An Improved H5 Topology With Low Common-Mode Current for Transformerless PV Grid-Connected Inverter

Lei, Hong; Zeng, Yangbin; Zhang, Bo; Zheng, Trillion Q.; Hao, Ruixiang; Yang, Zezhong

doi:10.1109/tpel.2018.2833144

Cited by 101 publications

(35 citation statements)

References 37 publications

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“…Some CSI topologies have been shown in recent research [72][73][74]. Nowadays, CSI topologies try to reduce the leakage current, such as H5 [75], H6 [76] and HERIC [77].…”

Section: H5 H6 and Heric Invertersmentioning

confidence: 99%

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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“…Some CSI topologies have been shown in recent research [72][73][74]. Nowadays, CSI topologies try to reduce the leakage current, such as H5 [75], H6 [76] and HERIC [77].…”

Section: H5 H6 and Heric Invertersmentioning

confidence: 99%

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

et al. 2020

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“…As the other approach for the transformer-less inverters that have been presented in the references herein 39,[45][46][47] and shown in Figure 2D-G, both of the inductors L A and L B are available and usually equal. According to Equations 3 and 4, for this state, V dm = 0.…”

Section: Generation and Elimination Of I C Mmentioning

confidence: 99%

An FPGA‐based switching photovoltaic‐connected inverter topology for leakage current suppression in grid‐connected utilizations

Ghaderi

2020

Circuit Theory & Apps

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This study presents a symmetrical photovoltaic (PV)-connected inverter topology for eliminating the common-state leakage current in grid-connected inverters. A new inverter topology is introduced that minimizes the leakage current, increases efficiency, and is economically viable because it consists of six power switches and two power diodes that, compared with similar ones, consist of the same element numbers. In this inverter, power losses are lower than popular topologies such as H5, H6, and HERIC, and the voltage stresses of the switches are reduced. These features are due to the unique composition of the inverter branches and the location of the switches and diodes and the formation of a suitable freewheeling path for the current. The freewheeling path separates the alternating current (AC) side from the direct current side in the converter and cuts off the PV array leakage current to the AC grid. This will improve network reliability indices and maintain conservation standards. Finally, the content of this method is validated by comparing the proposed inverter with the existing conventional topologies. A prototype has been implemented for the performance analysis of the proposed inverter and results presented.

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“…A transformer less PV inverter with cascaded H-bridge for leakage current reduction in solar array is presented in [32]. The conventional three-phase cascaded H4 grid inverter is evaluated using the common mode current model.…”

Section: Fig7 Modified Z-source Inverter Topologymentioning

confidence: 99%

Technological Developments in Direct Grid Connected Power Converters for Solar PV Power Plants

Kumar¹,

Ganesh²

2019

IJEAT

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Most of the countries in the world are concentrating on renewable energy generation, due to day-day increase in population increasing the energy demand, also to make their environment sustainable. With the many of features, use of megawatts rating solar photovoltaic (PV) power plants are becoming more popular for upgrading the existing power generation throughout the world. Moreover, among the existing renewable energy generations, solar power is the primary choice to meet the rapidly increasing demands; since solar PV plant installing time is relatively quick, say about in 3- 4 months, compared to conventional (thermal, hydro & diesel) plants which may require about 3-4 years. The low voltage (270‒700V) power converters require a filter and a step-up transformer for interconnecting the local grids with solar PV power plants. The advances in power converters without transformers and filters have recently become more attractive for solar PV power plants connected directly to grid. The study of this article describes the essential requirement and the technological developments in the design of power electronics converters, together with their modulation schemes to integrate solar power directly with standard power grid. This article, review ongoing research activities and the probable directions for the future research in developing inverters for cost-efficient grid connected solar PV plants

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An Improved H5 Topology With Low Common-Mode Current for Transformerless PV Grid-Connected Inverter

Cited by 101 publications

References 37 publications

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

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

An FPGA‐based switching photovoltaic‐connected inverter topology for leakage current suppression in grid‐connected utilizations

Technological Developments in Direct Grid Connected Power Converters for Solar PV Power Plants

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