Authors:
Saeed Arazm;Kamal Al-Haddad;
Pages: 1 - 13 Abstract: A new configuration of three-phase Wye Packed U-cells (Y-PUC) with a single DC source is proposed in this paper. In fact, this configuration represents a single DC source modular three-phase PUC converter. The DC source on PUC topology is replaced by a flying capacitor to obtain a suitable submodule. Moreover, the modularity of the Y-PUC configuration makes it an appropriate alternative for MMC applications. Furthermore, the proposed structure is an advantageous configuration for high voltage applications such as high voltage direct current (HVDC) transmission lines with the capability of DC fault handling. All PUC topologies such as PUC5, PUC7, PUC9, PUC15 can be replaced in the modules of this proposed single-phase and three-phase configuration to multiply the load voltage levels for improving the output waveform. Active voltage balancing technique through carrier-based modulation is applied. System modeling and operating sequences are developed. Simulation and experimental results are presented and discussed to validate the performance of the proposed structure. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Mahin K. Atiq;Raheeb Muzaffar;Óscar Seijo;Iñaki Val;Hans-Peter Bernhard;
Pages: 14 - 36 Abstract: Many emerging applications require a higher level of flexibility, modularity, and efficiency but are dependent on advancements in communication infrastructure and distributed computing. Time-sensitive networking (TSN) standards aim at providing vendor agnostic, reliable, and deterministic communications over the Ethernet, but lack in flexibility and modularity provisions. In this context wireless communication systems are preferred given the obvious benefits in terms of increased flexibility, reduced deployment & maintenance costs, and inherent mobility support. However, the stochastic nature of the wireless medium poses several challenges in achieving these benefits. In this paper we comprehensively analyze the recent standardization efforts and developments in IEEE 802.11 and 5G to enable low-latency, deterministic communications and present the current status of their integration with wired TSN. Then, we present a set of use cases that may be enabled by wireless TSN including industrial automation, automotive, or audiovisual applications. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Gayan Watthewaduge;Berker Bilgin;
Pages: 37 - 49 Abstract: Acoustic noise and vibration is one of the shortcomings of a switched reluctance machine (SRM). Harmonics of the radial force waveform in the airgap excite the stator structure at different vibration modes with specific frequencies. The radial force density in the airgap should be calculated before analyzing and mitigating acoustic noise and vibration. This paper proposes a reluctance mesh-based magnetic equivalent circuit (MEC) model to calculate the airgap radial force density. Reluctance mesh-based MEC models are developed for 3-phase 6/4, 6/16, 12/8 and 4-phase 8/6, 8/10, and 16/12 SRMs. A technique for the dynamic modeling of SRMs is proposed using the reluctance mesh-based MEC method. Dynamic currents are calculated using the proposed technique and, then, the radial and tangential flux density in the airgap are calculated. The radial force density in the airgap is calculated by applying the Maxwell Stress Tensor method. Fourier series is used to calculate the harmonics of the radial force density. The results obtained from the MEC model are verified using finite element method (FEM) models. The implemented MEC-based dynamic modeling method is validated using experimental results. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Nikolai Galkin;Chen-Wei Yang;Yulia Berezovskaya;Mattias Vesterlund;Valeriy Vyatkin;
Pages: 50 - 64 Abstract: Datacentres are becoming a sizable part of the energy system and are one of the biggest consumers of the energy grid. The so-called “Green Datacentre” is capable of not only consuming but also producing power, thus becoming an important kind of prosumers in the electric grid. Green datacentres consist of a microgrid with a backup uninterrupted power supply and renewable generation, e.g., using photovoltaic panels. As such, datacentres could realistically be important participants in demand/response applications. However, this requires reconsidering their currently rigid control and automation systems and the use of simulation models for online estimation of the control actions impact. This paper presents such a microgrid simulation model modelled after a real edge datacentre. A case study consumption scenario is presented for the purpose of validating the developed microgrid model against data traces collected from the green edge datacentre. Both simulation and real-time validation tests are performed to validate the accuracy of the datacentre model. Then the model is connected to the automation environment to be used for the online impact estimation and virtual commissioning purposes. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Chengjun Shen;Saeed Jahdi;Juefei Yang;Olayiwola Alatise;Jose Ortiz-Gonzalez;Ruizhu Wu;Phil Mellor;
Pages: 65 - 80 Abstract: The 4H-SiC vertical NPN BJTs are attractive power devices with potentials to be used as high power switching devices with high voltage ratings in range of 1.7 kV and high operating temperatures. In this paper, the advantages of the 4H-SiC NPN BJTs in terms of switching transients and current gain over their silicon counterparts is illustrated by means of extensive experimental measurements and modelling, including investigation of high level injection, as a common phenomenon in bipolar devices that influences the switching rates and DC current gain. The two device types have been tested at 800 V with maximum temperature of 175 °C and maximum collector current of 8 A. The turn-ON and turn-OFF transition in Silicon BJT is seen to be much slower than that of the SiC BJT while the transient duration will increase with increasing temperature and decreases with larger collector currents. The common-emitter current gain of SiC BJT is also found to be much higher than silicon counterparts, increasing with temperature in low injection levels but decreasing in higher injection levels in both devices. The rate of increase of current gain slows down toward stability as the collector current increases, known as the high-level injection. Current sharing imbalance among parallel connected devices is also investigated, which are shown to be evidently dependant on temperature and base resistance in Silicon BJT, while the current collapse in also seen in SiC BJT at high injection levels with high base resistance. The turn-OFF delay is seen to be temperature dependant in single and paralleled Silicon BJTs while almost non-existent in SiC device. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Pranoy Roy;JiangBiao He;Tiefu Zhao;Yash Veer Singh;
Pages: 81 - 104 Abstract: A hybrid renewable energy source (HRES) consists of two or more renewable energy sources, suchas wind turbines and photovoltaic systems, utilized together to provide increased system efficiency and improved stability in energy supply to a certain degree. The objective of this study is to present a comprehensive review of wind-solar HRES from the perspectives of power architectures, mathematical modeling, power electronic converter topologies, and design optimization algorithms. Since the uncertainty of HRES can be reduced further by including an energy storage system, this paper presents several hybrid energy storage system coupling technologies, highlighting their major advantages and disadvantages. Various HRES power converters and control strategies from the state-of-the-art have been discussed. Different types of energy source combinations, modeling, power converter architectures, sizing, and optimization techniques used in the existing HRES are reviewed in this work, which intends to serve as a comprehensive reference for researchers, engineers, and policymakers in this field. This article also discusses the technical challenges associated with HRES as well as the scope of future advances and research on HRES. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Lynn Verkroost;Thymen Vandenabeele;Peter Sergeant;Hendrik Vansompel;
