A Topology Synthetization Method for Single-Phase, Full-Bridge, Transformerless Inverter with Leakage Current Suppression—Part II

Yue, Xiumei; Wang, Hongliang; Zhu, Xiaonan; Wei, Xinwei; Liu, Yanfei

doi:10.3390/en13020446

Cited by 4 publications

(2 citation statements)

References 46 publications

(23 reference statements)

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“…The main problems are-an increase in losses, current harmonics, safety issues, and interference problems of electromagnetic effect [23]. These problems have been reported in different papers [24][25][26][27].…”

Section: Dc/ac Convertermentioning

confidence: 97%

Leakage Current Reduction in Single-Phase Grid-Connected Inverters—A Review

et al. 2020

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The rise in renewable energy has increased the use of DC/AC converters, which transform the direct current to alternating current. These devices, generally called inverters, are mainly used as an interface between clean energy and the grid. It is estimated that 21% of the global electricity generation capacity from renewable sources is supplied by photovoltaic systems. In these systems, a transformer to ensure grid isolation is used. Nevertheless, the transformer makes the system expensive, heavy, bulky and reduces its efficiency. Therefore, transformerless schemes are used to eliminate the mentioned disadvantages. One of the main drawbacks of transformerless topologies is the presence of a leakage current between the physical earth of the grid and the parasitic capacitances of the photovoltaic module terminals. The leakage current depends on the value of the parasitic capacitances of the panel and the common-mode voltage. At the same time, the common-mode voltage depends on the modulation strategy used. Therefore, by the manipulation of the modulation technique, is accomplished a decrease in the leakage current. However, the connection standards for photovoltaic inverters establish a maximum total harmonic distortion of 5%. In this paper an analysis of the common-mode voltage and its influence on the value of the leakage current is described. The main topologies and strategies used to reduce the leakage current in transformerless schemes are summarized, highlighting advantages and disadvantages and establishing points of comparison with similar topologies. A comparative table with the most important aspects of each converter is shown based on number of components, modes of operation, type of modulation strategy used, and the leakage current value obtained. It is important to mention that analyzed topologies present a variation of the leakage current between 0 to 180 mA. Finally, the trends, problems, and researches on transformerless grid-connected PV systems are discussed.

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Section: Dc/ac Convertermentioning

confidence: 97%

Leakage Current Reduction in Single-Phase Grid-Connected Inverters—A Review

et al. 2020

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“…Non-isolated inverters do not have these problems [14][15][16]. However, due to the lack of electrical isolation, the CMV of the non-isolated inverters acts on loop impedance to cause leakage current [17][18][19][20][21][22]. The large leakage current can damage the equipment and personal safety [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Comparative analysis of leakage current suppression capability of forward‐clamped and reverse‐clamped H10 three‐phase inverters

Shao

Lan

2021

IET Power Electronics

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Non‐isolated inverters have the disadvantage of large leakage current, which will damage the equipment and personal safety. In order to solve this problem, this paper proposes two H10 three‐phase inverter topologies named forward‐clamped and reverse‐clamped H10 inverters. Each of the topologies is composed of two DC bus switches, a clamping circuit and a traditional three‐phase inverter, but the clamping method of these two topologies is different. A general control strategy combining carrier modulation and logic operation for these two topologies are proposed. The control strategy allows the common‐mode voltage of these two topologies to vary between one third and two thirds of the DC bus voltage, but the frequency of the common‐mode voltage of the reverse‐clamped inverter is three times that of the forward‐clamped inverter. The loop impedance of the reverse‐clamped inverter increases significantly at high frequency, so the leakage current suppression capability is better. Simulation and experiment platforms of the inverter systems are built. The obtained results verify the correctness of the theoretical analysis.

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