该文针对多源时变干扰影响的双三相永磁同步电机系统,研究其基波平面内的调速控制问题和谐波平面内的谐波电流抑制问题。首先,在基波平面采用非串级控制结构,通过构造广义比例积分观测器(generalized proportional integral observer,GP...该文针对多源时变干扰影响的双三相永磁同步电机系统,研究其基波平面内的调速控制问题和谐波平面内的谐波电流抑制问题。首先,在基波平面采用非串级控制结构,通过构造广义比例积分观测器(generalized proportional integral observer,GPIO)估计转速环的多源快变干扰;然后,针对q轴电流的过流保护问题,在传统比例微分反馈控制器的基础上利用障碍函数设计思想,结合干扰估计信息,得到基于GPIO的电流约束复合控制器;其次,在谐波平面,通过设计2个GPIO精准估计电流环的多源快变干扰,并与比例反馈控制器结合形成复合控制器来抑制2个电流环中的谐波电流。最后,给出严谨的稳定性分析,并通过对比实验验证所提方法的有效性。展开更多
Based on three-dimensional （3D） acceleration sensing, an intelligent particle spy capable of detecting, transferring, and storing data, is proposed under the name of Particle Measurement Sensor （PMS）. A prototype ...Based on three-dimensional （3D） acceleration sensing, an intelligent particle spy capable of detecting, transferring, and storing data, is proposed under the name of Particle Measurement Sensor （PMS）. A prototype 60-mm-dia PMS was tested to track its freefall in terms of velocity and displacement, and served as a particle spy in a fluidized bed delivering the in situ acceleration information it detects. With increasing superficial gas velocity in the fluidized bed, the acceleration felt by PMS was observed to increase. The variance of the signals, which reflect the fluctuation, increased at first, reaching a maximum at the gas velocity （Uc） which marks the transition from bubbling to turbulent fluidization. Through probability density distribution （PDD） analysis, the PDD peak can be divided into the emulsion phase peak and the bubble phase peak. The average acceleration of emulsion and bubble phase increased, while the variance of both phases reached a maximum at Uc, at the same time. However, the difference between the variances of two phases reached the maximum at Uc. Findings of this study indicate that PMS can record independent in situ information. Further, it can provide other in situ measurements when equipped with additional multi-functional sensors.展开更多
In 2002, construction of the Three Gorges project is characterized by its too high workload in installa-tion of metal structures and units following the concrete placement, especially in erection and test and regulati...In 2002, construction of the Three Gorges project is characterized by its too high workload in installa-tion of metal structures and units following the concrete placement, especially in erection and test and regulation of metal structures, and installation of main components of units. Just before the rush time for operation of the units with construction of the project simultaneously, the preparatory work for the phased acceptance and management must be developed widely. The incidents and defaults in construction quality must be inspected, analyzed and treated in earnest prior to acceptance and impoundment of the reservoir. The removal of the up and downstream cofferdams are being ex-ecuted smoothly, but more attention shall be paid on the cleaning of the construction pits where there are still a great number of rocks to be excavated. The processing control and factory inspection shall be supervised. The field erectionand test and regulation shall be arranged elaborately. This year most of the metal structures incorporated with update technology will be in the test and regulation stage. The project acceptance is not only an essential procedure legally, butalso an overall inspection of the works.展开更多