Pages: 105 - 115 Abstract: Because a modular motor drive is composed of multiple identical pole drive units and controllers, it can be considered as a multi-agent system. This makes modular motor drives particularly interesting during faults, when the remaining healthy agents assure the continuity of operation. Nevertheless, for some crucial information such as the rotor position, these drives still rely on a single sensor which introduces a single point of failure. In this work, this single high-resolution position sensor is replaced by multiple binary, low-resolution position sensors. A vector tracking observer algorithm, implemented in the different controllers, processes this low-resolution sensor data into a position estimate. Subsequently, these position estimates of the different agents are exchanged with other agents using a distributed averaging algorithm. For this latter approach, it is shown in this work that it improves the position estimation under healthy conditions as well as during agent malfunctions. The concept is demonstrated on a modular axial-flux permanent magnet synchronous machine with fifteen pole drive units, each equipped with a low-resolution position sensor, that are assigned to five agents. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Sho Sakaino;Kazuki Fujimoto;Yuki Saigusa;Toshiaki Tsuji;
Pages: 116 - 127 Abstract: Thegeneration of robot motions in the real world is difficult by using conventional controllers alone and requires highly intelligent processing. In this regard, learning-based motion generations are currently being investigated. However, the main issue has been improvements of the adaptability to spatially varying environments, but a variation of the operating speed has not been investigated in detail. In contact-rich tasks, it is especially important to be able to adjust the operating speed because a nonlinear relationship occurs between the operating speed and force (e.g., inertial and frictional forces), and it affects the results of the tasks. Therefore, in this study, we propose a method for generating variable operating speeds while adapting to spatial perturbations in the environment. The proposed method can be adapted to nonlinearities by utilizing a small amount of motion data. We experimentally evaluated the proposed method by erasing a line using an eraser fixed to the tip of the robot as an example of a contact-rich task. Furthermore, the proposed method enables a robot to perform a task faster than a human operator and is capable of operating close to the control bandwidth. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
An Ngoc Lam;Oystein Haugen;Jerker Delsing;
Pages: 128 - 145 Abstract: The Industrial Internet of Things (IIoT) enables the integration of physical devices such as sensors and actuators into the virtual world of automation application systems via different communication protocols. Interoperability among the “things” appears to be one of the biggest conceptual and technological challenges in developing the IIoT framework. Typically, collaboration at the field device level is very limited. Instead, the decision-making process is usually propagated to higher levels with substantial computational resources. This centralized architecture has been widely deployed based on global cloud infrastructure. However, sending data over the cloud for analysis may bring about privacy and security threats. Besides, network latency could be another factor that reduces adaptability. In this article, we propose a decentralized approach that applies the concepts of local automation cloud. By using semantic technologies to achieve autonomicity, the approach enables real-time monitoring of the control systems within one local cloud and automates orchestration and configuration locally through adaptation based on semantic policies. The approach is deployed and tested on a chemical production use case in which business-level policies have been used for dynamical planning for suppliers and automatic detection of malfunctioning sensors with subsequent adaptation to continuing supply planning and production as smooth as possible. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Wael Alsabbagh;Peter Langendöerfer;
Pages: 146 - 162 Abstract: Programmable Logic Controllers (PLCs) are increasingly connected and integrated into the Industrial Internet of Things (IIoT) for a better network connectivity and a more streamlined control process. But in fact, this brings also its security challenges and exposes them to various cyber-attacks targeting the physical process controlled by such devices. In this work, we investigate whether the newest S7 PLCs are vulnerable by design and can be exploited. In contrast to the typical control logic injection attacks existing in the research community, which require from adversaries to be online along the ongoing attack, this article introduces a new exploit strategy that aims at disrupting the physical process controlled by the infected PLC when adversaries are not connected neither to the target nor to its network at the point zero for the attack. Our exploit approach is comprised of two steps: 1) Patching the PLC with a malicious Time-of-Day interrupt block once an attacker gains access to an exposed PLC, 2) Triggering the interrupt at a later time on the attacker will, when he is disconnected to the system’s network. For a real attack scenario, we implemented our attack approach on a Fischertechnik training system based on S7-1500 PLC using the latest version of S7CommPlus protocol. Our experimental results showed that we could keep the patched interrupt block in idle mode and hidden in the PLC memory for a long time without being revealed before being activated at the specific date and time that the attacker defined. Finally, we suggested some potential security recommendations to protect industrial environments from such a threat. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Yicheng Liao;Henrik Sandberg;Xiongfei Wang;
Pages: 163 - 173 Abstract: Power systems equipped with power electronic converters can be modeled by harmonic transfer functions (HTFs) in a black-box manner for dynamic analysis. This paper studies the truncation of HTFs. It is proposed to define the gain function of an HTF as the norm of its central-column vector. Then, the error bound of the gain function in relation to the truncation order is explicitly derived, which can be used as an indicator for the HTF truncation. Compared with existing solutions, the proposed method is practical in truncating black-box systems with unknown internal parameters, since the truncation error bound can be estimated by the central-column elements of the HTF, which can be easily measured through frequency scan. The truncation approach is finally verified on a three-phase electronic power system by electromagnetic transient simulations. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Jonas Queiroz;Paulo Leitão;Eugénio Oliveira;
Pages: 174 - 187 Abstract: The ongoing 4th industrial revolution is characterized by the digitization of industrial environments, mainly based on the use of Internet of Things, Cloud Computing and Artificial Intelligence (AI). Regarding AI, although data analysis has shown to be a key enabler of industrial Cyber-Physical Systems (CPS) in the development of smart machines and products, the traditional Cloud-centric solutions are not suitable to attend the data and time-sensitive requirements. Complementary to Cloud, Edge Computing has been adopted to enable the data processing capabilities at or close to the physical components. However, defining which data analysis tasks should be deployed on Cloud and Edge computational layers is not straightforward. This work proposes a framework to guide engineers during the design phase to determine the best way to distribute the data analysis capabilities among computational layers, contributing for a lesser ad-hoc design of distributed data analysis in industrial CPS. Besides defining the guidelines to identify the data analysis requirements, the core contribution relies on a Fuzzy Logic recommendation system for suggesting the most suitable layer to deploy a given data analysis task. The proposed approach is validated in a smart machine testbed that requires the implementation of different data analysis tasks for its operation. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Juefei Yang;Saeed Jahdi;Bernard Stark;Olayiwola Alatise;Jose Ortiz-Gonzalez;Ruizhu Wu;Phil Mellor;
