Showing papers on "Boost converter published in 1982"

A Regulated DC-DC Voltage Source Converter Using a High Frequency Link

Abstract: Power converters which employ a high frequency (HF) link possess several attractive features such as reduced size of reactive components, fast response, and ease of commutation. Either series or parallel connection of the load to the link capacitor can be employed by such converters. Converters that have a series link capacitor-load configuration are seen by the load as a current source. A dc-dc converter which uses a parallel link capacitor-load configuration is investigated. The output dc voltage is regulated by varying the link frequency. Such a converter behaves as a voltage source and is suitable for voltage source inverter applications. The converter is analyzed. Based on the analysis, a design procedure is given. A control scheme is outlined. Results from a prototype converter are presented.

Electronic welding apparatus

Abstract: An electric welding apparatus which, for controlling at least one welding parameter, such as welding voltage or welding current, comprises a switching mode power supply (SMPS) as control element, the switching mode power supply preferably being regulated on the primary. The actual values of voltage and current are taken from the output of the switching mode power supply and fed to an analog control circuit. The set values of voltage and current are fed to a microprocessor via an entry keyboard, and in the microprocessor they are stored in a memory and passed on in analogous form to the analog control circuit which carries out a comparison of set value and actual value and, in dependence thereon, produces an error signal that is fed to a pulse width modulator of the switching mode power supply. The pulse width modulator is connected to the driver stages of the switching stages of the switching mode power supply, which switching stages are designed as boost regulator of buck regulator, and thus a pulse width modulation of the current pulses of the switching stages is effected in dependence on the difference between actual and nominal value. The converter section of the switching mode power supply preferably is designed as a modified single-ended buck regulator or as a push-pull full bridge, wherein it is operated at a fixed clock frequency of about 25 kHz. The secondary coil of the transformer of the switching mode power supply being either direct in connection with the output connection terminals of the switching mode power supply, or a secondary rectifier is connected between the secondary coil and the output connection terminals, whereby the secondary rectifier can be bridged by switch means.

High frequency DC-to-DC converter

Abstract: A power conversion circuit is operated at high frequency in the radio frequency spectrum to utilize adjunct reactive impedances of the active semiconductor devices as part of an impedance transformation circuit. Power is transferred through the converter at substantially a single frequency. Energy storage of the adjunct reactances is positively utilized to limit power dissipation within the converter.

Control apparatus for D.C. power transmission system

Abstract: This invention relates to an apparatus for controlling a D.C. power transmission system having a line-commutated converter which is connected between a first A.C. system and D.C. power transmission lines and which performs power conversion between A.C. power and D.C. power, and a forced-commutated converter which is connected between the D.C. power transmission lines and having a second A.C. system and which performs power conversion between A.C. power and D.C. power. In order to control transmission power in the two-terminal D.C. power transmission system wherein the two A.C. systems are associated by direct current, a control apparatus for a D.C. power transmission system according to this invention includes a voltage detector which detects a D.C. voltage of the D.C. power transmission lines, a first control circuit for comparing the output of the voltage detector with a voltage reference signal and for controlling ignition of the self-excited converter in accordance with the comparison, a detector which detects a current which is proportional to the conversion power of the line-commutated converter, and a second control circuit for comparing the output of the current detector with a power reference signal and for controlling ignition of the line-commutated converter in accordance with the comparison.

Supply for providing uninterruptible d-c power to a load

Abstract: A system for supplying uninterruptible d-c power to a load. When the system operates in its normal mode, d-c load power is provided by the combination of a rectifier and a power switch. The d-c output of the rectifier may be used by a d-c to d-c down converter to recharge and maintain a battery if a separately powered source is not available for that purpose. A d-c to d-c up converter provides a relatively high amplitude d-c voltage from the battery voltage. The amplitude of this voltage is lower than the amplitude of the d-c output of the rectifier in the normal mode. When the amplitude of the rectifier output falls below the d-c to d-c up converter output voltage, the system changes to its failure mode and the battery provides d-c power to the load. The operation of the down converter if it is included in the system is inhibited.

Cascade-comparator A/D converter

Abstract: In an A/D converter in which a first comparator A/D converter for providing the most significant bits of a digital output and a second comparator A/D converter for providing the least significant bits of the digital output are cascaded, a switching circuit is provided between the first A/D converter and the second AID converter This switching circuit is responsive to the comparison between an analog input voltage and first comparison reference voltages in the first AID converter to apply two adjacent first reference voltages between which the analog input voltages lies to both ends of a voltage dividing circuit network of the second A/D converter to thereby provide second comparison reference voltages In the second A/D converter, the second comparison reference voltages are compared with the analog input voltage by comparators, to provide the least significant bits of a digital output

Resonant current-driven power source

Abstract: A resonant current-driven power source is disclosed. Preferably, the power source is a DC to DC converter regulator including an inductor and capacitor electrically coupled to one another and an input inverter which converts an input DC voltage into an AC voltage having substantially no DC component and applies the AC voltage across the inductor and capacitor in a manner which causes the inductor and capacitor to resonate with one another whereby an AC voltage appears across the capacitor. An output circuit converts the AC voltage appearing across the capacitor into a DC output voltage. A control circuit is provided for controlling the operation of the inverter circuit in a manner which controls the magnitude of the output voltage.

Ripple determination for switch-mode DC/DC converters

Abstract: The state-space average model of a DC/DC convertor is used directly to obtain expressions for the ripple in any state or output of the model. This is used to rederive the current-ripple trade-off conditions in the Cuk convertor in a more straightforward fashion. In addition, it is shown that the buck convertor with input filter inductor and storage inductor coupling, and boost convertor with output filter inductor and storage inductor coupling, have similar ripple behaviour to the Cuk convertor at one port when the other port ripple is zero. For the case of equal input and output current ripples, the coupled inductor boost and buck are shown to be superior to the Cuk convertor.

Converter control apparatus for parallel connected multi-terminal direct current system

Abstract: Two rectifiers and two inverters are operated under the state under which they are connected in parallel by common transmission lines. These rectifiers and inverters are controlled an independent control apparatus respectively which can selectively apply either the constant current control or the constant voltage control. The control apparatus of each converter has bestowed thereon the reference value of a current to flow through the particular converter and the reference value of a terminal voltage of the particular converter. A signal for lowering the current reference value is added to the control apparatus of one or all of the converters which are to be operated as the inverters. On the other hand, a signal for essentially rendering the terminal voltage of the converter smaller than the voltage reference value is added to the control apparatus of the converter which is to be operated as the converter for determining the voltage of a direct current system.

Microprocessor supervised analog-to-digital converter

Abstract: An analog-to-digital converter which is supervised by a microprocessor and includes means for digitally compensating for initial gain and offset errors and gain and offset drift errors due to temperature variations. An analog input voltage is applied to a first analog-to-digital converter, the output of which is both stored in the microprocessor and applied to a linear digital-to-analog converter. The output of the linear converter is summed with the original analog input voltage and the difference applied to the conversion apparatus as an unknown input signal. This process is continued to achieve a desired resolution. The output of a differential temperature sensor is similarly processed to determine the proper amount of compensation for gain and offset drift. The microprocessor provides both control and computation capabilities.

Improvements in or relating to d.c. converters

Abstract: A d.c. converter which produces a d.c. output voltage from a lower d.c. input voltage is arranged so as to minimise the ripple voltage present on the output and the ripple current which is present at the input. Instead of using a single switch to chop the input voltage in the conventional manner, two serially connected switches are used with one switch being 180° out of phase with the other. A capacitor is connected across each switch and because of the 180° phase shift, the two voltages across each capacitor do not add arithmetically. By correctly choosing the output voltage in relation to the input voltage, the ripple values can be reduced to negligible levels without the need to increase the value of the associated reactive components. A converter circuit which is capable of handling power flowing in either direction is described.

Fluorescent lamp safety lighting

Abstract: 1. Fluorescent-lamp-type safety light, in which the fluorescent lamp, in normal operation, can be operated via a bridge rectifier (6) which is followed by a supporting capacitor (8) and a DC/AC converter (9) from an alternating-voltage supply system (L', N) and, in emergency operation, can be operated via a DC/AC converter (9) from a battery (3) and the battery can be charged by means of a charging device (1) from the alternating voltage supply system (L, N), characterised by the following features : - the alternating-voltage side of the bridge rectifier (6) is connected via a filter (7) to the alternating-voltage supply system (L', N), - the direct-voltage side of the bridge rectifier (6) is connected to the supporting capacitor (8), to the input of the DC/AC converter (9) and, via a blocking diode (5), to the output of a direct-current converter (4), - the input of the direct-current converter (4) is connected to the battery (3).

High voltage converter

Abstract: A high voltage converter converts an incoming high frequency pulse voltage to a direct voltage at a level which can be varied by varying the pulse width. The converter contains a transformer (T) with its primary side (p) connected to a pulse source (U) and to a controllable switch (K). The secondary side of the transformer is divided into two sections (s 1 , s 2 ). One section (s 1 ) is connected to a rectifier in the form of a conventional voltage doubler circuit (D1, D2, Cd1, Cd2) with capacitors in parallel with the secondary winding sections (s 1 , s 2 ). The other section (s 2 ) is connected to a rectifier bridge (D3-D6) and a smoothing filer (L f , C f ). The converter output is the doubler circuit output in series with the smoothing filter output.

Evaluation and implementation of the optimum magnetics design of the cuk converter in comparison to the conventional buck-boost converter

Abstract: Magnetic components such as inductors and transformers constitute one of the major ingredients of a switching power processing system. This paper presents a detailed comparison and implementation of the magnetic component designs of two functionally similar switching power converters, i.e. the conventional Buck-Boost converter and the new topology Cuk converter, both of which are capable of either stepping up or stepping down the input voltage. A cost effective, computer-aided design approach using the nonlinear programming (NLP) technique is employed to design the magnetic components of these two converters such that the total weight of each converter is minimized respectively.

A four-quadrant current regulated converter with a high-frequency link

Abstract: A novel and highly versatile four-quadrant static converter is discussed. A resonant high frequency link is employed which provides an extremely fast response to external commands and a wide frequency range of converter operations. This converter is therefore very suitable for four-quadrant DC chopper and constant or variable frequency inverter applications.

Characteristics of a New Series Resonant Converter

Abstract: This paper describes a new series resonant converter for a 150-volt dc power supply system. This converter has been studied in order to overcome the disadvantage of conventional series resonant converters which must widely vary the conversion frequency to keep the output voltage constant, thus causing audible noise under light-load conditions. A series resonsnt circuit is added parallel to the output circuit of the conventional converter. By utilizing the impedance characteristics of the additional circuit, the output voltage can be regulated with less conversion frequency variation than in conventional circuits. From experimental results, the conversion frequency variation necessary to keep the output voltage constant in a 0-to-100 ampere output current range was found to be only about 30% of that of conventional circuits. The conversion efficiency of this converter is about 85% at 100 ampere output current.

Electronic flash device

Abstract: In the disclosed device, a DC-DC converter boosts the output of a battery to charge a capacitor that stores electrical energy to be converted into light energy and turns on a neon tube when the capacitor voltage reaches a first predetermined value. A control arrangement disables the converter in response to the neon tube turning on the re-enables the converter when the capacitor charge drops to the first predetermined level after the neon tube turns on.

A controllable power source

Abstract: A controllable power source is suitable for driving one or more electric motors from a low voltage battery. A converter steps up the d.c. voltage to a higher level at which the motors are designed to operate and a power regulator placed between the converter and each motor regulates the power which is drawn at the higher voltage by the motors. A current limit is imposed on the converter which is significantly less than the maximum current handling capabilities of the motors, so that when a motor attempts to draw an excessive current the output voltage of the converter drops accordingly. This enables the overall power handling capability of the converter to be minimize, while still allowing a motor to draw maximum current or maximum voltage, but not both simultaneously.

Controlling method for induction motor

Abstract: PURPOSE: To enable slip frequency to be controlled to always come to a proper value even if a primary resistance is fluctuated, by taking a signal in relation to a secondary resistance fluctuation of a motor from a voltage fluctuation quantity, and by controlling converter output frequency according to said signal CONSTITUTION: The output of current detectors 3U∼3W is fed to a coordinate converter 5 via a three-phase/two-phase converter 4 The outputs of the coordinate converter 5 and current regulators 15, 16 is fed to an arithmetic circuit 18 Output voltage fluctuation component due to the change of a secondary resistance of a motor 2 from the arithmetic unit 18 is applied to an adder 23, and the frequency of the motor 2 from an adder 26 is sent to a coordinate reference generator 13 and a voltage command arithmetic circuit 14 From the voltage command arithmetic circuit 14, the voltage component command of a revolving-field coordinate system is applied to adders 21, 22 and the output is sent to a coordinate converter 17 By the voltage command of a stator coordinate system from the coordinate converter 17, via a PWM controlling circuit 19, a power converter 1 is controlled COPYRIGHT: (C)1989,JPO&Japio

An improved switching converter model

Abstract: The nonlinear modeling and analysis of dc-dc converters in the continuous mode and discontinuous mode was done by averaging and discrete sampling techniques A model was developed by combining these two techniques This model, the discrete average model, accurately predicts the envelope of the output voltage and is easy to implement in circuit and state variable forms The proposed model is shown to be dependent on the type of duty cycle control The proper selection of the power stage model, between average and discrete average, is largely a function of the error processor in the feedback loop The accuracy of the measurement data taken by a conventional technique is affected by the conditions at which the data is collected

Subscriber line circuit comprising a controllable DC/DC converter as a battery feed circuit

Abstract: A subscriber line circuit comprises a controllable DC to DC converter (41) for producing a converter output signal which becomes a loop signal comprising a DC signal and/or a communication signal of a communication frequency band. First and second voltage signals are dependent (51, 69) on the current and the voltage of the loop signal, respectively. One of the voltage signals is amplified (71) with different transfer functions at DC and in the communication frequency band. The converter is controlled (85-86) by an error between a first sum (81) of the amplified signal and the other voltage signal and a second sum (82) of a reference voltage (E O ) and a signal supplied from an output (27) of an exchange. A subtractor (92) supplies a difference between the exchange output signal and the second voltage signal to an input (25) of the exchange. Preferably, terminals (16, 17) for connection to a subscriber substation are isolated at DC from terminals (18, 19) for connection to the exchange input and output.

Current sense circuit for a bubble memory voltage booster

Abstract: In a voltage boost circuit for use in conjunction with a bubble memory operational driver, an output transistor is alternately turned on and off. When turned on, current flows through an inductor. When turned off, a high voltage is built up across the inductor which causes charge to be transferred to and stored in a capacitor. When the output transistor is turned on so as to permit current to flow through the inductor, a ΔV BE /R current representative of the current flowing through the output transistor is compared with a ΔV BE /R reference current. When the first current reaches and exceeds the reference current, the output transistor is turned off.

Charging system for power storage battery of carriage truck

Abstract: PURPOSE:To effectively charge a storage battery by using a converter for supplying a DC load power source also as a DC converter for charging the battery, and controlling the converted voltage in response to the battery charging current and the load current. CONSTITUTION:The output voltage of a storage battery 6 is supplied to a drive motor 4 through a chopper controller 5 in a non-trolley zone. The voltage converted to DC from 3-phase AC collected through a current collector 1 from a 3-phase trolley from an AC/DC converter 2 is supplied to the controller 5 and the battery 6 in a trolley zone. At this time a gate control circuit 3 controls so that the sum of the load current and the battery charging current does not exceed the prescribed value, and controls the DC output voltage of the converter 2 so that the battery charging current becomes a set value.

Variable electronic impedance circuit

Abstract: A variable electronic impedance circuit contains a voltage-current converter having an input terminal which is supplied with an input signal voltage, and a variable-gain current amplifier having an input terminal which is supplied with an output current of the voltage-current converter. The output signal current of the amplifier is fed back to the input terminal of the voltage-current converter. In order to prevent undesirable oscillation immediately after the closure of a power supply switch, the variable electronic impedance circuit includes a control circuit which substantially inhibits the operation of the voltage-current converter for a predetermined time after the closure of the power supply switch.

Control circuit for a dc-ac converter

Abstract: For a d.c.-a.c. converter a control circuit is proposed which improves the efficiency of the converter and enables it to operate at a higherfrequency using the same semiconductor switches. For this purpose the residual voltage across the currently conductive switch (9, 10) is compared with a reference voltage (23) via an analog OR-gate (26) and the control signal for the conductive switch is controlled in such a way that the residual voltage is set to a desired value (19, 20, 21, 11, 13, 14). The converter with the control circuit is extremely suitable for use as a high-efficiency power-supply for fluorescent lamps and occupies the smallest possible volume.

The stability of DC/DC converters in current programmed mode

Abstract: Recent work on current programmed DC/DC converters has indicated.that these systems are unstable for duty cycles greater than 0–5 and this is independent of the precise configuration (boost, buck or buck-boost.) used in the converter. The purpose of this note is to show that the above result is incorrect ; the- boost and bunk-boost are always stable and the buck is stable for all duty cycles less than an amount determined by tin; circuit parameters and the switching frequency. In addition explicit expressions are obtained for the small-signal linearized model describing a converter in current programmed mode and an alternative method for stabilizing the buck converter is proposed.

The Design and Control of DC/DC Converters

Abstract: In this paper the design of fourth order (2 inductor/2 capacitor) pulse width modulated DC/DC converters with mutual coupling between the inductors is considered. Expressions relating the input and disturbances to the output voltage are obtained for the family of fourth order converters i.e. the buck with input filter, the boost with output filter and the buck/boost or Cuk. From these expressions, the effect of the various converter parameters on the open loop poles and zeros are investigated. A design procedure is described which aims at component selection based on both static power considerations and dynamic control criteria. This basically involves selecting inductances to satisfy current ripple requirements and capacitances to position the open loop poles and zeros favourably so that good transient response and disturbance rejection can be obtained with a simple 3 -term controller. As an illustration, a closed loop buck/boost (Cuk) converter is designed.

Overcurrent protecting circuit for dc/dc converter

Abstract: PURPOSE:To effectively operate a DC/DC converter even when a load is abruptly shortcircuited by protecting the primary or secondary coil current of a main transformer by utilizing the average value and the maximum value of the DC current corresponding to the primary or secondary coil current. CONSTITUTION:The input current of a DC/DC converter 1 is removed, a pulse width control circuit 2 is operated by the average current corresponding to the input current, thereby protecting the converter 1. The voltage corresponding to the maximum value of the input current of the converter is produced form a resistor RV2, and the difference between the voltage and the reference voltage E2 is obtained by a comparator 4. When the voltage corresponding to the maximum value of the input current of the converter 1 is larger than the reference voltage E2, a stop signal is immediately fed to a half-cycle stop circuit 5, and the vibration is stopped only during the half period.