Showing papers on "Buck–boost converter published in 1983"

An AC-to-DC Converter with High Quality Input Waveforms

Abstract: An ac-to-dc converter which draws sinusoidal and inphase current waveforms from the ac power source is described. Harmonic and power factor measurements obtained from a field- effect transistor (FET) converter operating at 45 kHz for a single- phase and a three-phase connection are presented. A stability analysis and design methodology are given.

Modulated power supply for an electrostatic precipitator

Abstract: In an electrostatic precipitator system powered by a primary power source, the power supply has a converter and a high voltage device. The converter can be coupled to the primary power source for producing a converter voltage with a different frequency content. The high voltage device is driven by the converter, producing from its converted voltage a high voltage. This high voltage is influenced by the different frequency content, having at least one frequency component at a predetermined low frequency which is sized to promote efficient precipitation.

Reactive-power compensation

Abstract: For reactive-power compensation in hydroelectric generators (1), a loss reduction is achieved by connecting a fixed compensation circuit (6) to the secondary side of a mains transformer (5, 5'), which is connected via a converter (4, 7) to the generator (1) and is switchable in steps on the converter side, and the converter is adjustable over a wide voltage range.

Start-up transient control for a DC-to-DC converter powered by a current-limited source

Abstract: The start-up trajectory of the operating point of a DC-to-DC converter normally includes a high current locus which must be traversed to reach the steady-state operating point. In the case of a converter powered by a current-limited source, such as a power supply system where one converter powers a plurality of subsequent converters, the subsequent converters may be unable to turn on due to inadequate current drive. By using a control circuit adapted to control the start-up trajectory of a DC-to-DC converter as a continuous function of the input voltage applied to it by the current-limited source, the start-up characteristics are constrained to be compatible to both source and load permitting the converter to proceed to its steady-state operating point.

High linearity digital to analog converter

Abstract: A digital-to-analog converter having high linearity about zero utilizes a magnitude/sign input code and comprises in combination a single unipolar digital-to-analog converter, a broad bandwidth, offset compensated amplifier and a circuit which multiplies the output of this amplifier by +1 or -1 depending on the sign code.

A water-level sensor using a capacitance to frequency converter

Abstract: A capacitive water-level sensor using PTFE-insulated wire and a capacitance to frequency converter is described. Construction is simple, yet overall linearity is 0.1%. Temperature drift of the sensor is -0.05%K-1 and that of the converter is <0.01%K-1. Long-term stability of the sensor appears excellent. The converter draws only 150 mu A from a 5 V supply and is insensitive to supply voltage variations.

Power supply unit for electronic flash

Abstract: A power supply unit for electronic flash includes a converter drive circuit which is activated when a main switch is turned on or in response to the completion of a shutter operation or the completion of a film winding operation, thereby driving a converter for oscillation. The converter charges a main discharge capacitor to a given voltage, and when the given voltage is reached, the converter drive circuit is deactivated, thereby automatically ceasing the oscillation of the converter.

Buck-boost converter with dual-mode control for battery charging

Abstract: A voltage controlled flyback converter used as a battery charging circuit avoids the power dissipation of the more conventional series-type regulator-type charging circuits but cannot be readily utilized because of the high gain in the feedback loop due to the battery voltage, which causes instabilities therein when it is operated in a continuous current mode. These instabilities are avoided in a flyback converter used for battery charging by using current control techniques to control current on the primary side of the converter during high-rate battery charging. During low-rate charging, normal voltage feedback from an output current sensing resistor is used as long as the converter operates in a discontinuous mode.

An 8b 50ns monolithic A/D converter with internal S/H

Abstract: An A/D converter, using a non-clocked successive approximation approach with an internal sample and hold amplifier, achieving an 8b conversion in 50ns, will be reported. Die size is 108×159mils and power dissipation is 300mW.

Floating battery feed circuit

Abstract: A floating battery feed circuit (10) comprising a switching-mode, flyback power converter (200) wherein a capacitor (C3) connected to a converter transformer winding (201) develops a relatively low voltage used to energize the converter control circuitry (100). The converter control circuitry prevents the operation of the battery feed circuit unless the voltage developed by the capacitor is above a predetermined magnitude. The power converter advantageously operates in only a constant-power mode regardless of loop impedance.

Flyback DC/DC converter with low ripple in the output capacitor

Abstract: A flyback type DC/DC converter includes an input filter with input capacitor (C₁), an inductance (L) in series with a power transistor (T) and an output filter with an output capa­ citor (C₂). The input capacitor (C₁) is connected in series with the output capacitor (C₂) and to the input terminals of the converter to compensate the ripple current in the output capacitor (C₂).

