scholarly journals Ultracapacitors Utilization for Automotive Applications

10.14311/1153 ◽  
2010 ◽  
Vol 50 (1) ◽  
Author(s):  
Z. Pfof ◽  
P. Vaculík
Keyword(s):  
Fuel Cell ◽  
High Efficiency ◽  
Soft Switching ◽  
Drive Unit ◽  
Basic Principles ◽  
Zero Voltage Switching ◽  
Zero Current Switching ◽  
Zero Current ◽  
Zero Voltage ◽  
Very High

This paper describes the basic properties of ultracapacitors and a converter for ultracapacitors with application zero-voltage switching (ZVS). Because of the very high efficiency of the ultracapacitor, the efficiency of the converter for ultracapacitors also has to be high; otherwise, the converter reduces efficiency of the whole drive unit. Further, the paper describes the drive unit concept for the CityEl electric vehicle, with the use of ultracapacitors in cooperation with a fuel cell. This co-operation with ultracapacitors is useful for the supply unit as a fuel cell, which cannot deliver peak power in dynamic conditions while maintaining its nominal efficiency. However, this poses no problems for ultracapacitors.There is also a description of the basic principles of soft switching using zero-voltage and zero-current switching together with a comparison of the power losses between hard and soft switching. 

scholarly journals An Interleaved DC/DC Converter with Soft-switching Characteristic and high Step-up Ratio

2020 ◽  
Vol 10 (6) ◽  
pp. 2167
Author(s):  
Yong-Nong Chang ◽  
Hung-Liang Cheng ◽  
Hau-Chen Yen ◽  
Chien-Hsuan Chang ◽  
Wei-Di Huang
Keyword(s):  
Conversion Efficiency ◽  
Operation Mode ◽  
Soft Switching ◽  
Switching Characteristic ◽  
Boost Converters ◽  
Zero Voltage Switching ◽  
Zero Current Switching ◽  
Zero Current ◽  
Current Ripples ◽  
Zero Voltage

This study presents a dc/dc converter featuring soft-switching characteristic, high conversion efficiency, and high step-up ratio. The proposed circuit is composed of two parallel-connected boost converters. Only one coupled inductor is used to replace inductors of the boost converters which are interleaved operated at discontinuous-conduction mode (DCM). The current ripples at the input and the output terminals are reduced due to the interleaved operation. By freewheeling the current of the coupled inductor to discharge the stored electric charges in the parasitic capacitors of the active switches, both active switches can fulfill zero-voltage switching on (ZVS). Owing to DCM operation, the freewheeling diodes can fulfill zero-current switching off (ZCS). Therefore, the power conversion efficiency is improved. The operation principle for each operation mode is analyzed in detail and design equations for the component parameters are provided in this report. Finally, a prototype 200 W 48–400 V converter was implemented and measured to demonstrate the effectiveness of the proposed circuit.

scholarly journals Analysis, Design and Experimental Validation of Modified Simple Soft Switching DC-DC Boost Converter

2015 ◽  
Vol 16 (4) ◽  
pp. 331-337 ◽  
Author(s):  
S. Raghavendran ◽  
B. Chitti Babu ◽  
Luigi Piegari
Keyword(s):  
Theoretical Analysis ◽  
Experimental Validation ◽  
Soft Switching ◽  
Zero Voltage Switching ◽  
Switching Losses ◽  
Zero Current Switching ◽  
Zero Current ◽  
Analysis Design ◽  
Zero Voltage ◽  
Voltage Switching

Abstract This paper investigates a modified simple soft switching dc-dc converter for low power applications. This simple topology uses an auxiliary switch, an inductor and a capacitor to operate the converter without switching losses. The efficiency of the converter is improved by transferring the energy that would be dissipated during the switching to the load. The main switch turns-on with zero current switching (ZCS) and turns-off with zero voltage switching (ZVS), while the auxiliary switch turns-on and turns-off with zero voltage switching (ZVS). The detailed theoretical analysis and the design equations are described. In addition to that, the analysis of proposed converter is demonstrated by both simulation and experimental results for effectiveness of the study.

