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 transmissio...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
为解决传统双有源桥(dual active bridge,DAB)变换器在宽输入电压工况下无法同时实现零回流功率和全局软开关的问题,提出了一种基于LCL-T谐振型DAB变换器的改进三重移相(improved triple-phase-shift,ITPS)调制策略。首先,对LCL-T谐振型...为解决传统双有源桥(dual active bridge,DAB)变换器在宽输入电压工况下无法同时实现零回流功率和全局软开关的问题,提出了一种基于LCL-T谐振型DAB变换器的改进三重移相(improved triple-phase-shift,ITPS)调制策略。首先,对LCL-T谐振型DAB变换器的功率传输特性和软开关特性进行分析,推导出不同电压转换比下无回流功率的控制量表达式。然后,利用LCL谐振网络的对称特性和考虑开关管寄生电容影响下的零电压开关(zero voltage switching,ZVS)约束条件,推导出全工况连续、形式统一、计算量小的ITPS调制控制量表达式,并对调制轨迹进行优化。最后,设计了一台1 kW的实验样机进行调制策略有效性的验证。实验结果表明,与传统调制策略相比,ITPS调制策略具有较宽输入电压范围、无回流功率及全局软开关的优势。展开更多
大规模分布式新能源接入导致新型配电系统面临“节点-网络”双重灵活性不足风险,使得规划配置智能混合储能软开关(hybrid energy storage system-soft open point,HESSSOP),实现节点型与网络型异质灵活资源协同控制,成为提升节点灵活调...大规模分布式新能源接入导致新型配电系统面临“节点-网络”双重灵活性不足风险,使得规划配置智能混合储能软开关(hybrid energy storage system-soft open point,HESSSOP),实现节点型与网络型异质灵活资源协同控制,成为提升节点灵活调节支撑和网络传输安全裕度的重要技术手段。对此,建立面向HESS-SOP融入支撑“节点-网络”双重灵活性的新型配电系统协同规划-运行模型。首先,研究SOP引入HESS组成HESS-SOP的拓扑结构和联合调节特性;然后,引入转移分布因子以线路为视角建立含HESSSOP的新型配电系统灵活性供需平衡模型,解析“节点-网络”灵活性供需平衡机理,并建立“节点-网络”双维度灵活性指标;其次,采用有功潮流灵敏度法与希尔伯特-黄变换法对HESS-SOP分别进行选址与初始参数配置,并建立考虑HESS-SOP“节点-网络”双重灵活性调控潜力的规划-运行联合优化模型,并采用混合算法进行求解;最后,基于改进的IEEE33节点系统开展算例分析。结果表明:所提出的灵活性指标能准确量化评估系统“节点-网络”双维度灵活性,所建立的考虑HESS-SOP灵活性调控潜力的规划-运行联合优化模型能有效提高配电系统运行的经济性与灵活性。展开更多
Utilizing translation operators we get the powers sums on arithmetic progressions and the Bernoulli polynomials of order munder the form of differential operators acting on monomials. It follows that (d/dn-d/dz) appli...Utilizing translation operators we get the powers sums on arithmetic progressions and the Bernoulli polynomials of order munder the form of differential operators acting on monomials. It follows that (d/dn-d/dz) applied on a power sum has a meaning and is exactly equal to the Bernoulli polynomial of the same order. From this new property we get the formula giving powers sums in term of sums of successive derivatives of Bernoulli polynomial multiplied withprimitives of the same order of n. Then by changing the two arguments z,n into Z=z(z-1), λ where λ designed the 1st order power sums and proving that Bernoulli polynomials of odd order vanish for arguments equal to 0, 1/2, 1, we obtain easily the Faulhaber formula for powers sums in term of polynomials in λ having coefficients depending on Z. These coefficients are found to be derivatives of odd powers sums on integers expressed in Z. By the way we obtain the link between Faulhaber formulae for powers sums on integers and on arithmetic progressions. To complete the work we propose tables for calculating in easiest manners possibly the Bernoulli numbers, the Bernoulli polynomials, the powers sums and the Faulhaber formula for powers sums.展开更多
The highpower pulsed power supply system for the magnetic field of the HL-2A Tokamak is described in this paper. The total output power of its eight magnetic field power supply units of nearly 250 MW. Their highest DC...The highpower pulsed power supply system for the magnetic field of the HL-2A Tokamak is described in this paper. The total output power of its eight magnetic field power supply units of nearly 250 MW. Their highest DC output voltage and current are 3510 V and 45 kA, respectively. All the units are operated in a pulsed mode. The pulse duration is 5 s, and the cyclic period is 15 min. The power supply system consists mainly of pulsed flywheel motor generators, rectifying transformers, thyristor converters, diode rectifiers and switches. The system incorporates many key technologies-supply equalization with two generators and four diode bridges, constant-angle phase triggers with a wide frequency range, current equalization, a status detector for the high current 6-phase converter, and advanced monitoring based on a programmable logic computer and engineering parameter measurement. The experimental results show that the performance of the power supply system satisfies the requirements of HL-2A experiments very well.展开更多
