Leakage Current Reduction in Single-Phase Grid-Connected Inverters—A Review
Open Access
- 31 March 2020
- journal article
- review article
- Published by MDPI AG in Applied Sciences
- Vol. 10 (7), 2384
- https://doi.org/10.3390/app10072384
Abstract
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.This publication has 86 references indexed in Scilit:
- Photovoltaic penetration issues and impacts in distribution network – A reviewRenewable and Sustainable Energy Reviews, 2016
- Highly Reliable Transformerless Photovoltaic Inverters With Leakage Current and Pulsating Power EliminationIEEE Transactions on Industrial Electronics, 2015
- A New Common-Mode Transformerless Photovoltaic InverterIEEE Transactions on Industrial Electronics, 2015
- Transformerless Photovoltaic Inverter Based on Interleaving High-Frequency Legs Having Bidirectional CapabilityIEEE Transactions on Power Electronics, 2015
- Topology Review and Derivation Methodology of Single-Phase Transformerless Photovoltaic Inverters for Leakage Current SuppressionIEEE Transactions on Industrial Electronics, 2015
- Single phase transformerless inverter topologies for grid-tied photovoltaic system: A reviewRenewable and Sustainable Energy Reviews, 2015
- Study on Laser Welding of Case Closure Weld for ITER Correction CoilIEEE Transactions on Applied Superconductivity, 2013
- A Review of Single-Phase Grid-Connected Inverters for Photovoltaic ModulesIEEE Transactions on Industry Applications, 2005
- Novel single-stage half-bridge series-resonant buck-boost inverterIEEE Transactions on Aerospace and Electronic Systems, 2004
- Novel topology for parallel connection of soft-switching high-power high-frequency invertersIEEE Transactions on Industry Applications, 2003