• Title/Summary/Keyword: Average Current Mode

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Effects of Imperfect Sinusoidal Input Currents on the Performance of a Boost PFC Pre-Regulator

  • Cheung, Martin K.H.;Chow, Martin H.L.;Lai, Y.M.;Loo, K.H.
    • Journal of Power Electronics
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    • v.12 no.5
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    • pp.689-698
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    • 2012
  • This paper investigates the effects of applying different input current waveshapes on the performance of a continuous-conduction-mode (CCM) power-factor-correction (PFC) boost pre-regulator. It is found that the output voltage ripple of the pre-regulator can be reduced if the input current is modified to include controlled amount of higher order harmonics. This finding allows us to balance the performance of output regulation and the harmonic current emission when coming to the design of the pre-regulator. An experimental PFC boost pre-regulator prototype is constructed to verify the analysis and show the benefit of the pre-regulator operating with input current containing higher order harmonics.

Current Balance Controller for Parallel Boost Converter with Peak Current Mode Control (첨두전류모드 제어기로 구동되는 병렬 승압컨버터의 전류분배 제어기)

  • Park, Jong-Gyu;Jang, Eun-Sung;Kang, Sin-Chul;Shin, Yong-Hwan;Shin, Hwi-Beom
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.2
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    • pp.301-307
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    • 2009
  • In the paralleled converter module with peak current mode control, current imbalance appears when the voltage controllers with integral control of converter module are not exactly identical. In this paper, the voltage controller is designed to equal the current command of each converter module using the current command bus. The current balance controller is also proposed to balance the average currents of converter modules with imbalaced inductance. It is designed to have good transient response. Proposed method is implemented with the paralleled 2-module and 4-module boost converters with imbalanced inductance. Experimental results verify the performance of current share during both steady and transient states of converter.

An E-capless AC-DC CRM Flyback LED Driver with Variable On-time Control

  • Yao, Kai;Bi, Xiaopeng;Yang, Siwen
    • Journal of Power Electronics
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    • v.17 no.2
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    • pp.315-322
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    • 2017
  • LED is a promising new generation of green lighting with the advantages of high efficiency, good optical performance, long lifetime and environmental friendliness. A pulsating current can be used to drive LEDs. However, current with a high peak-to-average ratio is unfavorable for LEDs. A novel control scheme for the ac-dc critical conduction mode (CRM) flyback LED driver is proposed in this paper. By using the input voltage, output voltage and average output current to control the turn-on time of the switch, the peak-to-average ratio of the output current can be reduced. The operation principle is analyzed and an implementation circuit is put forward. Experimental results show the effectiveness of the proposed scheme.

Input Current Ripple Improvement on Interleaved Boost Power Factor Corrector Operating in Discontinuous Current Mode (불연속 전류모드로 동작하는 Interleaved 승압형 역률보상 컨버터의 입력전류 리플개선)

  • 허태원;박지호;노태균;김동완;박한석;우정인
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.17 no.1
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    • pp.116-123
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    • 2003
  • In this paper, interleaved boost converter is applied as a pre-regulator in switched mode power supply. The pre-regulator plays a role to improve power factor. Interleaved Boost Power Factor Corrector(IBPFC) can reduce input current ripple as a single voltage control loop only without inner current loop, because input current is divided each 50% by two switching devices. Each converter cell is also operated in discontinuous current mode and inductor current of each converter is discontinuous. Total input current which is composed by each converter cell is continuous current. Thus, IBPFC is able to improve input current ripple. IBPFC operating in discontinuous current mode can be classified as six modes from switching state and be carried out state space averaging small signal modeling. A control transfer function is obtained according to the modeling. Single voltage control loop is also constructed by the control transfer function. From experimental result, improvement of power factor and input current ripple are verified.

A Study of Failure Mode for 3 Phase VSI by Power Loss Averaging Technique (전력 손실 평균화 기법에 의한 3상 전압형 인버터의 소손 모드에 관한 연구)

  • Cho, S.E.;Park, S.J.
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.3
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    • pp.575-580
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    • 2010
  • This paper is to design an optimum power conversion device for the system required for development of a low cost 3-phase power inverter. For this purpose, in order to meet with endurance required by the industry, failure mode is standardized to guarantee lifetime of a power semiconductor by monitoring real time power loss and to facilitate failure mode analysis. As normality of heat loss of a power semiconductor is identified remaining in a certain range by comparing heat rise slope between that is calculated by using average current or average loss and that is measured at a heat sink, its feasibility is confirmed by experiment.