Pages: 188 - 202 Abstract: In this paper, the crosstalk-induced shoot-through current and induced gate voltage of SiC planar MOSFETs, SiC symmetrical double-trench MOSFETs and SiC asymmetrical double-trench MOSFETs is investigated on a half-bridge circuit to analyse the impact of temperature, drain-source voltage switching rate, gate resistance and load current level on crosstalk-induced properties of different SiC MOSFET structures. It shows that due to the smaller gate-source capacitance, the two double-trench MOSFETs exhibit higher induced gate voltage during crosstalk with the same external gate resistance, which together with the higher transconductance, yield higher shoot-through current than the planar MOSFET. Accordingly, their shoot-through current decreases with increasing of the load current while the planar MOSFET exhibits an opposite trend. The different trend of shoot-through current with temperature on DUTs reveals that the crosstalk in different device structures are dominated by different mechanisms, i.e. threshold voltage and channel mobility with the gate-source capacitance influencing the amplitude. Impact of bias temperature instability with positive and negative gate stressing is measured with a range of stress and recover periods at temperateness ranging between 25 °C to 175 °C. These measurements show that the peak shoot-through correlates with the threshold drift, though with less sensitivity for SiC symmetrical and asymmetrical double-trench MOSFETs compared with the planar SiC MOSFET where the inter-dependence is pronounced. A model is developed for the induced gate voltage and shoot-through current during crosstalk with channel current considered. The comparison of the model results with measurement confirms its capability to predict crosstalk in different MOSFET structures. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Gautam Rituraj;Gautham Ram Chandra Mouli;Pavol Bauer;
Pages: 203 - 222 Abstract: In recent years, the research interest in off-grid (standalone mode) and hybrid (capable of both standalone and grid-connected modes) charging systems for electric vehicles (EVs) has increased. The main reason is to provide a seamless charging infrastructure in urban and rural areas where the electrical grid is unreliable or unavailable so that EV adoption can be increased worldwide. In this regard, this article reviews the state-of-the-art architectures of the off-grid and hybrid charging systems and investigates their various subsystems, such as single or multiple energy sources, power electronics converters, energy storage systems, and energy management strategies. These subsystems should be optimally integrated and operated to achieve low-cost and efficient EV charging. Moreover, each subsystem is explored in detail to find the current status and technology trends. Furthermore, EV charging connectors, their power level, and standards for all kinds of EVs (ranging from one-wheeler to four-wheelers) are reviewed, and suggestions are discussed related to the non-standardization of charging plugs. Finally, conclusions show the continuous efforts of the researchers in improving the systems in various aspects, such as cost reduction, performance improvement, longevity, negative environmental effect, system size minimization, and efficient operation, and highlight challenges for both charging systems. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Tomás P. Corrêa;Luis Almeida;
Pages: 223 - 235 Abstract: Several authorsinvestigated the use of internal digital communication networks in Modular Multilevel Converters. The first works in this area keep a centralized control scheme, but they struggle to reach the fast cycle times required for achieving goodcontrol performance, specially as the number of cells increases. To reduce the network cycle time, some authors adopted a partly decentralized control scheme. However, those proposals restrict the capacitorbalancing to a closed-loop strategy and the use of carrier-based modulation. This work introduces DiSortNet, a novel Ethernet-based ring network protocol that achieves low cycle times while preserving the centralized control scheme and its modulation flexibility. DiSortNet emerges from a communications-control co-design approach, which main feature is the distributed sorting of capacitor voltages. We show that distributed sorting implies a marginal degradation in the balancing of capacitor voltages while bounding the network payload and reducing the cycle time. Implementation-wise, using FPGA-based network interfaces, DiSortNet achieves half the cycle-time obtained with EtherCAT in a network with 86 nodes and less than half for larger networks, reaching 157 μs with 300 nodes. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Wiljan Vermeer;Gautham Ram Chandra Mouli;Pavol Bauer;
Pages: 236 - 251 Abstract: This paper proposes a method for optimally dimensioning the components of a prosumer energy management system that integrates photovoltaic (PV) panels, multiple bidirectional electric vehicle chargers, an inverter, and a battery energy storage charger. Besides optimally dimensioning the components, it also optimizes power management while integrating the frequency containment reserve market and Li-ion battery degradation. The results show that the integration of the frequency containment reserve (FCR) market can increase lifetime cost savings by 36%, compared to optimal power management alone and up to 460% compared to non-optimal power management. Furthermore, the effects of PV and battery energy storage (BES) degradation on reservable capacity are analyzed including the importance of battery second-life value on lifetime net present cost is investigated. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Rosario V. Giuffrida;Spasoje Mirić;Johann W. Kolar;Dominik Bortis;
Pages: 252 - 264 Abstract: This paper investigates the design of an Eddy Current Sensor (ECS) for position measurement of a moving conductive target located behind a fixed conductive shielding surface. Such a sensor can e.g. be used in completely sealed actuators with magnetically levitated rotor or mover for high purity applications. Starting from the analysis of the sensor’s operating principle, the design of the excitation coil, the achievable sensitivity and bandwidth as well as the temperature stability of the sensor are investigated. Subsequently, a suitable sensor interface, consisting of the driving and signal conditioning electronics, is selected. With this it is possible to distinguish between position and temperature variations, for which the optimal operational frequencies are identified. The results are finally verified with measurements on a hardware sensor prototype, showing that the ECS can achieve a sensitivity of 1 mV/µm, a position resolution of 1 µm, with a measurement bandwidth of 30 kHz and can hence be used to capture the mover’s position in an active magnetic bearing feedback control structure. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Shih-Wei Su;Christoph M. Hackl;Ralph Kennel;
Pages: 265 - 282 Abstract: Physically motivated and analytical prototype functions are proposed to approximate the nonlinear flux linkages of nonlinear synchronous machines (SMs) in general; and reluctance synchronous machines (RSMs) and interior permanent magnet synchronous machines (IPMSMs) in particular. Such analytical functions obviate the need of huge lookup tables (LUTs) and are beneficial for optimal operation management and nonlinear control of such machines. The proposed flux linkage prototype functions are capable of mimicking the nonlinear self-axis and cross-coupling saturation effects of SMs. Moreover, the differentiable prototype functions allow to easily derive analytical expressions for the differential inductances by simple differentiation of the analytical flux linkage prototype functions. In total, two types of flux linkage prototype functions are developed. The first flux linkage approximation is rather simple and obeys the energy conservation rule for “symmetric” flux linkages of RSMs. With the gained knowledge, the second type of prototype functions is derived in order to achieve approximation flexibility necessary for SMs with permanent (or electrical) excitation with “unsymmetric” flux linkages due to the excitation offset. All proposed flux linkage prototype functions are continuously differentiable, obey the energy conservation rule and, as fitting results show, achieve a (very) high approximation accuracy over the whole operation range. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Giuseppe Buja;Simone Castellan;Qingsong Wang;
