interface with simulated components. It also permits testing of hardware prototypes of components that would be extremely costly to test in the deployed environment. Key issues are the ability to wrap the systems of equations (such as Partial Differential Equations) describing the deployed environment into real-time software models, provide low synchronization overhead between the hardware and software, and reduce reliance on proprietary platforms. This thesis introduces an open source HIL simulation framework that can be ported to any standard Unix-like system on any shared-memory multiprocessor computer, requires minimal operating system scheduler controls, provides a soft real-time guarantee for any constituent simulation that does likewise, enables an asynchronous user interface, and allows for an arbitrary number of secondary control components --Abstract, page iii

An Open Framework for Highly Concurrent Real-Time Hardware-in-the-Loop Simulation

Hardware-in-the-loop (HIL) real-time simulation is becoming a significant tool in prototyping complex, highly available systems. The HIL approach permits testing of hardware prototypes of components that would be extremely costly or difficult to test in the deployed environment. In power system simulation, key issues are the ability to wrap the systems of equations (such as Partial Differential Equations) describing the deployed environment into real-time software models, provide low synchronization overhead between the hardware and software, and reduce reliance on proprietary platforms. This paper introduces an open source HIL simulation framework that can be ported to any standard Unix-like system on any shared-memory multiprocessor computer, requires minimal operating system scheduler controls, enables an asynchronous user interface, and allows for an arbitrary number of secondary control components. The framework is implemented in a soft real-time HIL simulation of a power transmission network with physical Flexible AC Transmission System (FACTS) devices. Performance results are given that demonstrate a low synchronization overhead of the framework

Bit Resolution Improvement for Continuous Data Acquisition of Electrical Waveforms in Multiphase Energy Measurement Systems

A data acquisition platform has been previously developed that enables extraction of information about an electrical machine’s health and energy conversion efficiency by monitoring its electrical signals. It is desired to extend the functionality of this platform to enable multi-phase signal acquisition with higher bit resolution while providing continuous waveform sampling that does not present any gaps in information acquisition. The previously designed platform samples signals at 8 kHz and can achieve about 15 bits resolution following down sampling to 1920 Hz. To get higher bit resolution without altering the hardware, more oversampling is required. Thus, the hardware is set to sample at 64 kHz which is the maximum sampling frequency the 6-channel simultaneous sampling analog to digital converter (ADC) can provide. Sampling at higher frequencies results in larger raw data sizes while the sampling time window remains same, and this increases the data transfer time reducing the information available for analysis in a given period of time. To address this issue, in this thesis, several proposed approaches are explored and a final hybrid solution is used. The final solution achieves about 1.3 bits improvement in signal resolution compared to the original firmware, while also performing continuous waveform acquisition if the end-to-end network delay is within expected ranges

Co-simulation techniques based on virtual platforms for SoC design and verification in power electronics applications

En las últimas décadas, la inversión en el ámbito energético ha aumentado considerablemente. Actualmente, existen numerosas empresas que están desarrollando equipos como convertidores de potencia o máquinas eléctricas con sistemas de control de última generación. La tendencia actual es usar System-on-chips y Field Programmable Gate Arrays para implementar todo el sistema de control. Estos dispositivos facilitan el uso de algoritmos de control más complejos y eficientes, mejorando la eficiencia de los equipos y habilitando la integración de los sistemas renovables en la red eléctrica. Sin embargo, la complejidad de los sistemas de control también ha aumentado considerablemente y con ello la dificultad de su verificación. Los sistemas Hardware-in-the-loop (HIL) se han presentado como una solución para la verificación no destructiva de los equipos energéticos, evitando accidentes y pruebas de alto coste en bancos de ensayo. Los sistemas HIL simulan en tiempo real el comportamiento de la planta de potencia y su interfaz para realizar las pruebas con la placa de control en un entorno seguro. Esta tesis se centra en mejorar el proceso de verificación de los sistemas de control en aplicaciones de electrónica potencia. La contribución general es proporcionar una alternativa a al uso de los HIL para la verificación del hardware/software de la tarjeta de control. La alternativa se basa en la técnica de Software-in-the-loop (SIL) y trata de superar o abordar las limitaciones encontradas hasta la fecha en el SIL. Para mejorar las cualidades de SIL se ha desarrollado una herramienta software denominada COSIL que permite co-simular la implementación e integración final del sistema de control, sea software (CPU), hardware (FPGA) o una mezcla de software y hardware, al mismo tiempo que su interacción con la planta de potencia. Dicha plataforma puede trabajar en múltiples niveles de abstracción e incluye soporte para realizar co-simulación mixtas en distintos lenguajes como C o VHDL. A lo largo de la tesis se hace hincapié en mejorar una de las limitaciones de SIL, su baja velocidad de simulación. Se proponen diferentes soluciones como el uso de emuladores software, distintos niveles de abstracción del software y hardware, o relojes locales en los módulos de la FPGA. En especial se aporta un mecanismo de sincronizaron externa para el emulador software QEMU habilitando su emulación multi-core. Esta aportación habilita el uso de QEMU en plataformas virtuales de co-simulacion como COSIL. Toda la plataforma COSIL, incluido el uso de QEMU, se ha analizado bajo diferentes tipos de aplicaciones y bajo un proyecto industrial real. Su uso ha sido crítico para desarrollar y verificar el software y hardware del sistema de control de un convertidor de 400 kVA

