Sliding-Mode Perturbation Observer-Based Sliding-Mode Control for VSC-HVDC Systems

This chapter develops a sliding-mode perturbation observer-based sliding-mode control (POSMC) scheme for voltage source converter-based high voltage direct current (VSC-HVDC) systems. The combinatorial effect of nonlinearities, parameter uncertainties, unmodeled dynamics, and time-varying external disturbances is aggregated into a perturbation, which is estimated online by a sliding-mode state and perturbation observer (SMSPO). POSMC does not require an accurate VSC-HVDC system model and only the reactive power and DC voltage at the rectifier side while reactive and active powers at the inverter side need to be measured. Additionally, a considerable robustness can be provided through the real-time compensation of the perturbation, in which the upper bound of perturbation is replaced by the real-time estimation of the perturbation, such that the over-conservativeness of conventional sliding-mode control (SMC) can be effectively reduced. Four case studies are carried out on the VSC-HVDC system, such as active and reactive power tracking, AC bus fault, system parameter uncertainties, and weak AC gird connection. Simulation results verify its advantages over vector control and feedback linearization sliding-mode control. Then, a dSPACE-based hardware-in-the-loop (HIL) test is undertaken to validate the implementation feasibility of the proposed approach

Hardware In The Loop Simulation Of Underactuated Mechanical Systems

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2007Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2007Hava ve Uzay araçları gibi kritik sistemler için kontrolör tasarımında asıl sisteme benzer ve gerçek-zamanlı (Real-Time) çalışabilen benzetim sistemleri; ileride çıkabilecek birçok arızanın, henüz tasarım ve test aşamasında çözülmesini sağlamaktadır. Bu çalışmada, gerçek-zamanlı benzetim yapabilen ve klasik benzetim yöntemlerine göre asıl sistem davranışına daha yakın sonuçlar veren Donanım Çevrimli Benzetim (Hardware-in-the-loop Simulation) yöntemi kullanılarak, Eksik Uyarımlı (Underactuated) mekanik sistemlerin benzetimi üzerine çalışılmıştır. Gerçeklenen sistem üzerinde ilk olarak, 1-Serbestlik derecesine sahip olan basit sarkaç modelinin benzetimi yapılmıştır. Platform üzerinde en fazla 2-Serbestlik derecesine sahip mekanik sistemler test edilebilmektedir. Donanım Çevrimli Benzetim yöntemine dayalı bu platform sayesinde farklı mekanik sistemlerin, model üzerinde yapılacak değişiklikler ve bazı sistem parametrelerinin ayarlanmasıyla, gerçek-zamanlı benzetimi yapılabilir.In controller design for the critical systems like aircrafts and space vehicles, real-time simulation systems provides to designers to seize the failures that will be possible for the designed system, during the test and design process. In this study, underactuated mechanical systems simulation is processed using Hardware-in-the-loop Simulation technique for its real-time simulation and more precise results superiorities with respect to conventional simulation techniques. A simple pendulum model is simulated in the implemented system as a 1-degree-of-freedom system. Mechanical systems, which have 2-degrees-of-freedom, could be tested on the platform. Different kinds of mechanical systems could be simulated on this platform by means of Hardware-in-the-Loop simulation technique, only requires some parameter tuning process.Yüksek LisansM.Sc

Desenvolvimento de bancada virtual para simulação e monitorização de dispositivos de aquecimento de água

