직교변조 시스템을 위한 복소 에스컬레이터 Equalizer

김남용 대한전자공학회 2004 電子工學會論文誌-TC (Telecommunications) Vol.41 No.7

에스컬레이터 (ESC) 구조의 장점인 완잔 직교화 성질을 복소 채널 Equalization 및 직교변조방식의 Equalization에 적용할 수 있도록 하기 위해 ESC 구조에 복소연산을 적용함으로서 복소 ESC 구조 Equalizer를 설계하였다. 고유치 분포비가 크게 다른 채널 모델에 대한 복소 Equalizer 들의 수렴성능을 비교해 본 결과 고유치 분포비 (ESR) 값이 증가에 따라 수렴속도에 있어서 제안한 복소 ESC Equalizer는 영향을 받지 않았다. 또한 QPSK 전송-복소 채널 모델에 대하여도 시뮬레이션을 시행한 결과 기존의 복소 TDL-LMS 보다 약 7 배의 빠른 수렴을 보여 제안한 복소 ESC Equalizer의 우수한 특성을 확인할 수 있다. In this paper we introduce a complex escalator (ESC) structure-Equalizer and investigate its performance in complex channels in QPSK undulation systems. The proposed complex equalizer has the complete orthogonalization property and is independent of eigenvalue spread ratio (ESR) of channel. The proposed complex ESC equalizer shows as 7 times faster convergence speed as that of the conventional complex TDL equalizer algorithms in a complex channel model for QPSK systems.

Simulation of load lifting with equalizers used in shipyards

Ham, S.H.,Roh, M.I.,Lee, H. Elsevier ; Elsevier Science Pub. Co 2016 AUTOMATION IN CONSTRUCTION - Vol.61 No.-

One of the most commonly used pieces of equipment for lifting a load is the equalizer of a crane in shipbuilding production. The equalizer distributes the tension in wire ropes between the load and equipment equally. While the equalizer is composed simply of several fixed and moving pulleys, the mechanism of an equalizer is not easy to adapt to physics-based simulations because only one wire rope is coiled around all of the pulleys. Thus, instead of the real mechanism of the equalizer, an alternative mechanism, such as stretching or shortening the initial lengths of the wire ropes, logically, has been used in previous simulations. In this study, a mass-less constraint-based wire rope is adopted to realize the real mechanism of the equalizer. The constant length constraint is used to realize one wire rope among the fixed and moving equalizer pulleys. We derive a discrete Euler-Lagrange (DEL) equation to represent the motion of a multibody system including the constraint wire ropes. The DEL equation is shown to be numerically stable for the case of linear holonomic constraints, such as the constant length constraint. We test several series of fixed and moving pulleys and model the equalizer based on the real mechanism. Finally, the equalizer based on the real mechanism is applied to two typical lifting cases in shipbuilding production. One is lifting a load using a Goliath crane with three equalizers and the other is to use a floating crane with one equalizer and two crawler cranes. As a result, the tensions in the wire ropes connected to the load are adjusted equally as the position of the moving pulleys and the orientation of the equalizer change.

Current Sensorless Single-Switch Voltage Equalizer Using Multi-Stacked Buck-Boost Converters for Photovoltaic Modules under Partial Shading

M. Uno,A. Kukita 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Differential power processing converters or voltage equalizers have been proposed and used for photovoltaic (PV) string comprising multiple modules/substrings connected in series in order to preclude negative influences of partial shading. The single-switch voltage equalizer using multi-stacked buck-boost converters can significantly reduce the necessary switch count compared to that of conventional topologies, achieving simplified circuitry. However, multiple current sensors are necessary for this single-switch equalizer to effectively perform equalization. In this paper, a current sensorless equalization technique, ΔV-controlled equalization, is presented. An equalization strategy using the ΔV-controlled equalization is explained and discussed on the basis of comparison with other equalization strategies. Experimental equalization tests emulating partial-shading conditions were performed using the single-switch equalizer employing the ΔV-controlled equalization. Negative impacts of partialshading were successfully precluded, demonstrating the efficacy of the proposed ΔV-controlled equalization strategy.

가중평균 볼테라 커널을 이용한 아날로그-디지털 변환기의 블라인드 비선형 등화기 설계

박성문,안철진,김형우,서원기,최준영 한국정보기술학회 2014 한국정보기술학회논문지 Vol. No.

We propose a new method to design a blind nonlinear equalizer to improve the performance of ADC(Analog-to-Digital Converter) by using a weighted averaged Volterra kernels. We employ the structure of the existing blind equalizer using Volterra series for the basic structure of the designed equalizer. While the Volterra kernels are determined from output signals driven by Gaussian input signals in the existing methods, the Volterra kernels are determined by weightedly averaging a set of Volterra kernels obtained from several single-tone input signals. Consequently, the proposed method enables to design an equalizer without additional experiments for Gaussian signals when ADC’s outputs are available for several single-tone input signals. Applying the designed equalizer to a real ADC model and conducting experiments, we confirm that the equalizer adequately compensates the nonlinearity of ADC. Moreover, comparing the experiment results to those from an existing blind equalizer, we verify that the designed equalizer achieves a similar performance to the existing equalizer. 본 논문에서는 가중평균 볼테라 커널을 이용하여 ADC(Analog-to-Digital Converter)의 성능을 향상시키기 위한 블라인드 비선형 등화기를 설계하는 방법을 제안한다. 설계된 등화기의 기본 구조로는 볼테라 급수를 이용하는 기존의 블라인드 비선형 등화기 구조를 채택한다. 기존에 제안된 방법은 가우시안 입력 신호에 대한 출력을 이용하여 최종 볼테라 커널을 산출하지만, 본 논문에서는 단일 톤에 대한 출력을 바탕으로 가중평균을 계산하여 최종 볼테라 커널을 산출한다. 이와 같은 방법을 통하여 단일 톤에 대한 ADC의 출력을 알고 있을 경우 새로운 가우시안 입력에 대한 실험값 없이도 등화기를 설계하는 것이 가능하게 된다. 제안된 방법에 따라 설계된 등화기를 실제 ADC 모델에 적용하여 실험을 수행하여 비선형성을 적절히 보상하는 것을 확인하고 기존 등화기에 대한 실험 결과와 비교하여 유사한 성능을 보장하는 것을 검증한다.

