Search

This article comprises a design, simulation, development, and testing of 500-V, 4-A dc power supply based on the zero voltage switching (ZVS) scheme. Resonant converters have many variants. In this article, quasi-resonant converter (QRC)-ZVS-half bridge-constant frequency type has been used which is generally employed for fixed load application, but in the proposed novel design, tank circuit has been designed in such a way to keep ZVS instant intact even in the case of variable load conditions. Four modules of resonant buck converter of 125 V, 4 A each, have been connected in series to obtain the desired output. The proposed power supply has four sections, such as 12-pulse rectifier transformer, rectifier unit, resonant buck converter followed by a filter unit. A simulation study of the proposed topology was carried out using Power Simulation (PSIM) software. A hardware model of 2 kW consisting of four modules was implemented and tested on resistive load for different scenarios required by control grid (CG) biasing application for tetrode tube; results were analyzed for various modes of operation and ZVS profile was observed for each mode of operation depicting the intact ZVS instant with variable load. Power supply efficiency was measured using an energy analyzer which comes out to be ~90%. [ABSTRACT FROM AUTHOR]

The low frequency tuned amplifiers as well as oscillators are very difficult to design because the size of inductor becomes very large. It is impossible to realize such a large value of inductor practically. This paper presents an alternate method of using simulated inductor instead of passive component L at low frequencies. The design of simulated inductor for low frequency amplifiers and oscillators are presented. The simulation is done using the analog simulation software PSPICE and the results are shown graphically using MATLAB [ABSTRACT FROM AUTHOR]

Conventional pulse-frequency-modulated (PFM) zero-current switching series resonant (SR) inverter-fed voltage-multiplier-based high-voltage dc power supplies have nearly zero switching loss. However, they have limitations of poor controllability at light load and large output voltage ripple at low switching frequencies. To address these problems, this letter proposes a new control scheme that is based on digitally tuning tank capacitance and slightly varying pulse frequency of SR inverter. For the realization of the proposed control approach, the tank circuit of the resonant inverter is made up of several tank capacitors that are switched into or out of the tank circuit by electromechanical switches. By digitally modulating the tank capacitance, the output voltage changes in steps. The regulation of output voltage between two adjacent steps is achieved by slightly varying the pulse frequency. The proposed control scheme has several features, namely, a wide range of output voltage controllability even at light loads, less output voltage ripple, and less current stress on the inverter's power switches at light loads. Therefore, the proposed control approach alleviates most of the problems associated with conventional PFM. Experimental results obtained from a scaled-down laboratory prototype are presented to verify the effectiveness of the proposed system. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we discuss the bit pattern effect on optical clock signals recovered using tank circuits and using birefringent resonators. For the first time we compare the bit pattern dependence of the clock signals recovered from both schemes. We show that a birefringent resonator can recover the clock for the same number of consecutive zeros as the optical tank circuit. We also show quantitatively that the fluctuation of the clock signal amplitude is less for the birefringent resonator than the optical tank circuit. These results are obtained numerically and confirmed experimentally. [Copyright &y& Elsevier]

Hybrid simulation was performed to analyze the response of the real-time reflection-type radio frequency single-electron transistor (RF-SET) measurement system. A compact and physically-based analytical SET model, which was validated with a Monte Carlo simulator, was used to simulate the SET characteristics, while SPICE equivalent circuits were implemented to simulate all other components of the RF-SET measurement system. The impact of various key parameters on the RF-SET response was demonstrated for a carrier frequency much less than I/e ( is the typical current through the SET). It was revealed that an inevitable feed-through loss between the tank circuit and the cryogenic amplifier, and high-frequency parasitics of the inductor degrade the RF-SET performance significantly. As such, they have to be optimized to experimentally realize the shot-noise-limited charge sensitivity. [ABSTRACT FROM PUBLISHER]

Abstract: Results of the recent experiments have clear and convincingly demonstrated that superconducting circuits with certain parameters can be in quantum superposition of macroscopically distinct states. This has important implications, for instance, for the quantum measurement theory, for the description of the interaction between light and matter as well as for implementation of new generation of quantum limited detectors and quantum information processing devices. Here both – basic ideas and practical realization of superconducting qubits – are discussed. [Copyright &y& Elsevier]