Showing papers on "Buck converter published in 1984"

Implantable physiological power supply with PVDF film

Abstract: A fraction of the energy expenditure for respiration can be converted into electric power to supply implants which require a permanent power source. Toward this goal the relative motion of the ribs can be used for periodical stretching of a converter. A miniaturized prototype with solid electrical and mechanical contacts has been designed. We describe here the physical characteristics of the device and present the first results of an animal experiment. With improved PVDF films, a power converter with a film mass of a few g could supply implanted electric systems with a power of 1 mW.

New Solar Cell Power Supply System Using a Boost Type Bidirectinal DC-DC Converter

Abstract: A new solar cell power supply system is presented, in which the boost type bidirectional dc-dc converter and the simple control circuit with a small monitor solar cell are employed to track the maximum power point of the solar array. It is confirmed by the experiment that the new system has sufficiently precise tracking operation performance and satisfactorily high power efficiency. Also, a comparison of the power efficiencies is made theoretically, as well as experimentally, on the new and the conventional solar cell power supply systems. As a result, it is revealed that the new system is superior to the conventional one in the power efficiency.

Stability Analysis of a Buck Regulator Employing Input Filter Compensation

Abstract: The interaction between the input filter and the regulator often causes serious degradation of performance. The reduction in loop gain due to input filter interaction can result in system instability. An exact stability analysis of the buck regulator system is presented. The input filter parameter values are varied and system instability is predicted for the case without feedforward. The eigenvalues of the system can be brought back into the unit circle and the system thus stabilized with the addition of the feedforward loop. Measurements made for the cases with and without feedforward confirm the analytical prediction.

Fuel injection apparatus employing electric power converter

Abstract: Fuel injection apparatus including a power converter for generating a stable, high voltage DC signal for powering the fuel injectors. The power converter is connected to a voltage source such as a vehicle battery. The power converter includes a DC-DC converter and a feedback-stabilized converter control circuit. The converter control circuit adjusts the operation of the DC-DC converter in a direction to counteract changes in output voltage caused by battery voltage variations. The high voltage DC signal is applied to each injector through one or more solid state switches. Since the signal used to power the fuel injectors is substantially constant regardless of normal battery voltage variations, the injector pull-in time is substantially constant. Moreover, the use of a high voltage power signal enables low current injectors to be used. The low injector current results in low power dissipation by the solid state switches which operate the injectors. The output voltage generated by the converter is also used to bootstrap the power signal applied to the converter control circuit.

A fast time domain digital simulation technique for power converters - Application to a buck converter with feedforward compensation

Abstract: Small-signal analysis was performed earlier to demonstrate the marked improvement of dynamic properties and stability margins of a switching regulator employing a novel feedforward input filter compensation scheme. A large-signal nonlinear recurrent time domain model is presented for the converter to analyze the transient response due to a step input change with and without the presence of the proposed feedforward loop. The results are verified with experimental data.

Hybrid electric power generating system

Abstract: A hybrid power system comprises a first energy converter operating on a closed Rankine cycle and including a vapor generator for vaporizing an organic working fluid in response to heat furnished from a heat source associated with a vapor generator, a turbo-generator responsive to vaporized working fluid for generating electrical power, and a condenser responsive to vapor exhausted from the turbo-generator for converting said vapor to a condensed liquid which is returned to the vapor generator. The system also includes a second energy converter including a thermo-electric generator having a junction, a heat source for heating said junction whereby said thermo-electric generator generates electrical power, and a heat pipe for conveying heat from said last mentioned heat source to the vapor generator of the first energy converter and to the junction.

A fast time domain digital simulation technique for power converters: Application to a buck converter with feedforward compensation

Abstract: Small signal analysis was performed earlier to demonstrate the marked improvement of dynamic properties and stability margins of a switching regulator employing a novel feedforward input filter compensation scheme. A large signal nonlinear recurrent time domain model is presented for the converter to analyse the transient response due to a step input change with and without the presence of the proposed feedforward loop. The results are verified with experimental data.

Design and operating experience of an ac-dc power converter for a superconducting magnetic energy storage unit

Abstract: The design philosophy and the operating behavior of a 5.5 kA, +-2.5 kV converter, being the electrical interface between a high voltage transmission system and a 30 MJ superconducting coil, are documented in this paper. Converter short circuit tests, load tests under various control conditions, dc breaker tests for magnet current interruption, and converter failure modes are described.

High-speed feedback circuit

Abstract: A high-speed feedback circuit for use with, particularly, a buck or buck derived regulator (power processor). The circuit employs a voltage developed by the regulator after the switch and before the filter. From the voltage a current is developed which is combined with (subtracted from) a reference current. The combined current is integrated in a capacitor to develop a voltage used to drive the switch.

