Showing papers on "Buck–boost converter published in 1979"

Buck/boost regulator

Abstract: A voltage regulated DC to DC converter is disclosed which is operable over a wide range of input voltage including voltages greater or less than the desired output voltage The converter uses an inductor and a capacitor as storage elements, the inductor being composed of two windings having a common junction A transformer having a center tap connected to the common junction of the two windings of the inductor is connected at either end of its winding to ground through controlled switches One winding of the inductor and either end of the transformer winding are connected by respective power diodes to the capacitor which supplies the output voltage to a load The other winding of the inductor is connected to a fourth power diode as a clamping diode Input voltage is supplied to the inductor through a third controlled switch A pulse width modulator connected to the output of the converter alternately closes and opens the switches connected to either end of the transformer winding and also closes the switch supplying input voltage to the inductor each time either of the switches connected to the ends of the transformer winding are closed The duty cycle of the closing and opening of the several switches is adjusted by the pulse modulator to regulate the output voltage

A Controllable 45-kW Current Source for DC Machines

Abstract: A new type of dc converter for the drive and control of a 45-kW traction motor in single quadrant operation with an efficiency of 96 percent is presented. An improvement of the converter's reliability is due to the natural termination of thyristor currents, the positive confinement of the maximum momentary current and voltage stresses in the components below preset levels, and the low power dissipation in these components, supported by a definite protection philosophy. The high converter efficiency is attained at full power operation with an internal frequency of 10 kHz. The input impedance maintains its resistive character for all conditions of operation. The output port is characterized as a voltage-limited current source. Test data of an experimental model conclude the presentation of the converter's functional philosophy.

Power Factor Improvement with a Modified Phase-Controlled Converter

Abstract: A modified phase-commutated converter with an improved power factor (PF) is presented and is analyzed for both rectifying and inverting modes. The optimal power factor firing control is formulated while taking into account commutation overlaps. Different modes of converter operation are identified and are analyzed in terms of reactive power requirements, power factor, and harmonic distortion on both ac and dc sides. The results are used to compare critically the new converter with a conventional six-pulse bridge.

Comparison of multiρle-output DC-DC converters using cross regulation

Abstract: A new multiple-output dc-dc converter is analyzed, in which the cross regulation is performed by the energy-storage reactor as well as the transformer. The steady state and the dynamic characteristics of this converter is compared both theoretically and experimentally with those of the conventional one composed of the step-up-down type circuit. As the results of comparative analysis, it is revealed that this new converter is superior to the conventional one in the steady state and the dynamic performances. Further, it is demonstrated experimentally that the cross regulation performance of this new multiple-output converter is less affected by the leakage flux in the energy-storage reactor, and also that this converter is very useful as a preregulator for the continuous series regulator in cases requiring a high degree of regulation of the multiple-output voltages.

Control method and system for an high voltage direct current system

Abstract: A HVDC system has two converter stations, each of which has two converters connected in cascade to operate as a rectifier or an inverter and the stations are connected through a d.c. power transmission line to each other and are connected to respective a.c. power sources through the a.c. power transmission lines. Each converter is controlled depending on the difference between a current reference for the HVDC system and an actual current flowing in the HVDC system when the converter operates as a rectifier, and controlled depending on the output of the constant margin angle control circuit when the converter operates as an inverter. When the converter operation condition is changed, i.e. another converter operates in addition to the converters in operation or the direction of power transmission in the HVDC system is changed, the current reference for the HVDC system is reduced depending on the d.c. voltage during a predetermined period.

Electrically variable impedance circuit

Abstract: An electrically variable impedance circuit in which a voltage-current converter circuit (3) is provided to produce a current (I') having a megnitude corresponding to an instantaneous input signal potential (v) applied to an input terminal (1) and a current variation of the vottage-current converter circuit is fed back to the input terminal (1), the current variation being controlled by a control signal (Vc) to vary the circuit impedance seen from the Input terminal (1). In order to expand the range of linesrity in impedance, the voltage-current converter is so arranged that the varying component of its output current is linsariy proportional to the inatan- taneous input signal potendial (v). and a current converter circuit (4) is provided which linearly converts the output current of the voltage-current converter circuit and whose output is coupled to the input terminal (1). The current converter circuit (4) is comprised of a PN junction (51) which develops a voltage which is the logarithm of the output current of the voltage-current converter (3) and a transistor (81) between the base and emitter of which is spplied the voltage developed by the PN junction (5 1 ) to produce a current which is the exponential of the voltage developed by the PN junction. (Fig. 1)

Autocalibration of compressed A/D converter

Abstract: An analog-to-digital converter system is disclosed in which the amplitude of the signal is compressed by means including a logging means prior to an analog-to-digital converter. Reference signals of known values are applied to the logging means and their values at the output of the converter are used to determine a linearity factor which is applied to a multiplier coupled to the output of the converter. The amplitude of one of the reference signals at the output of the multiplier is compared with what it should be and the difference is added by an adder at the output of the multiplier.

