• Title/Summary/Keyword: time-harmonic point load

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A study on the PWM(pulse witdh modulation) current source Inverter with utility (태양광발전 연계 시스템에 의한 PWM 전류형 인버어터에 관한 연구)

  • Hwang, Lak-Hoon;Choi, Ho-Kyu;Sin, Yang-Ho;Lee, Chun-Sang;Kim, Ju-Rae;Jo, Sang-Rou;Jo, Moon-Taeck
    • Proceedings of the KIEE Conference
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    • 2001.07b
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    • pp.1020-1022
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    • 2001
  • because the output of solar cell is direct, it is necessary to install D/A converter system for A.C load, and in case of driving utility line system, it is possible to drive system relation when the system supplies sinusodal current ant voltage having unit power factor. As the characteristics of the soar cell output the is influenced by dailysunight charge, for more electric power it is essential to control the direction toward the san so that the driving point of solar cell can always operate near maximum output point. PWM modulation device among electric power converters must have stable modulation at anytime when it includes noise-factors such as noise-wave and noises on electric voltage wave, a synchronous signal system. In dealing with synchronous signal for control and control signal by microprocessor, it is necessary to compensate it because there is time difference between sample paint and carrier wave. On this papers, single phase PWM current type invertor controled the solar cell having typical voltage dropping character has optimun short current in short, reduces D.C reactance, composes controller for modulation and keeps lower harmonic and high power factor keeping maximum output of solar cell according daily sunlight charge variation.

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Double Boost Power-Decoupling Topology Suitable for Low-Voltage Photovoltaic Residential Applications Using Sliding-Mode Impedance-Shaping Controller

  • Tawfik, Mohamed Atef;Ahmed, Ashraf;Park, Joung-Hu
    • Journal of Power Electronics
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    • v.19 no.4
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    • pp.881-893
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    • 2019
  • This paper proposes a practical sliding-mode controller design for shaping the impedances of cascaded boost-converter power decoupling circuits for reducing the second order harmonic ripple in photovoltaic (PV) current. The cascaded double-boost converter, when used as power decoupling circuit, has some advantages in terms of a high step-up voltage-ratio, a small number of switches and a better efficiency when compared to conventional topologies. From these features, it can be seen that this topology is suitable for residential (PV) rooftop systems. However, a robust controller design capable of rejecting double frequency inverter ripple from passing to the (PV) source is a challenge. The design constraints are related to the principle of the impedance-shaping technique to maximize the output impedance of the input-side boost converter, to block the double frequency PV current ripple component, and to prevent it from passing to the source without degrading the system dynamic responses. The design has a small recovery time in the presence of transients with a low overshoot or undershoot. Moreover, the proposed controller ensures that the ripple component swings freely within a voltage-gap between the (PV) and the DC-link voltages by the small capacitance of the auxiliary DC-link for electrolytic-capacitor elimination. The second boost controls the main DC-link voltage tightly within a satisfactory ripple range. The inverter controller performs maximum power point tracking (MPPT) for the input voltage source using ripple correlation control (RCC). The robustness of the proposed control was verified by varying system parameters under different load conditions. Finally, the proposed controller was verified by simulation and experimental results.