Pages: 283 - 290 Abstract: Reactive electric spring (RES) is a technique aimed at stabilizing the user voltage in presence of grid voltage variations by means of a user-encapsulated circuit. In spite of the numerous papers on the matter, no expressions are still available to size the RES elements. This paper fills this lack, by drawing up a sizing procedure of them. The procedure starts with a targeted investigation of the RES operation and exploits the outcomes to provide expressions for the values of the passive elements as well as for the voltage-current ratings of the voltage source inverter (VSI). The sizing expressions are formulated in normalized form to emphasize their dependence on the parameters of the user non-critical load. Focus of the sizing procedure is on the two RES key-elements, namely the AC-side capacitor and VSI but the AC filter inductor and the DC-side capacitor are also sized. Two options for sizing the AC-side capacitor are also discussed. At last, the study case of a user supplied by a low-voltage distribution line is considered and the sizing expressions are utilized to calculate the RES data. Experimental results, obtained by an on-purpose arranged hardware-in-the-loop (HIL) rig, validate the sizing procedure. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Xing Yang;Lei Shu;Kailiang Li;Zhiqiang Huo;Yu Zhang;
Pages: 291 - 303 Abstract: Sensor faults can produce abnormal and spurious observations in the solar insecticidal lamp Internet of Things (SIL-IoTs) system. Early detection and identification of the sensor node’s abnormality are critical to ensure the SIL-IoTs system’s reliability. In this study, we propose a lightweight separable 1D convolution neural network that can be implemented in SIL-IoTs nodes to identify sensor faults, reduce detecting delay, and decrease data transmission. However, the reliability of data acquired by sensors is decreased because a SIL-IoTs node releases high voltage pulse discharge (a kind of electromagnetic interference) when pests collide with its metal mesh. This kind of data fluctuation impacts fault diagnosis accuracy. Consequently, fault-related feature maps and temporal signals are characterized via a novel time and channel attention module (TCAM) method, which contributes to separating electromagnetic interference noise from sensor faults of SIL-IoTs nodes. A real-world testbed is applied to validate the effectiveness of the proposed method on sensor fault diagnosis in the SIL-IoTs system. Experimental results demonstrate that the proposed method can detect four typical sensor faults with the best trade-off between accuracy (99.9% average accuracy and 97.6% average F1-score) and efficiency (351 KB inference model size and 4.33 W average energy consumption on Raspberry Pi). PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Jinyong Yu;Mengmeng Liu;Juan J. Rodríguez-Andina;
Pages: 304 - 317 Abstract: By Markov jump systems (MJSs) modeling, this article investigates event-triggered asynchronous fault detection (FD) for quarter-car suspension system (QCSS) via zonotopic residual evaluation (RE). To save communication resources, a stochastic dynamic event-triggered scheme (DETS) is developed to transmit necessary sampled signals while considering deception attacks (DAs) during signal transmission. By means of the hidden Markov model (HMM) with partially accessible mode information, the asynchronization phenomenon between the original system and the FD filter (FDF) as well as the event generator is fully characterized. In such a framework, a mixed $l_{1}/H_{infty }$ asynchronous FDF design criterion is derived to guarantee the resultant residual system is sensitive to system fault while being robust to amplitude-bounded exogenous disturbances and measurement noise. Compared with existing results, the proposed approach avoids the mode synchronization limitation and the requirement of ideally known probability information in the transformed probability matrix and conditional probability matrix, and thus can be better applied to practical engineering while covering some previous works as special cases. Moreover, for the first time, a novel zonotope-based dynamic threshold evaluation approach is developed for FD in MJSs instead of the traditional constant threshold scheme for RE. Such an algorithm is designed to effectively avoid inappropriate human empirical threshold selection, which can both shorten the FD time and avoid false alarms hence ensuring satisfactory FD performance. Finally, a quarter-car suspension system is utilized to demonstrate the effectiveness of the proposed design strategy. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Aida Akbarzadeh;Sokratis Katsikas;
Pages: 318 - 328 Abstract: Cyber-Physical Systems (CPSs) engineering profoundly relies on modeling methods to represent the system and study the operation and cybersecurity of CPSs. The operation of a CPS is the result of the collaboration between Information Technology (IT) and Operational Technology (OT) components. While OT focuses on the system’s process physics, the emphasis of IT is on information flow. Consequently, different system models are utilized to study various aspects of CPSs, which may infer different views of the same system. The increasing complexity of CPSs and the high number of cyberattacks against Industrial Control Systems (ICSs) and CPSs in recent years have highlighted the necessity of considering these interrelations based on a unified model to analyze cybersecurity of CPSs. However, the diversity of engineering fields and implicit relations and dependencies between them have made it difficult to integrate the modeling methods towards a unified IT&OT model of CPSs.In this paper, we propose a comprehensive method, based on bond graphs, to model CPS and analyze their cybersecurity. Unlike existing methods, modeling the cyber layer along with the physical layer based on the system flow provides a holistic graphical representation of a CPS, which facilitates collaboration between IT and OT experts. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Anton Dianov;
Pages: 329 - 338 Abstract: Nowadays the percentage of power electronic devices, which use shunts for sensing of electrical signals, is increasing significantly. This method of measurements is simple, reliable and low-cost, however it requires careful elaboration of schematics and meticulous design of printed circuit boards. The author provides a detailed insight into the design of power converter Printed Circuit Boards (PCBs) with shunt-based sensing circuits and provides recommendations on improvement of signal measurements. He analyses the most popular design mistakes and illustrates their impact on measuring signals, which can be used for mistake localization. This paper demonstrates that the properly designed schematic can be turned into poorly operating PCB and recommends measures to avoid it. The author shares his more than 20-years experience and illustrates his statements with examples from real life. Although this paper is mainly addressed to young engineers, it could also be useful for experienced researchers, who work in neighboring areas and do not gain experience in PCB design. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Lucia Beloqui Larumbe;Zian Qin;Pavol Bauer;
Pages: 339 - 352 Abstract: In this article, the Linear Time Invariant (LTI) and Linear Time Periodic (LTP) models of two different implementations of the DDSRF-PLL in the presence of voltage imbalance are derived analytically. The accuracy of the models is investigated with time domain simulations, frequency scans, and stability analysis. On top of this, a guideline for properly choosing between LTI and LTP models for stability assessment of the DDSRF-PLL according to the degree of grid voltage imbalance is proposed. Furthermore, it is revealed that, depending on the DDSRF-PLL implementation, the positive-sequence voltage might also cause LTP dynamics, rendering the LTI model inaccurate even when the imbalance is low. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
H. S. Hewawasam;M. Yousef Ibrahim;Gayan Kahandawa Appuhamillage;
