scholarly journals Design of a High Efficiency High Step-Up/Step-Down Bidirectional Isolated DC–DC Converter

Processes ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 50
Author(s):  
Yu-En Wu ◽  
Pin-Jyun Lin
Keyword(s):  
Energy Conversion ◽  
High Efficiency ◽  
Low Voltage ◽  
Maximum Energy ◽  
Production Costs ◽  
Iron Core ◽  
Zero Voltage Switching ◽  
Bidirectional Converter ◽  
Step Down ◽  
Conversion Efficiencies

This paper presents a novel bidirectional DC–DC converter, equipped with a three-winding coupled inductor, that can be applied to high-voltage, bidirectional DC–DC energy conversion and meet battery charging and discharging requirements. The architecture consists of a semi-Z-source converter and a forward–flyback converter featuring a three-winding coupled inductor with an iron core. This proposed topology retains the current continuity characteristics of the low-voltage side, all switches possess the zero-voltage switching feature, and the switches on the low-voltage side in the step-down mode have a synchronous rectification function. A 500-W bidirectional converter is implemented to examine the practicality and feasibility of the proposed topology. The relatively streamlined design of the converter can greatly reduce production costs. In the step-up and step-down modes, the maximum energy conversion efficiencies are 95.74% and 96.13%, respectively.

scholarly journals Implementation of Snubber Circuits in a PV-Based Off-Grid Electric Vehicle Charging Station—Comparative Case Studies

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5853
Author(s):  
Divya Krishnan Nair ◽  
Krishnamachar Prasad ◽  
Tek Tjing Lie
Keyword(s):  
Low Voltage ◽  
Solar Array ◽  
Paradigm Shifts ◽  
Storage Unit ◽  
Charging Infrastructure ◽  
Energy Storage Unit ◽  
Leakage Inductance ◽  
Zero Voltage Switching ◽  
Charging Station ◽  
Bidirectional Converter

With the penetration of electric vehicles (EVs), there have been paradigm shifts in the transportation sector. EVs are ideally considered to be clean and eco-friendly, but they can overload the existing grid infrastructure and significantly contribute towards carbon emissions depending on the source of charging. The ideal solution is to develop a charging infrastructure for EVs that is integrated with solar energy technology. This paper presents the design of a zero-voltage switching snubber-based bidirectional converter for an off-grid charging station for EVs. The proposed system includes a solar array with a boost converter, a bidirectional converter with snubber circuits and an energy storage unit. A comprehensive comparison between various types of snubbers, such as the resistive capacitive diode snubber, active clamp snubber and flyback snubber, is presented. This type of system configuration clamps the rail voltage, due to the difference in current between leakage inductance and low voltage side-fed inductor currents, resulting in reduced current spikes at the converter’s switches. Such a converter, therefore, leads to higher efficiency of the charging station for EVs. The design of a snubber-based off-grid charging station for EVs is formulated and validated in the MATLAB/Simulink environment.

Pseudo-Capacitor Structure for Direct Nuclear Energy Conversion

2008 ◽  
Vol 1100 ◽  
Author(s):  
Liviu Popa-Simil
Keyword(s):  
Energy Conversion ◽  
Nuclear Power ◽  
Nuclear Energy ◽  
Nuclear Reactor ◽  
High Efficiency ◽  
Nuclear Reactors ◽  
Direct Conversion ◽  
Space Applications ◽  
Power Sources ◽  
Conversion Efficiencies

