New high step-up DC-DC converter for photovoltaic grid-connected applications

In this paper a new high step-up DC-DC converter suitable for photovoltaic applications is investigated. Boosting the low input voltage in the proposed topology is implemented by using coupled inductors and one semiconductor switch. By using a passive regenerative clamp circuit, the energy of leakage inductor is absorbed and this provides a wider possible range of output power. Moreover, using just one semiconductor switch with low voltage rating and soft turn on, results in lower switching losses and therefore higher efficiency. In this topology, bipolar outputs are generated and by connecting the negative terminal of the PV module to the output neutral point, the unwanted ground leakage currents in the PV systems is reduced drastically. Easy control due to employing one MOSFET switch is another feature of this topology. Theoretical analysis and principal operation of the circuit are discussed. An experimental prototype is implemented to verify the performance of the proposed inverter. The experimental results confirm the aforementioned features and the theoretical analysis of the converter operation.