Pages: 353 - 365 Abstract: Mobile robots have been making a significant contribution to the advancement of many sectors including automation of mining, space, surveillance, military, health, agriculture and many more. Safe and efficient navigation is a fundamental requirement of mobile robots, thus, the demand for advanced algorithms rapidly increased. Mobile robot navigation encompasses the following four requirements: perception, localization, path-planning and motion control. Among those, path-planning is a vital part of a fast, secure operation. During the last couple of decades, many path-planning algorithms were developed. Despite most of the mobile robot applications being in dynamic environments, the number of algorithms capable of navigating robots in dynamic environments is limited. This paper presents a qualitative comparative study of the up-to-date mobile robot path-planning methods capable of navigating robots in dynamic environments. The paper discusses both classical and heuristic methods including artificial potential field, genetic algorithm, fuzzy logic, neural networks, artificial bee colony, particle swarm optimization, bacterial foraging optimization, ant-colony and Agoraphilic algorithm. The general advantages and disadvantages of each method are discussed. Furthermore, the commonly used state-of-the-art methods are critically analyzed based on six performance criteria: algorithm’s ability to navigate in dynamically cluttered areas, moving goal hunting ability, object tracking ability, object path prediction ability, incorporating the obstacle velocity in the decision, validation by simulation and experimentation. This investigation benefits researchers in choosing suitable path-planning methods for different applications as well as identifying gaps in this field. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Naoki Motoi;Mathis Nalbach;Shingo Ito;Philipp J. Thurner;Georg Schitter;
Pages: 366 - 374 Abstract: Collagen is a major structural protein in the human body. It not only provides connective tissues such as ligaments and tendons with toughness and strength but it also constitutes the biomechanical scaffold for cell attachment in the extracellular matrix. Collagen molecules aggregate to form collagen fibrils, which are fibers with a diameter of 10 $rm {nm}$ to 500 $rm {nm}$ and a length of up to a centimeter. Tensile tests on individual collagen fibrils reveal a strongly non-linear stress-response to deformation with the tensile modulus reaching the gigapascal range. But not only that, collagen fibrils have been found to be viscoelastic which means collagen fibrils have both elastic and viscous characteristics. However, direct measurement of viscoelastic material properties in tension is only possible with force-controlled tensile tests, which can not be conducted with state-of-the-art methods. In this paper, we report the first force-controlled tensile tests of individual collagen fibrils. To account for the non-linear material characteristics, high responsiveness in the force control and robustness about a property change of the collagen fibril are needed. Therefore, a two-degrees-of-freedom (2-DOF) controller is applied for force control with high responsiveness. The 2-DOF controller is composed of feedforward (FF) and feedback (FB) controllers. In addition, a modeling error compensation is implemented for robustness. The modeling error is calculated from the difference between the actual force response measured by the sensor and the ideal force response calculated from the plant model. The validity of the proposed control method is confirmed from simulation and experimental results. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Jinhua She;Hipólito Guzmán-Miranda;Victor Huang;Allen C. Chen;Stamatis Karnouskos;Larisa Dunai;Chengbin Ma;Alin Tisan;Sho Yokota;
Pages: 375 - 391 Abstract: How to build a sustainable society in view of industrial electronics has been discussed from energy, information and communication technologies, cyber-physical systems (CPSs), and other viewpoints. This paper presents a cross-disciplinary view that integrates the fields of human factors, professional education, electronic systems on chip, resilience and security for industrial applications, technology ethics and society, and standards. After explaining the efforts and challenges in these fields, this paper shows a methodology for cross-disciplinary technology that integrates the technical committees in Cluster 4, Industrial Electronics Society. A project, which was launched in March 2022, implements a ‘Proof of Concept’ trial of the methodology. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Ibrahim Saiful Millah;Pei Cheng Chang;Dawit Fekadu Teshome;Ramadhani Kurniawan Subroto;Kuo Lung Lian;Jia-Fu Lin;
Pages: 392 - 408 Abstract: A partial shading condition (PSC) is one of the most common problems in the photovoltaic (PV) system. It causes the output power of a PV system drastically decrease. Meta-heuristic algorithms (MHA) can track the maximum power point in a power-voltage (P-V) curve with multiple peaks. Grey wolf optimization (GWO) algorithm is a new optimization algorithm based on MHA. It has been used to solve optimization problems in many applications including MPPT for a PV system. However, the accuracy and tracking time in the original GWO (OGWO) can still be further improved for various PSCs. Therefore, there have been some modified grey wolf optimization (MGWO) algorithms proposed to improve the GWO. Nevertheless, only incremental improvement has been made. Therefore, a modified GWO, named enhanced grey wolf optimization (EGWO) is proposed in this paper. The proposed method adds the weighting average, the pouncing behavior and nonlinear convergence factor in the OGWO. In particular, since real wolves may engage in pouncing action when they are hunting, inclusion of pouncing completes the GWO algorithm and yields great improvements. As will be shown via simulation and experiment, the EGWO can drastically reduce the tracking time (up to 45.5% of the OGWO) and the dynamic tracking efficiency can be improved by more than 2%, compared to the OGWO. Moreover, the EGWO achieves the highest maximum power point compared to some of the existing GWO and other swarm based algorithms. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Mostafa I. Marei;Bader N. Alajmi;Ibrahim Abdelsalam;Nabil A. Ahmed;
Pages: 409 - 419 Abstract: This paper introduces an integrated topology of isolated three-port dc-dc converter (TPC) to interface Photovoltaic (PV) and battery for standalone system. To guarantee zero circulating current flow between different ports while permitting bidirectional power flow at the battery port, auxiliary switches are utilized with the active bridges of the proposed TPC topology. In addition, a simple switching scheme based on Pulse Width Modulation (PWM) is proposed for the input ports of the TPC. This action eliminates the need for the phase shift modulation used for conventional isolated TPCs. While the PV port is controlled to track the maximum power point, the battery port is managed to regulate the load voltage. The paper presents the detailed mathematical analysis of the different operation modes of the proposed integrated TPC topology and the estimated control limits during charging and discharging of the battery. Consequently, dynamic limiters for the duty cycle of each port are set. The proposed integrated TPC based PV-battery system is simulated using PSCAD/EMTDC software package to validate the analysis of different operation modes and to assess the dynamic performance of the system. Moreover, experimental results are presented to authenticate different operation modes of the proposed TPC topology and to evaluate the dynamic behavior of the integrated PV-battery system. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Adnan Ahmad;Zian Qin;Thiwanka Wijekoon;Pavol Bauer;