AbstractThe advanced space missions need for more power opened the way for advanced nuclear reactors and for alternative power conversion procedures. The most advanced power systems available in space are the fuel cells and nuclear reactors. Both systems manifest low efficiencies for converting the primary energy into electricity and as consequence are requiring high heat dump into space mainly by infrared radiation. The thermo-nuclear power generator also requires a high temperature gas turbine and a mechano-electric generator, finally driving to low conversion efficiencies. The new nano-materials offer the possibility of creating direct energy conversion devices able of achieving high conversion efficiencies up to 99% in the cryogenic versions. The interest for direct conversion of the nuclear energy into electricity appeared in early 1940th, by the invention of the thermo-ionic fission device by Linder. Then a series of patents and scientific papers improved gradually the designs and performances of the devices, up to the actual concepts of beta-voltaic and liquid-electronics. The most intuitive direct conversion device looks mainly like a super mirror- or a heterogeneous super-capacitor. The issues on its operation are related to global conversion efficiencies and the stable operation life-time in high radiation field. There are combinations of nano-structures and actinides assuring both the neutron flux stability, by meeting criticality conditions and the direct conversion or the nuclear energy into electricity. Achieving a high efficiency internal conversion of the nuclear energy into electricity is not enough if it is not completed by a high efficiency power extraction system from the nuclear reactor core into the outside load. The development of the new MEMS devices and micro electronics in the 40 nm technologies provides an excellent background for the production of the electric power harvesting and conversion devices embedded in the fuel. The new nano-structured materials may be produced as radiation energy harvesting tiles that are free of actinides, using them for harvesting the energy of radioactive sources and controlled fusion devices, or may include actinides in their structure achieving critical or sub-critical accelerator driven nuclear reactor assemblies. Another predictable advantage of the nano-structure is the property of self-repairing and self-organizing to compensate the radiation damage and improve the lifetime. Due to direct conversion the power density of the new materials may increase from the actual average of 0.2 kw/cm3 to about 1 kw/mm3 driving to miniaturization of nuclear power sources and reductions of the shield weight. At these dimensions and power densities of few thousands horse power per liter the nuclear power source becomes suitable for mobile applications as powering trains, strategic airplanes, etc. These new developments may drive to the production of high power solid-state compact nuclear battery for space applications, leading to a new development stage.

A New Interleaved Bidirectional Zero Voltage Switching DC/DC Converter with High Conversion Ratio

2017 ◽  
Vol 26 (06) ◽  
pp. 1750105 ◽  
Author(s):  
Ebrahim Babaei ◽  
Zahra Saadatizadeh ◽  
Behnam Mohammadi Ivatloo
Keyword(s):  
Power Flow ◽  
Low Voltage ◽  
Zero Voltage Switching ◽  
Bidirectional Converters ◽  
Comprehensive Comparison ◽  
Step Down ◽  
High Conversion Ratio ◽  
Bidirectional Power Flow ◽  
Zero Voltage ◽  
Voltage Switching

In this paper, a new interleaved nonisolated bidirectional zero voltage switching (ZVS) dc–dc converter by using one three-windings coupled inductor is proposed. The proposed topology can provide high step-up and high step-down conversion ratios for boost and buck operations, respectively. Moreover, because of interleaving, the proposed converter has low input current ripple at low voltage side in both buck and boost operations. The proposed converter uses lower number of switches to have bidirectional power flow in comparison with other interleaved bidirectional converters. All used switches in the proposed converter are turned on under ZVS. The advantages of the proposed converter in comparison with the conventional interleaved converters are included in the capability of bidirectional power flow, ZVS operation for all switches and high step-up and high step-down voltage gain for boost and buck operations. In this paper, the proposed converter is analyzed completely and all equations of components are extracted as well as the ZVS conditions of all switches. Moreover, a comprehensive comparison between the proposed converter and conventional topologies is presented. To verify the accuracy performance of the proposed converter, the experimental results are given.

High efficiency Bi2Te3-based materials and devices for thermoelectric power generation between 100 and 300 °C

2016 ◽  
Vol 9 (10) ◽  
pp. 3120-3127 ◽  
Author(s):  
Feng Hao ◽  
Pengfei Qiu ◽  
Yunshan Tang ◽  
Shengqiang Bai ◽  
Tong Xing ◽  
...  
Keyword(s):  
Power Generation ◽  
Temperature Gradient ◽  
Energy Conversion ◽  
Thermoelectric Power ◽  
Thermoelectric Materials ◽  
High Efficiency ◽  
Thermoelectric Power Generation ◽  
Conversion Efficiencies

High efficiency Bi2Te3-based thermoelectric materials and devices with energy conversion efficiencies of up to 6.0% under a temperature gradient of 217 K.

scholarly journals A Novel Soft-Switching Synchronous Buck Converter for Portable Applications

