EMC of PV-plants with line-commutated inverters

Abstract

The new European EMC (electromagnetic compatibility) standard (EN 61000-3-2) became valid from the beginning of 1996, and although a revision may already be considered, producers of PV-inverters will have to face a growing interest in their equipment's EMC-properties. In the case of line-commutated inverters EMC-problems are mainly related with current harmonics and power factor. In this paper it is shown by simulation and measurements that a usual 6-pulse inverter will cope with the above standards in the whole range of operation up to 11 kW, if an adequate passive LC-filter is introduced into the grid connection. Since this filter almost does not affect the inverter's efficiency, it is considered to be a very effective and economic solution to line bound EMC-problems. The results are presented in the form of diagrams for easy reference to the designer. The radio interference can be avoided using the standard thyristor RC-damping against fast voltage gradients.