Digital-to-analog converter biasing control circuit

Abstract: A device for controlling the output voltage range of a digital-to-analog (D/A) converter of the type wherein the converter output voltage range is proportional to the magnitude of an applied bias current. The device comprises means to sample and store a selected converter output voltage, means to produce a variable current of magnitude proportional to the stored converter output voltage, and a source of constant current. The constant current and the variable current are summed and applied to the converter as the bias current. The converter output voltage range is dependent on the variable portion of the applied bias current which is in turn dependent on the stored, selected converter output voltage.

DC-DC converter having feedback type switching voltage converting circuit

Abstract: A DC-DC converter having a high conversion efficiency and stable output voltage. A constant current supply circuit, located between the output terminals of the converter, make it possible for the source current to decrease as a function of battery output voltage, resulting in lower current requirements for a lower required voltage boost and hence increased efficiency.

Applications of Magnetics to Problems in Switched-Mode Power Conversion

Abstract: Two topics are presented which advance the use of magnetic devices in switched-mode power converters. Part I discusses a novel method of detecting impending saturation of magnetic materials. The technique exploits the interaction of perpendicular magnetic fields to provide a simple, direct and continuous measure of the increasing nonlinearity of the material without any elaborate unconventional devices or complex electronic circuitry. Theoretical foundations and applications to ferrite cores in switching converters are given. Specific practical hardware examples are described including magnetics for a 4-kilowatt push-pull buck converter. Part II presents a discussion of the analysis of zero ripple integrated magnetic structures. These complex devices are of great interest in the field of switched mode power conversion because they have the ability to exclude ac currents from some of their windings when they are excited by ac voltages. A thorough analysis is carried out to establish which of the many characteristic parameters of these devices are responsible for the unusual zero ripple behavior. Practical methods of modelling and analysis are developed by which a designer can quickly determine the conditions required for zero ripple. Equivalent electric circuit models are given to aid in the electrical design of converters and to support the simple physical explanations of the observed phenomena including the effects of parasitic quantities. A number of experiments confirm the validity of the models.

Controlled parallel converter plant

Abstract: The electrical converter or inverter plant comprises several converter modules arranged in parallel between a power supplying line and a power consuming line. Each converter module includes a power converting unit being controlled by a control circuit which monitors the current and the voltage applied from the module itself to the load line. All functions of the plant are completely distributed among the converter modules so that no central arrangement exists. To coordinate the operation of the different modules there is provided one common current (voltage) balance bus to which all the control circuits are connected. The arrangement is constructed so that the voltage on the common current (voltage) balance bus shall be proportional to the current (voltage) provided to the load line from the module which produces the largest load current (voltage). This is obtained in a simple manner by connecting each control circuit with the common balance bus via an idealized diode.

The development of novel linear air dampers for use in sea-wave energy converter model tests

Abstract: amount of energy from the incident waves. In the particular sea-wave energy converter, the CLAM, studied by the authors, the energy in the waves is used to develop a reversing air flow within the device. The prime mover is the Wells turbine which, at constant speed, exhibits linear damping and also rectifies the reversing air flow. At t mode scale it is necessary to simulate the turbine for reasons of cost and the difficulties of model turbine performance and control. Conventional laminar-flow devices are inapproppriate due to their resultant size andfragility. Variable-area orifices

Electronically switched power supply with transformer choke

Abstract: The present invention relates to an electronic switching power supply for supplying power to an electrical load of AC or DC voltage sources of different voltage level to a buck converter. The buck converter comprises a series-connected with the switching path of a voltage applied to the input of the switching transistor throttle, one on the connection of the switching path of the switching transistor to the diode and a choke connected on the output side connected in parallel with the capacitor consumption. In the connection of the switching path of the switching transistor with the throttle, a first resistor is connected, to which a series circuit of a first zener diode is connected in parallel with the base-emitter path of a second transistor whose collector is connected to the base of the switching transistor. A magnetically coupled with the throttle feedback winding and the series circuit of a third capacitor and a fifth resistor, a feedback is provided to the base of the switching transistor. The electronic switching power supply provides a constant output voltage and fluctuating input voltage and an oscillation of the buck converter even under heavy load.

Ac-harmonics of power converter loads and the distortion of power system voltages

Abstract: Calculation of dynamic effects of power converter loads in the frequency domain is suggested. In this case the converter loads must be simulated by their frequency spectrum which is dependent on the actual operation mode of the converter load and on the feeding ac-voltage frequency spectrum. The dynamic effects on the feeding network can be reduced not only by means of compensation equipment but also by an optimal on-line-control of the power converter loads' operation. An optimizing method based on the maximum principle of Pontrjagin is described.