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Number of results: 18
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Abstract

Slope deformations, i.e., all types of landslides of rock masses (flow, creep, fall down, etc.), caused by gravitational forces, are the most widespread implementation of geological hazards and a negative geomorphological phenomenon that threatens the security of the population, destroy all utility values of the affected regions, negatively affects the environment, and cause considerable economic damage. Nowadays, the Global Navigation Satellite Systems (GNSS) provide accurate data for precise observations around the world due to the growing number of satellites from multiple operators, as well as more powerful and advanced technologies and the implementation of mathematical and physical models more accurately describing systematic errors that degrade GNSS observations such as ionospheric, tropospheric, and relativistic effects or multipath. The correct combination of measurement methods provides even more precise, i.e., better measurement results or estimates of unknown parameters. The combination of measurement procedures and their significant evaluations represent the essential attribute of deformation monitoring of landslides concerning the protection of the environment and the population’s safety in the interest areas for the sustainable development of human society. This article presents the establishment and use of a local geodetic network in particular local space for various needs. Depending upon the specific conditions, it is possible to use GNSS technology to obtain accurate observations and achieve the results applicable to the deformation survey for subsequent processing of the adjustment procedure.
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Authors and Affiliations

Gabriel Weiss
1
ORCID: ORCID
Slavomir Labant
1
ORCID: ORCID
Juraj Gasinec
1
ORCID: ORCID
Hana Stankova
2
ORCID: ORCID
Pavel Cernota
2
ORCID: ORCID
Erik Weiss
3
ORCID: ORCID
Roland Weiss
3
ORCID: ORCID

  1. Technical University of Kosice, Kosice, Slovakia
  2. VSB – Technical University of Ostrava, Ostrava, Czech Republic
  3. University of Economics in Bratislava, Bratislava, Slovakia
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Abstract

Real objects in horizontal projection often have a complex geometry. Their irregular shape causes issues during analyses and calculations that consider their geometry. The paper proposes the replacement of real-world objects with equivalent rectangles (ER). The paper also defines the geometric criteria of ER as well as ER parameters and methods for calculating them. The paper also demonstrates the difference in the duration of calculations for different types of rectangles (equivalent rectangle with the same area, surrounding rectangle with the smallest area, inscribed rectangle with the largest area). The presented approach has been illustrated with three case studies. The first one is the application of ER to underground mining cavities to determine post-mining deformations of the ground surface. In the second study, an ER was applied to analyse the geometry of agricultural parcels in a selected part of a rural settlement. ER can help assess whether the spatial layout is faulty and if a planning intervention is necessary. The third example describes a building’s geometry with an ER. Regarding the simplification of building’s geometry, it is crucial to replace a simplified building with a model that has the same centroid location and the same area. It is the perfect solution for rapid analyses of displaying objects on maps in various scales.
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Authors and Affiliations

Andrzej Kwinta
1
ORCID: ORCID
Joanna Bac-Bronowicz
2
ORCID: ORCID

  1. University of Agriculture in Krakow, Krakow, Poland
  2. Wroclaw University of Science and Technology, Wroclaw, Poland
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Abstract

The problem of outlying observations is very well-known in the surveying data processing. Outliers might have several sources, different magnitudes, and shares within the whole observation set. It means that it is not possible to propose one universal method to deal with such observations. There are two general approaches in such a context: data cleaning or robust estimation. For example, the robust M-estimation has found many practical applications. However, there are other options, such as R-estimation or the absolute M split estimation. The latter method was created to be less sensitive to outliers than the squared M split estimation (the basic variant of Msplit estimation). From the theoretical point of view, the absolute M split estimation cannot be classified as a robust method; however, it was proved that it could be used in such a context under certain conditions. The paper presents the primary comparison between that method and a conventional robust M-estimation. The results show that the absolute M split estimation predominates over the classical methods, especially when the percentage of outliers is high. Thus, that method might be used to process LiDAR data, including mismeasured points. Processing synthetic data from terrestrial laser scanning or airborne laser scanning confirms that the absolute M split / estimation can deal with outliers sufficiently.
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Authors and Affiliations

