Submit to Applied Sciences Review for Applied Sciences Propose a Special Issue

Journal Browser

Advancing Grid-Connected Renewable Generation Systems

Special Issue Editors
Special Issue Information
Keywords
Published Papers

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Energy Science and Technology".

Deadline for manuscript submissions: closed (10 December 2016) | Viewed by 135335

Share This Special Issue

Special Issue Editors

Prof. Dr. Frede Blaabjerg

E-Mail Website
Guest Editor

Department of Energy Technology, Aalborg University, 9220 Aalborg, Denmark
Interests: power electronics and its applications in motor drives; wind turbines; PV systems; harmonics; reliability of power electronic systems
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Yongheng Yang

E-Mail Website
Guest Editor

College of Electrical Engineering, Zhejiang University, Zheda Rd. 38, Hangzhou 310027, China
Interests: power converter control; grid integration of renewable energy; photovoltaic power systems; reliability in power electronics and systems
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Renewables are evolving into an essential component for today’s energy paradigm, which has been undergoing significant shifts over the past few decades—from fossil fuels to renewables, from centralized to decentralized architectures, and from sole to miscellaneous energy resources. In this energy evolution, power electronics technology underpinned by advanced control strategies plays an enabling role in the integration and advancements of renewables, like wind turbine, photovoltaics, fuel cells, and other emerging energy systems. Tremendous application-driven power converters and control techniques for grid-connected renewables have been developed and more are coming into market to secure an efficient and reliable renewable power generation. Stringent demands from both utility operators and consumers have also been (are being) imposed on. This Special Issue, thus, serves to address present challenging issues with the integration of renewable energies in a sustainable and resilient power system. Topics within, but not limited to, grid-connected renewable energy systems are invited.

Prof. Dr. Frede Blaabjerg
Prof. Dr. Yongheng Yang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Renewable energy conversion
Power electronics converter topologies and control for grid-connected renewables
Energy policies
Wind power generation (onshore and offshore)
Photovoltaic power systems (PV, concentrator PV, concentrated solar power plants)
Fuel cell systems
Advanced control for grid-connected renewables
Emerging renewable energy technology
Wide-bandgap power semiconductor applications in renewable energy systems

Published Papers (14 papers)

Download All Papers

Editorial

Jump to: Research, Review

146 KiB

Open AccessEditorial

Special Issue on Advancing Grid-Connected Renewable Generation Systems

by Frede Blaabjerg and Yongheng Yang

Appl. Sci. 2017, 7(6), 577; https://doi.org/10.3390/app7060577 - 03 Jun 2017

Cited by 1 | Viewed by 5016

Abstract

Renewables are heavily involved in power generation, as an essential component for today’s energy paradigm. Energy structure—both national and international—has been undergoing significant changes over the past few decades.[...] Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

Research

Jump to: Editorial, Review

3565 KiB

Open AccessArticle

Zero-Voltage Ride-Through Capability of Single-Phase Grid-Connected Photovoltaic Systems

by Zhen Zhang, Yongheng Yang, Ruiqing Ma and Frede Blaabjerg

Appl. Sci. 2017, 7(4), 315; https://doi.org/10.3390/app7040315 - 24 Mar 2017

Cited by 24 | Viewed by 8128

Abstract

Distributed renewable energy systems play an increasing role in today’s energy paradigm. Thus, intensive research activities have been centered on improving the performance of renewable energy systems, including photovoltaic (PV) systems, which should be of multiple-functionality. That is, the PV systems should be more intelligent in the consideration of grid stability, reliability, and fault protection. Therefore, in this paper, the performance of single-phase grid-connected PV systems under an extreme grid fault (i.e., when the grid voltage dips to zero) is explored. It has been revealed that combining a fast and accurate synchronization mechanism with appropriate control strategies for the zero-voltage ride-through (ZVRT) operation is mandatory. Accordingly, the representative synchronization techniques (i.e., the phase-locked loop (PLL) methods) in the ZVRT operation are compared in terms of detection precision and dynamic response. It shows that the second-order generalized integrator (SOGI-PLL) is a promising solution for single-phase systems in the case of fault ride-through. A control strategy by modifying the SOGI-PLL scheme is then introduced to single-phase grid-connected PV systems for ZVRT operation. Simulations are performed to verify the discussions. The results have demonstrated that the proposed method can help single-phase PV systems to temporarily ride through zero-voltage faults with good dynamics. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

► Show Figures

Figure 1

7271 KiB

Open AccessArticle

Overload Control in Smart Transformer-Fed Grid

by Giovanni De Carne, Zhixiang Zou, Giampaolo Buticchi, Marco Liserre and Costas Vournas

