Stochastic configuration network (SCN), as a novel incremental generation model with supervisory mechanism, has an excellent superiority in solving large-scale data regression and classification problems. However, the accuracy of the SCN is affected by the assignation and selection of some network parameters significantly Sparrow search algorithm (SSA) is a new meta-heuristic algorithm that simulates the foraging and anti-predation behavior of sparrow population. In this paper, a stochastic configuration network based on chaotic sparrow search algorithm is first introduced, termed as CSSA-SCN. Firstly, chaotic sparrow search algorithm (CSSA) is designed which mainly utilizes logistic mapping, self-adaptive hyper-parameters, mutation operator to enhance the global optimization capability of SSA; Secondly, as the performance of SCN is related to regularization parameter r and scale factor λ of weights and biases, then CSSA is employed to give better parameters for SCN automatically; Finally, 13 benchmark functions and several datasets are used to evaluate the performance of CSSA and CSSA-SCN respectively. Experimental results demonstrate the feasibility and validity of CSSA-SCN compared with SCN and other contrast algorithms.

A stochastic configuration network based on chaotic sparrow search algorithm

Ant Lion Optimizer (ALO) is a recent novel algorithm developed in the literature that simulates the foraging behavior of a Ant lions. Recently, it has been applied to a huge number of optimization problems. It has many advantages: easy, scalable, flexible, and have a great balance between exploration and exploitation. In this comprehensive study, many publications using ALO have been collected and summarized. Firstly, we introduce an introduction about ALO. Secondly, we categorized the recent versions of ALO into 3 Categories mainly Modified, Hybrid and Multi-Objective. we also introduce the applications in which ALO has been applied such as power, Machine Learning, Image processing problems, Civil Engineering, Medical, etc. The review paper is ended by giving a conclusion of the main ALO foundations and providing some suggestions & possible future directions that can be investigated.

/pdf/ant-lion-optimization-variants-hybrids-and-applications-3dp7pu40yb.pdf

Ant Lion Optimization: Variants, Hybrids, and Applications

Classical wind energy conversion systems are usually passive generators. The generated power does not depend on the grid requirement but entirely on the fluctuant wind condition. A dc-coupled wind/hydrogen/super capacitor hybrid power system is studied in this paper. The purpose of the control system is to coordinate these different sources, particularly their power exchange, in order to make controllable the generated power. As a result, an active wind generator can be built to provide some ancillary services to the grid. The control system should be adapted to integrate the power management strategies. Two power management strategies are presented and compared experimentally. We found that the “source-following” strategy has better performances on the grid power regulation than the “grid-following” strategy.

https://www.jetir.org/papers/JETIR1604051.pdf

Energy Management and Power Control of a Hybrid Active Wind Generator for Distributed Power Generation and Grid Integration

This paper presents a novel contribution of a low complexity control scheme for voltage control of a dynamic voltage restorer (DVR). The scheme proposed utilizes an error-driven proportional-integral-derivative (PID) controller to guarantee better power quality performance in terms of voltage enhancement and stabilization of the buses, energy efficient utilization, and harmonic distortion reduction in a distribution network. This method maintains the load voltage close to or equal to the nominal value in terms of various voltage disturbances such as balanced and unbalanced sag/swell, voltage imbalance, notching, different fault conditions as well as power system harmonic distortion. A grasshopper optimization algorithm (GOA) is used to tune the gain values of the PID controller. In order to validate the effectiveness of the proposed DVR controller, first, a fractional order PID controller was presented and compared with the proposed one. Further, a comparative performance evaluation of four optimization techniques, namely Cuckoo search (CSA), GOA, Flower pollination (FBA), and Grey wolf optimizer (GWO), is presented to compare between the PID and FOPID performance in terms of fault conditions in order to achieve a global minimum error and fast dynamic response of the proposed controller. Second, a comparative analysis of simulation results obtained using the proposed controller and those obtained using an active disturbance rejection controller (ADRC) is presented, and it was found that the performance of the optimal PID is better than the performance of the conventional ADRC. Finally, the effectiveness of the presented DVR with the controller proposed has been assessed by time-domain simulations in the MATLAB/Simulink platform.

An improved approach for robust control of dynamic voltage restorer and power quality enhancement using grasshopper optimization algorithm.

Power quality is a pressing concern and of the utmost importance for advanced and high-tech equipment in particular, whose performance relies heavily on the supply’s quality. Power quality issues like voltage sags/swells, harmonics, interruptions, etc. are defined as any deviations in current, voltage, or frequency that result in end-use equipment damage or failure. Sensitive loads like medical equipment in hospitals and health clinics, schools, prisons, etc. malfunction for the outages and interruptions, thereby causing substantial economic losses. For enhancing power quality, custom power devices (CPDs) are recommended, among which the Dynamic Voltage Restorer (DVR) is considered as the best and cost-effective solution. DVR is a power electronic-based solution to mitigate and compensate voltage sags. This paper provides a thorough discussion and comprehensive review of DVR topologies based on operations, power converters, control methods, and applications. The review compares the state-of-the-art in works of literature, and comparative study on power quality issues, the DVR principle along with its operation modes, the DVR components, the DVR topologies based on energy storage, the DVR topologies based on single-/three-phase power converters, and the DVR topologies based on control units that have different control processing stages. Furthermore, modified and improved configurations of the DVR, as well as its integration with distributed generations, are described. This work serves as a comprehensive and useful reference for those who have an interest in researching DVRs.

https://www.mdpi.com/1996-1073/13/16/4152/pdf

Dynamic Voltage Restorer (DVR): A Comprehensive Review of Topologies, Power Converters, Control Methods, and Modified Configurations

