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Electronics, Volume 7, Issue 7 (July 2018)

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Cover Story (view full-size image) Water shortage has affected a plant growth and development negatively. The transpiration through [...] Read more.
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Open AccessArticle An Adaptive Power Harvester with Active Load Modulation for Highly Efficient Short/Long Range RF WPT Applications
Electronics 2018, 7(7), 125; https://doi.org/10.3390/electronics7070125
Received: 31 May 2018 / Revised: 12 July 2018 / Accepted: 17 July 2018 / Published: 23 July 2018
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Abstract
After demonstrating, in previous works, the proof of concept of adaptive rectifiers with active load modulation to operate simultaneously for short/long range RF Wireless Power Transfer (WPT) while maintaining a high Power Conversion Efficiency (PCE), the authors introduced in this paper a power
[...] Read more.
After demonstrating, in previous works, the proof of concept of adaptive rectifiers with active load modulation to operate simultaneously for short/long range RF Wireless Power Transfer (WPT) while maintaining a high Power Conversion Efficiency (PCE), the authors introduced in this paper a power link budget of the proposed adaptive rectifier with a compromise between distance and efficiency. Then, to further exhibit its capabilities and enhance its performance, this paper first introduced a discussion about the parameters preventing the rectifier from operating over a wide range of input powers was performed. Furthermore, active load modulation was implemented and its co-simulation results presented. Finally, an adaptive rectifier was fabricated and its results successfully compared to measured data. It exhibits 40% of PCE over a wide dynamic input range of incident RF power levels from −6 to 25 dBm at the 900 MHz in the Industrial Scientific Medical band (ISM band), with a maximum PCE of 66% for an input power of 15 dBm. The proposed devices are therefore suitable for WPT applications to harvest energy from a controlled source. Full article
(This article belongs to the Special Issue RFID, WPT and Energy Harvesting)
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Open AccessArticle Creation and Detection of Hardware Trojans Using Non-Invasive Off-The-Shelf Technologies
Electronics 2018, 7(7), 124; https://doi.org/10.3390/electronics7070124
Received: 6 June 2018 / Revised: 17 July 2018 / Accepted: 20 July 2018 / Published: 22 July 2018
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Abstract
As a result of the globalisation of the semiconductor design and fabrication processes, integrated circuits are becoming increasingly vulnerable to malicious attacks. The most concerning threats are hardware trojans. A hardware trojan is a malicious inclusion or alteration to the existing design of
[...] Read more.
As a result of the globalisation of the semiconductor design and fabrication processes, integrated circuits are becoming increasingly vulnerable to malicious attacks. The most concerning threats are hardware trojans. A hardware trojan is a malicious inclusion or alteration to the existing design of an integrated circuit, with the possible effects ranging from leakage of sensitive information to the complete destruction of the integrated circuit itself. While the majority of existing detection schemes focus on test-time, they all require expensive methodologies to detect hardware trojans. Off-the-shelf approaches have often been overlooked due to limited hardware resources and detection accuracy. With the advances in technologies and the democratisation of open-source hardware, however, these tools enable the detection of hardware trojans at reduced costs during or after production. In this manuscript, a hardware trojan is created and emulated on a consumer FPGA board. The experiments to detect the trojan in a dormant and active state are made using off-the-shelf technologies taking advantage of different techniques such as Power Analysis Reports, Side Channel Analysis and Thermal Measurements. Furthermore, multiple attempts to detect the trojan are demonstrated and benchmarked. Our simulations result in a state-of-the-art methodology to accurately detect the trojan in both dormant and active states using off-the-shelf hardware. Full article
(This article belongs to the Special Issue Open-Source Electronics Platforms: Development and Applications)
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Open AccessArticle Accurate Synchronization of Digital and Analog Chaotic Systems by Parameters Re-Identification
Electronics 2018, 7(7), 123; https://doi.org/10.3390/electronics7070123
Received: 30 June 2018 / Revised: 14 July 2018 / Accepted: 18 July 2018 / Published: 20 July 2018
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Abstract
The verification of the digital models of chaotic systems and processes is a valuable problem in many practical applications, such as nonlinear control and communications. In our study, we propose a hybrid technique for chaotic systems’ identification, based on the chaotic synchronization of
[...] Read more.
The verification of the digital models of chaotic systems and processes is a valuable problem in many practical applications, such as nonlinear control and communications. In our study, we propose a hybrid technique for chaotic systems’ identification, based on the chaotic synchronization of digital and analog counterparts and a numerical optimization method used for the fine tuning of parameters. An analog circuit implementing the Rössler oscillator with digitally controlled parameters was chosen as an identification object, and the FPGA model was used as a digital counterpart for coupling and parameter retrieval. The synchronization between analog and digital chaotic models can be used to estimate the quality of an identification procedure. The results of this study clarify the practical bounds of digital and analog systems’ equivalence. They also contribute to the problem of designing technical systems possessing advantages of both analog and digital chaotic generators (e.g., a high accuracy and protection from quasi-chaotic oscillation modes). Full article
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Open AccessArticle Implementation of Deep Learning-Based Automatic Modulation Classifier on FPGA SDR Platform
Electronics 2018, 7(7), 122; https://doi.org/10.3390/electronics7070122
Received: 3 June 2018 / Revised: 13 July 2018 / Accepted: 16 July 2018 / Published: 19 July 2018
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Abstract
Intelligent radios collect information by sensing signals within the radio spectrum, and the automatic modulation recognition (AMR) of signals is one of their most challenging tasks. Although the result of a modulation classification based on a deep neural network is better, the training
[...] Read more.
