In this paper, a new non-isolated multi-input step-up converter is presented. By implementing a new switching algorithm in the proposed topology, the converter output voltage, as well as the power absorbed from each source, can be controlled independently, resulting in a simple controller, which is a distinctive virtue for this converter in comparison to similar multi-input converters. Current sharing between various sources is achieved independently. No need to control different parameters of switches' gate-source voltage such as the delay between switches and thus independent maximum power point tracking (MPPT) algorithm can be used for each input source. Providing soft-switching condition and transferring power from all inputs to the load independently are other features of this converter. Operating modes of the converter as well as experimental results obtained for a 300 W prototype for supplying stand-alone load are presented.

In this paper, a new zero-voltage switching and resonant core reset pulse width modulation forward converter with a simple auxiliary circuit is introduced. The proposed auxiliary circuit can be applied to both single-switch and two-switch forward converters. The main and the auxiliary mosfets of the proposed converters operate under soft switching condition independent of line and load variation. Also, due to the capability of operating at duty cycles higher than 0.5, the proposed converters can be used for wide input voltage applications. In comparison to the existing zero-voltage transition (ZVT) forward converters, this auxiliary circuit has low number of components and also does not require any additional magnetic element which has improved the power density. The proposed converter is compared with exiting ZVT forward converters in details. The converter steady-state operation is analyzed and various operating modes are explained. Also, in addition to a design example, a comprehensive design procedure is presented. The experimental results of a laboratory prototype of the converter with 85-180 V input voltage and 24 V output voltage at 150 W are provided which verify the theoretical analysis and confirm the converter operation. The overall efficiency of 93.5% is achieved for the proposed converter at full load.

In this article, a novel soft switched interleaved boost structure with a simple auxiliary circuit is proposed which is suitable for stand-alone loads or ac grid applications. In this topology, coupled inductors and switched capacitor cells of parallel modules are merged to obtain high voltage conversion ratio. The converter also has the capability of adding extra switched capacitor cells to attain very high voltage gain. To provide soft-switching condition in the wide range of output power, a new zero-voltage transition auxiliary circuit is employed which is responsible for soft switching of both phases and benefits from low conduction losses, the minimum number of semiconductor elements, and only one auxiliary gate-driver. These merits provide very high efficiency at both full-load and light loads. More importantly, no auxiliary magnetic components are utilized by taking advantage of the leakage inductance of coupled inductors for the resonant network. All semiconductor components operate under soft switching alleviating the reverse recovery problem and switching losses. Besides, the converter benefits from common ground between input and output which simplify voltage feedback. The experimental results of the interleaved converter prototype with 400-V output voltage at 400 W and 100 kHz switching frequency are provided. The full load efficiency of 98% was achieved and the power density was observed 1.9 W/Cm ³ .

This paper presents a novel single-switch soft-switching high step-up DC-DC boost converter. By utilizing a coupled inductor and series capacitors in the output stage, the converter achieves soft switching performance for the power switch during turn-on and turn-off, along with a high step-up voltage gain. The design of the coupled inductors enables simultaneous achievement of soft switching and high voltage gain without the need for additional auxiliary circuits, ensuring circuit simplicity and high efficiency. Furthermore, the converter maintains continuous input current, similar to a boost converter, improving battery lifespan and renewable input power source operation. The proposed converter addresses diode reverse recovery issues and incorporates a common ground between input and output stages, simplifying the feedback circuit. Comparative analysis with similar high-efficiency high step-up boost converters is performed, and a 200W laboratory prototype is implemented.

In this paper a high-efficiency, high step-up DC-DC converter is introduced utilizing a new soft switching circuit based on the zero voltage transition (ZVT) technique. Soft switching performance is independent of the output load and input voltage. The simple auxiliary circuit benefits from a low number of components. The resonant circuit comprises merely one switch and one small capacitor and in comparison to the existing ZVT high step-up converters, no extra auxiliary diode and resonant inductor are used to provide soft switching. The proposed auxiliary circuit can be applied to coupled-inductors based step-up topologies, because of exploiting the leakage inductance of the coupled-inductor cell in the resonant network. Providing soft switching performance for all the semiconductor elements alleviates the reverse recovery and switching losses, which considerably enhances the efficiency. The proposed topology is a competitive structure in terms of efficiency, voltage gain ratio, and the number of components due to the mentioned features. The theoretical results are validated on a 200 W laboratory prototype with a 400 V output voltage.

This article proposes a new nonisolated, interleaved, high step-up, soft-switching converter for renewable energy applications. The proposed converter is a boost topology designed to have a continuous input current with low ripple. It employs no auxiliary circuit or extra switches to achieve soft-switching, and the voltage stress on the power switches is reduced. By using the transformer's leakage inductance, the power diodes’ reverse recovery current problem is tackled without the need for an extra snubber circuit. The proposed converter has been analyzed and compared with similar topologies. Experimental results from a 400-W prototype with a 30–300 V conversion ratio are presented, demonstrating the effectiveness of the proposed converter, which is well-suited for use with renewable energy sources.