Yong Sun¹, Haifeng Zhang^1,2, Xiaozhe Song¹, Yifu Zhang^1,2, Song Gao^1,2, Jiayang Zhang^3,*

Energy Engineering, Vol.122, No.5, pp. 1863-1885, 2025, DOI:10.32604/ee.2025.061940 - 25 April 2025

Abstract Aiming at the problems of large fluctuation of output active power and poor control performance in the process of frequency support of an energy-storage-type static-var-generator (ESVG), the adaptive adjustment control method for its active-loop parameters is used to realize the wind-farm frequency support, which has become the current research hotspot. Taking the ESVG with a supercapacitor on the DC side as the research object, the influence trend of the change of virtual rotation inertia and virtual damping coefficient on its virtual angular velocity and power angle is analyzed. Then, the constraint relationship between the equivalent… More >

Wei Chen, Xin Gao^*, Zhanhong Wei, Xusheng Yang, Zhao Li

Energy Engineering, Vol.122, No.2, pp. 805-821, 2025, DOI:10.32604/ee.2025.059779 - 31 January 2025

Abstract This paper deeply introduces a brand-new research method for the synchronous characteristics of DC microgrid bus voltage and an improved synchronous control strategy. This method mainly targets the problem of bus voltage oscillation caused by the bifurcation behavior of DC microgrid converters. Firstly, the article elaborately establishes a mathematical model of a single distributed power source with hierarchical control. On this basis, a small-world network model that can better adapt to the topology structure of DC microgrids is further constructed. Then, a voltage synchronization analysis method based on the main stability function is proposed, and… More >

Zhenshuai Wan^1,2,*, Longwang Yue², Yanfeng Wang², Pu Zhao²

CMES-Computer Modeling in Engineering & Sciences, Vol.141, No.2, pp. 1047-1065, 2024, DOI:10.32604/cmes.2024.053773 - 27 September 2024

Abstract Hydraulic actuators are highly nonlinear when they are subjected to different types of model uncertainties and dynamic disturbances. These unfavorable factors adversely affect the control performance of the hydraulic actuator. Although various control methods have been employed to improve the tracking precision of the dynamic system, optimizing and adjusting control gain to mitigate the hydraulic actuator model uncertainties remains elusive. This study presents an adaptive back-stepping sliding mode controller (ABSMC) to enhance the trajectory tracking precision, where the virtual control law is constructed to replace the position error. The adaptive control theory is introduced in More >

Jiarui Zhang¹, Dan Liu^2,*, Kan Cao², Ping Xiong², Xiaotong Ji³, Yanze Xu¹, Yunfei Mu¹

Energy Engineering, Vol.121, No.8, pp. 2065-2083, 2024, DOI:10.32604/ee.2024.050342 - 19 July 2024

Abstract The system performance of grid-connected photovoltaic (PV) has a serious impact on the grid stability. To improve the control performance and shorten the convergence time, a predefined-time controller based on backstepping technology and dynamic surface control is formulated for the inverter in the grid-connected photovoltaic. The time-varying tuning functions are introduced into state-tracking errors to realize the predefined-time control effect. To address the “computational explosion problem” in the design process of backstepping control, dynamic surface control is adopted to avoid the analytical calculations of virtual control. The disturbances of the PV system are estimated and More >

Feng Zhao, Jinshuo Zhang^*, Xiaoqiang Chen, Ying Wang

Energy Engineering, Vol.121, No.2, pp. 339-358, 2024, DOI:10.32604/ee.2023.043082 - 25 January 2024

Abstract In the DC microgrid, the lack of inertia and damping in power electronic converters results in poor stability of DC bus voltage and low inertia of the DC microgrid during fluctuations in load and photovoltaic power. To address this issue, the application of a virtual synchronous generator (VSG) in grid-connected inverters control is referenced and proposes a control strategy called the analogous virtual synchronous generator (AVSG) control strategy for the interface DC/DC converter of the battery in the microgrid. Besides, a flexible parameter adaptive control method is introduced to further enhance the inertial behavior of… More >

Yunfan Huang¹, Qingquan Lv², Zhenzhen Zhang², Haiying Dong^1,*

Energy Engineering, Vol.120, No.6, pp. 1401-1420, 2023, DOI:10.32604/ee.2023.027365 - 03 April 2023

