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17 pages, 8391 KiB

Open AccessArticle

Enhanced Control of Back-to-Back Converters in Wind Energy Conversion Systems Using Two-Degree-of-Freedom (2DOF) PI Controllers

by Hussain A. Hussain

Electronics 2023, 12(20), 4221; https://doi.org/10.3390/electronics12204221 - 12 Oct 2023

Viewed by 824

Abstract

The performance of a full-scale wind energy conversion system is dependent on the control system of the back-to-back power electronics converter. Different controllers have been proposed in the literature, many of which are variations of a generalized two-degrees-of-freedom (2DOF) PI controller. This paper [...] Read more.

The performance of a full-scale wind energy conversion system is dependent on the control system of the back-to-back power electronics converter. Different controllers have been proposed in the literature, many of which are variations of a generalized two-degrees-of-freedom (2DOF) PI controller. This paper presents a design method for the parameters of a 2DOF PI controller for the stator current, generator speed, grid current, and DC bus voltage control. The controller can be designed using a general independent zero and pole placement method. The proposed and conventional methods are analyzed based on their ability to track references, reject disturbances, and their sensitivity to noise. A tuning approach is proposed to enhance the controller’s bandwidth without sacrificing noise sensitivity or disturbance rejection capability. The conventional methods are shown to be special versions of the proposed design. Simulation results demonstrate the effectiveness of the proposed design. Full article

(This article belongs to the Special Issue Power Electronics for Renewable Energy Systems: Latest Advances and Prospects)

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20 pages, 9113 KiB

Open AccessFeature PaperArticle

A Novel Fuzzy-Logic-Based Control Strategy for Power Smoothing in High-Wind Penetrated Power Systems and Its Validation in a Microgrid Lab

by Danny Ochoa, Sergio Martinez and Paul Arévalo

Electronics 2023, 12(7), 1721; https://doi.org/10.3390/electronics12071721 - 04 Apr 2023

Cited by 4 | Viewed by 1404

Abstract

Wind power generation has undergone significant development in recent decades due to its environmental advantages and its economic competitiveness. However, its increasing level of penetration is not exempt from drawbacks, such as those derived from the fluctuating nature of the wind. To reduce [...] Read more.

Wind power generation has undergone significant development in recent decades due to its environmental advantages and its economic competitiveness. However, its increasing level of penetration is not exempt from drawbacks, such as those derived from the fluctuating nature of the wind. To reduce its negative incidence on grid power quality and stability, different techniques have been developed, such as those based on power smoothing. In these techniques, there is a research gap on the adjustment of the time constant that adapts to the needs of the smoothing, avoiding uncertain results, computational efforts and delays in the response of the control. This paper addresses the problem, proposing a novel method for power smoothing in a wind turbine by using a fuzzy-logic-based supercapacitor storage system and time-constant fitting, with a first-order adaptive transfer function. The method considers as input variables the active power generated by the wind turbine and the state of charge of the supercapacitor, both sampled simultaneously. After a computation process, the proposal generates active power set-point values that the supercapacitor must produce to compensate for the intermittency of the wind, seen from the point of connection to the grid. The results were validated experimentally with comprehensive laboratory tests. Full article

(This article belongs to the Special Issue Power Electronics for Renewable Energy Systems: Latest Advances and Prospects)

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13 pages, 4286 KiB

Open AccessArticle

A Novel Electrolytic-Free Quasi-Z-Source Ćuk LED Driver for Automotive Application

by Lei Wang and Wei Hu

Electronics 2023, 12(4), 997; https://doi.org/10.3390/electronics12040997 - 16 Feb 2023

Viewed by 816

Abstract

This paper proposes a novel electrolytic-free quasi-Z-Source Ćuk LED driver for automotive applications. Compared to the traditional Ćuk converter, the first merit of the novel converter is higher gain, which makes it apt to switch between multiple applications. Secondly, the proposed converter combines [...] Read more.

