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In this article, we propose steady-state modeling of dc–dc converters driven by multiple pulsewidth modulation (PWM) signals. The proposed dc–dc converter modeling uses a switched state-space framework, and the switching signal discontinuities are represented by a Fourier series to obtain the average model. The advantage of the proposed modeling is that it is not dependent on the dc–dc converter topology, and the dimension of the state-space model does not increase with the number of storage devices. Additionally, the duty cycle and phase displacements among the driving PWM signals can be arbitrary and systematically modeled. The effectiveness of the proposed modeling is supported by simulation and experimental results. [ABSTRACT FROM AUTHOR]

To lower the high computational burden of nonlinear filter in the practical applications, the previous paper has proposed the adaptive algorithm based on the joint process filter using pipelined feedforward second-order Volterra architecture (JPPSOV). Even though the JPPSOV adaptive filter has been common used for nonlinear systems identification, nonlinear active noise controller (ANC) and nonlinear acoustic echo cancellers (AEC), there is currently no literature that gives the steady state analysis of JPPSOV. Therefore, we analyze the steady state performance of the LMS adaptive algorithm of the JPPSOV filter for nonlinear system identification in this brief. Finally, the simulated results are in good agreement with the theoretical results. [ABSTRACT FROM AUTHOR]

Increasing penetration of power electronics is changing the understanding of modern power systems. In particular, current saturation of converters leads to multiple equilibrium points for both normal and short-circuit conditions. This paper aims to identify equilibrium points in power systems with penetration of power electronics. First, a steady-state model of power systems considering the power electronics operation is presented. Then, a general methodology is developed to obtain equilibrium points including all possible combinations of converter current saturation states. A system of equations is defined for each combination and is solved considering the possibility to have single or multiple solutions. This methodology is suitable for steady-state analysis in normal operation and during short-circuit scenarios. Test systems with Voltage Source Converters are used to validate the presented methodology.

This work proposes positive- and negative-sequence equivalent circuits of grid-forming inverters for steady-state analysis. The proposed models are especially attractive for performing long-duration voltage regulation analysis and short-circuit studies involving grid-forming inverters. Our proposed equivalent circuit models are based on the inverter’s voltage and current control loops in the $\alpha \beta $ and dq frames. For this reason, they operate according to prescribed control functions and specified impedances (i.e., filter impedance, current limiter block, virtual admittance block, and PI/PR controller block). The equivalent circuit model accuracy is validated by comparing system steady-state voltage and current responses obtained by detailed time-domain models in PSCAD/EMTDC to those by the equivalent circuit models implemented in steady-state load flow program (e.g., OpenDSS). Two distinct control structures implemented in the $\alpha \beta $ and dq frames are used for the validation. Single line-to-ground and line-to-line-to-ground faults are simulated in a small islanded microgrid as well as the IEEE 34-node test feeder. Fault impedances varying from 0 to 5 ohms are simulated. We show that the equivalent models precisely replicate the steady-state response of the detailed time-domain models.

This paper introduces the concept of inductors asymmetric input voltage to derive a new high voltage gain converter. The proposed converter has continuous input, positive output, and high-power density features suitable for renewable energy applications. The operating principle, steady-state performance, practical voltage gain, small-signal analysis, and efficiency of the converter are presented in this work. A comprehensive comparison is made with the high voltage gain converters available in literature in terms of component count, voltage gain, effectiveness index, voltage and current stress on the power devices, per unit switching device rating, and other features like output polarity and availability of common ground. The proposed topology possesses a higher effectiveness index and lower switching device power rating (SDP), resulting in a good form factor. To validate the performance of the proposed converter, the experiments are conducted on the 150 W laboratory prototype, and corresponding results are presented in this work.

This paper studies load balancing for many‐server (N servers) systems. Each server has a buffer of size b − 1, and can have at most one job in service and b − 1 jobs in the buffer. The service time of a job follows the Coxian‐2 distribution. We focus on steady‐state performance of load balancing policies in the heavy traffic regime such that the normalized load of system is λ = 1 − N−α for 0 < α < 0.5. We identify a set of policies that achieve asymptotic zero waiting. The set of policies include several classical policies such as join‐the‐shortest‐queue (JSQ), join‐the‐idle‐queue (JIQ), idle‐one‐first (I1F) and power‐of‐d‐choices (Po d) with d = O(Nα log N). The proof of the main result is based on Stein's method and state space collapse. A key technical contribution of this paper is the iterative state space collapse approach that leads to a simple generator approximation when applying Stein's method. [ABSTRACT FROM AUTHOR]

