Simulation of an inverter working as an active power filter and as an auxiliary power supply

This paper presents the simulation of a three-phase-four legs inverter working as an active power filter while the source voltage feeds the load, and functions as an Auxiliary Power Supply (APS) during a power system failure. This work consists in introducing an energy storage element linked to the three-phase inverter by means of a dc/dc bidirectional converter. This dc/dc converter works as a ¿buck¿ converter while the battery is recharged or as a ¿boost¿ converter when the battery supplies the load. The aim of this configuration is to reduce the bulky and heavy of the batteries bank. The new system (inverter, dc/dc converter and battery) has to work then in one of the following two modes according to the availability of the electric system: as an active power filter and battery charger if the grid is available, or as an APS and boost if the grid is unavailable.