scholarly journals The control system for the magnetic suspension comparator system for vacuum-to-air mass dissemination

ACTA IMEKO ◽  
2017 ◽  
Vol 6 (2) ◽  
pp. 75 ◽  
Author(s):  
Corey Stambaugh

<p dir="LTR" align="JUSTIFY">High precision mass comparisons are typically performed such that both masses are measured under nearly identical conditions. However, there are situations where an artefact needs to be calibrated against a standard kept under different conditions. For example, the new realization of the kilogram will be carried out in vacuum but the majority of calibrations services are performed at atmospheric pressure. At the National Institute of Standards and Technology we have developed an apparatus to perform direct mass comparison under such a condition using magnetic suspension. The stability of the magnetically suspended portion of the system plays a large role in the overall uncertainty of a measurement. Here, the control system for the magnetic suspension and the improvements that have been made to improve stability are described.</p>

2003 ◽  
Vol 3 ◽  
pp. 297-307
Author(s):  
V.V. Denisov

An approach to the study of the stability of non-linear multiply connected systems of automatic control by means of a fast Fourier transform and the resonance phenomenon is considered.


2021 ◽  
Vol 13 (11) ◽  
pp. 6388
Author(s):  
Karim M. El-Sharawy ◽  
Hatem Y. Diab ◽  
Mahmoud O. Abdelsalam ◽  
Mostafa I. Marei

This article presents a control strategy that enables both islanded and grid-tied operations of a three-phase inverter in distributed generation. This distributed generation (DG) is based on a dramatically evolved direct current (DC) source. A unified control strategy is introduced to operate the interface in either the isolated or grid-connected modes. The proposed control system is based on the instantaneous tracking of the active power flow in order to achieve current control in the grid-connected mode and retain the stability of the frequency using phase-locked loop (PLL) circuits at the point of common coupling (PCC), in addition to managing the reactive power supplied to the grid. On the other side, the proposed control system is also based on the instantaneous tracking of the voltage to achieve the voltage control in the standalone mode and retain the stability of the frequency by using another circuit including a special equation (wt = 2πft, f = 50 Hz). This utilization provides the ability to obtain voltage stability across the critical load. One benefit of the proposed control strategy is that the design of the controller remains unconverted for other operating conditions. The simulation results are added to evaluate the performance of the proposed control technology using a different method; the first method used basic proportional integration (PI) controllers, and the second method used adaptive proportional integration (PI) controllers, i.e., an Artificial Neural Network (ANN).


2014 ◽  
Vol 1006-1007 ◽  
pp. 575-580
Author(s):  
Qing Xie Chen ◽  
Jing Jing Chen ◽  
Yi Biao Fan

Targeting development of control system of a permanent magnet synchronous motor applied to high precision requirement, A strategy is researched to develop a single chip with built-in sensor-less control algorithm which is used as the control core of PMSM control system, the composition of the hardware and the realization of software of the chip are designed, and the simulation experiment is carried out to verify feasibility and rationality of the control strategy as well.


2014 ◽  
Vol 628 ◽  
pp. 186-189
Author(s):  
Meng Xiong Zeng ◽  
Jin Feng Zhao ◽  
Wen Ouyang

The control system performance requirement was divided into three parts. They were the stability, rapidity and accuracy. The time-frequency domain analysis in the requirements of three performance were measured through quantitative performance index. The mutual restriction of time-frequency performance and system characteristic parameters of normal second order was discussed. The correlation of system time-frequency performance index was established. The relationship between time-frequency performance indexes in standard two order system was extended to higher order system. The mutually constraining and time-frequency correlation between each performance index was obtained by analysis and calculation. The work had been done above had practical significance to reflect the system dynamic performance in different analytical domains.


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