Design of Photovoltaic Microinverter for Off-Grid and Grid-Parallel Applications

Conference: CIPS 2014 - 8th International Conference on Integrated Power Electronics Systems
02/25/2014 - 02/27/2014 at Nuremberg, Germany

Proceedings: ETG-Fb. 141: CIPS 2014

Pages: 6Language: englishTyp: PDF

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Felgemacher, Christian; Jaeger, Philipp; Kobeissi, Ali; Pfeiffer, Jonas; Wiegand, Dennis; Kruschel, Wolfram; Dombert, Benjamin; Vasconcelos Araújo, Samuel; Zacharias, Peter (University of Kassel, Centre of Competence for Distributed, Electric Power Technology (KDEE), 34121 Kassel, Germany)

The design and construction of a 500VA microinverter for photovoltaic applications is presented. The developed microinverter is capable of operating as a standalone AC voltage source for small loads or, alternatively, as a grid-parallel system. Possible applications are therefore small off-grid installations as well as installations where space constraints do not allow enough modules to be combined to use string inverters. The design of the microinverter is based on a two stage concept. Two alternative topologies for the DC-DC converter stage have been considered. A prototype using a current-fed push-pull converter and a full-bridge output stage has been built and was shown to be operational. The prototype has achieved a maximum overall efficiency of 93.9 %, which includes all sensing, control and driving losses. SiC MOSFETs have been utilized to illustrate the capability of wide-band-gap devices.