A large-scale compressor set of a 2 kW helium cryoplant, as one of the subsystems of EAST （the experimental advanced superconducting tokamak）, is arranged in a two-stage seriesparallel structure. A fully automatic c...A large-scale compressor set of a 2 kW helium cryoplant, as one of the subsystems of EAST （the experimental advanced superconducting tokamak）, is arranged in a two-stage seriesparallel structure. A fully automatic control system used to handle the compressors＇ on/off/ scheduling and the pressures＇ adjustment was developed. To reduce the long time lag and the uncertainty with the energy slide valves effectively, expert rules in combination with proportional- integral-derivative （PID） algorithms were applied nisms were built up to reinforce its stability and to the EAST operations and is operated stably. system, such as the big overshoot of pressure and Safety protection and status analysis mecha- robustness. The new system has been applied The problems in the previous semi-automatic complexity of the operations, were solved.展开更多
The dynamic research of aircraft environmental control system (ECS) is an important step in the advanced ECS design process. Based on the thermodynamics theory, mathematical models for the dynamic performance simulati...The dynamic research of aircraft environmental control system (ECS) is an important step in the advanced ECS design process. Based on the thermodynamics theory, mathematical models for the dynamic performance simulating of aircraft ECS were set up and an ECS simulation toolbox (ECS_1.0) was created with MATLAB language. It consists of main component modules (ducts, valves, heat exchangers, compressor, turbine, etc.). An aircraft environmental control system computer model was developed to assist engineers with the design and development of ECS dynamic optimization. An example simulating an existing ECS was given which shows the satisfactory effects.展开更多
To prevent the oxygen starvation and improve the system output performance, an adaptive inverse control （AIC） strategy is developed to regulate the air supply flow of a proton exchange membrane fuel cell （PEMFC） s...To prevent the oxygen starvation and improve the system output performance, an adaptive inverse control （AIC） strategy is developed to regulate the air supply flow of a proton exchange membrane fuel cell （PEMFC） system in this paper. The PEMFC stack and the air supply system including a compressor and a supply manifold are modeled for the purpose of performance analysis and controller design. A recurrent fuzzy neural network （RFNN） is utilized to identify the inverse model of the controlled system and generates a suitable control input during the abrupt step change of external disturbances. Compared with the PI controller, numerical simulations are performed to validate the effectiveness and advantages of the proposed AIC strategy.展开更多
A numerical methodology for investigating compressor instabilities in a multistage environment is presented. The method is based on a stage-by-stage dynamic compression model and considers air compressibility explicit...A numerical methodology for investigating compressor instabilities in a multistage environment is presented. The method is based on a stage-by-stage dynamic compression model and considers air compressibility explicitly throughout the compressor. It involves discretizing the compression system into distinct elements and a use of the local elemental characteristic of mean performance. The models are presented in both nonlinear and linearized forms. The linearised form permits well surge condition prediction for multistage axial compressors, while the non-linear form is able to investigate the growth of local flow disturbances, and helps to develop practical control strategy. Validations were carried out using the data from several aircraft engine compressors. A good experiment-model consistency is achieved.展开更多
基金supported by National Meg-science Engineering Project of the Chinese Government,[1998]1303
文摘A large-scale compressor set of a 2 kW helium cryoplant, as one of the subsystems of EAST （the experimental advanced superconducting tokamak）, is arranged in a two-stage seriesparallel structure. A fully automatic control system used to handle the compressors＇ on/off/ scheduling and the pressures＇ adjustment was developed. To reduce the long time lag and the uncertainty with the energy slide valves effectively, expert rules in combination with proportional- integral-derivative （PID） algorithms were applied nisms were built up to reinforce its stability and to the EAST operations and is operated stably. system, such as the big overshoot of pressure and Safety protection and status analysis mecha- robustness. The new system has been applied The problems in the previous semi-automatic complexity of the operations, were solved.
文摘The dynamic research of aircraft environmental control system (ECS) is an important step in the advanced ECS design process. Based on the thermodynamics theory, mathematical models for the dynamic performance simulating of aircraft ECS were set up and an ECS simulation toolbox (ECS_1.0) was created with MATLAB language. It consists of main component modules (ducts, valves, heat exchangers, compressor, turbine, etc.). An aircraft environmental control system computer model was developed to assist engineers with the design and development of ECS dynamic optimization. An example simulating an existing ECS was given which shows the satisfactory effects.
基金Project supported by the National Natural Science Foundation of China (Grant No.20576071)the Natural Science Foundation of Shanghai Municipality (Grant No.08ZR1409800)
文摘To prevent the oxygen starvation and improve the system output performance, an adaptive inverse control （AIC） strategy is developed to regulate the air supply flow of a proton exchange membrane fuel cell （PEMFC） system in this paper. The PEMFC stack and the air supply system including a compressor and a supply manifold are modeled for the purpose of performance analysis and controller design. A recurrent fuzzy neural network （RFNN） is utilized to identify the inverse model of the controlled system and generates a suitable control input during the abrupt step change of external disturbances. Compared with the PI controller, numerical simulations are performed to validate the effectiveness and advantages of the proposed AIC strategy.
基金This project is supported by National Natural Science Foundation of China (No.50146014) National Natural Science Foundation of Xi'an Jiaotong University, China (No.573023).
文摘A numerical methodology for investigating compressor instabilities in a multistage environment is presented. The method is based on a stage-by-stage dynamic compression model and considers air compressibility explicitly throughout the compressor. It involves discretizing the compression system into distinct elements and a use of the local elemental characteristic of mean performance. The models are presented in both nonlinear and linearized forms. The linearised form permits well surge condition prediction for multistage axial compressors, while the non-linear form is able to investigate the growth of local flow disturbances, and helps to develop practical control strategy. Validations were carried out using the data from several aircraft engine compressors. A good experiment-model consistency is achieved.
