Showing papers on "Boost converter published in 1985"

Steady-State Analysis of the Series Resonant Converter

Abstract: The series resonant converter is analyzed in steady state, and for constant switching frequency the output current and voltage characteristics are found to be ellipses. The converter operating point can then be easily obtained by superimposing a load line on these elliptical characteristics. Peak resonant capacitor voltage and inductor current are also plotted in the output plane and are dependent to first order only on output current. When peak voltage and current are plotted in this manner, the dependence of component stresses on operating point is clearly revealed. The output characteristics are modified to include the effect of transistor and diode voltage drops, and experimental verification is presented.

Integrated circuit for controlling power converter by frequency modulation and pulse width modulation

Abstract: An integrated circuit contains the gate drivers and the control components for constructing a DC power supply in any of the most popular converter topologies. Multi-function elements in the control circuit minimize the area of the chip. The integrated circuit drives both the upper and lower switches of a half-bridge converter and separately regulates two power supply output voltages, one by pulse width modulation and the other by frequency modulation.

A Novel Sinewave in AC to DC Converter with High-Frequency Transformer Isolation

Abstract: A novel Switch-Mode-Rectifier (SMR) structure is proposed and analyzed in this paper The proposed converter structure employs a high-frequency sine PWM cycloconverter to provide high-frequency ohmic isolation between the source and the load Furthermore, it draws high-quality current from the ac source thus requiring only small input reactive components Consequently, the proposed converter structure exhibits high power density and has low implementation cost

Active power conditioner system

Abstract: At least two active conditioners are connected in series with a common DC source, and are mounted as a unit between two pairs of AC terminals to act either as a tie-in link between two AC power sources, as a buck/boost regulator between one AC power source and its load, or as VAR compensator as well as active power conditioner between phases of a multiphase AC option.

DC-AC inverter with overload driving capability

Abstract: A DC-AC inverter includes a bridge converter for converting an input DC into an output AC signal which uses field-effect transistors in the bridge circuit. The characteristics of the field-effect transistors enable the bridge converter to temporarily supply power in significant overload conditions. A DC-DC converter may also be included between the DC power source and the bridge converter to provide voltage boosting, when required. Field-effect transistors are also included in the DC-DC converter for power switching. The duration and amount of overload current output by the bridge converter is monitored and when an overcurrent condition beyond a predetermined amount or duration is detected, the bridge converter is disabled. The bridge converter is reenabled at a predetermined time thereafter. A plurality of field effect transistors may be connected in parallel at each location wherein a solid state power switching device is used in the inverter to thereby multiply the power handling capacity of the inverter as a whole.

Dual output DC-DC converter with independently controllable output voltages

Abstract: A single DC power switching converter feeds two DC load circuits from two transformer secondary windings. One winding is tightly coupled to the primary and its output voltage is controlled using pulse-width modulation. The other secondary winding is loosely coupled to the primary so that its leakage inductance resonates with a secondary capacitor such that its output is controlled by converter frequency adjustment. Thus, both output voltages are controlled using a single power switching stage.

Direct current power supply using current amplitude modulation

Abstract: A switched-mode power supply for producing a DC voltage output from a unidirectional-current or alternating-current input uses amplitude modulation of current through and inductor. Input terminals joined to the inductor receive the input. A switch in series connection with the inductor responds to a switching signal for controlling the inductor current. A capacitor and diode store energy received from the inductor. A computation circuit is joined to a switch control circuit for sensing the inductor current and producing a switching signal for opening the switch when the inductor current reaches a desired maximum. A reference voltage generator, which produces a signal indicative of the maximum inductor current, includes an adjustment circuit for modulating an error signal, derived from an integral of the difference between a desired output voltage and the actual output voltage, by the input voltage. Inductor current is thereby modulated in phase with input voltage. A quick response circuit is provided for controlling rapid fluctuations in the output voltage. An alternating current source is provided which includes a resonant oscillator for producing an alternating current having a substantially pure sine wave output. A thermally-activated safety switch is also provided for absorbing energy when high voltage surges appear on the input terminals of the power supply.