以两种固-液型相变材料共混所得的复合相变材料（CPCM）为芯层,以尼龙6（PA6）切片为皮层,采用自制的复合纺丝组件通过不同于传统的熔融纺丝法,得到PA6/CPCM储能调温初生纤维,将初生纤维在80℃下拉伸5倍,制得PA6/CPCM储能调温纤维,并对...以两种固-液型相变材料共混所得的复合相变材料（CPCM）为芯层,以尼龙6（PA6）切片为皮层,采用自制的复合纺丝组件通过不同于传统的熔融纺丝法,得到PA6/CPCM储能调温初生纤维,将初生纤维在80℃下拉伸5倍,制得PA6/CPCM储能调温纤维,并对其结构性能进行了表征。结果表明：PA6/CPCM初生纤维呈皮芯结构,直径约为95μm;所得纤维中CPCM质量分数约为32.9%,熔融相变温度为18.50~30.89℃,结晶相变温度为7.78~18.68℃,熔融焓、结晶焓分别为66.12,64.93 J/g;当CPCM注入量为8 m L/h时,PA6/CPCM储能调温纤维的线密度为15.57 dtex,断裂强度为2.76 c N/dtex,断裂伸长率为16.71%,该纤维可应用于冬季保暖外套中。展开更多
文摘该文针对多源时变干扰影响的双三相永磁同步电机系统,研究其基波平面内的调速控制问题和谐波平面内的谐波电流抑制问题。首先,在基波平面采用非串级控制结构,通过构造广义比例积分观测器(generalized proportional integral observer,GPIO)估计转速环的多源快变干扰;然后,针对q轴电流的过流保护问题,在传统比例微分反馈控制器的基础上利用障碍函数设计思想,结合干扰估计信息,得到基于GPIO的电流约束复合控制器;其次,在谐波平面,通过设计2个GPIO精准估计电流环的多源快变干扰,并与比例反馈控制器结合形成复合控制器来抑制2个电流环中的谐波电流。最后,给出严谨的稳定性分析,并通过对比实验验证所提方法的有效性。
基金supported by the Foundation for Natural Scientific Foundation of China (No. 20606020, No. 20736004, No. 20736007)
文摘Based on three-dimensional （3D） acceleration sensing, an intelligent particle spy capable of detecting, transferring, and storing data, is proposed under the name of Particle Measurement Sensor （PMS）. A prototype 60-mm-dia PMS was tested to track its freefall in terms of velocity and displacement, and served as a particle spy in a fluidized bed delivering the in situ acceleration information it detects. With increasing superficial gas velocity in the fluidized bed, the acceleration felt by PMS was observed to increase. The variance of the signals, which reflect the fluctuation, increased at first, reaching a maximum at the gas velocity （Uc） which marks the transition from bubbling to turbulent fluidization. Through probability density distribution （PDD） analysis, the PDD peak can be divided into the emulsion phase peak and the bubble phase peak. The average acceleration of emulsion and bubble phase increased, while the variance of both phases reached a maximum at Uc, at the same time. However, the difference between the variances of two phases reached the maximum at Uc. Findings of this study indicate that PMS can record independent in situ information. Further, it can provide other in situ measurements when equipped with additional multi-functional sensors.
文摘In 2002, construction of the Three Gorges project is characterized by its too high workload in installa-tion of metal structures and units following the concrete placement, especially in erection and test and regulation of metal structures, and installation of main components of units. Just before the rush time for operation of the units with construction of the project simultaneously, the preparatory work for the phased acceptance and management must be developed widely. The incidents and defaults in construction quality must be inspected, analyzed and treated in earnest prior to acceptance and impoundment of the reservoir. The removal of the up and downstream cofferdams are being ex-ecuted smoothly, but more attention shall be paid on the cleaning of the construction pits where there are still a great number of rocks to be excavated. The processing control and factory inspection shall be supervised. The field erectionand test and regulation shall be arranged elaborately. This year most of the metal structures incorporated with update technology will be in the test and regulation stage. The project acceptance is not only an essential procedure legally, butalso an overall inspection of the works.
文摘以两种固-液型相变材料共混所得的复合相变材料（CPCM）为芯层,以尼龙6（PA6）切片为皮层,采用自制的复合纺丝组件通过不同于传统的熔融纺丝法,得到PA6/CPCM储能调温初生纤维,将初生纤维在80℃下拉伸5倍,制得PA6/CPCM储能调温纤维,并对其结构性能进行了表征。结果表明：PA6/CPCM初生纤维呈皮芯结构,直径约为95μm;所得纤维中CPCM质量分数约为32.9%,熔融相变温度为18.50~30.89℃,结晶相变温度为7.78~18.68℃,熔融焓、结晶焓分别为66.12,64.93 J/g;当CPCM注入量为8 m L/h时,PA6/CPCM储能调温纤维的线密度为15.57 dtex,断裂强度为2.76 c N/dtex,断裂伸长率为16.71%,该纤维可应用于冬季保暖外套中。
