Fuel Cell Energy Source Research Articles

Implementation of a dual input DC-DC boost converter for solar and fuel cell integration with a smart grid

This research involves the implementation of a dual-input DC-DC boost converter for integrating solar and fuel cell energy sources with a smart grid. The growing demand for renewable energy sources necessitates the efficient utilization and integration of multiple energy systems. The proposed dual-input converter enables simultaneous extraction and management of power from solar panels and fuel cells, resulting in improved energy generation and utilization. The converter incorporates a smart grid interface, allowing bidirectional power flow between the energy sources and the grid. The design and control strategy of the dual-input converter are discussed in detail, with a focus on achieving high conversion efficiency, maximum power point tracking, and optimal power sharing between the solar panels and fuel cells. The control algorithm utilizes a combination of Perturb and Observe (P&O) and Incremental Conductance (IncCond) methods for Maximum Power Point Tracking (MPPT), ensuring efficient power extraction from the solar panels. Additionally, a Proportional-Integral (PI) controller is implemented to regulate power flow between the energy sources and the grid. Simulation and experimental results are presented to validate the proposed converter's performance under various operating conditions.

State-Feedback Control of Interleaved Buck–Boost DC–DC Power Converter with Continuous Input Current for Fuel Cell Energy Sources: Theoretical Design and Experimental Validation

It is well known that the classical topologies of Buck–Boost converters drain pulsating current from the power source. These pulsating currents entail acceleration of the aging rate of the fuel cell. In this paper, we are considering a Buck–Boost DC–DC converter topology featuring continuous input current. The converter interleaved structure ensures the substantial increase in power density compensating power losses related to the converter switching nature. The control objective is to enforce the DC-bus voltage to track its desired value despite load uncertainties and to ensure adequate current sharing between the different parallel modules of the fuel cell interleaved Buck–Boost converter (FC-IBBC). The point is that the internal voltage of the fuel cell is not accessible for measurement. Therefore, the state-feedback control, which consists of nonlinear control laws, is designed on the basis of a nonlinear model of the FC-IBBC system. We formally prove that the proposed controller meets its objectives, i.e., DC-bus voltage regulation and equal current sharing. The theoretical proof relies on the asymptotic stability analysis of the closed-loop system using Lyapunov stability tools. The theoretical results are well confirmed both by simulation, using MATLAB®/Simulink®, and by experimental tests using DS 1202 MicroLabBox.

Real-time implementation of adaptive nonlinear control of Buck-Boost DC-DC power converter with a continuous input current for fuel cell energy sources

Classical Buck-Boost converter (BBC) topologies are known to drain a pulsating current from the input power source which accelerates the aging rate of the fuel cell (FC). In this paper, a Buck-Boost DC-DC converter topology with continuous input current is used. In addition to its input current, the converter offers the advantage of using a reduced number of electronic components. The point is that the internal voltage of the fuel cell is not accessible for measurement. Therefore, based on a nonlinear model of the FC-BBC system, an adaptive nonlinear controller based on the Backstepping technique is developed to meet the following requirements: (i) tracking the DC-bus voltage to its desired value despite the load uncertainties, (ii) asymptotic stability of the closed-loop system using Lyapunov stability tools. The advantage of the proposed control strategy lies in its simplicity compared to the existing nonlinear approaches. Detailed analysis, simulation, and experimental tests show that the proposed controller meets all control objectives, namely: tight dc-bus voltage regulation and asymptotic stability of the closed-loop system. The effectiveness of the proposed approach is verified by simulation using MATLAB® / Simulink®, and by experimental tests using DS 1202 MicroLabBox.

A Dual Source Switched-Capacitor Multilevel Inverter with Reduced Device Count

Implementing voltage boost multilevel inverter topologies for PV and fuel cell energy sources is highly advantageous. Switched-capacitor multilevel inverters (SCMLI) have a step-up feature with low device requirements and can remove the need for high gain dc-dc converters leading to reduced overall system bulk. This work proposes a dual input SCMLI to achieve an output of nineteen levels while using a low number of components and high boosting factor and self-balancing of capacitor voltages. A comprehensive analysis of the proposed structure is presented, focusing on component requirements, cost and dynamic performance. The efficiency and loss distribution during operation is also provided. The operation and real-time performance of the SCMLI have been verified by simulation. Experimental results further validate the simulation results.

