A grid-connected PV power system with high step-up ZVT interleaved boost converter

A grid-connected photovoltaic (PV) power system with the high step-up ZVT interleaved boost converter is presented in this paper. For a typical PV module, the output voltage is relatively low. So the high voltage gain is obligatory to realize the grid-connected function. The proposed PV system employs a ZVT interleaved boost converter with an active-clamp circuit as the first power processing stage, which can boost a low voltage of PV array up to the high DC bus. And a full bridge inverter with bidirectional power flow is used as the second power processing stage, which can stabilize the DC bus voltage and shape the output current. Two compensation units are added to perform in system control loops and low THD of the current is achieved. In addition a simple sensor-less MPPT method is applied in the PV system and represents a good performance. At last, a 1.5-kW prototype was built and tested to verify the theoretical analysis of the paper.