Topic
Voltage regulator
About: Voltage regulator is a research topic. Over the lifetime, 33536 publications have been published within this topic receiving 350859 citations.
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Papers
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08 Oct 1995TL;DR: A new three phase to three-phase converter for AC motor drives is proposed that employs only eight switches and has the capability of delivering sinusoidal input currents with unity power factor and bidirectional power flow.
Abstract: A current-controlled VSI-PWM rectifier and inverter with capacitor DC link is regarded as one of the most important structures for three-phase to three-phase power conversion. This type of power converter normally requires twelve switches for the rectifier and an inverter composed of self turnoff switch such as a bipolar transistor or an IGBT with an anti-parallel diode. In this paper, a new three-phase to three-phase AC/AC power converter for AC motor drives is proposed. The proposed power converter employs only eight switches and has the capability of delivering sinusoidal input currents with unity power factor and bidirectional power flow. This paper describes the feasibility and the operational limitations of the proposed structure. A mathematical model of the system is derived using the generalized modulation theory and experimental results for steady-state and dynamic behavior are presented to verify the developed model.
253 citations
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20 Jun 2004TL;DR: In this paper, a new control method for the parallel operation of one or several inverters in an island grid or the mains is described, where the reference AC voltage source is synchronised with the grid, with a phase shift, depending on the difference between nominal and real grid frequency.
Abstract: In this paper, a new control method for the parallel operation of one or several inverters in an island grid or the mains is described. Frequency and voltage control, including mitigation of voltage harmonics, are achieved without the need for any common control circuitry or communication between the inverters. Each inverter supplies a current that is the result of the voltage difference between a reference AC voltage source and the grid voltage across a virtual impedance with real and/or imaginary parts. The reference AC voltage source is synchronised with the grid, with a phase shift, depending on the difference between nominal and real grid frequency. A detailed analysis show that this approach has superior behaviour in comparison with the existing droop control methods, considering the mitigation of voltage harmonics, short-circuit behaviour and, in the case of a non-negligible line resistance, the 'efficient' control of frequency and voltage. Experiments show the behaviour of the method for an inverter feeding a highly distorted load and during the connection of two parallel inverters in operation.
247 citations
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TL;DR: In this article, a novel current-sensing and current-sharing technique is proposed for interleaved quasisquare-wave (QSW) VRM topologies, which can be controlled simply in parallel converters without a current transformer and current sensing resistors.
Abstract: Future generations of microprocessors are expected to exhibit much heavier loads and much faster transient slew rates. Today's voltage regulator module (VRM) will need a large amount of extra decoupling and output filter capacitors to meet future requirements, which will basically make the existing VRM topologies impractical. As a candidate topology, the interleaved quasisquare-wave (QSW) VRM exhibits very good performance, such as a fast transient response and a very high power density. The difficulty with the application of the interleaved parallel technology is the current-sharing control. In this paper, a novel current-sensing and current-sharing technique is proposed. With this technique, current sharing can be controlled simply in parallel converters without a current transformer and current-sensing resistors. In addition, this technique can be easily integrated with an IC chip. The four-module paralleled QSW VRM is used to evaluate this technique. Experimental results verify that with this technique, the VRM has a high power density, high efficiency and a fast transient response. The concept of the current sharing technique is also generalized and extended.
247 citations
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TL;DR: In this article, several compensation strategies are examined, in terms of satisfying custom power while taking into consideration the capacity of the energy-storage device and the voltage injection constraint of the dynamic voltage restorer.
Abstract: Summary form only given, as follows. Voltage sags are one of the most important power quality problems challenging the utility industry. Voltage sags can be compensated for by voltage and power injection into the distribution system. By injecting voltage with a phase advance with respect to the sustained source-side voltage, reactive power can be utilized to help voltage restoration. Hence, the consumption of real power, from the perspective of the energy supply device, can be reduced. This energy-saving voltage injection comes at the expense of an increased voltage injection magnitude, load power swing phase shift and discontinuity of voltage wave-shape. For this reason, several proposed compensation strategies are examined, in term of satisfying custom power while taking into consideration the capacity of the energy-storage device and the voltage injection constraint of the dynamic voltage restorer. Numerical examples are included to illustrate the efficacy of the proposed control strategies.
247 citations
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TL;DR: A new step-up DC-to-DC power converter with high power density is presented, which contains no inductors or transformers and features high efficiency for this class of powers, small output voltage ripple, continuous input current, low weight and small size.
Abstract: A new step-up DC-to-DC power converter with high power density is presented. It contains no inductors or transformers. The controlled energy transfer from an unregulated voltage source to a regulated output voltage is realized through a switched-capacitor circuit. The operation of the switches in the power stage is dictated by a PWM-type feedback circuit. The new regulator is simulated by using an averaged state-space approach. The transient and steady-state waveforms, as well as the AC small-signal input-to-output and control-to-output transfer functions are obtained by both simulation and experiments. The power supply, implemented for a nominal power of 15 W, and input-to-output voltage ratio of 5/12, features high efficiency for this class of powers, small output voltage ripple, continuous input current, low weight and small size. >
244 citations