Development of High Performance Micro DMFCS and a DMFC Stack

2005 ◽  
Vol 3 (2) ◽  
pp. 131-136 ◽  
Author(s):  
G. Q. Lu ◽  
C. Y. Wang
Keyword(s):  
Power Density ◽  
Silicon Wafer ◽  
Output Power ◽  
Oxygen Transport ◽  
Maximum Output Power ◽  
Maximum Power ◽  
Membrane Electrode ◽  
Maximum Output ◽  
Maximum Power Density ◽  
Air Breathing

A silicon-based micro direct methanol fuel cell (μDMFC) for portable applications has been fabricated and its electrochemical characterization carried out. A membrane-electrode assembly (MEA) was specially fabricated to mitigate methanol crossover. The cell with active area of 1.625cm2 demonstrated a maximum power density of 50mW∕cm2 at 60°C. Since the silicon wafer is too fragile to compress for sealing, and a thicker layer of gold has to be coated on the silicon wafer to reduce contact resistance, further development of micro DMFCs for high power application was carried out using stainless steel as bipolar plate in which flow channels were fabricated by photochemical etching technology. The maximum power density of the micro DMFC reaches 62.5mW∕cm2 at 40°C and 100mW∕cm2 at 60°C with atmospheric pressure. An 8-cell air-breathing DMFC stack has been developed. Mass transport phenomena such as water transport and oxygen transport were investigated. By using a water management technique, cathode flooding was avoided in our air-breathing DMFC stack. Furthermore, it was found that oxygen transport in the air-breathing cathode is still very efficient. The DMFC stack produced a maximum output power of 1.33W at 2.21V at room temperature, corresponding to a power density of 33.3mW∕cm2. A passive DMFC using pure methanol was demonstrated with steady-state output power of 20-25mW∕cm2 over more than 10h without heat management.

Development of High Performance Micro DMFCs and a DMFC Stack

2005 ◽  
Author(s):  
Guoqiang Lu ◽  
Chao-Yang Wang
Keyword(s):  
Power Density ◽  
Silicon Wafer ◽  
Output Power ◽  
Oxygen Transport ◽  
Maximum Output Power ◽  
Maximum Power ◽  
Membrane Electrode ◽  
Maximum Output ◽  
Maximum Power Density ◽  
Air Breathing

A silicon-based micro direct methanol fuel cell (μDMFC) for portable applications has been fabricated and its electrochemical characterization carried out. A membrane-electrode assembly (MEA) was specially fabricated to mitigate methanol crossover. The cell with the active area of 1.625 cm2 demonstrated a maximum power density of 50 mW/cm2 at 60°C. Since silicon wafer is too fragile to compress for sealing, and a thicker layer of gold has to be coated on the silicon wafer to reduce contact resistance, further development of micro DMFCs for high power application was carried out using stainless steel plate as bipolar plate in which flow channels were fabricated by photochemical etching technology. The maximum power density of the micro DMFC reaches 62.5 mW/cm2 at 40 °C and 100 mW/cm2 at 60°C with atmospheric pressure. An 8-cell air-breathing DMFC stack has been developed. Mass transport phenomena such as water transport, and oxygen transport were investigated. By using a water management technique, cathode flooding was avoided in our air-breathing DMFC stack. Furthermore, it was found that oxygen transport in the air-breathing cathode is still very efficient. The DMFC stack produced a maximum output power of 1.33 W at 2.21 V at room temperature, corresponding to a power density of 33.3 mW/cm2. A passive DMFC using pure methanol was demonstrated with steady-state output power of 20–25 mW/cm2 over more than 10 hours without heat management.

scholarly journals Pengaruh Algoritma Peturb & Observe pada Irradiance, Suhu dan Beban Bervariasi

AVITEC ◽  
2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Ernando Rizki Dalimunthe
Keyword(s):  
Output Power ◽  
Maximum Output Power ◽  
Maximum Power ◽  
Maximum Output ◽  
Average Output ◽  
Point Tracking ◽  
Power Simulation ◽  
Power Point Tracking ◽  
Duty Cycles ◽  
Power Point

Optimizing the output power value of a solar cell requires a tracker. The tracking is called the maximum power point tracking (MPPT) which will produce a maximum output power value. Each component in this system is modeled into Simulink. This simulation is designed to optimize the work of solar cells by searching maximum power points using perturb and observe (P & O) algorithms, then duty cycles are output  of the algorithms become Buck-Boost Converter inputs as switching so they can produce output power with better output  power. Simulation results show that MPPT can increase the average output power on changes in the value of sun irradiation, temperature and load than systems that do not use MPPT. The factor of the average difference in power is 37.82%.