Designing Fair and Efficient Matching Service Systems The first-come, first-served (FCFS) service discipline provides a simple, and more importantly, fair method to allocate limited service capacity to customers and to manage queues. At the same time, it can limit the ability of service providers to optimize this allocation based on individual customers' preferences and servers' characteristics. To address this limitation, providers can segment demand into classes and serve them using different subsets of servers on an FCFS basis. The hope is that, by appropriately selecting the subset of servers that may serve each customer class, the service provider can improve service quality (i.e., matching customers to their most preferred servers) without increasing (significantly) waiting times. In "On the Optimal Design of a Bipartite Matching Queueing System," Afèche, Caldentey, and Gupta propose a queueing framework (inspired by the seminal work of Edward Kaplan on public housing) to solve this matching design problem. The proposed methodology allows service providers to construct a Pareto frontier of service menus that efficiently trade-off the quality of the matching and customers' waiting times. We consider a multiclass multiserver queueing system and study the problem of designing an optimal matching topology (or service compatibility structure) between customer classes and servers under a first come first served—assign longest idle server (FCFS-ALIS) service discipline. Specifically, we are interested in finding matching topologies that optimize—in a Pareto efficiency sense—the trade-off between two competing objectives: (i) minimizing customers' waiting time delays and (ii) maximizing matching rewards generated by pairing customers and servers. Our analysis of the problem is divided into three main parts. First, under heavy-traffic conditions, we show that any bipartite matching system can be partitioned into a collection of complete resource pooling (CRP) subsystems, which are interconnected by means of a direct acyclic graph (DAG). We show that this, together with the aggregate service capacity on each CRP, fully determines the vector of steady-state waiting times. In particular, we show that the average (scaled) steady-state delay across all customer classes is asymptotically equal to the number of CRP components divided by the total system capacity. Second, since computing matching rewards under a FCFS-ALIS service discipline is computationally infeasible as the number of customer classes and servers grow large, we propose a quadratic programming (QP) formulation to approximate matching rewards. We show that the QP formulation is exact for a number of instances of the problem and provides a very good approximation in general. Extensive numerical experiments show that in over 98% of problem instances the relative error between the exact rewards and the QP approximate rewards is less than 2%. Lastly, combining our characterization of average delays in terms of the number of CRP components and the QP formulation to compute matching rewards, we propose a mixed-integer linear program that can be used to find the set of matching topologies that define the Pareto frontier of reward-delay pairs. [ABSTRACT FROM AUTHOR]

In this paper, a new hybrid SEPIC dc-dc converter with coupled inductors suitable for photovoltaic applications is presented. First, how the new topology was derived will be presented, continuing with its analysis and design equation as a standalone dc-dc topology. The analysis will consist of a steady-state equations derivation, a static conversion ratio calculation based on which the semiconductor voltage and current stresses are evaluated and states the continuous conduction mode (CCM) operation conditions. The converter will then be simulated as a first validation of the theory using the dedicated Caspoc power electronics package. To finally validate the theoretical design, a prototype will be built in order to practically demonstrate the feasibility of the proposed solution and to reveal its main practical features and limitations. A comparative study to several other similar topologies will be carried out to identify its most desirable feature. Finally, an application of the new hybrid converter will consist of a complete solar energy conversion system using a photovoltaic panel. The maximum power point tracking (MPPT) algorithm will be elaborated. The solar system together with the MPPT will first be modeled, then simulated and practically implemented and tested. [ABSTRACT FROM AUTHOR]

Abstract A new variable step-size strategy for the least mean square (LMS) algorithm is presented for distributed estimation in adaptive networks using the diffusion scheme. This approach utilizes the ratio of filtered and windowed versions of the squared instantaneous error for iteratively updating the step-size. The result is that the dependence of the update on the power of the error is reduced. The performance of the algorithm improves even though it is at the cost of added computational complexity. However, the increase in computational complexity can be minimized by careful manipulation of the update equation, resulting in an excellent performance-complexity trade-off. Complete theoretical analysis is presented for the proposed algorithm including stability, transient and steady-state analyses. Extensive experimental analysis is then done to show the performance of the proposed algorithm under various scenarios.

We consider a single-server retrial queue with a Poisson arrival process and exponential service times, where the server is unreliable. Assume there is no waiting space in front of the server and the customer who finds the server unavailable joins an orbit to access the server some time later. We discuss two types of customers' retrial behavior. One is that each customer in the orbit seeks for services independently and the total retrial rate of the system depends on the number of customers in the orbit. The other type of retrial discipline is called constant retrial policy and it arises from some situations in the computer and communication network where the retrial rate may be controlled by automatic mechanisms. An announced price charged by the server is imposed on customers joining the system and the actual demands for services depend on the price via a decreasing function. We investigate the system characteristics and study how the manager, whose goal is to maximize its own profit, determines the price charging joining customers. Finally, we present an application example to illustrate the obtained results and make comparisons between the two retrial policies from the perspective of customers' expected waiting time.

