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Temperature Control for a Polymer Electrolyte Membrane Fuel Cell by Using Fuzzy Rule
Ya-Xiong Wang,Fei-Fei Qin,Kai Ou,Young-Bae Kim IEEE 2016 IEEE transactions on energy conversion Vol.31 No.2
<P>Temperature control for a polymer electrolyte membrane fuel cell (PEMFC) is important in improving power efficiency and increasing fuel cell lifetime. If the temperature of the cell is too low, then the electrochemical reaction response becomes slow, thereby preventing evaporations of liquid water in the membrane. As a result, cell performance is decreased. However, too high temperature leads to waste in catalyst and heat because of excessive chemical reactions and to liquid water evaporation, which decreases proton conductivity. This study develops an electrochemical dynamical model and a thermal model of a PEMFC using MATLAB/Simulink for simulation. Fuzzy control rules are also built to regulate the temperature of a PEMFC. The fuzzy inputs include temperature error, its derivative, and external load current. The cooling fan speed is chosen as an output variable to regulate the temperature of a fuzzy control because the fuel cell utilizes the air cooling method. After confirming that the designed fuzzy rules are effective for controlling cell temperature, a real experimental device is built using an H-100 fuel cell and a cooling fan to verify the effectiveness of the proposed method.</P>
Ya-Xiong Wang,Fei-Fei Qin,Kai Ou,Young-Bae Kim 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6
DC/DC converters with hybrid proton exchange membrane (PEM) fuel cell and battery power sources are designed and implemented using sliding mode control (SMC). The converters are typically comprised by unidirectional boost converter and bidirectional converter which are used for regulating the bus voltage and managing power distribution. SMC is selected to control the converters since it can cope with the high non-linear characteristic of the coupled system as well as ensure the stability. The hybrid power control system is constructed in MATLAB/Simulink platform. A comparative approach based on conventional proportional-integral (PI) control is developed to compare the control performance with SMC. The experimental validation is carried out with National Instruments (NI) LabVIEW-based hybrid PEMFC/battery supplied DC/DC converters system prototype.
Wang, Ya-Xiong,Ou, Kai,Kim, Young-Bae Pergamon 2017 RENEWABLE ENERGY Vol.111 No.-
<P><B>Abstract</B></P> <P>Polymer electrolyte membrane fuel cell hybridized with lithium-ion battery possesses significant advantages, including the combination of large energy carrier feature with high power density to provide a power source for large fluctuated areas such as a vehicle or a construction equipment. A hybrid system obviously requires a suitable power management means to distribute each power source optimally and ensure safe and efficient power system operation. This study investigates hybrid system power distribution and the protection of power sources, namely, PEMFC and/or LIB, to extend their lifetimes under the condition of external load variations. Power distribution with the purpose of power source protection is developed to balance the power and stabilize the DC-link voltage with the developed hybrid model. In particular, two new power splitting methods are proposed: coordinated current–voltage control and dual-voltage control. Moreover, these two control schemes are selected depending on the threshold load current. The threshold load current is decided by fuzzy logic rules to prevent power shortage in PEMFC by current control for higher load and to regulate LIB's state-of-charge for lower load. To validate the proposed power management approach, experimental tests are conducted on a hybrid PEMFC/LIB power system prototype.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hybrid models including PEMFC, LIB, and dc converters are developed. </LI> <LI> Power source protection is designed and proved through simulation and experiment. </LI> <LI> Fuel cell protection from sudden power requirement is achieved using current-voltage control scheme. </LI> <LI> Battery protection from overcharge is prohibited using dual voltage control scheme. </LI> <LI> Current-voltage control method and dual voltage control method is selected through fuzzy logic rules. </LI> </UL> </P>
Wei Jin,Chamin Geng,Ya’ou Wang,Huan Ma,Yunshan Dong,Fengqi Si 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.4
Separated overfire air (SOFA) is typically employed in coal-fired boilers with air staged technology to sustain lower NOX emission, and SOFA nozzle angles are crucial adjustment parameters. In this work, the combined effects of SOFA yaw and tilt angles on combustion characteristics were numerically investigated for a 1,000MW dual circle tangentially coal-fired boiler. Numerical results show that the forward increase of the SOFA yaw angle from 0o brings about the enlarged SOFA tangential circle and the gradual appearance of bimodal high-temperature zones at furnace exit. With further tuning SOFA tilt angles vertically, the bimodal high-temperature zones would separate to the two halves of the furnace, inducing a more severe deviation of gas temperature. Besides, the gas residual rotating momentum is strengthened as SOFA yaw angles forward increase, resulting in the enhancement of traction effect in the upper furnace as well as the rise of flame. However, the gas velocity deviation is somewhat eliminated as SOFA rotates reversely. No matter that the SOFA yaw angle increases forward or reversely, the coal burnout would deteriorate with the overly enlarged SOFA tangential circles. Tuning SOFA yaw and tilt angles, respectively, at 5o and 0o can simultaneously guarantee lower CO and NOX emissions.