Power quality (PQ) is gaining a great deal of importance as more sensitive loads are introduced into the utility grid. The degradation of product quality, damage of equipment and temporary shutdowns are the general issues associated with PQ problems in industries. Any mal-operation or damage of the industrial sensitive loads results in monetary losses disproportionately higher than the severity of the PQ issues. The evolution of power electronics technology replaced the traditional power quality mitigation methods with the introduction of Custom Power System devices (CUPS). The major power electronic controller based CUPS are DSTATCOM, DVR and UPQC. DVR is a pertinent solution for the economic losses caused by the PQ issues in the industries. Among the CUPS, DVR is the most cost-effective one. In the published literature, only a few papers correspond to the review of DVR technology. In this paper, a systematic review of published literature is conducted and a description is given on the design, standards and challenges in the DVR technology. A detailed survey is conducted on the published Journal of Green Engineering, Vol. 8 4, 519–572. River Publishers doi: 10.13052/jge1904-4720.844 This is an Open Access publication. c © 2018 the Author(s). All rights reserved. 520 V. K. Remya et al. literature to address the various aspects and issues in the DVR system. This paper arrangement gives the working principle, structure, various topologies, compensation techniques, voltage sag detection methods and control methods of the DVR under different sections. The section “Challenges faced by the DVR” included in the manuscript can be useful for the researchers beginning their work in the domain of DVR. The simulation results using the sim power system tool of MATLAB/Simulink software are provided for analysis and comparison.

/pdf/dynamic-voltage-restorer-dvr-a-review-2fns7aen1a.pdf

Dynamic Voltage Restorer (DVR) – A Review

A novel topology of single-phase dynamic voltage restorer (DVR) is proposed to compensate the load voltage during voltage sag and voltage swell events. The semi-Z-source converter is utilised in its inverter operating mode for this proposed topology. The reduction in the number of active switches in the inverter and also in the current conduction path without compromising the output voltage range is the merit of the semi-Z-source inverter-based DVR against the commonly used full-bridge inverter-based DVR. The load voltage contains harmonics within the permissible limits when the compensation is performed by the semi-Z-source inverter-based DVR. The need for the filter circuit is eliminated; hence, the magnitude difference and the phase shift in the inverter output voltage due to the filter circuit are not present in the semi-Z-source inverter-based DVR. The proposed topology is cheap compared to the full-bridge inverter-based DVR topology. The simulations performed in MATLAB/Simulink environment are presented to validate the performance of the proposed topology. A comparison between the semi-Z-source inverter-based DVR and full-bridge inverter-based DVR is presented in this paper. The novel topology of DVR using semi-Z-source inverter is proved to be a better solution to the full-bridge inverter-based DVR.

Single-Phase DVR with Semi-Z-Source Inverter for Power Distribution Network

The major concern in power distribution system is the power quality concerns specifically voltage sag/swell and harmonics. To compensate for such voltage disturbances, an effective device called dynamic voltage restorer (DVR) is utilized in the electric power distribution system. Accordingly, in this paper, the DVR is designed to shield the sensitive load from source-side voltage disturbances under nonlinear load conditions. Further, in the proposed work, an ant lion optimizer-optimized artificial neural network (ALO-ANN) is used to control DVR, thus compensating the balanced and the unbalanced voltage sag/swell and distortions in the load-side voltage. Simulation results using MATLAB/Simulink software are analysed to confirm the efficiency of the suggested ALO-ANN regulator scheme of DVR system at critical loads by comparing with the existing PSO (particle swarm optimization)-centred control scheme.

ALO-optimized artificial neural network-controlled dynamic voltage restorer for compensation of voltage issues in distribution system

Dynamic Voltage Restorers are identified to be cost effective solution for protecting sensitive loads from voltage related power quality issues. The extension of cost reduction and efficiency can be improved by eliminating the injection transformer. This paper discusses a transformer-less dynamic voltage restorer based on three-single phase Voltage Source Inverters(VSI). Since the DVR does not have an injection transformer, it has lower loss, lower cost and it is less bulky. The DVR control is implemented using Synchronous Reference Frame(SRF)theory. Estimation of the reference load voltage is carried out using unit vectors. The simulation results carried out in MATLAB shows the effectiveness of the DVR in compensating the voltage sag.

Transformerless Dynamic Voltage Restorer for voltage sag mitigation

In this paper operation performance of an high-frequency (HF) link ac/ac converter is demonstrated using computer aided simulation package PSCAD/EMTDC. The converter consists of input filter, input matrix converter, HF transformer, and output matrix converter. The proposed configuration permits flexibility in the choice of voltage levels and frequency in the system without the penalty of bulky magnetic components. The proposed approach achieve high voltage transfer ratio, HF galvanic isolation of the input source from the output utility, higher power density by introducing a HF transformer in between the two stages of the converter. It is capable of having bidirectional power flow, achieve lower harmonic distortion on both input and output sides with proper filter design and controllable input displacement power factor. It also provides fast response, high efficiency, and free from acoustic noise. Comprehensive results are presented to assess the performance of the converter. Several features like voltage sag compensation, instantaneous voltage regulation, and power factor correction can be combined to this converter. This kind of converter laid the base for regulated ac power supplies and electronic transformers.

V. Ansal

Papers

Dynamic Voltage Restorer (DVR) – A Review

Single-Phase DVR with Semi-Z-Source Inverter for Power Distribution Network

ALO-optimized artificial neural network-controlled dynamic voltage restorer for compensation of voltage issues in distribution system

Transformerless Dynamic Voltage Restorer for voltage sag mitigation

Performance study of high frequency link AC-AC converter