Duty‐cycle‐controlled resonant dual‐half‐bridge converter with multifunctional capacitors for distributed generation applications

This study describes a duty-cycle-controlled resonant dual-half-bridge converter with multifunctional capacitors for enhancing the voltage level of fuel cell and photovoltaic sources to 380 V. Owing to the incorporation of dc-link capacitors and leakage inductance into two various resonant circuits, both switches turn-on under the zero-voltage-switching circumstance and turn-off with low current because of quasi-resonant operation. Since the currents of diodes are controlled by the leakage inductances of transformers, it is not obligatory for a designer to employ the diodes with reverse-recovery current specification; consequently, less expensive diodes can be adopted. The complementary effects of series-connected secondary windings of transformers and switched-capacitor circuits result in forming the balanced voltage multiplier stage, augmenting the voltage conversion ratio substantially without the need for utilising a transformer having higher turns ratio; so, one of the magnificent factors of growth of the conduction losses has been avoided. Ultimately, the results of the laboratory prototype operating with 58 kHz switching frequency, 18 V input voltage, 380 V output voltage, and 500 W output power prove that the proposed topology would be proficient to fulfil its function in systems using distributed generation resources.