A controller for thermal systems is normally equipped with many facilities to make it flexible and the heating systems more cost-efficient. This results in a number of input parameters to be given by the user. It is not obvious how to choose appropriate values for these parameters unless the user has a large experience in this field. Water heating is a very important part of a household's energy use, and tankless gas water heaters (TGWH) are widely used. There are design and engineering challenges to develop more efficient devices, with lower emissions of pollutant gases and providing comfort improvements from the user point of view. Mathematical and semi-empirical models of the thermal systems were developed in order to simulate the dynamic models of water heating devices. A simulated environment is a less expensive and fastest way of evaluating the relative merits of different control schemes for a given thermal system. A technique to accelerate the process for developing controllers was implemented. Hardware-in-the-loop simulation (HILS) has proved to be very useful to test hardware controllers in virtual environments simulated in real-time. In the scope of the Smart Green Homes Project, a virtual test bench with a TGWH was proposed to support the multiple phases of controller's development, whether it is to control a real or a virtual system. The experimental platform was developed to test the implemented hybrid models performance in hardware-in-the-loop simulation experiences. The platform is composed by a TGWH with a group of sensors, by real-time hardware and by a package of software tools for data acquisition and control. In the final stage of this work, two case studies were carried out, in which the first was dedicated to the validation of the virtual bench concept and the second was to control and monitor a water heating device. Very satisfactory results, from a set of HILS experiences performed in real-time simulations, were obtained for the semi-empirical models proposed.Um controlador para sistemas térmicos está normalmente equipado com muitas instalações para o tornar flexível e os sistemas de aquecimento mais económicos. Isto resulta numa série de parâmetros de entrada a serem dados pelo utilizador. Não é óbvio como escolher valores apropriados para estes parâmetros, a menos que o utilizador tenha uma grande experiência neste campo. O aquecimento de água é uma parte muito importante do consumo de energia de um agregado familiar, e os aquecedores de água a gás sem tanque (TGWH) são amplamente utilizados. Há desafios de projeto e engenharia para desenvolver dispositivos mais eficientes, com menores emissões de gases poluentes e proporcionando melhorias de conforto do ponto de vista do utilizador. Foram desenvolvidos modelos matemáticos e semi-empíricos dos sistemas térmicos para simular os modelos dinâmicos dos dispositivos de aquecimento de água. Um ambiente simulado é uma forma menos dispendiosa e mais rápida de avaliar os méritos relativos de diferentes esquemas de controle para um determinado sistema térmico. Foi implementada uma técnica para acelerar o processo de desenvolvimento de controladores. A simulação Hardware-in-the-loop (HILS) provou ser muito útil para testar controladores de hardware em ambientes virtuais simulados em tempo real. No âmbito do projecto Smart Green Homes, foi proposta uma bancada de ensaios virtual com um TGWH para apoiar as múltiplas fases de desenvolvimento do controlador, seja para controlar um sistema real ou virtual. A plataforma experimental foi desenvolvida para testar o desempenho dos modelos híbridos implementados em experiências de simulação hardware-in-the-loop. A plataforma é composta por um TGWH com um grupo de sensores, por hardware em tempo real e por um pacote de ferramentas de software para aquisição e controlo de dados. Na fase final deste trabalho, foram realizados dois estudos de caso, em que o primeiro foi dedicado à validação do conceito da bancada virtual e o segundo foi para controlar e monitorizar um dispositivo de aquecimento de água. Foram obtidos resultados muito satisfatórios, a partir de um conjunto de experiências HILS realizadas em simulações em tempo real, para os modelos semi-empíricos propostos.Mestrado em Engenharia Mecânic

An architecture for embedded system communication

Time is a major constraint in the development of most embedded systems. In many cases, the development of embedded software is directly dependent on the development of the embedded systems. This calls for a development framework that enables embedded software and hardware to be developed in parallel. In an attempt to solve the problem, a concept prototype hardware-in-the-loop (HIL) simulation methodology has been proposed and implemented at the Ohio State University for the TMS320LF2407A DSP board. We build on top of that HIL system by rewriting the low level device drivers that allow data and control information to be set simultaneously, thus, creating a software abstraction layer over various devices available on the DSP board. The device drivers allow data access at the processor and the pin level for the devices on the DSP board. This abstraction simulates external devices in a transparent manner using a device driver library that provides the same programming interface to the device simulators as to real devices. Also, it allows for the testing of both real and simulated hardware connected to the DSP board as a part of the embedded system. The main advantages of the framework are rapid prototyping, unit testing and monitoring. We also modify the existing serial line protocol and perform a comparison between the new and the existing protocol and show that the new protocol is efficient for large data transport. This protocol allows for the effective utilization of serial line bandwidth when the DSP board is used for signal processing or voice based applications. We present the virtual testbed as a software development tool. We conclude by exploring the future directions for the applications

A fast remotely operable digital twin of a generic electric powertrain for geographically distributed hardware-in-the-loop simulation testbed

