Showing papers on "Topology (electrical circuits) published in 2018"
17 Apr 2018
TL;DR: This paper presents an overview of recent work in decentralized optimization and surveys the state-of-theart algorithms and their analyses tailored to these different scenarios, highlighting the role of the network topology.
Abstract: In decentralized optimization, nodes cooperate to minimize an overall objective function that is the sum (or average) of per-node private objective functions. Algorithms interleave local computations with communication among all or a subset of the nodes. Motivated by a variety of applications..decentralized estimation in sensor networks, fitting models to massive data sets, and decentralized control of multirobot systems, to name a few..significant advances have been made toward the development of robust, practical algorithms with theoretical performance guarantees. This paper presents an overview of recent work in this area. In general, rates of convergence depend not only on the number of nodes involved and the desired level of accuracy, but also on the structure and nature of the network over which nodes communicate (e.g., whether links are directed or undirected, static or time varying). We survey the state-of-theart algorithms and their analyses tailored to these different scenarios, highlighting the role of the network topology.
397 citations
TL;DR: In this article, a single phase switched-capacitor multilevel inverters (SCMLI) is presented, where the same two capacitors paralleled to a single dc source are connected to each other with a new extended configuration.
Abstract: In this paper, a novel platform for the single phase switched-capacitor multilevel inverters (SCMLIs) is presented. It has several advantages over the classical topologies, such as an appropriate boosting property, higher efficiency, lower number of required dc voltage sources, and other accompanying components with less complexity and lower cost. The basic structure of the proposed converter is capable of making nine-level of the output voltage under different kinds of loading conditions. Hereby, by using the same two capacitors paralleled to a single dc source, a switched-capacitor (SC) cell is made that contributes to boosting the value of the input voltage. In this case, the balanced voltage of the capacitors can be precisely provided on the basis of the series–parallel technique and the redundant switching states. Afterward, to reach the higher number of output voltage levels, two suggested SC cells are connected to each other with a new extended configuration. Therefore, by the use of a reasonable number of required power electronic devices, and also by utilizing only two isolated dc voltage sources, which their magnitudes can be designed based on either symmetric or asymmetric types, a 17- and 49-level of the output voltage are obtained. Based on the proposed extended configuration, a new generalized version of SCMLIs is also derived. To confirm the precise performance of the proposed topologies, apart from the theoretical analysis and a complete comparison, several simulation and experimental results are also given.
303 citations
TL;DR: In this paper, the authors proposed a non-isolated high step-up dc-dc converter with dual coupled inductors suitable for distributed generation applications, which inherits shared input current with low ripple, which also requires small capacitive filter at its input.
Abstract: This paper introduces a non-isolated high step-up dc–dc converter with dual coupled inductors suitable for distributed generation applications. By implementing an input parallel connection, the proposed dc–dc structure inherits shared input current with low ripple, which also requires small capacitive filter at its input. Moreover, this topology can reach high voltage gain by using dual coupled inductors in series connection at the output stage. The proposed converter uses active clamp circuits with a shared clamp capacitor for the main switches. In addition to the active clamp circuit, the leakage energy is recycled to the output by using an integrated regenerative snubber. Indeed, these circuits allow soft-switching conditions, i.e., zero voltage switching and zero current switching for active and passive switching devices, respectively. The mentioned features along with a common ground connection of the input and output make the proposed topology a proper candidate for transformer-less grid-connected photovoltaic systems. The operating performance, analysis and mathematical derivations of the proposed dc–dc converter have been demonstrated in the paper. Moreover, the main features of the proposed converter have been verified through experimental results of a 1-kW laboratory prototype.
287 citations
TL;DR: A novel transformerless high gain step-up dc–dc converter based on an active switched-inductor and a passive switched-capacitor networks that has the main advantages of the high voltage gain (>10), the reduced voltage stresses across the switches and the reduced number of components when compared to topologies that provide the same voltage gain using similar principles.
