• Title/Summary/Keyword: Single-stage inverter

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Design of Three-port Flyback Inverter for Active Power Decoupling (능동 전력 디커플링을 위한 3권선 방식의 플라이백 인버터 설계)

  • Kim, Kyu-Dong;Kim, Jun-Gu;Lee, Tae-Won;Jung, Yong-Chae;Won, Chung-Yuen
    • Proceedings of the KIPE Conference
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    • 2012.07a
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    • pp.486-487
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    • 2012
  • In this paper, novel three-port active power decoupling (APD) method for applying 250[W] micro-inverter. This type using third port for active power decoupling stores the surplus energy and supplies sufficient energy to grid. Conventional decoupling circuit is applied in single phase grid connected micro-inverter especially single-stage configuration like flyback-type DC-AC inverter. In this passive power decoupling method, electrolytic capacitor with large capacitance is needed for decoupling from constant DC power and instantaneous AC power. However the decoupling capacitor is replaced with film capacitor by using APD, thus the overall system can achieve smaller size and long lifespan. Proposed three-port flyback inverter is verified by design and simulation.

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A Three Phase Three-level PWM Switched Voltage Source Inverter with Zero Neutral Point Potential

  • Oh Won-Sik;Han Sang-Kyoo;Choi Seong-Wook;Moon Gun-Woo
    • Journal of Power Electronics
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    • v.5 no.3
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    • pp.224-232
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    • 2005
  • A new three phase three-level Pulse Width Modulation (PWM) Switched Voltage Source (SVS) inverter with zero neutral point potential is proposed. It consists of three single-phase inverter modules. Each module is composed of a switched voltage source and inverter switches. The major advantage is that the peak value of the phase output voltage is twice as high as that of a conventional neutral-point-clamped (NPC) PWM inverter. Thus, the proposed inverter is suitable for applications with low voltage sources such as batteries, fuel cells, or solar cells. Furthermore, three-level waveforms of the proposed inverter can be achieved without the switch voltage imbalance problem. Since the average neutral point potential of the proposed inverter is zero, a common ground between the input stage and the output stage is possible. Therefore, it can be applied to a transformer-less Power Conditioning System (PCS). The proposed inverter is verified by a PSpice simulation and experimental results based on a laboratory prototype.

A Second-order Harmonic Current Reduction with a Fast Dynamic Response for a Two-stage Single-phase Grid-connected Inverter

  • Jung, Hong-Ju;Kim, Rae-Young
    • Journal of Electrical Engineering and Technology
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    • v.9 no.6
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    • pp.1988-1994
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    • 2014
  • In a single-phase grid-connected power system consisting of a DC/DC converter and a DC/AC converter, the current drawn from renewable energy sources has a tendency to be pulsated and contains second-order frequency ripple components, which results in several drawback such as a power harvesting loss and a shortening of the energy source's life. This paper presents a new second-order harmonic current reduction scheme with a fast dc-link voltage loop for two-stage dc-dc-ac grid connected systems. In the frequency domain, an adequate control design is performed based on the small signal transfer function of a two-stage dc-dc-ac converter. To verify the effectiveness of proposed control algorithm, a 1 kW hardware prototype has been built and experimental results are presented.

Characteristic Estimation of Single-Stage High Frequency Resonant Inverter Link Type DC-DC Converter (단일 전력단 고주파 공진 인버터 링크형 DC-DC 컨버터의 특성평가)

  • Won, Jae-Sun;Kim, Hae-Jun;Park, Jae-Wook;Nam, Seung-Sik;Seo, Cheol-Sik;Kim, Dong-Hee
    • Proceedings of the KIEE Conference
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    • 2003.07b
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    • pp.1190-1192
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    • 2003
  • This paper presents a novel single-stage high frequency resonant inverter link type DC-DC converter using zero voltage switching with high input power factor. The proposed high frequency resonant converter integrates half-bridge boost rectifier as power factor corrector (PFC) and half-bridge resonant converter into a single stage. The input stage of the half-bridge boost rectifier is working in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that boost converter make the line current follow naturally the sinusoidal line voltage waveform. Experimental results have demonstrated the feasibility of the proposed DC-DC converter. This proposed converter will be able to be practically used as a power supply in various fields as induction heating applications, DC-DC converter etc.

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New MPPT Control Strategy for Two-Stage Grid-Connected Photovoltaic Power Conditioning System

  • Bae, Hyun-Su;Park, Joung-Hu;Cho, Bo-Hyung;Yu, Gwon-Jong
    • Journal of Power Electronics
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    • v.7 no.2
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    • pp.174-180
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    • 2007
  • In this paper, a simple control method for two-stage utility grid-connected photovoltaic power conditioning systems (PCS) is proposed. This approach enables maximum power point (MPP) tracking control with post-stage inverter current information instead of calculating solar array power, which significantly simplifies the controller and the sensor. Furthermore, there is no feedback loop in the pre-stage converter to control the solar array voltage or current because the MPP tracker drives the converter switch duty cycle. This simple PCS control strategy can reduce the cost and size, and can be utilized with a low cost digital processor. For verification of the proposed control strategy, a 2.5kW two-stage photovoltaic grid-connected PCS hardware which consists of a boost converter cascaded with a single-phase inverter was built and tested.

