Sensorless Control of a Grid-Connected PV Converter

The base of our new developed grid-connected PV converter is a low cost general purpose frequency converter. In spite of the lack of voltage sensors a very reliable anti-island protection is reached. In the first section a control structures of the grid-connected converter with UVOC (Utility Voltage Oriented Control) is given while in the second section a method for the sensorless identification of the grid voltage is suggested. The third section describes an ultimate method for anti-island protection with a negligible none-detection zone. Finally the experimental results of the developed low cost general purpose frequency converter are presented.