High Step-Up Converter With Three-Winding Coupled Inductor for Fuel Cell Energy Source Applications

This paper presents a high step-up converter for fuel cell energy source applications. The proposed high step-up dc-dc converter is devised for boosting the voltage generated from fuel cell to be a 400-V dc-bus voltage. Through the three-winding coupled inductor and voltage doubler circuit, the proposed converter achieve high step-up voltage gain without large duty cycle. The passive lossless clamped technology not only recycles leakage energy to improve efficiency but also alleviates large voltage spike to limit the voltage stress. Finally, the fuel cell as input voltage source 60-90 V integrated into a 2-kW prototype converter was implemented for performance verification. Under output voltage 400-V operation, the highest efficiency is up to 96.81%, and the full-load efficiency is 91.32%.

Utilization of fuel cell energy source for distribution power generation: theory, modeling and review of research work

The energy crisis is one of the most critical phenomena happening in today's world. The depletion of fossil fuels, the rise in oil prices, and the increase in power demand are the main causes of this problem. Concern over environmental conditions and human health make renewable energy one of the most viable alternative solutions to this crisis. Among various types of renewable energy, fuel cell technology shows a great potential in the electrical energy sector for several reasons, such as high efficiency, clean operation, and immunity to the adverse effects of weather conditions. Recent works prove that fuel cell technology is expected to be a better choice for distributed generation purposes. Distributed generation, which is installed near load centers, can moderate the stress of high electricity demand in the mainstream utility grid. This paper presents an overview of fuel cell technology, with emphasis on fuel cell types, characteristics, and applications. The differences among the various fuel cell types and the dynamic models of each type required for simulation are also discussed. Focus is given to the application of fuel cells in a distributed generation system, the requirements of a fuel cell-based generating system, and issues in distributed generation integration. The present study also discusses the power conditioning unit, which is an important component in the fuel cell-based generating system, as well as its control strategy. Discussion is likewise made on the use of suitable energy storage units for the fuel cell distributed generation system, with regard to battery types and storage control. By adding energy storage units to the fuel cell system, the capabilities of the existing generation system can improve system stability performance. Streszczenie. W artykule zaprezentowano przegląd technologii wytwarzania energii z wykorzystaniem ogniw paliwowych koncentrując sie na analizie roznych typow i ich zastosowan. Szczegolną uwage zwrocono na zastosowanie ogniw paliwowych w rozproszonych systemach wytwarzania energii. Analizowano tez uklad kondycjonowania energii oraz jego sterowanie. Wykorzystanie ogniw paliwowych w rozproszonych systemach wytwarzania energii elektrycznej - teoria, modelowanie i przegląd prac badawczych

가정용 연료전지 시스템의 단독운전 시 부하설비의 전압 및 전력품질 평가

Recently, due to the excessive use of fossil fuels, many studies about the fossil fuels such as solar and fuel cell energy source are progressing. Fuel cell system has high energy conversion efficiency. Also, fuel cell system is environmentally friendly system because the carbon emission is almost not occur. Therefore, the fuel cell system is considered as the core technology of in the fields of the future energy and environmental. Fuel cell system has an effect on distribution power system because another power source of other than large power plants. So, fuel cell system can be reason of power quality in the power system. In this paper, we constructed the system for an assessment on Islanding. The system is composed with power source, Impedance coordination load and linear load, fuel cell system. we are performed assessment on voltage and power quality in customer and the distributed power system during the Islanding of residential fuel cell system. In addition, no change in the impedance of power system, we made a islanding condition only using the actual load, As a variation of generation and load current under islanding, an analysis results based on assessment system showed that the power qualities of distribution system became more aggravation as effect of voltage sag and voltage swell phenomena.

가정용 연료전지 시스템의 계통연계 시 수용가 및 배전계통에서의 고조파 영향 평가

Recently, due to the use of fossil fuels for electric power production, carbon emissions increased excessively. Thereby, in order to replace fossil fuels, many studies about fossil fuels such as solar and fuel cell energy source are progressing. Fuel cell system has high energy conversion efficiency. Also, fuel cell system is environmentally friendly system because the carbon emission is almost not occur. Therefore, the fuel cell system is considered as the core technology of in the fields of the future energy and environmental. Fuel cell system has an effect on distribution power system because another power source of other than large power plants. So, fuel cell system can be degradation reason of power quality in the power system. In this paper, we constructed the system for an assessment on harmonics effect. The system is composed with power source, harmonics generation and linear load, fuel cell system. we also performed assessment on harmonics effect in customer and the distributed power system during grid connection of residential fuel cell system. An assessment cases are divided into three. A Case 1 is state that residential load and fuel system are connected to grid, Case 2 is state that residential load and harmonics load are connected to grid, and Case 3 is state that all loads are connected to grid. As a output of fuel cell system is increase, analysis results based on assessment system showed that power quality became more aggravation as effect of harmonics.

