Rectifier

About: Rectifier is a research topic. Over the lifetime, 35134 publications have been published within this topic receiving 267352 citations. The topic is also known as: one-way conductor.

Radio-frequency generator with automatic power control for radio-frequency surgery

Abstract: The invention describes a radio-frequency generator for radio-frequency surgery, with a power amplifier operating in switched mode, a modulation device for controlling the output, and a harmonics measuring device for measuring the harmonic frequencies of the generator frequency which are generated by the arc produced between the surgical probe and the tissue to be cut or to be coagulated. At the instant of start-up, the power amplifier is driven by an auxiliary oscillator. After the start-up, the drive of the power amplifier is switched over to selfexcitation, voltage feedback being selected when the load impedance exceeds a particular value, and current feedback when the load impedance falls below a certain value. During the feedback mode, the auxiliary generator is locked to the output frequency and output phase of the radio-frequency generator by means of a phase-locked loop. The harmonics measuring device contains a phase-controlled rectifier, the control signal of which is derived from the auxiliary generator. The advantage of such a generator lies in its low power dissipation, its high operational reliability and its low filtering complexity in the output circuit.

Quasi-Z-Source-Based Isolated DC/DC Converters for Distributed Power Generation

Abstract: This paper presents new step-up dc/dc converter topologies intended for distributed power generation systems. The topologies contain a voltage-fed quasi-Z-source inverter with continuous input current on the primary side, a single-phase isolation transformer, and a voltage doubler rectifier (VDR). To increase the power density of the converter, a three-phase auxiliary ac link (a three-phase inverter and a three-phase isolation transformer) and a three-phase VDR are proposed to be implemented. This paper describes the operation principles of the proposed topologies and analyzes the theoretical and experimental results.

Snubberless Bidirectional DC–DC Converter With New CLLC Resonant Tank Featuring Minimized Switching Loss

Abstract: A bidirectional DC-DC converter (BDC) with a new CLLC-type resonant tank, which features zero-voltage switching (ZVS) for the input inverting choppers and zero-current switching (ZCS) for the output rectifier switches, regardless of the direction of the power flow, is proposed in this paper. Possessing the very optimal ZVS +ZCS soft-switching feature, this proposed converter will have a minimized switching loss if all of the main switches are implemented with metal-oxide-semiconductor field-effect transistors, and thereby, the proposed converter is fully soft switched and totally snubberless. The detail operation principles, as well as the design considerations, are presented. The methodologies to develop a unidirectional ZVS+ZCS dc-dc converter for the corresponding pulsewidth modulation and frequency modulation converters are proposed. The approach on how to construct a fully soft-switched BDC has also been proposed and analyzed. Finally, a topology extension is made, and another fully soft-switched BDC is derived. A prototype, which interfaces the 400-48-V dc buses for the uninterrupted power supply system with a power rating of 500 VA, was developed to verify the validity and applicability of this proposed converter. The highest applicable conversion efficiencies for the bidirectional operational modes are exceeding 96%.

Dynamic Stability of a Microgrid With an Active Load

Abstract: Rectifiers and voltage regulators acting as constant power loads form an important part of a microgrid’s total load. In simplified form, they present a negative incremental resistance and beyond that, they have control loop dynamics in a similar frequency range to the inverters that may supply a microgrid. Either of these features may lead to a degradation of small-signal damping. It is known that droop control constants need to be chosen with regard to damping, even with simple impedance loads. Actively controlled rectifiers have been modeled in nonlinear state-space form, linearized around an operating point, and joined to network and inverter models. Participation analysis of the eigenvalues of the combined system identified that the low-frequency modes are associated with the voltage controller of the active rectifier and the droop controllers of the inverters. The analysis also reveals that when the active load dc voltage controller is designed with large gains, the voltage controller of the inverter becomes unstable. This dependence has been verified by observing the response of an experimental microgrid to step changes in power demand. Achieving a well-damped response with a conservative stability margin does not compromise normal active rectifier design, but notice should be taken of the inverter–rectifier interaction identified.

Solid state lamp

Abstract: An integrated circuit chip containing one or more light-emitting diodes is mounted within a light-diffusing encasement having a standard incandescent light bulb lamp base. The integrated circuit chip also contains a rectifier and voltage regulator circuit. The resulting solid state lamp may then be used to replace any standard incandescent light bulb, as it can be inserted in any existing standard A.C. or D.C. lamp sockets. The encasement may be a standard hollow light bulb, or, for maximum light diffusion, a solid transparent or translucent plastic in which the chip is embedded.