Compartilhamento otimizado de energia aplicável a um sistema delta-ups trifásico operando no modo de operação backup

Abstract

This work proposes the implementation of strategies for sharing the energy handled by the series and parallel power converters, which compose a three-phase Delta uninterruptible power supply (UPS) system. Thus, since a three-phase system is considered, by using additional static switches, operating in association with the proposed strategies for powersharing, the overall amount of active and non-active power processed by the PWM converters can be optimized when the UPS operates in backup-mode. Usually, for a conventional operation of the Delta-UPS in standby operation mode, the power processed by the series and parallel converters are always lower than that demanded by the load, such that both converters operate underload. On the other hand, in the backup mode, the series converter is inhibited, while the parallel converter remains feeding the load, such that the parallel converter must be sized to provide all the power demanded by the load. It can be highlighted that by employing the strategies proposed in this paper, the series converter is not inhibited in backup mode and operates in conjunction with the parallel converter. Therefore, the power compensation algorithms predict an effective power sharing between the converters, based on the amount of energy demanded by the load. As a result, the sizing of the parallel converter can be optimized, since its nominal VA power rate does not need to be equal to that demanded by the load. Simulation and experimental results are performed in order to present the effectiveness of the proposed optimized power sharing strategies.