ABSTRACT
Conventional PV stand alone power supply systems (SAPSS) mostly operate at low voltage and use directly coupled battery cells as energy storage. Disadvantages of these systems are, for example, serious restrictions in extension of the storage matching growing demand and short battery life resulting from imperfect management of individual battery cells. As a consequence, exploitation costs and reliability of electricity supply do not meet users expectations. An innovative system concept, using AC components only overcomes these problems. In the past AC PV modules already have been developed. However, AC batteries meeting the requirements are not yet available. In the framework of a European research project, development of AC batteries has been tackled. First tests with a number of experimental units have been carried out. The experience gained allows identification of the most promising topology (flexible AC / DC clustering). This knowledge and experience is a sound basis required for prototyping and testing of systems and, finally, industrial product development.
