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Showing papers in "IEEE Transactions on Industrial Informatics in 2014"


Journal ArticleDOI
TL;DR: This review paper summarizes the current state-of-the-art IoT in industries systematically and identifies research trends and challenges.
Abstract: Internet of Things (IoT) has provided a promising opportunity to build powerful industrial systems and applications by leveraging the growing ubiquity of radio-frequency identification (RFID), and wireless, mobile, and sensor devices. A wide range of industrial IoT applications have been developed and deployed in recent years. In an effort to understand the development of IoT in industries, this paper reviews the current research of IoT, key enabling technologies, major IoT applications in industries, and identifies research trends and challenges. A main contribution of this review paper is that it summarizes the current state-of-the-art IoT in industries systematically.

4,145 citations


Journal ArticleDOI
Fei Tao1, Ying Cheng1, Li Da Xu, Lin Zhang1, Bo Hu Li1 
TL;DR: The applications of the technologies of IoT and CC in manufacturing are investigated and a CC- and IoT-based cloud manufacturing (CMfg) service system and its architecture are proposed, and the relationship among CMfg, IoT, and CC is analyzed.
Abstract: Recently, Internet of Things (IoT) and cloud computing (CC) have been widely studied and applied in many fields, as they can provide a new method for intelligent perception and connection from M2M (including man-to-man, man-to-machine, and machine-to-machine), and on-demand use and efficient sharing of resources, respectively. In order to realize the full sharing, free circulation, on-demand use, and optimal allocation of various manufacturing resources and capabilities, the applications of the technologies of IoT and CC in manufacturing are investigated in this paper first. Then, a CC- and IoT-based cloud manufacturing (CMfg) service system (i.e., CCIoT-CMfg) and its architecture are proposed, and the relationship among CMfg, IoT, and CC is analyzed. The technology system for realizing the CCIoT-CMfg is established. Finally, the advantages, challenges, and future works for the application and implementation of CCIoT-CMfg are discussed.

617 citations


Journal ArticleDOI
TL;DR: The evolution of manufacturing system paradigms is discussed to identify the requirements of decision support systems in dynamic and distributed environments; recent advances in IT are overviewed and associated with next-generation manufacturing paradigm; and the relation of IT infrastructure and ESs is explored to identified the technological gaps in adopting IoT as an IT infrastructure of ESs.
Abstract: Design and operation of a manufacturing enterprise involve numerous types of decision-making at various levels and domains. A complex system has a large number of design variables and decision-making requires real-time data collected from machines, processes, and business environments. Enterprise systems (ESs) are used to support data acquisition, communication, and all decision-making activities. Therefore, information technology (IT) infrastructure for data acquisition and sharing affects the performance of an ES greatly. Our objective is to investigate the impact of emerging Internet of Things (IoT) on ESs in modern manufacturing. To achieve this objective, the evolution of manufacturing system paradigms is discussed to identify the requirements of decision support systems in dynamic and distributed environments; recent advances in IT are overviewed and associated with next-generation manufacturing paradigms; and the relation of IT infrastructure and ESs is explored to identify the technological gaps in adopting IoT as an IT infrastructure of ESs. The future research directions in this area are discussed.

595 citations


Journal ArticleDOI
TL;DR: The proposed iHome Health-IoT platform seamlessly fuses IoT devices with in-home healthcare services for an improved user experience and service efficiency.
Abstract: In-home healthcare services based on the Internet-of-Things (IoT) have great business potential; however, a comprehensive platform is still missing. In this paper, an intelligent home-based platform, the iHome Health-IoT, is proposed and implemented. In particular, the platform involves an open-platform-based intelligent medicine box (iMedBox) with enhanced connectivity and interchangeability for the integration of devices and services; intelligent pharmaceutical packaging (iMedPack) with communication capability enabled by passive radio-frequency identification (RFID) and actuation capability enabled by functional materials; and a flexible and wearable bio-medical sensor device (Bio-Patch) enabled by the state-of-the-art inkjet printing technology and system-on-chip. The proposed platform seamlessly fuses IoT devices (e.g., wearable sensors and intelligent medicine packages) with in-home healthcare services (e.g., telemedicine) for an improved user experience and service efficiency. The feasibility of the implemented iHome Health-IoT platform has been proven in field trials.