scholarly journals Finite Time Thermodynamic Optimization of an Irreversible Proton Exchange Membrane Fuel Cell for Vehicle Use

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 419 ◽  
Author(s):  
Changjie Li ◽  
Ye Liu ◽  
Bing Xu ◽  
Zheshu Ma
Keyword(s):  
Power Density ◽  
Output Power ◽  
Proton Exchange Membrane ◽  
Operating Temperature ◽  
Maximum Output Power ◽  
Proton Exchange ◽  
Maximum Output ◽  
Operating Pressure ◽  
Output Efficiency ◽  
Exchange Membrane

A finite time thermodynamic model of an irreversible proton exchange membrane fuel cell (PEMFC) for vehicle use was established considering the effects of polarization losses and leakage current. Effects of operating parameters, including operating temperature, operating pressure, proton exchange membrane water content, and proton exchange membrane thickness, on the optimal performance of the irreversible PEMFC are numerically studied in detail. When the operating temperature of the PEMFC increases, the optimal performances of PEMFC including output power density, output efficiency, ecological objective function, and ecological coefficient of performance, will be improved. Among them, the optimal ecological objective function increased by 81%. The proton film thickness has little effect on the output efficiency and the ecological of coefficient performance. The maximum output power density increased by 58% as the water content of the proton exchange membrane increased from 50% to the saturation point. The maximum output power density increases with the operating pressure.

4H-SiC Planar MESFETs on High-Purity Semi-Insulating Substrates

2007 ◽  
Vol 556-557 ◽  
pp. 763-766 ◽  
Author(s):  
Jeong Hyuk Yim ◽  
Ho Keun Song ◽  
Jeong Hyun Moon ◽  
Han Seok Seo ◽  
Jong Ho Lee ◽  
...  
Keyword(s):  
Power Density ◽  
Output Power ◽  
High Purity ◽  
Maximum Output Power ◽  
Drain Current ◽  
Maximum Output ◽  
Power Gain ◽  
Si Substrates ◽  
Class A ◽  
Current Instability

Planar MESFETs were fabricated on high-purity semi-insulating (HPSI) 4H-SiC substrates. The saturation drain current of the fabricated MESFETs with a gate length of 0.5 μm and a gate width of 100 μm was 430 mA/mm, and the transconductance was 25 mS/mm. The maximum oscillation frequency and cut-off frequency were 26.4 GHz and 7.2 GHz, respectively. The power gain was 8.4 dB and the maximum output power density was 2.8 W/mm for operation of class A at CW 2 GHz. MESFETs on HPSI substrates showed no current instability and much higher output power density in comparison to MESFETs on vanadium-doped SI substrates.

Influence of electrical impedance and mechanical bistability on Galfenol-based unimorph harvesters

2016 ◽  
Vol 28 (3) ◽  
pp. 421-431 ◽  
Author(s):  
Zhangxian Deng ◽  
Marcelo J Dapino
Keyword(s):  
Power Density ◽  
Output Power ◽  
Maximum Output Power ◽  
Element Model ◽  
Maximum Energy ◽  
Bistable System ◽  
Maximum Output ◽  
Base Excitation ◽  
Frequency Bandwidth ◽  
Electrical Loads

A study on iron-gallium (Galfenol) unimorph harvesters is presented which is focused on extending the power density and frequency bandwidth of these devices. A thickness ratio of 2 (ratio of substrate to Galfenol thickness) has been shown to achieve maximum power density under base excitation, but the effect of electrical load capacitance on performance has not been investigated. This article experimentally analyzes the influence of capacitive electrical loads and extends the excitation type to tip impulse. For resistive-capacitive electrical loads, the maximum energy conversion efficiency achieved under impulsive excitation is 5.93%, while the maximum output power and output power density observed for a 139.5 Hz, 3 [Formula: see text] amplitude sinusoidal base excitation is 0.45 W and 6.88 [Formula: see text], respectively, which are 8% higher than those measured under purely resistive loads. A finite element model for Galfenol unimorph harvesters, which incorporates magnetic, mechanical, and electrical dynamics, is developed and validated using impulsive responses. A buckled unimorph beam is experimentally investigated. The proposed bistable system is shown to extend the harvester’s frequency bandwidth.

