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12 pages, 2263 KiB

Open AccessArticle

Examination of Multi-Pulse Rectifiers of PES Systems Used on Airplanes Compliant with the Concept of Electrified Aircraft

by Lucjan Setlak and Rafał Kowalik

Appl. Sci. 2019, 9(8), 1520; https://0-doi-org.brum.beds.ac.uk/10.3390/app9081520 - 12 Apr 2019

Cited by 16 | Viewed by 3961

Abstract

This article focuses on power electronic multi-pulse 12-, 24- and 36-impulse rectifiers based on multi-winding rectifier transformers. The effectiveness of voltage processing with different variants of supply voltage sources is discussed and arguments are formulated for limiting oneself to 24-pulse processing, which is [...] Read more.

This article focuses on power electronic multi-pulse 12-, 24- and 36-impulse rectifiers based on multi-winding rectifier transformers. The effectiveness of voltage processing with different variants of supply voltage sources is discussed and arguments are formulated for limiting oneself to 24-pulse processing, which is used in the latest technological solutions of modern aviation technology. The main purpose of this article is to conduct a study (analysis, mathematical models, simulations) of selected multi-pulse rectifiers in the context of testing their properties in relation to the impact on the electrified power supply network. The secondary objective of the article is to assess the possibility of using Matlab/Simulink to analyze the work of rectifier circuits implemented in aircraft networks compliant with the more/all electric aircraft (MEA/AEA) concept. The simulation tests included designing a typical auto-transformer rectifier unit (ATRU) system in the Simulink program and generating output voltage waveforms in this program in the absence of damage to the rectifier elements. In the final part of this work, based on a critical analysis of the literature on the subject of the study, simulations were made of exemplary rectifiers in the Matlab/Simulink programming environment along with their brief analysis. Practical conclusions resulting from the implementation of the MEA/AEA concept in modern aviation were formulated. Full article

(This article belongs to the Special Issue Emerging Power Electronics Technologies)

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24 pages, 6498 KiB

Open AccessArticle

Circulating Current Reduction in MMC-HVDC System Using Average Model

by Kamran Hafeez, Shahid A. Khan, Alex Van den Bossche and Qadeer Ul Hasan

Appl. Sci. 2019, 9(7), 1383; https://0-doi-org.brum.beds.ac.uk/10.3390/app9071383 - 01 Apr 2019

Cited by 9 | Viewed by 5656

Abstract

Modular multilevel converters (MMCs) are quickly emerging as a suitable technology for a voltage-source converter-based high-voltage direct-current (VSC-HVDC) transmission systems due to its numerous advantages as reported in literature. However, for a large DC-network, MMCs require large numbers of sub-modules (SMs) and switches, [...] Read more.

Modular multilevel converters (MMCs) are quickly emerging as a suitable technology for a voltage-source converter-based high-voltage direct-current (VSC-HVDC) transmission systems due to its numerous advantages as reported in literature. However, for a large DC-network, MMCs require large numbers of sub-modules (SMs) and switches, which makes its modeling very challenging and computationally complex using electromagnetic transient (EMT) programs. Average Value Model (AVM) provides a relatively better solution to model MMCs by combining cells as an arm equivalent circuit. Circulating current is an important issue related to the performance and stability of MMCs. Due to circulating currents, power loss in a converter increases as root mean square (RMS) values of the arm current increases. The traditional method for inserting SMs in each arm is based on direct modulation, which does not compensate for the arm voltage oscillations, and generates circulating current in each leg of a three-phase MMC. This paper presents a new method for reducing the circulating current by adding 2nd and 4th harmonics in the upper and lower arm currents of an MMC. Less capacitor energy variations are obtained by the proposed method compared to traditional direct modulation methods. The proposed method is tested on a common symmetrical monopole (point-to-point) MMC-HVDC system using vector current control strategy in PSCAD/EMTDC software. Analytical and simulation results show the effectiveness of the new method in minimizing the circulating current and arm voltage oscillation reductions as compared to the direct modulation approach. Full article

(This article belongs to the Special Issue Emerging Power Electronics Technologies)

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16 pages, 8997 KiB

Open AccessArticle

SVPWM Method for Multilevel Indirect Matrix Converter with Eliminate Common Mode Voltage

by Nguyen Dinh Tuyen and Le Minh Phuong

Appl. Sci. 2019, 9(7), 1342; https://0-doi-org.brum.beds.ac.uk/10.3390/app9071342 - 30 Mar 2019

Viewed by 3800

Abstract

The multilevel indirect matrix converter (IMC) is a merit of power converter for feeding a three-phase load from three-phase power supply because it has several attractive features such as: Sinusoidal input/output currents, bidirectional power flow, long lifetime due to the absence of bulky [...] Read more.

