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The study of this article mainly focuses on the assessment and performance of current and voltage inverters in ozone generation, applying power density modulation (PDM) and typical operation. The topologies designed were a voltage-source full-bridge inverter (VSFBI), a current-source full-bridge inverter (CSFBI), and a CSFBI without considers the PDM. The inverters were analyzed and implemented considering an inductor–capacitor–capacitor (LCC) series–parallel resonant tank for the VSFBI and an LC parallel resonant tank for the CSFBI. The duty cycle impact (Dm) of the modulation signal was analyzed, and all inverters were compared. Based on the results, the decrease in Dm allows increasing the ozone generation because of avoiding the dissociation of the ozone molecules. The maximum concentration and efficacy presented by the VSFBI in ozone production were 620 gr/m3 and 0.155 gr/min. Also, the maximum electrical efficiency was 91%; it was presented by the CSFBI without PDM. [ABSTRACT FROM AUTHOR]

This paper presents an igniter circuit for high-intensity-discharge (HID) lamps based on an inverter and a resonant tank that has been adapted to stabilize inductively an HID lamp by means of applying low-frequency quasi-square waveforms to voltage and current in the lamp in order to reduce the presence of the acoustic resonances. With the proposed improvement, the igniter circuit performs three different functions: 1) the lamp ignition; 2) the arc stabilization; and 3) the acoustic resonances reduction. This proposal allows the use of fewer components, and less energy processing is minimized, so the resulting ballast is cheaper and more efficient than other ballast that avoids the acoustic resonances when they are working with square waveforms in the lamp voltage and current. The circuit was validated experimentally by using a 70 W conventional high-pressure sodium lamp, which is operated with a frequency of 2 kHz. The results were an electrical efficiency of 94%, a crest factor in the lamp current of 1.41, and it was not observed the presence of acoustic resonances. [ABSTRACT FROM AUTHOR]

This paper proposed the use of a ringer, a self-switched inductive storage system, for applications involving reluctance accelerators, a kind of electromagnetic launcher, and compatible with applications where portability is a requirement. There will be shown three different useful approximations for the analysis of the ringer, employed as a power source for a reluctance accelerator. First, it described the equations governing the que behavior of an ideal unloaded ringer, and then the equations for the ringer with an uncoupled inductive load, and ultimately a Lagrangian model for the ringer as an inductive power source for a reluctance accelerator, capable to make predictions about the currents through the circuits and the exit speed of the projectile for a given firing. The accuracy of the predictions made with the third approximation, the Lagrangian model, was tested experimentally. [ABSTRACT FROM AUTHOR]

The arrangement of the full-bridge, current-source inverter as a power supply for ozone generators providing high power factor (PF) and high electrical efficiency in a single stage is the main contribution of this paper. The corresponding design, simulation, and experimental results are presented. Also, the use of the current-fed, full-bridge resonant inverter for PF correction in ozone generation applications is discussed. The proposed power supply consists of an ac supply, a single rectifier bridge, an input inductor to the inverter, four switches, an LC parallel resonant tank, a resonant transformer, and a set of ozone generating cells. Experimental results with the proposed topology provided 96% for PF, 91% for electrical efficiency, and ozone production of 614 mgO3/min, satisfying the requirements of the standard 61000-3-2, class A. [ABSTRACT FROM AUTHOR]

In this paper, the analysis and design methodology of a high-frequency self-oscillating (SO) electronic ballast with lamp current control are presented. SO electronic ballasts have two important drawbacks: First, the lamp current varies according to the ac input voltage, causing undesired effects in the lamp brightness, and second, the design method lacks precision at very high frequency operation (greater than 200 kHz) mainly due to the Cgs parasitic capacitance. The ballast is modeled by using the descriptive function method and the extended Nyquist criterion; the model of the ballast includes a control circuit and takes into account the high-frequency effect of the MOSFET parasitic capacitance Cgs. Finally, experimental results of a 38-W SO electronic ballast prototype with lamp current control for high-intensity discharge lamps are presented to validate the analysis and the proposed methodology. The switching frequency is selected at 2 MHz in order to avoid the acoustic resonance problem. [ABSTRACT FROM AUTHOR]

In this paper, the dimming and frequency effects on stability, current crest factor (CCF), and power factor (PF) of high-intensity discharge lamps fed with square waveforms are experimentally evaluated. For this evaluation, the lamp was stabilized using resistances. The resistances were varied in function of the impedance of the lamp. The effects of dimming and frequency variation were observed for two types of lamps of different nominal powers. The results indicate the ranges in which the lamp is stable and the frontier values in which the lamp becomes unstable. The CCF and PF remain close to unity, and no acoustic resonances were observed during the applied tests. [ABSTRACT FROM AUTHOR]