Showing papers on "Forward 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.

DC-to-DC switching converter

Abstract: A dc-to-dc converter having nonpulsating input and output current uses two inductances, one in series with the input source, the other in series with the output load. An electrical energy transferring device with storage, namely storage capacitance, is used with suitable switching means between the inductances to DC level conversion. For isolation between the source and load, the capacitance may be divided into two capacitors coupled by a transformer, and for reducing ripple, the inductances may be coupled. With proper design of the coupling between the inductances, the current ripple can be reduced to zero at either the input or the output, or the reduction achievable in that way may be divided between the input and output.

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.

DC signaling circuit for use in conjunction with isolation transformers

Abstract: The present invention relates to a DC signaling circuit operatively associated with a communication system having an isolation transformer interconnected between a central communication exchange center and a station site such as a power substation or generating plant where high voltage potential exists. The isolation transformer provides protection from fault conditions that could apply hazardous voltage to a cable pair entering the station. Because of the presence of the isolation transformer, there is no direct path for DC signal functions to pass from the station to the central communication exchange center. Thus, the DC signaling circuit of the present invention is designed to simulate and transfer the simulated DC signals across the isolation transformer to a line side of the communication system leading to the central communication exchange center. DC signals and logic information generated by a signal source such as a telephone on the station side of the isolation transformer can thusly be effectively transferred across the isolation transformer exactly as generated and in a clear and undistorted manner due, at least in part, to provisions in the DC circuit that shunt the windings of the isolation transformer during time intervals when DC signals are generated and communicated to the line side of said communication system.

DC voltage converter and shock-type high voltage utilization devices

Abstract: A DC voltage converter includes an oscillator that converts a DC battery voltage to an oscillating voltage, a low voltage transformer that increases the oscillating voltage to a higher oscillating voltage, and a voltage rectifying-capacitor charging network or multiplier that increases the higher oscillating voltage to yet a higher DC voltage at an output terminal for DC high voltage utilization devices and the like. An electric control switch is selectively actuated by the user to apply the battery voltage to the oscillator, resulting in the generation of the stepped-up DC voltage at an output terminal. Another DC voltage converter has an electronic switching circuit that automatically turns the oscillator on and off and a load capacitor across the electrodes that is charged and discharged to provide a shocking voltage. Utilization devices for the voltage developed by the converter shown are a miniature animal training device and a cattle prod device. The miniature animal training device has a pair of outwardly projecting electrodes mounted on a side at one end of the housing that is sized and shaped to fit within and conform to the palm of a hand. The cattle prod device has a pair of electrodes fixedly mounted on the end of a housing assembly made up of telescoping tubular housing sections arranged for relative axial movement whereby the pressing of the electrodes against an object to be shocked actuates the electric control switch and causes a shock of the object. The housing assembly is releasably supported by a rigid handle or an extensible handle assembly.

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.

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.

Voltage control circuit for a DC-to-DC convertor

Abstract: A DC voltage convertor utilizes a switching transistor for switching the primary of a power transformer inserted in the emitter-collector circuit of the transistor, the base of the transistor is connected to the secondary of a control transformer which has its primary connected in series with the primary of the power transformer. A further secondary winding on the control transformer is connected to a transistor control circuit, which is controlled by a voltage dependent on the output voltage of the converter, provides voltage stabilization without galvanic connection between the primary and secondary sides.

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.

New DC-DC converters with an energy storage reactor

Abstract: New DC-DC power converters with an energy storage reactor are presented. In the conventional converter circuits of an energy storage reactor, there is an extraordinary increase of the output voltage due to the excess magnetic energy, when the reactor current becomes discontinuous for the light-load. This phenomenon can be removed by making use of a dummy load or a reactor of sufficiently large inductance. However, the use of the dummy load makes the efficiency poorer and the size as well as the weight becomes larger if the inductance of the reactor is increased. In the converter circuits presented, the excess magnetic energy, which is stored in the reactor and undissipated in the load circuit, can be recovered to the input power source through the additional transistor and diode. With these converter circuits, the dummy load can be removed for any load condition and further the inductance of the reactor can be made smaller.

Power converter control system

Abstract: A power converter control system for use with a power converter of the type which comprises a plurality of cascade-connected converter units of which at least one converter unit is subjected to continuous control of its conduction phase angle and the remaining converter units are subjected to on-off control of their conductivity is arranged to include a master controller for instructing the number of the converter units to be rendered operative, a reversible counter operative to change its content in response to a phase controlling command applied to the continuously controlled converter unit indicating a maximum or minimum conduction phase angle or delayed phase angle in conduction, a unit change control unit for producing unit changing operation signals to be applied to the respective converter units for controlling the operation of the same, by using one of the binary bits derived from the counter without modification and decoding the remaining bits, and a comparing and identifying circuit which compares the content of the reversible counter with the output of the master controller and causing the reversible counter to operate in response to the aforementioned phase control command until the content of the same becomes identical to the output of the master controller.

Stabilized DC power supply devices for providing a plurality of DC power outputs which are selectively consumed

Abstract: A stabilized DC power outputs supply devices for providing a plurality of DC power outputs which are selectively consumed, is provided by use of a single power control circuit. A plurality of DC power outputs are taken out from the single power control circuit through rectifier circuits and low-pass filter circuits. A voltage of each of the DC power outputs is sensed by a corresponding voltage sensing circuit and is compared with a corresponding reference voltage at a corresponding voltage comparing circuit. Detecting circuits for detecting one of the DC power outputs which is being consumed are provided to apply to a control signal generator the output of one of the comparing circuits which is corresponding to the DC power output detected by the detecting circuits. The control signal generator provides a control signal to the single power control circuit to stabilize the voltage of the DC output which is being consumed.

