The Research of the V-I Characteristics of a Solar Panel Using a Computerized Measuring Bench “EPH 2 Advanced Photovoltaics Trainer”
Mirzayev Uchqun,
Tulakov Jahongir
Issue:
Volume 7, Issue 3, June 2019
Pages:
79-83
Received:
19 February 2019
Accepted:
28 March 2019
Published:
16 August 2019
Abstract: At present, much attention is paid to the use of solar energy. Solar energy, in addition to traditional energy, is ecologically clean while changing. The rarity and the rising cost of fuel is one of the main problems of the scientific technique, which is the acquisition of infinite resources of solar energy. Further research and experiments on the use of solar energy, as well as the use of solar power plants in a number of countries, shows that solar energy can be widely used today based on modern technical capacities. In order to determine the need to use a charger, it is necessary to know a number of parameters: short circuit current, no-load voltage, efficiency, etc. In this work, these parameters are estimated from the results of studies of the current-voltage characteristic of a solar panel obtained in automatic mode using a computer and digital measuring device "EPH 2 Advanced photovoltaics trainer".
Abstract: At present, much attention is paid to the use of solar energy. Solar energy, in addition to traditional energy, is ecologically clean while changing. The rarity and the rising cost of fuel is one of the main problems of the scientific technique, which is the acquisition of infinite resources of solar energy. Further research and experiments on the ...
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Synthesis of Hurwitz Polynomial Families Using Root Locus Portraits
Alla Anatolyevna Nesenchuk
Issue:
Volume 7, Issue 3, June 2019
Pages:
84-91
Received:
10 August 2019
Accepted:
16 September 2019
Published:
27 September 2019
Abstract: The paper deals with the problem of synthesis of a stable characteristic polynomial families describing the control systems' dynamics in conditions of the interval uncertainty. Investigation is based on the system mathematical model in the form of its root locus portrait generated by the polynomial free term variation that is named in the paper as the "free root locus portrait". The root loci of the Kharitonov's polynomials family (subfamily) is picked out of the whole polynomial family and is considered for carrying out the investigation. Specific regularities of the interval root locus portrait have been discovered. On the basis of these regularities main properties of the system root locus portrait have been defined. A stability condition has been formulated that allows to calculate the polynomial free term variation interval ensuring the polynomial family hurwitz stability. This stability condition is applicable to the class of polynomials having their free root locus poles lying within the left half-plane of roots or, in other words, being stable when their free term is equal to zero. The stable family is being synthesized by setting up (adjusting) the given initial family that is supposed to be unstable, i.e. the proposed method of synthesis allows to turn stable (hurwitz) the given nonhurwitz interval polynomial family. The setting up criterion is specified in terms of proximity i.e. as the nearest distance from the "unstable" system roots to the "stable" ones as measured along the root trajectories. The stable polynomial could be selected as the nearest to the given unstable one with or without consideration of the system quality requirements. In the course of the setting up procedure new boundaries of only the polynomial free term variation interval (stability interval) are calculated that allows to ensure system stability without modification of its root locus portrait configuration. A numerical example of the polynomial setting up procedure has been given.
Abstract: The paper deals with the problem of synthesis of a stable characteristic polynomial families describing the control systems' dynamics in conditions of the interval uncertainty. Investigation is based on the system mathematical model in the form of its root locus portrait generated by the polynomial free term variation that is named in the paper as ...
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Improved Wiener Filter Algorithm for Speech Enhancement
Zhao Yanlei,
Ou Shifeng,
Gao Ying
Issue:
Volume 7, Issue 3, June 2019
Pages:
92-98
Received:
15 October 2019
Published:
18 November 2019
Abstract: Most of the existing speech enhancement algorithms are aimed at improving the quality of speech, and the algorithms that can improve the speech intelligibility effectively are rare. Speech intelligibility has been found to improve listening comfort and it is generally related to the distortion of the speech signal closely. Studies have assessed the impact of speech distortion introduced by gain functions and shown that one of the main reasons that existing algorithms cannot improve speech intelligibility is because they allow amplification distortions more than 6dB. Therefore, these distortions of the enhanced amplitude spectrum should be corrected to improve the speech intelligibility. The early research by Loizou et al. obtained the experimental results on the ideal state and we are unable to use it in reality because there is no clean speech in reality. In this paper, we modify the method proposed by Loizou et al. and select the estimated speech under two hypothetical conditions to verify the improvement of the speech intelligibility. The short-term objective intelligibility value verifies the improvement of speech intelligibility as the improved algorithm of speech intelligibility is applied to reality successfully.
Abstract: Most of the existing speech enhancement algorithms are aimed at improving the quality of speech, and the algorithms that can improve the speech intelligibility effectively are rare. Speech intelligibility has been found to improve listening comfort and it is generally related to the distortion of the speech signal closely. Studies have assessed the...
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