Abstract: High-gain voltage conversion is a feature required for several applications, especially for power processing of low-voltage renewable sources in grid-connected systems. In this scope, the presented paper proposes a novel transformerless high gain step-up dc–dc converter based on an active switched-inductor and a passive switched-capacitor networks. The main advantages of the proposed converter are the high voltage gain (>10), the reduced voltage stresses across the switches and the reduced number of components when compared to topologies that provide the same voltage gain using similar principles. The detailed analysis of the proposed converter and a comparison considering other topologies previously published in the literature are also presented in this manuscript. In order to verify the proposed converter performance, a prototype has been built for a power of 200 W, input and output voltages of 20 and 260 V, respectively, and switching frequency of 50 kHz. Experimental results validate the effectiveness of the theoretical analysis proving the satisfactory converter performance, which peak efficiency is around 95.5%.
272 citations
TL;DR: In this paper, the authors proposed a new module for asymmetrical multilevel inverters with a low number of components, which is a square combination of two back-to-back T-type inverters and some other switches.
Abstract: This paper introduces a new module for asymmetrical multilevel inverters with a low number of components. The module is a square combination of two back-to-back T-type inverters and some other switches. A square T-type module produces 17 levels by 12 switches and 4 unequal dc sources (two 3 V DC and two 1 V DC). Also, it can be extended as a cascade connection in two strategies to achieve more levels. The module and its cascade connection are suitable for the applications in several dc sources systems such as photovoltaic farms, which lead to a modular topology with more voltage levels at higher voltages. Inherent creation of the negative voltage levels without any additional circuit (such as H-bridge circuit) is one of the main features of the proposed module. The low total harmonic distortion of the output voltage/current and low number of semiconductors are among the other advantages of the proposed module. A nearest level control method as a switching technique is used to produce high quality output voltage with lower harmonic contents. Simulations have been performed in MATLAB/Simulink and a prototype is implemented in the Power Electronics Laboratory; both the simulation and experimental results show a good performance.
246 citations
01 Jan 2018
TL;DR: A novel model, called LC-RNN, is proposed, to achieve more accurate traffic speed prediction than existing solutions, which takes advantage of both RNN and CNN models by a rational integration of them.
Abstract: Traffic speed prediction is known as an important but challenging problem. In this paper, we propose a novel model, called LC-RNN, to achieve more accurate traffic speed prediction than existing solutions. It takes advantage of both RNN and CNN models by a rational integration of them, so as to learn more meaningful time-series patterns that can adapt to the traffic dynamics of surrounding areas. Furthermore, since traffic evolution is restricted by the underlying road network, a network embedded convolution structure is proposed to capture topology aware features. The fusion with other information, including periodicity and context factors, is also considered to further improve accuracy. Extensive experiments on two real datasets demonstrate that our proposed LC-RNN outperforms seven well-known existing methods.
190 citations
TL;DR: In this paper, a modified pulse width modulated LLC type resonant topology (PWM-LLC) is proposed and investigated in PEV charging applications, where the switching frequency of the primary LLC network is constant and equal to the resonant frequency.
Abstract: In conventional LLC-based plug-in electric vehicle (PEV) onboard chargers, the battery pack voltage varies in a wide range with the change of state of charge. This makes it difficult to optimally design the pulse frequency modulated LLC resonant converter. Besides, the voltage regulation of the LLC converter is highly dependent on the load conditions. In this paper, a modified pulse width modulated (PWM) LLC type resonant topology (PWM-LLC) is proposed and investigated in PEV charging applications. The switching frequency of the primary LLC network is constant and equal to the resonant frequency. The voltage regulation is achieved by modulating the duty cycle of the secondary side auxiliary mosfet . Compared with the conventional LLC topology, the proposed topology shrinks the magnetic component size and achieves a wide and fixed voltage gain range independent of load conditions. Meanwhile, zero-voltage-switching and zero-current-switching are realized among all MOSFETs and diodes, respectively. A 100-kHz, 1-kW converter prototype, generating 250–420 V output from the 390-V dc link, is designed and tested to verify the proof of concept. The prototype demonstrates 96.7% peak efficiency and robust performance over wide voltage and load ranges.
