Transformerless Common-Mode Current-Source Inverter Grid-Connected for PV Applications

The use of a transformer in grid-connected photovoltaic (PV) generation systems provides isolation between the grid and the PV array, this increases the cost, weight, and the size of the system. However, the transformer elimination increases the efficiency and the security issues, these should be taken into account, but also to remove the isolation leads the apparition of a leakage current due to the PV parasitic capacitance to the ground. This paper presents a five-switch common-mode current-source inverter for grid-connected applications and a control scheme based on finite control set, where an additional force section is considered, in order to regulate the current injected to the grid. The proposed topology can reduce the leakage current in photovoltaic systems due to the common mode connection. The operation modes, consideration design, control technique, and the simulation results are presented.