Table of Contents

Open Access

ISSN 2690-1692

Journal of Energy and Power Technology , Volume 6 , Issue 1 (2024)

Pages: 193

Published: March 2024

(This book is a printed edition that was published in Journal of Energy and Power Technology)

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Cover Story: In this article, a novel nonlinear optimal control method is developed for the dynamic model a wave energy conversion unit that includes a Permanent Magnet Linear Synchronous Generator (PMLSG) serially connected to a three-phase AC/DC Voltage Source Converter (VSC). The dynamic model of the integrated PMLSG-VSC-based power unit is presented in state-space form, and differential flatness properties are proven about it. Differential flatness is also an implicit proof of the system’s controllability and its input-output linearizability. Indeed, through successive differentiations of the power unit’s flat outputs, this system is transformed into the input-output linearized form, and a stabilizing feedback controller is developed about it using the eigenvalues assignment technique. Applying the nonlinear optimal control schemes mentioned above can help avoid the complicated and elongated state-space model transformations characteristic of this control method.
In the article’s nonlinear optimal control approach, the dynamic model of the PMSLG-VSC-based wave energy conversion system undergoes first approximate linearization through Taylor series expansion. This approximate linearization process occurs at each sampling instance around a time-varying operating point defined by the present value of the system’s state vector and the last sampled value of the control inputs vector. The linearization primarily relies on computing the system’s Jacobian matrices and updating them at each sampling interval. The modeling error arising from the truncation of higher-order terms in the Taylor series is regarded as a perturbation that is asymptotically compensated for by the robustness of the control algorithm.
A stabilizing H-infinity feedback controller is designed for the approximately linearized PMSLG-VSC-based wave energy conversion unit model. This controller solves the optimal control problem for the wave energy conversion system under model uncertainty and external perturbations. It represents a min-max differential game between (i) the control inputs, which try to minimize a quadratic function of the state vector’s tracking error, and (ii) the model uncertainty or perturbation terms, which try to maximize this cost function. To compute the controller’s gains, an algebraic Riccati equation is solved repetitively at each time step of the control method. The global stability properties of this control scheme are demonstrated through Lyapunov analysis. Initially, it is established that the control loop satisfies the H-infinity tracking performance criterion, indicating significant robustness to model uncertainties and external perturbations.View this paper.

Volume 6,Issue 1

Open Access Original Research

Wind Farm Layout Optimization Subject to Cable Cost, Hub Height, and a Feasible 3D Gaussian Wake Model Implementation

Received: 06 February 2024;  Published: 15 March 2024;  doi: 10.21926/jept.2401008


We address the Wind Farm Layout Optimization (WFLO) problem and tackle the optimal placement of several turbines within a specific (wind farm) area by incorporating additional aspects of an economically driven target function. With this, we contribute three refinements for WFLO research: First, while many research contributions optimize the turbines’ locations subject to maximum energy production or energy efficiency, we instead pursue a strategy of maximizing a profit objective. This enables us [...]

Open Access Review

A Review of North American Prospects for Power and Hot-Water Generation with Thermal Energy

Received: 20 November 2023;  Published: 21 February 2024;  doi: 10.21926/jept.2401007


This article outlines an innovative approach to explore thermal energy extraction for power generation or industrial hot water applications. Unlike traditional steady-state models, this approach embraces time-variant scenarios, explicitly incorporating a cyclical fluid circulation strategy to maintain a stable surface fluid temperature or power output. By introducing an increasing and decreasing stepwise rate sequence and an intermittent circulation strategy, the method aims to optim [...]

Open Access Original Research

Nonlinear Optimal Control for a PMLSG-VSC Wave Energy Conversion Unit

Received: 16 September 2023;  Published: 21 February 2024;  doi: 10.21926/jept.2401006


This article aims to treat the nonlinear control problem for the complex dynamics of a wave energy unit (WEC) that consists of a Permanent Magnet Linear Synchronous Generator (PMLSG) and a Voltage Source Converter (VSC). The article has developed a globally stable nonlinear optimal control method for this wave power generation unit. The new method avoids complicated state-space model transformations and minimizes the energy dispersion by the control loop. A novel nonlinear optimal control method [...]

Open Access Review

Floating Oscillating Water Column Wave Energy Converters: A Review of Developments

Received: 09 December 2023;  Published: 07 February 2024;  doi: 10.21926/jept.2401005


The main challenge in designing offshore renewable energy structures is to ensure their structural integrity on a life cycle basis while operating in harsh environments and, in parallel, being financially competitive and environmentally friendly concerning other types of energy systems. The Oscillating Water Column (OWC) converters are among the first energy converters to be developed and deployed into the sea due to their relative simplicity of operation and relatively small number of moving pa [...]

Open Access Research Article

Monitoring Energy-Loss-Driven-Cost by Using Earned Value Simulation in Complex Systems

Received: 24 July 2023;  Published: 06 February 2024;  doi: 10.21926/jept.2401004


The economic impact of energy loss stemming from end-user electricity consumption is a significant concern, with historical trends revealing escalating costs. Effectively managing both peak and off-peak demands remains a formidable challenge due to the unpredictable nature of consumer behaviors, leading to energy wastage. This study delves into the nexus of demand uncertainty, financial repercussions, and potential strategies to mitigate energy losses in the evolving landscape of electricity con [...]

Open Access Original Research

LFO Damping Enhancement in Multimachine Network Using African Vulture Optimization Algorithm

Received: 20 June 2023;  Published: 30 January 2024;  doi: 10.21926/jept.2401003


The prolonged presence of low-frequency oscillation (LFO) in power system networks (PSN) poses a significant threat to their stability. Hence, engineers and researchers have continuously developed effective strategies to mitigate the issue and enhance the stability of the PSN. This article proposes a new approach using the African Vultures Optimization Algorithm (AVOA) to design robust Power System Stabilizers (PSS) and enhance the LFO damping in multi-machine networks. The damping ratio-based o [...]

Open Access Original Research

Proposal for the Sustainable Electrification of a Primary Healthcare Centre (PHC) Facility in Nigeria

Received: 06 August 2023;  Published: 24 January 2024;  doi: 10.21926/jept.2401002


Energy is a prerequisite to running health facilities and is, therefore, key to the success of the service. Karshi primary healthcare centre (PHC) facility is confronted with an unreliable power supply that leads to a high cost of generating power from diesel to operate its equipment. This facility needs a sustainable and reliable electricity supply and therefore a change in their energy system to enable it improve its quality of healthcare delivery services. A solar energy-based electricity gen [...]

Open Access Editorial

Acknowledgment to Reviewers of Journal of Energy and Power Technology in 2023

Received: 04 January 2024;  Published: 05 January 2024;  doi: 10.21926/jept.2401001


The editors of Journal of Energy and Power Technology would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2023. We greatly appreciate the contribution of expert reviewers, which is crucial to the journal's editorial process. We aim to recognize reviewer contributions through several mechanisms, of which the annual publication of reviewer names is one. Reviewers can download a certificate of recognition directly from our submi [...]