187 citations
TL;DR: A comparative analysis of the recent topology reveals that the proposed S3CM topology achieves switch count reduction and voltage boosting gain of two, and the number of isolated dc sources is significantly reduced compared to a cascaded H-bridge.
Abstract: A two-stage switched-capacitor based multilevel inverter possesses a drawback such that switches in the second stage (i.e., H-bridge) endure higher voltage stress. To resolve this problem, this letter proposes a single-stage switched-capacitor module (S3CM) topology for cascaded multilevel inverter, which ensures the peak inverse voltage across all the switches within the dc source voltage. A total of nine voltage levels can be generated with only one dc source and two incorporated capacitors. Hence, the number of isolated dc sources is significantly reduced compared to a cascaded H-bridge. In addition, voltage boosting gain of two is achieved. A comparative analysis of the recent topology reveals that the proposed S3CM topology achieves switch count reduction. The operation of the proposed topology is validated through circuit analysis followed by simulation and experimental results of a single-module (9-level) prototype.
172 citations
TL;DR: The proposed method involves the application of principal component analysis and its graph-theoretic interpretation to infer the steady state network topology from smart meter energy measurements and is demonstrated through simulation on randomly generated networks and on IEEE recognized Roy Billinton distribution test system.
Abstract: In a power distribution network, the network topology information is essential for an efficient operation. This network connectivity information is often not available at the low voltage (LV) level due to uninformed changes that happen from time to time. In this paper, we propose a novel data-driven approach to identify the underlying network topology for LV distribution networks including the load phase connectivity from time series of energy measurements. The proposed method involves the application of principal component analysis and its graph-theoretic interpretation to infer the steady state network topology from smart meter energy measurements. The method is demonstrated through simulation on randomly generated networks and also on IEEE recognized Roy Billinton distribution test system.
169 citations
TL;DR: This paper firstly project the approaching vehicles from different traffic movements into a virtual lane and introduces a conflict-free geometry topology considering the conflict relationship of involved vehicles, thus constructing a virtual platoon, and presents the modeling of communication topology to describe two modes of information transmission between vehicles.
Abstract: Connected vehicles will change the modes of future transportation management and organization, especially at intersections. In this paper, we propose a distributed conflict-free cooperation method for multiple connected vehicles at unsignalized intersections. We firstly project the approaching vehicles from different traffic movements into a virtual lane and introduce a conflict-free geometry topology considering the conflict relationship of involved vehicles, thus constructing a virtual platoon. Then we present the modeling of communication topology to describe two modes of information transmission between vehicles. Finally, a distributed controller is designed to stabilize the virtual platoon for conflict-free cooperation at intersections. Numerical simulations validate the effectiveness of this method.
162 citations
TL;DR: In this paper, a switched-capacitor bidirectional dc-dc converter with a high step-up/stepdown voltage gain is proposed for electric vehicles with a hybrid energy source system.
Abstract: A switched-capacitor bidirectional dc–dc converter with a high step-up/step-down voltage gain is proposed for electric vehicles with a hybrid energy source system. The converter presented has the advantages of being a simple circuit, a reduced number of components, a wide voltage-gain range, a low voltage stress, and a common ground. In addition, the synchronous rectifiers allow zero voltage switching turn-on and turn-off without requiring any extra hardware, and the efficiency of the converter is improved. A 300 W prototype has been developed, which validates the wide voltage-gain range of this converter using a variable low-voltage side (40–100 V) and to give a constant high-voltage side (300 V). The maximum efficiency of the converter is 94.45% in step-down mode and 94.39% in step-up mode. The experimental results also validate the feasibility and the effectiveness of the proposed topology.