This paper presents a study of the effect wavelet selection has on the density of the Jacobian matrix and nodal waveform coefficients of wavelet based periodic steady-state analysis of electrical circuits. For the presented case studies, it is shown that a simulation in the time domain produces a sparser Jacobian matrix than a simulation in the wavelet domain if no frequency domain elements are present. When frequency domain elements are present, some wavelets may produce marginally lower densities than the time domain with the advantage of a sparser representation of the circuit waveforms. Additionally, a new method for automatically selecting the threshold used when removing low amplitude elements in the Jacobian matrix at each iteration is introduced and tested.

Queues or waiting lines are an integral part of health care facilities such as hospitals, outpatient clinics, medical laboratories, and many other health facilities. Health care management must have waiting lines control strategies for smooth functioning. Due to the lack of proper queuing control and management, patients may become dissatisfied and may leave (renege) the health care facilities without getting service. But, the reneging of patients at two consecutive time marks may be correlated in the sense that if a patient reneges at the current time mark, then there is a probability that a patient may or may not renege at the next time mark. This kind of reneging is referred to as correlated reneging. In this paper, we have introduced the concept of correlated reneging in a finite capacity multi-server queuing model with balking with its application in health care. The steady-state as well as the transient analyses of the model are carried out. We have also derived an expression for the correlation coefficient between the inter-reneging times and for the rate at which the health facility is losing patients (patient loss probability) due to insufficient capacity, reneging, and balking. We have provided numerical examples in order to demonstrate the effect of balking and correlated reneging on performance measures such as the mean number of patients waiting to be serviced, mean waiting time of patients, and the probability of patient rejection. Further, the effect of the number of servers on performance measures is investigated. Finally, the effect of the correlation coefficient between the inter-reneging times on performance measures is studied. The queuing model discussed in this paper could be useful to the health care firms facing the problem of patient impatience and capacity constraints.

Amyloid polypeptide (IAPP) fibril formation is the main cause of type II diabetes mellitus (T2DM) disease and cardiovascular disease (CVD). Therefore, implementing therapeutic interventions strategies to control IAPP fibril formation plays a crucial role in preventing and managing T2DM disease and CVD. For this purpose, in this paper, we make use of a mathematical model to investigate the effects of drug therapy on the dynamics of amyloid fibril formation (or amyloid plaques). The model is a hybrid system of differential equations consisting of ODEs and (hyperbolic) PDE. The (global) stability analysis is established through the construction of suitable Lyapunov functionals and application of Lasalle's invariance principle. Moreover, stability of the disease steady state is fully determined by a threshold condition, which is based on the total population of IAPP polymers.

In this work, a new class of stochastic gradient algorithm is developed based on fractional calculus. Unlike the existing algorithms, the concept of complex fractional gradient is introduced by employing Caputo's fractional derivative which results in a fractional steepest descent algorithm and a fractional-order complex LMS (FoCLMS) algorithm. We demonstrate that with the Caputo's fractional gradient definition, the Weiner solution remains invariant. Convergence analysis of the proposed FoCLMS algorithm is presented for both transient and steady state scenarios. Consequently, expressions for the learning curves and steady state EMSE are derived. Our theoretical developments are validated by simulation experiments. Extensive simulations are presented to investigate all possible scenarios: channel with negative weights and real input data, channel with positive weights and complex input data, and channel with complex weights and complex input data. [ABSTRACT FROM AUTHOR]

Summary: In this paper, two cascaded buck‐boost nature converters are developed; one converter is capable of producing high step‐up gain, and the other converter addresses high step‐down gain. In proposed converters, for a given voltage gain, two distinct duty ratios are possible due to their ability in handling complementary switching schemes. This feature is effective for voltage‐sensitive applications like LED systems. The operation principle, steady‐state analysis, and the design of the passive components for each switching scheme are presented for the proposed converters. Comparative analysis with competitive converters profound the merits of the proposed converters in terms of voltage gain and the continuous nature of the output. Experiments are conducted on both proposed converters for simultaneous and complementary switching schemes, and they validate the theoretical steady‐state performance. [ABSTRACT FROM AUTHOR]

In this paper, a steady-state model of an LLC resonant half-bridge converter with internal loss resistance is proposed, in order to maximize power conversion efficiency, and steady-state characteristic equations of DC voltage gain and input impedance are derived for the optimal design of the converter. First, to confirm the validity of the steady-state characteristic equation and the optimal design process, a prototype converter with a maximum output of 2 kW was designed. Through comparison of simulation, calculation, and experimental results obtained from the prototype test, it is shown that the calculation results proposed in this paper were closer to the experimental results than the calculation results obtained under the lossless condition. In addition, the relationship between the switching frequency and the load current of the prototype was compared, in order to determine the operating range of the switching frequency, which is important in the converter design stage. In this case, it was confirmed that the calculated value reflecting the internal loss showed a close result. In conclusion, we confirm the usefulness of the analysis results reflecting the internal loss resistance proposed in this paper and the optimal design process.