559 citations


Journal ArticleDOI
TL;DR: The result shows that the resource-based IoT data accessing method is effective in a distributed heterogeneous data environment for supporting data accessing timely and ubiquitously in a cloud and mobile computing platform.
Abstract: The rapid development of Internet of things (IoT) technology makes it possible for connecting various smart objects together through the Internet and providing more data interoperability methods for application purpose. Recent research shows more potential applications of IoT in information intensive industrial sectors such as healthcare services. However, the diversity of the objects in IoT causes the heterogeneity problem of the data format in IoT platform. Meanwhile, the use of IoT technology in applications has spurred the increase of real-time data, which makes the information storage and accessing more difficult and challenging. In this research, first a semantic data model is proposed to store and interpret IoT data. Then a resource-based data accessing method (UDA-IoT) is designed to acquire and process IoT data ubiquitously to improve the accessibility to IoT data resources. Finally, we present an IoT-based system for emergency medical services to demonstrate how to collect, integrate, and interoperate IoT data flexibly in order to provide support to emergency medical services. The result shows that the resource-based IoT data accessing method is effective in a distributed heterogeneous data environment for supporting data accessing timely and ubiquitously in a cloud and mobile computing platform.

546 citations


Journal ArticleDOI
TL;DR: The idea is to investigate the non-negative update process depending on each involved feature rather than on the whole feature matrices, and propose the regularized single-element-based NMF (RSNMF) model, which is especially suitable for solving CF problems subject to the constraint of non-negativity.
Abstract: Matrix-factorization (MF)-based approaches prove to be highly accurate and scalable in addressing collaborative filtering (CF) problems. During the MF process, the non-negativity, which ensures good representativeness of the learnt model, is critically important. However, current non-negative MF (NMF) models are mostly designed for problems in computer vision, while CF problems differ from them due to their extreme sparsity of the target rating-matrix. Currently available NMF-based CF models are based on matrix manipulation and lack practicability for industrial use. In this work, we focus on developing an NMF-based CF model with a single-element-based approach. The idea is to investigate the non-negative update process depending on each involved feature rather than on the whole feature matrices. With the non-negative single-element-based update rules, we subsequently integrate the Tikhonov regularizing terms, and propose the regularized single-element-based NMF (RSNMF) model. RSNMF is especially suitable for solving CF problems subject to the constraint of non-negativity. The experiments on large industrial datasets show high accuracy and low-computational complexity achieved by RSNMF.

533 citations


Journal ArticleDOI
TL;DR: The applications of IoT technologies in CMfg has been investigated and the classification of manufacturing resources and services, as well as their relationships, are presented.
Abstract: Recently, cloud manufacturing (CMfg) as a new service-oriented manufacturing mode has been paid wide attention around the world. However, one of the key technologies for implementing CMfg is how to realize manufacturing resource intelligent perception and access. In order to achieve intelligent perception and access of various manufacturing resources, the applications of IoT technologies in CMfg has been investigated in this paper. The classification of manufacturing resources and services, as well as their relationships, are presented. A five-layered structure (i.e., resource layer, perception layer, network layer, service layer, and application layer) resource intelligent perception and access system based on IoT is designed and presented. The key technologies for intelligent perception and access of various resources (i.e., hard manufacturing resources, computational resources, and intellectual resources) in CMfg are described. A prototype application system is developed to valid the proposed method.

526 citations


Journal ArticleDOI
TL;DR: A novel multilayered vehicular data cloud platform is presented by using cloud computing and IoT technologies to resolve the challenges caused by the increasing transportation issues.
Abstract: The advances in cloud computing and internet of things (IoT) have provided a promising opportunity to resolve the challenges caused by the increasing transportation issues. We present a novel multilayered vehicular data cloud platform by using cloud computing and IoT technologies. Two innovative vehicular data cloud services, an intelligent parking cloud service and a vehicular data mining cloud service, for vehicle warranty analysis in the IoT environment are also presented. Two modified data mining models for the vehicular data mining cloud service, a Naive Bayes model and a Logistic Regression model, are presented in detail. Challenges and directions for future work are also provided.