Electrical power source for resistance welding apparatus

Abstract: An electrical energy source with a static inverter and a welding transformer (12) for a resistance welding machine comprises a first static frequency converter (10) made up of semiconductor elements, the alternating output voltage of which has a frequency and pulse shape which differ from the frequency and pulse shape of the supply voltage fed to the inverter. In this connection, the pulse shape, the amplitude, and the pulse to space ratio are to be variable within wide limits. This is attained by at least one second frequency converter (11) connected in parallel to the first frequency converter (10), wherein the alternating output voltage of the second frequency converter (11) is adapted to be added in phase synchronism to the alternating output voltage of the first frequency converter (10) in the primary circuit of the welding transformer (12).

D.C. voltage converter including a pulse width controlled semiconductor switch

Abstract: A d.c. voltage converter having alternating energy intake and energy discharge phases. The converter includes a power transformer having a core and at least primary, secondary and tertiary windings associated with the core. A primary circuit including a pulse width controlled semiconductor switch connected in series with the primary winding conducts an energy intake current during the energy intake phase of the converter. A secondary circuit including a smoothing capacitor and at least one rectifier element connecting the smoothing capacitor to the secondary winding conducts an energy discharge current during the energy discharge phase on the converter. Circuit means are provided for connecting the tertiary winding to the smoothing capacitor so that, following the energy discharge phase of the converter, excess energy of the smoothing capacitor in the form of an energy feedback current is fed back into the core until the start of the next energy intake phase of the converter.

DC Static switch with phase commutation

Abstract: An apparatus for the interruption of DC transmission lines without substantial arcing utilizing in combination a DC circuit breaker, a DC-to-AC current converter, converter control and an AC power sink. Upon command from the converter control, DC current is converted to AC current in the current converter and is then magnetically coupled via a transformer into the AC power sink; thus, drawing power out of the DC transmission line and reducing the DC current toward a zero value at which point the DC breaker can be opened without substantial arcing. Various single and multi-phase converter circuits utilizing thyristors are employed. A bypass switch in parallel with the converter can be provided to pass the DC current around the converter during normal operation of the DC transmission line to minimize electrical losses. Alternatively in multi-phase converters, normal DC current can be multiplexed among the phases of the current converter in order to distribute the heating caused by the conduction of DC current therethrough. Interruption of DC transmission lines having bidirectional DC current flow is accomplished with alternate embodiments of the invention including current converters in a back-to-back parallel arrangement, or a current converter full wave bridge rectifier combination or a current converter connected to the DC transmission line via polarity reversing switches.

Converter control apparatus and method

Abstract: The input terminals of a PWM converter are connected to the a-c power supply via a reactor. A capacitor C as well as a load 11 are connected to the d-c output terminals of the PWM converter. An apparent phase of the power supply voltage E is shifted depending upon the difference between a d-c voltage detected across both terminals of the capacitor and a set voltage, and a control signal for the PWM converter is prepared, with the shifted voltage as a reference. When the detected voltage is greater than the set voltage, the PWM converter is so controlled as to be operated with a lagging power factor, and the a-c voltage at the input terminals of the PWM converter becomes smaller than the power supply voltage. Accordingly, the d-c voltage can be maintained at a value smaller than the set voltage.

Static phase converter

Abstract: Single-speed, three-phase motors and two-speed, three-phase motors are started and run by a static phase converter which comprises a timing circuit, adjustable for a starting interval, and a switching device which configures a plurality of capacitors, with respect to motor windings, so that a starting capacitance and a running capacitance are connected during a starting mode for a high-torque condition, and, thereafter, the run capacitance is connected for running the motor.

An improved push-pull voltage fed converter using a tapped output-filter inductor

Abstract: A new concept of using a tapped output-filter inductor and an auxiliary commutating diode to reduce the liklihood of transformer core saturation in a push-pull, voltage-fed converter is presented. The linearized circuit model and transfer functions are derived with a hybrid approach using both state-space and circuit averaging. Operation of the new converter—including parasitic effects—is discussed, and a design equation for inductor tap ratio is established. It is predicted and experimentally confirmed that the new converter has more symmetrical transformer core operation, and the potential exists for lower transistor turnon current and reduced transistor voltage stress. These benefits reduce switching loss and enhance transistor reliability.

Static semi-conductor electrical energy converter apparatus

Abstract: A static energy converter apparatus, having at least one converter Γ conforming to that described in U.S. Pat. No. 4,330,819, includes a supplementary output stage 21 adapted to produce an alternating current that changes direction upon each commutation of the controlled blocking static interrupters of the converter Γ. Stage 21 is such that the direction of the alternating current corresponds to the direction of circulation of current in the collector-emitter of each interrupter at the instant of commutation.

Characteristics of superconducting magnetic energy storage (SMES) energized by a high-voltage SCR converter

Abstract: A small-scale Superconducting Magnetic Energy Storage(SMES) unit was constructed using small magnets and a high-voltage converter, and the characteristics of this unit were examined. The high output voltage of the converter makes it possible for even a small magnet to charge and discharge large power. Moreover, converter control provides adequate protection during quenching. AC and DC filters can be eliminated from the converter system, and ripple voltage does not harm the superconducting magnet. These features demonstrated the potential of an SMES unit as a power system stabilizer and a peak load power supply.