Low-Cost High-Efficiency Two-Stage Cascaded Converter of Step-Down Buck and Tapped-Inductor Boost for Photovoltaic Micro-Inverters (태양광 마이크로 인버터를 위한 탭인덕터 부스트 및 강압형 컨버터 캐스케이드 타입 저가형 고효율 전력변환기)

  • Jang, Jong-Ho;Shin, Jong-Hyun;Park, Joung-Hu
    • The Transactions of the Korean Institute of Power Electronics
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    • v.19 no.2
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    • pp.157-163
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    • 2014
  • This paper proposes a two-stage step-down buck and a tapped-inductor boost cascaded converter for high efficiency photovoltaic micro-inverter applications. The proposed inverter is a new structure to inject a rectified sinusoidal current into a low-frequency switching inverter for single-phase grid with unity power factor. To build a rectified-waveform of the output current. the converter employs both of a high efficiency step-up and a step-down converter in cascade. In step-down mode, tapped inductor(TI) boost converter stops and the buck converter operates alone. In boost mode, the TI converter operates with the halt of buck operation. The converter provides a rectified current to low frequency inverter, then the inverter converts the current into a unity power-factor sinusoidal waveform. By applying a TI, the converter can decrease the turn-on ratios of the main switch in TI boost converter even with an extreme step-up operation. The performance validation of the proposed design is confirmed by an experimental results of a 120W hardware prototype.

Controller Design and By-Pass Structure for the Two-Stage Grid-Connected Photovoltaic Power Conditioning System

  • Lee, Seong-Jun;Bae, Hyun-Su;Cho, B.H.
    • Proceedings of the KIPE Conference
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    • 2009.11a
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    • pp.206-208
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    • 2009
  • In this paper, a systematical controller design method for a twostage grid-connected photovoltaic power conditioning system is proposed. For a pre-stage boost converter to achieve the stable operation in the entire region of solar array, the digital resistive current mode controller is used. This algorithm is very simple to implement with a digital controller and there is no power stage parameter dependency in the controller design. For a post-stage single-phase full-bridge inverter, a PI controller with a feedforward compensation for the inner current control is employed. Furthermore, in case that the operating point of the solar array under varying environmental conditions is higher than the required voltage for the inverter current control, the bypass mode for the boost converter is possible for the more efficient operation. The proposed control scheme is validated through the experiment of the prototype two-stage power conditioning system hardware with a 200W solar array.

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A High-efficiency Single-phase Photovoltaic Inverter for High-voltage Photovoltaic Panels (고전압 태양광 패널용 고효율 단상 태양광 인버터)

  • Hyung-Min, Ryu
    • Journal of IKEEE
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    • v.26 no.4
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    • pp.584-589
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    • 2022
  • For DC-AC power conversion from a high-voltage photovoltaic panel to a single-phase grid, the two-stage transformerless inverter with a buck-boost converter followed by a full-bridge inverter is widely used. To avoid an excessive leakage current due to the large parasitic capacitance of the photovoltaic panel, the full-bridge inverter can only adopt the bipolar PWM which results in much higher power loss compared to the unipolar PWM. In order to overcome such a poor efficiency, this paper proposes a new topology in which an IGBT and a diode for circuit isolation are added to the buck-boost converter. The proposed circuit isolation method allows the unipolar PWM in the full-bridge inverter without any increase in the leakage current so that the overall efficiency can be improved. The validity of the proposed solution is verified by computer simulation and power loss calculation.

A High-efficiency Buck-boost Half-bridge Inverter for Single-phase Photovoltaic Generation (단상 태양광 발전용 고효율 벅부스트 하프브리지 인버터)

  • Hyung-Min Ryu
    • Journal of IKEEE
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    • v.27 no.4
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    • pp.450-455
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    • 2023
  • Among single-phase photovoltaic inverters that can avoid excessive leakage current caused by the large parasitic capacitance of photovoltaic panels, a boost converter followed by a half-bridge inverter is the simplest and has the smallest leakage current. However, due to the high DC-link voltage, the rated voltage of the switching devices is high and the switching loss is large. This paper proposes a new circuit topology which can operate as a buck-boost inverter by adding two bidirectional switches to the output side of the half-bridge inverter instead of removing the boost converter. By reducing two stages of power conversion through the high-voltage DC-link to one stage, power loss can be reduced without increasing costs and leakage current. The feasibility of the proposed circuit topology is verified by computer simulation and power loss calculation.

Single Phase Inverter High Frequency Circuit Modeling and Verification for Differential Mode Noise Analysis (차동 노이즈 분석을 위한 단상 인버터 고주파 회로 모델링 및 검증)

  • Shin, Ju-Hyun;Seng, Chhaya;Kim, Woo-Jung;Cha, Hanju
    • The Transactions of the Korean Institute of Power Electronics
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    • v.26 no.3
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    • pp.176-182
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    • 2021
  • This research proposes a high-frequency circuit that can accurately predict the differential mode noise of single-phase inverters at the circuit design stage. Proposed single-phase inverter high frequency circuit in the work is a form in which harmonic impedance components are added to the basic single-phase inverter circuit configuration. For accurate noise prediction, parasitic components present in each part of the differential noise path were extracted. Impedance was extracted using a network analyzer and Q3D in the measurement range of 150 kHz to 30 MHz. A high-frequency circuit model was completed by applying the measured values. Simulations and experiments were conducted to confirm the validity of the high-frequency circuit. As a result, we were able to predict the resonance point of the differential mode voltage extracted as an experimental value with a high-frequency circuit model within an approximately 10% error. Through this outcome, we could verify that differential mode noise can be accurately predicted using the proposed model of the high-frequency circuit without a separate test bench for noise measurement.