Appl. Sci. 2017, 7(2), 208; https://doi.org/10.3390/app7020208 - 20 Feb 2017

Cited by 12 | Viewed by 6141

Abstract

Renewable energy resources and new loads—such as electric vehicles—challenge grid management. Among several scenarios, the smart transformer represents a solution for simultaneously managing low- and medium-voltage grids, providing ancillary services to the distribution grid. However, unlike conventional transformers, the smart transformer has a very limited overload capability, because the junction temperature—which must always be below its maximum limit—is characterized by a short time constant. In this work, an overload control for smart transformer by means of voltage and frequency variations has been proposed and veriﬁed by means of simulations and experiments. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

► Show Figures

Figure 1

5850 KiB

Open AccessArticle

Development of Probabilistic Reliability Models of Photovoltaic System Topologies for System Adequacy Evaluation

by Ahmad Alferidi and Rajesh Karki

Appl. Sci. 2017, 7(2), 176; https://doi.org/10.3390/app7020176 - 14 Feb 2017

Cited by 28 | Viewed by 5125

Abstract

The contribution of solar power in electric power systems has been increasing rapidly due to its environmentally friendly nature. Photovoltaic (PV) systems contain solar cell panels, power electronic converters, high power switching and often transformers. These components collectively play an important role in shaping the reliability of PV systems. Moreover, the power output of PV systems is variable, so it cannot be controlled as easily as conventional generation due to the unpredictable nature of weather conditions. Therefore, solar power has a different influence on generating system reliability compared to conventional power sources. Recently, different PV system designs have been constructed to maximize the output power of PV systems. These different designs are commonly adopted based on the scale of a PV system. Large-scale grid-connected PV systems are generally connected in a centralized or a string structure. Central and string PV schemes are different in terms of connecting the inverter to PV arrays. Micro-inverter systems are recognized as a third PV system topology. It is therefore important to evaluate the reliability contribution of PV systems under these topologies. This work utilizes a probabilistic technique to develop a power output model for a PV generation system. A reliability model is then developed for a PV integrated power system in order to assess the reliability and energy contribution of the solar system to meet overall system demand. The developed model is applied to a small isolated power unit to evaluate system adequacy and capacity level of a PV system considering the three topologies. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

► Show Figures

Figure 1

2764 KiB

Open AccessArticle

Modeling and Simulation of a Wave Energy Converter INWAVE

by Seung Kwan Song, Yong Jun Sung and Jin Bae Park

Appl. Sci. 2017, 7(1), 99; https://doi.org/10.3390/app7010099 - 19 Jan 2017

Cited by 6 | Viewed by 6447

Abstract

INGINE Inc. developed its own wave energy converter (WEC) named INWAVE and has currently installed three prototype modules in Jeju Island, Korea. This device is an on-shore-type WEC that consists of a buoy, pulleys fixed to the sea-floor and a power take off module (PTO). Three ropes are moored tightly on the bottom of the buoy and connected to the PTO via the pulleys, which are moving back and forth according to the motion of the buoy. Since the device can harness wave energy from all six degrees of movement of the buoy, it is possible to extract energy efficiently even under low energy density conditions provided in the coastal areas. In the PTO module, the ratchet gears convert the reciprocating movement of the rope drum into a uni-directional rotation and determine the transmission of power from the relation of the angular velocities between the rope drum and the generator. In this process, the discontinuity of the power transmission occurs and causes the modeling divergence. Therefore, we introduce the concept of the virtual torsion spring in order to prevent the impact error in the ratchet gear module, thereby completing the PTO modeling. In this paper, we deal with dynamic analysis in the time domain, based on Newtonian mechanics and linear wave theory. We derive the combined dynamics of the buoy and PTO modules via geometric relation between the buoy and mooring ropes, then suggest the ratchet gear mechanism with the virtual torsion spring element to reduce the dynamic errors during the phase transitions. Time domain simulation is carried out under irregular waves that reflect the actual wave states of the installation area, and we evaluate the theoretical performance using the capture width ratio. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

