105 research outputs found
Emerging Power Electronics Technologies for Sustainable Energy Conversion
This Special Issue summarizes, in a single reference, timely emerging topics related to power electronics for sustainable energy conversion. Furthermore, at the same time, it provides the reader with valuable information related to open research opportunity niches
Efficiency and Sustainability of the Distributed Renewable Hybrid Power Systems Based on the Energy Internet, Blockchain Technology and Smart Contracts-Volume II
The climate changes that are becoming visible today are a challenge for the global research community. In this context, renewable energy sources, fuel cell systems, and other energy generating sources must be optimally combined and connected to the grid system using advanced energy transaction methods. As this reprint presents the latest solutions in the implementation of fuel cell and renewable energy in mobile and stationary applications, such as hybrid and microgrid power systems based on the Energy Internet, Blockchain technology, and smart contracts, we hope that they will be of interest to readers working in the related fields mentioned above
Emerging Power Electronics Technologies for Sustainable Energy Conversion
This Special Issue summarizes, in a single reference, timely emerging topics related to power electronics for sustainable energy conversion. Furthermore, at the same time, it provides the reader with valuable information related to open research opportunity niches
Design and Control of Power Converters 2019
In this book, 20 papers focused on different fields of power electronics are gathered. Approximately half of the papers are focused on different control issues and techniques, ranging from the computer-aided design of digital compensators to more specific approaches such as fuzzy or sliding control techniques. The rest of the papers are focused on the design of novel topologies. The fields in which these controls and topologies are applied are varied: MMCs, photovoltaic systems, supercapacitors and traction systems, LEDs, wireless power transfer, etc
POWER QUALITY CONTROL AND COMMON-MODE NOISE MITIGATION FOR INVERTERS IN ELECTRIC VEHICLES
Inverters are widely utilized in electric vehicle (EV) applications as a major voltage/current source for onboard battery chargers (OBC) and motor drive systems. The inverter performance is critical to the efficiency of EV system energy conversion and electronics system electro-magnetic interference (EMI) design. However, for AC systems, the bandwidth requirement is usually low compared with DC systems, and the control impact on the inverter differential-mode (DM) and common-mode (CM) performance are not well investigated. With the wide-band gap (WBG) device era, the switching capability of power electronics devices drastically improved. The DM/CM impact that was brought by the WBG device-based inverter becomes more serious and has not been completely understood.
This thesis provides an in-depth analysis of on-board inverter control strategies and the corresponding DM/CM impact on the EV system. The OBC inverter control under vehicle-to-load (V2L) mode will be documented first. A virtual resistance damping method minimizes the nonlinear load harmonics, and a neutral balancing method regulates the unbalanced load impact through the fourth leg. In the motor drive system, a generalized CM voltage analytical model and a current ripple prediction model are built for understanding the system CM and DM stress with respect to different modulation methods, covering both 2-level and 3-level topologies. A novel CM EMI damping modulation scheme is proposed for 6-phase inverter applications. The performance comparison between the proposed methods and the conventional solution is carried out. Each topic is supported by the corresponding hardware platform and experimental validation
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High performance disturbance observer based control system design for permanent magnet synchronous AC machine applications
This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonAn electrical machine is one of the main workforces in different industries and serves them in various applications. Machine drive control design involves many technical issues for efficient and robust exploitation. Over several decades, Permanent Magnet Synchronous Motor (PMSM) is getting preferred for industrial applications over its counterpart Squirrel Cage Induction Motor (SCIM) drive, because of their higher efficiency, power density, and higher torque to inertia ratio.
In the prospective that PMSM drives are considered the drives of the future, there are still technical challenges and issues related to PMSM control. Many studies have been devoted to PMSM control in the past, but there are still some open research areas that bring worldwide researchers’ interests back to PMSM drive control. One of the approaches that may facilitate better performance, higher efficiency, and robust and reliable work of the control system is the disturbance observer-based control (DOBC) with linear and nonlinear output feedback control for PM synchronous machine applications. DOBC is adopted due to its ability to reject external and internal disturbances with improving tracking performance in the variable speed wind energy conversion system (WECS) to maximize power extraction. The high order disturbance observer (HODO) is utilized to estimate the aerodynamic torque-based wind speed without the use of a traditional anemometer, which reduces the overall cost and improves the reliability of the whole system. Also, this method has been designed to improve the angular shaft speed tracking of the PMSM system under load torque disturbance and speed variations.
