Showing papers on "Boost converter published in 1987"

Integrated uninterruptible power supply for personal computers

Abstract: A method and apparatus for providing uninterrupted DC and AC power for a desktop personal computer is described. The source of the uninterrrupted DC and AC power is derived from an integrated power supply that is sized to fit within the existing housings of most desktop personal computers as a plug-in replacement for existing power supplies. A high degree of efficiency is obtained using an integrated design with the main power conversion derived from a DC/DC dual primary resonant converter. The main primary of the resonant converter is driven from a high voltage DC bus which is supplied from AC mains when available. When the AC mains is unavailable, the second primary of the DC/DC dual primary resonant converter receives power from a low voltage battery source. Secondaries of the converter produce low voltage DC for driving the personal computer, high voltage DC for augmenting the high voltage DC bus, which in turn is used to drive a DC/AC inverter for supplying uninterrupted AC voltage for powering peripherals such as a monitor, printer, etc. A medium-voltage secondary is also sourced from the converter which drives a battery charger to recharge an internal battery pafck upon restoration of the AC mains.

Apparatus for controlling electric motor

Abstract: A control apparatus for controlling the main circuit for driving an AC electric motor consisting of a diode converter and a pulse width modulation (PWM) power converting device, in which it is arranged that the DC current as the output of the diode converter is detected by a current detector, the AC component of this DC current is filtered through a high-pass filter, and a pulse-width-modulation control is exercised by a control circuit in response to the output of the high-pass filter so that the DC current as the output of the diode converter may be smoothed out in the main circuit by the PWM power converting device. By such arrangement, this control apparatus of an electric motor is made smaller in size and simplified in structure and enabled to control the power factor of the power source of the diode converter to close to 1.0.

Development of a Unipolar Converter for Variable Reluctance Motor Drives

Abstract: A new converter concept for driving the switched reluctance motor has been developed. This converter has only one switching device per phase, uses a unipolar dc supply, returns all the trapped energy to the source, and does not require bifilar windings; it is called a C-dump converter because the trapped energy is dumped in a capacitor and then returned to the dc source. The topology for several different C-dump converters is presented. In addition, the design and experimental results for a C-dump converter using a chopper to recover the energy dumped on the capacitor are presented.

Inductor current control circuit

Abstract: A DC to DC power converter having reduced switching loss for operation at high frequencies. As disclosed, a buck, or forward, converter includes a first FET as the switching device in series with an inductor and a second FET as the flywheel device. At the common node to which the two FET's and the inductor are connected, there is sufficient capacitance that the FET's may be turned off without appreciable voltage change across the FET's. The value of the inductor is chosen, with respect to the input and output voltages and frequencies of operation involved, to insure that the inductor current polarity reverses each cycle, raising the node voltage to the level of the input voltage, substantially eliminating turn-on losses of the first FET. Control circuitry is provided for regulation of the power converter to control the peak-to-peak current in the inductor and to insure that at least a selected minimum value of the inductor current is present for each cycle of operation of the converter. An over-voltage protection circuit for the output of the converter is also provided.

Apparatus for converting DC to DC having non-feed back variable hysteretic current-mode control for maintaining approximately constant frequency

Abstract: An hysteretic current-mode controlled DC to DC converter has an input voltage, an output voltage and a control switch. The switch alternately coupled the input voltage into an energy storage inductor. It is controlled by an hysteretic conparater sensing the current of the inductor and having turn-on and turn-off limits. The limits are symmetrical about an average inductor current. The limits are adjusted by simple non-closed-loop methods to maintain an approximately constant frequency of oscillation. The average inductor current is controlled by an error amplifier to maintain a constant output voltage. The two controls are independent.

A new on-chip converter for submicrometer high-density DRAMs

Abstract: The converter described is a feedback-type voltage regulator which supplies a reduced voltage to an entire RAM circuit. A novel timing activation method was introduced to save power. The converter has been implemented on an experimental 4-Mb dynamic RAM. It was found that an even faster access time and higher reliability compared to a conventional design could be achieved by using an on-chip voltage converter and shorter channel transistors. This voltage converter is suitable for high-density, high-speed, and high-reliability DRAMs with submicrometer transistors.

Two-inductor boost and buck converters

Abstract: The derivation, analysis and design of a coupled inductor boost converter is presented. Aspects of the qualitative ac behavior of coupled inductor converters are discussed. Considerations for the design of the magnetics for such converters is addressed.

