scholarly journals Orbit compensation for the time-varying elliptically polarized wiggler with switching frequency at 100 Hz

2002 ◽  
Author(s):  
O. Singh ◽  
S. Krinsky
Keyword(s):  
Switching Frequency ◽  
Time Varying ◽  
Elliptically Polarized

Orbit compensation for the time varying elliptically polarized wiggler (invited)

1996 ◽  
Vol 67 (9) ◽  
pp. 3346-3346 ◽  
Author(s):  
O. Singh ◽  
S. Krinsky ◽  
P.M. Ivanov ◽  
E.A. Medvedko
Keyword(s):  
Time Varying ◽  
Elliptically Polarized

The propagation of a transverse electromagnetic wave in a nonlinear, anisotropic, time-dependent plasma medium

1968 ◽  
Vol 46 (7) ◽  
pp. 889-905
Author(s):  
Robert J. Papa
Keyword(s):  
Energy Balance ◽  
Plane Wave ◽  
Electron Temperature ◽  
Electron Density ◽  
Balance Equation ◽  
Energy Balance Equation ◽  
Time Dependent ◽  
Time Varying ◽  
Circularly Polarized ◽  
Elliptically Polarized

In a previous paper, a one-dimensional, inhomogeneous model was considered in describing the nonlinear interaction of a radiofrequency plane wave with a time-varying plasma. This paper extends the analysis to the anisotropic case, in which an elliptically polarized plane wave incident upon an electron-density profile induces changes in the electron density and electron temperature. A d-c. magnetic field parallel to the electron-density gradients causes the elliptically polarized wave to split into two distinct modes, a right-hand circularly polarized and a left-hand circularly polarized mode. The two modes are coupled through an energy-balance equation that governs the behavior of the electron temperature. The time-dependent response of the plasma may be found by numerically integrating an energy-balance equation and a continuity equation. The solution to the wave equation for the time-varying, inhomogeneous, anisotropic medium may be obtained through the use of the WKB approximation. The time scales for electron-temperature and electron-density changes are found to vary with incident flux, incident-wave ellipticity, and appropriate normalized plasma parameters.

scholarly journals SYNCHRONIZATION PHENOMENA IN VAN DER POL OSCILLATORS COUPLED BY A TIME-VARYING RESISTOR

2007 ◽  
Vol 17 (10) ◽  
pp. 3565-3569 ◽  
Author(s):  
YOKO UWATE ◽  
YOSHIFUMI NISHIO
Keyword(s):  
Switching Frequency ◽  
Time Varying ◽  
Van Der Pol ◽  
Van Der Pol Oscillators ◽  
Computer Calculations

In this study, synchronization phenomena observed in van der Pol oscillators coupled by a time-varying resistor are investigated. We realize the time-varying resistor by switching a positive and a negative resistor periodically. By carrying out circuit experiments and computer calculations, interesting synchronization phenomena can be confirmed to be generated in this system. Namely, the synchronization states change according to the switching frequency of the time-varying resistor.

Efficient Control of a Switched Inertance Hydraulic Converter With a Time-Varying Load

2021 ◽  
Author(s):  
Chenggang Yuan ◽  
Andrew Plummer ◽  
Min Pan
Keyword(s):  
High Efficiency ◽  
High Energy ◽  
Pi Controller ◽  
Control Flow ◽  
Switching Frequency ◽  
Time Varying ◽  
Hydraulic Systems ◽  
Controlled Systems ◽  
Loading Effects ◽  
And Control

Abstract Switched inertance hydraulic converters (SIHC) are new digital hydraulic devices which provide an alternative to conventional proportional or servo valve-controlled systems in hydraulic fluid power. SIHCs can adjust and control flow and pressure by means of using digital control signals that do not rely on throttling the flow and dissipation of power, and provide hydraulic systems with high-energy efficiency, good controllability, and insensitivity to contamination. A flow booster is one configuration of SIHCs which can deliver more flow than the supply flow. In this article, the loading effects of SIHCs are investigated by applying a time-varying load on the flow booster. A control system consisting of a PI controller and a switching frequency optimizer was designed to operate a flow booster at its optimal switching frequencies and switching ratios to maximize system efficiency when the load varies. Simulated results showed that the flow booster with the proposed controller has very good dynamic response and can be operated at an average efficiency of 70% with a time-varying load. Compared with only using a PI controller, the proposed controller can improve the overall efficiency by up to 20%. As time-varying loading conditions are commonly found in hydraulic applications, this work constitutes an important contribution to the design and development of high-efficiency SIHCs.

Comparison of Dc-Dc SEPIC, CUK and Flyback Converters Based LED Drivers

2020 ◽  
pp. 99-107
Author(s):  
Erdal Sehirli
Keyword(s):  
Integrated Circuit ◽  
Closed Loop ◽  
Input Voltage ◽  
Open Loop ◽  
Current Sensor ◽  
Switching Frequency ◽  
Led Driver ◽  
Advantages And Disadvantages ◽  
Led Drivers ◽  
Conduction Mode

This paper presents the comparison of LED driver topologies that include SEPIC, CUK and FLYBACK DC-DC converters. Both topologies are designed for 8W power and operated in discontinuous conduction mode (DCM) with 88 kHz switching frequency. Furthermore, inductors of SEPIC and CUK converters are wounded as coupled. Applications are realized by using SG3524 integrated circuit for open loop and PIC16F877 microcontroller for closed loop. Besides, ACS712 current sensor used to limit maximum LED current for closed loop applications. Finally, SEPIC, CUK and FLYBACK DC-DC LED drivers are compared with respect to LED current, LED voltage, input voltage and current. Also, advantages and disadvantages of all topologies are concluded.

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