Design of High Efficiency Step-Down Converter for Electro Chemical Energy Conversion

Recently the research interest in power electronics interface for fuel cell has increased. And the static characteristics of fuel cells show more than a 30% difference in the output voltage between no-load to full-load conditions. Thus inevitable decrease, which is caused by internal losses, reduces the utilization of fuel cells at low loads. Fuel cell is a electrochemical energy conversion device which directly produces electricity. Thus, a step-down converter is required to transfer  from a high input  voltage  to an efficient and constant low level voltage. Maintaining high efficiency under a wide loading range is important in fuel cell.The aim of this work is to design a stepdown converter with DCM operation under light load not only can  reach high  efficiency  in heavy-load, but also has great improvement in light-load efficiency. The output accuracy and the output ripples obtained are better than other converters under light-load and as good as a normal PWM converter under heavy-load. Circuit simplicity and high reliability are the major advantages of the proposed converter. Using this technique, the utilization factor and efficiency of the fuel cell is increased. And this paper, focuses on the simulation and implementation of DC-DC converter fed fuel cell. Validation of the proposed model is verified through simulation. Keywords: Fuel cell, Stepdown converter, PW

Three-Phase Isolated Boost DC-DC Converter for High Voltage Applications

The voltage fed DC-DC converter has been suffering from problems associated with large transformer leakage inductance due to high transformer turn ratio when it is applied to low-voltage, high-current step-up application such as fuel cells. This paper proposes a new three-phase voltage fed DC-DC converter, which is suitable for high-voltage, high-current applications. The transformer turn ratio is reduced to half owing to ?-Y connection. The zero-voltage and zero-current switches (ZVZCS) for all switches are achieved over wide load range without affecting effective duty cycle. A clamp circuit not only clamps the surge voltage but also reduces the circulation current flowing in the high-current side, resulting in significantly reduced conduction losses. The duty cycle loss can also be compensated by operation of the clamp switch.The detailed design and operating principles are described and simulated using Pspice. The proposed converter is very attractive for electrolyser application.Keywords: High power DC–DC converter, three-phase DC-DC converter, active clamp circuit, Isolation transformer

A Comparative Analysis of Integrated Boost Flyback Converter using PID and Fuzzy Controller

This paper presents a comparative analysis of Integrated boost flyback converter for Renewable energy System. IBFC is the combination of boost converter and fly back converter. The proposed converter is simulated in open and closed loop using PID and FUZZY controller. The Fuzzy Logic Controller (FLC) is used reduce the rise time, settling time to almost negligible and try to remove the delay time and inverted response. The performance of IBFC with fuzzy logic controller  is found better instead of PID controller. The simulation results are verified experimentally and  the output of converter is free from ripples and has regulated output voltage

Simulation of AC-DC Converter for High Power Application

This manuscript deals with the simulation of AC - DC Zeta converter for high power drive application with greater efficiency, lesser losses and power factor correction. It involves simpler control circuitry with less external components. The explanation of Fundamental function of Zeta converter is given in this paper. To condense the harmonic content the PI, PID and Fuzzy Logic controller are used. The operation of Zeta converter in open loop, closed loop is obtained. Closed loop system of zeta converter proves better performance over open loop system. Open and closed loop circuits are simulated by using MATLAB simulink. By giving disturbance in closed loop and open loop systems, feat of Zeta converter is compared.