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Renewable energy sources in DC microgrids require high-performance conversion systems to increase their capacity and reliability. Among other characteristics in conversion systems, the current ripple is a characteristic that must be considered since it affects the performance of PV panels and batteries. In this paper, a high-voltage-gain DC–DC boost converter for performing current ripple elimination that is based on a variable inductor is proposed. The topology is composed of a diode–capacitor voltage multiplier and a modified cascaded boost converter. To achieve voltage regulation, a reduced-order switched model is obtained considering the switched capacitor's dynamics. To address the inductance variation and external disturbances, the H ∞ control theory is adapted to systematically design a robust proportional–integral (PI) controller. Details of the working principles and the sizing of passive components are presented. The simulation and experimental results demonstrate that the input current ripple of the proposed converter can be removed in both transitory and steady states. [ABSTRACT FROM AUTHOR]

The active sound navigation and ranging (SONAR) transmission system emits acoustic pulses underwater using a wave generator, a SONAR power amplifier (SPA), and a projector. The acoustic pulse travel in the direction of the target and return as an echo to a hydrophone to learn the range or speed of the object. Often the same device is used as a hydrophone and a projector; in this context, it is known as a transducer. In order to obtain a maximum range of detection in the SONAR, it is desirable to generate the maximum amount of acoustic power until the point in which the echo can be detectable in an atmosphere with non-wished noise. Therefore, a high value of source level (SL) is required that depends largely on the value of electrical power applied to the transducer ( P e ). However, when trying to obtain the maximum range of detection in the SONAR system there are the following three peculiar limitations that affect performance: The cavitation, the reverberation, and the effect of interaction in the near field. In this paper, an experimental measurement methodology is presented to detect the cavitation effects in a tonpilz-type transducer for an active SONAR transmission system using a transducer as a projector and a calibrated hydrophone in a hydroacoustic tank by measuring the parameters of total harmonic distortion of the fundamental waveform (THD-F) of the generated acoustic pulse, transmitting voltage response (TVR) to characterize the system and sound pressure level (SPL) that indicates the intensity of sound at a given distance. Whereas the reverberation and the interaction effect in the near field are objects of other study cases. A 570.21 W and THD-F < 5 % switched-mode power amplifier (SMPA) prototype was developed to excite the electroacoustic transducer employing a full-bridge inverter (FBI) topology and a digital controller using a field-programmable gate array (FPGA) for unipolar sine pulse width modulation (SPWM) to generate a continuous wave (CW) acoustic pulse at a frequency 11.6 kHz. The results obtained show that from the level of P e = 196.05 W with the transducer at 1 m of depth, the value of THD-F increases significantly while the behavior of the TVR and SPL parameters is affected since it is not as expected and is attributed when cavitation occurs. [ABSTRACT FROM AUTHOR]

AC-DC conversion is required in many applications, and in some of them isolation is strictly required, certainly while maintaining characteristics such as a high power factor and low input current THD. In this paper, an AC-DC converter, comprising a full-bridge diode rectifier and a dual-active-bridge (DAB) converter, is utilized to fulfill these characteristics. The used modulation makes the converter behave as a resistive load, maintaining the output voltage constant while achieving a high power factor and low input current THD. The operation of the converter is simple, as only two voltage sensors are required, and no inner current loop is utilized. A low-power prototype was experimentally tested to corroborate the proposal. [ABSTRACT FROM AUTHOR]

DC/AC converters are widely used in several applications; traditionally, they can be classified in two types: the voltage-source inverters (VSIs) and the current-source inverters (CSIs). Their use depends on their application; however, some of them are common for both types of converters. Another possibility for the dc/ac conversion is the multilevel configuration, and the most analyzed is the VSI. In this paper, a different multilevel CSI is proposed: the paralleled configuration. To control the converter, a different sinusoidal pulse with modulation is employed; it consists of modifying the reference signal instead of using multiple carriers. Additionally, a balancing method for the inductor currents is given. The operation, analysis, and implementation are presented; moreover, simulation and experimental results are shown. [ABSTRACT FROM AUTHOR]