Robert Duchnowski
1
ORCID: ORCID
Patrycja Wyszkowska
1
ORCID: ORCID

  1. University of Warmia and Mazury, Olsztyn, Poland
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Abstract

The applications of the machine learning and programming approaches in cartography has been increasing in recent years. This paper presents a case study of the scripting techniques used for cartographic mapping using Generic Mapping Tools (GMT) and R language (raster and tmaps packages). The aim of the study is environmental mapping of Ghana. The materials include high-resolution raster grids: topography by the General Bathymetric Chart of the Oceans (GEBCO), climate and environmental datasets (TerraClimate) and Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) for geomorphometric analysis (slope, aspect, hillshade and elevations). The methodology includes code snippets commented and explained with details of scripts. It is argued that using consolebased scripting tools for mapping is effective for cartographic workflow due to the logical structure and repeatability of scripts. The results include eight new thematic maps of Ghana performed using scripting approach inGMTscripting toolset and R language for quantitative and qualitative environmental assessment. Maps show correlations between the landforms of Ghana and certain environmental variables (drought index and soil moisture) showing the effects of the topographic relief on the distribution of the continuous geographic fields. These varied in several geographically distinct regions of Ghana: Ashanti (Kumasi), Volta, Savannah, coastal and northern regions. Demonstrated maps show that scripting method works effectively on a wide range of geosciences including environmental, topographic and climate studies. In such a way, this paper contributes both to the regional studies of Ghana and development of cartographic techniques.
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Authors and Affiliations

Polina Lemenkova
1
ORCID: ORCID

  1. Université Libre de Bruxelles, Brussels, Belgium
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Abstract

M split estimation is a novel method developed to process observation sets that include two (or more) observation aggregations. The main objective of the method is to estimate the location parameters of each aggregation without any preliminary assumption concerning the division of the observation set into respective subsets. Up to now, two different variants of M split estimation have been derived. The first and basic variant is the squared M split estimation, which can be derived from the assumption about the normal distribution of observations. The second variant is the absolute M split estimation, which generally refers to the least absolute deviation method. The main objective of the paper is to compare both variants of M split estimation by showing similarities and differences between the methods. The main dissimilarity stems from the different influence functions, making the absolute M split estimation less sensitive to gross errors of moderate magnitude. The empirical analyses presented confirm that conclusion and show that the accuracy of the methods is similar, in general. The absolute M split estimation is more accurate than the squared M split estimation for less accurate observations. In contrast, the squared M split estimation is more accurate when the number of observations in aggregations differs much. Concerning all advantages and disadvantages of M split estimation variants, we recommend using the absolute M split estimation in most geodetic applications.
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Authors and Affiliations

Patrycja Wyszkowska
1
ORCID: ORCID
Robert Duchnowski
1
ORCID: ORCID

  1. University of Warmia and Mazury, Olsztyn, Poland
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Abstract

The applicability of integratedUnmannedAerialVehicle (UAV)-photogrammetry and automatic feature extraction for cadastral or property mapping was investigated in this research paper. Multi-resolution segmentation (MRS) algorithm was implemented on UAVgenerated orthomosaic for mapping and the findings were compared with the result obtained from conventional ground survey technique using Hi-Target Differential Global Positioning System (DGPS) receivers. The overlapping image pairs acquired with the aid of a DJI Mavic air quadcopter were processed into an orthomosaic using Agisoft metashape software while MRS algorithm was implemented for the automatic extraction of visible land boundaries and building footprints at different Scale Parameter (SPs) in eCognition developer software. The obtained result shows that the performance of MRS improves with an increase in SP, with optimal results obtained when the SP was set at 1000 (with completeness, correctness, and overall accuracy of 92%, 95%, and 88%, respectively) for the extraction of the building footprints. Apart from the conducted cost and time analysis which shows that the integrated approach is 2.5 times faster and 9 times cheaper than the conventional DGPS approach, the automatically extracted boundaries and area of land parcels were also compared with the survey plans produced using the ground survey approach (DGPS) and the result shows that about 99% of the automatically extracted spatial information of the properties fall within the range of acceptable accuracy. The obtained results proved that the integration of UAVphotogrammetry and automatic feature extraction is applicable in cadastral mapping and that it offers significant advantages in terms of project time and cost.
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Authors and Affiliations