2008 ◽  
Vol 2008 ◽  
pp. 1-9
Author(s):  
Anup Kumar Panda ◽  
Swapnajit Pattnaik ◽  
K. K. Mohapatra
Keyword(s):  
Pulse Width ◽  
High Efficiency ◽  
Low Voltage ◽  
Buck Converter ◽  
Soft Switching ◽  
Pulse Width Modulated ◽  
Zero Voltage Switching ◽  
Overall Efficiency ◽  
Zero Voltage ◽  
Auxiliary Circuit

This paper proposes a zero-voltage-transition (ZVT) pulse-width-modulated (PWM) synchronous buck converter, which is designed to operate at low voltage and high efficiency typically required for portable systems. A new passive auxiliary circuit that allows the main switch to operate with zero-voltage switching has been incorporated in the conventional PWM synchronous buck converter. The operation principles and a detailed steady-state analysis of the ZVT-PWM synchronous converter implemented with the auxiliary circuit are presented. Besides, the main switch and all of the semiconductor devices operate under soft-switching conditions. Thus, the auxiliary circuit provides a larger overall efficiency. The feasibility of the auxiliary circuit is confirmed by simulation and experimental results.

scholarly journals Significant Influence of Annealing Temperature and Thickness of Electrode on Energy Conversion Efficiency of Dye Sensitized Solar Cell: Effect of Catalyst

2014 ◽  
Vol 39 ◽  
pp. 78-87 ◽  
Author(s):  
Jasim Uddin ◽  
Jahid M.M. Islam ◽  
Shauk M.M. Khan ◽  
Enamul Hoque ◽  
Mubarak A. Khan
Keyword(s):  
Solar Cell ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Annealing Temperature ◽  
High Efficiency ◽  
Energy Conversion Efficiency ◽  
Maximum Energy ◽  
Dye Sensitized Solar Cell ◽  
Great Promise ◽  
Dye Sensitized

Dye sensitized solar cell (DSSC) shows great promise as an alternative to conventional p-n junction solar cells due to their low fabrication cost and reasonably high efficiency. DSSC was assembled by using natural dye extracted from red amaranth (Amaranthus Gangeticus) as a sensitizer and different catalysts for counter electrode were applied for maximum energy conversion efficiency. Annealing temperature and thickness of electrode were also investigated and optimized. Catalyst, annealing temperature and thickness were optimized by the determination of cell performance considering photoelectrochemical output and measuring current and voltage; then calculating efficiency and other electrical parameters. The experimental results indicated that samples having 40 µm electrode thickness and prepared at 450 °C annealing temperature showed the best performance

scholarly journals Stability Prediction of Soft Switched Isolated DC-DC Converter

2019 ◽  
Vol 9 (2) ◽  
pp. 953-957
Keyword(s):  
High Efficiency ◽  
Low Voltage ◽  
Dynamic Performance ◽  
Stability Prediction ◽  
Leakage Inductance ◽  
Zero Voltage Switching ◽  
Power Semiconductor ◽  
Semiconductor Switches ◽  
Zero Voltage ◽  
Voltage Switching

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.

scholarly journals A High-Efficiency, Low-Cost Solution for On-Board Power Converters

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
V. Boscaino ◽  
G. Capponi
Keyword(s):  
Power Efficiency ◽  
High Efficiency ◽  
Low Voltage ◽  
Low Cost ◽  
Input Voltage ◽  
High Current ◽  
Forward Converter ◽  
System Cost ◽  
Zero Voltage Switching ◽  
Reset Voltage

Wide-input, low-voltage, and high-current applications are addressed. A single-ended isolated topology which improves the power efficiency, reduces both switching and conduction losses, and heavily lowers the system cost is presented. During each switching cycle, the transformer core reset is provided. The traditional tradeoff between the maximum allowable duty-cycle and the reset voltage is avoided and the off-voltage of active switches is clamped to the input voltage. Therefore, the system cost is heavily reduced and the converter is well suited for wide-input applications. Zero-voltage switching is achieved for active switches, and the power efficiency is greatly improved. In the output mesh, an inductor is included making the converter suitable for high-current, low-voltage applications. Since the active clamp forward converter is the closest competitor of the proposed converter, a comparison is provided as well. In this paper, the steady-state and small-signal analysis of the proposed converter is presented. Design examples are provided for further applications. Simulation and experimental results are shown to validate the great advantages brought by the proposed topology.

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