| Abstract |
Due to the increasing number of inverters in renewable supply systems and a lot of UPS-applications
the control of single phase systems is becoming more important. Hence a new control strategy for
single phase inverters has been derived which allows both precise control and fast signal
conditioning. The vector control with PI-controllers, which is well known from three phase systems,
allows the precise and fast control of inverters. In order to have the same advantages for single phase
systems the vector control has been converted into a new topology, which works without the park
transformation. Therefore the new algorithm does not require much computing power and can be
utilised also in small inverters. Furthermore this algorithm provides a fictitious imaginary time
function which allows the complex calculation of sinusoidal functions. This makes it possible to
determine the instantaneous values of the modulus and the active and reactive power in single phase
systems. The developed and tested algorithms even do not require to detect the zero-crossing of
voltage and current. The combination of a precise control and the instantaneous availability of the
single phase quantities make active filtering easy and allow e. g. the parallel operation of voltage
source inverters without additional communication. The last feature is of great importance for the
expandability of renewable supply systems and for UPS-systems. Almost all of the introduced applications
have been tested successfully during the development of a battery inverter for renewable supply
systems. |