Abstract The virtual synchronous generator (VSG) can simulate synchronous machine’s operation mechanism in the control link of an energy storage converter, so that an electrochemical energy storage power station has the ability to actively support the power grid, from passive regulation to active support. Since energy storage is an important physical basis for realizing the inertia and damping characteristics in VSG control, energy storage constraints of the physical characteristics on the system control parameters are analyzed to provide a basis for the system parameter tuning. In a classic VSG control, its virtual inertia and damping coefficient… More >

Tianyuan Jia¹, Xiangyong Chen^1,2,*, Xiurong Yao^1,*, Feng Zhao¹, Jianlong Qiu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.134, No.1, pp. 221-239, 2023, DOI:10.32604/cmes.2022.020780 - 24 August 2022

Abstract Fixed-time synchronization (FTS) of delayed memristor-based neural networks (MNNs) with discontinuous activations is studied in this paper. Both continuous and discontinuous activations are considered for MNNs. And the mixed delays which are closer to reality are taken into the system. Besides, two kinds of control schemes are proposed, including feedback and adaptive control strategies. Based on some lemmas, mathematical inequalities and the designed controllers, a few synchronization criteria are acquired. Moreover, the upper bound of settling time (ST) which is independent of the initial values is given. Finally, the feasibility of our theory is attested More >

Qamar Abbas¹, Khalid Mahmood Malik², Abdul Khader Jilani Saudagar^3,*, Muhammad Badruddin Khan³, Mozaherul Hoque Abul Hasanat³, Abdullah AlTameem³, Mohammed AlKhathami³

CMC-Computers, Materials & Continua, Vol.72, No.1, pp. 1229-1250, 2022, DOI:10.32604/cmc.2022.024211 - 24 February 2022

Abstract One of the challenging problems with evolutionary computing algorithms is to maintain the balance between exploration and exploitation capability in order to search global optima. A novel convergence track based adaptive differential evolution (CTbADE) algorithm is presented in this research paper. The crossover rate and mutation probability parameters in a differential evolution algorithm have a significant role in searching global optima. A more diverse population improves the global searching capability and helps to escape from the local optima problem. Tracking the convergence path over time helps enhance the searching speed of a differential evolution algorithm… More >

Ibrahim M. Mehedi^1,2,*, Mohd Heidir Mohd Shah¹ , Soon Xin Ng³ , Abdulah Jeza Aljohani^1,2, Mohammed El-Hajjar³, Muhammad Moinuddin^1,2

CMC-Computers, Materials & Continua, Vol.70, No.3, pp. 4691-4705, 2022, DOI:10.32604/cmc.2022.020954 - 11 October 2021

Abstract

This paper presents the design and implementation of Adaptive Generalized Dynamic Inversion (AGDI) to track the position of a Linear Flexible Joint Cart (LFJC) system along with vibration suppression of the flexible joint. The proposed AGDI control law will be comprised of two control elements. The baseline (continuous) control law is based on principle of conventional GDI approach and is established by prescribing the constraint dynamics of controlled state variables that reflect the control objectives. The control law is realized by inverting the prescribed dynamics using dynamically scaled Moore-Penrose generalized inversion. To boost the robust attributes

… More >

Aiyun Hu¹, Sunli Cong^1,*, Jian Ding², Yao Cheng¹, Enock Mpofu³

Computer Systems Science and Engineering, Vol.38, No.1, pp. 65-77, 2021, DOI:10.32604/csse.2021.016404 - 01 April 2021

Abstract In the fed-batch cultivation of Saccharomyces cerevisiae, excessive glucose addition leads to increased ethanol accumulation, which will reduce the efficiency of glucose utilization and inhibit product synthesis. Insufficient glucose addition limits cell growth. To properly regulate glucose feed, a different evolution algorithm based on self-adaptive control strategy was proposed, consisting of three modules (PID, system identification and parameter optimization). Performance of the proposed and conventional PID controllers was validated and compared in simulated and experimental cultivations. In the simulation, cultivation with the self-adaptive control strategy had a more stable glucose feed rate and concentration, more stable More >