共查询到20条相似文献,搜索用时 62 毫秒
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针对交流恒流的使用要求,提出了一种不对称规则采样法,利用ATMEGA16单片机的16位计时器生成SP-WM信号,驱动4个IGBT管组成的逆变主电路,通过LC滤波后送到输出端,同时在输出端进行采样,将采样值反馈给单片机。单片机根据采样值通过调整配置寄存器的值输出幅度和频率可变的SPWM信号,从而调整输出电压的幅度或频率,实现电流的恒定输出。实验表明,通过该种系统实现的交流恒流源精度高、可控性好、成本低。 相似文献
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调频毫米波近程雷达半实物仿真综合测试系统研究 总被引:8,自引:1,他引:7
为了满足非大气窗口毫米波近程雷达系统性能测试的需要,通过对三角波线性调频连续波近程雷达测距的分析,以典型弹道某靶机为例,建立了基于LabVIEW8.5的半实物时域、频域和嵌套调用MATLAB7的Margenau-Hill调制域综合试验平台,结果表明混频器差频信号真实地反映了弹目视在距离的变化,与传统测试系统相比,基于虚拟仪器技术的综合测试系统,具有可操作性强、功能强大、可实现高速数据的自动采集和测距以及时频分析的特点,在工程实际中具有广阔的应用前景,同时也分析了引起系统测距误差的原因. 相似文献
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基于PIC单片机的交流伺服电机控制系统研究 总被引:1,自引:0,他引:1
介绍了基于PIC18F458单片机实现交流伺服电机控制的一种方案,能实现对伺服电机运转的平稳控制。该方案在电机消防炮转角控制中得到了成功的应用,并且控制过程非常平稳,定位精确度也很高。 相似文献
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自适应阈值的超变分正则化图像盲复原 总被引:1,自引:2,他引:1
针对一阶总变分盲复原块效应严重的问题,提出了一种自适应阈值的超变分正则化图像盲复原方法来恢复点扩散函数未知的退化图像。对总变分形式进行了分析,提出了超变分正则项,并给出了代价函数的数学模型。用估计的图像噪声确定模型中阈值的大小,然后引进3个辅助变量等价转化代价函数,以便简化后续计算并提高复原效果。最后,利用半二次规整化对模型迭代求解。实验结果表明,复原后图像细节增加且块效应减少,相对于目前已有的方法,信噪比提高了近1dB。恢复效果表明该方法具有较大的实用价值。 相似文献
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本文利用单片机技术,实现了智能交流单相制动电磁铁起动过程、吸持过程、释放过程的实时控制,在大量实验的基础上实现了整个运行过程的最优控制。为研制出性能优良、工作可靠的智能交流单相制动电磁铁奠定了基础。 相似文献
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S. V. Korotkov Yu. V. Aristov A. L. Zhmodikov A. K. Kozlov D. A. Korotkov 《Instruments and Experimental Techniques》2014,57(4):431-436
Electric circuits of high-power switches based on assemblies of diodes that are connected in series to reverse switch-on dynistors (RSDs) are considered. They allow RSDs to be efficiently used in the modes of switching high-power weakly decaying current pulses, which were previously impossible because of high energy losses in dynistors during the reverse-current flow. The results of a comparative study of high-voltage (24 kV) diode-dynistor switches under the conditions of switching current pulses with an amplitude of 50 kA and a damping decrement of 1.3 are presented. The possibility of increasing the switched power is shown. 相似文献
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通过对磁粉离合器工作特性的研究,设计了行星轮式专用磁粉离合器,提出了交流电机与专用磁粉离合器组合装置实现无级调速的新方案,经分析计算、调试及试验,新方案体现了较好的调速性能。 相似文献
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A combined mechanical-electronic system for a smooth linear control of the demagnetizing field is described. Actual demagnetizing curves obtained for some igneous rocks are given to illustrate good functioning of the apparatus in paleomagnetic research. 相似文献
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Kyungnam Kim Hyun Chung 《The International Journal of Advanced Manufacturing Technology》2017,90(5-8):1253-1263
The wire melting phenomenon in alternating current gas metal arc welding (AC-GMAW) process should be carefully observed and analyzed since it is one of the most important representative characteristics of GMAW process. In this study, a new form of wire melting rate equation for AC-GMAW process is proposed based on energy conservation theory and arc physics. Using experimental data, the wire melting rate coefficients of AC-GMAW are obtained through nonlinear regression analysis. The wire melting rate is influenced not only by the current waveform, electrode polarity, and droplet size but also by the shape of the wire tip. That is, if the wire tip becomes more slender, arc heating has more influence on the wire melting. Using the wire melting rate proposed in this research, the uncertainty of calculating wire melting rate coefficients of AC-GMAW can be excluded comparing to existing method. 相似文献
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We present control circuits designed for electrochemically etching, reproducibly sharp STM probes. The design uses an Arduino UNO microcontroller to allow for both ac and dc operation, as well as a comparator driven shut-off that allows for etching to be stopped in 0.5-1 μs. The Arduino allows the instrument to be customized to suit a wide variety of potential applications without significant changes to hardware. Data is presented for coarse chemical etching of 80:20 platinum-iridium, tungsten, and nickel tips. 相似文献
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场指纹法(FSM)是一种基于电位阵列的金属管道在线腐蚀监测方法。传统的直流FSM(DCFSM)是在管道中通直流电流激励,通过监测电极间的电压变化推算出管道内部腐蚀。DCFSM在缝隙腐蚀监测方面,侧重于监测缝隙的起始及扩展方向。而在深度检测方面,由于DCFSM每个电极对间仅有一个电压值用于求解腐蚀,因而只能使用经验公式,检测精度低。交流场指纹法(ACFSM)核心是将现有的DCFSM的电流激励换为交流,通过变频获得电极对间多个频率点的电压值;利用多个电压值求解缝隙腐蚀深度,提高缝隙腐蚀深度检测精度。ACFSM依据交流电流在管道内分布满足趋肤效应,不同频率的电流在金属中的渗透深度不同,测量电极间的电压也不同。本文在介绍ACFSM原理基础上,创新地提出了一种依据多频电压值求解FC值随频率的变化曲线,利用曲线导数值来计算管道内缝隙腐蚀深度的方法。理论分析和实验表明,本文提出的方法可以精确地检测缝隙腐蚀的深度,弥补了DCFSM在缝隙腐蚀监测精度上的不足。 相似文献
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J.L. Camas-Anzueto J.B. Roblero-Galdámez R. Vázquez-Sánchez C. García-Lara G. Anzueto-Sánchez M. Pérez-Patricio S. Mendoza-Vázquez A. Medina-Santiago 《Measurement》2013
This paper proposes and demonstrates a novel alternative to measure alternating current (AC) in an indirect manner, based on the interrogation of an Erbium-doped all-fiber laser. The principle of operation is based on sensing the temperature of an electrical wire AWG-22 caused by Joule effect. The heat transfer between a sensing Fiber Bragg Grating and the electrical wire modulates the intensity of the optical output power of the fiber laser. The intensity variation of the fiber laser is caused by the wavelength overlapping process into the fiber laser. The advantage of the proposed alternative is measuring AC current through the optical power from the fiber laser. The linear increment of optical output power as a function of temperature allows for the measurement of the AC current, which is an advantage over other methods. 相似文献