• Title/Summary/Keyword: Waveform control

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On a Pitch Alteration Method by Time-axis Scaling Compensated with the Spectrum for High Quality Speech Synthesis (고음질 합성용 스펙트럼 보상된 시간축조절 피치 변경법)

  • Bae, Myung-Jin;Lee, Won-Cheol;Im, Sung-Bin
    • The Journal of the Acoustical Society of Korea
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    • v.14 no.4
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    • pp.89-95
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    • 1995
  • The waveform coding technique has concerned with simply preserving the waveform shape of speech signal through a redundancy reduction process. In the case of speech synthesis, the waveform coding with high sound quality is mainly used to the synthesis by analysis. However, since the parameters of this coding are not classified into either excitation or vocal tract parameters, it is difficult to applying the waveform coding to the synthesis by rule. In order to apply the waveform coding to the synthesis by rule, the pitch alteration technique is required in prosody control. In this paper, we propose a new pitch alteration method that can change the pitch period in waveform coding by scaling the time-axis and compensating the spectrum. This is relevant to the time-frequency domain method were the phase components of the waveform is preserved with a little spectrum distortion of 2.5 % and less for 50% pitch change.

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Characteristic Comparison between PI and Hysteresis Voltage Control of High Voltage Unidirectional Inverter for Piezoelectric Load using FPGA (FPGA를 이용한 피에조 부하 구동용 고전압 단방향 인버터의 PI 및 히스테리시스 전압 제어 특성 비교)

  • Kim, Ki-Seok;Cho, Yong-Ho;Kim, Hyeong-Seop;Kang, Tae-Sam;Hong, Sun-Ki
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.1
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    • pp.48-54
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    • 2017
  • In this paper, hysteresis voltage control method is proposed to an unidirectional inverter control for piezoelectric load. Piezoelectric load has electrically RC characteristic, and is driven by the inverter to control the output voltage waveform. When controling the output waveform by PI control, appropriate gains need to be selected. However, hysteresis control may minimize the output distortion because it has maximum proportional gain. In addition, Hysteresis control algorithm has simple structure to realize and the response is fast. Although the switching frequency of the inverter by hysteresis control varies, the switching frequency for the piezoelectric load is lower than that by PI control for equivalent performance. In particular, on implementing the algorithm using FPGA, the algorithm can be implemented in fewer pabrics and the processing time can be reduced. The superiority of the proposed hysteresis voltage control was proved for piezoelectric load through simulation and experiment.

Development of Algorithm of Surge Test for Quality Control on Electrical Parts of Throttle Body in Automobiles (차량 드로틀 보디 전장부품의 품질관리 성능시험 알고리즘 개발)

  • Son, Jae-Hwan;Kim, Tae-Han
    • Journal of the Korean Society of Industry Convergence
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    • v.9 no.1
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    • pp.67-72
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    • 2006
  • This study is on the development of algorithm of surge test for quality control on electrical parts of throttle body in automobiles with internal combustion engine, not only to know its condition to be good or not, but also jugding its condition to be classified into six types. To know whether its condition to be good or not, comparing and analyzing between two waveforms generated from master and test coil of throttle body. If test net area is below 20% of master area, the condition of test coil is good. By analyzing test coil waveform to master coil waveform, the condition of test coil into winding badness, insulation badness, layer and corona discharge, short badness should known. Therefore quality control system on electrical parts of throttle body should be developed.

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Development of a stroke output control algorithm using a fuzzy logic for a left ventricular assist device

  • Choi, Jae-Soon;Choi, Won-Woo;Park, Seong-Keun;Park, Seong-Keun;Min, Byoung-Goo
    • 제어로봇시스템학회:학술대회논문집
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    • 1995.10a
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    • pp.514-517
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    • 1995
  • A new stroke output control algorithm with a fuzzy logic for an electrohydraulic left ventricular assist device(EH-LVAD) was developed. The EH-LVAD pumps out blood from left atrium actively. Excessive suction of blood may cause fatal damage in left atrium. The LVAD has to provide a maximal stroke output without collapse of left atrium. In this study a new fuzzy algorithm for predicting and detecting suction and doing proper action on LVAD without using an extra pressure sensor but with bellows pressure signal and motor current signal is developed. The performance of the fuzzy control algorithm is demonstrated by the results from mock circulatory experiments.

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A Study on the Analysis of the Output Waveform of Three-Phase Regular Sampling PWM Inverter (3상 레귤러 샘플링 PWM 인버터의 출력파행 분석에 관한 연구)

  • 노창주
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.28 no.3
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    • pp.274-285
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    • 1992
  • Among various Power converters, a variable voltage variable frequency (VVVF) three-phase PWM inverter is regarded as most promising power converter due to its capabilities, which permits the control of voltage, frequency and harmonic contents in a single power stage employing only on DC source. As a modulating technique of the PWM inverter, the regular sampling technique has rendered possible the on-line computation and generation of PWM control waveforms with a reasonably high switching frequencies. In this paper, microprocessor based three-phase regular samping PWM inverter with real-time control algorithm and control circuits for driving three phase AC motor has been developed. Harmocic components of PWM waveform were analized theoretically in terms of Bessel function series and then calculated by digital computer and observed with spectrum analyzer.