Intelligent radios collect information by sensing signals within the radio spectrum, and the automatic modulation recognition (AMR) of signals is one of their most challenging tasks. Although the result of a modulation classification based on a deep neural network is better, the training of the neural network requires complicated calculations and expensive hardware. Therefore, in this paper, we propose a master–slave AMR architecture using the reconfigurability of field-programmable gate arrays (FPGAs). First, we discuss the method of building AMR, by using a stack convolution autoencoder (CAE), and analyze the principles of training and classification. Then, on the basis of the radiofrequency network-on-chip architecture, the constraint conditions of AMR in FPGA are proposed from the aspects of computing optimization and memory access optimization. The experimental results not only demonstrated that AMR-based CAEs worked correctly, but also showed that AMR based on neural networks could be implemented on FPGAs, with the potential for dynamic spectrum allocation and cognitive radio systems. Full article
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Open AccessArticle Development of Novel and Ultra-High-Performance Supercapacitor Based on a Four Layered Unique Structure
Electronics 2018, 7(7), 121; https://doi.org/10.3390/electronics7070121
Received: 8 June 2018 / Revised: 12 July 2018 / Accepted: 17 July 2018 / Published: 19 July 2018
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Abstract
This paper presents an electrode with a core/shell geometry and a unique four-layered porous wrinkled surface for pseudocapacitive supercapacitor applications. To design the electrode, Ni foam was used as a substrate, where the harmonious features of four constituents, ZnO (Z), NiS (N), PEDOT:PSS
[...] Read more.
This paper presents an electrode with a core/shell geometry and a unique four-layered porous wrinkled surface for pseudocapacitive supercapacitor applications. To design the electrode, Ni foam was used as a substrate, where the harmonious features of four constituents, ZnO (Z), NiS (N), PEDOT:PSS (P), and MnO2 (M) improved the supercapacitor electrochemical performance by mitigating the drawbacks of each other component. Cyclic voltammetry and galvanostatic charge discharge measurements confirmed that the ZNPM hybrid electrode exhibited excellent capacitive properties in 2 M KOH compared to the ZNP, ZN, and solely Z electrodes. The ZNPM electrode showed superior electrochemical capacitive performance and improved electrical conductivity with a high specific capacitance of 2072.52 F g−1 at 5 mA, and a high energy density of 31 Wh kg−1 at a power density of 107 W kg−1. Overall, ZNPM is a promising combination electrode material that can be used in supercapacitors and other electrochemical energy conversion/storage devices. Full article
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Open AccessArticle An Algorithm of Daubechies Wavelet Transform in the Final Field When Processing Speech Signals
Electronics 2018, 7(7), 120; https://doi.org/10.3390/electronics7070120
Received: 16 June 2018 / Revised: 11 July 2018 / Accepted: 17 July 2018 / Published: 18 July 2018
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Abstract
Development and improvement of a mathematical model for a large-scale analysis based on the Daubechies discrete wavelet transform will be implemented in an algebraic system possessing a property of ring and field suitable for speech signals processing. Modular codes are widely used in
[...] Read more.
Development and improvement of a mathematical model for a large-scale analysis based on the Daubechies discrete wavelet transform will be implemented in an algebraic system possessing a property of ring and field suitable for speech signals processing. Modular codes are widely used in many areas of modern information technologies. The use of these non-positional codes can provide high-speed data processing. Therefore, these algebraic systems should be used in the algorithms of digital processing of signals, which are characterized by processing large amounts of data in real time. In addition, modular codes make it possible to implement large-scale signal processing using the wavelet transform. The paper discusses examples of the Daubechies wavelet transform application. Integer processing, presented in the paper, will reduce the number of rounding errors when processing the speech signals. Full article
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Open AccessArticle Design of a Building-Integrated Photovoltaic System with a Novel Bi-Reflector PV System (BRPVS) and Optimal Control Mechanism: An Experimental Study
Electronics 2018, 7(7), 119; https://doi.org/10.3390/electronics7070119
Received: 29 June 2018 / Revised: 14 July 2018 / Accepted: 17 July 2018 / Published: 18 July 2018
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Abstract
Environment protection and energy saving are the most attractive trends in zero-carbon buildings. The most promising and environmentally friendly technique is building integrated photovoltaics (BIPV), which can also replace conventional buildings based on non-renewable energy. Despite the recent advances in technology, the cost
[...] Read more.
