APPLICATION OF UTILITY INTERACTIVE PHOTOVOLTAIC POWER-GENERATION SYSTEM FOR UPS

The paper proposes the application of PV system for uninterruptible po wer supply (UPS), The PV system is composed of a novel single-phase PW M voltage source inverter (VSI). Composite PWM method is achieved by a circuit configuration consisting of the normal single-phase bridge ci rcuit and an additional arm, which contributes to reduce the ripple in the AC output current. The VSI has a LC series-resonance circuit tune d to twice the utility frequency connected in parallel with the smooth ing capacitor, The series-resonance circuit absorbs the double-frequen cy AC components included in the DC pulsated current. Hence, the smoot hing capacitor is drastically reduced. A storage battery is added on t he DC side in order to stabilize DC voltage. The VSI is easily changed from inverter action to rectifier action by changing the firing angle alpha from plus to minus. When alpha is minus, the VSI acts as a batt ery charger.