• Title/Summary/Keyword: DC-link Capacitor

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Analysis of Joule-heat Characteristics according to the DC-link Capacitor Film Geometrics (DC-link Capacitor필름 형상에 따른 Joule-heat특성 분석)

  • Jeon, Yong Won;Kim, Young Shin;Jeon, Euy Sik
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.1
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    • pp.42-48
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    • 2020
  • As global warming accelerates, eco-friendly electric cars are being developed to reduce carbon dioxide emissions, and power conversion inverters are used to drive motors. Among inverter components, DC-link capacitor is heated by high current usage, which causes problems such as performance and life-saving of inverter. Although metal cases with good thermal performance have been used to solve this problem, it is difficult to apply them in practice due to insulation problems with other parts. In this paper, the Heat-Generation influence factor of DC-link capacitor is analyzed. Variables on heat-generation are set at 3 levels for film width, inductance, and film thickness. Box-Behnken to 13 tests using the design and minimal deviations, e.g. through the experiment three times by each level. The surface of the film k type by attaching the sensor current is measured temperature. Capacitance was set to a minimum level of 200 ㎌ and had a frequency of 16 kHz with Worst case, ambient temperature of 85℃ and a ripple current of 50 Ams was applied. The temperature at the measurement point was collected in the data logger after sampling at 1 minute intervals for 2 hours after saturation with the ambient temperature. This experiment confirmed that setup factors are correlated with heat-generation.

Improved dc-link capacitor voltage control of Distribution Static Compensator (배전용 정지형 보상기의 개선된 직류단 커패시터 전압제어)

  • Kim, Ho-Yeol;Choi, Jong-Woo
    • Proceedings of the KIPE Conference
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    • pp.466-467
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    • 2010
  • Researches about DSTATCOM are mainly divided two parts, one is the calculation of the load-side average active power and dc-link capacitor average voltage, the other part is the current control. This paper proposes a calculation of dc-link capacitor average voltage using improved method instead of conventional method using LPF (low pass filter). Through the theoretical analysis and simulation under unbalance loads and non-linear load, the proposed method is verified.

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Finite State Model-based Predictive Current Control with Two-step Horizon for Four-leg NPC Converters

  • Yaramasu, Venkata;Rivera, Marco;Narimani, Mehdi;Wu, Bin;Rodriguez, Jose
    • Journal of Power Electronics
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    • v.14 no.6
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    • pp.1178-1188
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    • 2014
  • This study proposes a finite-state model predictive controller to regulate the load current and balance the DC-link capacitor voltages of a four-leg neutral-point-clamped converter. The discrete-time model of the converter, DC-link, inductive filter, and load is used to predict the future behavior of the load currents and the DC-link capacitor voltages for all possible switching states. The switching state that minimizes the cost function is selected and directly applied to the converter. The cost function is defined to minimize the error between the predicted load currents and their references, as well as to balance the DC-link capacitor voltages. Moreover, the current regulation performance is improved by using a two-step prediction horizon. The feasibility of the proposed predictive control scheme for different references and loads is verified through real-time implementation on the basis of dSPACEDS1103.

Control of Motor Drives Fed by PFC Circuits without DC-Link Electrolytic Capacitors

  • Kim, Kwang-Man;Kim, Eung-Ho;Choi, Jong-Woo
    • Journal of Power Electronics
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    • v.18 no.4
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    • pp.1067-1074
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    • 2018
  • This paper presents a control method for variable-speed motor drives that do not use a DC-link electrolytic capacitor. The proposed circuit consists of a power factor correction converter for boosting the DC-link voltage, an inverter for driving the motor, and a small DC-link film capacitor. By employing a small DC-link capacitor, the proposed circuit that is small, and a low cost and weight are achieved. However, because the DC-link voltage varies periodically, the control of the circuit is more difficult than that of the conventional method. Using the proposed control method, an inverter can be controlled reliably even when the capacitance of the DC-link capacitor is very small. Experiments are performed using a 1.5-kW inverter with a $20-{\mu}F$ DC-link capacitor, and the experimental results are analyzed thoroughly.

DC-Link Voltage Control of Distribution Static Compensator using Ripple Voltage Extraction (맥동 전압 추출을 통한 배전용 정지형 보상기의 직류링크 전압제어)

  • Kim, Ho-Yeol;Choi, Jong-Woo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.1
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    • pp.8-13
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    • 2012
  • DSTATCOM is active filter that reduces nonlinear and unbalanced currents. Researches about DSTATCOM are mainly divided two parts, one is the reference value calculation of compensation current depending on the calculation of the load-side average active power and dc-link capacitor average voltage, the other part is actual current control depending on the reference value of compensation current. This paper proposes a calculation of dc-link capacitor average voltage ripple voltage extraction instead of conventional method using LPF. The utility of the proposed algorithm is verified through the theoretical analysis and the experiment under unbalance loads and non-linear load.