Environment protection and energy saving are the most attractive trends in zero-carbon buildings. The most promising and environmentally friendly technique is building integrated photovoltaics (BIPV), which can also replace conventional buildings based on non-renewable energy. Despite the recent advances in technology, the cost of BIPV systems is still very high. Hence, reducing the cost is a major challenge. This paper examines and validates the effectiveness of low-cost aluminum (Al) foil as a reflector. The design and the performance of planer-reflector for BIPV systems are analyzed in detail. A Bi-reflector solar PV system (BRPVS) with thin film Al-foil reflector and an LLC converter for a BIPV system is proposed and experimented with a 400-W prototype. A cadmium–sulfide (CdS) photo-resistor sensor and an Arduino-based algorithm was developed to control the working of the reflectors. Furthermore, the effect of Al-foil reflectors on the temperature of PV module has been examined. The developed LLC converter confirmed stable output voltage despite large variation in input voltage proving its effectiveness for the proposed BRPVS. The experimental results of the proposed BRPVS with an Al-reflector of the same size as that of the solar PV module offered an enhancement of 28.47% in the output power. Full article
(This article belongs to the Special Issue Innovative Technologies and Services for Smart Cities)
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Open AccessArticle Mechatronic Design and Manufacturing of the Intelligent Robotic Fish for Bio-Inspired Swimming Modes
Electronics 2018, 7(7), 118; https://doi.org/10.3390/electronics7070118
Received: 28 May 2018 / Revised: 27 June 2018 / Accepted: 6 July 2018 / Published: 18 July 2018
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Abstract
This paper presents mechatronic design and manufacturing of a biomimetic Carangiform-type autonomous robotic fish prototype (i-RoF) with two-link propulsive tail mechanism. For the design procedure, a multi-link biomimetic approach, which uses the physical characteristics of a real carp fish as its size and
[...] Read more.
This paper presents mechatronic design and manufacturing of a biomimetic Carangiform-type autonomous robotic fish prototype (i-RoF) with two-link propulsive tail mechanism. For the design procedure, a multi-link biomimetic approach, which uses the physical characteristics of a real carp fish as its size and structure, is adapted. Appropriate body rate is determined according to swimming modes and tail oscillations of the carp. The prototype is composed of three main parts: an anterior rigid body, two-link propulsive tail mechanism, and flexible caudal fin. Prototype parts are produced with 3D-printing technology. In order to mimic fish-like robust swimming gaits, a biomimetic locomotion control structure based on Central Pattern Generator (CPG) is proposed. The designed unidirectional chained CPG network is inspired by the neural spinal cord of Lamprey, and it generates stable rhythmic oscillatory patterns. Also, a Center of Gravity (CoG) control mechanism is designed and located in the anterior rigid body to ensure three-dimensional swimming ability. With the help of this design, the characteristics of the robotic fish are performed with forward, turning, up-down and autonomous swimming motions in the experimental pool. Maximum forward speed of the robotic fish can reach 0.8516 BLs-1 and excellent three-dimensional swimming performance is obtained. Full article
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Open AccessArticle Closing the Wearable Gap: Mobile Systems for Kinematic Signal Monitoring of the Foot and Ankle
Electronics 2018, 7(7), 117; https://doi.org/10.3390/electronics7070117
Received: 7 June 2018 / Revised: 9 July 2018 / Accepted: 13 July 2018 / Published: 18 July 2018
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Abstract
Interviews from strength and conditioning coaches across all levels of athletic competition identified their two biggest concerns with the current state of wearable technology: (a) the lack of solutions that accurately capture data “from the ground up” and (b) the lack of trust
[...] Read more.
Interviews from strength and conditioning coaches across all levels of athletic competition identified their two biggest concerns with the current state of wearable technology: (a) the lack of solutions that accurately capture data “from the ground up” and (b) the lack of trust due to inconsistent measurements. The purpose of this research is to investigate the use of liquid metal sensors, specifically Liquid Wire sensors, as a potential solution for accurately capturing ankle complex movements such as plantar flexion, dorsiflexion, inversion, and eversion. Sensor stretch linearity was validated using a Micro-Ohm Meter and a Wheatstone bridge circuit. Sensors made from different substrates were also tested and discovered to be linear at multiple temperatures. An ankle complex model and computing unit for measuring resistance values were developed to determine sensor output based on simulated plantar flexion movement. The sensors were found to have a significant relationship between the positional change and the resistance values for plantar flexion movement. The results of the study ultimately confirm the researchers’ hypothesis that liquid metal sensors, and Liquid Wire sensors specifically, can serve as a mitigating substitute for inertial measurement unit (IMU) based solutions that attempt to capture specific joint angles and movements. Full article
(This article belongs to the Special Issue Data Processing and Wearable Systems for Effective Human Monitoring)
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Open AccessArticle Distributed-Memory-Based FFT Architecture and FPGA Implementations
Electronics 2018, 7(7), 116; https://doi.org/10.3390/electronics7070116
Received: 11 June 2018 / Revised: 12 July 2018 / Accepted: 13 July 2018 / Published: 17 July 2018
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Abstract
A new class of fast Fourier transform (FFT) architecture, based on the use of distributed memories, is proposed for field-programmable gate arrays (FPGAs). Prominent features are high clock speeds, programmability, reduced look-up-table (LUT) and register usage, simplicity of design, and a capability to
[...] Read more.