The paper addresses an optimization-based reference calculation method for Modular Multilevel Converters (MMC) operating in normal and constrained situations (when the converter needs to prioritize its quantities as it has reached voltage or current limitations, e.g. during system faults). The optimization problem prioritizes to satisfy the external AC active and reactive current set-points demanded by the grid operator through the corresponding grid code. If the operator demands are fulfilled, it uses the available MMC degrees of freedom to minimize the arm inductance losses. Otherwise, if the operator demanded AC set-points cannot be accomplished, the optimization attempts to minimize the error prioritizing between either AC active or reactive currents. The optimization problem constraints are imposed through a steady-state model considering simultaneously the external and internal AC and DC magnitudes of the converter. The steady-state model also includes the voltage variation in the equivalent arm capacitors (considering the ripple). Then, the imposed limitations are the maximum allowed grid and arm currents, the maximum allowed arm voltages and the sub-module capacitor maximum voltages. The paper presents a detailed formulation of the optimization problem and applies it to several case studies where it is shown that the presented approach can be potentially used to obtain the MMC references both in normal and fault conditions. [ABSTRACT FROM AUTHOR]

This paper presents the improved methodology for the direct calculation of steady-state periodic solutions for electromagnetic devices, as described by nonlinear differential equations, in the time domain. A novel differential operator is developed for periodic functions and the iterative algorithm determining periodic steady-state solutions in a selected set of time instants is identified. Its application to steady-state analysis is verified by an elementary example. The modified algorithm reduces the complexity of steady-state analysis, particularly for electromagnetic devices described by high-dimensional nonlinear differential equations.

Due to many advantages, such as cost-effective production, design freedom, and weight reduction, plastics have replaced metals and ceramics in many fields. However, engineering plastics are good thermal insulators. This characteristic, although beneficial in certain applications, poses many challenges in many heat-generating applications. This can lead to hot spots or even to an increase in the device temperature. Along with the increasing demand for plastics in areas of the lighting technology or in the automotive field due to the free shaping potential, the requirements are becoming more challenging. Driven by the trend of miniaturization, applications with high heat generation often have to operate in the tightest of spaces. Since not always sufficient space for complex cooling systems is given, the housing or the substrate should assume the task of thermal management. In regard to this fact, the use of thermally conductive thermoplastics seems to be very appealing. Quality loss, poorer reliability, loss of performance, and even failure can occur in case of insufficient heat dissipation. In order to improve the properties of these polymers, highly heat-conducting fillers are added in order to improve the thermal conductivity of the compound. Another technology trend that has been prevalent for years is the use of simulations. Due to shorter product life cycles and therefore shorter development times, simulation has become an indispensable part of the chain of product development. Time-consuming and costly test series make the simulation more and more important as a tool for material and product design. In this context, this paper presents a novel approach for reliability investigation and lifetime estimation, based on simulation. Therefore, a simulative method based on coupling the results from the process simulation (injection molding simulation) to finite element analysis was developed and explained. This coupled method makes it possible to take into account the manufacturing process and its engendered filler orientation. The obtained findings are compared to conventional thermal steady-state analysis and used in order to better predict the lifetime of LEDs mounted on thermoplastic substrates, the so-called molded interconnect devices. It is demonstrated that it is necessary to consider the filler orientation, especially in the case of 3D substrates.