► Show Figures

Figure 1

5715 KiB

Open AccessArticle

Optimal Control to Increase Energy Production of Wind Farm Considering Wake Effect and Lifetime Estimation

by Jie Tian, Dao Zhou, Chi Su, Frede Blaabjerg and Zhe Chen

Appl. Sci. 2017, 7(1), 65; https://doi.org/10.3390/app7010065 - 11 Jan 2017

Cited by 19 | Viewed by 5514

Abstract

In a wind farm, the upstream wind turbine may cause power loss to the downstream wind turbines due to the wake effect. Meanwhile, the energy production is determined by the power generation and the lifetime of the wind turbine. In this paper, an optimal active power control method is proposed to maximize the energy production of wind farms by considering the wake effect and the lifetime of wind turbine. It starts with the analysis of the pitch angle curve and active power curve seen from the Maximum Power Point Tracking (MPPT) of individual wind turbines. Taking the wake effect into account, the pitch angle curve and active power curve are optimized with the aim of Maximum Power Generation (MPG) of the wind farm. Afterwards, considering the lifetime of wind turbines, a comparison is offered between the MPPT method and the MPG method for energy production using a simplified two-turbine wind farm as an example. Due to the small range of the effective wake area, it is found that the energy production is almost the same. Finally, the pitch angle curve and active power curve are optimized according to the Maximum Energy Production (MEP) of a wind farm. Upon considering and contrasting the MPPT method and the MEP method, it can be seen that the energy production of wind farms can be increased even in the case of there not being an effective wake area. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

► Show Figures

Figure 1

4441 KiB

Open AccessArticle

Optimized Planning of Power Source Capacity in Microgrid, Considering Combinations of Energy Storage Devices

by Zifa Liu, Yixiao Chen, Ya Luo, Guankun Zhao and Xianlin Jin

Appl. Sci. 2016, 6(12), 416; https://doi.org/10.3390/app6120416 - 09 Dec 2016

Cited by 24 | Viewed by 5261

Abstract

Since renewable energy resource is universally accepted as a promising method to solve the global energy problem, optimal planning and utilization of various distributed generators (DG) and energy storage (ES) devices deserve special concern. ES devices possess various characteristics in power density, energy density, response speed (switching speed) and lifetime. Besides, as different load types have various requirements on power supply reliability according to their importance, coordinated planning with consideration of reasonable matching between power source and load can efficiently improve power supply reliability and economic efficiency via a customized power supply and compensation strategy. This paper focuses on optimization of power source capacity in microgrid and a coordinated planning strategy is proposed with integrated consideration of characteristics of DG, ES and load. An index named additional compensation ratio (ACR) for balancing economic efficiency and reliability is proposed and considered in the strategy. The objective function which aims to minimize life cycle cost (LCC) is established considering economic efficiency, reliability and environmental conservation. The proposed planning strategy and optimizing model is calculated and verified through case study of an autonomy microgrid. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

► Show Figures

Graphical abstract

4441 KiB

Open AccessArticle

Three-Phase PV CHB Inverter for a Distributed Power Generation System

by Pierluigi Guerriero, Marino Coppola, Fabio Di Napoli, Gianluca Brando, Adolfo Dannier, Diego Iannuzzi and Santolo Daliento

Appl. Sci. 2016, 6(10), 287; https://doi.org/10.3390/app6100287 - 11 Oct 2016

Cited by 19 | Viewed by 6506

Abstract

This work deals with the design of a three-phase grid-tied photovoltaic (PV) cascade H-bridge inverter for distributed power conversion. The power balancing among the phases must be properly addressed. In fact, an intra-phase power imbalance—arising from uneven irradiance and temperature conditions—generates a per-phase power imbalance. This latter can be compensated by the injection of a proper zero-sequence voltage, while the intra-phase balance is ensured by means of a hybrid modulation method which is able to guarantee the handling of unequal DC (Direct Current) sources, stable circuit operation, and maximization of PV power production. The digital controller is developed and tested in Matlab/Simulink environment integrated with XSG (Xilinx System Generator), thus allowing an easy transfer on a field-programmable gate array (FPGA) platform and accurately describing the behavior of a real hardware implementation. Thus, numerical results have been considered to prove the effectiveness of the proposed approach. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

► Show Figures

Graphical abstract

1139 KiB

Open AccessArticle

Control Strategy of an Impulse Turbine for an Oscillating Water Column-Wave Energy Converter in Time-Domain Using Lyapunov Stability Method