A new class of fast Fourier transform (FFT) architecture, based on the use of distributed memories, is proposed for field-programmable gate arrays (FPGAs). Prominent features are high clock speeds, programmability, reduced look-up-table (LUT) and register usage, simplicity of design, and a capability to do both power-of-two and non-power-of-two FFTs. Higher clock speeds are a consequence of new algorithms and a more fine-grained structure compared to traditional pipelined FFTs, so clock speeds are typically >500 MHz in 65 nm FPGA technology. The programmability derives from the memory-based architecture, which is also scalable. Reduced LUT and register usage arises from a unique methodology to control word growth during computation that achieves high dynamic range, along with inherent systolic circuit characteristics: simple, regular, uniform arrays of processing elements, connected in nearest-neighbor fashion to minimize wiring lengths. The circuit goal was to maximize throughput and minimize the use of the FPGA LUT and register logic fabric. Comparison results from seven different designs, covering a spectrum of functionality (fixed-size, variable, floating-point and variable non-power-of-two FFTs), different FPGA vendors (Intel and Xilinx) and different FPGA types, showed increases in throughput per logic cell up to 181% with an average improvement of 94%. Full article
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Open AccessArticle A Novel Technique to Improve the Online Calculation Performance of Nonlinear Problems in DC Power Systems
Electronics 2018, 7(7), 115; https://doi.org/10.3390/electronics7070115
Received: 13 June 2018 / Revised: 11 July 2018 / Accepted: 14 July 2018 / Published: 17 July 2018
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Abstract
The power system is a nonlinear complicated system. For power system analysis problems, they are mainly based on nonlinear equations. In practical systems, the calculation speed of a specific problem is very important. For most classical power system analysis methods, their one-time calculation
[...] Read more.
The power system is a nonlinear complicated system. For power system analysis problems, they are mainly based on nonlinear equations. In practical systems, the calculation speed of a specific problem is very important. For most classical power system analysis methods, their one-time calculation speed with enough accuracy is difficult to be further improved after decades of research. However, if we see many-time calculations of different analysis functions as a whole, the new breakout may be made. This paper aims to present a novel foundational technique to improve the many-time calculation performance of power system problems. With the technique in this paper, the analysis of grid topology, bus types and line parameters can be separated, and the speed of online calculation of some problems can be improved by more than 10 times faster without any sacrifice of accuracy. This paper points out why the holistic speed of many-time calculations has the potential to be largely improved. The concept of a linear relationship based nonlinear problem (LRBNP) is proposed, which is critical to this technique. The detailed theory derivations are carefully performed. The proposed technique also shows a new way to understand the power systems. Finally, the verification of the derived formulas is performed. Full article
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Open AccessFeature PaperArticle Flexible PI-Based Plant Drought Stress Sensor for Real-Time Monitoring System in Smart Farm
Electronics 2018, 7(7), 114; https://doi.org/10.3390/electronics7070114
Received: 22 June 2018 / Revised: 10 July 2018 / Accepted: 13 July 2018 / Published: 16 July 2018
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Abstract
Plant growth and development are negatively affected by a wide range of external stresses, including water deficits. Especially, plants generally reduce the stomatal aperture to decrease transpiration levels upon drought stress. Advanced technologies, such as wireless communications, the Internet of things (IoT), and
[...] Read more.
Plant growth and development are negatively affected by a wide range of external stresses, including water deficits. Especially, plants generally reduce the stomatal aperture to decrease transpiration levels upon drought stress. Advanced technologies, such as wireless communications, the Internet of things (IoT), and smart sensors have been applied to practical smart farming and indoor planting systems to monitor plants’ signals effectively. In this study, we develop a flexible polyimide (PI)-based sensor for real-time monitoring of water conditions in tobacco plants. The stoma response, by which a plant adjusts to drought stress to maintain homeostasis, can be confirmed through the examination of evaporated water. Using a flexible PI-based sensor, a plant’s response variation is translated into an electrical signal. The sensors are integrated with a Bluetooth (BLE) module and a processing module and show potential as smart real-time water sensors in smart farms. Full article
(This article belongs to the Special Issue Flexible/Stretchable Electronics)
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Open AccessArticle An Electromagnetic Analysis of Noise-Based Intrinsically Secure Communication in Wireless Systems
Electronics 2018, 7(7), 113; https://doi.org/10.3390/electronics7070113
Received: 26 April 2018 / Revised: 6 July 2018 / Accepted: 12 July 2018 / Published: 16 July 2018
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Abstract
Recently there has been an increasing interest toward unconditionally secure communication systems in which the mechanism assuring the secrecy of the message is physical and not computational. An interesting approach proposed in the information theory literature for unconditionally secure communication is based on
[...] Read more.
Recently there has been an increasing interest toward unconditionally secure communication systems in which the mechanism assuring the secrecy of the message is physical and not computational. An interesting approach proposed in the information theory literature for unconditionally secure communication is based on the use of artificial noise at a rate related to the difference between the mutual information in perfect secrecy. Since the mechanism assuring the secrecy of the message is physical and not computational, the unauthorized receiver cannot obtain information from the received signal, regardless of how much computational power is available. For this reason, such a cryptographic system is called unconditionally secure. The aim of this paper is to investigate an electromagnetic approach to the noise-based wireless communication systems stressing the important role of the electromagnetic propagation and antenna design. In particular, the concept of the number of degrees of freedom of the field is used to clarify the physical mechanism that allows for a decrease in the mutual information of the unauthorized channel compared to the eavesdropper channel. Numerical examples regarding both free-space propagation and rich scattering environments are shown, confirming the importance of the role of the electromagnetic propagation and antenna design. Full article
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Open AccessReview TSV Technology and High-Energy Heavy Ions Radiation Impact Review
Electronics 2018, 7(7), 112; https://doi.org/10.3390/electronics7070112
Received: 6 June 2018 / Revised: 30 June 2018 / Accepted: 4 July 2018 / Published: 13 July 2018
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Abstract
Three-dimensional integrated circuits (3D IC) based on TSV (Through Silicon Via) technology is the latest packaging technology with the smallest size and quality. As a result, it can effectively reduce parasitic effects, improve work efficiency, reduce the power consumption of the chip, and
[...] Read more.