Control Strategies of Doubly Fed Induction Generator -Based Wind Turbines with Crowbar Activation (Crowbar 운전을 가지는 이중여자유도발전기 풍력발전시스템의 제어전략)

  • Justo, Jackson John;Ro, Kyoung-Soo
    • Proceedings of the KIEE Conference
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    • pp.706-707
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    • 2011
  • The insertion of the crowbar system in the doubly fed induction generator rotor circuit for a short period of time during grid disturbance enables a more efficient way of limiting transient rotor current and hence protecting the rotor side converter (RSC) and the DC - link capacitor. When crowbar is activated at fault occurrence and clearance time, RSC is blocked while DC -link capacitor and the grid side converter (GSC) can be controlled to provide reactive power support at the PCC and improve the voltage which helps to comply with grid codes. In this paper, control strategies for crowbar system to limit the rotor current during fault is presented with RSC and GSC controllers are modified to control PCC voltage during disturbance to enhance DFIG wind farm to comply with some strict grid codes. Model simulated on MATLAB/Simulink verify the study through simulation results presented.

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A study on neutral-point voltage balance with harmonic component injection for single phase three-level NPC converter (고조파 주입을 통한 단상 3레벨 NPC 컨버터 중성점 전압 밸런싱 연구)

  • Kang, Kyoung Pil;Kim, Ho-Sung;Cho, Jintae;Cho, Younghoon
    • Proceedings of the KIPE Conference
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    • pp.316-317
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    • 2018
  • This paper propse the DC link capacitor voltage balancing control for three level neutral point clamped converter with harmonic component injection method. The injcetion voltage consists of harmonic component and DC link capacitor voltage difference. Theoretical analysis is provided to balance the DC link voltage, and it shows that harmonic component compensates the unbalanced condition between the capacitors. Both simulations and experiments are carried out to show that the voltage unbalance have been decreased by the proposed method.

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Capacitance Estimation of DC-Link Capacitor Considering Temperature Effect

  • Pu, Xingsi;Kim, Kyung-Hyun;Lee, Dong-Choon;Lee, Kyo-Beom;Kim, Jang-Mok
    • Proceedings of the KIPE Conference
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    • pp.156-157
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    • 2010
  • This paper proposes a correction method of capacitance estimation considering the temperature effect for the DC-link capacitor banks in three-phase AC/DC PWM converters. In this work, a sensing circuit using a temperature sensor is designed for measuring the operating temperature. Capacitance value is corrected considering the measured temperature. This method has been implemented in experiment.

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Type-2 Fuzzy Logic Predictive Control of a Grid Connected Wind Power Systems with Integrated Active Power Filter Capabilities

  • Hamouda, Noureddine;Benalla, Hocine;Hemsas, Kameleddine;Babes, Badreddine;Petzoldt, Jurgen;Ellinger, Thomas;Hamouda, Cherif
    • Journal of Power Electronics
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    • v.17 no.6
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    • pp.1587-1599
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    • 2017
  • This paper proposes a real-time implementation of an optimal operation of a double stage grid connected wind power system incorporating an active power filter (APF). The system is used to supply the nonlinear loads with harmonics and reactive power compensation. On the generator side, a new adaptive neuro fuzzy inference system (ANFIS) based maximum power point tracking (MPPT) control is proposed to track the maximum wind power point regardless of wind speed fluctuations. Whereas on the grid side, a modified predictive current control (PCC) algorithm is used to control the APF, and allow to ensure both compensating harmonic currents and injecting the generated power into the grid. Also a type 2 fuzzy logic controller is used to control the DC-link capacitor in order to improve the dynamic response of the APF, and to ensure a well-smoothed DC-Link capacitor voltage. The gained benefits from these proposed control algorithms are the main contribution in this work. The proposed control scheme is implemented on a small-scale wind energy conversion system (WECS) controlled by a dSPACE 1104 card. Experimental results show that the proposed T2FLC maintains the DC-Link capacitor voltage within the limit for injecting the power into the grid. In addition, the PCC of the APF guarantees a flexible settlement of real power exchanges from the WECS to the grid with a high power factor operation.

Practical Design and Implementation of a Power Factor Correction Valley-Fill Flyback Converter with Reduced DC Link Capacitor Volume (저감된 DC Link Capacitor 부피를 가지는 역률 개선 Valley-Fill Flyback 컨버터의 설계 및 구현)

  • Kim, Se-Min;Kang, Kyung-Soo;Kong, Sung-Jae;Yoo, Hye-Mi;Roh, Chung-Wook
    • The Transactions of the Korean Institute of Power Electronics
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    • v.22 no.4
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    • pp.277-284
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    • 2017
  • For passive power factor correction, the valley fill circuit approach is attractive for low power applications because of low cost, high efficiency, and simple circuit design. However, to vouch for the product quality, two dc-link capacitors in the valley fill circuit should be selected to withstand the peak rectified ac input voltage. The common mode (CM) and differential mode (DM) choke should be used to suppress the electromagnetic interference (EMI) noise, thereby resulting in large size volume product. This paper presents the practical design and implementation of a valley fill flyback converter with reduced dc link capacitors and EMI magnetic volumes. By using the proposed over voltage protection circuit, dc-link capacitors in the valley fill circuit can be selected to withstand half the peak rectified ac input voltage, and the proposed CM/DM choke can be successfully adopted. The proposed circuit effectiveness is shown by simulation and experimentally verified by a 78W prototype.