by Seung Kwan Song and Jin Bae Park

Appl. Sci. 2016, 6(10), 281; https://doi.org/10.3390/app6100281 - 02 Oct 2016

Cited by 14 | Viewed by 5846

Abstract

We present two control strategies for an oscillating water column-wave energy converter (OWC-WEC) in the time domain. We consider a fixed OWC-WEC on the open sea with an impulse turbine module. This system mainly consists of a chamber, turbine and electric generator. For the time domain analysis, all of the conversion stages considering mutualities among them should be analyzed based on the Newtonian mechanics. According to the analysis of Newtonian mechanics, the hydrodynamics of wave energy absorption in the chamber and the turbine aerodynamic performance are directly coupled and share the internal air pressure term via the incompressible air assumption. The turbine aerodynamics and the dynamics of the electric generator are connected by torque load through the rotor shaft, which depends on an electric terminal load that acts as a control input. The proposed control strategies are an instant maximum turbine efficiency tracking control and a constant angular velocity of the turbine rotor control methods. Both are derived by Lyapunov stability analysis. Numerical simulations are carried out under irregular waves with various heights and periods in the time domain, and the results with the controllers are analyzed. We then compare these results with simulations carried out in the absence of the control strategy in order to prove the performance of the controllers. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

► Show Figures

Graphical abstract

668 KiB

Open AccessArticle

Variability of the Wind Turbine Power Curve

by Mahesh M. Bandi and Jay Apt

Appl. Sci. 2016, 6(9), 262; https://doi.org/10.3390/app6090262 - 14 Sep 2016

Cited by 25 | Viewed by 10639

Abstract

Wind turbine power curves are calibrated by turbine manufacturers under requirements stipulated by the International Electrotechnical Commission to provide a functional mapping between the mean wind speed

\bar{v}

and the mean turbine power output

\bar{P}

. Wind plant operators employ these [...] Read more.

\bar{v}

and the mean turbine power output

\bar{P}

. Wind plant operators employ these power curves to estimate or forecast wind power generation under given wind conditions. However, it is general knowledge that wide variability exists in these mean calibration values. We first analyse how the standard deviation in wind speed

σ_{v}

affects the mean

\bar{P}

and the standard deviation

σ_{P}

of wind power. We find that the magnitude of wind power fluctuations scales as the square of the mean wind speed. Using data from three planetary locations, we find that the wind speed standard deviation

σ_{v}

systematically varies with mean wind speed

\bar{v}

, and in some instances, follows a scaling of the form

σ_{v} = C \times {\bar{v}}^{α}

; C being a constant and

α

a fractional power. We show that, when applicable, this scaling form provides a minimal parameter description of the power curve in terms of

\bar{v}

alone. Wind data from different locations establishes that (in instances when this scaling exists) the exponent

α

varies with location, owing to the influence of local environmental conditions on wind speed variability. Since manufacturer-calibrated power curves cannot account for variability influenced by local conditions, this variability translates to forecast uncertainty in power generation. We close with a proposal for operators to perform post-installation recalibration of their turbine power curves to account for the influence of local environmental factors on wind speed variability in order to reduce the uncertainty of wind power forecasts. Understanding the relationship between wind’s speed and its variability is likely to lead to lower costs for the integration of wind power into the electric grid. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

► Show Figures

Figure 1

2875 KiB

Open AccessArticle

Control and Modulation Techniques for a Centralized PV Generation System Grid Connected via an Interleaved Inverter

by Gianluca Brando, Adolfo Dannier, Andrea Del Pizzo and Ivan Spina

Appl. Sci. 2016, 6(9), 261; https://doi.org/10.3390/app6090261 - 13 Sep 2016

Cited by 5 | Viewed by 6403

Abstract

In the context of grid connected photovoitaic (PV) generation systems, there are two paramount aspects regarding the Maximum Power Point Tracking (MPPT) of the photovoltaic units and the continuity of the service. The most diffused MPPT algorithms are based on either perturb and observe, or on an incremental conductance approach and need both PV current and voltage measurements. Several topology reconfigurable converters are also associated with the PV plants, guaranteeing fault-tolerant features. The generation continuity can also be assured by interleaved inverters, which keep the system operating at reduced maximum power in case of failure. In this paper, an evolution of a hysteresis based MPPT algorithm is presented, based on the measurement of only one voltage, together with a novel space vector modulation suitable for a two-channel three-phase grid connected interleaved inverter. The proposed MMPT algorithm and modulation technique are tested by means of several numerical analyses on a PV generation system of about 200 kW maximum power. The results testify the validity of the proposed strategies, showing good performance, even during a fault occurrence and in the presence of deep shading conditions. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

