Special Issue "Power Electronics in DC-Microgrid Systems"

A special issue of Energies (ISSN 1996-1073).

Deadline for manuscript submissions: closed (31 July 2018).

Special Issue Editors

Prof. Jih-Sheng (Jason) Lai
E-Mail Website
Guest Editor
Director, Future Energy Electronics Center, James S. Tucker Professor, Virginia Polytechnic Institute and State University, International Chair Professor, Department of Vehicle Engineering, National Taipei University of Technology, Taiwan
Interests: high-power electronics converter topologies; motor drives; utility power electronics interfaces and application issues
Special Issues and Collections in MDPI journals
PhD. Ching-Ming Lai
E-Mail Website
Guest Editor
Prof. Liang-Rui Chen
E-Mail
Guest Editor
Department of Electrical Engineering, National Changhua University of Education, Taiwan
Interests: power electronics; battery-powered circuit design; renewable energy

Special Issue Information

Dear Colleagues,

We are inviting submissions to a Special Issue of Energies on the subject of “Power Electronics in DC-Microgrid Systems”.

With the rapid growth of direct-current (DC) coupled sources and loads, including photovoltaic (PV) generators, energy storage devices such as batteries and supercapacitors, light-emitting-diodes (LEDs), and electronics equipment, the low-voltage DC distribution networks and structured DC-microgrids are emerging as a natural platform to integrate distributed energy sources. However, there are a number of technical challenges: a lack of standardized interconnect and protection equipment, inadequate stability, and versatile control design. The availability of wide bandgap power semiconductor devices further pushes the power electronics design toward high efficiency and high power density for DC microgrids. In the past, the interest of the power electronics community was moving from a single power electronics converter to multiple distributed systems that encompass a number of converters connected in either series or parallel, forming a number of DC busses with different voltage levels. Recently, with the advance of new DC power conversion technologies, several ongoing standards, alliances, and initiatives are bringing the possibility of developing future homes, offices, buildings, campuses, datacenters, ships, satellites, aircrafts, and other electrical power systems to operate totally or dominantly in DC. Research is being carried out in both the system and component levels of modelling, control, and stability of structured DC-microgrids. Novel high-efficiency topologies and protections are also key nontrivial issues when developing practical DC-microgrids.

Prospective authors are invited to submit original contributions, survey papers, or tutorials for review and publication in this special issue on DC-microgrids.

Papers with applications in nature are particularly welcome.

Topics of interest for publication include, but are not limited to:

  • Power electronic systems—converters and emerging technologies;
  • Reliability and resiliency techniques
  • Performance analysis and optimization
  • Powering residential and commercial buildings
  • DC-powered active and passive smart solar houses
  • DC-powered appliances
  • Advanced power electronics
  • Storage technology
  • DC-powered PHEV/EV charging
  • Real-time monitoring and control
  • Manufacturing and cost reduction approaches
  • Partial fault detection
  • Protection schemes
  • Distributed energy generation and integration
  • Standards and policies
Prof. Jih-Sheng (Jason) Lai
Assoc. Prof. Ching-Ming Lai
Prof. Liang-Rui Chen
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 papers will be 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. Energies 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 1800 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.

Published Papers (11 papers)