Study of a resonant converter using power transistors in a 25KW x-rays tube power supply

Abstract: This paper describes a converter whose purpose is to feed an χ-rays tube (25 KW, 140 KV) from the industrial main power supply (380 V, 50 Hz). The authors justify the structure of this generator that is constituted by an inverter using power transistors and a transformer-voltage multiplier set which are connected by a series resonant circuit. The control logic of the transistors gives them the dual properties of these of thyristors. An accurate analytical study of this system allows to predetermine the characteristics of this converter now in its industrialization phase.

Power converter apparatus and control method thereof

Abstract: A power converter apparatus has at least two converters CONV1 and CONV2. The DC side of each of the converters CONV1 and CONV2 is connected to a filtering capacitor Cd which serves as a DC power source for a load device LOAD. The AC side of the converter CONV1 is connected to the secondary winding of a first transformer TR1. The AC side of the converter CONV2 is connected to the secondary winding of a second transformer TR2. The primary winding of transformer TR1 is connected in series to the primary winding of transformer TR2. The series circuit of the primary windings of transformers TR1 and TR2 is coupled to an AC power supply SUP via a single AC reactor Ls. A control method of the invention is adapted to the power converter apparatus in which plural PWM converters are used. The phase of a modulating wave (carrier) of one PWM converter differs by a predetermined degree from that of another PWM converter.

A DC to 3-Phase Series-Resonant Converter with Low Harmonic Distortion

Abstract: A type of dc to 3-phase series-resonant converter (s.r.converter) or potentially submegawatt industrial applications is presented. The converter provides variable-frequency sine-wave currents, with low harmonic distortion at the output terminals, and with the frequency ranging from -200 through dc to +200 Hz. The converter can transfer power in both forward and reverse power-flow directions to almost any type of load circuit. The methods of control are formulated such that they can be implemented easily with high-speed logical circuits. Test results for a 1-kW demonstration converter are supplied.

Optimal Design Strategy of Switching Converters Employing Current in jected Control

Abstract: This paper analyzes a buck/boost regulator employing current-injected control (CIC). It reveals the complex interactions between the dc loop and the current-injected loop and underlines the fundamental principle that governs the loop gain determination. Three commonly used compensation techniques are compared. The integral and lead/lag compensation are shown to be most desirable for performance optimization and stability.

Charging control system in solar generating device

Abstract: PURPOSE: To obtain a charging control system high in working efficiency by removing a DC/DC converter when the ratio between the input voltage and the output voltage of the DC/DC converter is kept between the conversion efficiency of the DC/DC converter and the reciprocal of said conversion efficiency. CONSTITUTION: When an accumulator 3 has a level less than a full charge mode, the DC voltage generated by a solar battery 1 is raised or dropped via a DC/DC converter 5 after a switch 12 is closed. Then a charging current and a load current are supplied to the accumulator 3 and the load 4 respectively in response to the output voltage of the converter 5. While the rise and drop are nor required for the output voltage of the battery 1 by the function of the converter 5 when the ratio between the output voltage V 0 and the input voltage V i of the converter 5 is kept between the conversion efficiency FC of the converter 5 and its reciprocal 1/FC. Thus an input/output voltage comparison control circuit 9 opens the switch 12 and separates the converter 5 from the load 4. COPYRIGHT: (C)1987,JPO&Japio

The application of power MOSFETs at 10MHz

Abstract: The design and performance of a 10MHz dc/dc converter is discussed. The behavior of the power MOSFET at this frequency, and the integration of device parasitics into the circuit are described. The performance of a 50W converter is compared with the predictions of a detailed simulation. Losses are analysed and shown to be dominated by MOSFET switching.

Current-source power converting apparatus with self-extinction devices

Abstract: A current-source power converting apparatus having a three phase AC-DC converter composed of self-extinction devices for converting an AC power furnished from an three phase AC power source into a DC power and a DC-AC inverter connected with the AC-DC converter through a DC reactor for re-converting the DC power into a three phase AC power to supply the re-converted power for a load. When the failure of the AC power source is detect according to one embodiment, the AC power source is detached from the AC-DC converter and a battery is connected between arbitrary two phases at the input end of the AC-DC converter. After that, the DC power of the battery is supplied for the DC-AC inverter intermittently by switching the corresponding self-extinction devices of the AC-DC converter and controlled by varying the duty ratio of the switching operation.