► Show Figures

Graphical abstract

6656 KiB

Open AccessArticle

A Novel Concentrator Photovoltaic (CPV) System with the Improvement of Irradiance Uniformity and the Capturing of Diffuse Solar Radiation

by Nguyen Xuan Tien and Seoyong Shin

Appl. Sci. 2016, 6(9), 251; https://doi.org/10.3390/app6090251 - 08 Sep 2016

Cited by 30 | Viewed by 9486

Abstract

This paper proposes a novel concentrator photovoltaic (CPV) system with improved irradiation uniformity and system efficiency. CPV technology is very promising its for highly efficient solar energy conversion. A conventional CPV system usually uses only one optical component, such as a refractive Fresnel lens or a reflective parabolic dish, to collect and concentrate solar radiation on the solar cell surface. Such a system creates strongly non-uniform irradiation distribution on the solar cell, which tends to cause hot spots, current mismatch, and degrades the overall efficiency of the system. Additionally, a high-concentration CPV system is unable to collect diffuse solar radiation. In this paper, we propose a novel CPV system with improved irradiation uniformity and collection of diffuse solar radiation. The proposed system uses a Fresnel lens as a primary optical element (POE) to concentrate and focus the sunlight and a plano-concave lens as a secondary optical element (SOE) to uniformly distribute the sunlight over the surface of multi-junction (MJ) solar cells. By using the SOE, the irradiance uniformity is significantly improved in the system. Additionally, the proposed system also captures diffuse solar radiation by using an additional low-cost solar cell surrounding MJ cells. In our system, incident direct solar radiation is captured by MJ solar cells, whereas incident diffuse solar radiation is captured by the low-cost solar cell. Simulation models were developed using a commercial optical simulation tool (LightTools™). The irradiance uniformity and efficiency of the proposed CPV system were analyzed, evaluated, and compared with those of conventional CPV systems. The analyzed and simulated results show that the CPV system significantly improves the irradiance uniformity as well as the system efficiency compared to the conventional CPV systems. Numerically, for our simulation models, the designed CPV with the SOE and low-cost cell provided an optical power ratio increase of about 17.12% compared to the conventional CPV without the low-cost cell, and about 10.26% compared to the conventional CPV without using both the SOE and additional low-cost cell. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

► Show Figures

Figure 1

Review

Jump to: Editorial, Research

1005 KiB

Open AccessReview

A Review of Flywheel Energy Storage System Technologies and Their Applications

by Mustafa E. Amiryar and Keith R. Pullen

Appl. Sci. 2017, 7(3), 286; https://doi.org/10.3390/app7030286 - 16 Mar 2017

Cited by 332 | Viewed by 42981

Abstract

Energy storage systems (ESS) provide a means for improving the efficiency of electrical systems when there are imbalances between supply and demand. Additionally, they are a key element for improving the stability and quality of electrical networks. They add flexibility into the electrical system by mitigating the supply intermittency, recently made worse by an increased penetration of renewable generation. One energy storage technology now arousing great interest is the flywheel energy storage systems (FESS), since this technology can offer many advantages as an energy storage solution over the alternatives. Flywheels have attributes of a high cycle life, long operational life, high round-trip efficiency, high power density, low environmental impact, and can store megajoule (MJ) levels of energy with no upper limit when configured in banks. This paper presents a critical review of FESS in regards to its main components and applications, an approach not captured in earlier reviews. Additionally, earlier reviews do not include the most recent literature in this fast-moving field. A description of the flywheel structure and its main components is provided, and different types of electric machines, power electronics converter topologies, and bearing systems for use in flywheel storage systems are discussed. The main applications of FESS are explained and commercially available flywheel prototypes for each application are described. The paper concludes with recommendations for future research. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

► Show Figures

Figure 1

465 KiB

Open AccessReview

Review of the Remaining Useful Life Prognostics of Vehicle Lithium-Ion Batteries Using Data-Driven Methodologies

by Lifeng Wu, Xiaohui Fu and Yong Guan

Appl. Sci. 2016, 6(6), 166; https://doi.org/10.3390/app6060166 - 27 May 2016

Cited by 146 | Viewed by 10212

Abstract

Lithium-ion batteries are the primary power source in electric vehicles, and the prognosis of their remaining useful life is vital for ensuring the safety, stability, and long lifetime of electric vehicles. Accurately establishing a mechanism model of a vehicle lithium-ion battery involves a complex electrochemical process. Remaining useful life (RUL) prognostics based on data-driven methods has become a focus of research. Current research on data-driven methodologies is summarized in this paper. By analyzing the problems of vehicle lithium-ion batteries in practical applications, the problems that need to be solved in the future are identified. Full article

(This article belongs to the Special Issue Advancing Grid-Connected Renewable Generation Systems)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Advancing Grid-Connected Renewable Generation Systems

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (14 papers)

Editorial

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI