为了降低降压变压器的安装空间及磁饱和等因素给铁路功率调节器(railway static power conditioner,RPC)工程应用及治理效果带来的不利影响,模块化多电平换流器的铁路功率调节器(railway static power conditioner of modular multileve...为了降低降压变压器的安装空间及磁饱和等因素给铁路功率调节器(railway static power conditioner,RPC)工程应用及治理效果带来的不利影响,模块化多电平换流器的铁路功率调节器(railway static power conditioner of modular multilevel converter,MMC-RPC)成为研究热点。但现有的MMC-RPC控制策略没有考虑电力机车实际负荷功率及电流波动特性对MMC各子模块电容电压影响,使其电容电压波动较大。为此,根据电力机车功率及负荷运行特性,采用混合PWM调制策略,既能满足开关损耗低的要求,又能适应电力机车动态运行特性下MMC-RPC各子模块电容均压波动范围。最后,通过仿真和实验结果验证了MMC-RPC输出性能相对传统二电平RPC的优越性,采用的混合PWM调制策略能够使得MMC-RPC适应电力机车实际负荷功率及电流波动特性,各子模块电容均压波动幅值均有效控制在±5%范围内。展开更多
The simulation model of the E car HS2000 including the permanent magnetic direct current motor with the augment magnet winding is constructed based on tests in order to simulate the synthetic performance of the elec...The simulation model of the E car HS2000 including the permanent magnetic direct current motor with the augment magnet winding is constructed based on tests in order to simulate the synthetic performance of the electric car. The performance of E car HS2000 is analyzed by means of modeling and programming according to data acquired during tests. The simulation results show that the performance of E car HS2000 is successfully predicted and the model and the corresponding simulation software are feasible for simulating E cars. They can be used as effective tools for analyzing the performance parameters as well as specifications of E cars during prototype stage.展开更多
To research the influence of asymmetric brake shoe forces(ABSF)induced by braking failure on the dynamic performance of six-axle locomotive,the static equilibrium model of three-axle bogie and dynamic model for locomo...To research the influence of asymmetric brake shoe forces(ABSF)induced by braking failure on the dynamic performance of six-axle locomotive,the static equilibrium model of three-axle bogie and dynamic model for locomotive are established.The coupling vibration equations of axle hung motor and wheelset are derived.For the air braking,the influence mechanism of ABSF on the wheel-rail asymmetric motion and force characteristics are discussed.It can be found that if the ABSF is applied in the front wheelset,all the wheelsets move laterally in the same direction.Once the ABSF occurs in the middle or rear one,other wheelsets may move laterally towards the opposite direction.The motion amplitude and direction of all wheelsets strictly depend on the resultant moment of suspension yawing moment and brake shoe asymmetric moment.For the asymmetric braking,the free lateral gap of axle-box could increase the wheelset motion amplitude,but could not change the moving direction.In both the straight line and curve,the ABSF may lead to wheelset misaligning motion,intensify the wheel-rail lateral dynamic interaction and deteriorate wheel-rail contact state.Especially for the steering wheelsets,the asymmetric braking increases the wheelset attack angle significantly,which forms the worst braking condition.展开更多
Fluid film bearings are widely used as support elements of rotating shaft for HDD （hard disk drive） spindle motors. Recently, the opportunity for the HDD spindle motors exposed to external vibration has been increas...Fluid film bearings are widely used as support elements of rotating shaft for HDD （hard disk drive） spindle motors. Recently, the opportunity for the HDD spindle motors exposed to external vibration has been increasing because the HDDs are used for various information related equipments such as mobile PCs, car navigation systems. Hence, the rotating shaft has a possibility to come in contact with the bearing and it causes wear or seizure to the bearing surface. In order to avoid the problems, it is extremely important to enhance the dynamic characteristics of the fluid film bearings for spindles. However, verification from both theory and experiment of dynamic characteristics such as spring coefficients and damping coefficients is rare and few. In this paper, the bearing vibration characteristics when the HDD spindle is oscillated are investigated theoretically and experimentally. And then the identification method ofoil film coefficients of fluid film bearing spindles is described.展开更多
文摘为了降低降压变压器的安装空间及磁饱和等因素给铁路功率调节器(railway static power conditioner,RPC)工程应用及治理效果带来的不利影响,模块化多电平换流器的铁路功率调节器(railway static power conditioner of modular multilevel converter,MMC-RPC)成为研究热点。但现有的MMC-RPC控制策略没有考虑电力机车实际负荷功率及电流波动特性对MMC各子模块电容电压影响,使其电容电压波动较大。为此,根据电力机车功率及负荷运行特性,采用混合PWM调制策略,既能满足开关损耗低的要求,又能适应电力机车动态运行特性下MMC-RPC各子模块电容均压波动范围。最后,通过仿真和实验结果验证了MMC-RPC输出性能相对传统二电平RPC的优越性,采用的混合PWM调制策略能够使得MMC-RPC适应电力机车实际负荷功率及电流波动特性,各子模块电容均压波动幅值均有效控制在±5%范围内。
文摘The simulation model of the E car HS2000 including the permanent magnetic direct current motor with the augment magnet winding is constructed based on tests in order to simulate the synthetic performance of the electric car. The performance of E car HS2000 is analyzed by means of modeling and programming according to data acquired during tests. The simulation results show that the performance of E car HS2000 is successfully predicted and the model and the corresponding simulation software are feasible for simulating E cars. They can be used as effective tools for analyzing the performance parameters as well as specifications of E cars during prototype stage.
基金Projects(52072249,51605315)supported by the National Natural Science Foundation of ChinaProject(E2018210052)supported by the Natural Science Foundation of Hebei Province,ChinaProject(TPL1707)supported by the Open Funds for the State Key Laboratory of Traction Power,China。
文摘To research the influence of asymmetric brake shoe forces(ABSF)induced by braking failure on the dynamic performance of six-axle locomotive,the static equilibrium model of three-axle bogie and dynamic model for locomotive are established.The coupling vibration equations of axle hung motor and wheelset are derived.For the air braking,the influence mechanism of ABSF on the wheel-rail asymmetric motion and force characteristics are discussed.It can be found that if the ABSF is applied in the front wheelset,all the wheelsets move laterally in the same direction.Once the ABSF occurs in the middle or rear one,other wheelsets may move laterally towards the opposite direction.The motion amplitude and direction of all wheelsets strictly depend on the resultant moment of suspension yawing moment and brake shoe asymmetric moment.For the asymmetric braking,the free lateral gap of axle-box could increase the wheelset motion amplitude,but could not change the moving direction.In both the straight line and curve,the ABSF may lead to wheelset misaligning motion,intensify the wheel-rail lateral dynamic interaction and deteriorate wheel-rail contact state.Especially for the steering wheelsets,the asymmetric braking increases the wheelset attack angle significantly,which forms the worst braking condition.
文摘Fluid film bearings are widely used as support elements of rotating shaft for HDD （hard disk drive） spindle motors. Recently, the opportunity for the HDD spindle motors exposed to external vibration has been increasing because the HDDs are used for various information related equipments such as mobile PCs, car navigation systems. Hence, the rotating shaft has a possibility to come in contact with the bearing and it causes wear or seizure to the bearing surface. In order to avoid the problems, it is extremely important to enhance the dynamic characteristics of the fluid film bearings for spindles. However, verification from both theory and experiment of dynamic characteristics such as spring coefficients and damping coefficients is rare and few. In this paper, the bearing vibration characteristics when the HDD spindle is oscillated are investigated theoretically and experimentally. And then the identification method ofoil film coefficients of fluid film bearing spindles is described.