Control circuit for power converter apparatus

Abstract: Disclosed is a control circuit for a power converter apparatus using self-extinction devices as switching devices, in which turn on and turn off operations of the self-extinction devices are controlled by gate pulses which have been subject to pulse width modulation with a pulse train having a pulse width which is sinusoidally varied, and, at the same time, the self-extinction devices in same phase are made conductive in a predetermined period corresponding to an output voltage reference value to make an output of the power converter apparatus be in a shorted state in the sense of DC current to thereby control the output of the power converter apparatus

Novel operation and control modes for series-resonant converters

Abstract: A series-resonant converter (SRC) able to generate an output voltage either lower or higher than the source voltage is described. Moreover, a novel control scheme is presented which renders two degrees of freedom for control and which guarantees symmetrical steady-state waveforms in all operation modes. Both the average resonant current as well as the peak voltage of the resonant capacitor can be controlled independently. Special attention is given to an operation mode which facilitates converter operation when the output voltages approximately equal the source voltage (q approx equal to 1). Test results are presented of both controller and converter.

Communication receiver system having a voltage converter with an operating frequency below the receiver IF

Abstract: A communication receiver system for receiving coded signals and of the type having at least one predetermined intermediate frequency (IF) signal comprising a decoder for detecting and decoding the received coded signals and a DC/DC voltage converter circuit, connected to the decoder, for generating a voltage greater than the supply voltage of the communication receiver system at a frequency below the frequency of the IF signal. The system further comprises a frequency trim circuit, connected to the voltage converter circuit, for controlling the operating frequency of the DC/DC voltage converter circuit whereby interference with the IF signal is prevented.

Switched power supply comprising a free-running flow converter and electrically separated control loop

Abstract: A switched power supply has a rectifier arrangement for generating a DC voltage from an input AC voltage. A converter arangement in the power supply has a switching transistor and a transformer. The converter arrangement is designed as a free-running flow converter, whereby the switching transistor is switched on in the current-free condition. A control stage with an electrically separated control loop is provided at the secondary side, whereby the control stage acquires the deviation of an output DC voltage from a prescribed value and sets the pulse duty factor for the switching transistor via the control loop.

Circuit arrangement for feeding the regulation and control device of a regulated direct voltage converter

Abstract: In a circuit arrangement for energizing the regulation and control device (RS) of a regulated direct voltage converter (GW), a charging capacitor which supplies the regulation and control device (RS) is charged during the starting stage by the input voltage (U1) of the direct voltage converter and during the operating condition by an auxiliary voltage (UH) at the secondary side of the converter (GW). The change-over takes place by means of a threshold value switch (S), which switches off a constant-current source (U1,IC) that can be switched on and off as soon as the voltage at the charging capacitor (C) exceeds by a given amount a reference voltage (Uref). The circuit arrangement exhibits particularly low losses during the operating condition of the direct voltage converter.

Current fed boost converter

Abstract: A power supply comprising a high impedance source and a regulator configured as a boost type converter is disclosed. The duty cycle of a shunt switch in the regulator is controlled so as to be increased or decreased in order to respectively decrease or increase the regulator output voltage.

Power converter control apparatus and power converter control method

Abstract: A power converter control apparatus includes an automatic power controller (APC) for controlling a rectifier (1A) and an automatic reactive power controller (AQC) for controlling an inverter (1B). The inverter (1B) is coupled via DC power transmission lines (3) to the rectifier (1A). An output (E44) from the automatic power controller (APC) is utilized to change a control angle (or margin angle) of the inverter (1B) if a DC current (ld) flowing through the DC power transmission lines (3) increases to exceed a rated current value of the apparatus, thereby allowing a stable power transmission.

High efficiency transformerless AC/DC converter

Abstract: An electronic power supply that converts alternating current to a regulated DC voltage with high efficiency is accomplished by a switch that connects the input AC power source directly to the DC output filter capacitor. This occurs when the input voltage equals the output voltage, and the output voltage is less than the set value. This power supply can be used with low impedance AC power sources capable of providing high surge currents such as commercial utility lines.

