Based on the theoretical analyses, the dynamic and mathematical models of the system were developed. The models were implemented in the ambit of the Matlab/Simulink environment, and an integrated simulation model was ...Based on the theoretical analyses, the dynamic and mathematical models of the system were developed. The models were implemented in the ambit of the Matlab/Simulink environment, and an integrated simulation model was developed. The dynamic performance of the power shift clutch during engagement and disengagement was studied by using this assembly model. The sliding speed, torque transmitted through the clutch, and the rate at which energy is dissipated during the process were determined. Using this model, the calculation during simulation can be simplified. This lays a foundation for the dynamic performance research on the power train with the power shift clutch, and provides a powerful tool for developing an automatic, electronically controlled transmission.展开更多
To improve the vehicular power and acceleration performance and reduce the shift impact, the study of the characteristics on power shift is necessary. Based on the flexible hydraulic unit of hydro-mechanical transmiss...To improve the vehicular power and acceleration performance and reduce the shift impact, the study of the characteristics on power shift is necessary. Based on the flexible hydraulic unit of hydro-mechanical transmission, this paper explores the feasibility of shift without power interruption. With the four models concerning displacement ratio, rotational speed, rotational torque and power at ideal shift point, the characteristics on power shift in different running conditions are analyzed, and the rules of power shift are revealed. The theoretical analysis and test results show that the hydro-mechanical transmission can shift without power interruption in different running conditions. Furthermore, there exists an ideal shift point in theory, at which point the cycle power in hydro-mechanical transmission can＇t be generated, and the impact on the system can be reduced to the minimum. However, if before or after this ideal shift point, a cycle power can be generated.展开更多
Japanese Foreign Minister Seiji Maehara resigned on March 6 after it was reported he had illegally accepted a donation from a South Korean supporter. Three days later, Maehara’s deputy Takeaki Matsumoto was named Ja...Japanese Foreign Minister Seiji Maehara resigned on March 6 after it was reported he had illegally accepted a donation from a South Korean supporter. Three days later, Maehara’s deputy Takeaki Matsumoto was named Japan’s new foreign minister. The Shanghai-based Jiefang Daily published an article by Lian Degui, Deputy Director of the Center for Japanese Studies of the Shanghai Institutes for International Studies, analyzing Japan’s ongoing political strife. The following is an excerpt from the article:展开更多
GO methodology is a success-oriented method for system reliability analysis. There are components with multi-fault modes in repairable systems. It is a problem to use the existing GO method to make reliability analysi...GO methodology is a success-oriented method for system reliability analysis. There are components with multi-fault modes in repairable systems. It is a problem to use the existing GO method to make reliability analysis of such repairable systems. A new GO method for reliability analysis of such repairable systems with multifault modes was presented. Firstly, calculation equations of reliability parameters of operators which were used to describe components with multi-fault modes in reparable systems were derived based on Markov process theory. Then, this new GO method was applied in reliability analysis of a hydraulic transmission oil supply system( HTOSS) of a power-shift steering transmission at low and high speeds. Finally,Compared with fault tree analysis( FTA) and Monte Carlo simulation,the results show that this new GO method is correct and suitable for reliability analysis of repairable system with multi-fault modes.展开更多
A method of multiple outputs least squares support vector regression （LS-SVR） was developed and described in detail, with the radial basis function （RBF） as the kernel function. The method was applied to predict t...A method of multiple outputs least squares support vector regression （LS-SVR） was developed and described in detail, with the radial basis function （RBF） as the kernel function. The method was applied to predict the future state of the power-shift steering transmission （PSST）. A prediction model of PSST was gotten with multiple outputs LS-SVR. The model performance was greatly influenced by the penalty parameter γ and kernel parameter σ2 which were optimized using cross validation method. The training and prediction of the model were done with spectrometric oil analysis data. The predictive and actual values were compared and a fault in the second PSST was found. The research proved that this method had good accuracy in PSST fault prediction, and any possible problem in PSST could be found through a comparative analysis.展开更多