TL;DR: A multi-layered lens comprises a plurality of metasurface layers that at least some layers include features that exhibit angular phase controls that cause an angular aberration correction or an angle convergence that focuses light onto a focal point regardless of angles of incidence.
Abstract: Compact metasurface devices herald an exciting revolution in optics technology. Their design complexity and functionality has been restricted to intuitive by-hand designs for single-layered devices. This study proposes a large-scale approach known as topology optimization, applied to multiple, closely spaced device layers, which greatly expands the scope and functionality of metadevices. In particular, the authors demonstrate angular phase control, the ability to encode arbitrary information using different angles of incidence, which enables $e.g.$ the design of a one-piece, aberration-corrected metalens, and of an angle-convergent metalens.
TL;DR: In this article, an error-in-variables model in a maximum-likelihood estimation framework for joint line parameter and topology estimation is proposed. But the model is not suitable for mesh networks.
Abstract: The increasing integration of distributed energy resources calls for new planning and operational tools. However, such tools depend on system topology and line parameters, which may be missing or inaccurate in distribution grids. With abundant data, one idea is to use linear regression to find line parameters, based on which topology can be identified. Unfortunately, the linear regression method is accurate only if there is no noise in both the input measurements (e.g., voltage magnitude and phase angle) and output measurements (e.g., active and reactive power). For topology estimation, even with a small error in measurements, the regression-based method is incapable of finding the topology using nonzero line parameters with a proper metric. To model input and output measurement errors simultaneously, we propose the error-in-variables model in a maximum-likelihood estimation framework for joint line parameter and topology estimation. While directly solving the problem is NP-hard, we successfully adapt the problem into a generalized low-rank approximation problem via variable transformation and noise decorrelation. For accurate topology estimation, we let it interact with parameter estimation in a fashion that is similar to expectation-maximization algorithm in machine learning. The proposed PaToPa approach does not require a radial network setting and works for mesh networks. We demonstrate the superior performance in accuracy for our method on IEEE test cases with actual feeder data from Southern California Edison.
TL;DR: In this paper, the authors proposed a six-plate capacitive coupler for large air-gap capacitive power transfer to reduce electric field emissions to the surrounding environment, which can eliminate the external parallel capacitor in the previous LCLC topology, which results in the LCL compensation and reduces system cost.
Abstract: This paper proposes a six-plate capacitive coupler for large air-gap capacitive power transfer to reduce electric field emissions to the surrounding environment. Compared to the conventional four-plate horizontal structure, the six-plate coupler contains two additional plates above and below the inner four-plate coupler to provide a shielding effect. Since there is a capacitive coupling between every two plates, the six-plate coupler results in a circuit model consisting of 15 coupling capacitors. This complex model is first simplified to an equivalent three-port circuit model, and then to a two-port circuit model which is used in circuit analysis and parameter design. This six-plate coupler can eliminate the external parallel capacitor in the previous LCLC topology, which results in the LCL compensation and reduces the system cost. Due to the symmetry of the coupler structure, the voltage between shielding plates is limited, which reduces electric field emissions. Finite element analysis by Maxwell is used to simulate the coupling capacitors and electric field distribution. Compared to the four-plate horizontal and vertical structures, the six-plate coupler can significantly reduce electric field emissions and expand the safety area from 0.9 to 0.1 m away from the coupler in the well-aligned case. A 1.97 kW prototype is implemented to validate the six-plate coupler, which achieves a power density of 1.95 kW/m2 and a dc–dc efficiency of 91.6% at an air-gap of 150 mm. Experiments also show that the output power maintains 65% of the well-aligned value at 300 mm X misalignment, and 49% at 300 mm Y misalignment.
TL;DR: A distributed adaptive sliding mode control scheme for more realistic vehicular platooning is presented, which does not require the exact values of each entity in the topological matrix, and only needs to know the bounds of its eigenvalues.
