Common-Mode Voltage Reduction Method-Based Flexible Power Control for Multiport DC–AC Converter in PV–Battery Hybrid System

The multiport dc–ac converter (MPC) connected to photovoltaic (PV)–battery hybrid system has the characteristics of high efficiency and low cost in single-stage power conversion. However, it is challenging to achieve common-mode voltage (CMV) reduction in this configuration due to its need for power distribution through redundant vectors. To overcome this limitation, this article proposes an improved space vector modulation (ISVM) method to reduce the CMV and achieve flexible power distribution. By selecting vectors with lower CMVs, a set of new virtual voltage vectors based on the power control parameter is generated. In addition, to further realize flexible power distribution among PV, battery, and load, a new control scheme is proposed to achieve power balance in different operating modes under CMV reduction. The highlight of the method is its ability to achieve power distribution and lower CMV simultaneously. Finally, compared to conventional methods, the simulated and experimental results prove that the proposed method can realize CMV reduction, flexible power control with variable port voltages.