Three-dimensional integrated circuits (3D IC) based on TSV (Through Silicon Via) technology is the latest packaging technology with the smallest size and quality. As a result, it can effectively reduce parasitic effects, improve work efficiency, reduce the power consumption of the chip, and so on. TSV-based silicon interposers have been applied in the ground environment. In order to meet the miniaturization, high performance and low-cost requirements of aerospace equipment, the adapter substrate is a better choice. However, the transfer substrate, as an important part of 3D integrated circuits, may accumulate charge due to heavy ion irradiation and further reduce the performance of the entire chip package in harsh space radiation environment or cause it to fail completely. Little research has been carried out until now. This article summarizes the research methods and conclusions of the research on silicon interposers and TSV technology in recent years, as well as the influence of high-energy heavy ions on semiconductor devices. Based on this, a series of research methods to study the effect of high-energy heavy ions on TSV and silicon adapter plates is proposed. Full article
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Open AccessFeature PaperArticle Novel Neural Control of Single-Phase Grid-Tied Multilevel Inverters for Better Harmonics Reduction
Electronics 2018, 7(7), 111; https://doi.org/10.3390/electronics7070111
Received: 11 June 2018 / Revised: 2 July 2018 / Accepted: 10 July 2018 / Published: 12 July 2018
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Abstract
A single-phase Cascaded H-Bridge (CHB) grid-tied multilevel inverter is introduced with a detailed discussion of the proposed novel neural controller for better efficiency and power quality in the integration of renewable sources. An LCL (inductor-capacitor-inductor) filter is used in the multilevel inverter system
[...] Read more.
A single-phase Cascaded H-Bridge (CHB) grid-tied multilevel inverter is introduced with a detailed discussion of the proposed novel neural controller for better efficiency and power quality in the integration of renewable sources. An LCL (inductor-capacitor-inductor) filter is used in the multilevel inverter system to achieve better harmonic attenuation. The proposed Neural Network (NN) controller performs the inner current control and tracks the references generated from the outer loop to satisfy the requirements of voltage or power control. Two multicarrier-based Pulse Width Modulation (PWM) techniques (phase-shifted modulation and level-shifted modulation) are adopted in the development of the simulation model to drive the multilevel inverter system for the evaluation of the neural control technique. Simulations are carried out to demonstrate the effectiveness and efficient outcomes of the proposed neural network controller for grid-tied multilevel inverters. The advantages of the proposed neural control include a faster response speed and fewer oscillations compared with the conventional Proportional Integral (PI) controller based vector control strategy. In particular, the neural network control technique provides better harmonics reduction ability. Full article
(This article belongs to the Special Issue Power Quality in Smart Grids)
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Open AccessArticle A Reduced Switch AC-AC Converter with the Application of D-STATCOM and Induction Motor Drive
Electronics 2018, 7(7), 110; https://doi.org/10.3390/electronics7070110
Received: 10 May 2018 / Revised: 3 July 2018 / Accepted: 5 July 2018 / Published: 10 July 2018
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Abstract
In this paper, a reduced switch AC-DC-AC converter is used as a distribution static compensator (DSTATCOM) and induction motor drive. The AC-DC-AC nine switch converter (NSC) is a reduced switch topology of conventional 12-switch back to back converter. With a 25% reduced switch
[...] Read more.
In this paper, a reduced switch AC-DC-AC converter is used as a distribution static compensator (DSTATCOM) and induction motor drive. The AC-DC-AC nine switch converter (NSC) is a reduced switch topology of conventional 12-switch back to back converter. With a 25% reduced switch count, NSC has lower losses when operated at constant frequency mode compared to twelve switch converter (TSC). The idea is to operate NSC input terminal as an active front-end rectifier to mimic synchronous generator (SG) operation. The induction motor is connected at the output of the NSC for irrigation application where no speed regulation is required. In distribution generation (DG), a large capacitor bank is used to deliver required reactive power. This may lead to over-voltage at the point of common coupling (PCC) when the load is turned off. To manage reactive power transfer at PCC, a control scheme is developed for NSC such that it can absorb or deliver reactive power with induction motor drive. Similar to SG, V-curve and inverted V-curve is plotted. The simulation and hardware results prove the feasibility of the proposed system. Full article
(This article belongs to the Special Issue Applications of Power Electronics)
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Open AccessArticle Impact of Quality of Service on Cloud Based Industrial IoT Applications with OPC UA
Electronics 2018, 7(7), 109; https://doi.org/10.3390/electronics7070109
Received: 9 June 2018 / Revised: 3 July 2018 / Accepted: 5 July 2018 / Published: 9 July 2018
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Abstract
The Industrial Internet of Things (IIoT) is becoming a reality thanks to Industry 4.0, which requires the Internet connection of as many industrial devices as possible. The sharing and storing of a huge amount of data in the Cloud allows the implementation of
[...] Read more.