Abstract: In a platoon control system, a fixed and symmetrical topology is quite rare because of adverse communication environments and continuously moving vehicles. This paper presents a distributed adaptive sliding mode control scheme for more realistic vehicular platooning. In this scheme, adaptive mechanism is adopted to handle platoon parametric uncertainties, while a structural decomposition method deals with the coupling of interaction topology. A numerical algorithm based on linear matrix inequality is developed to place the poles of the sliding motion dynamics in the required area to balance quickness and smoothness. The proposed scheme allows the nodes to interact with each other via different types of topologies, e.g., either asymmetrical or symmetrical, either fixed or switching. Different from existing techniques, it does not require the exact values of each entity in the topological matrix, and only needs to know the bounds of its eigenvalues. The effectiveness of this proposed methodology is validated by bench tests under several conditions.
TL;DR: In this article, a hybrid and reconfigurable inductive power transfer (IPT) system with 3-D misalignment tolerance for CC and CV outputs is proposed, simplifying or even canceling control schemes.
Abstract: Inductive power transfer (IPT) for battery charging applications has significant advantages over the traditional plug-in system. Since misalignment between the primary and secondary windings is inevitable, it is of significance to improve the misalignment tolerance of IPT systems with constant-current (CC) and constant-voltage (CV) outputs for battery charging. In this paper, the load-independent output characteristic of the hybrid topology and the function switching between CC and CV of the reconfigurable topology are analyzed. Besides, a hybrid and reconfigurable IPT system with 3-D misalignment tolerance for CC and CV outputs is proposed, simplifying or even canceling control schemes. Moreover, a novel parametric design method is given for the IPT system, which can suppress the fluctuation of the output voltage/current within a certain range of misalignment. In order to validate the performance of the proposed topology, a 1-kW prototype is built, and the corresponding experiments are carried out. In the CC/CV mode, the system can operate with the longitudinal misalignment to 50% when the load varies from 36 to 480 Ω, and the fluctuation of the output current/voltage is within 5%. Similarly, the misalignment in Y - and Z -axis is 12.5% and 33.3%, respectively.
TL;DR: The use of topology control algorithms for a suitable, autonomous, and on-the-fly organization of the UWSN topology might mitigate the undesired effects of underwater wireless communications and consequently improve the performance of networking services and protocols designed for UWSNs.
Abstract: Underwater wireless sensor networks (UWSNs) will pave the way for a new era of underwater monitoring and actuation applications. The envisioned landscape of UWSN applications will help us learn more about our oceans, as well as about what lies beneath them. They are expected to change the current reality where no more than 5% of the volume of the oceans has been observed by humans. However, to enable large deployments of UWSNs, networking solutions toward efficient and reliable underwater data collection need to be investigated and proposed. In this context, the use of topology control algorithms for a suitable, autonomous, and on-the-fly organization of the UWSN topology might mitigate the undesired effects of underwater wireless communications and consequently improve the performance of networking services and protocols designed for UWSNs. This article presents and discusses the intrinsic properties, potentials, and current research challenges of topology control in underwater sensor networks. We propose to classify topology control algorithms based on the principal methodology used to change the network topology. They can be categorized in three major groups: power control, wireless interface mode management, and mobility assisted–based techniques. Using the proposed classification, we survey the current state of the art and present an in-depth discussion of topology control solutions designed for UWSNs.
TL;DR: The ability to achieve high gains is the main merit of the proposed topology, and the converter achieves high step-up voltage gain with appropriate duty cycle and low voltage and current stress on the power switches and diodes.
Abstract: In this paper, a new nonisolated high step-up dc–dc converter is proposed. Active–passive inductor cells (APICs) are used to extend the topology. The ability to achieve high gains is the main merit of the proposed topology. The proposed converter operates based on parallel charging and series discharging of the inductors. The converter also achieves high step-up voltage gain with appropriate duty cycle and low voltage and current stress on the power switches and diodes. The proposed converter is analyzed in operation modes. The main parameters of the converter such as voltage gain, voltage stress of semiconductor devices are calculated to compare with other structures. Considering the output voltage ripple and filter size, the proposed converter is designed. Moreover, the losses and efficiency of the converter are calculated. The performance of the proposed converter is validated by experimental results.