The Double Converter: A Fully Regulated Two-Output DC-DC Converter

Abstract: A new type of two-output dc-dc converter is proposed With this ``double converter'' two completely regulated outputs can be obtained using only one switching element and very often without an extra 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 switching frequency are controlled at the same time A prototype has been built, and the results obtained are discussed

Variable speed constant frequency power system with boost converter auxiliary output

Abstract: A DC link variable speed constant frequency power system is provided with a voltage boost circuit connected to receive voltage from a pair of DC link conductors and to supply voltage to an auxiliary supply bus. During normal system operation, the voltage boost circuit transfers the DC link voltage to the auxiliary supply bus. When a system fault occurs, such that the DC link voltage is reduced, the voltage boost circuit is activated to boost the reduced DC link voltage level and supply that boosted voltage level to the auxiliary supply bus.

Output hold-up circuit for a step-up voltage regulator

Abstract: An arrangement for enhancing the available energy storage capability of a hold-up energy storage element for use with the step-up or boost regulator stage of a power supply enables use of smaller hold-up storage elements, such as capacitors. The circuit stores energy at the boost regulator output and returns the energy either to the regulator input in the event of a transient line failure, or to the regulator output during a load transient. The invention provides improved transient fault tolerance by increasing the hold-up time of the storage element.

Frequency feedback on a current loop of a current-to-pressure converter

Abstract: A current-to-pressure (I/P) converter (20) provides an output pressure as a function of the magnitude of a variable input DC current. The I/P converter (20) includes a pressure sensor (64) which produces a feedback signal representative of the output pressure. Based upon the feedback signal and the magnitude of the input DC current, an electrical control signal is produced which controls a device (40) for varying the output pressure. The I/P converter (20) also includes a circuit (86) for generating a time-varying signal which is sent back over the current loop wires (28) through which the input DC current flows. The time-varying signal provides an indication of whether the I/P converter (20) is functioning properly. This permits diagnosis of possible causes of control system malfunctions without having to inspect the I/P converter (20) itself.

Integrated-magnetics power converter

Abstract: Novel switched mode boost-buck integrated magnetic power converters are disclosed featuring two winding bobbins, a new boost section with enhanced gain, means for operating the converter in a continuous mode of energy storage under minimum output loading conditions while providing adequate time for removing the magnetization energy of the transformer part of the integrated magnetics, and other new and different converter topologies.

Dc to dc converter current pump.

Abstract: A DC to DC power converter designated a synchronous current pump (13) and operated in the preferred mode in synchronization with a discharge circuit (11) and using a capacitor (28) as the energy storage element, and in the preferred embodiment has in series with said capacitor the battery supply (10), an inductor (30), a diode (27a), and the primary winding (31a) of a transformer (31); and across said storage capacitor is an energy transfer FET switch (33) which is used for discharging said capacitor and transferring its stored energy to an output load capacitor (4) connected through a diode (32) to the secondary winding of said transformer In operation, the current pump supplies power efficiently and smoothly to a load discharge capacitor in synchronization with operation of the discharge circuit

Phase controlled DC-AC converter with high frequency switching

Abstract: A novel type of the sinusoidal DC-AC converter is presented, where a pair of switches is placed in each side of the primary and the secondary of the isolation transformer. This converter is controlled by the phase difference between the two pairs of switches. As a result, the transformer is miniaturized by making the switching frequency high. This converter is especially suitable for small UPS systems.

DC-AC Series-Resonant Converter System with High Internal Frequency Generating Multiphase AC Waveforms for Multikilowatt Power Levels

Abstract: A new method of power pulse modulation with internal frequencies of tens of kHz which is also suitable for multikilowatt power levels is applied to a series-resonant converter system for generating synthesized multiphase bipolar waveforms with reversible power flow. The power circuitry of the converter is provided with one single high-frequency resonant link in the direct energy path. Natural current commutation of the thyristors is obtained by the use of a series-resonant circuit for power transfer and control. Consequently, switching losses can be reduced to a minimum without compromising the reliability of the solid-state components. The high pulse frequency allows the principle of modulation and demodulation for fast system response and output waveforms with reversible power flow with low distortion. Test results of a converter system generating three phases?sinusoidal waveforms independent of the load characteristics?demonstrate the significant aspects of this class of power conversion. The material presented indicates the possibilities for fast-acting polyphase dc-ac and ac-ac converter systems.

