Multi-port single-phase inverter considering battery-alone mode for stand-alone applications

This paper presents a new single-phase multi-port DC-AC converter with high voltage gain in low duty cycle. The operation of the proposed converter consists of four modes, especially battery-alone mode, which makes it appropriate for stand-alone renewable applications. Using a suitable boosting method, this converter can achieve high voltage gain in all modes. The high gain performance of the converter occurs at both low shoot-through duty cycle and high modulation index. Therefore, the output voltage and current harmonics as well as the filter size are reduced. In addition, the converter transfers the power with a continuous current through its input ports and has a common ground between the input sources and the inverter bridge. The positive features of this converter are the result of the appropriate design and localization of the bidirectional port that connects the battery to the converter. The proposed configuration includes an impedance network that protects the converter in the shoot-through states and takes the advantage of the shoot through in its boosting performance. Another advantage of the proposed converter is that the voltage stress on the power switches on the DC side is considerably low. In order to validate the feasibility and effectiveness of the converter, a prototype rated at 110 V is prepared and tested.