TL;DR: This letter presents an improved sensorless nine-level inverter topology with reduced number of components formed by cascading a three-level T-type neutral clamped point inverter with a floating capacitor fed two-level converter unit.
Abstract: This letter presents an improved sensorless nine-level inverter topology with reduced number of components. It is formed by cascading a three-level T-type neutral clamped point inverter with a floating capacitor (FC) fed two-level converter unit. Additionally, two line-frequency switches are appended across the dc-link. A simple logic-form equations-based pulse width modulator is designed which is in-charge of maintaining the FC voltage at its reference value without any aid of voltage and current sensor. Thus, the complexity in control of the proposed topology is very minimal. The working principle of the proposed inverter and formulation of logic-form equations is deliberated in detail. Furthermore, experimental results obtained from the developed prototype are presented to validate feasibility and operability of the proposed topology. Finally, a comprehensive comparison with some of the recently reported inverter topologies proving the merits of the proposed topology is included.
TL;DR: The VNE-NTANRC algorithm adopts a novel node-ranking approach to rank all substrate and virtual nodes before embedding each given VN, and Simulation results reveal that V NE-NTAnRC algorithm outperforms typical and latest heuristic algorithms, only considering single network topology attribute and local resources.
Abstract: Network virtualization (NV) is a promising approach to remove the ossification of current Internet. Virtual network embedding (VNE) is the key issue in NV which efficiently and effectively maps various of virtual networks (VNs), with different node and link resource requests, onto the shared substrate network(s) with finite underlying resources. Previous VNE algorithms in the literature are mostly heuristic. Single network topology attribute and each node’s local resources are assisted to rank nodes in most heuristic algorithms, leading to inefficient resource utilization of substrate network in the long run. To deal with this issue, we propose the network topology attribute and network resource-considered algorithm (VNE-NTANRC). The VNE-NTANRC algorithm adopts a novel node-ranking approach to rank all substrate and virtual nodes before embedding each given VN. The novel node-ranking approach has two subapproaches and considers five important network topology attributes and global network resources altogether. One subapproach is able to calculate all node values (NoV) directly. The other subapproach, stimulating from the Google PageRank website algorithm, enables to calculate NoVs in a stable state. Simulation results reveal that VNE-NTANRC algorithm outperforms typical and latest heuristic algorithms, only considering single network topology attribute and local resources.
TL;DR: Experimental tests developed in this paper show the capability of controling the grid currents in the synchronous reference frame in order to provide grid services, which makes this matrix converter ideal for battery charging of electric vehicles and energy storage applications.
Abstract: This paper presents a new modulation and control strategies for the high-frequency link matrix converter (HFLMC). The proposed method aims to achieve controllable power factor in the grid interface as well as voltage and current regulation for a battery energy storage device. The matrix converter (MC) is a key element of the system, since it performs a direct ac to ac conversion between the grid and the power transformer, dispensing the traditional dc-link capacitors. Therefore, the circuit volume and weight are reduced and a longer service life is expected when compared with the existing technical solutions. A prototype was built to validate the mathematical analysis and the simulation results. Experimental tests developed in this paper show the capability of controling the grid currents in the synchronous reference frame in order to provide grid services. Simultaneously, the battery current is well regulated with small ripple, which makes this converter ideal for battery charging of electric vehicles and energy storage applications.
TL;DR: In this paper, an improved symmetrical 4-level submodule is proposed as a basic cell for generating multiple dc voltage levels, which reduces the number of conducting switch and gate driver requirements compared to the widely used half-bridge submodule.