This paper proposes a novel electrolytic-free quasi-Z-Source Ćuk LED driver for automotive applications. Compared to the traditional Ćuk converter, the first merit of the novel converter is higher gain, which makes it apt to switch between multiple applications. Secondly, the proposed converter combines the inherent characteristics of LED load to operate in a wide range in Continuous Conduction Mode (CCM), so the inductors can assist in energy storage, and only small capacitance is required. Thirdly, inductors can be integrated and use only one core, and capacitors are electrolytic-free, which will benefit integration and long life. All merits are important to automotive application. Detailed analysis and design steps are presented. Then, with the help of the simulation software Saber, several key parts of the converter are simulated. Finally, a prototype controlled by the micro control unit stm32f103c8t6 is built, and the feasibility is verified by the experiment results. Full article

(This article belongs to the Special Issue Power Electronics for Renewable Energy Systems: Latest Advances and Prospects)

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16 pages, 8744 KiB

Open AccessArticle

Modeling and Investigation of Rear-Passivated Ultrathin CIGS Solar Cell

by Nour El I. Boukortt, Salvatore Patanè and Mabrouk Adouane

Electronics 2023, 12(3), 758; https://doi.org/10.3390/electronics12030758 - 02 Feb 2023

Cited by 1 | Viewed by 1262

Abstract

In this paper, we use numerical simulations to investigate ultrathin Cu (In_1−xGa_x) Se₂ solar cells. In the first part, we focus on the cell configuration in which the PV parameters fit and match the fabricated cell characteristics. Our [...] Read more.

In this paper, we use numerical simulations to investigate ultrathin Cu (In_1−xGa_x) Se₂ solar cells. In the first part, we focus on the cell configuration in which the PV parameters fit and match the fabricated cell characteristics. Our goal is to investigate the impact of different loss mechanisms, such as interface trap density (D_it) and absorber trap density (N_t), in different cell pitch sizes on cell performances. D_it defines the number of carrier traps at CIGS/Al₂O₃ interfaces to recombine with photogenerated carriers. N_t defines the number of carrier traps in the absorber layer. Recombination through traps has been found to be the primary loss process in the investigated cell. Additional numerical simulations reveal appreciable gains in cell performance for various cell pitch sizes, absorber doping densities, Ga content, and graded bandgap under AM1.5 illumination. Research during the recent decade has clarified that the most promising strategy to achieve maximum efficiency consists of the so-called tandem configuration. Therefore, we here propose a u-CIGS/PERT silicon device employing, as a top cell, a u-CIGS cell optimized to take into account the above procedure. The results of these simulations provide insights into the optimization of ultrathin-film CIGS solar cells. Full article

(This article belongs to the Special Issue Power Electronics for Renewable Energy Systems: Latest Advances and Prospects)

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25 pages, 983 KiB

Open AccessArticle

Improved-Odd-Even-Prime Reconfiguration to Enhance the Output Power of Rectangular Photovoltaic Array under Partial Shading Conditions

by Dileep Katiki, Chandrasekhar Yammani and Surender Reddy Salkuti

Electronics 2023, 12(2), 427; https://doi.org/10.3390/electronics12020427 - 13 Jan 2023

Cited by 4 | Viewed by 1346

Abstract

The output power of a PV (photovoltaic) array decreases due to the partial shading condition (PSC). If one or more PV modules receives less irradiance compared to other PV modules in a PV array then it is called PSC. To enhance the output [...] Read more.

The output power of a PV (photovoltaic) array decreases due to the partial shading condition (PSC). If one or more PV modules receives less irradiance compared to other PV modules in a PV array then it is called PSC. To enhance the output power of PV array under PSC, Sudoku, and Optimal Sudoku Reconfiguration techniques are available in the literature for perfect squared PV arrays, such as 4 × 4, 9 × 9, and 16 × 16. Odd–Even and Odd–Even–Prime reconfigurations are available for rectangular PV arrays. To enhance the output power of rectangular PV array further, this paper proposed a new reconfiguration technique called Improved Odd–Even–Prime reconfiguration. To validate the proposed method, two PV arrays 9 × 9 and 8 × 9 have been implemented. Full article

(This article belongs to the Special Issue Power Electronics for Renewable Energy Systems: Latest Advances and Prospects)

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12 pages, 3401 KiB

Open AccessArticle

Graded Bandgap Ultrathin CIGS Solar Cells

by Nour El I. Boukortt, Salvatore Patanè, Baghdad Hadri and Giovanni Crupi

Electronics 2023, 12(2), 393; https://doi.org/10.3390/electronics12020393 - 12 Jan 2023

Cited by 3 | Viewed by 1864

Abstract

In this paper, we physically modeled passivated ultrathin Cu (In_1−xGa_x) Se₂ solar cells with different bandgap grading configurations. Firstly, we have designed the cell architecture according to the fabricated model. The novelty in this work is the modeling [...] Read more.