Oluibukun Gbenga Ajayi
1
ORCID: ORCID
Emmanuel Oruma
1
ORCID: ORCID

  1. Federal University of Technology, Minna, Nigeria
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Abstract

The operating temperature of the transmission line in the traction network is affected by geographical and climatic factors, especially the wind speed. To make better use of the thermal stability transmission capacity of the traction power supply system in improving the short-term emergency transmission capacity, the dynamic rating technology is introduced into the traction power supply system. According to the time-varying characteristics of the actual wind speed, a dynamic rating method of the traction network based on wind speed prediction is proposed and constructed. Based on the time series model in predicting the wind speed series along the corridor of the traction network, the temperature curve of each transmission line under different currents is calculated by combining it with the heat balance equation of an IEEE-738 capacity expansion model, thus the relationship between the peak operating temperature and current of each transmission line in the prediction period is obtained. According to the current distribution coefficient, the capacity increase limit of the traction network is determined. The example shows that the proposed dynamic rating method based on wind speed prediction is an effective method to predict the short-term safe capacity increase limit of the traction network, which can increase the comprehensive capacity of the traction network by about 45% in the next six hours, and the capacity increase effect is obvious, which can provide reference and technical support for short-term emergency dispatching of traction power supply dispatching centres.
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Authors and Affiliations

Zhaoxu Su
1
ORCID: ORCID
Mingxing Tian
1
Lijun Sun
1
Ruopeng Zhang
1

  1. School of Automation and Electrical Engineering, Lanzhou Jiaotong University, China
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Abstract

This paper proposes a power system stabilizer (PSS) with optimal controller parameters for damping low-frequency power oscillations in the power system. A novel meta-heuristic, weighted grey wolf optimizer (WGWO) has been proposed, it is a variant of the grey wolf optimizer (GWO). The proposed WGWO algorithm has been executed in the selection of controller parameters of a PSS in a multi-area power system. A two-area fourmachine test system has been considered for the performance evaluation of an optimally tuned PSS. A multi-objective function based on system eigenvalues has been minimized for obtained optimal controller parameters. The damping characteristics and eigenvalue location in the proposed approach have been compared with the other state-of-the-art methods, which illustrates the effectiveness of the proposed approach.
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Authors and Affiliations

Murali Krishna Gude
1
ORCID: ORCID
Umme Salma Salma
1
ORCID: ORCID

  1. Gandhi Institute of Technology and Management (GITAM), Visakhapatnam, India
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Abstract

The model predictive current control (MPCC) of the permanent magnet synchronous motor (PMSM) is highly dependent on motor parameters, and a parameter mismatch will cause the system performance degradation. Therefore, a strategy based on an internal model control (IMC) observer is proposed to correct the mismatch parameters. Firstly, based on the MPCC strategy of the PMSM, according to the dynamic model of the PMSM in a rotating orthogonal coordinate system, d-axis and q-axis current IMC observers are designed, and the stability derivation is carried out. It is proved that the observer can estimate d-axis and q-axis disturbance components caused by a parameter mismatch without static error. Then, the estimated disturbance component is compensated for by the reference voltage prediction expression. Finally, the effectiveness of the proposed strategy is verified in two different conditions. The experimental results show that the proposed control strategy can effectively compensate for the parameter mismatch disturbance in MPCC for PMSM, improve the dynamic and static performance of the system, and improve the robustness of the system.
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Authors and Affiliations