Pages: 420 - 447 Abstract: The emphasis on clean and green technologies to curtail greenhouse gas emissions due to fossil fuel-based economies has originated the shift towards electric mobility. As on-road electric vehicles (EVs) have shown exponential growth over the last decade, so have the charging demands. The provision of charging facilities from the low-voltage network will not only increase the distribution system’s complexity and dynamics but will also challenge its operational capabilities, and large-scale upgrades will be required to meet the inevitably increasing charging demands. An ultra-fast (UF) charging infrastructure that replicates the gasoline refueling network is urgently needed to facilitate a seamless transition to EVs and ensure smooth operation. This paper presents a review of state-of-the-art DC fast chargers, the charging infrastructure’s current status, motivation, and challenges for medium-voltage (MV) UF charging stations (UFCS). Furthermore, we consider the possible UFCS architectures and suitable power electronics topologies for UF charging applications. To address the peak formation issues in the daily load profile and high operational expenses of UFCSs, integration of renewable energy sources and energy storage systems due to their technological and economic benefits is being considered. The benefits of line frequency transformer (LFT) replacement with a solid-state transformer (SST), SST models, SST-based UF chargers, and MV SST-based UFCS architectures, as well as related MV active front-end and back-end power electronics topologies, are presented. Finally, the application of microgrids’ hierarchical control architecture is considered for chargers and system-level control and management of UFCSs. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Mansour Bouzidi;Said Barkat;Abdelbasset Krama;Haitham Abu-Rub;
Pages: 448 - 459 Abstract: Model Predictive Control (MPC) provides various advantages over traditional controllers in power electronics applications. However, reducing the complexity and computational burden of the Finite-control set-model predictive control (FCS-MPC) in multi-leg multilevel inverters is still a challenging task. In this paper, a simplified model predictive direct power control (MPDPC) for a three-level, four-leg grid-connected converter (4L-GCC) is proposed. The main idea of the proposed strategy is to reduce the computational burden of the control algorithm by using only the switching vectors of the first sector to optimize the cost function. The proposed control method can ensure accurate control of active and reactive powers, control of zero-sequence current, as well as DC capacitor voltages balancing without using any weighting factors. Simulation and experimental results are provided to prove the effectiveness and simplicity of the proposed MPC algorithm compared with most-recently proposed solutions. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Fabio Bernardi;Emilio Carfagna;Giovanni Migliazza;Giampaolo Buticchi;Fabio Immovilli;Emilio Lorenzani;
Pages: 460 - 472 Abstract: Hybrid stepper motors are widespread in industrial automation due to their robustness and high torque performance in low speed range, e.g. 3D printers, pick and place, and generally in many low power positioning applications. In order to increase the efficiency and dynamic performance, current/speed/position closed loop controls are implemented for high performance sensored stepper drives. The main challenge comes from the high number of magnetic poles which these motors feature, increasing the ratio between the fundamental and switching frequency. This paper critically evaluates four current control structures based field oriented control: classic PI regulators, sliding mode control, deadbeat predictive current control and model predictive current control. Simulations and experimental results aim to evaluate the dynamic performance, phase current amplitude and distortion in order to support the critical comparison. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Jingfan Hang;Hao Sun;Xinghu Yu;Juan J. Rodríguez-Andina;Xianqiang Yang;
Pages: 473 - 483 Abstract: Sanitary ceramic products, such as toilet and wash basin, are widely used in our daily life. Sanitary ceramics are expected to have some excellent physical properties, such as corrosion resistance, easy cleaning, and low water absorption. However, surface defects in sanitary ceramics are inevitable due to complex production processes and changing production environment. Therefore, surface defect detection must be performed in the manufacturing process of sanitary ceramics. There are many types of surface defects in sanitary ceramics, and different types of defects have large differences in characteristics and scales. Traditional detection methods with artificially designed features and classifiers are difficult to apply in this context. In addition, there are few studies on surface defect detection methods of sanitary ceramics based on deep neural networks. In this article, a lightweight real-time defect detection network based on the lightweight backbone MobileNetV3 is presented. The proposed network achieves multi-scale detection of surface defects in sanitary ceramics with a multi-layer feature pyramid. Combining region proposal network and anchor-free method, real-time defect detection is achieved. Finally, a detection head with channel attention structure and a low-level mixed feature classification strategy is used to perform defect classification with higher accuracy. Experimental results show that the proposed approach achieves at least 22.9% detection speed improvement and 35.0% average precision improvement while reducing memory consumption by at least 8.4% compared with the classic one-stage SSD, YOLO V3 and two-stage Faster R-CNN methods. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Hong Li;Qian Liu;Zhipeng Zhang;Chen Liu;Zhong Li;Zhichang Yang;Trillion Q. Zheng;
Pages: 484 - 495 Abstract: The parameters of DC-DC converters in a cascaded converters system are often set up separately, which may cause instability or even breakdown of the whole system. The traditional Middlebrook impedance stability criterion and Nyquist criterion are based on the small-signal model, where the nonlinear links are ignored or linearized, which, however leads to inaccurate modeling, and the difficulty for analytically obtaining stability range. In this paper, the nonlinear links, i.e., pulse width modulation links, of cascaded DC-DC converters system are first modeled by the describing function (DF); then, a novel stability analysis method for the cascaded DC-DC converters system is proposed by combining the impedance analysis method, Nyquist criterion and DF to accurately determine the stability range of the cascaded converters system. Since the DF method is only used into single converter so far for stability analysis, a source/load converter equivalent method is proposed in this paper to apply DF method into the cascaded converters. To this end, the two-stage cascaded boost converters systems with and without considering the parasitic parameters are taken as examples to conduct the simulation and experiment for verifying the correctness and the accuracy of the proposed DF-based stability analysis method. This work provides an analytical method to determine not only the stable and unstable ranges but also the critical stability range of the cascaded system, as well as provides a reference to quantificationally design the control parameters. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Kuo Feng;Chunhua Liu;
Pages: 496 - 506 Abstract: As microgrids develop rapidly, more inverters are adopted to achieve DC/AC or AC/DC/AC conversion of distributed generators (DGs). The virtual synchronous generator (VSG) control has started to replace the traditional droop control for inverters. In order to restore the frequency to its nominal value, most existing secondary frequency control (SFC) methods are based on frequency measurements. However, while reducing the rate of change of frequency (ROCOF), virtual inertia also slows down the convergence of frequency-based SFC. Therefore, this paper proposes a new distributed hierarchical control for fast frequency restoration. Based on the real-time VSG control at the bottom level, a novel frequency restoration control is designed. The power reference values generated by the proposed control can accelerate the frequency restoration with accurate power sharing. Meanwhile, by designing event-triggering conditions, parallel inverter controllers only need to communicate with neighbors at the event-triggered moments. Simulations have been performed in MATLAB/Simulink environment. Furthermore, the proposed control has also been tested on the experiment platform, which contains practical physical circuits and real-time controllers. Both simulation and experiment results verify the effectiveness of the proposed control strategy. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Michel Piliougine;Rudy Alexis Guejia-Burbano;Giovanni Spagnuolo;