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Research

Open AccessArticle
Simulation Study of Power Management for a Highly Reliable Distribution System using a Triple Active Bridge Converter in a DC Microgrid
Energies 2018, 11(11), 3178; https://doi.org/10.3390/en11113178 - 16 Nov 2018
Abstract
Owing to the acute energy shortage issue and the increasing energy demands of information and communication technology systems worldwide, the development of a DC microgrid that can utilize renewable energy sources, such as wind and photovoltaic power, has been accelerated. Therefore, power management [...] Read more.
Owing to the acute energy shortage issue and the increasing energy demands of information and communication technology systems worldwide, the development of a DC microgrid that can utilize renewable energy sources, such as wind and photovoltaic power, has been accelerated. Therefore, power management for DC microgrid distributed systems is promoted to achieve high reliability and efficiency in power distribution systems. For industry and power transmission applications such as data centers, power management with the help of DC converters is highly recommended. In this paper, we propose a prototype of a power distribution system with a triple active bridge (TAB) converter for data centers in the DC microgrid. Moreover, we introduce a power management approach for a distribution system using the TAB converter. Finally, we perform simulations of the proposed configuration to verify the controllability of the circuit performance and the high reliability of the system. Full article
(This article belongs to the Special Issue Power Electronics in DC-Microgrid Systems)
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Open AccessArticle
Study and Application of Intelligent Sliding Mode Control for Voltage Source Inverters
Energies 2018, 11(10), 2544; https://doi.org/10.3390/en11102544 - 24 Sep 2018
Abstract
In this paper, an intelligent sliding mode controlled voltage source inverter (VSI) is developed to achieve not only quick transient behavior, but satisfactory steady-state response. The presented approach combines the respective merits of a nonsingular fast terminal attractor (NFTA) as well as an [...] Read more.
In this paper, an intelligent sliding mode controlled voltage source inverter (VSI) is developed to achieve not only quick transient behavior, but satisfactory steady-state response. The presented approach combines the respective merits of a nonsingular fast terminal attractor (NFTA) as well as an adaptive neuro-fuzzy inference system (ANFIS). The NFTA allows no singularity and error states to be converged to the equilibrium within a finite time, while conventional sliding mode control (SMC) leads to long-term (infinite) convergent behavior. However, there is the likelihood of chattering or steady-state error occurring in NFTA due to the overestimation or underestimation of system uncertainty bound. The ANFIS with accurate estimation and the ease of implementation is employed in NFTA for suppressing the chatter or steady-state error so as to improve the system’s robustness against uncertain disturbances. Simulation results display that this described approach yields low distorted output wave shapes and quick transience in the presence of capacitor input rectifier loading as well as abrupt connection of linear loads. Experimental results conducted on a 1 kW VSI prototype with control algorithm implementation in Texas Instruments DSP (digital signal processor) support the theoretic analysis and reaffirm the robust performance of the developed VSI. Because the proposed VSI yields remarkable benefits over conventional terminal attractor VSIs on the basis of computational quickness and unsophisticated realization, the presented approach is a noteworthy referral to the designers of correlated VSI applications in future, such as DC (direct current) microgrids and AC (alternating current) microgrids, or even hybrid AC/DC microgrids. Full article
(This article belongs to the Special Issue Power Electronics in DC-Microgrid Systems)
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Open AccessArticle
A Fast DC Fault Detection Method for Multi-Terminal AC/DC Hybrid Distribution Network Based on Voltage Change Rate of DC Current-Limiting Inductor
Energies 2018, 11(7), 1828; https://doi.org/10.3390/en11071828 - 12 Jul 2018
Cited by 2
Abstract
The rapid detection of direct current (DC) faults is one of the key technologies for the development of multi-terminal alternating current (AC)/DC hybrid distribution networks. The DC fault current rises quickly and affects the whole network. Therefore, DC faults must be detected much [...] Read more.