The double converter: A fully regulated two-output dc-to-dc converter

Abstract: A new type of two-output dc-to-dc converter is proposed. With this “double converter”, two completely regulated outputs can be obtained using only one switching element and very often without a transformer. The operating principle is based on the discontinuous-conduction mode operation of one output and the continuous-conduction mode operation of the other output. Both outputs are sensed and the duty-cycle of the switching element and the frequency are controlled. A prototype has been built and the results obtained are discussed.

Opto-electrical signal converter with stabilization

Abstract: The invention relates to an opto-electrical signal converter for linearly converting a signal consisting of an alternating current superimposed on a direct current into a signal consisting of an alternating voltage superimposed on a direct voltage. Such a converter comprises the combination of a light diode and a photosensitive element optically coupled therewith, which combination is designated as optocoupler. The invention has for its object to provide a converter having a good linear signal transmission, the value of the output signal of the converter being independent of the properties of the optocoupler used. For this purpose, the converter is provided with a transistor, of which a semiconductor junction connected to the base of the transistor is AC-connected parallel to the base-emitter junction of the transistor and is DC-connected in series with a stabilization circuit. As a result, a linear AC and DC transmission, respectively, is reached independently of ageing and of the temperature behaviour of the optocoupler used.

Two stage weighted capacitor digital to analog converter

Abstract: A weighted capacitor digital to analog converter is disclosed which requires two stages but only one conversion step. By the use of an applied reference voltage and two groups of capacitors, the outputs of each group being coupled to an amplifier and feedback capacitor circuit, various capacitors in these groups can be selectively switched from the reference voltage to ground potential in response to input binary digit signals thereby presenting a predetermined amount of voltage to the output amplifiers depending upon the number and particular combination of capacitors switched or non-switched to ground.

Monitoring switch mode converter performance utilizing duty cycle

Abstract: A method and circuitry are disclosed for monitoring the performance of a switching system such as a switch mode converter by monitoring the duty cycle of the system. With respect to a switch mode converter, its duty cycle is a parameter which determines whether or not the converter is in jeopardy of loosing its ability to regulate an output voltage. As long as the duty cycle of the converter is below a given threshold, which may approach 100 percent, the converter has the ability to continue regulating the output voltage. The method and circuitry disclosed herein monitor a signal of the converter having a duty cycle related to the duty cycle of the converter and provide a signal indicating when the duty cycle of the converter is equal to or greater than a predetermined threshold duty cycle.

Switch-mode power supply having a free-running forward converter

Abstract: A switch-mode power supply has a rectifier for producing a small d.c. voltage from an input a.c. voltage, and a converter which comprises a switching transistor and a transformer. The converter arrangement is a free-running conductive converter and the switching transistor is switched on in the currentless state.

Electrical short-cicruit monitoring arrangement for variable-speed, three-phase motors, including their feed lines

Abstract: An electrical short-circuit monitoring arrangement for a three-phase motor, including its supply lines, whose speed is controlled by a constant-current d.c.-link converter. The harmonic ripple voltage superimposed on the motor voltage generated as a consequence of the commutation by the constant-current d.c.-link converter at the output of the converter is determined, filtered, and supplied to a phase-monitoring unit, which when dropping below a selected amplitude variable of the harmonic voltage of at least one phase, triggers the switching module whose switching mechanism activates a disconnect switch to interrupt the motor circuit upon occurrence of a switchoff signal.

Apparatus for generating a multi-frequency signal

Abstract: An appartus for generating a multi-frequency signal includes a D/A converter, two converter circuits connected to the D/A converter for determining a respective connecting instant, two controlled waveform counters each being connected to a respective one of the converter circuits, a D/A cycle control connected to the converter circuits for monitoring the converter circuits, a sample-and-hold circuit having divider capacitors and being connected to the D/A converter, and holding capacitors connected to the sample-and-hold circuit.

Method of operating a copper converter

Abstract: An improved method of operating a converter for producing copper includes introducing at least a part of a flux and a cold charge in powdery form into a molten charge in the converter through at least one lance.