Operation principles and some test results of inverters for grid connected PV systems. Part 1: Operation principles of inverters and MPPT's for grid connected PV systems, and Part 2: Results of an experimental comparative analysis of the Fraunhofer inverter and the TUE-IGBT inverter

摘要

In the first part of this report three main categories of inverters are distinguished: line commutated converters, self-commutated converters without high-frequency transformer (possibly equipped with a low-frequency transformer) and inverters with high-frequency transformer. In the low power range (up to 3 kW) the inverters with high frequency transformer are increasingly popular. The line commutation principle seems to be more suited for higher power application (> 10 kW). In part 1 also four different operation principles for MPPT integrated in inverters are described. In the second part test results and results of a comparative analysis of two remaining types of inverters, i.e. the Fraunhofer inverter and the TUE-IGBT inverter (developed by the Eindhoven University of Technology) are presented. Although the properties of the TUE inverter are quite acceptable, the inverter does not seem to have advantages in comparison to other types of inverters without high-frequency transformer.