The rapid detection of direct current (DC) faults is one of the key technologies for the development of multi-terminal alternating current (AC)/DC hybrid distribution networks. The DC fault current rises quickly and affects the whole network. Therefore, DC faults must be detected much faster than AC faults. This paper proposes a fast DC fault detection method based on the voltage change rate of the current-limiting inductor (CLI) for the multi-terminal AC/DC hybrid distribution network. Firstly, the characteristics of the fault voltages and currents and of the CLIs are studied in detail, and the feasibility of using the voltage change rate of the CLI to detect DC fault is analyzed. Based on this, a primary fault detection method is proposed to identify the faulty line, determine the fault type and the fault poles using the amplitudes of the single-ended CLI voltage change rates. For high-resistance DC faults, a backup detection method using the directions and amplitudes of the voltage change rates of the double-ended CLIs is proposed. Finally, the proposed method is verified by MATLAB simulations. The simulation results show that the proposed method can detect all DC faults accurately, and the faulty line, fault type and fault poles can be determined quickly. The proposed method is not affected by the fault location, current-limiting inductance, power reversal of the converters, AC fault and communication delay. Full article
(This article belongs to the Special Issue Power Electronics in DC-Microgrid Systems)
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Open AccessArticle
Large-Signal Stabilization of Three-Phase VSR with Constant Power Load
Energies 2018, 11(7), 1706; https://doi.org/10.3390/en11071706 - 01 Jul 2018
Abstract
As an important interface converter, the three-phase voltage-source rectifier (VSR) connects the grid to DC-input converters. The constant power load (CPL) characteristic of the converter-load often causes large-signal stability problems. In order to solve this problem, the stability boundary of the VSR with [...] Read more.
As an important interface converter, the three-phase voltage-source rectifier (VSR) connects the grid to DC-input converters. The constant power load (CPL) characteristic of the converter-load often causes large-signal stability problems. In order to solve this problem, the stability boundary of the VSR with CPL is analyzed based on the mixed potential theory, and the stability condition under large-signal disturbance is obtained; thus, the jump range of the load power can be estimated. To improve the stability of the system, a voltage loop control scheme based on ADRC is proposed. A theoretical analysis based on the mixed potential theory shows the proposed scheme expands the power jump range of the VSR with CPL effectively, and improves its disturbance rejection performance. Finally, experimental results prove the effectiveness of the proposed control scheme. Full article
(This article belongs to the Special Issue Power Electronics in DC-Microgrid Systems)
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Open AccessArticle
LCL Filter Design with EMI Noise Consideration for Grid-Connected Inverter
Energies 2018, 11(7), 1646; https://doi.org/10.3390/en11071646 - 25 Jun 2018
Cited by 7
Abstract
The grid-injected current total harmonics distortion (THD) and electromagnetic interference (EMI) noise must be considered in a transformer-less grid-connected inverter for a more electric aircraft (MEA) system. This paper develops a procedure for the design of the magnetic components of the LCL filter [...] Read more.
The grid-injected current total harmonics distortion (THD) and electromagnetic interference (EMI) noise must be considered in a transformer-less grid-connected inverter for a more electric aircraft (MEA) system. This paper develops a procedure for the design of the magnetic components of the LCL filter used in harmonic control and EMI reduction of the silicon carbide (SiC) grid-connected inverter in the MEA. The LCL filter is designed with effective harmonic attenuation and a compact size. To meet the space constraint requirement, specific design attention is focused on a customized amorphous cored inductor, with a comprehensive study of the relationships of inductor winding with respect to EMI noise. Reduced THD and EMI are verified through experiments performed on a 30 kW, 230 V/400 Hz three-phase grid-connected inverter prototype with the LCL filter. Full article
(This article belongs to the Special Issue Power Electronics in DC-Microgrid Systems)
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Open AccessArticle
Single-Ended Protection Scheme for VSC-Based DC Microgrid Lines
Energies 2018, 11(6), 1440; https://doi.org/10.3390/en11061440 - 04 Jun 2018
Cited by 1
Abstract
With the promotion of distributed energy and direct current (DC) loads, the DC microgrid is able to provide a higher power quality and improve the grid efficiency. Various technical issues in DC microgrids are still to be addressed, particularly a proper protection scheme [...] Read more.
