The aim of this paper is the evaluation of the performance of a low pressure PEM （proton exchange membrane） fuel cell stack to step load changes, which are characteristic of standalone fuel cell system applications....The aim of this paper is the evaluation of the performance of a low pressure PEM （proton exchange membrane） fuel cell stack to step load changes, which are characteristic of standalone fuel cell system applications. The goal is a better understanding of the electrical behavior of the FC （fuel cell）, as a result of the electrochemical processes, via the cell＇s voltage characteristic during transient response. While changing the load, the performance of significant parameters affected such as temperature, pressure, purge status etc. are registered and evaluated. The analysis and experiment are based on a low pressure 1.2 kW PEM fuel cell stack （NEXAS power module）. Then, the experiment is simulated using Matlab/Simulink tools, while PCU （power conditioning units） are added in order to control power flow for enhanced performance. Finally, both operational and simulation data are compared to each other showing that simple PCUs applications can improve system＇s efficiency.展开更多
To observe the inner operating process of distance protection,a Matlab/Simulink based dynamic simulation system for microprocessor-based distance protection is designed in this paper.As a modularized design,the simula...To observe the inner operating process of distance protection,a Matlab/Simulink based dynamic simulation system for microprocessor-based distance protection is designed in this paper.As a modularized design,the simulation system is composed of several modules such as fault transient calculation,startup,Fourier algorithm,phase selection,impedance computing and impedance comparison etc.Some typical simulation cases,which focus on the main factors affecting distance relay's operation,have been simulated with the system.Simulation results show that the system is able to demonstrate the dynamic behaviors of distance protection under different operating conditions.展开更多
Screening is an important process in mineral industry. In this paper, a study has been made to simulate the screening process based on a high-performance MATLAB/Simulink software, with an example of simulating the sie...Screening is an important process in mineral industry. In this paper, a study has been made to simulate the screening process based on a high-performance MATLAB/Simulink software, with an example of simulating the sieving process of a vibrating screen. A simulation model of the sieving process with a vibrating screen （SMSPVS） was proposed, using correlative mathematical models and Simulink blocks. The results show that the simulation data was very close to the actual data, The minimum errors of size distribution of oversize and undersize are 0.65% and 0.20%, resoectivelv. The sieving orocess can be accurately simulated by the SMSPVS.展开更多
High speed and ultra-high capacity optical communications have emerged as the essential techniques for backbone global information transmission networks. As the bit rate of the transmission system gets higher and high...High speed and ultra-high capacity optical communications have emerged as the essential techniques for backbone global information transmission networks. As the bit rate of the transmission system gets higher and higher 40 Gb/s to 100 Gb/s the modeling of proposed modulation techniques is very important so as to avoid costly practical demonstration. The search for a universal modeling platform for such systems is urgent. Matlab Simulink has become the universal mathematical and modeling tools in most universities and re-search laboratories around the world. This paper thus describes the modeling techniques for advanced photonic transmission systems and Simulink is proven to be very effective platform for development of photonic communications systems due its comprehensive blocksets. The simulation is based mainly on the physical phenomena and understanding of its concepts of communications and photonics. Simulink models are given as examples of various sub-systems of the photonic transmission systems. Some simulated trans-mission performances are demonstrated as examples of final results obtained from Simulink models of the transmission systems.展开更多
Based on MATLAB/SIMULINK, the paper has proposed cost risk simulation models separately in accor-dance with the circumstances of correlation and independence between the influential factors of cost risk. The mean,vari...Based on MATLAB/SIMULINK, the paper has proposed cost risk simulation models separately in accor-dance with the circumstances of correlation and independence between the influential factors of cost risk. The mean,variance and the risk level under the above-mentioned two circumstances have also been compared with a case study.Also the sensitivity analysis of cost risk has been probed into. The result indicates that the model which takes into ac-count correlation is more objective, and the model which ignores the circumstance of correlation normally underes-timates the risk level of project cost.展开更多
文摘The aim of this paper is the evaluation of the performance of a low pressure PEM （proton exchange membrane） fuel cell stack to step load changes, which are characteristic of standalone fuel cell system applications. The goal is a better understanding of the electrical behavior of the FC （fuel cell）, as a result of the electrochemical processes, via the cell＇s voltage characteristic during transient response. While changing the load, the performance of significant parameters affected such as temperature, pressure, purge status etc. are registered and evaluated. The analysis and experiment are based on a low pressure 1.2 kW PEM fuel cell stack （NEXAS power module）. Then, the experiment is simulated using Matlab/Simulink tools, while PCU （power conditioning units） are added in order to control power flow for enhanced performance. Finally, both operational and simulation data are compared to each other showing that simple PCUs applications can improve system＇s efficiency.
基金National Natural Science Foundation of China(No.50777040)
文摘To observe the inner operating process of distance protection,a Matlab/Simulink based dynamic simulation system for microprocessor-based distance protection is designed in this paper.As a modularized design,the simulation system is composed of several modules such as fault transient calculation,startup,Fourier algorithm,phase selection,impedance computing and impedance comparison etc.Some typical simulation cases,which focus on the main factors affecting distance relay's operation,have been simulated with the system.Simulation results show that the system is able to demonstrate the dynamic behaviors of distance protection under different operating conditions.
文摘Screening is an important process in mineral industry. In this paper, a study has been made to simulate the screening process based on a high-performance MATLAB/Simulink software, with an example of simulating the sieving process of a vibrating screen. A simulation model of the sieving process with a vibrating screen （SMSPVS） was proposed, using correlative mathematical models and Simulink blocks. The results show that the simulation data was very close to the actual data, The minimum errors of size distribution of oversize and undersize are 0.65% and 0.20%, resoectivelv. The sieving orocess can be accurately simulated by the SMSPVS.
文摘High speed and ultra-high capacity optical communications have emerged as the essential techniques for backbone global information transmission networks. As the bit rate of the transmission system gets higher and higher 40 Gb/s to 100 Gb/s the modeling of proposed modulation techniques is very important so as to avoid costly practical demonstration. The search for a universal modeling platform for such systems is urgent. Matlab Simulink has become the universal mathematical and modeling tools in most universities and re-search laboratories around the world. This paper thus describes the modeling techniques for advanced photonic transmission systems and Simulink is proven to be very effective platform for development of photonic communications systems due its comprehensive blocksets. The simulation is based mainly on the physical phenomena and understanding of its concepts of communications and photonics. Simulink models are given as examples of various sub-systems of the photonic transmission systems. Some simulated trans-mission performances are demonstrated as examples of final results obtained from Simulink models of the transmission systems.
文摘Based on MATLAB/SIMULINK, the paper has proposed cost risk simulation models separately in accor-dance with the circumstances of correlation and independence between the influential factors of cost risk. The mean,variance and the risk level under the above-mentioned two circumstances have also been compared with a case study.Also the sensitivity analysis of cost risk has been probed into. The result indicates that the model which takes into ac-count correlation is more objective, and the model which ignores the circumstance of correlation normally underes-timates the risk level of project cost.
