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A novel zero voltage switching (ZVS) interleaved high step-up converter with for renewable energy systems is proposed in this paper. By applying a switched capacitor mixed with coupled inductor and built-in transformer, the proposed converter achieves high voltage gain and minimized voltage stress across power switches. Both of the voltage gain and the voltage stress, can be adjusted by the turns ratio of the coupled inductor and built-in transformer which gives an extra degree of freedom for the converter design. Hence operating at high duty cycles is avoided and low voltage rated semiconductors can be adopted which reduce conduction losses and improve the circuit performance. Furthermore, active clamp scheme is utilized to guarantee ZVS turn ON for the power MOSFETs and the leakage inductances of the magnetic means help to provide zero current switching (ZCS) of the diodes. In such a case, switching losses are minimized and the reverse current recovery is alleviated. Accordingly, the proposed converter with reduced counterparts is a suitable candidate for high step-up and high power applications. Finally, a 600W prototype with 24V-480V voltage conversion is built to demonstrate the performance of the proposed converter.

In this article, we propose a novel interleaved high step-up converter. The proposed converter integrates the built-in transformer voltage multiplier cell (VMC) to the interleaved boost converter with voltage lift capacitor. The voltage gain is increased by both of the turns ratio of the built-in transformer and the voltage lift capacitor. Hence, there is no need to operate the converter around unity duty cycles to obtain high voltage gains. Meanwhile, the voltage stress across semiconductors is reduced considerably, facilitating the utilizing of mosfet s with low on -state resistance and diodes with low forward voltage drop decreasing the conduction losses. The leakage inductance of the built-in transformer not only provides zero current switching (ZCS) for mosfet s but also controls the falling current rate of the diodes alleviating the reverse current recovery problem. In addition, the energy of the leakage inductance is recycled by the clamp capacitor avoiding high spikes across switches. In comparison with the recently published converters, the proposed converter introduces all of the abovementioned advantages with a low number of components that make it an interesting solution for high efficiency and high step-up applications. Finally, a 40-V to 580-V prototype with 930 W power is fabricated to explore the merits of the proposed converter.

A new scheme of single-phase transformerless grid-connected inverter is presented in this article. By employing the series–parallel switching conversion of the integrated switched-capacitor module in a packed unit, some attractive features for the proposed inverter can be obtained. Such promising features can be quantified as more than 97% overall efficiency for a wide range of output power, two-time boosting ability within a single-stage operation and almost total suppression of the leakage current through using the common grounding technique. In this case, a peak current controller strategy is used in order to trigger the gate of power switches and control both the active and reactive powers. Therefore, a tightly controlled current with an appropriate quality can be injected to the grid from a single source renewable energy resource. Operating procedure, design consideration, comparison study, and a 513 W built prototype results are also given to prove the correctness and feasibility of the proposed circuit.

This article proposes a novel step-up interleaved dc–dc converter that is suitable for renewable energy systems. Coupled inductor and built-in transformer voltage multiplier cell are applied to extend the voltage gain while increasing the power density. Hence, the step-up ratio can be adjusted by the turns ratios of the coupled inductor and the built-in transformer. Compared with the other converters with only built-in transformer or only coupled inductor, the combination of these techniques gives an extra degree of freedom to increase the voltage gain. The configuration of the proposed converter not only reduces the current stress through the components, but also the input current ripple is maintained at low values that lengthen the life time of the renewable power source. The energy of the leakage inductors is successfully recycled and the high-voltage spikes across the power switches are avoided, which improves the conversion efficiency. Due to the reduced voltage stress, low-voltage power MOSFET s can be adopted for reduction of conduction losses and cost. The principle operation and steady-state analysis are given to explore the advantages of the proposed converter. Finally, a 1-kW prototype with 45–675 V voltage conversion is built to demonstrate the effectiveness of the proposed converter.

This paper presents an interleaved converter that benefits the coupled inductor and built-in transformer voltage multiplier cell (VMC). Compared with the other converters with only a built-in transformer or only a coupled inductor, the combination of these techniques gives an extra degree of freedom to increase the voltage gain. The VMC is composed of the windings of the built-in transformer and coupled inductors, capacitors, and diodes. The voltage stress of MOSFETs is clamped at low values and can be controlled via the turns ratio of the built-in transformer and coupled inductor that increases the design flexibility. Moreover, the energy of the leakage inductances, is recycled to the clamp capacitors which avoids high voltage spikes across MOSFETs. In addition, the current falling rate of the diodes is controlled by the leakage inductances, and the reverse current recovery problem is alleviated. Meanwhile, due to the interleaved structure of the proposed converter, the input current ripple is minimized and the current stress of the power devices is decreased. All of these factors improve the efficiency of the proposed converter in high-current and high-voltage applications. The principle operation and steady-state analysis is given to explore the advantages of the proposed converter. Finally, a 1.3-kW prototype with 50–600 V voltage conversion is built to demonstrate the effectiveness of the proposed converter.

This paper presents an interleaved nonisolated dc–dc converter with high-voltage gain and zero-voltage switching (ZVS) performance. Both coupled inductor and voltage multiplier cell techniques are used to increase the voltage gain. The ZVS circuit is composed of an active clamp which is in series with the output filter capacitors. This will give rise to further extension of the voltage gain. Applying the interleaving technique at the input of the converter, the ripple of the input current is reduced. Due to the leakage inductances of coupled inductors, the diodes are turned-off under zero-current switching condition. Hence, the reverse current recovery problem is alleviated. The steady-state analysis of the proposed converter is also presented. Finally, a 900-V to 415-W laboratory prototype is implemented to validate the performance of the proposed converter.

The aim of this paper is to present a new structure for switched-capacitor multilevel inverters (SCMLIs) which can generate a great number of voltage levels with optimum number of components for both symmetric and asymmetric values of dc-voltage sources. The proposed topology consists of a new switched-capacitor dc/dc converter (SCC) that has boost ability and can charge capacitors as self-balancing by using the proposed binary asymmetrical algorithm and series–parallel conversion of power supply. The proposed SCC unit is used in new configuration as a submultilevel inverter (SMLI) and then, these proposed SMLIs are cascaded together and create a new cascaded multilevel inverter (MLI) topology that is able to increase the number of output voltage levels remarkably without using any full H-bridge cell and also can pass the reverse current for inductive loads. In this case, two half-bridge modules besides two additional switches are employed in each of SMLI units instead of using a full H-bridge cell that contribute to reduce the number of involved components in the current path, value of blocked voltage, the variety of isolated dc-voltage sources, and as a result, the overall cost by less number of switches in comparison with other presented topologies. The validity of the proposed SCMLI has been carried out by several simulation and experimental results.