Min'an Tang
1
Chenyu Wang
1
Yinhang Luo
1
ORCID: ORCID

  1. School of Automation and Electrical Engineering, Lanzhou Jiaotong University, China No. 88, Anning West Road, Anning District, Lanzhou City, Gansu Province, China
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Abstract

The neutral point clamped (NPC) three-level grid-tied converter is the key equipment connecting renewable energy and power grids. The current sensor fault caused by harsh environment may lead to the split of renewable energy. The existing sensor fault-tolerant methods will reduce the modulation ratio index of the converter system. To ensure continuous operation of the converter system and improve the modulation index, a model predictive control method based on reconstructed current is proposed in this paper. According to the relationship between fault phase current and a voltage vector, the original voltage vector is combined and classified. To maintain the stable operation of the converter and improve the utilization rate of DC voltage, two kinds of fault phase current are reconstructed with DC current, normal phase current and predicted current, respectively. Based on reconstructed three-phase current, a current predictive control model is designed, and a model predictive control method is proposed. The proposed method selects the optimal voltage vector with the cost function and reduces time delay with the current reconstruction sector. The simulation and experimental results showthat the proposed strategy can keep the NPC converter running stably with one AC sensor, and the modulation index is increased from 57.7% to 100%.
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Authors and Affiliations

Yanyan Li
1
ORCID: ORCID
Han Xiao
1
Nan Jin
1
ORCID: ORCID
Guanglu Yang
1 2

  1. College of Electrical and Information Engineering, Zhengzhou University of Light Industry, China
  2. Nanyang Cigarette Factory, China Tobacco Henan Industrial Co., Ltd., China
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Abstract

The discrete Fourier transform (DFT) is the main method of electrical harmonic analysis since it’s easily realized in an embedded system. But there were some difficulties in performing synchronized sampling. The spectral leakage caused by asynchronous sampling affects the accuracy of harmonics analysis. Using window functions and interpolation algorithms can improve the accuracy of harmonics analysis. An approach for electrical harmonic analysis based on the interpolation DFT was proposed. A window function reduces DFT leakage and the interpolation algorithm modifies the calculation results of frequency, amplitude and the initial phase angle. The simulation results indicate that, by using the interpolation DFT electrical harmonic analysis method based on the Hanning window or the Blackman window, the error of calculating amplitudes and frequencies is not greater than 0.5%.
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Authors and Affiliations

Lina Jiao
1
ORCID: ORCID
Yang Du
1

  1. Shandong Polytechnic, China
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Abstract

When the in-wheel motor is working, it will be affected by gravity, centrifugal force and electromagnetic force. These three kinds of mechanical loads will affect the mechanical stress characteristics of the in-wheel motor, and then affect the reliability of the in-wheel motor structure. In order to understand the influence of the above loads on the mechanical stress of the in-wheel motor, this paper takes a 15-kWbuilt-in permanent magnet in-wheel motor as the research object. Based on the establishment of the electromagnetic field and structure field coupling analysis model of the in-wheel motor, the mechanical stress of the in-wheel motor under different mechanical loads under rated and peak conditions are calculated and analyzed, and the influence of different mechanical loads on the stress and deformation of the in-wheel motor are studied. The research results show that, regardless of the rated operating condition or the peak operating condition, the in-wheel motor has the largest mechanical stress and deformation under the combined action of centrifugal force and electromagnetic force, and the smallest mechanical stress and deformation under the action of gravity only; under the same load (except for the case of gravity only), the stress and deformation of the in-wheel motor under the peak operating condition are larger than those under the rated operating condition; and the maximum stress and deformation of the in-wheel motor appear at the rotor magnetic bridge and the inner edge of the rotor, respectively, so the rotor is an easily damaged part of the in-wheel motor.
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Authors and Affiliations