The model-based linear and nonlinear feedback control are used in the proposed control systems. The sliding mode control (SMC) with switching output feedback control law and integral SMC with linear feedback and state-dependent Riccati equation (SDRE) based approaches have been designed for the systems. The SDRE control accounts for the nonlinear multivariable structure of the WECS and is approximated with Taylor series expansion terms. The chattering inherited from SMC is eliminated by the continuous approximation technique. The sliding mode is guaranteed by eliminating the reaching mode in the proposed integral SMC. The model-free cascaded linear feedback control system based on the proportional-integral (PI) controllers use a back-calculation algorithm anti-windup scheme. The proposed speed controllers are synthesized with HODO to compensate for the external disturbance, model uncertainty, noise, and modelling errors. Moreover, servomechanism-based SDRE control, a near-optimal control system is designed to suppress the model uncertainty and noise without the use of disturbance observers.
The proposed control systems for PMSM speed regulation have demonstrated a significant improvement in the angular shaft speed-tracking performance at the transients. Their performances have been tested under speed, load torque variations, and model uncertainty. For example, HODO-based SMC with switching output feedback control law (SOFCL) has demonstrated improvement by more than 78% than the PI-PI control system of the PMSM. The performance of the HODOs-based Integral SMC with SDRE nonlinear feedback is improved by 80.5% under external disturbance, model uncertainty, and noise than Integral SMC with linear feedback in the WECS. The HODO-based SDRE control with servomechanism has shown an 80.2% improvement of mean absolute percentage error under disturbances than Integral SMC with linear feedback in the WECS. The PMSM speed tracking performance of the proposed HODO-based discrete-time PI-PI control system with back-calculation algorithm anti-windup scheme is improved by 87.29% and 90.2% in the speed commands and load torque disturbance variations scenarios respectively. The simulations for testing the proposed control system of the PMSM system and WECS have been implemented in Matlab/Simulink environment. The PMSM speed control experimental results have been obtained with Lucas-Nuelle DSP-based rapid control prototyping kit.Center for International Program “Bolashak” of the Ministry of Education and Science Republic of Kazakhsta
A seven-level cascaded multilevel inverter based on simplified SVPWM method
The multilevel converters are extremely widespread alternatives within megawatt power level as well as medium voltage level applications due to their excellent execution than the typical two-level converters. The widely applied control strategies aimed at inverters are Sine Pulse Width Modulation (SPWM) and Space Vector Pulse Width Modulation (SVPWM) strategies. In between these two PWM methods, the SVPWM strategy has excellent execution as compared to the SPWM strategy as a result of improved DC link voltage use as well as a decrease in Total Harmonic Distortion (THD) in output voltages. A traditional SVPWM strategy owns numerous weaknesses like computational complications in terms of identification of the reference voltage vector position, to identify sector, triangle and also it requires large memory for storing look up tables used for switching vectors. This paper presents, an innovative modified SVPWM strategy aimed at Cascaded H-Bridge Multilevel Inverter (CHBMLI). The novel modified SVPWM strategy has overwhelm the downsides of traditional SVPWM strategy. A seven-level CHBMLI is used for the implementation of this simplified SVPWM method to assess performance and as well to made comparison with the SPWM strategy. A MATLAB software is used for the simulation
Industrial and Technological Applications of Power Electronics Systems
The Special Issue "Industrial and Technological Applications of Power Electronics Systems" focuses on: - new strategies of control for electric machines, including sensorless control and fault diagnosis; - existing and emerging industrial applications of GaN and SiC-based converters; - modern methods for electromagnetic compatibility. The book covers topics such as control systems, fault diagnosis, converters, inverters, and electromagnetic interference in power electronics systems. The Special Issue includes 19 scientific papers by industry experts and worldwide professors in the area of electrical engineering
Performance enhancement of direct torque control induction motor drive using space vector modulation strategy
