Showing papers on "Buck–boost converter published in 1977"

A new optimum topology switching DC-to-DC converter

Abstract: A novel switching dc-to-dc converter is presented, which has the same general conversion property (increase or decrease of the input dc voltage) as does the conventional buck-boost converter, and which offers through its new optimum topology higher efficiency, lower output voltage ripple, reduced EMI, smaller size and weight, and excellent dynamics response. One of its most significant advantages is that both input and output current are not pulsating but are continuous (essentially dc with small superimposed switching current ripple), this resulting in a close approximation to the ideal physically nonrealizable dc-to-dc transformer. The converter retains the simplest possible structure with the minimum number of components which, when interconnected in its optimum topology, yield the maximum performance. The new converter is extensively experimentally verified, and both the steady state (dc) and the dynamic (ac) theoretical model are correlated well with theexperimental data. both theoretical and experimental comparisons with the conventional buck-boost converter, to which an input filter has been added, demonstrate the significant advantages of the new optimum topology switching dc-to-dc converter.

High voltage single-ended DC-DC converter

Abstract: A new energy transfer system is evaluated for application in a 130 watt, l800 volt dc to dc converter. The single-ended half-wave transformer-coupled converter provides high efficiency (82%) with a low component count in the power train, resulting in a 25% cost reduction relative to a push-pull pulse-width controlled converter.

Cross regulation in an energy-storage DC-to-DC converter with two regulated outputs

Abstract: A model of a two-output voltage step-up/current step-up dc-to-dc converter is presented which demonstrates how the leakage flux associated with the energy-storage transformer affects cross regulation. First, expressions are derived which show the strong influence that leakage flux has on the secondary current waveforms. Then, after imposing steady-state constraints on the two equations describing the secondary current waveshapes, the cross regulation performance of the converter can be predicted. A comparison of predicted and observed results suggests that this model can be a useful tool for understanding converter cross regulation performance as well as for guiding the design of the energy-storage transformer in a multiple-output converter.

Spark plug igniter comprising a dc-dc converter

Abstract: A spark plug igniter with an auxiliary power source, in which the auxiliary power source is a DC-DC converter including a feedback loop. A high voltage induced in a secondary winding of an ignition coil and a DC voltage generated by the converter are additionally supplied in the same polarity to a spark discharge gap. The feedback loop of the DC-DC converter comprises a feedback winding, a rectifier connected to the feedback winding through a reactance element, and means for connecting the DC output of the rectifier in series to the DC power source of the converter in the same polarity.

A general linear continuous model for design of power conditioning units at fixed and free running frequency

Abstract: A linear continuous low frequency small signal model, valid for all types of converters (boost,buck, buck boost), both in heavy and light modes, is presented in this paper. Its interesting characteristics are that it is valid for free running as well as for fixed frequency converters and that it allows easily to take into account both input and output filters. Thanks to its modularity and its simple general form, it gives a strong insight into the influence of various parameters. (such as input filters) on performance dynamics and into the design of efficient control loops. Finally, a computer program, using state analysis, has been developed allowing the automatic performance analysis of complete controlled converters.

DC to DC converter with regulated input impedance

Abstract: A converter designed to be powered by a constant current and variable voltage source such as a coaxial cable of variable length includes regulation circuitry to regulate the input voltage of the converter. In particular, the switching device of a single-ended converter is pulse width modulated to regulate the input impedance and hence the input voltage of the converter to permit its efficient operation at varying cable lengths.

Method and system of controlling high voltage direct current power transmission plants

Abstract: In a method and system for controlling high voltage direct current power transmission plants, the delay angle for the each converter is calculated directly by a calculating arrangement, which is provided for controlling all converters totally, from data set by an operator and data transmitted by suitable sending-receiving apparatus from each converter. Each converter receives the delay angle signal by suitable sending-receiving apparatus from the calculating arrangement and operates in accordance with the received delay angle value. The delay angle value is given the following equation. ##EQU1## where α is a delay angle value. E is either a measured or calculated A.C. voltage, and if it is a measured voltage, it is the voltage from an A.C. system to which each converter is connected, V is either a set or calculated D.C. voltage, I d is either a set or calculated D.C. current and X is a converter commutation reactance.

Converter protection circuit operative to limit and counteract transformer saturation

Abstract: Primary and secondary currents of a converter transformer in a double-ended converter are continuously monitored to detect the onset of saturation in the magnetic core of the transformer. When the onset condition is detected, the conductive roles of the oppositely phased switching transistors in the converter are reversed to limit and counteract the onset of saturation in the magnetic core of the transformer.

Static Leonard system

Abstract: The disclosed Leonard type elevator system comprises a reversible converter for controllably driving a DC motor, and an AC voltage detector and a DC voltage detector connected to the AC and DC sides of the converter respectively for detecting the voltages developed on the respective sides of the converter. When a difference in detected voltage between the two detectors exceeds a predetermined magnitude due to a decrease in the AC source voltage, a comparator produces an output serving to disconnect the DC motor from the converter. Also the comparator may produce such an output when the converter receives regenerative power from the DC motor.

Line Current Waveforms and Harmonics for a Large Multiphase Thyristor Converter System

Abstract: Actual operating conditions of a large 18-phase rectifier group, which is one-half of a 36-phase system, are examined. Harmonic analysis of the actual line currents for this large thyristor converter system is performed. These results are compared with the idealized diode converter.

Sine-to-square wave converter

Abstract: A sine-to-square wave converter circuit utilizes a programmable unijunction transistor (PUT).

A Frequency to Voltage Converter for Use as a Speed Transducer

Abstract: In this paper a frequency-to-voltage converter is proposed for use as a speed transducer over a 100:1 range. It aims to keep to a minimum the number of pulses per revolution of the opto-electrical transducer required whilst also minimising the output voltage ripple content and giving an adequate speed of response. It operates on the basis of a phase-locked loop giving a modulation of constant mark-space ratio over the frequency range. Mathematical models of the converter are derived to analyse and predict its dynamic performance and the behaviour of a prototype practical circuit is examined.

Transistor oscillator power converter

Abstract: The converter includes a transistor, a transformer having a ferromagnetic core, tuning capacity, and rectification of high frequency oscillations which occur in the converter for producing a voltage for an electrical load different in magnitude from the voltage of an electrical energy source from which the converter takes power. Load voltage and electrical energy source voltage may be direct current voltages or changing voltages. The converter operates to maintain the voltage across the load at a constant value independent of the resistance of the electrical load. The oscillations occur only when transistor bias current is provided, for example by bias current conduction through the load, in which case negligible power is taken from the electrical energy source by the converter when the load is disconnected. High frequency of oscillations in the converter provides certain advantages.

Microwave input circuit with parametric down converter

Abstract: A microwave input circuit including a parametric upper sideband down converter for receiving an input signal whose frequency is not much different from the intermediate frequency produced at the output of the down converter. The down converter may be either of the series type or of the parallel type and has its signal input directly connected to a microwave antenna and terminated by the real antenna resistance (Rg) or the real antenna conductance (Gg), respectively, at the input signal frequency (fs1). The parametric down converter comprises a cascade connection of a parametric down converter stage and a parametric up converter stage with both of said stages being of the series type or of the parallel type. The down converter stage is terminated at its image frequency (fsp) with a real resistance (Rsp) or a real conductance (Gsp), respectively, and satisfies the following relationship for a series type down converter: ##EQU1## WHERE Rs1 is the series resistance of the reactance diode in the down converter stage, or the following relationship for a parallel type down converter: ##EQU2## where GD1 is the conductance loss of the reactance diode in the down converter stage, due to Rs1.