This paper describes a nonlinear model of highintensity discharge (HID) lamps based on electrical variables. The proposal, oriented to the engineering area, has a special application for the design of electronic ballast. Parameters are obtained from straightforward measurement of electrical variables as power, current, and voltage in the lamp. The lamp resistance is obtained as a function of electrical power; which is estimated from the Saha equation. This model, which can be simulated using software such as "Simulink" or "Pspice," takes into account some important dynamic behaviors of HID lamps, which are normally omitted in some other models suggested in literature nowadays. Experimental and simulation results are shown. [ABSTRACT FROM AUTHOR]

The boost inverter is a device that is able to generate a sinusoidal voltage with an amplitude larger than the input voltage. Based on the idea of indirectly controlling the output voltage through the inductor current, a dynamical sliding-mode controller for the boost inverter is proposed in this paper. Unlike the usual approach of generating a sinusoidal voltage in both capacitors of the boost inverter, the strategy proposed in this paper focuses on generating a sinusoidal voltage on the load despite the voltage form of both capacitors. A consequence of doing so is that only the desired output voltage is required as reference to implement the controller. Furthermore, it has a fast response, is robust under load and input voltage variations, and yet, is remarkably simple to implement. Although it is strongly nonlinear, it can be implemented using standard electronics circuitry and only needs voltage measurements. [ABSTRACT FROM AUTHOR]

An active current injection network for a three-phase rectifier is proposed. The proposed circuit uses three bidirectional switches operating at low frequency and a half-bridge inverter operating at high frequency. It also uses an inductor in order to make the current modulation. Because only 3.7% of the total power delivered to the load is processed by the injection network, the proposed converter offers high efficiency, and not only a high power factor is obtained but also the total harmonic distortion is reduced. Operation, analysis, simulation, and experimental results are shown in this paper. [ABSTRACT FROM AUTHOR]

This paper presents a novel ac uninterruptible-power-system (UPS) scheme with high power factor, which offers excellent characteristics such as sinusoidal input current, sinusoidal output voltage, fast regulation of the ac mains, galvanic isolation, and fast transient response. The proposed converter includes the offline-online concept, which avoids the continuous charging and discharging of the battery as it occurs in a typical online UPS. Analysis and design considerations, as well as simulation and experimental results, are given in this paper. [ABSTRACT FROM AUTHOR]

An uninterruptible power supply (UPS) with high power factor and two conversion stages is suggested. The double- conversion configuration has three stages, but normally, only two stages are operating at the same time. The first stage of the proposed scheme integrates the power-factor-correction stage and the battery charger of the double-conversion configuration, obtaining a two-stage UPS. The second stage is based on the theory of inverter with boosting capabilities. The battery set has not only been completely isolated, but it has also been charged with a small change at the controller set point; these particular characteristics facilitate the system maintenance and simplify its operation. Additionally, the battery-set voltage is low, reducing the weight and size. The converter operation, analysis, design, and experimental results are shown. The proposed UPS approach is practical in low-power applications (⩽ 500 W). [ABSTRACT FROM AUTHOR]

In recent years, several ac/dc converters have been presented in order to meet the power quality regulations, while maintaining the lowest number of components with the purpose of minimizing the cost and complexity; for this purpose the active input current shaping technique was proposed. In this paper a new active input current shaper (AICS) is presented. Differently from the traditional series AICS, the proposed scheme connects the auxiliary output of the main converter in parallel with the rectified ac mains instead of the series connection. The proposed parallel scheme demands a current with a low harmonic content where the standard specifications are fulfilled. The operation, simulation, and experimental results of the proposed scheme are presented. [ABSTRACT FROM AUTHOR]

Presents a simplified sinusoidal uninterruptible power supply (UPS) system with active power factor correction. Features of the proposed UPS system; Advantage of the system; Circuit operation of the proposed UPS system.