Jie Xu
1
ORCID: ORCID

  1. Shandong University of Technology, School of Transportation and Vehicle Engineering, China
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Abstract

The mismatch effect of photovoltaic (PV) arrays due to different illumination intensity has a significant impact on the output characteristics and output power of PV arrays, which is crucial to understand the output characteristics of PV arrays and optimize the array configuration in order to improve the value of the maximum power point. This paper illustrates the short-circuit current mismatch of series circuits, and the open-circuit voltage mismatch of parallel circuits and proposes corresponding solutions for each mismatch phenomenon. The output characteristics of multi-stage series PV arrays and multi-stage parallel PV arrays under complex illumination are analyzed by using the peak point approximation calculation method, and the distribution law of peak voltage points as well as the I-V (Current-Voltage) characteristic equation of each operating section are proposed. On this basis, the output characteristics of 3 x 3 centralized PV arrays are analyzed and verified by simulation. By comparing series and parallel PV arrays with the same condition, as well as several groups of centralized PV arrays with the same topology and different types of illumination distribution, this paper proposes a configuration optimization method for PV arrays. Matlab/Simulink simulation results confirm that the output power of parallel arrays is greater than that of series arrays under the same configuration and illuminationt distribution type, and the peak point is less than that of series arrays under the same configuration and lighting conditions; while in centralized PV arrays, the fewer series modules are shaded, the greater the output power and the less the peak point.
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Authors and Affiliations

Liming Wei
1
ORCID: ORCID
KaiKai Li
1
ORCID: ORCID

  1. School of Electrical and Computer Engineering, Jilin Jianzhu University, Changchun, Jilin, China
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Abstract

A Computational Intelligence (CI) approach is one of the main trending and potent data dealing out and processing instruments to unravel and resolve difficult and hard reliability crisis and it takes an important position in intelligent reliability analysis and management of data. Nevertheless, just few little broad reviews have recapitulated the current attempts of Computational Intelligence (CI) in reliability assessment in power systems. There are many methods in reliability assessment with the aim to prolong the life cycles of a system, to maximize profit and predict the life cycle of assets or systems within an organization especially in electric power distribution systems. Sustaining an uninterrupted electrical energy supply is a pointer of affluence and nationwide growth. The general background of reliability assessment in power system distribution using computational intelligence, some computational intelligence techniques, reliability engineering, literature reviews, theoretical or conceptual frameworks, methods of reliability assessment and conclusions was discussed. The anticipated and proposed technique has the aptitude to significantly reduce the needed period for reliability investigation in distribution networks because the distribution network needs an algorithm that can evaluate, assess, measure and update the reliability indices and system performance within a short time. It can also manage outages data on assets and on the entire system for quick and rapid decisions making as well as can prevent catastrophic failures. Those listed above would be taken care of if the proposed method is utilized. This overview or review may be deemed as valuable assistance for anybody doing research.
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Authors and Affiliations

Elijah Adebayo Olajuyin
1
ORCID: ORCID
Paul Kehinde Olulope
2
Emmanuel Taiwo Fasina
2

  1. Bamidele Olumilua University of Education, Science and Technology, Ikere Ekiti, Nigeria
  2. Ekiti State University, Ado Ekiti, Nigeria
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Abstract

Complex gaps may be formed when carrying out live working in substations, while the discharge characteristics of complex gaps are different from those of single gaps. This paper focuses on the prediction of critical 50% positive switching impulse breakdown voltage ( U 50–crit + of phase-to-phase complex gaps formed in 220 kV substations. Firstly, several electric field features were defined on the shortest discharge path of the complex gap to reflect the electric field distribution. Then support vector machine (SVM) prediction models were established according to the connection between electric field distribution and breakdown voltage. Finally, the U 50–crit¸+ data of the complex gap were obtained through twice electric field calculations and predictions. The prediction results show that the minimum U 50–crit + of phase-to-phase complex gaps is 1147 kV, and the critical position is 0.9 m away from the high voltage conductor, accounting for 27% of the whole gap. Both critical position and voltage are in good agreement with the values provided in IEC 61472.
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Authors and Affiliations

