High step‐up DC–DC converter with low power device voltage stress for a distributed generation system

Abstract

This study presents a novel step-up DC-DC converter with the coupled inductor and low switch voltage stress, which reduce diode voltage stress. The presented converter contains single switch, four diodes, four capacitors and one coupled inductor. When switch is turned ON, the primary side of coupled inductor is charged by the input source. Besides, the primary and secondary side of the coupled inductor is discharged in series with the input source and two capacitors to realise the high step-up voltage gain when the switch is turned OFF. Furthermore, the clamped circuit which adopts two capacitors negative pole connection not only recycles leakage energy and obtains the high voltage conversion gain, but also is realised to reduce the voltage stress of the diode, which can be use low-voltage rated devices with low on-resistance. In addition, the three diodes are working on the zero-current-switching turn-off, therefore, the loss is reduced and the reverse-recovery problem is avoided. The current falling rate of the output diode is effectively restricted for the leakage inductor, therefore, its reverse-recovery problem is effectively alleviated. Finally, a 40 V input voltage, 380 V output voltage and 400 W output power prototype circuit is established in the laboratory to verify the performance.