Combining direct compensation current and DC-link voltage controls in a multilevel cascade STATCOM for fast response requirement

Author(s):  
Ching-Huan Liao ◽  
Wei-Neng Chang
Author(s):  
M.J. Kim ◽  
L.C. Liu ◽  
S.H. Risbud ◽  
R.W. Carpenter

When the size of a semiconductor is reduced by an appropriate materials processing technique to a dimension less than about twice the radius of an exciton in the bulk crystal, the band like structure of the semiconductor gives way to discrete molecular orbital electronic states. Clusters of semiconductors in a size regime lower than 2R {where R is the exciton Bohr radius; e.g. 3 nm for CdS and 7.3 nm for CdTe) are called Quantum Dots (QD) because they confine optically excited electron- hole pairs (excitons) in all three spatial dimensions. Structures based on QD are of great interest because of fast response times and non-linearity in optical switching applications.In this paper we report the first HREM analysis of the size and structure of CdTe and CdS QD formed by precipitation from a modified borosilicate glass matrix. The glass melts were quenched by pouring on brass plates, and then annealed to relieve internal stresses. QD precipitate particles were formed during subsequent "striking" heat treatments above the glass crystallization temperature, which was determined by differential thermal analysis.


The Analyst ◽  
2020 ◽  
Vol 145 (1) ◽  
pp. 122-131 ◽  
Author(s):  
Wanda V. Fernandez ◽  
Rocío T. Tosello ◽  
José L. Fernández

Gas diffusion electrodes based on nanoporous alumina membranes electrocatalyze hydrogen oxidation at high diffusion-limiting current densities with fast response times.


2020 ◽  
Author(s):  
SMITA GAJANAN NAIK ◽  
Mohammad Hussain Kasim Rabinal

Electrical memory switching effect has received a great interest to develop emerging memory technology such as memristors. The high density, fast response, multi-bit storage and low power consumption are their...


2020 ◽  
Vol 38 (8A) ◽  
pp. 1187-1199
Author(s):  
Qaed M. Ali ◽  
Mohammed M. Ezzalden

BLDC motors are characterized by electronic commutation, which is performed by using an electric three-phase inverter. The direct control system of the BLDC motor consists of double loops; including the inner-loop for current regulating and outer-loop for speed control. The operation of the current controller requires feedback of motor currents; the conventional current controller uses two current sensors on the ac side of the inverter to measure the currents of two phases, while the third current would be accordingly calculated. These two sensors should have the same characteristics, to achieve balanced current measurements. It should be noted that the sensitivity of these sensors changes with time. In the case of one sensor fails, both of them must be replaced. To overcome this problem, it is preferable to use one sensor instead of two. The proposed control system is based on a deadbeat predictive controller, which is used to regulate the DC current of the BLDC motor. Such a controller can be considered as digital controller mode, which has fast response, high precision and can be easily implemented with microprocessor. The proposed control system has been simulated using Matlab software, and the system is tested at a different operating condition such as low speed and high speed.


2017 ◽  
Vol 2 (3) ◽  
pp. 341-346
Author(s):  
Vina Meliana

Providing compensation to employees is important for every company, including PT INTI to retain qualified employees today and in the future. PT INTI is a company whose primary based as telecommunication contractor located in Bandung. This study was conducted to determine the effect between direct financial compensation variables and indirect financial compensation toward employee performance. This research uses the descriptive method and data analysis with the path and regression analysis. The result of this research is a descriptive condition of direct and indirect financial compensation in PT INTI in the reality of 2008 is not good based on continuum line where the average percentage is 30,21% where employee expectation to incentive and celebration of the holiday is large. In addition, the simultaneous test shows that there is no linear relationship between direct compensation and indirect compensation for employee performance at PT INTI. Keywords: compensation, employee performance, financial compensation


Author(s):  
Xiuying Ren ◽  
Sida Li ◽  
Yueda Liu ◽  
Yan Li ◽  
Yikai Su
Keyword(s):  

1994 ◽  
Vol 29 (2-3) ◽  
pp. 293-308
Author(s):  
J. Koponen ◽  
M. Virtanen ◽  
H. Vepsä ◽  
E. Alasaarela

Abstract Three-dimensional (3-D) mathematical models of water currents, transport, mixing, reaction kinetic, and interactions with bottom and air have been used in Finland regularly since 1982 and applied to about 40 cases in large lakes, inland seas and their coastal waters. In each case, model validity has been carefully tested with available flow velocity measurements, tracer studies and water quality observations. For operational use, i.e., for spill combatting and sea rescue, the models need fast response, proven validity and illustrative visualization. In 1987-90, validated models were implemented for operational use at five sea areas along the Finnish coast. Further validation was obtained in model applications from nine documented or arranged cases and from seven emergency situations. Sensitivity tests supplement short-term validation. In the Bothnian Sea, it was nescessary to start the calculation of water currents three days prior to the start of the experiment to reduce initial inaccuracies and to make the coastal transport estimates meaningful.


Author(s):  
Sadegh Vaez-Zadeh

In this chapter, three control methods recently developed for or applied to electric motors in general and to permanent magnet synchronous (PMS) motors, in particular, are presented. The methods include model predictive control (MPC), deadbeat control (DBC), and combined vector and direct torque control (CC). The fundamental principles of the methods are explained, the machine models appropriate to the methods are derived, and the control systems are explained. The PMS motor performances under the control systems are also investigated. It is elaborated that MPC is capable of controlling the motor under an optimal performance according to a defined objective function. DBC, on the other hand, provides a very fast response in a single operating cycle. Finally, combined control produces motor dynamics faster than one under VC, with a smoother performance than the one under DTC.


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