ISOLATED HIGH STEP-UP ZERO-VOLTAGE-SWITCHING DC-DC CONVERTER WITH A CONTINUOUS INPUT CURRENT

2011 ◽  
Vol 20 (08) ◽  
pp. 1619-1635 ◽  
Author(s):  
HYUN-LARK DO

An isolated high step-up DC-DC converter with a continuous input current is proposed. The proposed converter consists of two converter cells — a boost converter cell at the input stage for a low input current ripple and a DC-DC converter cell for high voltage gain. Zero-voltage-switching of power switches are achieved and the leakage inductance of the transformer alleviates the reverse-recovery problems of the output diodes. Therefore, the proposed converter achieves high efficiency. Detailed analysis and design of the proposed converter are carried out. A prototype of the proposed converter is developed, and its experimental results are presented for validation.

Mathematical analysis and stability prediction of soft switched isolated dc-dc converter is presented in this paper. Half bridge dc-dc converter is an attractive topology for low voltage applications due to its simplicity, lower cost, improved reliability and enhanced dynamic performance. Both power semiconductor switches of the proposed isolated converter operate asymmetrically under Zero Voltage Switching (ZVS) to achieve high efficiency and low voltage stress. Furthermore, the ringing resulted from the oscillation between the transformer leakage inductance and the junction capacitance of two switches is eliminated. Conversion efficiency is also improved by providing synchronous rectifier with very small output filter. The operating principle, state space analysis and control strategy of proposed converter is explained with small signal model. Experimental results are presented to explain the zero voltage switching capability and stability features of proposed converter.


2016 ◽  
Vol 839 ◽  
pp. 65-69
Author(s):  
Sakda Somkun ◽  
Shanmugham Prabhuraj ◽  
Chatchai Sirisamphanwong

This paper presents the analysis and design of a dual active bridge DC-DC converter for fuel cell applications. The zero voltage switching operating condition of such converter is analyzed to select an appropriate turn ratio of the high frequency transformer for a high efficiency operation. The ratio between the output voltage to the fuel cell voltage should be close to the transformer turn ratio to guarantee the zero voltage switching regimes at a light load. The prototype converter was designed to be suitable for the input voltage of 40 to 65 V and output voltage of 360 to 400 V with the transformer turn ratio of 7.33. The converter was tested with a 48 V DC power supply and with a polymer electrolyte membrane fuel cell stack. The maximum power of 700 W was delivered and the efficiency was better than 94% for the whole load range.


Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 272
Author(s):  
Hyeon-Seok Lee ◽  
Jae-Jung Yun

This paper presents a highly efficient three-port converter to integrate energy storage (ES) and wireless power transfer (WPT) systems. The proposed converter consists of a bidirectional DC-DC converter and an AC-DC converter with a resonant capacitor. By sharing an inductor and four switches in the bidirectional DC-DC converter, the bidirectional DC-DC converter operates as a DC-DC converter for ES systems and simultaneously as a DC-AC converter for WPT systems. Here, four switches are turned on under the zero voltage switching conditions. The AC-DC converter for WPT system achieves high voltage gain by using a resonance between the resonant capacitor and the leakage inductance of a receiving coil. A 100-W prototype was built and tested to verify the effectiveness of the converter; it had a maximum power-conversion efficiency of 95.9% for the battery load and of 93.8% for the wireless charging load.


Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2154
Author(s):  
María R. Rogina ◽  
Alberto Rodríguez ◽  
Aitor Vázquez ◽  
Diego G. Lamar ◽  
Marta M. Hernando

This paper is focused on the design of a control approach, based on the detection of events and changing between two different conduction modes, to reach high efficiency over the entire power range, especially at medium and low power levels. Although the proposed control strategy can be generalized for different topologies and specifications, in this paper, the strategy is validated in a SiC-based synchronous boost DC/DC converter rated for 400 V to 800 V and 10 kW. Evaluation of the power losses and current waveforms of the converter for different conduction modes and loads predicts suitable performance of quasi-square wave mode with zero voltage switching (QSW-ZVS) conduction mode for low and medium power and of continuous conduction Mode with hard switching (CCM-HS) for high power. Consequently, this paper proposes a control strategy, taking advantage of digital control, that allows automatic adjustment of the conduction mode to optimize the performance for different power ranges.


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