523 citations


Journal ArticleDOI
TL;DR: The study shows that the research work is greatly benefited from such an IIS, not only in data collection supported by IoT, but also in Web services and applications based on cloud computing and e-Science platforms, and the effectiveness of monitoring processes and decision-making can be obviously improved.
Abstract: Climate change and environmental monitoring and management have received much attention recently, and an integrated information system (IIS) is considered highly valuable. This paper introduces a novel IIS that combines Internet of Things (IoT), Cloud Computing, Geoinformatics [remote sensing (RS), geographical information system (GIS), and global positioning system (GPS)], and e-Science for environmental monitoring and management, with a case study on regional climate change and its ecological effects. Multi-sensors and Web services were used to collect data and other information for the perception layer; both public networks and private networks were used to access and transport mass data and other information in the network layer. The key technologies and tools include real-time operational database (RODB); extraction-transformation-loading (ETL); on-line analytical processing (OLAP) and relational OLAP (ROLAP); naming, addressing, and profile server (NAPS); application gateway (AG); application software for different platforms and tasks (APPs); IoT application infrastructure (IoT-AI); GIS and e-Science platforms; and representational state transfer/Java database connectivity (RESTful/JDBC). Application Program Interfaces (APIs) were implemented in the middleware layer of the IIS. The application layer provides the functions of storing, organizing, processing, and sharing of data and other information, as well as the functions of applications in environmental monitoring and management. The results from the case study show that there is a visible increasing trend of the air temperature in Xinjiang over the last 50 years (1962-2011) and an apparent increasing trend of the precipitation since the early 1980s. Furthermore, from the correlation between ecological indicators [gross primary production (GPP), net primary production (NPP), and leaf area index (LAI)] and meteorological elements (air temperature and precipitation), water resource availability is the decisive factor with regard to the terrestrial ecosystem in the area. The study shows that the research work is greatly benefited from such an IIS, not only in data collection supported by IoT, but also in Web services and applications based on cloud computing and e-Science platforms, and the effectiveness of monitoring processes and decision-making can be obviously improved. This paper provides a prototype IIS for environmental monitoring and management, and it also provides a new paradigm for the future research and practice; especially in the era of big data and IoT.

443 citations


Journal ArticleDOI
TL;DR: Experimental results show that FAF-EBRM outperforms LEACH and EEUC, which balances the energy consumption, prolongs the function lifetime and guarantees high QoS of WSN.
Abstract: As an important part of industrial application (IA), the wireless sensor network (WSN) has been an active research area over the past few years. Due to the limited energy and communication ability of sensor nodes, it seems especially important to design a routing protocol for WSNs so that sensing data can be transmitted to the receiver effectively. An energy-balanced routing method based on forward-aware factor (FAF-EBRM) is proposed in this paper. In FAF-EBRM, the next-hop node is selected according to the awareness of link weight and forward energy density. Furthermore, a spontaneous reconstruction mechanism for local topology is designed additionally. In the experiments, FAF-EBRM is compared with LEACH and EEUC, experimental results show that FAF-EBRM outperforms LEACH and EEUC, which balances the energy consumption, prolongs the function lifetime and guarantees high QoS of WSN.

436 citations


Journal ArticleDOI
Yuanjie Fan1, Yuehong Yin1, Li Da Xu, Yan Zeng1, Fan Wu1 
TL;DR: This paper presents an ontology-based automating design methodology (ADM) for smart rehabilitation systems in IoT and preliminary experiments and clinical trials demonstrate valuable information on the feasibility, rapidity, and effectiveness of the proposed methodology.
Abstract: Internet of Things (IoT) makes all objects become interconnected and smart, which has been recognized as the next technological revolution. As its typical case, IoT-based smart rehabilitation systems are becoming a better way to mitigate problems associated with aging populations and shortage of health professionals. Although it has come into reality, critical problems still exist in automating design and reconfiguration of such a system enabling it to respond to the patient's requirements rapidly. This paper presents an ontology-based automating design methodology (ADM) for smart rehabilitation systems in IoT. Ontology aids computers in further understanding the symptoms and medical resources, which helps to create a rehabilitation strategy and reconfigure medical resources according to patients' specific requirements quickly and automatically. Meanwhile, IoT provides an effective platform to interconnect all the resources and provides immediate information interaction. Preliminary experiments and clinical trials demonstrate valuable information on the feasibility, rapidity, and effectiveness of the proposed methodology.