Abstract: This letter proposes an improved symmetrical 4-level submodule as a basic cell for generating multiple dc voltage levels. A hybrid cascaded multilevel inverter (HCMLI) topology is formed by the combination of n submodules and a full-bridge. A comparative analysis against the recent multilevel inverters reveals that the proposed topology requires less number of switches and dc sources. In addition, the proposed submodule reduces the number of conducting switch and gate driver requirements compared to the widely used half-bridge submodule. To validate the operation of the proposed HCMLI topology, experimental results of a 9-level single-phase inverter controlled by selective harmonic elimination pulse-width-modulation is presented.
TL;DR: The proposed Time-series signature verification method for topology detection performs the projection of actual voltage phasorial patterns onto a library of signals associated with possible topology transictions of a given distribution network.
Abstract: This paper proposes a novel method for topology detection in distribution networks called the Time-series signature verification method for topology detection ( TSV-Top ). The TSV-Top analyzes data from phasor measurement units (PMU or $\mu$ PMU) installed on power distribution feeders. The TSV-Top relies on the fact that measurement data time series from power systems contain similar trends when network topology changes occur, and basically performs the projection of actual voltage phasorial patterns onto a library of signals associated with possible topology transictions of a given distribution network. The proposed algorithm is validated using a 33-bus testbed and the IEEE 123-bus feeder, and then compared with another state-of-the-art algorithm using the IEEE 37-bus feeder.
TL;DR: A three-phase grid-connected photovoltaic (PV) topology (named H8) is proposed to address the leakage current issue and results validate the performance improvements of H8 inverter in terms of leakage current and total harmonic distortion of the output currents injected into the grid.
Abstract: In this paper, a three-phase grid-connected photovoltaic (PV) topology (named H8) is proposed to address the leakage current issue. AC common-mode voltage and earth leakage current cause problems in the transformerless grid-connected PV systems. Leakage current increases the distortion of the current injected into the grid and the losses, also it generates unwanted radiated and conducted electromagnetic interference. The voltage source full-bridge inverter, which is also known as B6-type converter is widely used for three-phase PV systems. The B6-type inverter suffers from the leakage current, which limits its application to transformerless grid-connected PV systems. The proposed H8 topology reduces the leakage current as well as common-mode voltage variations through the separation of the PV array from the grid during the zero voltage states. Through analysis, simulations, and experimental results, a comparison between the proposed topology and the conventional B6-type topology is performed. Results validate the performance improvements of H8 inverter in terms of leakage current and total harmonic distortion of the output currents injected into the grid. Experimental results are presented for a 2-kW grid-connected PV system.
TL;DR: In this paper, a synthesis methodology for developing a set of very high step-up dc-dc converters is presented and discussed, in which three stepup techniques are combined and incorporated.
Abstract: A synthesis methodology for developing a set of very high step-up dc–dc converters is presented and discussed in this paper. The proposed method makes use of a boost converter as basic topology in which three step-up techniques are combined and incorporated. The studied techniques are the switched capacitors voltage multipliers (VM), the diode VMs, and the coupled-inductors. With the proposed methodology, many well-known converters are identified and two novel converters are proposed. In addition to a detailed analysis of the synthesis of each topology, a comparative analysis among of some important converters is presented. This comparison involves aspects such as voltage gain, voltage stress, component stress factor, component count, and relative cost. By means of these comparisons, the main characteristics and constraints of the analyzed converters are identified. Results from 250 W prototypes, designed according to photovoltaic ac-module specifications, are obtained experimentally to validate the theoretical analyses and point out advantages and limitations of each converter. The results demonstrate that the combination of the three studied techniques provides the best trend off on the comparative analysis carried out in this work.
TL;DR: The priority of this work is to obtain some conditions which ensure the underlying complex dynamical network (CDN) is stochastically synchronized with a stated L 2 -- L ∞ performance level.
TL;DR: A new topology of switched-capacitor (SC) multileVEL inverter, which is able to step-up input DC voltage to a multilevel AC waveform, is presented, which eliminates requirements of H-bridge inverters that are traditionally used to achieve a bipolar output voltage.