The automotive industry today is seeing far-reaching and portentous changes that will change the face of it in the foreseeable future. Digitalisation and Electrification are two of the key megatrends that is changing the way vehicles are developed and produced. A recent development in R&D process is the Hardware-in-the-Loop (HIL) method that uses a hybrid approach of testing a physical prototype immersed in a virtual environment, which is nowadays being creatively re-applied towards geographically separated multi-centre testing strategies, that suits the horizontally integrated and supply-chain driven industry very well. Geographical separation entails the deployment of a “Digital Twin” in remote centre(s) participating in multi-centre testing. This PhD aims to produce a highly robust, efficient, and rapidly computable Digital Twin of a generic electric powertrain using the multi-frequency averaging (MFA) technique that has been extended for variable frequency operation. This PhD also aims to commission a local HIL simulation testbed for a generic electric power inverter testing. The greater goal is to co-simulate the local HIL centre testing a prototype inverter, and its Digital Twin in a different location “twinning” the prototype inverter as best as possible. A novel approach for the Digital Twin has been proposed that employs Dynamic Phasors to solve the system in the frequency domain. An original method of multiplication of two signals in the frequency domain has been proposed. The resultant model has been verified against an equivalent time domain switching model and shown to outperform appreciably. A distinctive advantage the MFA Digital Twin offers is the “fidelity customisability”; based on application, the Twin can be set to compute a low (or high)-fi model at different computational cost. Finally, a novel method of communicating high-speed motor shaft position information using a low-speed processing system has been developed and validated. This has been applied to run real-life HIL simulation cycles on a test inverter and effects studied. The two ends of a multi-HIL testbed, i.e., local HIL environment for an inverter, and its Digital Twin, has been developed and validated. The last piece of the puzzle, i.e., employing a State Convergence algorithm to ensure the Digital Twin is accurate duplicating the performance of its “master”, is required to close the loop. Several ideas and process plans have been proposed to do the same

A Review of Wind Tunnel Based Virtual Flight Testing Techniques for Evaluation of Flight Control Systems

Wind tunnel based Virtual Flight Testing (VFT) is a dynamic wind tunnel test for evaluating flight control systems (FCS) proposed in recent decades. It integrates aerodynamics, flight dynamics, and FCS as a whole and is a more realistic and reliable method for FCS evaluation than traditional ground evaluation methods, such as Hardware-in-the-Loop Simulation (HILS). With FCS evaluated by VFT before flight test, the risk of flight test will be further reduced. In this paper, the background, progress, and prospects of VFT are systematically summarized. Specifically, the differences among VFT, traditional dynamic wind tunnel methods, and traditional FCS evaluation methods are introduced in order to address the advantages of evaluating FCS with VFT. Secondly, the progress of VFT is reviewed in detail. Then, the test system and key technologies of VFT for FCS evaluation are analyzed. Lastly, the prospects of VFT for evaluating FCS are described

Hardware-in-the-loop simulations and control designs for a vertical axis wind turbine

Control designs play an important role in wind energy conversion systems to achieve high e ciency and performance. In this study, hardware-in-the-loop simulations (HILS) are carried out to design control algorithms for small vertical axis wind turbines (VAWT). In the HILS, the wind torque is calculated from the power coe cient of an experimental VAWT and applied to a motor that drives the generator in the VAWT simulator, which mimics the dynamics of the real VAWT rotor. To deal with the disturbance torques in the VAWT simulator, a virtual plant was introduced to obtain an error between the speeds in HIL system and the plant. This error is used to generate a disturbance torque compensation signal by a proportional-integral (PI) controller. The VAWT simulator successfully mimics the dynamics of the VAWT under various wind speed conditions and provides a realistic framework for control designs. A maximum-power-point-tracking (MPPT) and a proposed simple non-linear control are presented for the control of the VAWT. The control algorithms were tested in the HILS under step up-down, sinusoidal and realistic wind conditions. The output power results are compared with each other and the numerically estimated optimum values. The effects of the permanent-magnet synchronous generator (PMSG) parameters on the system e ciency were investigated, and a performance comparison in numerical simulation was made between the present PMSG and two other generators available in the market

Definition and verification of a set of reusable reference architectures for hybrid vehicle development