Journal ArticleDOI
TL;DR: With equivalent transformation and specialized sector distribution method, the computation load of FCS-MPC is greatly reduced while the control performance is not affected and the proposed method can be used in various circuit topologies and cases with multiple constraints.
Abstract: Finite-control-set model-predictive control (FCS-MPC) requires a large amount of calculation, which is an obstacle for its application. However, compared with the classical linear control algorithm, FCS-MPC requires a shorter control loop cycle time to reach the same control performance. To resolve this contradiction, this paper presents an effective method to simplify the conventional FCS-MPC. With equivalent transformation and specialized sector distribution method, the computation load of FCS-MPC is greatly reduced while the control performance is not affected. The proposed method can be used in various circuit topologies and cases with multiple constraints. Experiments on two-level converter and three-level NPC converter verify the good performance and application value of the proposed method.

Journal ArticleDOI
TL;DR: A multiobjective optimization problem is formulated to minimize the overall ESS size, while maximizing the battery cycle life according to the assigned penalty functions, by a sample-based global search oriented DIviding RECTangles (DIRECT) algorithm.
Abstract: Electric vehicle (EV) batteries tend to have accelerated degradation due to high peak power and harsh charging/ discharging cycles during acceleration and deceleration periods, particularly in Urban driving conditions. Oversized energy storage system (ESS) meets the high power demand; however, in tradeoff with increased ESS size, volume, and cost. In order to reduce overall ESS size and extend battery cycle life, battery/ultracapacitor (UC) hybrid ESS (HESS) has been considered as a solution in which UCs act as a power buffer to charging/discharging peak power. In this paper, a multiobjective optimization problem is formulated to minimize the overall ESS size, while maximizing the battery cycle life according to the assigned penalty functions. An integrated framework for HESS sizing and battery cycle life optimization applied in a midsize EV, using an Autonomie simulation model, is described and illustrated in this paper. This multidimensional optimization is realized by a sample-based global search oriented DIviding RECTangles (DIRECT) algorithm. The optimization results under Urban Dynamometer Driving Schedule (UDDS) are compared with the battery-only ESS results, which demonstrate significant battery cycle life extension of 76% achieved by the optimized HESS with 72 UC cells.

Journal ArticleDOI
TL;DR: A data storage framework not only enabling efficient storing of massive IoT data, but also integrating both structured and unstructured data is proposed, able to combine and extend multiple databases and Hadoop to store and manage diverse types of data collected by sensors and RFID readers.
Abstract: The Internet of Things (IoT) has provided a promising opportunity to build powerful industrial systems and applications by leveraging the growing ubiquity of Radio Frequency IDentification (RFID) and wireless sensors devices. Benefiting from RFID and sensor network technology, common physical objects can be connected, and are able to be monitored and managed by a single system. Such a network brings a series of challenges for data storage and processing in a cloud platform. IoT data can be generated quite rapidly, the volume of data can be huge and the types of data can be various. In order to address these potential problems, this paper proposes a data storage framework not only enabling efficient storing of massive IoT data, but also integrating both structured and unstructured data. This data storage framework is able to combine and extend multiple databases and Hadoop to store and manage diverse types of data collected by sensors and RFID readers. In addition, some components are developed to extend the Hadoop to realize a distributed file repository, which is able to process massive unstructured files efficiently. A prototype system based on the proposed framework is also developed to illustrate the framework's effectiveness.

Journal ArticleDOI
TL;DR: A new method is proposed to design a reconfigurable smart sensor interface for industrial WSN in IoT environment, in which complex programmable logic device (CPLD) is adopted as the core controller and the standard of IEEE1451.2 intelligent sensor interface specification is adopted.
Abstract: A sensor interface device is essential for sensor data collection of industrial wireless sensor networks (WSN) in IoT environments. However, the current connect number, sampling rate, and signal types of sensors are generally restricted by the device. Meanwhile, in the Internet of Things (IoT) environment, each sensor connected to the device is required to write complicated and cumbersome data collection program code. In this paper, to solve these problems, a new method is proposed to design a reconfigurable smart sensor interface for industrial WSN in IoT environment, in which complex programmable logic device (CPLD) is adopted as the core controller. Thus, it can read data in parallel and in real time with high speed on multiple different sensor data. The standard of IEEE1451.2 intelligent sensor interface specification is adopted for this design. It comprehensively stipulates the smart sensor hardware and software design framework and relevant interface protocol to realize the intelligent acquisition for common sensors. A new solution is provided for the traditional sensor data acquisitions. The device is combined with the newest CPLD programmable technology and the standard of IEEE1451.2 intelligent sensor specification. Performance of the proposed system is verified and good effects are achieved in practical application of IoT to water environment monitoring.

Journal ArticleDOI
TL;DR: Results show that reactive compensation from PV inverters alone is sufficient to maintain acceptable voltage profile in an urban scenario, whereas coordinated PV and BES support is required for the rural scenario (high-resistance feeder).
Abstract: Increasing penetration of photovoltaic (PV), as well as increasing peak load demand, has resulted in poor voltage profile for some residential distribution networks. This paper proposes coordinated use of PV and battery energy storage (BES) to address voltage rise and/or dip problems. The reactive capability of PV inverter combined with droop-based BES system is evaluated for rural and urban scenarios (having different \mbi R/X ratios). Results show that reactive compensation from PV inverters alone is sufficient to maintain acceptable voltage profile in an urban scenario (low-resistance feeder), whereas coordinated PV and BES support is required for the rural scenario (high-resistance feeder). Constant, as well as variable, droop-based BES schemes are analyzed. The required BES sizing and associated cost to maintain the acceptable voltage profile under both schemes are presented. Uncertainties in PV generation and load are considered, with probabilistic estimation of PV generation and randomness in load modeled to characterize the effective utilization of BES. Actual PV generation data and distribution system network data are used to verify the efficacy of the proposed method.

Journal ArticleDOI
TL;DR: The architectures and technologies for integrating distributed enterprise applications are examined, their strengths and weaknesses are illustrated, and research trends and opportunities are identified in this increasingly important area.
Abstract: Many industrial enterprises acquire disparate systems and applications over the years. The need to integrate these different systems and applications is often prominent for satisfying business requirements and needs. In an effort to help researchers in industrial informatics understand the state-of-the-art of the enterprise application integration, we examined the architectures and technologies for integrating distributed enterprise applications, illustrated their strengths and weaknesses, and identified research trends and opportunities in this increasingly important area.

Journal ArticleDOI
TL;DR: Results show that constructing a control system to restrict fuel cell's and batteries' current slope and maintaining dc bus voltage in accordance with the reference values using MPC was feasible and effectively done.
Abstract: Well known as an efficient and eco-friendly power source, fuel cell, unfortunately, offers slow dynamics. When attached as primary energy source in a vehicle, fuel cell would not be able to respond to abrupt load variations. Supplementing battery and/or supercapacitor to the system will provide a solution to this shortcoming. On the other hand, a current regulation that is vital for lengthening time span of the energy storage system is needed. This can be accomplished by keeping fuel cell's and batteries' current slope in reference to certain values, as well as attaining a stable dc output voltage. For that purpose, a feedback control system for regulating the hybrid of fuel cell, batteries, and supercapacitor was constructed for this study. Output voltage of the studied hybrid power sources (HPS) was administered by assembling three dc-dc converters comprising two bidirectional converters and one boost converter. Current/voltage output of fuel cell was regulated by boost converter, whereas the bidirectional converters regulated battery and supercapacitor. Reference current for each converter was produced using Model Predictive Control (MPC) and subsequently tracked using hysteresis control. These functions were done on a controller board of a dSPACE DS1104. Subsequently, on a test bench made up from 6 V, 4.5 Ah battery and 7.5 V, 120 F supercapacitor together with a fuel cell of 50 W, 10 A, experiment was conducted. Results show that constructing a control system to restrict fuel cell's and batteries' current slope and maintaining dc bus voltage in accordance with the reference values using MPC was feasible and effectively done.

Journal ArticleDOI
TL;DR: A system-wide demand response management model to coordinate demand response provided by residential customers and flatten the total load profile that is subject to minimum individual cost of customers is presented.
Abstract: Demand response enabled by time-varying prices can propel the power industry toward a greater efficiency. However, a noncoordinated response of customers may lead to severe peak rebounds at periods with lower prices. In this regard, a coordinated demand response scheme can mitigate concerns about the peak rebounds. This paper presents a system-wide demand response management model to coordinate demand response provided by residential customers. The objective of the model is to flatten the total load profile that is subject to minimum individual cost of customers. The model is first formulated as a bi-level optimization problem. It is then casted into equivalent single-level problems, which are solved via an iterative distributed algorithm. Home load management (HLM) modules embedded in customers' smart meters are autonomous agents associated with the algorithm. In the algorithm, at first, HLM modules, in response to prices announced by the utility, optimize the daily operation of household appliances and send back the scheduled load profiles. Then, the total load profile is calculated and released by the utility. Thereafter, the HLM modules asynchronously update their schedule such that, given their least energy expenses, the most evenly distributed total load profile is achieved. The mutual interaction between the utility and HLM modules is continued to the point in which no further improvement is obtained. Convergence and optimality of the algorithm are proved.

Journal ArticleDOI
TL;DR: A new continuous dynamic sliding-mode control (CDSMC) method is proposed for high-order mismatched disturbance attenuation in motion control systems using a high- order sliding- mode differentiator and results show that the proposed method exhibits promising control performance in the presence of high-orders matched and mismatched disturbances.
Abstract: A new continuous dynamic sliding-mode control (CDSMC) method is proposed for high-order mismatched disturbance attenuation in motion control systems using a high-order sliding-mode differentiator. First, a new dynamic sliding surface is developed by incorporating the information of the estimates of disturbances and their high-order derivatives. A CDSMC law is then designed for a general motion control system with both high-order matched and mismatched disturbances, which can attenuate the effects of disturbances from the system output. The proposed control method is finally applied for the airgap control of a MAGnetic LEViation (MAGLEV) suspension vehicle. Simulation results show that the proposed method exhibits promising control performance in the presence of high-order matched and mismatched disturbances.

Journal ArticleDOI
TL;DR: The proposed QoS-aware scheduling for service-oriented IoT architecture is able to optimize the scheduling performance of IoT network and minimize the resource costs.
Abstract: The Internet of Things (IoT) contains a large number of different devices and heterogeneous networks, which make it difficult to satisfy different quality of service (QoS) requirements and achieve rapid services composition and deployment In addition, some services in service-oriented IoT are required to be reconfigurable and composable for QoS-aware services This paper proposed a three-layer QoS scheduling model for service-oriented IoT At application layer, the QoS schedule scheme explores optimal QoS-aware services composition by using the knowledge of each component service At network layer, the model aims at dealing with scheduling of heterogeneous networks environment; at sensing layer, it deals with the information acquisition and resource allocation scheduling for different services The proposed QoS-aware scheduling for service-oriented IoT architecture is able to optimize the scheduling performance of IoT network and minimize the resource costs

Journal ArticleDOI
TL;DR: A straightforward procedure is developed to tune the lead-lag network with the help of software tools and the rationale of this procedure, based on the capacitor current feedback, is elucidated.
Abstract: Three-phase active rectifiers guarantee sinusoidal input currents and unity power factor at the price of a high switching frequency ripple. To adopt an LCL-filter, instead of an L-filter, allows using reduced values for the inductances and so preserving dynamics. However, stability problems can arise in the current control loop if the present resonance is not properly damped. Passive damping simply adds resistors in series with the LCL-filter capacitors. This simplicity is at the expense of increased losses and encumbrances. Active damping modifies the control algorithm to attain stability without using dissipative elements but, sometimes, needing additional sensors. This solution has been addressed in many publications. The lead-lag network method is one of the first reported procedures and continues being in use. However, neither there is a direct tuning procedure (without trial and error) nor its rationale has been explained. Thus, in this paper a straightforward procedure is developed to tune the lead-lag network with the help of software tools. The rationale of this procedure, based on the capacitor current feedback, is elucidated. Stability is studied by means of the root locus analysis in z-plane. Selecting the lead-lag network for the maximum damping in the closed-loop poles uses a simple optimization algorithm. The robustness against the grid inductance variation is also analyzed. Simulations and experiments confirm the validity of the proposed design flow.

Journal ArticleDOI
TL;DR: A delay time control method that is capable of adjusting delay time is further proposed to improve system stability and verified the analysis result and proposed method.
Abstract: Delay is inevitable in digital-controlled system and the delay will change system phase-frequency characteristic, thus affecting system stability. The system stability of inductor-capacitor-inductor (LCL)-type grid-connected inverter with single-loop control based on inverter-side current and single-loop control based on grid-side current is analyzed both in continuous and discrete domains. The influence of delay time on system stability is systematically studied. A delay time control method that is capable of adjusting delay time is further proposed to improve system stability. The proposed delay time control method is applied in the experiment, making an unstable system to be stable, and verifies the analysis result and proposed method.

Journal ArticleDOI
TL;DR: IoT and cloud computing are proposed to help a conventional assembly modeling system evolve into an advanced system, which is capable to deal with complexity and changes automatically.
Abstract: After the technologies of integrated circuits, personal computers, and the Internet, Internet of Things (IoT) is the latest information technology (IT) that is radically changing business paradigms. However, IoT's influence in the manufacturing sector has yet been fully explored. On the other hand, existing computer-aided software tools are experiencing a bottleneck in dealing with complexity, dynamics, and uncertainties in their applications of modern enterprises. It is argued that the adoption of IoT and cloud computing in enterprise systems (ESs) would overcome the bottleneck. In this paper, the challenges in generating assembly plans of complex products are discussed. IoT and cloud computing are proposed to help a conventional assembly modeling system evolve into an advanced system, which is capable to deal with complexity and changes automatically. To achieve this goal, an assembly modeling system is automated, and the proposed system includes the following innovations: 1) the modularized architecture to make the system robust, reliable, flexible, and expandable; 2) the integrated object-oriented templates to facilitate interfaces and reuses of system components; and 3) the automated algorithms to retrieve relational assembly matrices for assembly planning. Assembly modeling for aircraft engines is used as examples to illustrate the system effectiveness.

Journal ArticleDOI
TL;DR: A distributed two-layer control structure for ac microgrids that regulates the active and reactive powers of CCVSIs and is verified on a microgrid test system and IEEE 34 test feeder.
Abstract: This paper proposes a distributed two-layer control structure for ac microgrids. Inverter-based distributed generators (DGs) can operate either as voltage-controlled voltage source inverters (VCVSI) or current-controlled voltage source inverters (CCVSI). VCVSIs provide the voltage and frequency support, whereas CCVSIs regulate the generated active and reactive powers. The proposed control structure has two main layers. The first layer deals with the voltage and frequency control of VCVSIs. The second layer regulates the active and reactive powers of CCVSIs. These controllers are implemented through two communication networks with one-way communication links and are fully distributed; each DG only requires its own information and the information of its neighbors on the communication network graph. The proposed control framework is verified on a microgrid test system and IEEE 34 test feeder.

Journal ArticleDOI
TL;DR: This paper presents a secure power-usage data aggregation scheme for smart grid, which is the first scheme against internal attackers, and it provides secure batch verification.
Abstract: According to related research, energy consumption can be effectively reduced by using energy management information of smart grids. In smart grid architecture, electricity suppliers can monitor, predicate, and control energy generation/consumption in real time. Users can know the current price of electrical energy and obtain energy management information from smart meters. It helps users reduce home's energy use. However, electricity consumptions of users may divulge the privacy information of users. Therefore, privacy of users and communication security of the smart grid become crucial security issues. This paper presents a secure power-usage data aggregation scheme for smart grid. Electricity suppliers can learn about the current power usage of each neighborhood to arrange energy supply and distribution without knowing the individual electricity consumption of each user. This is the first scheme against internal attackers, and it provides secure batch verification. Additionally, the security of the proposed scheme is demonstrated by formal proofs.