The multilevel indirect matrix converter (IMC) is a merit of power converter for feeding a three-phase load from three-phase power supply because it has several attractive features such as: Sinusoidal input/output currents, bidirectional power flow, long lifetime due to the absence of bulky electrolytic capacitors. As compared to the conventional IMC, the multilevel IMC provides high output performance by increasing the level of output voltage. In this paper, the novel approach topology of multilevel IMC by using the combination of the cascaded rectifier and the three-level T-Type inverter is introduced. Furthermore, the new space vector pulse width modulation (SVPWM) method for the presented multilevel IMC that eliminate the common-mode voltage is proposed in this paper. The simulation study is carried out in PSIM software to verify the proposed modulation method. Then, an experimental system is built using a three-phase RL load, a multilevel IMC, a DSP controller board and other elements to verify the effectiveness of the proposed modulation method. Some simulation and experimental results are illustrated to confirm the theory analysis. Full article

(This article belongs to the Special Issue Emerging Power Electronics Technologies)

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20 pages, 6326 KiB

Open AccessArticle

Research on the Structure and Control Strategy of a Novel Power Electronic Transformer for AC/DC Hybrid Distribution Network

by Jingguo Rong, Xin Ai, Yunning Li and Dapeng Ren

Appl. Sci. 2019, 9(4), 727; https://0-doi-org.brum.beds.ac.uk/10.3390/app9040727 - 19 Feb 2019

Cited by 4 | Viewed by 2733

Abstract

Power electronic transformers (PETs), as the core devices of the energy internet, are the key to achieve both effective consumption for renewable energy and the safe and coordinated operation for AC/DC hybrid system. In order to overcome the shortcomings of the existing PETs, [...] Read more.

Power electronic transformers (PETs), as the core devices of the energy internet, are the key to achieve both effective consumption for renewable energy and the safe and coordinated operation for AC/DC hybrid system. In order to overcome the shortcomings of the existing PETs, a novel PET with an improved structure that applicable for multi-voltage level AC/DC hybrid distribution network is proposed. The topology of the proposed PET is analyzed, and the corresponding control methods are suggested for different parts. The input stage utilizes the modular multilevel converter structure and applies the virtual synchronous machine control strategy to enhance the inertia and damping of the system. The power of the output stage is adjusted flexibly and that enables the PET to provide certain power support to the upper grid and participate in its primary frequency regulation. A combined connection of input-series output-series and input-series output-parallel is applied for the dual-active-bridge modules of the isolation stage to enable network interconnection and electrical isolation of AC/DC grids with significantly different voltage levels. A power coordinated control method is then proposed to meet the power demand of the distribution networks connected to the output stage and ensure stable operations of PET simultaneously. The reliability and efficiency of the proposed PET topology and control strategy for AC/DC hybrid distribution network are finally verified via PSCAD/EMTDC simulation. Full article

(This article belongs to the Special Issue Emerging Power Electronics Technologies)

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13 pages, 1540 KiB

Open AccessFeature PaperArticle

Low-Voltage Solid-State DC Breaker for Fault Protection Applications in Isolated DC Microgrid Cluster

by Mohammad Aman Yaqobi, Hidehito Matayoshi, Mir Sayed Shah Danish, Mohammed Elsayed Lotfy, Abdul Motin Howlader and Senjyu Tomonobu

Appl. Sci. 2019, 9(4), 723; https://0-doi-org.brum.beds.ac.uk/10.3390/app9040723 - 19 Feb 2019

Cited by 24 | Viewed by 4218

Abstract

Due to the interconnected scheme of multiple components, such as distributed generators, storage systems, and loads through converters to a common bus in DC microgrids, the possibility of fault occurrence is increasing significantly. Meanwhile, due to the huge and rapid increase of short-circuit [...] Read more.

Due to the interconnected scheme of multiple components, such as distributed generators, storage systems, and loads through converters to a common bus in DC microgrids, the possibility of fault occurrence is increasing significantly. Meanwhile, due to the huge and rapid increase of short-circuit currents, the development of a small- and large-scale DC system requires a reliable and fast protection system to ensure fault clearance and maintain safety for the rest of the system. Thus, fault protection has been focused on as one of the most critical issues in a direct current network. The application of traditional circuit-breakers for DC fault protection has the drawback of slow operation, which requires a high rating power equipment. Recently, the high speed and excellent performance capabilities of semiconductor breakers have attracted a lot of attention and been considered as an optimal solution for fast DC fault interruption. In this study, a bidirectional Insulated-Gate Bipolar Transistor (IGBT) semiconductor breaker, suitable for the fault protection of low-voltage DC networks, is proposed. The operating characteristics of this breaker are based on changes in the circuit current and terminal voltage of IGBTs. It detects the abrupt change of the terminal voltage as an abnormal condition and isolates the faulted branch in a short time to prevent the operation disturbance in the healthy part of the network. Therefore, for the entire protection of a typical 400V DC-microgrid cluster, breakers need to be integrated and examined in each branch and the interconnected lines. The proposed protection method in this study is examined in a Simulink^®/MATLAB environment to analyze and assess its operation. Full article

(This article belongs to the Special Issue Emerging Power Electronics Technologies)

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12 pages, 5078 KiB

Open AccessArticle

Voltage Ride through Control Strategy of Modular Multilevel Converter under Unbalanced Voltage Sag

by Seyed Mehdi Hakimi and Amin Hajizadeh

Appl. Sci. 2019, 9(3), 551; https://0-doi-org.brum.beds.ac.uk/10.3390/app9030551 - 07 Feb 2019

Cited by 1 | Viewed by 2470

Abstract

This paper develops modeling and describes a control strategy for a modular multilevel converter (MMC) for grid-connected renewable energy systems. The proposed model can be used to simulate MMC activity during normal and faulty situations. Firstly, a dynamic model of a grid-connected MMC [...] Read more.