The hyperbolic cosine function with high-order errors can be utilized to improve the accuracy of adaptive filters. However, when initial weight errors are large, the hyperbolic cosine-based adaptive filter (HCAF) may be unstable. In this paper, a novel normalization based on the logarithmic hyperbolic cosine function is proposed to achieve the stabilization for the case of large initial weight errors, which generates a logarithmic HCAF (LHCAF). Actually, the cost function of LHCAF is the logarithmic hyperbolic cosine function that is robust to large errors and smooth to small errors. The transient and steady-state analyses of LHCAF in terms of the mean-square deviation (MSD) are performed for a stationary white input with an even probability density function in a stationary zero-mean white noise. The convergence and stability of LHCAF can be therefore guaranteed as long as the filtering parameters satisfy certain conditions. The theoretical results based on the MSD are supported by the simulations. In addition, a variable scaling factor and step-size LHCAF (VSS-LHCAF) is proposed to improve the filtering accuracy of LHCAF further. The proposed LHCAF and VSS-LHCAF are superior to HCAF and other robust adaptive filters in terms of filtering accuracy and stability. [ABSTRACT FROM AUTHOR]

This paper presents a new average behavioral model, named a resistor-network (RN) model, that accurately predicts the electrical characteristics of the Dickson charge pump (DCP) circuit in the slow-switching limit and the fast-switching limit regions based on steady-state analysis. The RN model describes the steady-state behavior of a single-stage DCP using a network of resistors, which can then be cascaded to model N-stage DCP, taking into account the top- and bottom-plate parasitic capacitances. The RN model provides a comprehensive insight into various design parameters of the DCP, including the input/output current, output voltage, load characteristics, losses caused by parasitics, and power efficiency. Simulation results show that the proposed RN model accurately predicts the output voltage and power efficiency of the DCP over a wide range of switching frequencies, from 0.1 Hz to 1 GHz, with an error of less than 2% at the maximum power efficiency. The RN model provides designers with a simple and effective model to design DCP quickly and efficiently for a broad spectrum of applications, including energy harvesting and flash memory applications.

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The phenomenon of balking has been considered frequently in the steady-state analysis of the M/M/1 queueing system. Balking means the phenomenon that a customer who arrives at a queueing system leaves without joining a queue, since he/she is disgusted with the waiting queue length at the moment of his/her arrival. In the traditional studies for the steady-state analysis of the M/M/1 queueing system with balking, it has been typically assumed that the arrival rates obey an inverse proportional function for the waiting queue length. In this study, based on the concept of the statistical mechanics, we have a challenge to extend the traditional steady-state analysis model for the M/M/1 queueing system with balking. As the result, we have defined an extended analysis model for the M/M/1 queueing system under the consideration of the change in the directivity strength of balking. In addition, the procedure for estimating the strength of balking in this analysis model using the observed data in the M/M/1 queueing system has been also constructed. [ABSTRACT FROM AUTHOR]

Steady-state measurements in a thermogravitational microcolumn using optical digital interferometry are presented here for the first time in the literature in the case of ternary mixtures. These measurements enabled the subsequent obtaining of thermodiffusion coefficients of a ternary mixture once convection reaches the steady-state. The ternary mixture used was the benchmark one, tetrahydronaphthalene (THN) – isobutylbenzene (IBB) and n-dodecane (nC12) with mass fraction of 0.8-0.1-0.1 respectively. Contrast factors due to the change in the concentration field were measured and compared with the corresponding ones in the literature. Uncertainty in the results was found to be of similar order of magnitude as in the case of Selectable Optical Diagnostic Instrument (SODI), which means that the condition number of that contrast factor matrix is almost equal to the present one. Final values of thermodiffusion coefficients were compared with the results reported from other optical techniques, as well as with the results obtained by the traditional long opaque thermogravitational columns (TGC). Some proposals were then made in order to improve accuracy reducing the condition number of the contrast factor matrix. [ABSTRACT FROM AUTHOR]

This study proposes a new transformerless DC–DC step‐down converter having the quadratic type of wider voltage gain, for point‐of‐load applications. In comparison to existent quadratic buck converter variants, the proposed topology offers better switch utilisation at small output voltages and reduced voltage/current stress on components. The stress minimisation benefit helps to select low ON‐state resistance switch in the proposed converter, thereby decreasing its conduction losses. Qualitative steady‐state analysis is carried out under continuous inductor current mode and design criteria for L‐C components are established. State‐space average model is derived and subsequently, an equivalent sliding mode control law based on just source side inductor current dynamics and integral of load voltage error is constituted to regulate the output. Salient operational characteristics of the converter are studied analytically and illustrated thereafter using experimental outcomes on a laboratory prototype. [ABSTRACT FROM AUTHOR]

The conventional converter needs to be operated at a high duty cycle to achieve maximum possible voltage gain. This leads to severe reverse recovery of switches, increases losses, and reduces efficiency. This study presents a modified switched‐capacitor‐based high gain continuous input current quasi‐Z‐source converter (qZSC) for DC microgrid applications. The proposed converter utilises the embedded switched‐capacitor techniques and can give a high voltage gain with a low duty ratio compared to the conventional converters. The proposed converter also experiences less capacitor voltage and inductor current stresses compared to the conventional Z‐source converters. This facilitates the use of lower‐rated capacitors and inductors for higher power applications. Detailed steady‐state, small‐signal, and power loss analysis of proposed qZSC is discussed in this study. A prototype of 100 W is designed and implemented using TI TMS320F28335 Experimenter Kit to verify the operation of the proposed converter. [ABSTRACT FROM AUTHOR]