This paper provides a new approach to spatial spectral estimation, called eigenvalue shift superresolution algorithm. This method avoids the inverse covariance matrix. It can be applied to the processing of data recei...This paper provides a new approach to spatial spectral estimation, called eigenvalue shift superresolution algorithm. This method avoids the inverse covariance matrix. It can be applied to the processing of data received by spatially distributed array of sensors.展开更多
Dynamic tidal power is a new way of capturing tidal energy by building a water head using a dike perpendicular to the coast. This study explored the hydrodynamic mechanism of the water head across an intended dynamic ...Dynamic tidal power is a new way of capturing tidal energy by building a water head using a dike perpendicular to the coast. This study explored the hydrodynamic mechanism of the water head across an intended dynamic tidal power dike system using the Delft3 D-FLOW software module. The propagating wave was simulated in a rectangular domain with a horizontal sea bottom at a 30-m depth. A significant water head was created across the dike by blocking the water. The water head increased with increasing dike length and increasing undisturbed tidal current acceleration. The maximum water head for the dike with a length of 50 km, located 900 km from the western boundary, was 2.15 m,which exceeded the undisturbed tidal range. The time series of the water head behaved in a manner identical to the undisturbed tidal current acceleration. The distribution of the water head over the dike assumed an elliptical shape. A parasitic wave was generated at the attachment and scattered outward. The phase lag across the dike did not behave as a linear function of the detour distance.展开更多
An extraneous harmonics detection scheme is introduced, based on the frequency shift technique. The main principle is described; practical operation scheme is il-lustrated; both related microcomputer system circuit an...An extraneous harmonics detection scheme is introduced, based on the frequency shift technique. The main principle is described; practical operation scheme is il-lustrated; both related microcomputer system circuit and its software designs are alsobriefly described. Finally, the scheme is validated by the experiment results.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.
文摘为解决传统双有源桥(dual active bridge,DAB)变换器在宽输入电压工况下无法同时实现零回流功率和全局软开关的问题,提出了一种基于LCL-T谐振型DAB变换器的改进三重移相(improved triple-phase-shift,ITPS)调制策略。首先,对LCL-T谐振型DAB变换器的功率传输特性和软开关特性进行分析,推导出不同电压转换比下无回流功率的控制量表达式。然后,利用LCL谐振网络的对称特性和考虑开关管寄生电容影响下的零电压开关(zero voltage switching,ZVS)约束条件,推导出全工况连续、形式统一、计算量小的ITPS调制控制量表达式,并对调制轨迹进行优化。最后,设计了一台1 kW的实验样机进行调制策略有效性的验证。实验结果表明,与传统调制策略相比,ITPS调制策略具有较宽输入电压范围、无回流功率及全局软开关的优势。
文摘大规模分布式新能源接入导致新型配电系统面临“节点-网络”双重灵活性不足风险,使得规划配置智能混合储能软开关(hybrid energy storage system-soft open point,HESSSOP),实现节点型与网络型异质灵活资源协同控制,成为提升节点灵活调节支撑和网络传输安全裕度的重要技术手段。对此,建立面向HESS-SOP融入支撑“节点-网络”双重灵活性的新型配电系统协同规划-运行模型。首先,研究SOP引入HESS组成HESS-SOP的拓扑结构和联合调节特性;然后,引入转移分布因子以线路为视角建立含HESSSOP的新型配电系统灵活性供需平衡模型,解析“节点-网络”灵活性供需平衡机理,并建立“节点-网络”双维度灵活性指标;其次,采用有功潮流灵敏度法与希尔伯特-黄变换法对HESS-SOP分别进行选址与初始参数配置,并建立考虑HESS-SOP“节点-网络”双重灵活性调控潜力的规划-运行联合优化模型,并采用混合算法进行求解;最后,基于改进的IEEE33节点系统开展算例分析。结果表明:所提出的灵活性指标能准确量化评估系统“节点-网络”双维度灵活性,所建立的考虑HESS-SOP灵活性调控潜力的规划-运行联合优化模型能有效提高配电系统运行的经济性与灵活性。