Purpose. The main objective of this work is to demonstrate the advantages brought by the use of space vector modulation technique in the direct torque control of the induction motor. To achieve this purpose, two different direct torque control approaches (with space vector modulation) are proposed and studied from a comparative aspect with each other and with the conventional direct torque control. The novelty of this work consists in the employment of an Integral-Proportional (IP) speed controller in the two proposed direct torque control approaches and a more in-depth evaluation for their performance mainly the switching frequency of inverter semiconductor components and motor torque ripples. Methods. Two different direct torque control approaches that use the space vector modulation strategy and/or fuzzy-logic control, are described in detail and simulated with IP speed controller. The simulation experiments are carried out using Matlab/Simulink software and/or fuzzy-logic tools. Results. Practical value. Comparison results show that the two proposed direct torque control structures (with space vector modulation) exhibit a large reduction in torque ripples and can also avoid random variation problem of switching frequency (over a wide range of speed or torque control). On the other hand, the use of IP speed regulator ensured good dynamic performance for the drive system as well as considerably minimized peak overshoot in the speed response. Practically all of these benefits are achieved while retaining the simplicity and the best dynamic characteristics of the classical direct torque control, especially with the modified direct torque control approach in which the design or implementation requires minimal computational effort.Мета. Основна мета даної роботи – продемонструвати переваги використання методу модуляції просторового вектора при прямому регулюванні крутного моменту асинхронного двигуна. Для досягнення цієї мети запропоновано два різних підходи до прямого управління крутним моментом (з модуляцією просторового вектора), які досліджуються з порівняльної точки зору одного з іншим, а також зі звичайним прямим керуванням крутним моментом. Новизна роботи полягає у використанні інтегрально-пропорційного (IП) регулятора швидкості в двох запропонованих підходах до прямого регулювання крутного моменту та більш поглибленій оцінці їх ефективності, головним чином, частоти перемикань напівпровідникових компонентів інвертора та пульсації крутного моменту двигуна. Методи. Два різних підходи до прямого керування крутним моментом, які використовують стратегію модуляції просторового вектора та/або керування нечіткою логікою, детально описані та змодельовані за допомогою ІП-регулятора швидкості. Обчислювальні експерименти проводяться з використанням програмного забезпечення Matlab/Simulink та/або інструментів нечіткої логіки. Результати. Практична цінність. Результати порівняння показують, що дві запропоновані структури прямого керування крутним моментом (з модуляцією просторового вектора) демонструють значне зниження пульсації крутного моменту, а також можуть уникнути проблеми випадкових змін частоти перемикання (у широкому діапазоні регулювання швидкості або крутного моменту). З іншого боку, використання ІП-регулятора швидкості забезпечило хороші динамічні характеристики для приводної системи, а також значно знизило пікове перевищення швидкості. Практично всі ці переваги досягаються при збереженні простоти та найкращих динамічних характеристик класичного прямого керування крутним моментом, особливо з модифікованим підходом прямого керування крутним моментом, при якому проектування або впровадження вимагає мінімальних обчислювальних витрат
A comprehensive review on modular multilevel converters, submodule topologies, and modulation techniques
The concept of the modular multilevel converter (MLC) has been raising interest in research in order to improve their performance and applicability. The potential of an MLC is enormous, with a great focus on medium- and high-voltage applications, such as solar photovoltaic and wind farms, electrified railway systems, or power distribution systems. This concept makes it possible to overcome the limitation of the semiconductors blocking voltages, presenting advantageous characteristics. However, the complexity of implementation and control presents added challenges. Thus, this paper aims to contribute with a critical and comparative analysis of the state-of-the-art aspects of this concept in order to maximize its potential. In this paper, different power electronics converter topologies that can be integrated into the MLC concept are presented, highlighting the advantages and disadvantages of each topology. Nevertheless, different modulation techniques used in an MLC are also presented and analyzed. Computational simulations of all the modulation techniques under analysis were developed, based on four cascaded full-bridge topologies. Considering the simulation results, a comparative analysis was possible to make regarding the symmetry of the synthesized waveforms, the harmonic content, and the power distribution in each submodule constituting the MLC.This work has been supported by FCT—Fundação para a Ciência e Tecnologia, within the
R&D Units Project Scope UIDB/00319/2020. Mr. Luis A. M. Barros is supported by the doctoral
scholarship PD/BD/143006/2018, granted by the Portuguese FCT foundation
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