Current concerns regarding climate change and energy security have resulted in an increasing demand for low carbon vehicles, including: more efficient internal combustion engine vehicles, alternative fuel vehicles, electric vehicles and hybrid vehicles. Unlike traditional internal combustion engine vehicles and electric vehicles, hybrid vehicles contain a minimum of two energy storage systems. These are required to deliver power through a complex powertrain which must combine these power flows electrically or mechanically (or both), before torque can be delivered to the wheel. Three distinct types of hybrid vehicles exist, series hybrids, parallel hybrids and compound hybrids. Each type of hybrid presents a unique engineering challenge. Also, within each hybrid type there exists a wide range of configurations of components, in size and type. The emergence of this new family of hybrid vehicles has necessitated a new component to vehicle development, the Vehicle Supervisory Controller (VSC). The VSC must determine and deliver driver torque demand, dividing the delivery of that demand from the multiple energy storage systems as a function of efficiencies and capacities. This control component is not commonly a standalone entity in traditional internal combustion vehicles and therefore presents an opportunity to apply a systems engineering approach to hybrid vehicle systems and VSC control system development. A key non-­‐functional requirement in systems engineering is reusability. A common method for maximising system reusability is a Reference Architecture (RA). This is an abstraction of the minimum set of shared system features (structure, functions, interactions and behaviour) that can be applied to a number of similar but distinct system deployments. It is argued that the employment of RAs in hybrid vehicle development would reduce VSC development time and cost. This Thesis expands this research to determine if one RA is extendable to all hybrid vehicle types and combines the scientific method with the scenario testing method to verify the reusability of RAs by demonstration. A set of hypotheses are posed: Can one RA represent all hybrid types? If not, can a minimum number of RAs be defined which represents all hybrid types? These hypotheses are tested by a set of scenarios. The RA is used as a template for a vehicle deployment (a scenario), which is then tested numerically, thereby verifying that the RA is valid for this type of vehicle. This Thesis determines that two RAs are required to represent the three hybrid vehicle types. One RA is needed for series hybrids, and the second RA covers parallel and compound hybrids. This is done at a level of abstraction which is high enough to avoid system specific features but low enough to incorporate detailed control functionality. One series hybrid is deployed using the series RA into simulation, hardware and onto a vehicle for testing. This verifies that the series RA is valid for this type of vehicle. The parallel RA is used to develop two sub-­‐types of parallel hybrids and one compound hybrid. This research has been conducted with industrial partners who value, and are employing, the findings of this research in their hybrid vehicle development programs

Modular multilevel converter with embedded batteries as a motor controller.

This thesis details the design of the control system and hardware for a prototype of the new inverter topology the modular multilevel converter with embedded batteries for electric vehicle applications. Within this topology, the battery cells incorporated within the battery pack are directly integrated into the motor controller/ power converter by replacing the individual module capacitors with batteries. Since the batteries are directly connected to the module switching circuit, the batteries can be individually balanced using the same technique as an active battery management system, without the need for external energy-shunting hardware. A control algorithm for balancing the embedded batteries without affecting the motor control scheme with significantly unbalanced battery cells is presented and discussed. A multilevel space vector modulation scheme using the abc-reference frame for the selection of space vectors is developed. Initial testing of both the simulation model and prototype was carried out using a static RL load to test the PWM scheme and battery SOC balancing scheme. A Field-oriented control scheme was then designed and implemented for controlling a salient pole surface-mounted PMSM. The performance of the converter as a motor controller was assessed in terms of ability to balance the SOC of the embedded module batteries and total harmonic distortion over the course of the operating torque-speed range. Simulation of the control system on simulated hardware has been carried out in MATLAB; these simulation results verify the theoretical analysis. Then further verified and analysed using the developed laboratory-scale embedded battery MMC prototype

EVALUATING ARTIFICIAL INTELLIGENCE METHODS FOR USE IN KILL CHAIN FUNCTIONS

Current naval operations require sailors to make time-critical and high-stakes decisions based on uncertain situational knowledge in dynamic operational environments. Recent tragic events have resulted in unnecessary casualties, and they represent the decision complexity involved in naval operations and specifically highlight challenges within the OODA loop (Observe, Orient, Decide, and Assess). Kill chain decisions involving the use of weapon systems are a particularly stressing category within the OODA loop—with unexpected threats that are difficult to identify with certainty, shortened decision reaction times, and lethal consequences. An effective kill chain requires the proper setup and employment of shipboard sensors; the identification and classification of unknown contacts; the analysis of contact intentions based on kinematics and intelligence; an awareness of the environment; and decision analysis and resource selection. This project explored the use of automation and artificial intelligence (AI) to improve naval kill chain decisions. The team studied naval kill chain functions and developed specific evaluation criteria for each function for determining the efficacy of specific AI methods. The team identified and studied AI methods and applied the evaluation criteria to map specific AI methods to specific kill chain functions.Civilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyCaptain, United States Marine CorpsCivilian, Department of the NavyCivilian, Department of the NavyApproved for public release. Distribution is unlimited