Search

In this article, a novel dual active clamp converter with high voltage gain is proposed for dc–dc applications. The active clamps’ switches turn on and off under zero-current switching (ZCS). In addition, the main switch turns on under ZCS condition, as well. Therefore, switching losses are significantly reduced. The converter is also capable of operating under quasi-resonance (QR) mode. In this mode, switching losses are reduced further by lowering the voltage and current, at which the main switch turns off. In comparison with the conventional interleaved converter, the voltage gain of the proposed converter is almost the same, but the number of semiconductors and switching loss are significantly reduced. The switching frequency of the active clamps’ switches is half of the main switching frequency. The operation principles of the proposed converter are studied in both pulsewidth modulation and QR modes, and the advantages are investigated. A 200-W prototype is implemented to validate the desired functionality of the converter, and experimental results are compared in both modes. [ABSTRACT FROM AUTHOR]

A novel semi-isolated high step-up double-input converter with current-fed inputs is introduced in this study. The proposed converter can operate in double-input mode and single-input mode. It can manage the collected power from both inputs effectively. In addition, it makes a gentle transition between the modes, without the need for an abrupt change in pulse pattern, and does not utilise a breaker switch. Meanwhile, the converter preserves soft-switching as well as a few number of semiconductors (three switches and three diodes). These items have improved the efficiency of the converter to 94.5%. Moreover, it is a high-voltage gain (more than 13). Also, both input ports are current-fed, so the input currents are smoothed. These features make the converter compatible with hybrid renewable energy applications. Furthermore, all components are engaged in both modes, which results in an improved component's utilisation factor. A thorough analysis has been conducted to prove the characteristics mentioned above of the proposed converter. Theoretical analysis has been verified by simulation and experimental results of a 200 W prototype. [ABSTRACT FROM AUTHOR]

A new partly isolated three-port converter is introduced in this study for hybrid energy applications. Two boost circuits form the main input port and a bidirectional battery port of the converter. Therefore, both of them are of a current-fed type, making the converter more suitable for renewable energy applications. In addition, the boost circuits are benefited from a mutual active clamp circuit. The circuit in cooperation with the leakage inductance of transformers provides soft switching, while employing a few number of semiconductors. Furthermore, on the secondary side, two voltage-doubler rectifiers are merged. As a result, the converter employs less number of components, which participate in all power conversion modes. Since most of the renewable energy sources have a relatively low voltage level, the converter retains high voltage gain. These features have resulted in an efficient and inexpensive converter. A thorough analysis has been made and justified by simulation and experimental results. [ABSTRACT FROM AUTHOR]

A high voltage gain dual interleaved full bridge converter with Zero Voltage Switching (ZVS), improved integrated magnetics, and a new resonant Switched-Capacitor-Cell (RSC) is presented. By taking the advantage of a new resonant switched capacitor cell and transformers with low turn-ratio as well as low leakage inductances, the desired high output voltage can be obtained. Furthermore, the output diodes operate in Zero Current Switching (ZCS) condition, and switches are maintained under ZVS condition over the whole range of output load variations. In addition, switches turn off near zero current leading to high overall efficiency. An interleaved approach (multi-cell) is adopted over a single cell to increase the power handling capacity. Furthermore, transformers of dual cells are integrated into a single UU core which cuts down the total volume of the converter as well as the total core loss. Since secondary windings have opposite polarities, there exists no DC flux, and the top and bottom RSC cells operate in 180 degree out of phase. Taking the aforementioned characteristics into consideration, the proposed converter has a good performance for high voltage applications. Experimental results of a 3 kw prototype with an output voltage of 16 kV validate the features of this topology. [ABSTRACT FROM AUTHOR]