Amyloid polypeptide (IAPP) fibril formation is the main cause of type II diabetes mellitus (T2DM) disease and cardiovascular disease (CVD). Therefore, implementing therapeutic interventions strategies to control IAPP fibril formation plays a crucial role in preventing and managing T2DM disease and CVD. For this purpose, in this paper, we make use of a mathematical model to investigate the effects of drug therapy on the dynamics of amyloid fibril formation (or amyloid plaques). The model is a hybrid system of differential equations consisting of ODEs and (hyperbolic) PDE. The (global) stability analysis is established through the construction of suitable Lyapunov functionals and application of Lasalle's invariance principle. Moreover, stability of the disease steady state is fully determined by a threshold condition, which is based on the total population of IAPP polymers. [ABSTRACT FROM AUTHOR]

Cyber attacks can cause cascading failures and blackouts in smart grids. Therefore, it is highly necessary to identify the types, impacts and solutions of cyber attacks to ensure the secure operation of power systems. As a well-known practice, steady-state analysis is commonly used to identify cyber attacks and provide effective solutions. However, it cannot fully cover non-linear behaviours and cascaded blackouts of the system caused by dynamic perturbations, as well as provide a post-disturbance operating point. This study presents a novel approach based on dynamic analysis that excludes the limitations of the steady-state analysis and can be used in the events of various cyber attacks. Four types of common attacks are reviewed, and their dynamic impacts are shown on the IEEE benchmark model of the Western System Coordinating Council system implemented in MATLAB Simulink. Then, recommendations are provided to enhance the security of the future smart power grids from the possible cyber attacks.

In this paper, a new hybrid SEPIC dc-dc converter with coupled inductors suitable for photovoltaic applications is presented. First, the way how the new topology was derived will be presented, continuing with its analysis and design equation as a standalone dc-dc topology. The analysis will consist of a steady-state equations derivation, a static conversion ratio calculation based on which the semiconductor voltage and current stresses are evaluated, leading to the continuous conduction mode (CCM) operation conditions. The converter will then be simulated as a first validation of the theory using the dedicated Caspoc power electronics package. To finally validate the theoretical design, a prototype will be built in order to practically demonstrate the feasibility of the proposed solution and to reveal its main practical features and limitations. A comparative study to several other similar topologies will be carried out to identify its most desirable features. Finally, an application of the new hybrid converter will consist of a complete solar energy conversion system using a photovoltaic panel. The maximum power point tracking (MPPT) algorithm will be elaborated. The solar system together with the MPPT will first be modeled, then simulated and practically implemented and tested.

A single-switch high boost DC–DC converter is introduced in this work. In the suggested topology, a voltage multiplier cell and three-winding coupled inductor (CL) are integrated to obtain an ultra-large conversion ratio. Using a passive clamp circuit and also, no requirement of larger duty cycle values enable the converter to have a very high voltage gain, low conduction loss, and reduced voltage stress of semiconductors. Moreover, the leakage inductance of the CL alleviated diodes reverse recovery problem. Some important merits include ultra-high voltage gain, operating in low duty cycles, reduced voltage stress of semiconductors, continuous input current, high efficiency, and low turn ratio of the CL makes the introduced converter very suitable for renewable energy applications. Steady-state analysis and operation principles of the presented topology are expressed completely in the study. Moreover, the theoretical efficiency analysis and design guidelines of the suggested configuration are presented. Also, the superiority of the presented topology over the state-of-the-art similar DC–DC converters is demonstrated in the comparison study. Eventually, the validity of theoretical analysis is verified using experimental measurement results of the implemented prototype with a power rating of 240 W and an output voltage of 440 V. [ABSTRACT FROM AUTHOR]

Some configurations of universal active power filter (UAPF) with uninterruptible power supplies (UPSs) features for single‐phase applications are proposed in this study focus on a reduced number of power electronic switches. All proposed configurations, composed by two‐leg converters, compensate for current and voltage harmonics and provide power factor control close to one. Comparisons between the structures are made in terms of converters voltage capabilities, shared‐leg, and capacitor currents. The model of the systems, including the equations and control system, is detailed described. Steady‐state analysis of the proposed configurations demonstrates the existence of a load angle, which reduces the converters current, increasing the efficiency of the proposed systems. A complete set of simulated and experimental results are presented. [ABSTRACT FROM AUTHOR]