폴리이미드 중공사막을 이용한 혼합기체로부터 H2S 제거 및 CO2/CH4분리에 관한 연구

본 연구는 막 분리 공정을 이용한 것으로 수소의 에너지원을 이용가능한 메탄을 정제하기 위해 바이오가스 중 이산화탄소와 메탄의 분리 및 황화수소의 제거하고자 한다. 막은 건/습식 상전이 법을 이용하여 중공사공 형태로 제조하고 표면 실리콘 코팅 후 모듈을 제조하였다. 제조된 중공사 막의 구조특성을 확인하기 위해 전자주사 현미경 관찰을 통하여 치밀한 표면과 망상구조의 비대칭 구조를 확인하였다. 압력과 온도가 증가함에 따라 이산화탄소의 투과도는 증가하였고, 이산화탄소와 메탄의 선택도 역시 증가하는 것으로 나타났다. 혼합가스의 경우 압력 및 온도가 증가함에 따라 메탄 농도는 100%에 가까웠으며 이산화탄소와 황화수소의 제거효율도 증가하였다. Retentate 유량증가와 압력 온도감소에 따라 메탄 농도 감소 및 회수율이 증가하는 경향을 나타내었다. In this study, by using the polymeric membrane separation process, the <TEX>$CO_{2}/CH_{4}$</TEX> separation and <TEX>$H_{2}S$</TEX> removal from biogas were performed in order to <TEX>$CH_{4}$</TEX> purification and enrichment for the fuel cell energy source application. Fibers were spun by dry/wet phase inversion method. The module was manufactured by fabricating fibers after surface coating with silicone elastomer. The scanning electron microscopy(SEM) studies showed that the produced fibers typically had an asymmetric structure; a dense top layer supported by a porous, sponge substructure. The permeance of <TEX>$CO_{2}$</TEX> and <TEX>$CO_{2}/CH_{4}$</TEX> selectivity increased with pressure and temperature. Mixture gas with increasing pressure and temperature, removal efficiency of the <TEX>$CO_{2}$</TEX> and <TEX>$H_{2}S$</TEX> were decreased while concentration of <TEX>$CH_{4}$</TEX> was increased up to 100%. When retentate flow rate was increased with the decreasing of pressure and temperature the <TEX>$CH_{4}$</TEX> recovery ratio in retentate side was increased while the <TEX>$CH_{4}$</TEX> purity in retentate side was decreased.

High-Efficiency Power Conversion for Low Power Fuel Cell Generation System

This study presents a newly designed topology for a fuel cell energy source conversion in order to supply a highly reliable utility power. Because the fuel cell has the power quality of low voltage as well as high current due to the electrochemical reaction, a high step-up dc-dc converter is utilized for boosting the fuel cell voltage up to a constant dc-bus voltage for the utilization of later inverter. Moreover, a current-source sine-wave voltage inverter is designed in the sense of voltage-clamping and soft-switching techniques to enable the use of a smaller inductor in the current source circuit and the compression of the voltage stress across switches about two times of the dc-bus voltage. In this power conversion scheme, the output voltage has the salient features of lower distortion, fast dynamic regulating speed and insensitivity to load variation, even under nonlinear loads. In addition, experimental results via an example of a proton exchange membrane fuel cell generation system with 250-W nominal power rating are given to demonstrate the effectiveness of the proposed power conversion strategy. According to the experimental measure, the maximum power inverter efficiency is over 95% and the total harmonic distortions for various load conditions are all within 1.1%.

Electrical Power Control and Conditioning Subsystem for the Manned Orbital Research Laboratory (MORL)

The electrical power control and conditioning subsystem developed under NASA* Contract NASl-4479 represents an integrated, operational design for the Manned Orbital Research Laboratory (MORL) to support 6 men in space for 5 years. The power conditioning systems discussed in recent engineering papers have generally been planned for unmanned craft or were for optimizations of specific electrical loads of modest demand levels, and used conventional battery, solar cell/battery, or fuel cell energy sources. Therefore, an advanced design to supply a greater (by an order-of-magnitude) electrical demand from a radioisotope-dynamic generator drive system, and which meets manned spacecraft design criteria, represents a significant and unique contribution to aerospace electrical design. This paper identifies and discusses (1) the unique electrical design criteria and constraints associated with the radioisotope Brayton cycle drive system, (2) the tradeoff considerations which were necessary to optimize the total system with respect to speed, frequency, and efficiency, (3) the rationale for the selection of the alternator and the frequency converters, and (4) the distribution system design criteria which were established to assure flexibility, efficiency, maintainability, and safe emergency operations. The control system concept and its integration with the energy storage subsystems will also be discussed.