A Modularized Equalizer for Supercapacitor Strings in Hybrid Energy Storage Systems

Gao, Zhigang,Jiang, Fenlin The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4

In hybrid energy storage systems, supercapacitors are usually connected in series to meet the required voltage levels. Equalizers are effective in prolonging the life of hybrid energy storage systems because they eliminate the voltage imbalance on cells. This study proposes a modularized equalizer, which is based on a combination of a half-bridge inverter, an inductor, and two auxiliary capacitors. The proposed equalizer inherits the advantages of inductor-based equalization systems, but it also offers unique merits, such as low switching losses and an easy-to-use control algorithm. The zero-voltage switching scheme is analyzed, and the power model is established. A fixed-frequency operation strategy is proposed to simplify the control and lower the cost. The switching patterns and conditions for zero-voltage switching are discussed. Simulation results based on PSIM are presented to verify the validity of the proposed equalizer. An equalization test for two supercapacitor cells is performed. An experimental hybrid energy storage system, which consists of batteries and supercapacitors, is established to verify the performance of the proposed equalizer. The analysis, simulation results, and experimental results are in good agreement, thus indicating that the circuit is practical.

A Modularized Equalizer for Supercapacitor Strings in Hybrid Energy Storage Systems

Zhigang Gao,Fenlin Jiang 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4

In hybrid energy storage systems, supercapacitors are usually connected in series to meet the required voltage levels. Equalizers are effective in prolonging the life of hybrid energy storage systems because they eliminate the voltage imbalance on cells. This study proposes a modularized equalizer, which is based on a combination of a half-bridge inverter, an inductor, and two auxiliary capacitors. The proposed equalizer inherits the advantages of inductor-based equalization systems, but it also offers unique merits, such as low switching losses and an easy-to-use control algorithm. The zero-voltage switching scheme is analyzed, and the power model is established. A fixed-frequency operation strategy is proposed to simplify the control and lower the cost. The switching patterns and conditions for zero-voltage switching are discussed. Simulation results based on PSIM are presented to verify the validity of the proposed equalizer. An equalization test for two supercapacitor cells is performed. An experimental hybrid energy storage system, which consists of batteries and supercapacitors, is established to verify the performance of the proposed equalizer. The analysis, simulation results, and experimental results are in good agreement, thus indicating that the circuit is practical.

복소 쌍선형 회귀신경망의 개발과 비선형 위성채널 등화

정태균,박동철 명지대학교 대학원 1999 대학원논문집 Vol.3 No.-

Equalization of satellite communication using Complex-Bilinear Recurrent Neural Network(C-BLRNN) is proposed in this paper. Since the BLRNN is based on the bilinear polynomial it has been more effectively used in modeling highly nonlinear systems with time-series characteristics than multi-layer perceptron type neural networks(MLPNN). The BLRNN is first expanded to its complex value version(C-BLRNN) for dealing with the complex input values C-BLRNN is then applied to equalization of a digital satellite communication channel for M-PSK and QAM, which has severe nonlinearity with memory due to TWTA(Traveling Wave Tube Amplifier). The proposed C-BLRNN based equalizer for a channel model is compared with currently used Volterra filter Equalizer. DFE, and conventional Complex MLPNN Equalizer. The results show that the proposed C-BLRNN based equalizer gives very favorable results in both of MSE and BER criteria over Volterra filter Equalizer, DFE, and Complex MLPNN Equalizer.

비트 패턴 미디어 저장장치를 위한 축약사상 기반의 반복적 2차원 등화기

문우식(Woosik Moon),임성빈(Sungbin Im),박세황(Sehwang Park) 대한전자공학회 2013 전자공학회논문지 Vol.50 No.6

Adaptive Equalization for DS-CDMA Multi-User Communication System Using Laguerre Filters

T. Somkur,C. Benjangkaprasert 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

In this paper proposes an adaptive equalizer using Laguerre transversal filter and a RLS algorithm for adaptation in DS-CDMA mobile communication systems. The Laguerre structure is compromise between the FIR and IIR structures, since the Laguerre structure is always stable. We also analyze the Bit Error Rate (BER) performance of the proposed equalizer and the conventional equalizer. The simulation results show that the performances of the proposed equalizer are better than the conventional equalizer, such as fast convergence and lower BER than the conventional adaptive equalizer for every E0 / Nb value.

Gain Equalizer by Four Parameters Logistic Bézier Bernstein Polynomial

Isoon Kanjanasurat,V. Chutchavong,C. Benjankaprasert,K. Janchitrapongvej 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.1

This paper presents the design gain equalizer base on using Bernstein polynomial and rational bézier-bernstein with four parameters logistic curve that four parameters can adjust the characteristic of gain Equalizer. +/- 1dB Gain Equalizer which is used to set the feature. In result, The Equalizer has simulated the equalizer using Bernstein polynomial have order 100 and rational bézier-bernstein have order 4. Moreover, phase and delay of the equalizer are zero.