A lot of research has been done in the diffusion paradigm for the wireless sensor networks. However, not enough attention has been given to the incremental strategy. Despite having better performance than the diffusion scheme, incremental based algorithms have been generally ignored. This brief presents an incremental variable step-size strategy for distributed estimation. A detailed analysis of the performance of the algorithm is shown. The mean analysis and mean square analysis are given along with steady-state results. The mean square analysis, as presented here, is being performed for the first time and provides closed form results, unlike previous works present in the literature. [ABSTRACT FROM AUTHOR]

The modular multilevel converter (MMC) is a popular research topic in power electronics and is a promising topology for high-power applications. Many steady-state analysis models have been investigated for MMCs. The circular interaction among the electrical quantities in an MMC has been established and improved models have been proposed, with consideration of the second-order circulating current controller and line harmonic currents in the analysis. So far, no steady-state analysis models have addressed the effect of averaging voltage regulation control, which influences switching function of MMC upper and lower arms, and finally, the accuracy of steady-state analysis. In this article, we discuss the validity of existing models with and without averaging control. After extensive simulations, it is found that the accuracy is affected, showing the weakness of existing models and verifying the effect of averaging voltage regulation control on steady-state analysis of MMCs. Then, to solve this problem, an improved analysis model is proposed. In this model, averaging control is considered at the beginning of circular-interaction-based analysis. The new model presents a higher accuracy compared with the existing ones. [ABSTRACT FROM AUTHOR]

A three‐phase interleaved high step‐up bidirectional DC–DC converter is proposed, which can achieve three times the voltage gain of the traditional three‐phase interleaved boost converter only by adding two capacitors. The proposed converter has the characteristics of low switch voltage and current stresses, low output voltage ripple, automatic voltage‐balancing and current‐sharing abilities. Compared with the traditional interleaved switching strategy, a 180° interleaved switching strategy is proposed, which is more suitable for the proposed converter by widening the working duty cycle range. Closed dual‐loop control is used to regulate the output voltage of the converter. The parameter determining the method of the closed‐loop controllers based on the Bode diagram is described in order to control the high‐order converter. Operating principle, modelling, steady‐state analysis, voltage‐balancing and current‐sharing ability analysis and closed‐loop design of the converter are studied in more detail. Finally, experimental verification and efficiency measurements are implemented by a 300 W, 24 V input to 230 V DC bus prototype, which proved that the proposed converter is more suitable than the traditional three‐phase interleaved boost converter for some applications where requiring about six to ten times the voltage conversion ratio. [ABSTRACT FROM AUTHOR]

This study deals with steady-state analysis and control of a step-up interleaved winding cross-coupled inductor DC–DC converter with high voltage gain and reduced voltage stress across semiconductors using voltage multiplier cells (VMCs). Because of the interleaved scheme, the thermal stress is reduced and the input current ripple is minimised. The leakage energy is recycled by passive lossless clamp circuit to the output. Meanwhile, the voltage stress across the semiconductors is substantially low. Hence, MOSFETs with less ON-state resistances and diodes with a less forward voltage drop can be utilised that improves the circuit performance. The operation principle and the steady state are discussed. Small-signal modelling of the proposed converter is derived via state-space averaging technique and a dual loop controller for output voltage regulation is designed. The adopted strategy utilises a fast dynamical inner loop to control the input current and an outer loop for the output voltage regulation. Finally, a 1 kW prototype with 60 V–1 kV voltage conversion is fabricated and tested to probe the carried analysis. [ABSTRACT FROM AUTHOR]

Normal phase-shift and modified pulse-width modulation gating schemes are proposed for a full bridge high-frequency capacitor–inductor–inductor (CLL) resonant DC–DC converter, and its performance is analysed in this study. Detailed modelling and the steady-state analysis of the converter are performed by using the fundamental harmonic approximation approach. Various modes of the converter operation with both the gating schemes are described and examined in detail. Zero-voltage switching of all the main switches is achieved by designing the resonant converter to operate in the above resonance mode. The optimum design of the converter is illustrated with the help of a flowchart and design curves. PSIM simulation is carried out and the experimental prototype is built to substantiate theoretical performance predictions. The simulation and experimental results are presented and compared. [ABSTRACT FROM AUTHOR]

