• Title, Summary, Keyword: Reduced number of components

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A Reduced Complexity Decoding Scheme for Trellis Coded Modulation

  • Charnkeitkong, Pisit;Laopetcharat, Thawan
    • Proceedings of the IEEK Conference
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    • pp.2039-2042
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    • 2002
  • In this paper, we propose a technique used to simplify the trellis diagram, thus, reduce the complexity of Viterbi decoder in term of the number of Compare-Select (CS) operations needs in decoding process. It is shown that if the branch metrics are properly decomposed into orthogonal components. The trellis diagram can be modified that each original state with large number branches terminating to it can be broken into a number of sub-states having smaller number of branches terminating to them. Simulation results shown that the newly proposed technique can be used reduced the complexity of 8 and 16 PSK-TCMs without degrading the BER performance.

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Performance Analysis of a Novel Reduced Switch Cascaded Multilevel Inverter

  • Nagarajan, R.;Saravanan, M.
    • Journal of Power Electronics
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    • v.14 no.1
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    • pp.48-60
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    • 2014
  • Multilevel inverters have been widely used for high-voltage and high-power applications. Their performance is greatly superior to that of conventional two-level inverters due to their reduced total harmonic distortion (THD), lower switch ratings, lower electromagnetic interference, and higher dc link voltages. However, they have some disadvantages such as an increased number of components, a complex pulse width modulation control method, and a voltage-balancing problem. In this paper, a novel nine-level reduced switch cascaded multilevel inverter based on a multilevel DC link (MLDCL) inverter topology with reduced switching components is proposed to improve the multilevel inverter performance by compensating the above mentioned disadvantages. This topology requires fewer components when compared to diode clamped, flying capacitor and cascaded inverters and it requires fewer carrier signals and gate drives. Therefore, the overall cost and circuit complexity are greatly reduced. This paper presents modulation methods by a novel reference and multicarrier based PWM schemes for reduced switch cascaded multilevel inverters (RSCMLI). It also compares the performance of the proposed scheme with that of conventional cascaded multilevel inverters (CCMLI). Simulation results from MATLAB/SIMULINK are presented to verify the performance of the nine-level RSCMLI. Finally, a prototype of the nine-level RSCMLI topology is built and tested to show the performance of the inverter through experimental results.

A Cascaded Modular Multilevel Inverter Topology Using Novel Series Basic Units with a Reduced Number of Power Electronic Elements

  • Barzegarkhoo, Reza;Vosoughi, Naser;Zamiri, Elyas;Kojabadi, Hossein Madadi;Chang, Liuchen
    • Journal of Power Electronics
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    • v.16 no.6
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    • pp.2139-2149
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    • 2016
  • In this study, a new type of cascaded modular multilevel inverters (CMMLIs) is presented which is able to produce a considerable number of output voltage levels with a reasonable number of components. Accordingly, each series stage of the proposed CMMLI is comprised of two same basic units that are connected with each other through two unidirectional power switches without aiming any of the full H-bridge cells. In addition, since the potentiality for generating a higher number of output voltage levels in CMMLIs hinges on the magnitude of the dc voltage sources used in each series unit, in the rest of this paper, four different algorithms for determining an appropriate value for the dc sources' magnitude are also presented. In the following, a comprehensive topological analysis between some CMMLI structures reported in the literature and proposed structure along with several simulation and experimental results will be also given to validate the lucrative benefits and viability of the proposed topology.

A Single-Phase Hybrid Multi-Level Converter with Less Number of Components

  • Kim, Ki-Mok;Moon, Gun-Woo
    • Proceedings of the KIPE Conference
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    • pp.105-107
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    • 2018
  • This paper presents a new hybrid multilevel converter topology, which consists of a combination of the series connected switched capacitor units with boost ability, and an H-bridge with T-type bidirectional switches. The proposed converter boosts the input voltage without any bulky inductors, and has the small number of components, which can make the size and cost of a power converter greatly reduced. The output filter size and harmonics are also reduced by the high quality multilevel output. In addition, there is no need for complicated methods to balance the capacitor voltage. Simulation and experimental results with a nine-level converter system are presented to validate the proposed topology and modulation method.

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Advanced Cascade Multilevel Converter with Reduction in Number of Components

  • Ajami, Ali;Oskuee, Mohammad Reza Jannati;Mokhberdoran, Ataollah;Khosroshahi, Mahdi Toupchi
    • Journal of Electrical Engineering and Technology
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    • v.9 no.1
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    • pp.127-135
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    • 2014
  • In this paper a novel converter structure based on cascade converter family is presented. The suggested multilevel advanced cascade converter has benefits such as reduction in number of switches and power losses. Comparison depict that proposed topology has the least number of IGBTs among all multilevel cascade type converters which have been introduced recently. This characteristic causes low cost and small installation area for suggested converter. The number of on state switches in current path is less than conventional topologies and so the output voltage drop and power losses are decreased. Symmetric and asymmetric modes are analyzed and compared with conventional multilevel cascade converter. Simulation and experimental results are presented to illustrate validity, good performance and effectiveness of the proposed configuration. The suggested converter can be applied in medium/high voltage and PV applications.