This paper develops modeling and describes a control strategy for a modular multilevel converter (MMC) for grid-connected renewable energy systems. The proposed model can be used to simulate MMC activity during normal and faulty situations. Firstly, a dynamic model of a grid-connected MMC (GC-MMC), based upon the symmetrical component of voltages and currents, was designed. Then an adaptive robust control approach was established in order to follow the reference currents of the converter and stabilize the submodule (SM) capacitor voltage. The positive and negative sequences of reference currents that were given from the demanded active and reactive power during grid voltage disturbance and a normal situation were then utilized in control loops. Finally, the numerical results for the performance of the MMC throughout voltage sag conditions and the effect of uncertainties on the filter parameters during changing power demands were evaluated. The results specified that the current control strategy is more potent under voltage sag situations and able to fulfill the stability requirements of the MMC. Full article

(This article belongs to the Special Issue Emerging Power Electronics Technologies)

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12 pages, 4471 KiB

Open AccessArticle

On the Innovation Design for Two-Motor Transmissions with Eight-Link Mechanisms in the Electric Vehicles

by Ngoc-Tan Hoang and Hong-Sen Yan

Appl. Sci. 2019, 9(1), 140; https://0-doi-org.brum.beds.ac.uk/10.3390/app9010140 - 03 Jan 2019

Cited by 5 | Viewed by 3965

Abstract

A decade ago, electric vehicles (EV) made a boom in the automobile market, as they started to become a growing market section in the transportation space. The reasons behind the boom were to decrease environmental pollution by reducing the use of fossil fuels, [...] Read more.

A decade ago, electric vehicles (EV) made a boom in the automobile market, as they started to become a growing market section in the transportation space. The reasons behind the boom were to decrease environmental pollution by reducing the use of fossil fuels, lowering transportation operating costs, and increased general consumer interest in the new technology. This work generates a streamlined process for the design and simulation of motor transmissions with eight-link mechanisms. This procedure presents a wide range of motor transmissions such as 34 new clutchless systems and 34 new clutched systems. Two novel feasible motor transmissions of the design process are taken as a sample to dissect the working principle conjoined both power flow paths and operation modes. In addition, these designs are conducted for modeling and computer simulation procedures that obtain the results of the energy management strategy and operation mode variation. Full article

(This article belongs to the Special Issue Emerging Power Electronics Technologies)

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Review

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19 pages, 4367 KiB

Open AccessReview

Review of VSG Control-Enabled Universal Compatibility Architecture for Future Power Systems with High-Penetration Renewable Generation

by Xiangwu Yan and Weichao Zhang

Appl. Sci. 2019, 9(7), 1484; https://0-doi-org.brum.beds.ac.uk/10.3390/app9071484 - 09 Apr 2019

Cited by 20 | Viewed by 3852

Abstract

Due to the irreversible energy substitution from fossil fuels to clean energy, the development trend of future power systems is based on renewable energy generation. However, due to the incompatibility of converter-based non-dispatchable renewable energy generation, the stability and reliability of traditional power [...] Read more.

Due to the irreversible energy substitution from fossil fuels to clean energy, the development trend of future power systems is based on renewable energy generation. However, due to the incompatibility of converter-based non-dispatchable renewable energy generation, the stability and reliability of traditional power systems deteriorate as more renewables are introduced. Since conventional power systems are dominated by synchronous machines (SM), it is natural to utilize a virtual synchronous generator (VSG) control strategy that intimates SM characteristics on integrated converters. The VSG algorithm developed in this paper originates from mimicking mathematic models of synchronous machines. Among the different models of implementation, the second-order model is simple, stable, and compatible with the control schemes of current converters in traditional power systems. The VSG control strategy is thoroughly researched and case studied for various converter-interfaced systems that include renewable generation, energy storage, electric vehicles (EV), and other energy demands. VSG-based integration converters can provide grid services such as spinning reserves and inertia emulation to the upper grids of centralized plants, distributed generation networks, and microgrids. Thus, the VSG control strategy has paved a feasible way for an evolutionary transition to a power electronics-based future power grid. By referring to the knowledge of traditional grids, a hierarchical system of operations can be established. Finally, generation and loads can be united in universal compatibility architecture under consolidated synchronous mechanisms. Full article

(This article belongs to the Special Issue Emerging Power Electronics Technologies)

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