In this study, a modified DC–DC converter is proposed, which can achieve a high voltage-gain exploiting both quasi-Z-source and switched-capacitor networks. In addition to the high voltage-gain, the proposed converter has low voltage stresses on its elements. The steady-state analysis in both continuous and discontinuous conduction modes is given in this study. Moreover, the design of the passive elements, the calculation of the non-ideal voltage gain, and the power loss analysis are done. Then, an extended topology of the proposed converter is presented, which further enhances the voltage gain, while maintaining the voltage stresses of the components. A comprehensive comparison with the prior-art converters is performed to accentuate the advantages of the proposed converter. Finally, simulations and experimental tests are provided to substantiate the theoretical analysis. [ABSTRACT FROM AUTHOR]

Modular Multilevel Converter (MMC) with the addition of average voltage model (AVM) has increased the efficiency, performance and scalability for voltage source converter (VSC) within multi-terminal high voltage direct current (MT-HVdc) network. When this technology is integrated into the large HVdc transmission system, electromagnetic-transients (EMT) complicates the study of transient's states. Unlike complex modelling, a simple and better understanding of the AVM in VSC stations helps to improve the dynamic control performance in the large transmission system hence, improving steady and transient states. This paper presents the solution, by using state space analysis of a four terminal test grid, to optimize control parameters of VSC stations. In order to validate the desirable performance of AVM under dynamic states, practical scenarios have been simulated using PSCAD/EMTDC software. Simulation results are presented and its state-space analysis is also studied. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to review and compare two methodologies to solve the power flow problem considering active power generation droop control. The first methodology is based on a DC power flow model, and the second one is based on a conventional full Newton power flow formulation. The study of two test systems is used to validate the proposed analysis; the first one is the 11-bus system with two distinct areas, and the second one is the 39-bus New England power system. The results presented validate and indicate the effectiveness of the DC power flow approach in order to estimate the steady-state system frequency deviations. [ABSTRACT FROM AUTHOR]

A new variable step-size strategy for the least mean square (LMS) algorithm is presented for distributed estimation in adaptive networks using the diffusion scheme. This approach utilizes the ratio of filtered and windowed versions of the squared instantaneous error for iteratively updating the step-size. The result is that the dependence of the update on the power of the error is reduced. The performance of the algorithm improves even though it is at the cost of added computational complexity. However, the increase in computational complexity can be minimized by careful manipulation of the update equation, resulting in an excellent performance-complexity trade-off. Complete theoretical analysis is presented for the proposed algorithm including stability, transient and steady-state analyses. Extensive experimental analysis is then done to show the performance of the proposed algorithm under various scenarios. [ABSTRACT FROM AUTHOR]

Stationary detectors are widely used in the urban area, such as loops and traffic cameras, providing with aggregated macroscopic quantities as well as individual pass-by records that could reveal the cluster features of the traffic flow. The paper proposes a multi-lane platoon based (MLP) model that can be calibrated with stationary data. A steady-state analysis is conducted to derive the model's internal capacity constraints (ICC). It is proved in the validation that the ICC mechanism could effectively decrease 60% of the unnatural boundary controls in the simulation system. [ABSTRACT FROM AUTHOR]

The future electric grid will consist of significant penetration of renewable and distributed generation that is likely to create a homogenous transmission and distribution (T&D) system, requiring tools that can model and robustly simulate the combined T&D networks. Existing tools use disparate models and formulations for simulation of transmission versus distribution grids and solving for the steady-state solution of the combined T&D networks often lacks convergence robustness and scalability to large systems. In this paper, we show that modeling both the T&D grid elements in terms of currents and voltages using an equivalent circuit framework enables simulation of combined positive sequence networks of the transmission grids with three-phase networks of the distribution grids without loss of generality. We further demonstrate that we can ensure robust convergence for these resulting large-scale complex T&D systems when the circuit simulation methods are applied to them. Our results illustrate robust convergence of combined T&D networks using a direct Newton-Raphson solver on a single machine for smaller sized systems and using a parallel Gauss-Seidel-Newton solver on multiple machines for larger sized systems with greater than million nodes. [ABSTRACT FROM AUTHOR]

In many different ways, solar energy has been studied in many ways. Continuous reduction in the prices of solar photovoltaic systems makes solar energy more efficient compared to other types of renewable energies. The main points of the use of solar panels are subject to high penetration of electric power supply for remote areas. Considering this concept rather than the design and fabrication of transmission lines, it reduces the total power system losses and increases the reliability and overall system stability of the system. However, distributed power generation may cause significant voltage regulation and problems in the power system. This paper examines the effect of high penetration photovoltaic systems on voltage profile, system loss, and transmission lines power flow. The IEEE 9 bus system is considered as a standard test system for analysis. The simulation was carried out with the help of ETAP v16.0.0, which is a very convenient tool for the simulation and analysis of the power system. [ABSTRACT FROM AUTHOR]