Pages: 507 - 521 Abstract: A photovoltaic array including several modules in series may show mismatching due to discrepancies among the module conditions, mainly due to partial shadowing. Therefore, the shape of the current–voltage curve deeply changes with respect to the one corresponding to uniform operation. This article shows that a small set of points around the maximum power allows us to detect the occurrence of the mismatching. This approach exploits such a limited information to detect if the module is subjected to mismatching, so that the adoption of a GMPPT algorithm can be avoided. The curvature change is identified by using different machine learning techniques: decision trees, multilayer perceptrons, radial basis functions, and support vector machines. To reduce the classification error, before the fitting of the models, we implement a novel process of selection of the training samples based on a self-organizing map. This procedure makes easier the optimization of the number of hidden neurons. The support vector classifier and the multilayer perceptron with one hidden layer outperform the other approaches, being the former better than the last for extreme mismatching. However, the prediction time of this multilayer perceptron is significantly smaller than the required by the support vector machine. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Tutan Debnath;K. Gopakumar;L. Umanand;Dariusz Zielinski;Kaushik Rajashekara;
Pages: 522 - 536 Abstract: This article proposes a multilevel inverter topology with single dc-link and series-connected capacitors as stacked voltage sources for multilevel voltage generation. The voltage deviation of a dc-link capacitor will occur whenever a phase terminal connects to the balanced neutral points (NPs: terminal joints of dc-link capacitors). On the contrary, if the voltage of a dc-link capacitor deviates from the nominal voltage, the same phase currents can be utilized to balance these NPs. This new technique is being proposed for the first time in the literature. Any voltage disturbance of the dc-link capacitors is balanced using the motor phase currents, irrespective of load power factor and modulation indices. For the balanced NPs, whenever a phase connects to an NP, the other phase terminal tapping positions are varied on the dc link to establish $i_{A}+i_{B}+i_{C}=0$ for that NP. The pole voltage level variation at motor phase terminals is undisturbed by adding extra cascaded H-bridges (CHBs) at each phase leg. The voltages of CHB capacitors are controlled conventionally by inverter pole voltage redundancies. The detailed experimental results for open-loop V/f and closed-loop field-oriented control on an induction motor are presented using a nine-level laboratory prototype. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Cheng-Kai Lin;Crestian A. Agustin;
Pages: 537 - 550 Abstract: Conventional model-based predictive current control suffers from the common drawbacks of high reliance on system model parameters and the use of a single input voltage vector, which result in large pulsating current ripples and prediction errors. In the case of a four-switch three-phase inverter (FSTPI) topology, the implementation of the predictive controller is exacerbated due to the limited number of candidate voltage vectors. This article presents an integrated model-free predictive current control with a hybrid switching mechanism to solve the problem. The proposed method introduces the combined switching mechanism of input voltage vectors with fixed and variable modulations by increasing the number of switching voltage vectors. The four basic voltage vectors generated in the FSTPI create 24 new synthesized voltage vectors through fourfold linear expansions of the space vector plane. The switching durations of input voltage vectors are determined by calculating their optimal duty ratios. As a result, the proposed method improves the prediction accuracy by increasing the iteration calculations of current differences every sampling period. The proposed method, known as the hybrid switching of four-voltage-vector model-free predictive current control, is practically tested via simulation and experimental works to evaluate its effectiveness and performance improvement. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Van Trang Phung;Harith Al-Badrani;Mario Pacas;
Pages: 551 - 560 Abstract: The present work deals with the enhancement of the speed control of an electrical drive under a repetitive mechanical load. In such a system, the load torque changes periodically according to the angular position of the rotor causing speed oscillations. In this article, two methods for mitigating speed oscillations are proposed. One is based on a load torque feedforward control scheme, where the load torque is presented in the form of Fourier series and estimated via the calculation of the Fourier coefficients by taking into account the cyclic characteristics of the driven machine. The other method is based on harmonic speed control that aims to mitigate specific harmonics in the speed error. The design procedure of the harmonic speed controller is presented in detail, providing a full insight into the use of the harmonic controller. Experiments were used to verify and compare the effectiveness of the two proposed methods. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Neha Tak;Sumit K. Chattopadhyay;Chandan Chakraborty;
Pages: 561 - 581 Abstract: Design challenges for grid-connected solar photovoltaic systems related to the power conditioning units are power quality, efficiency, reliability, cost of implementation, etc. This article deals with a single dc-source-based double level-doubling network high-resolution multilevel inverter topology with the appropriate blend of switches to address most of the practical constraints of central inverter application. A two-stage high-resolution multilevel inverter solution is adapted to double the inverter utilization as well as to increase efficiency. Reactive power handling and fault blocking capability of the system are also demonstrated in this work. The converter is extensively simulated using MATLAB/Simulink. Experimental results from the laboratory prototype confirm the usefulness of the proposed concepts. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Shih-Wei Su;Hannes Börngen;Christoph M. Hackl;Ralph Kennel;
Pages: 582 - 593 Abstract: The article proposes a nonlinear current control system of reluctance synchronous machines (RSMs) in combination with analytical flux linkage prototype functions. For highly nonlinear machines, such as RSMs, the magnetic characteristics change significantly throughout the whole operation range due to saturation and cross-coupling effects. Therefore, the current controller tuning must be adapted online to achieve a fast and accurate tracking performance. The proposed current controllers are derived based on the system theoretic concept of the exact input/output (I/O) linearization of the current dynamics. Thus, the nonlinear control system is simplified to an integrator which, in combination of proportional–integral controllers, can be tuned by means of pole placement similar to a phase-locked loop. For I/O linearization and control, the magnetic saturation and cross-coupling effects in the flux linkages and the differential inductances must be considered which is done by the utilization of analytical flux linkage prototype functions instead of lookup tables. The performance of the developed nonlinear current control system is validated by both, simulation and experimental results, for a highly nonlinear $1.5 ,mathrm{k}mathrm{W}$ RSM. The results underpin 1) the very high approximation accuracy and the continuity and differentiability of the flux linkage prototype functions over the whole operation range and 2) the very fast and accurate tracking performance of the nonlinear I/O control system. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Félix Rojas;Cristóbal Jerez;Christoph M. Hackl;Oliver Kalmbach;Javier Pereda;Jonathan Lillo;