Design and Implementation of a Current Controller for Boost Converters Using a DSP (DSP를 이용한 부스트 컨버터의 전류 제어기 설계 및 구현)

  • Lee, Kwang-Woon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.3
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    • pp.259-265
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    • 2012
  • This paper introduces a method for design and implementation of a current controller for boost converter operating in continuous conduction mode (CCM) using a digital signal processor (DSP). A Proportional-Integral (PI) type current controller outputs an average voltage command for inductor, used in the input side of the boost converter, and the duty-ratio of PWM (pulse width modulation) signal for switching device is directly calculated from the average voltage command. The gains of the PI current controller are selected such that the current response characteristics are the same as those of a first-order low-pass filter. The proposed current control scheme is implemented using a DSP based on fixed-point math operations and an experimental study has been performed to validate the proposed method.

Comparative Analysis of Current Controls for Boost PFC Converter under Light Load

  • Juil Kim;Yeong-Jun Choi
    • Journal of the Korea Society of Computer and Information
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    • v.29 no.6
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    • pp.143-151
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    • 2024
  • In this paper, the inductor current distortion in a boost PFC (Power Factor Correction) converter under light load is mathematically analyzed, and its reasons are defined. In the average current mode control under light load, the inductor current is discontinuous, resulting in an inaccurate inductor current average value being reflected in the current control. In predictive current mode control, the current ripple is relatively large compared to the inductor current, leading to severe current distortion. In addition, the switch is turned off near the peak of the inductor current when model predictive current control is applied. Inductor current distortion must be addressed because it leads to an increase in total harmonic distortion and a decrease in power factor. In this paper, the design procedure to mitigate the light load current distortion in boost PFC converter is selected based on the mathematical analysis. Finally, a comparative analysis of control methods under light load is performed using hardware-in-the-loop simulation.

Intra Mode Coding using Candidate Mode Table in HEVC (HEVC에서 후보 모드 표를 이용한 화면내 모드 부호화)

  • Choi, Jung-Ah;Ho, Yo-Sung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.3A
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    • pp.157-162
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    • 2012
  • In this paper, we propose a new intra mode coding method using the candidate mode table. In the conventional HEVC, if the predicted most probable mode (MPM) is not same with the current prediction mode, the current prediction mode is encoded using the fixed length code (FLC). However, since a large number of modes are used in HEVC, the codeword length of FLC gets longer. In this paper, we generate the candidate mode table from neighboring blocks and encode the obtained intra mode index using Golomb-Rice code instead of FLC, when the predicted MPM is not identical to the current mode. From the experiment, we verified that the proposed method reduces the BD-rate by 0.5% on average, compared to the HEVC intra mode coding method.

Time-Delay Effects on DC Characteristics of Peak Current Controlled Power LED Drivers

  • Kim, Marn-Go;Jung, Young-Seok
    • Proceedings of the KIPE Conference
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    • 2011.07a
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    • pp.481-482
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    • 2011
  • New discrete time domain models for the peak current controlled (PCC) power LED drivers in continuous conduction mode include for the first time the effects of time delay in the pulse-width-modulator. Realistic amounts of time delay are found to have significant effects on the average output LED current and on the critical inductor value at the boundary between two conduction modes. Especially, the time delay can provide an accurate LED current for the PCC buck converter with a wide input voltage. The models can also predict the critical inductor values at the mode boundary as functions of the input voltage and the time delay.

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Analysis, Design, and Implementation of a High-Performance Rectifier

  • Wang, Chien-Ming;Tao, Chin-Wang;Lai, Yu-Hao
    • Journal of Power Electronics
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    • v.16 no.3
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    • pp.905-914
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    • 2016
  • A high-performance rectifier is introduced in this study. The proposed rectifier combines the conventional pulse width modulation, soft commutation, and instantaneously average line current control techniques to promote circuit performance. The voltage stresses of the main switches in the rectifier are lower than those in conventional rectifier topologies. Moreover, conduction losses of switches in the rectifier are certainly lower than those in conventional rectifier topologies because the power current flow path when the main switches are turned on includes two main power semiconductors and the power current flow path when the main switches are turned off includes one main power semiconductor. The rectifier also adopts a ZCS-PWM auxiliary circuit to derive the ZCS function for power semiconductors. Thus, the problem of switching losses and EMI can be improved. In the control strategy, the controller uses the average current control mode to achieve fixed-frequency current control with stability and low distortion. A prototype has been implemented in the laboratory to verify circuit theory.