Effect of the Selection of Input Voltage and Maximum Operating Flux Density of Different Core Material on the Optimum Design of Switching Power Converter

Abstract: The effects of using different input voltage and different core material of different saturation flux density on the switching power converter weight minimization are presented. The design- oriented sensitivity analysis by perturbing the operating point, for example, the input voltage and the maximum flux density, reveals valuable design insights into the switching power converter global design optimization. A cost-effective computer-aided nonlinear programming (NLP) design technique is utilized for the minimum weight design. The new topology Cuk switching converter is taken as a demonstration example. Detailed loss and weight breakdowns as a function of the input voltage and the operating flux density are calculated for the optimum operation. Significant differences of the overall power converter performances are observed by using different input voltages and saturation flux densities.

Single-ended DC converter

Abstract: The invention relates to a single-ended DC converter using the forward converter principle and having a current transformer and a flyback converter inductor, whose primary windings are connected in series. The transformation ratios of the current transformer and the flyback converter inductor are selected to be of equal magnitude. The rectifier elements on the secondary side are connected to the secondary windings of the current transformer and of the flyback converter inductor, and to one another, in such a manner that a continuous load current flows.

Pulse pneumatic pressure converter

Abstract: PURPOSE: To obtain a pulse pneumatic pressure converter storing an output pneumatic pressure even at power failure with high service life by using a piezoelectric flapper for a pneumatic-electric transducer, dividing a power supply into two systems and backing up only the circuit relating to the piezoelectric element flapper. CONSTITUTION: An output voltage of a DC-DC converter 37 or a voltage of a battery 38 is inputted to a DC-DC converter 39, where the voltage is converted into around DC24V. the voltage V 2 is applied to an input electric circuit comprising an up-down counter 22, a D/A converter 23 and a comparator 24 or the like and a circuit element required minimum for holding an output pneumatic pressure such as a pneumatic-electric transducer 32 or the like. Since the voltage of the battery 38 is used as a backup power supply at power failure although no voltage is inputted to the converter 39 from the converter 37, the converter 39 generates the voltage V 2 . Thus, the piezoelectric element flapper 26 holds a potential corresponding to that at power failure and the output voltage is held to a value at power failure. COPYRIGHT: (C)1985,JPO&Japio

Switch type power regulating circuit

Abstract: A buck boost type noninverting transformerless switching regulator utilizes two synchronized switches operating at either the same or different duty cycles to independently control energy storage and energy delivery from a two terminal inductor element to the output load. A wide range of output voltage is available and is continuously regulated.

State of the Art in DC-to-DC Converters

Abstract: A survey on the state of the arts in the dc-to-dc converter is presented. A number of important problems underlying the converter are classified into two categories, one is solvable by the averaging method and the other is not. In general, the converter circuit itself should be stable in order to reduce the size of the converter by making its switching frequency high. As examples of size reduction, we show three kinds of converter circuit techniques in which magnetics plays a key role. The first deals with a high frequency magnetic amplifier to suppress the current surge in high speed switching, the second with a ferro-resonant circuit driven by a high frequency inverter and the third with a high frequency converter of megahertz order which is based on a multi-vibrator. In these examples, we show that the amorphous core is effectively used for magnetic components.

High-speed bipolar logarithmic analog-to-digital converter

Abstract: A high-speed bipolar logarithmic analog-to-digital (A/D) converter outputs signed binary number proportional to the logarithm of a bipolar analog input signal. A log converter is followed by a level shifting amplifier to center the output of the log converter on a temperature compensating reference. The reference voltage from the temperature compensating reference is used by a linear A/D converter to set the end points of the converter range. A code converter follows the A/D converter if a uniform absolute value coding is desired. Limiting the number of least significant bits (LSB) used to those representing the range of usable converter operation completes the device.

Circuit arrangement for speed control of three-phase motors

Abstract: If a medium power three-phase motor (1) is supplied via a converter (1) for speed control purposes, and if a transformer (6) is connected between the converter (1) and the three-phase motor (2) for voltage matching to a medium-voltage network, the starting of the three-phase motor (2) at a very low voltage and frequency leads to saturation of the transformer (6). In order to avoid this situation, the converter (1) is connected directly to the motor (2) in the lower frequency and voltage range, bypassing the transformer (6). Once the converter (1) has reached its maximum possible voltage, the transformer is initially magnetised and is subsequently connected between the converter (1) and the three-phase motor (2), so that it is possible to increase the motor voltage further.

Static frequency changer for feeding synchronous machines

Abstract: A static frequency changer for feeding a synchronous machine and composed of a mains side static converter, a machine side static converter and a direct current intermediate circuit connected between the converters, is further provided with an additional static converter connected at the machine side in parallel opposition to the machine side static converter, and a direct voltage capacitor connected in parallel to the additional converter.