Pages: 594 - 614 Abstract: Modular multilevel cascade converters (MMCCs) are considered a promising power electronics topology in industry. Their scalability allows to reach (ultra/very) high voltage levels with low harmonic content and high efficiency and makes MMCCs an ideal solution for high-power applications; such as electrical drives, solid-state transformers, and high-voltage direct-current (HVdc) transmission systems. However, the high levels of thermal, electrical, and mechanical stress on the power electronics devices and the large number of components (e.g., capacitors or semiconductors) make MMCCs prone to faults. Fault detection and diagnosis (FDD) in combination with fault isolation and system reconfiguration techniques, based on cell redundancy, can increase the reliability, availability, and safety of MMCCs, which is crucial for their utilization in critical energy applications. This second part of the article comprehensively surveys: 1) fault tolerance and FDD; e.g., expert system, model-, or hardware and data-based FDD methods, and 2) system reconfiguration strategies (e.g., cold- or hot-redundant) for MMCCs. Finally, the state of the art, challenges, and future research trends and opportunities toward reliable MMCC-based systems are revealed. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Bryan Gutierrez;Seunghoon Baek;Jih-Sheng Lai;
Pages: 615 - 627 Abstract: This article presents a novel space vector pulsewidth modulation (SVPWM) for a three-phase binary-cascaded multilevel inverter (BCMLI). The SVPWM could become impractical in multilevel inverters (MLIs) because of its increasing complexity with a larger number of levels. The gh coordinate system can ease the digital implementation, but to generate the inverter's abc states from the nearest three vectors (NTVs), iterative computations are required every sampling instant. This article proposes a further reduction of computations by directly generating the abc state with minimum common-mode voltage (CMV) from a gh vector. Subsequently, only one vector among the NTVs is required for implementing the proposed SVPWM. The reduced CMV profile within the NTVs further permits the reduction of commutations by clamping one phase during a sampling period. The presented technique exhibits full dc bus utilization capability and can be implemented in the BCMLI and further applied to any M-level MLI. Also, if M is considerably large or if switching losses and electromagnetic interference emissions must be minimized, nearest vector modulation with reduced CMV along with the line-frequency operation of high-voltage cells can be implemented to reduce the switching losses. Experimental results of a BCMLI are presented to verify the effectiveness of the proposed technique. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Félix Rojas;Cristóbal Jerez;Christoph Michael Hackl;Oliver Kalmbach;Javier Pereda;Jonathan Lillo;
Pages: 628 - 649 Abstract: Modular multilevel cascade converters (MMCCs) are considered a promising power electronics topology in industry. Their scalability allows to reach (ultra/very) high voltage levels with low harmonic content and high efficiency and makes MMCCs an ideal solution for high-power applications, such as electrical drives, solid-state transformers, and high-voltage direct-current (HVdc) transmission systems. However, the high levels of thermal, electrical, and mechanical stress on the power electronics devices and the large number of components (e.g., capacitors or semiconductors) make MMCCs prone to faults reducing its reliability. In this first part of the article, a comprehensive overview of the reliability of MMCCs, failure mechanisms, and fault impact analysis in MMCCs, including failure rates and fault modes is presented. Also, a set of tables that collect all information to easily detect and identify faults in MMCCs is presented. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Niloufar Keshmiri;Guvanthi Abeysinghe Mudiyanselage;Sreejith Chakkalakkal;Kyle Kozielski;Giorgio Pietrini;Ali Emadi;
Pages: 650 - 662 Abstract: Three-port converters (TPCs) enable the design of more efficient, power dense,and high-power dc–dc converters. This article investigates the operation of a resonant TPC in electric vehicle applications. Operating conditions of the resonant TPC are presented. The steady-state analysis of the converter with zero-voltage switching consideration is discussed. A controller concept to regulate the resonant TPC is proposed. State-space equations of the resonant TPC are derived, and a nested closed-loop control strategy is implemented. The converter operation is validated in the PLECS simulation environment under step-load and input voltage variation conditions. The resonant TPC can regulate its output voltage under the proposed control strategy and maintain its operation at various operating conditions. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Bingrong Shang;Tianshi Cheng;Tian Liang;Ning Lin;Venkata Dinavahi;
Pages: 663 - 673 Abstract: Power converter design evaluation by means of real-time simulation techniques is prevalent, although it is mostly restricted to simple power semiconductor switch models that exclude device-level physical details. In this work, the nonlinear high-order electrothermal model of the IGBT is developed and then deployed onto the heterogeneous digital hardware for real-time implementation. As the complexity of the NBM of the IGBT poses a significant computational burden on real-time hardware emulation, ML methodology is utilized so that the trained model can reproduce the characteristics of its original counterpart as much as possible and then it is implemented on the ACAP, which composes of the PS, PL, and AIE. The vector multiplication feature of the AIE caters to mathematical operations of the ML-based model particularly well and consequently enables it to be executed in real-time with remarkable speedup over the original model with which matrix inversion is otherwise mandatory. Finally, the validation for real-time device-level results and system-level results of a multiconverter system is provided by SaberRD and MATLAB/Simulink. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Lorenzo Fanari;Eneko Iradier;Iñigo Bilbao;Rufino Cabrera;Jon Montalban;Pablo Angueira;Oscar Seijo;Iñaki Val;
Pages: 674 - 699 Abstract: Industry 4.0 aims to digitize industrial processes entirely, and wireless technologies represent one of the enablers for scalable and flexible communications. However, the current standards and proprietary solutions do not meet the industry's tight requirements in fundamental use cases such as factory automation (FA). One of the key research challenges toward replacing wired fieldbuses with wireless links is the design of techniques that enable real-time and deterministic behavior when transmitting short packets. Forward error correction (FEC) techniques are critical to this objective, and coding/decoding algorithms must comply with reliability and low latency specifications. This article surveys existing FEC techniques for short packet transmissions. Compared to other survey papers in the field, we propose several FEC candidate techniques specifically suitable for FA wireless systems. We explore four of these techniques, also examining hardware architecture proposals. This article proposes a methodology to evaluate their latency and reliability performance. We finally discuss the lessons learned and challenges for future research. PubDate:
2022
Issue No:Vol. 3 (2022)
Authors:
Mohamed Trabelsi;Alamera Nouran Alquennah;Hani Vahedi;
Pages: 711 - 732 Abstract: Nowadays, single-dc-source multilevel inverter (SDCS-MLI) topologies are being considered as more suitable for many power system applications such as renewable energy conversion systems and electrified transportations compared to the multiple-dc-source MLIs. Voltage balancing of the auxiliary capacitors in those configurations is a major matter of concern. Different techniques have been developed to overcome this issue that can be mainly categorized as internal controller-based and external controller-based techniques. In the former techniques, the redundant switching states help balancing the capacitors voltages. On the other hand, the latter techniques involve external regulators to balance the capacitors’ voltages. This article analyzes most of the existing techniques to control and balance the capacitors voltages in SDCS-MLIs, such as pulsewidth modulation, space vector modulation (SVM), hysteresis control, model predictive control, sliding mode, and artificial intelligence based control techniques. Furthermore, a comprehensive comparison is presented to illustrate the advantages/disadvantages of each technique. Finally, some industrial challenges and future works are projected. PubDate:
2022
Issue No:Vol. 3 (2022)
Open Access journal
