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In this paper, a three-phase multilevel power factor correction rectifier using the hybrid switched-capacitor concept is proposed. The converter is suitable for high-voltage-gain applications from conventional three-phase low-voltage sources. The three-level voltage operation reduces the weight and bulk of the magnetic devices. The main advantages of the proposed converter are low number of active switches, high voltage gain, sinusoidal currents, low voltage stress across all components, and simple control. Both steady-state and dynamic analyses are investigated. Experimental results for a 7500-W/220-V-to-1600-V laboratory prototype with maximum efficiency of 97.78% are presented and discussed. [ABSTRACT FROM AUTHOR]

This paper proposes a modular isolated dc–dc converter, based on the input-series and output-series association of the full-bridge PWM dc–dc converter with capacitive filter. The main attribute of the proposed architecture is its ability to provide self-balance of the input and output voltages across the individual converters, without voltage loop control scheme, both in the steady-state and transient operations. Circuit operation, theoretical analysis, and modeling are included in this paper, along with experimental results taken from a laboratory prototype with four modules, 1600-Vdc total input voltage, 1600-Vdc total output voltage, 4-kW output power, and 40-kHz switching frequency. Possible applications include high-voltage power supplies, solid-state transformers, dc current distribution systems, and renewable electric energy systems. [ABSTRACT FROM PUBLISHER]

This paper proposes an isolated three-phase rectifier power-factor correction using two single-phase buck preregulators in continuous conduction mode. The use of the Scott transformer renders a simple and robust rectifier to operate with unity power factor. With only two active switches, the rectifier is able to generate symmetrical currents in the line and a regulated voltage output without any necessary synchronous switches. The proposed control technique with sinusoidal pulse width modulation uses a feedforward of the output inductor current and only one voltage control regulates the output. Complete simulation results under closed-loop operation are given and a 12-kW prototype has been implemented in the laboratory, which demonstrated to operate successfully with excellent performance, and thus can feasibly be implemented in higher power applications. [ABSTRACT FROM AUTHOR]

A three-phase dc–dc converter based on the three-phase neutral point clamped (NPC) commutation cell is proposed, which is intended for use in applications where the energy from a medium dc bus voltage needs to be processed. In this paper, all six continuous conduction modes (CCMs) are described, presenting the main waveforms and equations. For the discontinuous conduction modes the main equations are also provided for a complete converter characterization. Experimental results for a 10 kW, 800 V input voltage, 200 V output voltage, 91% efficiency, 40 kHz laboratory prototype are also presented to verify the theoretical analysis carried out. [ABSTRACT FROM AUTHOR]

Deals with a study that introduced the Flying-Capacitor ZVS pulse width modulation 1.5 kilowatts direct current-to-direct current converter. Information on the circuit and principle operation of the converter; Relevant analysis results; Design procedure and example; Experimental results.

Presents information on a study which proposed a zero-voltage switching (ZVS) scheme for a three-level capacitor clamping inverter based on a true pulsewidth modulation pole. Main circuit modulation strategy and proposed ZVS topology; Theoretical analysis of the commutation process; Design methodology of the auxiliary circuit; Conclusions.

Presents information on a study which focused on a novel single-phase power-factor pulsewidth-modulated boost rectifier. Novel topology and principle of operation; Analysis of commutation; Conclusions.

Presents information on a study which analyzed a proposed high-power-factor three-phase alternating current (AC)-direct current (DC) converter composed of a line interphase transformer (LIT) and two three-phase rectifiers and pulsewidth modulation dc-dc boost converter. Description of the proposed circuit; Principle of operation; Data analysis; Results.

Presents a paper which discusses pulsewidth modulated (PWM) converters which feature soft commutation of semiconductors at zero current in transistors and zero voltage in rectifiers. Similar characteristics of converters and hard-switching PWM; Suitability of converters for high power applications using insulated gate bipolar transitors; Other advantages of a zero-current switching-PWM boost converter.

Introduces a family of zero-voltage switching (ZVS) pulse-width modulation (PWM) active-clamping dc-to-dc boost converters. Objectives of the technique; Description of the experimental results of the clamped mode ZVS-PWM boost converter; Statistical information on the converters.

This paper describes a theoretical and experimental study on a control strategy for the parallel operation of single-phase voltage source inverters (VSI), to be applied to uninterruptible power supply. The control system for each inverter consists of two main loops, which both use instantaneous values. The first (parallelism control) employs the feedback of the inductor current from the output filter to modify the input voltage of the same filter and, therefore, to control the power flow of each inverter to the load. Additionally, the second loop (voltage control) is responsible for controlling the output voltage of the LC filter, which coincides with the output voltage of the VSI. Due to the fact that there is no exchange of information among the VSIs regarding their operation points, it is easier to obtain redundant systems. Furthermore, the connection (or disconnection) of inverters in a parallel arrangement is carried out directly, without connection impedance, and can occur at any operation point of the system. The proposed control strategy ensures the proper sharing of the load current and avoids current circulation among the inverters during transient and steady-state operation. Moreover, its design and implementation are very simple. The control technique was verified through experimental results with a maximum load of 10 kVA supplied by three parallel-connected inverters. [ABSTRACT FROM PUBLISHER]

This paper presents a zero-voltage (pulsewidth modulation) half-bridge inverter with active voltage clamping using only a single auxiliary switch. The structure is particularly simple and robust. It is very attractive for single-phase high-power applications. Switching losses are reduced due to implementation of the simple active snubber circuit that provides zero-voltage-switching conditions for all switches, which includes the auxiliary one. Its main features are simple modulation strategy, robustness, low weight and volume, low harmonic distortion of the output current, and high efficiency. The principle of operation for steady-state conditions, mathematical analysis, and experimental results from a laboratory prototype are presented. [ABSTRACT FROM AUTHOR]

The focus of this paper is the study of direct alternating-current (ac)–ac converters, beginning by buck, half-bridge, full-bridge, and push–pull converters. From the basic converters, we apply a simple methodology to make the use of switches in commercial configurations possible. Following that, eight voltage restorers supplied either on the line side or on the load side are proposed. A comparative evaluation of these topologies concerning implementation, complexity, and component effort is presented. It is notable that some of the studied topologies are known in the literature and others are new. For one of the presented topologies, the design of a 3-kVA voltage restorer is developed, and experimental results are shown, certifying the correct operation of the drive strategy used. [ABSTRACT FROM AUTHOR]