Non-Isolated High Step-up DC-DC Converter with a Coupled Inductor

2012 ◽  
Vol 424-425 ◽  
pp. 1024-1027 ◽  
Author(s):  
Hyun Lark Do
Keyword(s):  
High Efficiency ◽  
Semiconductor Devices ◽  
Soft Switching ◽  
Voltage Gain ◽  
Switching Loss ◽  
Switching Operation ◽  
Zero Voltage Switching ◽  
Zero Current Switching ◽  
Zero Current ◽  
And Performance

A non-isolated high step-up DC-DC converter with a coupled inductor is proposed in this paper. The proposed converter provides high voltage gain and soft-switching operation of all semiconductor devices. A voltage doubler and a coupled inductor increase the voltage gain. Zero-voltage-switching (ZVS) of all switches and zero-current-switching (ZCS) of all diodes are achieved. Also, the voltages across the semiconductor devices are effectively clamped. Due to the soft-switching operation of all switching devices, the switching loss is significantly reduced and the high efficiency is obtained. The feasibility and performance of the proposed converter were verified on an experimental prototype

scholarly journals Performance of Isolated Soft Switching Current Fed Lcc-T Resonant Dc-Dc Converter for Pv/Fuel Cell Applications

2020 ◽  
Vol 10 (1) ◽  
pp. 1-4
Keyword(s):  
Fuel Cell ◽  
High Harmonic ◽  
Soft Switching ◽  
Voltage Transformer ◽  
Constant Frequency ◽  
Zero Voltage Switching ◽  
Switching Current ◽  
Load Demand ◽  
Zero Current Switching ◽  
Zero Current

In this paper, the design and evaluation of isolated soft switching current LCC-T Resonant DC-DC Converter for PV/Fuel cell applications. For the front end inverter switches, zero voltage switching (ZVS) is used for conversion. For voltage double diodes, Zero-Current Switching (ZCS) is used. Earlier, DC-DC converter provides high harmonic currents, so to overcome that, proposed converter is introduced. The proposed converter will improve the content of harmonic current based on the input variations and wide load. To get the required output voltage, transformer ration will be reduced. Because of the, for PV/ Fuel cell applications have better foot Print and high potential. The proposed converter operates in two modes mainly; they are constant frequency mode and constant duty cycle mode. These modes mainly depend on the load demand. At last from results it can observe that gives satisfying proposed theory.

scholarly journals Comparative Evaluation of Wide-Range Soft-Switching PWM Full-Bridge Modular Multilevel DC–DC Converters

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 231 ◽  
Author(s):  
Jingwen Chen ◽  
Xiaofei Li ◽  
Hongshe Dang ◽  
Yong Shi
Keyword(s):  
Comparative Evaluation ◽  
Soft Switching ◽  
Load Range ◽  
Zero Voltage Switching ◽  
Zero Current Switching ◽  
Zero Current ◽  
Wide Range ◽  
Switching Characteristics ◽  
Structure Indices ◽  
Zero Voltage

This paper discusses some wide-range soft-switching full-bridge (FB) modular multilevel dc–dc converters (MMDCs), and a comparative evaluation of these FB MMDCs is also presented. The discussed topologies have all merits belonging to conventional FB MMDCs, e.g., smaller voltage stress on the primary switches, no added primary clamping devices and modular primary structure. In addition, the primary switches in each converter can obtain zero-voltage switching (ZVS) or zero-current switching (ZCS) in a wide load range. Two presented topologies are selected as examples to discuss in detail. The proposed FB MMDCs are assessed and evaluated based on performance, components and topology structure indices, such as soft switching characteristics, current stress, power loss distribution, number of added devices, complexity of structure and added cost. Experimental results are also included to verify the feasibility and advantages of the new topologies.

scholarly journals Simple Structure of Soft Switching for Boost Converter

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5448
Author(s):  
Yeu-Torng Yau ◽  
Kuo-Ing Hwu ◽  
Jenn-Jong Shieh
Keyword(s):  
Frequency Control ◽  
Resonance Method ◽  
Boost Converter ◽  
Soft Switching ◽  
Constant Frequency ◽  
Zero Voltage Switching ◽  
Current Switching ◽  
Zero Current Switching ◽  
Zero Current ◽  
Zero Voltage

A soft switching boost converter, with a small number of components and constant frequency control, is proposed herein by using the quasi-resonance method and the zero-voltage-transition method, realizing (1) the zero-voltage switching during the switch-on transient of the main switch, (2) the zero-current switching during the switch-off transient of the main switch, (3) the zero-current switching during the switch-on transient of the auxiliary switch, and (4) the zero-current switching during the switch-off transient of the auxiliary switch. Accordingly, the corresponding efficiency can be improved. The feasibility and effectiveness of the proposed structure are validated by the field programmable gate array (FPGA).

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