Abstract: This study presents a new topology of switched-capacitor (SC) multilevel inverter, which is able to step-up input DC voltage to a multilevel AC waveform. This single source inverter is designed based on series connection of the capacitors that charged by input DC sources through a SC network. The proposed modular inverter uses famous T and cross-connected modules that can be simply extended to higher output voltages without increasing the amount of total standing voltage and peak inverse voltage of switches. It generates positive and negative voltage levels inherently, which eliminates requirements of H-bridge inverters that are traditionally used to achieve a bipolar output voltage. Analysis shows that the voltage stress on components, cost, efficiency and losses are kept in acceptable range especially for higher-voltage levels. Capacitor's voltage self-balancing is another inherent advantage of this modular topology which leads to simplify control strategy and eliminate excess balancing circuit. Performance of a six-step proposed structure is evaluated by theoretical analysis, simulation and experimental results.
TL;DR: A single-switch quadratic buck–boost converter with continuous input port current and continuous output port current is proposed in this paper and can obtain a wider range of the voltage conversion ratio with the same duty cycle.
Abstract: A single-switch quadratic buck–boost converter with continuous input port current and continuous output port current is proposed in this paper. Compared with the traditional buck-boost converter, the proposed converter can obtain a wider range of the voltage conversion ratio with the same duty cycle. Moreover, the proposed converter can operate with continuous input port current and continuous output port current compared to the existing counterparts with inherently discontinuous input port current and discontinuous output port current. The operating principle and steady-state performance of the proposed converter under continuous inductor current mode is analyzed in detail. Then, the comparison between the proposed converter and the existing quadratic buck–boost converters has been conducted to demonstrate the unique features of the proposed one. Finally, experimental results from a prototype built in the lab are recorded to verify the effectiveness and validity of the proposed quadratic buck–boost converter.
TL;DR: This paper proves that the estimates of unknown parameters converge to the actual values by presenting a new theorem, which is generalized for the heterogeneous platoons with time-varying network topology.
Abstract: This paper deals with the adaptive control and identification of 1-D platoon of non-identical vehicles. Three common different topologies, such as predecessor following, bi-directional leader following, and two predecessors following are considered as the communication structures of platoon. For each topology, a new neighbor-based adaptive control law is introduced to estimate the parameter uncertainties, such as rolling resistance and air drag force coefficients. By presenting a new theorem, we prove that the estimates of unknown parameters converge to the actual values. Constant time headway policy is used to adjust the inter-vehicle spacing. For each topology, it is shown that the closed-loop dynamics of platoon is asymptotically stable. Afterward, the necessary conditions on control parameters assuring the string stability for each topology are derived by presenting further theorems. Moreover, the proposed methods are generalized for the heterogeneous platoons with time-varying network topology. Simulation results with different scenarios are provided to show the effectiveness of the presented approaches.
TL;DR: A novel nonisolated single-input dual-output three-level dc–dc converter appropriate for medium- and high-voltage applications and shows very good stability, even under simultaneous step changes of the loads and input voltage.
Abstract: This paper proposes a novel nonisolated single-input dual-output three-level dc–dc converter (SIDO-TLC) appropriate for medium- and high-voltage applications. The SIDO-TLC is an integration of the three-level buck and boost converters, whose output voltages are regulated simultaneously. Reducing voltage stress across semiconductor devices, improving efficiency, and reducing inductors size are among the main merits of the new topology. Moreover, due to the considerably reduced volume of the step-down filter capacitor, a small film capacitor can be used instead, whose advantages are lower equivalent series resistance and a longer lifespan. A closed-loop control system has been designed based on a small-signal model derivation in order to regulate the output voltages along with the capacitors’ voltage balancing. In order to verify the theoretical and simulation results, a 300-W prototype was built and experimented. The results prove the aforementioned advantages of the SIDO-TLC, and the high effectiveness of the balancing control strategy. Furthermore, the converter shows very good stability, even under simultaneous step changes of the loads and input voltage.