On-Grid Photovoltaic System Using A Solid-State Transformer

This paper explains a single-phase on-grid PV
system employing a solid-state transformer (SST) which consists
of a DC-AC converter, a high-frequency transformer, a simple
rectifier, and a Voltage Source Inverter (VSI). The DC-AC
converter converts the PV panel output voltage to a highfrequency
three-level square wave required by the transformer
operation. The pulse width of the square wave determines the
PV operating points. The high-frequency transformer provides
voltage level matching and galvanic isolation between the PV
panels and the grid. While a simple rectifier produces a DC bus
voltage for the VSI. The VSI has a grid current controller and a
DC bus voltage controller to regulate the electrical power flow
of the grid, the load, and the PV panel. Computer simulation
results prove that the PV power can be delivered to the load and
the grid through SST, while the grid current is kept sinusoidal
and in phase with the grid voltage