Boost and full‐bridge integrated converter for wide input‐voltage range application

The output voltage of fuel and solar cells varies extensively and is often low. Thus, high step-up DC-DC converters in DC microgrid should be suitable for an extensive input-voltage range application. However, the voltage stress of rectifier diodes is high in an extensive voltage range in voltage-source converters. In addition, the input current of the converter should be continuous to obtain a high lifetime of fuel cell and to realize maximum power point tracking (MPPT) for the PV array. Output current of the converter should be continuous to use a film capacitor, which can improve the lifetime and reliability of the converter. Thus, a boost and full-bridge integrated converter is proposed. Switches in the boost converter are shared with the full-bridge converter to reduce the number of switches. Since transformer secondary to primary turns ratio is reduced compared to voltage-source converters, voltage stress of rectifier diodes is low. As there are input and output inductors in the proposed converter, input and output currents are continuous. Operating principle is elaborated. Design guidelines and example are illustrated. The loss calculation of the proposed converter is given. Finally, simulation and experimental results confirm the theoretical analysis. The proposed converter can be used in the wide input-voltage range application.