Zhenpeng Tang
1
Yuancheng Qin
2
ORCID: ORCID
Changsheng Wu
1
Ronghuan Mai
1

  1. Jiangmen Power Supply Bureau Co., Ltd., China
  2. School of Automation, Wuhan University of Technology, China
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Abstract

The aim of the considerations presented in the article was a stand-alone groundbased photovoltaic power plant. The article is devoted to the qualitative analysis of some lightning protection configurations. These types of constructions often require an individual look at the design and execution of lightning protection installations, which causes problems with the selection of optimal solutions. These problems relate primarily to the way the lightning rods are arranged to create protection zones, but also to the way they are attached: to the supporting structure for PV modules or as free-standing. Another problem raised in the article is the way how lightning current is discharged from rods to the ground and how it is dispersed there. Due to the vast area of such facilities and the requirements for electrical safety, it is necessary to consider and design a ground system with optimal electrical parameters, but also technical and economic ones. All these elements have their impact on the value of voltages induced in the electrical installation, which is also presented in the content of the article as the magnetic field distribution and calculation of induced voltages in an exemplary configuration. Finally, this article will compare described technical solutions encountered in selecting the best protection method for this type of photovoltaic installation.
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Authors and Affiliations

Konrad Sobolewski
1
ORCID: ORCID
Emilia Sobieska
1
ORCID: ORCID

  1. Warsaw University of Technology, Faculty of Electrical Engineering, Poland
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Abstract

The development in industrial systems leads to the augmentation in the consumption of the power. Therefore, this development makes use of multiphase machines. The use of multiphase machines caused several problems and defects. Electrical energy is mainly distributed in a three-phase system to provide the electrical power necessary for the electrical engineering equipment and materials. The sinusoidal aspect of the required original voltage primarily preserves its essential qualities for transmitting useful power to terminal equipment. When the voltage waveform is no longer sinusoidal, perturbations are encountered, which generate malfunctions and overheating of the receivers and the equipment connected to the same electrical supply network. The main disturbing phenomena are harmonics, voltage fluctuations, voltage unbalances, electromagnetic fields, and electrostatic discharges. This present work aims to study the effects of harmonic pollution and voltage unbalance on the five-phase permanent magnet synchronous machine using spectrum current analysis and wavelet transform.
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Authors and Affiliations

Ahmed Amine Kebir
1
ORCID: ORCID
Mouloud Ayad
1
ORCID: ORCID
Saoudi Kamel
1
ORCID: ORCID

  1. LPM3E Laboratory, Faculty of Sciences and Applied Sciences, University of Bouira, Algeria
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Abstract

Diode neutral point clamped (NPC) three-level converters have been widely used in recent years. Aiming at the problems of the high device failure rate and unstable neutral point potential of NPC three-level converters, an NPC three-level circuit with fourth bridge arm redundancy is proposed based on the traditional NPC three-level converter. The redundant fourth bridge arm is used to realize the function of stabilizing voltage when there is no fault and replacing the fault half-bridge arm to maintain the continuous operation of the converter when there is a fault. By analyzing the working principle of space vector pulse width modulation (SVPWM) and the power loss of the switch, it is of particular significance to the design and control of NPC three-level converters in the future. Matlab/Simulink verifies the feasibility of the fault-tolerant circuit structure.
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Authors and Affiliations

Baoge Zhang
1
ORCID: ORCID
Shanyan Ping
1
Yi Long
1
Yuemin Jiao
1
Boxiang Wu
1

  1. School of Automation and Electrical Engineering, Lanzhou Jiaotong University, China

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