文摘Utilizing translation operators we get the powers sums on arithmetic progressions and the Bernoulli polynomials of order munder the form of differential operators acting on monomials. It follows that (d/dn-d/dz) applied on a power sum has a meaning and is exactly equal to the Bernoulli polynomial of the same order. From this new property we get the formula giving powers sums in term of sums of successive derivatives of Bernoulli polynomial multiplied withprimitives of the same order of n. Then by changing the two arguments z,n into Z=z(z-1), λ where λ designed the 1st order power sums and proving that Bernoulli polynomials of odd order vanish for arguments equal to 0, 1/2, 1, we obtain easily the Faulhaber formula for powers sums in term of polynomials in λ having coefficients depending on Z. These coefficients are found to be derivatives of odd powers sums on integers expressed in Z. By the way we obtain the link between Faulhaber formulae for powers sums on integers and on arithmetic progressions. To complete the work we propose tables for calculating in easiest manners possibly the Bernoulli numbers, the Bernoulli polynomials, the powers sums and the Faulhaber formula for powers sums.
文摘The highpower pulsed power supply system for the magnetic field of the HL-2A Tokamak is described in this paper. The total output power of its eight magnetic field power supply units of nearly 250 MW. Their highest DC output voltage and current are 3510 V and 45 kA, respectively. All the units are operated in a pulsed mode. The pulse duration is 5 s, and the cyclic period is 15 min. The power supply system consists mainly of pulsed flywheel motor generators, rectifying transformers, thyristor converters, diode rectifiers and switches. The system incorporates many key technologies-supply equalization with two generators and four diode bridges, constant-angle phase triggers with a wide frequency range, current equalization, a status detector for the high current 6-phase converter, and advanced monitoring based on a programmable logic computer and engineering parameter measurement. The experimental results show that the performance of the power supply system satisfies the requirements of HL-2A experiments very well.
文摘This paper provides a new approach to spatial spectral estimation, called eigenvalue shift superresolution algorithm. This method avoids the inverse covariance matrix. It can be applied to the processing of data received by spatially distributed array of sensors.
基金supported by the National Key R&D Program of China(Grant No.2017YFC1404200)the National Natural Science Foundation of China(Grants No.51520105014 and 51509168)the National Special Funds for Basic Scientific Research for Research Institutes(Grant No.Y218008)
文摘Dynamic tidal power is a new way of capturing tidal energy by building a water head using a dike perpendicular to the coast. This study explored the hydrodynamic mechanism of the water head across an intended dynamic tidal power dike system using the Delft3 D-FLOW software module. The propagating wave was simulated in a rectangular domain with a horizontal sea bottom at a 30-m depth. A significant water head was created across the dike by blocking the water. The water head increased with increasing dike length and increasing undisturbed tidal current acceleration. The maximum water head for the dike with a length of 50 km, located 900 km from the western boundary, was 2.15 m,which exceeded the undisturbed tidal range. The time series of the water head behaved in a manner identical to the undisturbed tidal current acceleration. The distribution of the water head over the dike assumed an elliptical shape. A parasitic wave was generated at the attachment and scattered outward. The phase lag across the dike did not behave as a linear function of the detour distance.
文摘An extraneous harmonics detection scheme is introduced, based on the frequency shift technique. The main principle is described; practical operation scheme is il-lustrated; both related microcomputer system circuit and its software designs are alsobriefly described. Finally, the scheme is validated by the experiment results.