With the promotion of distributed energy and direct current (DC) loads, the DC microgrid is able to provide a higher power quality and improve the grid efficiency. Various technical issues in DC microgrids are still to be addressed, particularly a proper protection scheme for fault detection and isolation in DC microgrids utilizing voltage source converters (VSCs). In this paper, the pole-to-pole DC fault transient behavior of the VSC-based microgrids is firstly analyzed with four successive stages, and then the exact requirements for protections are presented. Furthermore, a novel single-ended protection scheme based on local transient signals is proposed, which needs no data transmission or synchronization between two ends, ensuring the speed. A four-terminal DC microgrid model was built in PSCAD/EMTDC. Numerous simulations have demonstrated the validity of the proposed scheme. Full article
(This article belongs to the Special Issue Power Electronics in DC-Microgrid Systems)
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Open AccessArticle
Photovoltaic Integrated Shunt Active Power Filter with Simpler ADALINE Algorithm for Current Harmonic Extraction
Energies 2018, 11(5), 1152; https://doi.org/10.3390/en11051152 - 04 May 2018
Cited by 2
Abstract
This manuscript presents a significant work in improving the current harmonics extraction algorithm and indirectly improving the injection current produced by a single-phase Photovoltaic Shunt Active Power Filter (PV SAPF). Improvement to the existing adaptive linear neuron (ADALINE) technique has been carried out, [...] Read more.
This manuscript presents a significant work in improving the current harmonics extraction algorithm and indirectly improving the injection current produced by a single-phase Photovoltaic Shunt Active Power Filter (PV SAPF). Improvement to the existing adaptive linear neuron (ADALINE) technique has been carried out, leading to the formation of a simpler ADALINE; it is expected to perform as fast as the current harmonics extraction algorithm. Further analysis on the DC link capacitor control algorithm, called “self-charging with step size error cancellation”, was also done to inspect the performance of the algorithm in a single-phase photovoltaic shunt active power filter system. Both algorithms, configured in single-phase PV SAPF, were simulated in MATLAB/Simulink (R2012b). A laboratory prototype was developed, and the algorithms were computed on a TMS320F28335 Digital Signal Processing (DSP) board for hardware implementation purposes. From the acquired results, the simpler ADALINE algorithm has effectively performed with lower total harmonic Distortion (THD) and outstanding compensation. The established algorithm of self-charging with step size error cancellation works well with single-phase PV SAPF and has shown less overshoot, a fast response time, and minimal energy losses. Full article
(This article belongs to the Special Issue Power Electronics in DC-Microgrid Systems)
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Open AccessArticle
A High-Gain Reflex-Based Bidirectional DC Charger with Efficient Energy Recycling for Low-Voltage Battery Charging-Discharging Power Control
Energies 2018, 11(3), 623; https://doi.org/10.3390/en11030623 - 11 Mar 2018
Cited by 2
Abstract
This study proposes a high-gain reflex-charging-based bidirectional DC charger (RC-BDC) to enhance the battery charging efficiency of light electric vehicles (LEV) in a DC-microgrid. The proposed charger topology consists of an unregulated level converter (ULC) and a two-phase interleaved buck-boost charge-pump converter (IBCPC), [...] Read more.
This study proposes a high-gain reflex-charging-based bidirectional DC charger (RC-BDC) to enhance the battery charging efficiency of light electric vehicles (LEV) in a DC-microgrid. The proposed charger topology consists of an unregulated level converter (ULC) and a two-phase interleaved buck-boost charge-pump converter (IBCPC), which together provide low ripple and high voltage conversion ratio. As the high-gain RC-BDC charges, the LEV’s battery with reflex charging currents, high battery charging efficiency, and prolonged battery life cycles are achieved. This is possible due to the recovering of negative pulse energy of reflex charging currents to reduce charge dissipations within LEV’s batteries. Derivations of the operating principles of the high-gain RC-BDC, analyses of its topology, and the closed-loop control designs were presented. Simulations and experiments were implemented with battery voltage of 48 V and DC-bus voltage of 400 V for a 500 W prototype. The results verify the feasibility of the proposed concept and were compared with the typical constant-current/constant-voltage (CC/CV) charger. The comparison shows that the proposed high gain RC-BDC improves battery charging speed and reduces the battery thermal deterioration effect by about 12.7% and 25%, respectively. Full article
(This article belongs to the Special Issue Power Electronics in DC-Microgrid Systems)
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Open AccessFeature PaperArticle