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Power Density Maximization of the Brushless DC Generator by Controlling the Optimal Current Waveform (최적 전류파형제어를 통한 브러시리스 DC 발전기의 출력밀도 최대화에 관한 연구)

  • 이형우
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.7
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    • pp.430-436
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    • 2004
  • This paper presents an advanced control technique for power density maximization of the Brushless DC (BLDC) generator by using the linear tracking method. In a generator of given rating, the weight and size of the system affect the fuel consumption directly. Therefore, power density is one of the most important issues in a stand-alone generator. BLDC generator has high power density in the machine point of view and additional increases of power density by control means can be expected. Conventional rectification methods cannot achieve the maximum power possible because of hon-optimal current waveforms. The optimal current waveform to maximize power density and minimize machine size and weight in a nonsinusoidal power supply system has been derived, incorporated in a control system, and verified by simulation and experimental work. A new simple algebraic method has been proposed to accomplish the proposed control without an FFT which is time consuming and complicated.

Study of Harmonic Sources Management Method using Control Chart (컨트롤 차트를 이용한 고조파 전압 왜곡 발생원 관리기법 연구)

  • Han, Jong-Hoon;Lee, Key-Byung;Jang, Gil-Soo;Park, Chang-Hyun
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.197-198
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    • 2011
  • A technique to manage harmonic pollution at the point of common coupling (PCC) has been presented using a control chart. The recursive least-squares technique has been used to estimate the parameters of the Thevenin equivalent load model. With the estimated data from the measured voltage and current waveform at the PCC during certain period violating upper control limit, the individual contributions to the distortion of voltage waveform at an interested harmonic frequency have been calculated and shown by simple graph.

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A Study on Isolated DCM Converter for High Efficiency and High Power Factor

  • Kwak, Dong-Kurl
    • Journal of Electrical Engineering and Technology
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    • v.5 no.3
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    • pp.477-483
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    • 2010
  • This paper is studied on a novel buck-boost isolated converter for high efficiency and high power factor. The switching devices in the proposed converter are operated by soft switching technique using a new quasi-resonant circuit, and are driven with discontinuous conduction mode (DCM) according to pulse width modulation (PWM). The quasi-resonant circuit makes use of a step up-down inductor and a loss-less snubber capacitor. The proposed converter with DCM also simplifies the requirement of control circuit and reduces a number of control components. The input ac current waveform in the proposed converter becomes a quasi sinusoidal waveform in proportion to the magnitude of input ac voltage under constant switching frequency. As a result, it is obtained by the proposed converter that the switching power losses are low, the efficiency of the converter is high, and the input power factor is nearly unity. The validity of analytical results is confirmed by some simulation results on computer and experimental results.

A Study On the Automatic Cardiac Output Control Without Pressure Sensors for the motor-driven Totally Implantable TAH Using Motor-Current Waveform Analysis (모터구동형 완전이식 인공심장에서 전류파형의 분석에 의한 심박출량 자동제어 알고리즘의 개발)

  • Choe, Won-U;Kim, Hui-Chan;Min, Byeong-Gu
    • Proceedings of the KOSOMBE Conference
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    • v.1992 no.11
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    • pp.130-135
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    • 1992
  • In this paper a new cardiac output control method without pressure sensors is presented for the rotor-driven totally implantable TAH using motor-current wavelet analysis. Theoretical analysis and mock circulation system experiment results show that cardiac output of TAH, which is indeperdent of afterload and sensitively dependent to preload, is well controlled for the independently variable preload.

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Torque Ripple Reduction Method of SRM Drives Using Neural Network Technique (신경회로망기법을 이용한 SRM 드라이브의 토오크리플 저감방안)

  • Lee, Seong-Du;Jung, Tae-Uk;Ahn, Jin-Woo;Hwang, Young-Moon
    • Proceedings of the KIEE Conference
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    • 1997.07a
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    • pp.227-229
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    • 1997
  • The torque of SRM is developed by phase currents and inductance variation. The inductance of torque generation region is nonlinearly varied according to phase current. By this nonlinear characteristics, torque ripple can be generated on the condition of constant current. Otherwise, phase current should be controlled instantaneously in accordance with inductance to reduce torque ripple. In this paper, the control system with neural network that can reduce torque ripple is suggested. In this control system, instantaneous inductance and optimal current waveform for smallest torque ripple is obtained by neural network. And this required optimal current waveform is regulated by voltage control.

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