Single phase UPS with FACTS capabilities by using p-q Theory

This paper proposes the use of an UPQC topology in a high efficiency single phase 1.4 kVA UPS system with active filter capabilities throughout the parallel and series converter. With this topology it is possible to obtain high efficiency and combine the advantages of both on-line and line interactive UPS systems and at the same time improving the grid energy quality. The series/parallel compensation references were generated using the p-q Theory which defines a joint of power definitions to deal with electric systems under non-sinusoidal conditions. Beyond that it provides a control strategy with a simplified model when compared with conventional d-q Theory. Accordingly to the simulation results it is shown that the system input current has a low THD and the system presents high power factor. Also, the load voltage has a sinusoidal shape with low THD both in its on-line and backup mode operation. Such simulations were developed in the software PSCAD/EMTDC.