Assessment of topologies to minimize leakage currents in transformerless PV inverters

Nowadays, the world is facing two challenges: the need for cleaner environment and the incessant increase in power demands. A situation that makes renewable energy sources, and particularly solar photovoltaics, more and more viable. Solar photovoltaic systems can be connected to the grid either with transformers or without transformers. In fact, the transformerless systems have been investigated and found to offer higher efficiency, smaller size and weight as well as more reduced cost. However, when no transformer is used, a common-mode voltage would appear and lead to leakage currents between the PV-array and the ground. This is why the main focus of recent researches is on minimizing or totally avoiding these leakage currents without causing any impact on the whole system efficiency. Accordingly, this paper deals with a comparison of promising solutions to achieve such a crucial goal.

[1]  Fei Zhou,et al.  Leakage current analysis of a single-phase transformer-less PV inverter connected to the grid , 2008, 2008 IEEE International Conference on Sustainable Energy Technologies.

[2]  U. Borup,et al.  Transformerless Photovoltaic Inverters Connected to the Grid , 2007, APEC 07 - Twenty-Second Annual IEEE Applied Power Electronics Conference and Exposition.

[3]  Roberto González,et al.  Transformerless Single-Phase Multilevel-Based Photovoltaic Inverter , 2008, IEEE Transactions on Industrial Electronics.

[4]  Fritz Schimpf,et al.  Grid connected Converters for Photovoltaic, State of the Art, Ideas for Improvement of Transformerless Inverters , 2008 .

[5]  Pablo Sanchis,et al.  High-Efficiency Transformerless Single-phase Photovoltaic Inverter , 2006, 2006 12th International Power Electronics and Motion Control Conference.

[6]  F. Blaabjerg,et al.  A review of single-phase grid-connected inverters for photovoltaic modules , 2005, IEEE Transactions on Industry Applications.

[7]  Remus Teodorescu,et al.  A New High-Efficiency Single-Phase Transformerless PV Inverter Topology , 2011, IEEE Transactions on Industrial Electronics.

[8]  Marco Liserre,et al.  The high efficiency transformer-less PV inverter topologies derived from NPC topology , 2009, 2009 13th European Conference on Power Electronics and Applications.

[9]  R. L. LaRocca Personnel protection devices for use on appliances , 1992 .

[10]  Hirofumi Akagi,et al.  A New Neutral-Point-Clamped PWM Inverter , 1981, IEEE Transactions on Industry Applications.

[11]  W. Bower,et al.  Investigation of ground-fault protection devices for photovoltaic power system applications , 2000, Conference Record of the Twenty-Eighth IEEE Photovoltaic Specialists Conference - 2000 (Cat. No.00CH37036).

[12]  A. Ahfock,et al.  Comparison between unipolar and bipolar single phase gridconnected inverters for PV applications , 2007, 2007 Australasian Universities Power Engineering Conference.