High-Efficiency Isolated Photovoltaic Microinverter Using Wide-Band Gap Switches for Standalone and Grid-Tied Applications
Energies 2018, 11(3), 569; https://doi.org/10.3390/en11030569 - 06 Mar 2018
Cited by 5
Abstract
An isolated photovoltaic micro-inverter for standalone and grid-tied applications is designed and implemented to achieve high efficiency. System configuration and design considerations, including the proposed active-clamp forward-flyback resonant converter for the DC-DC stage and a dual-frequency full-bridge inverter for the DC-AC stage, are [...] Read more.
An isolated photovoltaic micro-inverter for standalone and grid-tied applications is designed and implemented to achieve high efficiency. System configuration and design considerations, including the proposed active-clamp forward-flyback resonant converter for the DC-DC stage and a dual-frequency full-bridge inverter for the DC-AC stage, are analyzed and discussed. A prototype microinverter system is built and tested. Experimental results verify the feasibility of the proposed system, which achieves 95% power conversion efficiency at full load. Full article
(This article belongs to the Special Issue Power Electronics in DC-Microgrid Systems)
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Open AccessArticle
Dynamic Wireless Power Transfer for Logistic Robots
Energies 2018, 11(3), 527; https://doi.org/10.3390/en11030527 - 28 Feb 2018
Cited by 8
Abstract
The prospect of using robots in warehouses or supply chain processes is increasing due to the growth of the online retail market. This logistic robot is available in the market and uses a battery as energy storage device. However, this battery is large [...] Read more.
The prospect of using robots in warehouses or supply chain processes is increasing due to the growth of the online retail market. This logistic robot is available in the market and uses a battery as energy storage device. However, this battery is large and heavy. Therefore, it needs a long recharging time. Dynamic Wireless Power Transfer (DWPT) can be an alternative to the conventional charging system because of its safety and flexibility that enables in motion charging. DWPT reduces the battery requirement size and capacity. Hence the stored energy can be used effectively for load transportation. A compensation with an inductor and two capacitors in the transmitter side, and a series connected capacitor in the receiver side which is named LCC-S compensation type has the capability to maintain the transmitter current with a fixed frequency operation. It provides less variation of the output voltage in response to the load variation. Moreover, the compensation of the receiver side uses only a single series capacitor which is low-cost. The analysis, modeling, and design procedures are discussed in this paper as well as the hardware implementation and verification of a 1.5 kW maximum power DWPT. The experiment shows the capability of the proposed system and shows maximum efficiency can reach 91.02%. Full article
(This article belongs to the Special Issue Power Electronics in DC-Microgrid Systems)
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Open AccessArticle
Series-Connected High Frequency Converters in a DC Microgrid System for DC Light Rail Transit
Energies 2018, 11(2), 266; https://doi.org/10.3390/en11020266 - 23 Jan 2018
Cited by 1
Abstract
This paper studies and presents a series-connected high frequency DC/DC converter connected to a DC microgrid system to provide auxiliary power for lighting, control and communication in a DC light rail vehicle. Three converters with low voltage and current stresses of power devices [...] Read more.
This paper studies and presents a series-connected high frequency DC/DC converter connected to a DC microgrid system to provide auxiliary power for lighting, control and communication in a DC light rail vehicle. Three converters with low voltage and current stresses of power devices are series-connected with single transformers to convert a high voltage input to a low voltage output for a DC light rail vehicle. Thus, Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) with a low voltage rating and a turn-on resistance are adopted in the proposed circuit topology in order to decrease power losses on power switches and copper losses on transformer windings. A duty cycle control with an asymmetric pulse-width modulation is adopted to control the output voltage at the desired voltage level. It is also adopted to reduce switching losses on MOSFETs due to the resonant behavior from a leakage inductor of an isolated transformer and output capacitor of MOSFETs at the turn-on instant. The feasibility and effectiveness of the proposed circuit have been verified by a laboratory prototype with a 760 V input and a 24 V/60 A output. Full article
(This article belongs to the Special Issue Power Electronics in DC-Microgrid Systems)
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