The Industrial Internet of Things (IIoT) is becoming a reality thanks to Industry 4.0, which requires the Internet connection of as many industrial devices as possible. The sharing and storing of a huge amount of data in the Cloud allows the implementation of new analysis algorithms and the delivery of new “services” with added value. From an economical point of view, several factors can decide the success of Industry 4.0 new services but, among others, the “short latency” can be one of the most interesting, especially in the industrial market that is used to the “real-time” concept. For these reasons, this work proposes an experimental methodology to investigate the impact of quality of service parameters on the communication delay from the production line to the Cloud and vice versa, when gateways with OPC UA (Open Platform Communications Unified Architecture) are used for accessing data directly in the production line. In this work, the feasibility of the proposed test methodology has been demonstrated by means of a use case with a Siemens S7 1500 controller exchanging data with the IBM Bluemix platform. The experimental results show that, thanks to the proposed method, the solutions based on OPC UA for the implementation of industrial IoT gateways can be easily evaluated, compared and optimized. For instance, during the 14-day observation period of the considered use case, the great impact on performance of the Quality of Service parameters emerged. Indeed, the average communication delay from the production line to the Cloud may vary from less than 90 ms to about 300 ms. Full article
(This article belongs to the Special Issue Open-Source Electronics Platforms: Development and Applications)
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Open AccessArticle A Variable Speed Pumped Storage System Based on Droop-Fed Vector Control Strategy for Grid Frequency and AC-Bus Voltage Stability
Electronics 2018, 7(7), 108; https://doi.org/10.3390/electronics7070108
Received: 7 May 2018 / Revised: 25 June 2018 / Accepted: 3 July 2018 / Published: 7 July 2018
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Abstract
Harnessing wind energy is the most rapidly growing amongst renewable energy sources. However, because of its intermittency in nature, wind power results in unfavorable influences on power system control, operation and stability. The voltage sag and flicker and grid frequency fluctuation are significant
[...] Read more.
Harnessing wind energy is the most rapidly growing amongst renewable energy sources. However, because of its intermittency in nature, wind power results in unfavorable influences on power system control, operation and stability. The voltage sag and flicker and grid frequency fluctuation are significant in this regard. To minimize the effect of wind power fluctuations and other contingencies on the grid frequency and AC-bus voltage, this paper presents a droop-fed vector control strategy based variable speed pumped storage (VSPS) system comprising the doubly fed induction machine. Modelling of the system is undertaken based on a phasor model technique. The case study is made by considering the droop-controlled VSPS plant in a grid containing conventional synchronous machines for hydropower and thermal power plants and an induction machine wind farm. The performance is validated and analyzed using a MATLAB/Simulink platform. The proposed droop-fed control model is compared with the conventional control strategy (without being droop-fed) and tested to wind power fluctuations, start-up transients, load variations and three-phase fault. The results show that the droop-fed vector control strategy of the VSPS plant achieves better dynamic and steady state controlling responses for grid frequency and AC-bus voltage in the power system than the conventional vector control scheme during wind power fluctuations and contingencies. Full article
(This article belongs to the Special Issue Applications of Power Electronics)
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Open AccessArticle Evaluating the Application of Electrical Resistivity Tomography for Investigating Seawater Intrusion
Electronics 2018, 7(7), 107; https://doi.org/10.3390/electronics7070107
Revised: 31 May 2018 / Accepted: 15 June 2018 / Published: 5 July 2018
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Abstract
Seawater intrusion is a major issue in coastal areas, and the traditional technology of investigation mainly makes use of drilling for water level observation and sample analysis of groundwater; as drilling data is an information of points, it will cost more if it
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Seawater intrusion is a major issue in coastal areas, and the traditional technology of investigation mainly makes use of drilling for water level observation and sample analysis of groundwater; as drilling data is an information of points, it will cost more if it is extended to be information on the surface. Non-destructive geophysical exploration technology has been used in the investigation of the underground environments at all kinds of contaminated sites in recent years. Seawater intrusion is also a groundwater pollution situation, and “Surface and Space” information can be obtained with a small amount of drilling data. This research will use Electric Resistivity Tomography as a geophysical exploration technology to assess the situation at the interface of seawater intrusion and to explore the dynamic changes of seawater intrusion through long-term monitoring. The test site of this research is situated in the seawater intrusion area along Kinmen Island. The research results showed that the front edge of the seawater intrusion could be detected with Electric Resistivity Tomography, and a delay effect existing between seawater intrusion and tidal action was observed by means of Time-lapse. If a long-term observation system is established in future, it could contribute to the confrontation of seawater intrusion and salinization phenomena. Full article
(This article belongs to the Special Issue Selected Papers from the IEEE ICASI 2018)
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Open AccessFeature PaperArticle Development of Environmental Long Range RFID Sensors Based on the Modulated Scattering Technique
Electronics 2018, 7(7), 106; https://doi.org/10.3390/electronics7070106
Received: 31 May 2018 / Revised: 25 June 2018 / Accepted: 29 June 2018 / Published: 4 July 2018
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Abstract
This work presents the development of a wireless sensor system for environmental monitoring based on the modulated scattering technique (MST). The MST sensor probes are based on the scattering properties of small passive antennas and radiate part of the impinging electromagnetic field generated
