Voltage regulator

About: Voltage regulator is a research topic. Over the lifetime, 33536 publications have been published within this topic receiving 350859 citations.

12-pulse rectifier for more electric aircraft applications

Abstract: A high power density 10 kW three-phase 12-pulse rectifier is analyzed for applications in future more electric aircrafts. The experimental results, which are in good accordance with the theory, show high efficiency and low input current harmonics for a wide operating range. Furthermore, two novel rectifier topologies, which are formed by combining the passive 12-pulse rectifier with a boost stage on the DC side are proposed. This allows to guarantee a constant output voltage and/or to overcome the problem of the dependency of output voltage on the mains voltage amplitude and output power level.

Slope compensation for switching regulator

Abstract: In one embodiment, a switching regulator comprises a control circuit that activates and deactivates at least one power switch to control a voltage of a switching node. The system also comprises an inductor that conducts a current from the switching node to an output to generate an output voltage. The system further comprises a PWM comparison circuit that controls an on-time and/or an off-time of the at least one power switch based on a comparison of a feedback voltage and a reference voltage. The PWM comparison circuit comprises a ramp signal generator configured to provide a ramp signal having a non-zero slope that is combined with either the feedback voltage or the reference voltage at a beginning of either the on-time or the off-time. The PWM comparison circuit can be further configured to set the slope of the ramp signal to zero during the off-time in a discontinuous conduction mode.

Sensorless Current Estimation and Sharing in Multiphase Buck Converters

Abstract: Virtually, all of the current-sensing methods for power converters presented to date rely on a priori knowledge of circuit parameters to ensure accurate current measurement. Also, the advent of digital control in low-cost high-volume applications-such as voltage regulator modules (VRMs) for computer microprocessors-has added the challenge and cost of analog-to-digital conversion to this task. This paper introduces a parameter-independent, sensorless current-sharing algorithm for multiphase power converters based on gradient estimation via low-frequency perturbation of the per-phase duty cycles, thus eliminating the need for current sensing. Measures of only the input and output voltages are required, so the analog-to-digital converter (ADC) and communication/interfacing overhead is low. The algorithm is demonstrated through both simulation and experimental implementation using a digitally controlled three-phase buck converter.

Integrated volt/VAr control in distribution systems

Abstract: The paper proposes new supervisory control schemes for integrated volt/VAr control at distribution substations and feeders. The new supervisory controller located at the substation coordinates the control of local regulating devices based on dynamically changing system conditions rather than local measurements. The supervisory scheme uses the measurements and communications between field devices in order to provide the coordination. Three different versions of this control scheme have been developed in order to accommodate for the varying amount of measurement and communication that may be available on a given system. Test results indicate that the new schemes better coordinate the control actions of the voltage regulator and capacitor banks and thus provide a more effective volt/VAr control.

Review of dynamic voltage restorer for power quality Improvement

Abstract: Power quality has always been important for customers, but with increasing applications of electronic loads and controllers sensitive to the power quality, the subject has attracted renewed interest in recent times. Power quality encompasses several aspects: harmonics, over voltage, flicker voltage sags and swells, interruptions etc., lasting only a few cycles can cause significant damage for a manufacturing process and computer hardware installations. Voltage source converter based dynamic voltage restorer (DVR) can be used effectively for mitigation of voltage sag and swells. This paper presents the operating principle, power circuit topologies, mathematical modeling, control philosophies and applications of DVR for power quality improvement along with systematic review of published literature.