Voltage regulator

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

Compensation voltage control in dynamic voltage restorers by use of feed forward and state feedback scheme

Abstract: This paper discusses the control of the compensation voltages in dynamic voltage restorers (DVR). It first analyzes the power circuit of a DVR system in order to come up with appropriate control limitations and control targets for the compensation voltage control. Based on this power stage analysis, a combined feed forward and state feedback control structure for the compensation voltages of DVRs is developed. This paper also discusses the time delay problems inherent in the digital control system of a DVR. Digital control systems normally have control delay from the sampling period, the switching frequency of the inverter, the sensor transmission time, etc. The control delay increases the dimension of the system transfer function. This makes the control system more unstable. This paper analyzes the control performance related with the control delay, closed loop damping factor, and the output filter parameters in DVR systems. Based on the control system analysis, design guidelines are proposed for the control gains and the inverter switching frequency of DVRs. The proposed theory is verified by an experimental DVR system with a full digital controller.

Uninterruptible power supply with improved output regulation

Abstract: A microprocessor based uninterruptible power supply generates an AC electrical output power from an AC input source when the AC input source is within settable voltage limits and from an auxiliary source of DC power when the AC input source is outside said the voltage limits. The microprocessor provides monitoring of the AC input voltage to determine its amplitude and frequency, and uses this information to set the magnitude and frequency of the AC output voltage and to select the source of the AC output power. A power factor improvement circuit boosts the selected source to a high DC voltage which is inverted by a chopper circuit to produce a high frequency AC voltage is rectified and sent to a PWM inverter to produce the AC output power. An average current feedback loop provides the output voltage regulation and utilizes current limiting to provide output current limiting for protection against short circuits and overloads. A voltage phase relationship is maintained between the AC input power and AC output power to eliminate voltage and current transients at transfer times between the AC and DC input sources. A serial data communications port sends data sent over a network that includes signals indicative of the status of the uninterruptible power supply and receives data from the network for controlling operation of the uninterruptible power supply.

Parallel Three-Phase Inverters: Optimal PWM Method for Flux Reduction in Intercell Transformers

Abstract: Parallel multilevel converters are now widely used in the industry, particularly in high-current applications such as voltage regulator modules. The reduction of the output current ripple and the increase of its frequency are possible due to the use of interleaving techniques and, as a consequence, the filters associated with the converter may be reduced. The current ripple reduction in each commutation cell of a parallel converter is possible by the use of intercell transformers (ICT). The design of such a special magnetic component depends very strongly on the magnetic flux flowing through their cores. In three-phase systems coupled by ICTs, the injection of zero-sequence signals in the output voltage reference changes this flux. The aim of this paper is to explain the influence of the most popular pulse width modulation (PWM) methods regarding the ICT flux for applications to three-phase loads. An optimal PWM method that minimizes the size of the ICT design is developed. Experimental results verify the analysis presented in this paper and validate the flux reduction provided by the developed optimal zero-sequence signals.

Resonant free power network design using extended adaptive voltage positioning (EAVP) methodology

Abstract: Extended adaptive voltage positioning (EAVP) is a new robust methodology for the design and analysis of a low impedance resonant free power delivery network, which utilizes and extends the theory of adaptive voltage positioning (AVP) that is commonly used in voltage regulator module (VRM) design and operation. Using EAVP, uncertainties in design guardband noise budget can be removed, resulting in significant performance bin-split improvement and cost reduction. Design optimization of decoupling capacitors with EAVP will be illustrated by using both time and frequency domain analysis.

Linear voltage regulator using adaptive biasing

Abstract: A linear voltage regulator, such as a low-dropout regulator, supplies power to one or more digital circuits within a computer system. The low-dropout regulator provides a substantially constant output voltage independent of loading conditions. The low-dropout regulator is biased at a relatively low operating current for steady-state operation to improve power efficiency of the low-dropout regulator. During a loading condition change, an adaptive biasing circuit senses the loading condition change and provides additional biasing current to momentarily increase the operating current of the low-dropout regulator to improve transient response.