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This work presents the development of a wireless sensor system for environmental monitoring based on the modulated scattering technique (MST). The MST sensor probes are based on the scattering properties of small passive antennas and radiate part of the impinging electromagnetic field generated by an interrogating antenna, which also acquires the backscattered signal as information. The MST probes are able to deliver data without radio frequency front end. They use a simple circuit that alternatively terminates the antenna probe on suitable loads to generate a low modulation signal on the backscattered electromagnetic wave. In this work, the MST sensor system for environmental monitoring has been proposed to obtain the best performance in communication range, load efficiency and power harvesting. The MST sensor has been fabricated and assessed in practical scenarios. The proposed prototype, able to operate in X band at 10 GHz and able to provide a communication range of about 15 m, serves as a proof-of-concept. The acquired measurements demonstrate that the prototype is able to measure accurately and send data without radio frequency front end or bulky wired connection with the same efficiency of standard wireless sensors such as radio frequency identifier (RFID) or wireless sensor networks (WSN). Full article
(This article belongs to the Special Issue Unconventional RFID Systems)
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Open AccessArticle A Virtual Micro-Islanding-Based Control Paradigm for Renewable Microgrids
Electronics 2018, 7(7), 105; https://doi.org/10.3390/electronics7070105
Received: 27 May 2018 / Revised: 25 June 2018 / Accepted: 28 June 2018 / Published: 4 July 2018
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Abstract
Improvements in control of renewable energy-based microgrids are a growing area of interest. A hierarchical control structure is popularly implemented to regulate key parameters such as power sharing between generation sources, system frequency and node voltages. A distributed control infrastructure is realized by
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Improvements in control of renewable energy-based microgrids are a growing area of interest. A hierarchical control structure is popularly implemented to regulate key parameters such as power sharing between generation sources, system frequency and node voltages. A distributed control infrastructure is realized by means of a communication network that spans the micro-distribution grid. Measured and estimated values, as well as corrective signals are transmitted across this network to effect required system regulation. However, intermittent latencies and failures of component communication links may result in power imbalances between generation sources, deviations in node voltages and system frequency. This paper proposes a hierarchical control structure to regulate the operation of an islanded AC microgrid experiencing communication link failures. The proposed strategy aims to virtually sub-divide the microgrid into controllable “islands”. Thereafter, active power sharing, frequency and voltage restoration is achieved by competing converter systems through multi-agent consensus. The effectiveness of the proposed methodology has been verified through stability analyses using system wide mathematical small signal models and case study simulations in MATLAB, Simpower systems. Full article
(This article belongs to the Special Issue Applications of Power Electronics)
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Open AccessArticle A Low Hardware Consumption Elliptic Curve Cryptographic Architecture over GF(p) in Embedded Application
Electronics 2018, 7(7), 104; https://doi.org/10.3390/electronics7070104
Received: 11 June 2018 / Revised: 26 June 2018 / Accepted: 29 June 2018 / Published: 3 July 2018
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Abstract
In this paper, a low hardware consumption design of elliptic curve cryptography (ECC) over GF(p) in embedded applications is proposed. The adder-based architecture is explored to reduce the hardware consumption of performing scalar multiplication (SM). The Interleaved Modular Multiplication Algorithm and
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In this paper, a low hardware consumption design of elliptic curve cryptography (ECC) over GF(p) in embedded applications is proposed. The adder-based architecture is explored to reduce the hardware consumption of performing scalar multiplication (SM). The Interleaved Modular Multiplication Algorithm and Binary Modular Inversion Algorithm are improved and implemented with two full-word adder units. The full-word register units for data storage are also optimized. The design is based on two full-word adder units and twelve full-word register units of pipeline structure and was implemented on Xilinx Virtex-4 platform. Design Compiler is used to synthesized the proposed architecture with 0.13 μm CMOS standard cell library. For 160, 192, 224, 256 field order, the proposed architecture consumes 5595, 7080, 8423, 9370 slices, respectively, and saves 17.58∼54.93% slice resources on FPGA platform when compared with other design architectures. The synthesized result uses 35.43 k, 43.37 k, 50.38 k, 57.05 k gate area and saves 52.56∼91.34% in terms of gate count in comparison. The design takes 2.56∼4.07 ms to perform SM operation over different field order under 150 MHz frequency. The proposed architecture is safe from simple power analysis (SPA). Thus, it is a good choice for embedded applications. Full article
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Open AccessArticle A Clustering Algorithm for Heterogeneous Wireless Sensor Networks Based on Solar Energy Supply
Electronics 2018, 7(7), 103; https://doi.org/10.3390/electronics7070103
Received: 3 June 2018 / Revised: 21 June 2018 / Accepted: 26 June 2018 / Published: 28 June 2018
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Abstract
Limited battery power directly affects the performance and survival time of sensor networks. In this study, solar energy was used to provide additional energy for sensor nodes, and a clustering algorithm for heterogeneous wireless sensor networks (WSNs) based on a solar energy supply
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Limited battery power directly affects the performance and survival time of sensor networks. In this study, solar energy was used to provide additional energy for sensor nodes, and a clustering algorithm for heterogeneous wireless sensor networks (WSNs) based on a solar energy supply is proposed. A cluster head is selected on the basis of the self-replenishment state and the remaining energy of the nodes. A cluster-head selection mechanism and network layer multi-hop routing are adopted to balance the energy consumption of the network. A set of experiments showed that the proposed algorithm can effectively prolong the network lifetime, improve the stability and efficiency of the network, and balance the energy consumption compared with other algorithms under the same environmental energy supply. Full article