scholarly journals A Novel Configuration of A Microstrip Power Amplifier based on GaAs-FET for ISM Applications

2018 ◽  
Vol 8 (5) ◽  
pp. 3882
Author(s):  
Amine Rachakh ◽  
Larbi El Abdellaoui ◽  
Jamal Zbitou ◽  
Ahmed Errkik ◽  
Abdelali Tajmouati ◽  
...  
Keyword(s):  
Output Power ◽  
Power Amplifier ◽  
Return Loss ◽  
Maximum Output Power ◽  
Maximum Power ◽  
Design System ◽  
Stability Factor ◽  
Maximum Output ◽  
Power Gain ◽  
Microstrip Technology

Power Amplifiers (PA) are very indispensable components in the design of numerous types of communication transmitters employed in microwave technology. The methodology is exemplified through the design of a 2.45GHz microwave power Amplifier (PA) for the industrial, scientific and medical (ISM) applications using microstrip technology. The main design target is to get a maximum power gain while simultaneously achieving a maximum output power through presenting the optimum impedance which is characteristically carried out per adding a matching circuit between the source and the input of the power amplifier and between the load and the output of the power amplifier. A "T" matching technique is used at the input and the output sides of transistor for assure in band desired that this circuit without reflections and to obtain a maximum power gain. The proposed power amplifier for microwave ISM applications is designed, simulated and optimized by employing Advanced Design System (ADS) software by Agilent. The PA shows good performances in terms of return loss, output power, power gain and stability; the circuit has an input return loss of -38dB and an output return loss of -33.5dB. The 1-dB compression point is 8.69dBm and power gain of the PA is 19.4dBm. The Rollet's Stability measure B1 and the stability factor K of the amplifier is greater than 0 and 1 respectively, which shows that the circuit is unconditionally stable. The total chip size of the PA is 73.5× 36 mm2.

scholarly journals Implementasi MPPT Panel Surya Berbasis Algoritma Perturbasi & Observasi (PO) Menggunakan Arduino

2021 ◽  
Vol 2 (2) ◽  
pp. 162-167
Author(s):  
Haris Masrepol ◽  
Muldi Yuhendri
Keyword(s):  
Control System ◽  
Output Power ◽  
Output Voltage ◽  
Maximum Output Power ◽  
Buck Converter ◽  
Maximum Power ◽  
Maximum Output ◽  
Solar Panels ◽  
Maximum Power Point ◽  
Power Point

Solar panels are a renewable energy power plant that uses sunlight as its main energy source. The power generated by solar panels are determined by the size of the solar panels, solar radiation and temperature. The power of the solar panels is also determined by the output voltage of the solar panels. To get the maximum output power at any time, it is necessary to adjust the output voltage of the solar panel. This study proposes controlling the maximum output power of solar panels, also known as maximum power point tracking (MPPT) by adjusting the output voltage of the solar panels using a buck converter. The buck converter output voltage regulation at the maximum power point of the solar panel is designed with the Perturbation and Observation (PO) algorithm which is implemented using an Arduino Mega 2560. This MPPT control system is applied to 4x50 Watt-Peak (WP) solar panels which are connected in parallel. The experimental results show that the proposed MPPT control system with the PO algorithm has worked well as expected. This can be seen from the output power generated by the solar panels already around the maximum power point at any change in solar radiation and temperature.

scholarly journals The effectivness of using a non-platinum material combination for the catalyst layer of a proton exchange membrane fuel cell

2016 ◽  
Author(s):  
◽  
Dwayne Jensen Reddy
Keyword(s):  
Fuel Cell ◽  
Flow Field ◽  
Power Density ◽  
Catalyst Layer ◽  
Test Cell ◽  
Maximum Power ◽  
Polymer Electrolyte Fuel Cell ◽  
Membrane Electrode ◽  
Maximum Power Density ◽  
Flow Rates

