Nonlinear characterization of magnetorheological elastomer-based smart device for structural seismic mitigation
- Authors: Yu, Yang , Hoshyar, Azadeh , Li, Huan , Zhang, Guang , Wang, Weiqiang
- Date: 2021
- Type: Text , Journal article
- Relation: International Journal of Smart and Nano Materials Vol. 12, no. 4 (2021), p. 390-428
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- Description: Magnetorheological elastomer (MRE) has been demonstrated to be effective in structural vibration control because of controllable stiffness and damping properties with the effect of external magnetic fields. To achieve a high performance of MRE device-based vibration control, a robust and accurate model is necessary to describe nonlinear dynamics of MRE device. This article aims at realising this target via nonlinear modeling of an innovative MRE device, i.e. MRE vibration isolator. First, the field-dependent properties of MRE isolator were analysed based on experimental data of the isolator in various dynamic tests. Then, a phenomenal model was developed to account for these unique characteristics of MRE-based device. Moreover, an improved PSO algorithm was designed to estimate model parameters. Based on identification results, a generalised model was proposed to clarify the field-dependent properties of the isolator due to varied currents, which was then validated by random and earthquake-excited test data. Based on the proposed model, a frequency control strategy was designed for semi-active control of MRE devices-incorporated smart structure for vibration suppression. Finally, using a three-storey frame model and four benchmark earthquakes, a numerical study was conducted to validate the performance of control strategy based on the generalised current-dependent model with satisfactory results. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Sizing HESS as inertial and primary frequency reserve in low inertia power system
- Authors: Akram, Umer , Mithulananthan, N. , Shah, Rakibuzzaman , Pourmousavi, S. Ali
- Date: 2021
- Type: Text , Journal article
- Relation: IET renewable power generation Vol. 15, no. 1 (2021), p. 99-113
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- Description: Energy storage systems are recognised as the potential solution to alleviate the impacts of reduced inertia and intermittency in power systems due to the integration of renewable energy sources. Several energy storage technologies are available in the market with diverse power and energy characteristics, operational limitations, and costs. Besides, frequency regulations in power systems have different requirements, for example, inertial response requires high power for a short period while primary frequency regulation requires steady power for a longer time. Thus, it is crucial to find out the optimum sizes and types of storage technologies for these services. In this paper, a methodology for sizing fast responsive energy storage technologies for inertial response, primary frequency regulation, and both inertial response and primary frequency regulation is developed. The sizing of storage systems for inertial response, primary frequency regulation, and both inertial response and primary frequency regulation is done separately. The sizing of storage for inertial response is done in two steps. A region reduction iterative algorithm is proposed to estimate the storage size for inertial response. The sizing of the storage system for primary frequency regulation is done analytically. The sizing methodology incorporates the frequency dynamics of storage, converters, and other associated controls that affect the frequency response. Moreover, an economic analysis is carried out to find the optimum combination of storage technologies for inertial response, primary frequency regulation, and both inertial response and primary frequency regulation services. The accuracy of the proposed sizing method has been compared with the metaheuristic algorithm based technique. The effectiveness of the proposed method is also compared with those in the literature. Simulation results show that the proposed method outperforms the existing methods in the literature. Finally, the non‐linear simulations revealed the validity of the optimal solutions.
Control of a microgrid using robust data-driven-based controllers of distributed electric vehicles
- Authors: Khemmook, Panya , Prompinit, Krisada , Surinkaew, Tossaporn
- Date: 2022
- Type: Text , Journal article
- Relation: Electric Power Systems Research Vol. 213, no. (2022), p.
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- Description: Current advancements in power electronic converters have paved a way to shift the attention from the traditional internal combustion engine to electric vehicles (EVs). In previous research works, the EVs are normally represented by an aggregate model or a first order transfer function, and they are mostly used for the frequency regulation in microgrids (MGs). These may not be valid assumptions since the EVs consist of various distributed units and power electronic converters. To make it more practical, distributed EV models with a function of MG voltage control should be further considered. This paper proposes an approach for MG voltage and frequency regulations using data-driven-based controllers for distributed EVs. Without requiring any MG parameters, information of uncertainties with respect to operation changes are monitored such that major stability indices, i.e., damping and robustness, can be automatically calculated. Considering these indices, the adaptive control technique is applied to design the controllers. The proposed adaptive data-driven-based controller is compared to a controller designed by considering dynamics of full-converter models. Simulation results are validated in a MG with renewable energy sources and distributed EVs under various operating points and uncertainties. © 2022 Elsevier B.V.
A unified model predictive voltage and current control for microgrids with distributed fuzzy cooperative secondary control
- Authors: Shan, Yinghao , Hu, Jiefeng , Chan, Ka , Islam, Syed
- Date: 2021
- Type: Text , Journal article
- Relation: IEEE Transactions on Industrial Informatics Vol. 17, no. 12 (DEC 2021), p. 8024-8034
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- Description: A microgrid formed by a cluster of parallel distributed generation (DG) units is capable of operating in either islanded mode or grid-connected mode. Traditionally, by using model predictive control algorithms, these two operation modes can be achieved with two separate and different cost functions, which brings in control complexity and hence, compromises system reliability. In this article, a unified model predictive voltage and current control strategy is proposed for both islanded and grid-connected operations and their smooth transition. The cost function is kept unified with voltage and current taken into account without altering the control architecture. It can be used for high-quality voltage supply at the primary control level and for bidirectional power flow at the tertiary control level. In addition, by only using DGs' own and neighboring information, a distributed fuzzy cooperative algorithm is developed at the secondary layer to mitigate the voltage and frequency deviations inherent from the power droop. The fuzzy controller can optimize the secondary control coefficients for further voltage quality improvement. Comprehensive tests under various scenarios demonstrate the merits of the proposed control strategy over traditional methods.
Frequency-constrained unit-commitment using analytical solutions for system frequency responses considering generator contingencies
- Authors: Rabbanifar, Payam , Amjady, Nima
- Date: 2020
- Type: Text , Journal article
- Relation: IET generation, transmission & distribution Vol. 14, no. 17 (2020), p. 3548-3560
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- Description: The frequency responses of a power system following a generator outage are closely related to the commitment states of generators, which describe the droop and inertial characteristics and system pre-contingency power dispatch. This study presents a new model to estimate the transient and steady state frequency responses of two-area power systems at any moment following the loss of an online generator. In the proposed model, the deviations of tie-flow, area frequencies and rate of change of area frequencies as well as the extreme values of these functions and their associated time of occurrence following the outage of a generation unit are derived as modified analytical functions. A new approach is also proposed to linearise the modified extreme deviations based on pseudo-Boolean function theorem. In addition, a frequency-constrained unit commitment model with modified frequency-dependent constraints incorporating primary frequency regulation reserve is presented as a mixed-integer linear programming problem. The results indicate that the proposed method gives acceptable approximations for post-contingency responses and can ensure power system security from frequency viewpoint.