The digital excitation regulator is very popular in the small electric plant. This kind of regulator can im- prove the working condition of generator and its working efficiency. It is on the base of the 80C51 Micro-co...The digital excitation regulator is very popular in the small electric plant. This kind of regulator can im- prove the working condition of generator and its working efficiency. It is on the base of the 80C51 Micro-con- troller. The regulator can automatically finish some functions through the combination of software and hard- ware. Through the experiment we can know it is more intellectual than the traditional analog excitation regu- lator.展开更多
This paper addresses some of the problems related to direct surface temperature measurement of a salient pole synchronous generator excitation winding in rotation. Excitation winding temperature is used for determinin...This paper addresses some of the problems related to direct surface temperature measurement of a salient pole synchronous generator excitation winding in rotation. Excitation winding temperature is used for determining the dynamic limit in a PQ diagram. The paper also addresses procedures of improving the accuracy of surface temperature measurement using the contact DS 18B20 digital temperature probes. The paper also provides experimental results of direct temperature measurement of the excitation winding surface conducted in the salient pole synchronous generator in the rotation.展开更多
基于实时数字仿真系统(real time digital simulation,RTDS)和数字励磁调节器(automatic voltage regulator,AVR)装置构建了物理数字联合仿真平台,并针对AVR辅助控制及限制环节功能可能存在的缺陷设计了包括低频振荡、过励、进相和定子...基于实时数字仿真系统(real time digital simulation,RTDS)和数字励磁调节器(automatic voltage regulator,AVR)装置构建了物理数字联合仿真平台,并针对AVR辅助控制及限制环节功能可能存在的缺陷设计了包括低频振荡、过励、进相和定子过流等项目的试验方案。利用RDTS对某AVR装置进行建模仿真,并在时域范围内比较仿真模型与实际装置对各种扰动的动态响应,验证了试验方法和仿真建模的正确性,并分析指出了该AVR装置在强励限制上特性与国标要求不一致之处。展开更多
共振激发控制技术是提高四极离子阱分辨率、灵敏度，实现其多级质谱分析的关键技术。针对质谱仪小型化趋势，提出基于现场可编程门阵列（filed-programmable gate array，FPGA）软件实现直接数字合成器（direct digital synthesizer，DD...共振激发控制技术是提高四极离子阱分辨率、灵敏度，实现其多级质谱分析的关键技术。针对质谱仪小型化趋势，提出基于现场可编程门阵列（filed-programmable gate array，FPGA）软件实现直接数字合成器（direct digital synthesizer，DDS）信号幅度调制的方法，开发出数字式共振激发控制技术，研制出结构更简单的共振激发控制系统。在对性能要求较高的电喷雾离子源-矩形离子阱质谱仪中，应用这套系统实现了单质荷比选择离子、三级质谱分析和600-2000Thomson质荷比范围的全扫描等功能。相比使用模拟技术实现幅度调制的控制单元，数字式共振激发控制单元的功耗只有其10％，系统性能也满足四极离子阱的需求。展开更多
The development of a novel push-type ultrasonic endoscope is described in which probe rotation is accomplished by a small motor situated near the transducer. A digital FPGA-based ultrasound imaging system is implement...The development of a novel push-type ultrasonic endoscope is described in which probe rotation is accomplished by a small motor situated near the transducer. A digital FPGA-based ultrasound imaging system is implemented which uses coded excitation to increase the SNR and penetration depth, with probe rotation accomplished by a small motor situated near the transducer replacing the external motor and the long steel wire used in other ultrasonic endoscopes. The apparatus is tested continuously for 300 hours with no obvious problems. The coded excitation, digital quadrature demodulation imaging system can obtain ultrasonic images of higher quality and more information of the echo is preserved compared with the analog imaging system, because the analog digital conversion is moved to the first step of the signal processing.The digital imaging system possesses a higher SNR resulting in a sharp image. Locating the motor near the probe improves the consistency of rotational speed in comparison with external guide-wire rotation, and increases the image quality and life-span of these devices.展开更多
文摘The digital excitation regulator is very popular in the small electric plant. This kind of regulator can im- prove the working condition of generator and its working efficiency. It is on the base of the 80C51 Micro-con- troller. The regulator can automatically finish some functions through the combination of software and hard- ware. Through the experiment we can know it is more intellectual than the traditional analog excitation regu- lator.
文摘This paper addresses some of the problems related to direct surface temperature measurement of a salient pole synchronous generator excitation winding in rotation. Excitation winding temperature is used for determining the dynamic limit in a PQ diagram. The paper also addresses procedures of improving the accuracy of surface temperature measurement using the contact DS 18B20 digital temperature probes. The paper also provides experimental results of direct temperature measurement of the excitation winding surface conducted in the salient pole synchronous generator in the rotation.
文摘基于实时数字仿真系统(real time digital simulation,RTDS)和数字励磁调节器(automatic voltage regulator,AVR)装置构建了物理数字联合仿真平台,并针对AVR辅助控制及限制环节功能可能存在的缺陷设计了包括低频振荡、过励、进相和定子过流等项目的试验方案。利用RDTS对某AVR装置进行建模仿真,并在时域范围内比较仿真模型与实际装置对各种扰动的动态响应,验证了试验方法和仿真建模的正确性,并分析指出了该AVR装置在强励限制上特性与国标要求不一致之处。
文摘共振激发控制技术是提高四极离子阱分辨率、灵敏度，实现其多级质谱分析的关键技术。针对质谱仪小型化趋势，提出基于现场可编程门阵列（filed-programmable gate array，FPGA）软件实现直接数字合成器（direct digital synthesizer，DDS）信号幅度调制的方法，开发出数字式共振激发控制技术，研制出结构更简单的共振激发控制系统。在对性能要求较高的电喷雾离子源-矩形离子阱质谱仪中，应用这套系统实现了单质荷比选择离子、三级质谱分析和600-2000Thomson质荷比范围的全扫描等功能。相比使用模拟技术实现幅度调制的控制单元，数字式共振激发控制单元的功耗只有其10％，系统性能也满足四极离子阱的需求。
基金Supported by the Project of the Education Department of China(106048)the National High Technology Researchand Development Program of China(2007AA04Z339)the National Natural Science Foundation of China(6082700)
文摘The development of a novel push-type ultrasonic endoscope is described in which probe rotation is accomplished by a small motor situated near the transducer. A digital FPGA-based ultrasound imaging system is implemented which uses coded excitation to increase the SNR and penetration depth, with probe rotation accomplished by a small motor situated near the transducer replacing the external motor and the long steel wire used in other ultrasonic endoscopes. The apparatus is tested continuously for 300 hours with no obvious problems. The coded excitation, digital quadrature demodulation imaging system can obtain ultrasonic images of higher quality and more information of the echo is preserved compared with the analog imaging system, because the analog digital conversion is moved to the first step of the signal processing.The digital imaging system possesses a higher SNR resulting in a sharp image. Locating the motor near the probe improves the consistency of rotational speed in comparison with external guide-wire rotation, and increases the image quality and life-span of these devices.