The effectiveness of using a low cost non - platinum (Pt) material for the catalyst layer of a polymer electrolyte fuel cell (PEMFC) was investigated. A test cell and station was developed. Two commercial Pt loaded membrane electrode assemblies (MEA) and one custom MEA were purchased from the Fuelcelletc store. Hydrogen and oxygen were applied to either side of the custom MEA which resulted in an additional sample tested. An aluminium flow field plate with a hole type design was manufactured for the reactants to reach the reaction sites. End plates made from perspex where used to enclose the MEA, flow field plates, and also to provide reactant inlet and outlet connection points. The developed test station consisted of hydrogen and oxygen sources, pressure regulators, mass flow controllers, heating plate, and humidification units. A number of experimental tests were carried out to determine the performance of the test cells. These tests monitored the performance of the test cell under no-load and loaded conditions. The tests were done at 25 °C and 35 °C at a pressure of 0.5 bar and varying hydrogen and oxygen volume flow rates. The no-load test showed that the MEA’s performed best at high reactant flow rates of 95 ml/min for hydrogen and 38 ml/min for oxygen. MEA 1, 2, 3, and 4 achieved an open circuit voltage (OVC) of 0.936, 0.855, 0.486 and 0.34 V respectively. The maximum current density achieved for the MEAs were 0.3816, 0.284, 15x10-6, and 50x10-6 A/cm2. Under loaded conditions the maximum power densities achieved at 25 °C for MEA’s 1, 2, 3, and 4 were 0.05, 0.038, 2.3x10-6, 1.99x10-6 W/cm2 respectively. Increasing the temperature by 10°C for MEA 1, 2, 3, 4 resulted in a 16.6, 22.1, 1.79, 10.47 % increase in the maximum power density. It was found that increasing platinum loading, flow rates, and temperature improved the fuel cell performance. It was also found that the catalytic, stability and adsorption characteristics of silver did not improve when combining it with iridium (Ir) and ruthenium oxide (RuOx) which resulted in low current generation. The low maximum power density thus achieved at a reduced cost is not feasible. Thus further investigation into improving the catalytic requirements of non Pt based catalyst material combinations is required to achieve results comparable to that of a Pt based PEMFC.

Modified Fuzzy Logic MPPT for PV System under Severe Climatic Profiles

2021 ◽  
Vol 4 (2) ◽  
pp. 49-55
Author(s):  
Rao Muhammad Asif ◽  
Muhammad Abu Bakar Siddique ◽  
Ateeq Ur Rehman ◽  
Muhammad Tariq Sadiq ◽  
Adeel Asad
Keyword(s):  
Fuzzy Logic ◽  
Output Power ◽  
Fuzzy Logic Controller ◽  
Maximum Output Power ◽  
Management Control ◽  
Maximum Power ◽  
Effective Control ◽  
Maximum Output ◽  
Pv System ◽  
Battery Bank

Photovoltaic energy is considered highly favorable due to the environment's pleasant nature. After analyzing different maximum power point tracking (MPPT) algorithms, an effective control scheme is proposed to obtain stabilized maximum output power throughout the PV system. Therefore, this article presents an efficient control algorithm for the extraction of maximum power through a PV system under severe climatic drifts. The modified fuzzy logic controller sustains the maximum output power of the system by defining fuzzy rules to control the duty cycle appropriately. A DC-DC boost converter is also modeled to stabilize and maintain output power under variant climatic uncertainties. Furthermore, charging management control is also implemented on lead-acid battery bank to store PV energy for backup usage. It defines charging-discharging time and state of charge for keeping the battery bank healthier.

Increasing the Operating Temperature of Nafion Membranes with Addition of Nanocrystalline Oxides for Direct Methanol Fuel Cells

2002 ◽  
Vol 756 ◽  
Author(s):  
Vincenzo Baglio ◽  
Alessandra Di Blasi ◽  
Antonino S. Arico' ◽  
Vincenzo Antonucci ◽  
Pier Luigi Antonucci ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Power Density ◽  
Direct Methanol Fuel Cells ◽  
Maximum Power ◽  
Nafion Membrane ◽  
Membrane Electrode ◽  
Maximum Power Density ◽  
Nafion Membranes ◽  
Direct Methanol ◽  
Methanol Fuel Cells

ABSTRACTComposite Nafion membranes containing various amounts of TiO2 (3%, 5% and 10%) were prepared by using a recast procedure for application in high temperature Direct Methanol Fuel Cells (DMFCs). The electrochemical behaviour was compared to that of a membrane-electrode assembly (MEA) based on a bare recast Nafion membrane. All the MEAs containing the Nafion-titania membranes were able to operate up to 145°C, whereas the assembly equipped with the bare recast Nafion membrane showed the maximum performance at 120°C. A maximum power density of 340 mW cm-2 was achieved at 145°C with the composite membrane in the presence of oxygen feed, whereas the maximum power density with air feed was about 210 mW cm-2.

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