Intrinsic electromagnetic variability in celestial objects containing rapidly spinning black holes

Analytical studies have raised the concern that a mysterious expulsion of magnetic field lines by a rapidly-spinning black hole (dubbed the black hole Meissner effect) would shut down the Blandford-Znajek process and quench the jets of active galactic nuclei and microquasars. This effect is however not seen observationally or in numerical simulations. Previous attempts at reconciling the predictions with observations have proposed several mechanisms to evade the Meissner effect. In this paper, we identify a new evasion mechanism and discuss its observational significance. Specifically, we show that the breakdown of stationarity is sufficient to remove the expulsion of the magnetic field at all multipole orders, and that the associated temporal variation is likely turbulent due to the existence of efficient mechanisms for sharing energy across different modes. Such an intrinsic (as opposed to being driven externally by, e.g., changes in the accretion rate) variability of the electromagnetic field can produce the recorded linear correlation between microvariability amplitudes and mean fluxes, help create magnetic randomness and seed sheared magnetic loops in jets, and lead to a better theoretical fit to the X-ray microvariability power spectral density.Comment: 16 pages, 9 figure

Design of a distributed data acquisition system for the ITER’s neutral beam

The International Thermonuclear Experimental Reactor (ITER) is a groundbreaking interna- tional collaboration aimed at developing fusion energy as a clean, safe, and virtually limitless source of power that brings together scientists, engineers, and experts from 35 countries to con- struct and operate the world’s largest experimental fusion reactor. Through the fusion of hy- drogen isotopes, ITER seeks to replicate the process that powers the sun and stars, harnessing the immense energy released to generate electricity. With its ambitious goals and cutting-edge technology, ITER represents a significant milestone in the pursuit of sustainable and abundant energy for the future. As part of the ITER project, the development of several systems of plasma heating is needed to achieve fusion conditions in order to reach plasma ignition. One of such heating systems is the Heating Neutral Beam (HNB), which is designed to inject a energetic beam of neutral atoms into the plasma and heat the fusion plasma by coulomb collisions of such with the plasma. This system requires of several components such as power supplies, cryopumps and cooling components working together in order to achieve a controlled and safe operation of the HNB. It also needs to work coordinated with the experimental control with high availability. The neutral beam control system is, therefore, responsible for the correct and safe operation of the two HNB units installed at ITER. The project presents an overview of the instrumentation and control system currently being developed for the Neutral Beam units and presents the development and design of a remote distributed data acquisition system prototype for the Neutral Beam instrumentation and control system. The performance of the prototype will be measured and evaluated to determine if such solution is fit for ITER requirements and can therefore be implemented into the Neutral Beam control system and other control systems within the reactor components. This project was developed under the Traineeship program by the European Joint Undertaking for ITER and the Development of Fusion Energy, Fusion For Energy (F4E). This report presents the work the author performed during such contract and under the guidance of the program’s supervisor