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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

This paper presents a systematic thermogravimetric (TG) study on the kinetics of end-of-life tyre (ELT) pyrolysis. In the experimental part of this work, TG results are compared for tyre samples of different mass and size. This shows that the conduction resistance in the milligram scale (up to ~100 mg) tyre sample can be neglected. A comparison of experimental results demonstrates that the characteristic maxima on the DTG curve (the first derivative of TG signal) shift towards higher temperatures for higher heating rates. This phenomenon is explained to have kinetic origin and it is not caused by the internal heat transfer resistance. In the modelling part of this work, the kinetic parameters of the Three-Component Simulation Model (TCSM) are calculated and compared to the literature values. Testing of the kinetic model is carried out using experiments with a varying heating rate. This shows the limitation of the simplified kinetic approach and the appropriate selection method of the kinetic parameters.

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Authors and Affiliations

Robert Cherbański
Eugeniusz Molga
Krzysztof Wróblewski
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Abstract

Rapid Visual Screening (RVS) method for buildings was originally developed by the Applied Technology Council (ATC) in the late 1980’s for potential seismic hazards. This is a simple and almost a quick way of assessing the building seismic vulnerability score based on visual screening. The logarithmic relationship between final score and the probability of collapse at the maximum considered earthquake (MCE) makes results somewhat difficult to interpret, especially for less technical users. This study is developed to improve the simplicity and usefulness of RVS methodology to determine the numeric scores for seismic vulnerability of buildings using vulnerability functional form. The proposed approach applies the existing method in FEMA 154 (2002) for calculating the building rank based on RVS method. In this study RVS scores are used to evaluate populations of buildings to prioritize detailed evaluations and seismic retrofits. The alternate non-logarithmic format of scoring scheme is much better meeting the needs of the project managers and decision makers, as they require results that are easier to understand. It shows the linear equivalent of RVS final scores which is consistent with the existing ranking systems used in the buildings management program such as budget allocation decision making. The results demonstrate that the weight determined for the factor of “Region Seismicity”, which is 0.4033, has the highest contribution to seismic vulnerability scores of buildings. The applicability of the proposed method is demonstrated through a hypothetical example to rank ten seismically vulnerable buildings.

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Authors and Affiliations

Mohammadreza Yadollahi
Azlan Adnan
Rosli Mohamad Zin

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