Effect of Ethanol Concentration on Extraction of Vlolatile Components in Cinnamon (에탄올의 농도가 계피가 향기성분 용출에 미치는 영향)

  • 김나미;김영희
    • The Korean Journal of Food And Nutrition
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    • v.13 no.1
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    • pp.45-52
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    • 2000
  • In order to select the optimum ethanol concentration for extraction of volatile components in cinnamon, the dried cinnamon was extracted with water and 30∼90% ethanol. The volatile components of cinnamon extracts were isolated by the simultaneous distillation extraction method using Likens and Nickerson's extraction apparatus, and analyzed by GC-MS. In cinnamon bark powder 45 components were detected and 21 components were identified. The major component of cinnamon bark powder was cinnamic aldehyde. In water extract of cinnamon, volatile components were not extracted sufficiently. The volatile components of cinnamon were increased with the increment of ethanol concentraction upto 70%. The volatile component of 70% ethanol extract showed similar pattern and amount to cinnamon bark powder. But in 90% ethanol extracts, the number and amount of volatile component were reduced. The above data suggested that 70% ethanol was the most effective solvent for volatile components extraction of cinnamon.

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Gaussian Density Selection Method of CDHMM in Speaker Recognition (화자인식에서 연속밀도 은닉마코프모델의 혼합밀도 결정방법)

  • 서창우;이주헌;임재열;이기용
    • The Journal of the Acoustical Society of Korea
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    • v.22 no.8
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    • pp.711-716
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    • 2003
  • This paper proposes the method to select the number of optimal mixtures in each state in Continuous Density HMM (Hidden Markov Models), Previously, researchers used the same number of mixture components in each state of HMM regardless spectral characteristic of speaker, To model each speaker as accurately as possible, we propose to use a different number of mixture components for each state, Selection of mixture components considered the probability value of mixture by each state that affects much parameter estimation of continuous density HMM, Also, we use PCA (principal component analysis) to reduce the correlation and obtain the system' stability when it is reduced the number of mixture components, We experiment it when the proposed method used average 10% small mixture components than the conventional HMM, When experiment result is only applied selection of mixture components, the proposed method could get the similar performance, When we used principal component analysis, the feature vector of the 16 order could get the performance decrease of average 0,35% and the 25 order performance improvement of average 0.65%.

Reduction of Components in Cascaded Transformer Multilevel Inverter Using Two DC Sources

  • Banaei, Mohamad Reza;Salary, Ebrahim;Alizadeh, Ramin;Khounjahan, Hossein
    • Journal of Electrical Engineering and Technology
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    • v.7 no.4
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    • pp.538-545
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    • 2012
  • In this paper a novel cascaded transformer multilevel inverter is proposed. Each basic unit of the inverter includes two DC sources, single phase transformers and semiconductor switches. This inverter, which operates as symmetric and asymmetric, can output more number of voltage levels in the same number of the switching devices. Besides, the number of gate driving circuits is reduced, which leads to circuit size reduction and lower power consumption in the driving circuits. Moreover, several methods to determination of transformers turn ratio in proposed inverter are presented. Theoretical analysis, simulation results using MATLAB/SIMULINK and experimental results are provided to verify the operation of the suggested inverter.

A New Design for Cascaded Multilevel Inverters with Reduced Part Counts

  • Choupan, Reza;Nazarpour, Daryoush;Golshannavaz, Sajjad
    • Transactions on Electrical and Electronic Materials
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    • v.18 no.4
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    • pp.229-236
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    • 2017
  • This paper deals with the design and implementation of an efficient topology for cascaded multilevel inverters with reduced part counts. In the proposed design, a well-established basic unit is first developed. The series extension of this unit results in the formation of the proposed multilevel inverter. The proposed design minimizes the number of power electronic components including insulated-gate bipolar transistors and gate driver circuits, which in turn cuts down the size of the inverter assembly and reduces the operating power losses. An explicit control strategy with enhanced device efficiency is also acquired. Thus, the part count reductions enhance not only the economical merits but also the technical features of the entire system. In order to accomplish the desired operational aspects, three algorithms are considered to determine the magnitudes of the dc voltage sources effectively. The proposed topology is compared with the conventional cascaded H-bridge multilevel inverter topology, to reflect the merits of the presented structure. In continue, both the analytical and experimental results of a cascaded 31-level structure are analyzed. The obtained results are discussed in depth, and the exemplary performance of the proposed structure is corroborated.

Development of a Switched Diode Asymmetric Multilevel Inverter Topology

  • Karthikeyan, D.;Krishnasamy, Vijayakumar;Sathik, Mohd. Ali Jagabar
    • Journal of Power Electronics
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    • v.18 no.2
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    • pp.418-431
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    • 2018
  • This paper presents a new asymmetrical multilevel inverter with a reduced number of power electronic components. The proposed multilevel inverter is analyzed using two different configurations: i) First Configuration (with a switched diode) and ii) Second Configuration (without a switched diode). The presented topologies are compared with recent multilevel inverter topologies in terms of number of switches, gate driver circuits and blocking voltages. The proposed topologies can be cascaded to generate the maximum number of output voltage levels and they are suitable for high voltage applications. Various power quality issues are addressed for both of the configurations. The proposed 11-level inverter configuration is simulated using MATLAB and it is validated with a laboratory based experimental setup.