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A dual switches high step‐up DC–DC converter with coupled inductor (CI) and voltage multiplier cell (VMC) is proposed in this paper. The gate pulses of the switches are synchronized with each other. During ON state of the switches, the CIs are charged in parallel through the input power source and during OFF state of the switches, they are discharged to the output in series. The energy of the leakage inductances is recycled by the passive clamp circuit. The passive clamp circuit for one of the metaloxidesemiconductor field‐effect transistor (MOSFETs) is integrated with the VMC. In such a case, the clamp circuit participates in voltage gain extension which facilitates the utilization of lower number of the components, as well. Meanwhile, the MOSFETs and diodes are turned ON and turned OFF with zero current switching (ZCS) performance which reduces the switching losses. Through the dual switches concept and implementation of the CI VMC, the advantages such as high voltage gain, low voltage stresses across switches and distributed current stresses between MOSFETs are achieved. The steady‐state analysis of the proposed converter is provided which is followed by a comparison with some published converters. Finally, a 300 W 25V to 400 V laboratory prototype is fabricated and tested to verify the performances. [ABSTRACT FROM AUTHOR]

This paper proposes a soft‐switching high step‐up DC/DC interleaved boost converter. The converter uses an interleaved structure to decrease input current ripple. The coupled inductor technique achieves high voltage gain without needing the extremely increased duty cycle. The applied auxiliary circuit provides zero‐voltage‐switching (ZVS) condition for both main switches with a minimum number of elements. In addition, all the diodes turn off with zero‐current‐switching (ZCS), alleviating the reverse recovery problem. Moreover, all power switches and diodes have low voltage stress. The voltage stress of the auxiliary switch is low, resulting in low Coss losses of the auxiliary switch. The other properties of the proposed converters are continuous‐low‐ripple input current, no need for the floating gate drive, and small size. The theoretical analysis is validated by a 250‐W prototype with 40‐V input to 400‐V output voltage with a 100‐kHz.switching frequency. [ABSTRACT FROM AUTHOR]

By inserting the secondary windings of the coupled inductors in series with the primary of the built‐in transformer at the middle branch, a new concept is introduced for achieving ultra large voltage gain. The secondary and tertiary windings of the built‐in transformer are inserted in the voltage multiplier cell. This configuration not only extends the voltage gain and minimises the voltage stress across power MOSFETs, but also gives a more flexibility to increase the voltage gain by the turns ratios of the built‐in transformer and coupled inductors. Hence, high duty cycle is avoided and low voltage switches can be adopted which reduces the conduction losses. Also, the regenerative diode in each of the phases is connected to the other phase to improve equal current sharing performance. The energy of the leakage inductances is recycled by passive clamps and the high voltage spikes are avoided. Meanwhile, due to the leakage inductances of the magnetic means, the zero current switching of semiconductor devices is provided and the reverse recovery problem is alleviated. Finally, a 600 W prototype with 28–400 V voltage conversion and 97% conversion efficiency is built to demonstrate the performance of the converter. [ABSTRACT FROM AUTHOR]