Design-oriented analysis of common switching DC to DC converters

Abstract: A general, computer-aided analysis of power electronic circuit dynamics is proposed. An automatic generation of dynamic models from a circuit specification is the starting point for a symbolic, automatable, exact, ‘top-down’ procedure, that contrasts with circuit-specific analyses. The algorithm is suitable for analysing any converter containing two reactive elements, covering the common switching power stages: buck, boost, buck-boost converters. The method is illustrated by application to the computation of the transient response of a boost converter; the computer results are compared with those obtained by applying the ‘state space averaging’ method and with laboratory results.

DC to DC converter

Abstract: A DC to DC converter of the switched capacitor kind is described in which controlled solid state switches are used to effect the switching and to limit the current passed to the capacitors in dependence upon that required to match a load.

Arc lamp power supply

Abstract: An improved high power (40,000 watt) high intensity arc discharge power supply which provides reliable, automatic ignition control and enables precise variation of lamp power in dual AC and DC modes of operation over an extended dynamic range from 400 watts to 40,000 watts. A capacitive boost circuit is provided to supply the high voltage necessary to ignite the lamp. Upon start-up, the voltage on a boost circuit capacitor is monitored by an ignition circuit which automatically enables the ignitor when the voltage is at the required level and switches the ignitor off when the lamp starts. After ignition the boost charging circuit is disabled and the power supply operates in a normal mode. The power supply operates on a three phase alternating voltage input through a three phase bridge, switches it through a drive transistor and then supplies it to an inductor. The signal is then supplied through an H-bridge commutator to the boost circuit, the ignitor and the arc lamp itself. The circuit operates under the control of an analog computer which determines the switching rate, monitors the voltage and current, provides power feedback and generally controls the power supply. A power command input signal determines the power level at which the arc lamp will operate. Below a certain lamp current level, an oscillator circuit controlling the commutator is disabled so the lamp will operate on DC power in a "simmer" or low temperature mode. The lamp is thus operated over a large dynamic range.

High efficiency battery adapter

Abstract: Extremely high efficiency is achieved in a DC to DC converter by using a relaxation oscillator in which two transistors alternately conduct current to the primary winding of a step-up transformer. The transistors are interconnected by a resistor and capacitor in series so that when the converter is lightly loaded, the saturable reactor in the circuit will be self-resonant, so as to draw only minimal power from the battery source. The converter also includes a battery charge level monitor circuit that prevents the DC to DC converter from oscillating and thus providing power unless the battery is above a minimum charge level when its voltage is applied to the converter. In a preferred embodiment, the converter provides an output of up to 100 watts.

Inductive power converter for use with variable input and output voltages

Abstract: A power converter for use in converting a variable DC input voltage into a variable DC output voltage is disclosed which uses control circuitry on both the input and the output to optimize converter performance. By charging the inductor up nearly to the saturation point, but completely avoiding saturation of the inductor, power capability at the input end is maximized. By discharging the inductor completely without either losing power capability by continuing to attempt to discharge the inductor after the charge is depleted or by failing to nearly discharge the inductor thereby presenting the possibility of saturation to the boosting of current through the inductor during the next charge cycle.

Start-up circuit for an integrated-magnetic power converter

Abstract: An innovative start-up circuit is disclosed which uses ordinary solid-state components and which may be used with a wide variety of switched mode boost-buck integrated magnetic power converters, including those having only two winding bobbins, a boost section with enhanced gain, and several new and different core arrangements. The start-up circuit comprises a winding which is transformer coupled to the drive transformer, a capacitor which is charged by the application of power to the input of the converter, switching means for switching current from the input of the converter to the drive transformer in response to the charging of the capacitor, and means for preventing the capacitor from operating the switching means after the converter is placed into operation.

Variable input voltage DC to DC converter with switching transistor drive current regulator

Abstract: The DC to DC converter includes a coupled inductor having a primary winding and a feedback winding. A drive current regulator circuit receives a variable input voltage from the feedback winding but transmits a constant base drive current to the base terminal of the converter switching transistor. The base drive regulator circuit thereby enables the DC to DC converter to operate at high levels of efficiency over wide ranges of DC input voltages such as twelve to forty-eight volts DC.