In this paper, we physically modeled passivated ultrathin Cu (In_1−xGa_x) Se₂ solar cells with different bandgap grading configurations. Firstly, we have designed the cell architecture according to the fabricated model. The novelty in this work is the modeling of passivated u-CIGS solar cells with different bandgap grading profile configurations in order to achieve high efficiency with a thickness of 500 nm. A significant influence on device performance has been observed while changing absorber doping density, electron affinity, and operating temperature (range of 10–70 °C) for the investigated samples. ZnS has been used as a buffer layer to replace the conventional CdS material in order to improve cell efficiency. The impact of the buffer doping density and electron affinity on u-CIGS cell performance is explored. The simulation results show that a high bandgap at the front and rear sides with an acceptor density of 2 × 10¹⁶ provide the best electrical cell parameters: J_sc of 31.53 mA/cm², V_oc of 742.78 mV, FF of 77.50%, η of 18.15%. Our findings can be considered guidelines for new single and/or tandem cell optimization to achieve high efficiency. Full article

(This article belongs to the Special Issue Power Electronics for Renewable Energy Systems: Latest Advances and Prospects)

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26 pages, 13116 KiB

Open AccessArticle

An Integrated Buck and Half-Bridge High Step-Down Converter

by Kuo-Ching Tseng, Van-Tsai Liu, Rui-Yu Chen and Ren-Hsiang Hsieh

Electronics 2022, 11(17), 2666; https://doi.org/10.3390/electronics11172666 - 25 Aug 2022

Viewed by 1403

Abstract

In this paper, an integrated buck and asymmetrical half-bridge (IBAHB) high step-down converter utilizing a single-stage driving design for highly efficient energy conversion is proposed. The proposed converter is able to instantly and synchronously transfer energy from input to output within one conversion [...] Read more.

In this paper, an integrated buck and asymmetrical half-bridge (IBAHB) high step-down converter utilizing a single-stage driving design for highly efficient energy conversion is proposed. The proposed converter is able to instantly and synchronously transfer energy from input to output within one conversion period. The advantages of high step-down conversion, lower voltage stress and fewer semiconductor elements verify the feasibility of this proposed topology. The turns ratio of the transformer can be reduced to increase the coupling rate, which decreases the leakage inductance. The proposed integrated topology utilizes the single-stage energy transfer control algorithm to verify that the proposed experimental circuit has a full-load efficiency. This development will achieve the market’s demand for high-buck converters and other related products and the competitive advantage of growing with the trend. Full article

(This article belongs to the Special Issue Power Electronics for Renewable Energy Systems: Latest Advances and Prospects)

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Review

Jump to: Research

21 pages, 1301 KiB

Open AccessReview

Overview of Virtual Synchronous Generators: Existing Projects, Challenges, and Future Trends

by Mohamed Abuagreb, Mohammed F. Allehyani and Brian K. Johnson

Electronics 2022, 11(18), 2843; https://doi.org/10.3390/electronics11182843 - 08 Sep 2022

Cited by 17 | Viewed by 2601

Abstract

The rapid growth in renewable energy-based distributed generation has raised serious concerns about the grid’s stability. Due to the intrinsic rotor inertia and damping feature and the voltage (reactive power) control ability, traditional bulk power plants, which are dominated by synchronous generators (SG), [...] Read more.

The rapid growth in renewable energy-based distributed generation has raised serious concerns about the grid’s stability. Due to the intrinsic rotor inertia and damping feature and the voltage (reactive power) control ability, traditional bulk power plants, which are dominated by synchronous generators (SG), can readily sustain system instability. However, converter-based renewable energy sources possess unique properties, such as stochastic real and reactive power output response, low output impedance, and little or no inertia and damping properties, leading to frequency and voltage disturbance in the grid. To overcome these issues, the concept of virtual synchronous generators (VSG) is introduced, which aims to replicate some of the characteristics of the traditional synchronous generators using a converter control technique to supply more inertia virtually. This paper reviews the fundamentals, different topologies, and a detailed VSG structure. Moreover, a VSG-based frequency control scheme is emphasized, and the paper focuses on the different topologies of VSGs in the microgrid frequency regulation task. Then, the characteristics of the control systems and applications of the virtual synchronous generators are described. Finally, the relevant critical issues and technical research challenges are presented, and future trends related to this subject are highlighted. Full article

(This article belongs to the Special Issue Power Electronics for Renewable Energy Systems: Latest Advances and Prospects)

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