An Optimized Transformerless Photovoltaic Grid-Connected Inverter

Xiao, Huafeng; Xie, Shaojun; Cui, Yang; Huang, Ruhai

doi:10.1109/tie.2010.2054056

Cited by 366 publications

(163 citation statements)

References 16 publications

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“…In order to reduce the leakage current, the inverter topology in [21] is used. The dc-link voltage is rectified by a three-phase voltage regulator and manually set to be 400V.…”

Section: B Experimental Resultsmentioning

confidence: 99%

Systematic Current Control Strategy with Pole Assignment for Grid-Connected LCL-Filtered Inverters

Xu¹,

Xie²,

Tang³

2013

Journal of Power Electronics

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For grid-connected LCL-filtered inverters, resonance yields instability and low bandwidth. As a result, careful designs are required. This paper presents a systematic current control structure, where pole assignment consisting of one or more feedbacks is the inner loop, and the outer loop is the direct grid current control. Several other issues are discussed, such as the inner-loop feedback choices, pole-assignment algorithms, robustness and harmonic rejection. Generally, this kind of strategy has three different types according to the inner-loop feedback choices. Among them, a novel pole-assignment algorithm has been proposed, where the inner control maintains four freely-assigned poles which are just two pairs of conjugated poles located at the fundamental and resonance frequencies separately. It has been found that with the different types, the steady-state and dynamic performances are quite different. Finally, simulations and experiments have been provided to verify the control and design of the proposed methods.

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“…In order to reduce the leakage current, the inverter topology in [21] is used. The dc-link voltage is rectified by a three-phase voltage regulator and manually set to be 400V.…”

Section: B Experimental Resultsmentioning

confidence: 99%

Systematic Current Control Strategy with Pole Assignment for Grid-Connected LCL-Filtered Inverters

Xu¹,

Xie²,

Tang³

2013

Journal of Power Electronics

Self Cite

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“…2 shows the common-mode model for single-phase cascaded H4 PV system, where C pva =C pva1 //C pva2 ， C pvb =C pvb1 //C pvb2 . Based on the common-mode model, the leakage current for the cascaded H4 inverter can be calculated as (5). …”

Section: Single-phase Cascaded H4 Invertermentioning

confidence: 99%

Single phase cascaded H5 inverter with leakage current elimination for transformerless photovoltaic system

Guo

Jia

et al. 2016

2016 IEEE Applied Power Electronics Conference and Exposition (APEC)

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Abstract-Leakage current reduction is one of the important issues for the transformelress PV systems. In this paper, the transformerless single-phase cascaded H-bridge PV inverter is investigated. The common mode model for the cascaded H4 inverter is analyzed. And the reason why the conventional cascade H4 inverter fails to reduce the leakage current is clarified. In order to solve the problem, a new cascaded H5 inverter is proposed to solve the leakage current issue. Finally, the experimental results are presented to verify the effectiveness of the proposed topology with the leakage current reduction for the singlephase transformerless PV systems.

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“…However, this method does not clamp CMV to half of the DC-link voltage during zero vector generation [2]. For this purpose, an active switch is inserted between the midpoint of the split DC-link capacitors and the upper terminal of the full-bridge module, which is called the DC-based H6 inverter [11]. If two passive diodes are inserted into the H6 inverter to achieve passive clamping performance, then the DC-based neutral point clamp (NPC) H6 inverter is obtained [9].…”

Section: Introductionmentioning

confidence: 99%

Optimized Hybrid Modulation Strategy for AC Bypass Transformerless Single-Phase Photovoltaic Inverters

Deng¹,

Sun²,

Yang³

et al. 2016

Journal of Power Electronics

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The full-bridge inverter, widely used for single-phase photovoltaic grid-connected applications, presents a leakage current issue. Therefore, an AC bypass branch is introduced to overcome this challenge. Nevertheless, existing modulation strategies entail drawbacks that should be addressed. One is the zero-crossing distortion (ZCD) of the AC current caused by neglecting the AC filter inductor voltage. Another is that the system cannot deliver reactive power because the AC bypass branch switches at the power frequency. To address these problems, this work proposes an optimized hybrid modulation strategy. To reduce ZCD, the phase angle of the inverter output voltage reference is shifted, thereby compensating for the neglected leading angle. To generate the reactive power, the interval of the negative power output is calculated using the power factor. In addition, the freewheeling switch is kept on when power is flowing into the grid and commutates at a high frequency when power is fed back to the DC side. In this manner, the dead-time insertion in the high-frequency switching area is minimized. Finally, the performances of the proposed modulation strategy and traditional strategies are compared on a universal prototype inverter. Experimental results validate the theoretical analysis.

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An Optimized Transformerless Photovoltaic Grid-Connected Inverter

Cited by 366 publications

References 16 publications

Systematic Current Control Strategy with Pole Assignment for Grid-Connected LCL-Filtered Inverters

Systematic Current Control Strategy with Pole Assignment for Grid-Connected LCL-Filtered Inverters

Single phase cascaded H5 inverter with leakage current elimination for transformerless photovoltaic system

Optimized Hybrid Modulation Strategy for AC Bypass Transformerless Single-Phase Photovoltaic Inverters

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