High frequency capacitor-diode voltage multiplier dc-dc converter development

Abstract: A power conditioner was developed which used a capacitor diode voltage multiplier to provide a high voltage without the use of a step-up transformer The power conditioner delivered 1200 Vdc at 100 watts and was operated from a 120 Vdc line The efficiency was in excess of 90 percent The component weight was 197 grams A modified boost-add circuit was used for the regulation A short circuit protection circuit was used which turns off the drive circuit upon a fault condition, and recovers within 5 ms after removal of the short High energy density polysulfone capacitors and high speed diodes were used in the multiplier circuit

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.

The Venerable Converter: A New Approach to Power Processing

Abstract: A regulating dc-to-dc converter is described which utilizes a new circuit configuration to achieve several desirable features including higher efficiency, a single circuit for regulation and conversion, minimized output filter requirements, and simplified control system applications. The dc operating characteristics are derived and the efficiency of the new converter is shown to compare favorably with the conventional boost regulator. An ac model is derived and a comparison is made between analytical and experimental results.

Push pull DC voltage converter - has energy recovery circuit and controller to increase keying ratio for low output

Abstract: A push-pull dc voltage converter has an energy recovery circuit with an inductance (L1) in the transformer (Tr) positive supply wire (+) and with a second inductance L2) tightly coupled with the first. One terminal of the second inductance is connected to the negative supply wire (-), and the other through a diode (D) in the forward direction, to the input terminal of the positive supply wire. A capacitor (C) is inserted between the two input terminals. A control circuit operates a control unit so that they keying ratio is increased when the output voltage falls, and vice-versa.

Schaltungsanordnung fuer geregelte gleichspannungsumrichter

Abstract: In the case of the circuit arrangement for the regulated DC/DC voltage converter, a clock transmitter (P) predetermines the maximum control range at a constant operating frequency. Said control range is determined from the minimum input voltage and the maximum load. A transformer is provided for potential isolation. Switching means (R3, C2, G3), for example auxiliary converters (HU, D3) are provided which vary the maximum control range continuously as a function of the input voltage (UE). This avoids saturation of the power transformer in the event of a load change.

Thyristor control method for thyristor AC-DC converter

Abstract: In an AC-DC converter for converting an AC power by a six-phase, half-wave or three-phase, full-wave back-to-back or anti-parallel connection thyristor bridge to a DC power for input to a load, while the current to the load is small, the converter is actuated as a converter of a three-phase, half-wave back-to-back connection bridge, thereby to enable an alternate supply of negative and positive currents to the load. Letting the output by the AC-DC converting operation of the three-phase, half-wave back-to-back connection bridge and the output by the other converting operation be identified as main and auxiliary outputs, respectively, as the load current increases, the auxiliary output is also supplied to the load.

Generation circuit for high voltage

Abstract: PURPOSE:To obtain the medium high voltage output stable independently of the variation in the load and the correction signal, by connecting the secondary coil of auxiliary transformer to the secondary coil of the flyback transformer and controlling the switching phase of the converter. CONSTITUTION:The horizontal output circuit is connected to the primary coil of the flyback transformer 1 and high voltage output is obtained at the secondary coil, and the auxiliary transformer 20 is placed and the secondary coil is connected to the secondary coil of the transformer 1. Futher, the converter 22 is connected to the primary coil, controlling the switching phase of the converter 22. Thus, stable medium and high output can be obtained independently of the variation of the load and the correction signal.

DC voltage converter overload protection - monitors AC pulse decay preventing chopping action until pulse decays to predetermined level

Abstract: The DC voltage converter employs a high frequency chopper stage and a secondary rectifier for changing the DC voltage. The chopper is protected against overloads by continuously monitoring the rate of decay of one of the critical parameters in the AC link, and inhibiting further choping action until it has decayed to below at set level. The parameters monitored in this way may be output transformer magnetisation, current in one of the transformer windings, voltage induced in a winding, or the change of current in a choke coil in series with the output. The output monitor acts on the chopper control circuit to modify operation.

Converter for dc transmission system

Abstract: PURPOSE: In transmission system where power from AC system is rectified for DC transmitted and inverted at receiving side, to perform continuous operation when fault occurred in AC system by installing sound phase detector in converter. COPYRIGHT: (C)1978,JPO&Japio

Protective relay means for ddc transmission line

Abstract: PURPOSE:To provide a protective relay means for protecting a d - c transmission line from grounding accident, and in which system for the purpose of detecting the grounding accident the quantity of information transmission between forward converter side reverse converter side is reduced.

Dc circuit breaker

Abstract: PURPOSE:To simplify structure by utilizing filtering capacitor and surge absorbing capacitor connected to the output of forward converter as aux capacitor of commutation circuit breaker when interrupting DC circuit breaker

Controller for dc transmission system

Abstract: PURPOSE:To prevent DC current interruption due to commutation failure of reverse converter, by limitting firing phase control range of the other forward converter when DC current in one DC transmission system changed abruptly.

Protection of power converter

Abstract: PURPOSE:In the power converter combining forward converter and reverse converter consisting of controlled rectifier, to send forth signals to lock the forced ignition circuit may permit the power converter to protect.

Selffexcited ac generator

Abstract: PURPOSE:In the system of the self-excited AC generator in which the excitation power is taken out from the armature winding of the generator and rectified by the semiconductor forward converter, and the DC output is supplied to the field winding, the sustained short-circuit current can be supplied even in the short-circuit of the load.

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.