Journal ArticleDOI
TL;DR: This paper describes and evaluates an adaptive neuro-fuzzy inference system (ANFIS)-based energy management system (EMS) of a grid-connected hybrid system and compares with a classical EMS composed of state-based supervisory control system based on states and inverter control systembased on PI controllers.
Abstract: This paper describes and evaluates an adaptive neuro-fuzzy inference system (ANFIS)-based energy management system (EMS) of a grid-connected hybrid system. It presents a wind turbine (WT) and photovoltaic (PV) solar panels as primary energy sources, and an energy storage system (ESS) based on hydrogen (fuel cell -FC-, hydrogen tank and electrolyzer) and battery. All of the energy sources use dc/dc power converters in order to connect them to a central DC bus. An ANFIS-based supervisory control system determines the power that must be generated by/stored in the hydrogen and battery, taking into account the power demanded by the grid, the available power, the hydrogen tank level and the state-of-charge (SOC) of the battery. Furthermore, an ANFIS-based control is applied to the three-phase inverter, which connects the hybrid system to grid. Otherwise, this new EMS is compared with a classical EMS composed of state-based supervisory control system based on states and inverter control system based on PI controllers. Dynamic simulations demonstrate the right performance of the ANFIS-based EMS for the hybrid system under study and the better performance with respect to the classical EMS.

Journal ArticleDOI
TL;DR: A novel cascaded boost-buck dc-dc converter is designed to provide the optimal impedance matching in WPT system for various loads including resistive load, ultracapacitors, and batteries.
Abstract: Wireless power transfer (WPT) has attracted an ever increasing interest from both industry and academics over the past few years. Its applications vary from small power devices such as mobile phones and tablets to high power electric vehicles and from small transfer distance of centimeters to large distance of tens of centimeters. In order to achieve a high-efficiency WPT system, each circuit should function at a high efficiency along with the proper impedance matching techniques to minimize the power reflection due to the impedance mismatch. This paper proposes an analysis on the system efficiency to determine the optimal impedance requirement for coils, rectifier, and dc-dc converter. A novel cascaded boost-buck dc-dc converter is designed to provide the optimal impedance matching in WPT system for various loads including resistive load, ultracapacitors, and batteries. The proposed 13.56-MHz WPT system can achieve a total system efficiency over 70% in experiment.

Journal ArticleDOI
TL;DR: A design procedure with remarkable results under severe grid inductance variation is proposed, which considers active damping using lead-lag network and capacitor current feedback and selects the proper ratios between the switching and resonance frequency, the grid and converter inductance, and the filter capacitance and total inductance.
Abstract: Grid-connected converters employ LCL-filters, instead of simple inductors, because they allow lower inductances while reducing cost and size. Active damping, without dissipative elements, is preferred to passive damping for solving the associated stability problems. However, large variations in the grid inductance may compromise system stability, and this problem is more severe for parallel converters. This situation, typical of rural areas with solar and wind resources, calls for robust LCL-filter design. This paper proposes a design procedure with remarkable results under severe grid inductance variation. The procedure considers active damping using lead-lag network and capacitor current feedback. Passive damping is also discussed. The design flow, with little iteration and no complex algorithms, selects the proper ratios between the switching and resonance frequency, the grid and converter inductance, and the filter capacitance and total inductance. An estimation for the grid current total harmonic distortion (THD) is also proposed. Simulation and experiments validate the proposals.

Journal ArticleDOI
TL;DR: This paper evaluates a hybrid powertrain based on fuel cell, battery, and supercapacitor for the “Urbos 3” tramway, which currently operates powered by SC in the city of Zaragoza, Spain.
Abstract: This paper evaluates a hybrid powertrain based on fuel cell (FC), battery, and supercapacitor (SC) for the “Urbos 3” tramway, which currently operates powered by SC in the city of Zaragoza, Spain. Due to the dynamic limitations of the main energy source, a proton-exchange-membrane (PEM) FC, other energy secondary sources (ESSs), battery and SC, are needed to supply the vehicle power demand. Moreover, these energy sources allow the energy recovery during regenerative braking. The different sources are connected to a dc bus through dc-dc converters which adapt their variable voltages to the bus voltage and allow the control of energy flow between the sources and the load. The components of the hybrid tramway have been modeled in Matlab/Simulink and are based on commercially available devices. The energy management system used in this work to achieve a proper operation of the energy sources of the hybrid powertrain is based on predictive control. Simulations for the real cycle of the tramway show the suitability of the proposed powertrain and control strategy.