EAST （experimental advanced superconducting tokamak） fast control power supply is a high-capacity single-phase AC/DC/AC inverter power supply, which traces the displacement signal of plasma, and excites coils in a v...EAST （experimental advanced superconducting tokamak） fast control power supply is a high-capacity single-phase AC/DC/AC inverter power supply, which traces the displacement signal of plasma, and excites coils in a vacuum vessel to produce a magnetic field that realizes plasma stabilization. To meet the requirements of a large current and fast response, the multi- ple structure of the carrier phase-shift three-level inverter is presented, which realizes parallelled multi-inverters, raises the equivalent switching frequency of the inverters and improves the per- formance of output waves. In this work the design scheme is analyzed, and the output harmonic characteristic of parallel inverters is studied. The simulation and experimental results confirm that the scheme and control strategy is valid. The power supply system can supply a large current, and has a perfect performance on harmonic features as well as the ability of a fast response.展开更多
The world is facing the third important global power shift.The United States,EU, Japan,Russia,China,and the newly emerging power group are becoming the six big forces in the international center stage,while the former...The world is facing the third important global power shift.The United States,EU, Japan,Russia,China,and the newly emerging power group are becoming the six big forces in the international center stage,while the former three forces and the latter three belong to two groups,waning and waxing respectively.The major shift in the global balance of power is bound to give rise to the transitional multi-polar configuration,which implies a shifting of leadership over the configuration,China and U.S.outweighing other forces,global issues looming large,homogeneity blending with heterogeneity,and a shifting center of world powers.The transitional multi-polar configuration is all about change,upon which China is one of the decisive forces.展开更多
The dynamic math model of shift clutch in engagement process was determined on the basis of hydraulic buffering valve and shift clutch of a power shift steering transmission. The influence of buffering pressure chara...The dynamic math model of shift clutch in engagement process was determined on the basis of hydraulic buffering valve and shift clutch of a power shift steering transmission. The influence of buffering pressure characteristic on shift clutch engagement process was analyzed. The study results could be used to the characteristics match of the shift clutch with the hydraulic system of the high speed tracked vehicle power shift steering transmission and the performance prediction.展开更多
双有源桥式(dual active bridge,DAB)变流器目前广泛应用于直流微网、燃料电池、电动汽车等领域,其具有功率密度高、能量双向流动、电气隔离、易于实现软开关等优点,但目前在轨道交通变流器领域应用较少。针对轨道交通领域高压大功率、...双有源桥式(dual active bridge,DAB)变流器目前广泛应用于直流微网、燃料电池、电动汽车等领域,其具有功率密度高、能量双向流动、电气隔离、易于实现软开关等优点,但目前在轨道交通变流器领域应用较少。针对轨道交通领域高压大功率、模块化应用场景的特殊需求,文章创新性地设计了一种基于单移相控制的ISOP-DAB(input-series output-parallel,ISOP)双向储能变流器,将其应用于某型出口机车项目,能够实现动力电池与牵引直流母线之间的能量双向流动,并针对性地解决了ISOP-DAB的输入侧均压与输出侧均流的问题,系统性地分析了在此控制策略下,双向储能变流器的基本工作原理和功率传输特性。通过引入动态解耦控制算法,实现了输出电压稳定与模块均衡的双目标协同控制。最后,通过MATLAB搭建仿真模型进行仿真试验,并且完成了包含充放电切换、动态负载等实物整柜型式试验,验证了该控制策略的有效性与可行性,为轨道交通领域双向储能变流器的模块化设计提供了理论依据和工程实践参考。展开更多
文摘Based on the theoretical analyses, the dynamic and mathematical models of the system were developed. The models were implemented in the ambit of the Matlab/Simulink environment, and an integrated simulation model was developed. The dynamic performance of the power shift clutch during engagement and disengagement was studied by using this assembly model. The sliding speed, torque transmitted through the clutch, and the rate at which energy is dissipated during the process were determined. Using this model, the calculation during simulation can be simplified. This lays a foundation for the dynamic performance research on the power train with the power shift clutch, and provides a powerful tool for developing an automatic, electronically controlled transmission.
基金supported by National Key Laboratory of Vehicular Transmission Foundation of China (Grant No. 9140C3402050702)
文摘To improve the vehicular power and acceleration performance and reduce the shift impact, the study of the characteristics on power shift is necessary. Based on the flexible hydraulic unit of hydro-mechanical transmission, this paper explores the feasibility of shift without power interruption. With the four models concerning displacement ratio, rotational speed, rotational torque and power at ideal shift point, the characteristics on power shift in different running conditions are analyzed, and the rules of power shift are revealed. The theoretical analysis and test results show that the hydro-mechanical transmission can shift without power interruption in different running conditions. Furthermore, there exists an ideal shift point in theory, at which point the cycle power in hydro-mechanical transmission can＇t be generated, and the impact on the system can be reduced to the minimum. However, if before or after this ideal shift point, a cycle power can be generated.