Strobe flash lamp power supply with afterglow prevention circuit

Abstract: A variable frequency DC to DC converter generates a pulsed, variable magnitude output voltage where the frequency of the pulsed output voltage varies with changes in the magnitude of the output voltage An energy storage capacitor is coupled between the converter coupled inductor and strobe flash lamp or other gaseous discharge tube and is periodically discharged through the flash lamp A variable impedance device in the form of a capacitor is coupled in series with the flow of current from the coupled inductor into the energy storage capacitor to provide a low impedance current flow path when energy is transferred from the coupled inductor into the capacitor and to provide a high impedance current flow path between the converter DC voltage input terminals and the energy storage capacitor when energy is transferred from the capacitor into the strobe flash lamp

A high frequency AC/DC converter with unity power factor and minimum harmonic distortion

Abstract: A new forced commutated ac/dc converter and control strategy is proposed that is able to draw nearly sinusoidal currents at unity power factor from three-phase power lines. The power factor is controlled by adjusting the relative position of the fundamental component of an optimized PWM type voltage with respect to the supply voltage. Current harmonic distortion is minimized by the use of optimized firing angles for the converter at a frequency where GTO's can be used. This feature makes this approach very attractive at power levels of 100 kW to 600 kW. An 8096 microcontroller is used to minimize the interface hardware requirements. This paper presents the theoretical analysis of the converter, the control strategy and experimental results for a low power prototype.

Electronic load for testing transformers

Abstract: An adjustable electronic load for testing current transformers and/or voltage transformers, the load having connected, between its input current terminals, a series connection including the input of a current-to-voltage converter and the output of a controlled generator, and having connected, between its input voltage terminals, the input of a voltage-to-voltage converter. The outputs of the current-to-voltage converter and the voltage-to-voltage converter are each connected via an impedance to a control input of the controlled generator. The voltage-to-voltage converter and the current-to-voltage converter each comprise at least one amplifier with adjustable amplification. The amplifications of the two adjustable amplifiers are adjustable jointly in opposite directions. In the case of a load for testing a current transformer, with the rated secondary power of the current transformer being predetermined, the amplification of the current-to-voltage converter is reduced or increased and the amplification of the voltage-to-voltage converter is increased or reduced respectively, so as to increase or reduce the rated secondary current, respectively. In the case of a load for testing a voltage transformer, with the rated secondary power of the voltage transformer being predetermined, the amplification of the voltage-to-voltage converter is reduced or increased and the amplification of the current-to-voltage converter is increased or reduced respectively, so as to increase or reduce the rated secondary voltage, respectively.

Automatic offset compensating bipolar A/D converter circuit

Abstract: An automatic offset compensating bipolar A/D converter circuit includes an A/D converter and a feedback circuit, which automatically compensates offset error between a specific level of input having analog voltage and a specific output code of output digital value corresponding to that input analog voltage. The A/D converter can convert the input analog voltage, which includes residual noises more than 1 LSB, into an output digital value. The feedback circuit can add a compensation voltage to the input analog voltage so as to equalize the posibilities of occurrence of codes which are more than and less than a specific output code of an output digital value to each other in accordance with an output digital value.

DC to DC converter with overvoltage protection circuit

Abstract: An overvoltage protection circuit limits the output voltage of a DC to DC converter to a maximum desired output voltage. An output voltage sensing circuit includes a semiconductor device such as a sidac having a normal resistive region of operation as well as a negative resistance region of operation which begins at a breakover voltage and extends into a foldback region. One terminal of the sidac is coupled to sense the converter output voltage while the second terminal opposite end of the sidac is coupled to a biasing device in the form of a resistor which generates an overvoltage signal when the sidac conducts current. The overvoltage signal from the biasing resistor is coupled to a converter switching transistor disabling circuit which reduces the converter output voltage to a level below the maximum desired output voltage in response to the overvoltage signal.

DC power transmission system

Abstract: In a DC power transmission system wherein two AC systems are interconnected by a first converter, a DC transmission line and a second converter to transmit power from one of the AC systems to the other of the AC systems via the DC transmission line, the DC power transmission system is provided wherein at least one of said first and second converters operating as an inverter is a current type self-commutated converter capable of being pulse-width controlled, the reactive power of the current type self-commutated converter is regulated by controlling a phase difference angle between its AC voltage and current, the DC voltage is regulated by pulse-width controlling the current type self commutated converter, and the DC current is regulated by the converter operating as a rectifier.

Static converter comprising a protective filter against high-frequency disturbances

Abstract: The protective filter comprises an internal reference plane, electrically insulated from the converter housing and acting as ground plane for the internal elements of the static converter, and filtering capacitors respectively connecting the internal reference plane to the input and output cables of the converter.