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Open AccessArticle Optimal Control of a Compact Converter in an AC Microgrid
Electronics 2018, 7(7), 102; https://doi.org/10.3390/electronics7070102
Received: 24 May 2018 / Revised: 15 June 2018 / Accepted: 25 June 2018 / Published: 27 June 2018
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Abstract
This paper presents an optimal control method for a compact reduced switch count AC/AC converter in an AC microgrid. The AC/AC converter is adopted to interconnect dual three-phase renewable energy sources (RESs) and a three-phase permanent magnet synchronous motor (PMSM) to the grid
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This paper presents an optimal control method for a compact reduced switch count AC/AC converter in an AC microgrid. The AC/AC converter is adopted to interconnect dual three-phase renewable energy sources (RESs) and a three-phase permanent magnet synchronous motor (PMSM) to the grid to form an example of a mixed grid-feeding-drive system. For the adopted converter, a generalized pulse width modulation (PWM) scheme employing the third harmonic injection and a control method are proposed. Moreover, to achieve reduced dc link voltage ripple, good reference tracking and disturbance rejection, the gains of the controllers are optimized by minimizing a weighted sum of different objective functions. Each objective function represents a specific aspect to be minimized and the optimization problem is solved employing particle swarm optimization (PSO) method, while ensuring that the total harmonic distortion (THD) of the current at the points of common coupling (PCC) are less than 5%. For this mixed grid-feeding-drive system, simulation results under fast transient are provided to demonstrate the applicability of the adopted converter in the AC microgrid, the effectiveness of the proposed PWM, and the proposed optimal control method. Full article
(This article belongs to the Special Issue Renewable Electric Energy Systems)
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Open AccessArticle A Three-Dimensional Enhanced Imaging Method on Human Body for Ultra-Wideband Multiple-Input Multiple-Output Radar
Electronics 2018, 7(7), 101; https://doi.org/10.3390/electronics7070101
Received: 4 June 2018 / Revised: 20 June 2018 / Accepted: 22 June 2018 / Published: 25 June 2018
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Abstract
High-resolution three-dimensional (3D) images can be acquired by the planar Multiple-Input Multiple-Output (MIMO) array radar making future work like detection and tracking easier. However, regarding portability and to save the costs of radar system, MIMO radar array adopts sparse type with limited number
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High-resolution three-dimensional (3D) images can be acquired by the planar Multiple-Input Multiple-Output (MIMO) array radar making future work like detection and tracking easier. However, regarding portability and to save the costs of radar system, MIMO radar array adopts sparse type with limited number of antennas, so the imaging performance of a MIMO radar system is limited. In this paper, the 3D back projection imaging algorithm is verified by the experimental results of planar MIMO array for human body and an enhanced radar imaging method is proposed. The Lucy-Richardson (LR) algorithm based on deconvolution that is normally used for optical images is applied in radar images. Since the LR algorithm can amplify the noise level in a noise-contaminated system, a regularization method based on the Total Variation constraint is further incorporated in the LR algorithm to suppress the ill-posed characteristics. The proposed method shows a higher image Signal-to-Noise Ratio, a faster rate of convergence, a higher structure similarity and a smaller relative error compared to some similar methods. In the meantime, it also reduces the loss of image information after image enhancement and improves the radar image quality (get less grating lobe and clearer human limbs). The proposed method overcomes the disadvantages mentioned above and is verified by simulation experiment and real data measurement. Full article
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Open AccessArticle Optimizing Generation Capacities Incorporating Renewable Energy with Storage Systems Using Genetic Algorithms
Electronics 2018, 7(7), 100; https://doi.org/10.3390/electronics7070100
Received: 23 May 2018 / Revised: 15 June 2018 / Accepted: 16 June 2018 / Published: 21 June 2018
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Abstract
In grid advancement, energy storage systems are playing an important role in lowering the cost, reducing infrastructural investment, ensuring reliability and increasing operational capability. The storage system can provide stabilization services and is pivotal for backup power for emergencies. With a continuous rise
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In grid advancement, energy storage systems are playing an important role in lowering the cost, reducing infrastructural investment, ensuring reliability and increasing operational capability. The storage system can provide stabilization services and is pivotal for backup power for emergencies. With a continuous rise in fuel prices and increasing environmental issues, the energy from renewable resources is gaining more popularity. The main drawbacks of some renewable sources are their intermittent energy generation and uncertain source availability, which has increased interest in energy storage systems (ESSs). This paper investigates the economic feasibility when ESSs are introduced in the electric grid with an expansion of a storage system as well as more percentage of the renewable energy integration and less percentage of fuel consumption by conventional power sources. The Artificial Neural Network is implemented to validate the forecasted load model. The uncertainties associated with the renewable energy system are handled by a chance-constrained model and solved by a genetic algorithm (GA) in MATLAB; selection criteria of GA for optimization process is also discussed in detail. The effectivity of the proposed methodology is verified by applying it to a case that lies in the western region of China. Full article
(This article belongs to the Special Issue Renewable Electric Energy Systems)
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