文摘Japanese Foreign Minister Seiji Maehara resigned on March 6 after it was reported he had illegally accepted a donation from a South Korean supporter. Three days later, Maehara’s deputy Takeaki Matsumoto was named Japan’s new foreign minister. The Shanghai-based Jiefang Daily published an article by Lian Degui, Deputy Director of the Center for Japanese Studies of the Shanghai Institutes for International Studies, analyzing Japan’s ongoing political strife. The following is an excerpt from the article:
基金Technical Basis Projects of China's MIIT(No.2012090003)
文摘GO methodology is a success-oriented method for system reliability analysis. There are components with multi-fault modes in repairable systems. It is a problem to use the existing GO method to make reliability analysis of such repairable systems. A new GO method for reliability analysis of such repairable systems with multifault modes was presented. Firstly, calculation equations of reliability parameters of operators which were used to describe components with multi-fault modes in reparable systems were derived based on Markov process theory. Then, this new GO method was applied in reliability analysis of a hydraulic transmission oil supply system( HTOSS) of a power-shift steering transmission at low and high speeds. Finally,Compared with fault tree analysis( FTA) and Monte Carlo simulation,the results show that this new GO method is correct and suitable for reliability analysis of repairable system with multi-fault modes.
基金Supported by the Ministerial Level Advanced Research Foundation(3031030)the"111"Project(B08043)
文摘A method of multiple outputs least squares support vector regression （LS-SVR） was developed and described in detail, with the radial basis function （RBF） as the kernel function. The method was applied to predict the future state of the power-shift steering transmission （PSST）. A prediction model of PSST was gotten with multiple outputs LS-SVR. The model performance was greatly influenced by the penalty parameter γ and kernel parameter σ2 which were optimized using cross validation method. The training and prediction of the model were done with spectrometric oil analysis data. The predictive and actual values were compared and a fault in the second PSST was found. The research proved that this method had good accuracy in PSST fault prediction, and any possible problem in PSST could be found through a comparative analysis.
基金supported by Key Project of National Ninth Five-Year Research Program of China[(1998)1303]
文摘EAST （experimental advanced superconducting tokamak） fast control power supply is a high-capacity single-phase AC/DC/AC inverter power supply, which traces the displacement signal of plasma, and excites coils in a vacuum vessel to produce a magnetic field that realizes plasma stabilization. To meet the requirements of a large current and fast response, the multi- ple structure of the carrier phase-shift three-level inverter is presented, which realizes parallelled multi-inverters, raises the equivalent switching frequency of the inverters and improves the per- formance of output waves. In this work the design scheme is analyzed, and the output harmonic characteristic of parallel inverters is studied. The simulation and experimental results confirm that the scheme and control strategy is valid. The power supply system can supply a large current, and has a perfect performance on harmonic features as well as the ability of a fast response.
文摘The world is facing the third important global power shift.The United States,EU, Japan,Russia,China,and the newly emerging power group are becoming the six big forces in the international center stage,while the former three forces and the latter three belong to two groups,waning and waxing respectively.The major shift in the global balance of power is bound to give rise to the transitional multi-polar configuration,which implies a shifting of leadership over the configuration,China and U.S.outweighing other forces,global issues looming large,homogeneity blending with heterogeneity,and a shifting center of world powers.The transitional multi-polar configuration is all about change,upon which China is one of the decisive forces.
文摘The dynamic math model of shift clutch in engagement process was determined on the basis of hydraulic buffering valve and shift clutch of a power shift steering transmission. The influence of buffering pressure characteristic on shift clutch engagement process was analyzed. The study results could be used to the characteristics match of the shift clutch with the hydraulic system of the high speed tracked vehicle power shift steering transmission and the performance prediction.
文摘双有源桥式(dual active bridge,DAB)变流器目前广泛应用于直流微网、燃料电池、电动汽车等领域,其具有功率密度高、能量双向流动、电气隔离、易于实现软开关等优点,但目前在轨道交通变流器领域应用较少。针对轨道交通领域高压大功率、模块化应用场景的特殊需求,文章创新性地设计了一种基于单移相控制的ISOP-DAB(input-series output-parallel,ISOP)双向储能变流器,将其应用于某型出口机车项目,能够实现动力电池与牵引直流母线之间的能量双向流动,并针对性地解决了ISOP-DAB的输入侧均压与输出侧均流的问题,系统性地分析了在此控制策略下,双向储能变流器的基本工作原理和功率传输特性。通过引入动态解耦控制算法,实现了输出电压稳定与模块均衡的双目标协同控制。最后,通过MATLAB搭建仿真模型进行仿真试验,并且完成了包含充放电切换、动态负载等实物整柜型式试验,验证了该控制策略的有效性与可行性,为轨道交通领域双向储能变流器的模块化设计提供了理论依据和工程实践参考。