Frequency converter and its controlling method

Abstract: PURPOSE: To enhance the power factor of a power supply by regenerative control employing a voltage-type pulse-width modulation converting means as a converter on the power-supply side with converts AC voltages to DC and as an inverter on the motor side which supplies variable-voltage variable-frequency voltage to a motor. CONSTITUTION: A DC input current of an inverter 2 flows from a converter 5 to an inverter 2 in the case of a reverse-conversion operation, and from the inverter 2 to the converter 5 in the case of forward-conversion operation. In both cases, the voltage of a capacitor 15 is controlled at a constant value, and the DC output current from the converter 5 is always balanced with the DC input current of the inverter 2. That is, the operation of the inverter 2 and that of the converter 5 are opposite each other. Since both the converter and the inverter are sonstituted by a PWM converting means, the motor current forms a sinusoidal wave, torque ripples are not generated, and the harmonic waves of the power supply are not generated either. COPYRIGHT: (C)1980,JPO&Japio

Instrument for use with an electrochemical cell

Abstract: An improved instrument for use with an electrochemical cell that provides a system having enhanced stability and increased bandwidth. The instrument includes a voltage to current converter which drives the cell. The current output of the voltage to current converter is linearly proportional to the differential voltage input. The voltage to current converter drives the cell in both the potentiostatic mode and in the galvanostatic mode of operation.

Analogue to digital converter channels

Abstract: This is an analogue to digital converter channel including an analogue multiplexer, a switched gain amplifier, a mode amplifier, a sample and hold stage, and an analogue to digital converter. Off-set errors can be precalculated and then corrected for by switching the input to the amplifiers to null, and storing the output from the converter, and the amplified output from the gain amplifier respectively at `X` and `Y` and then combining those stored off-set error signals at an adding circuit at the input to the converter during a subsequent analogue to digital conversion.

Process of pulse duration modulation of a multi-phase converter

Abstract: A process of pulse duration modulation for improved voltage and frequency efficiency of a multi-phase converter. The sum of the time dependent voltage of a load phase and of an auxiliary time dependent voltage is formed, wherein the auxiliary time dependent voltage is the same for all converter phases. The pulse duration of the output voltage of each converter phase is modulated with said voltage sum.

Modeling and analysis of switching dc-to-dc converter in constant-frequency current-programmed mode

Abstract: An analysis of dc-to-dc switching converters in constant-frequency current-programmed continous conduction mode is performed, and leads to two significant resuslts. The first is that a ramp function, used to eliminate a potential instability, can be chosen uniquely to assure both stability and the fastest possible transient response of the programmed current. The second is the development of an extension of the state-space averaging technique by means of which both the input and output small-signal properties of any such converter may be accurately represented by a linear small-signal equivalent-circuit model. The model is presented and experimentally verified for the cuk converter and for the conventional buck, boost, and buck-boost converters. All models exhibit basically a one-pole control-to-output transfer fuction response.

Circuit for monitoring the current distribution in parallel-connected converter branches

Abstract: A circuit arrangement for monitoring the current inbalance in two parallel-connected converter branches, each of which includes at least two series-connected converter valves. The anodes and cathodes, respectively, of adjacent converter valves in a given branch are connected together via cross-connections containing current transformers. A differential current transformer is provided at the output junction point of the two converter branches. Starting with the output signal of the differential current transformer, the exact current misdistribution for each adjacent converter valve pair is determined via summing amplifiers by adding the currents of the transverse transformers. A protective measure is triggered if a current misdistribution occurs.

Recirculating RMS AC conversion method and apparatus

Abstract: RECIRCULATING RMS AC CONVERSION METHOD AND APPARATUS Abstract of the Disclosure A signal whose RMS value is to be accurately determined is first converted into DC form by a relatively inaccurate RMS converter, such as a thermal RMS converter. The result is a first converter signal (Y1), which is stored for recirculation in a suitable storage device, such as a sample and hold circuit. The first converter signal is also doubled (2Y1) and stored. Thereafter the first converter signal stored in the storage device is recirculated to the converter to create a second converter signal (Y2). Then, the second converter signal is subtracted from the doubled first converter signal (2Y1 - Y2) to produce a highly accurate RMS output signal.

Analysis and Design of an Adaptive Multi-Loop Controlled Two Winding Buck/Boost Regulator

Abstract: Small signal low frequency linear average model is derived for a multi-loop controlled two-winding buck/boost converter employing average techniques and the describing function method. The model reveals that a well-designed multi-loop control can provide a second-order zero adaptive to output filter parameter changes due to component tolerances, temperature changes, aging, and the effect of duty cycle modulation. It also can provide stabilization effect by shifting the positive zero to the left-half S-plane. Design quidelines are formulated to optimize regulator-loop dependent characteristics.

Digital sample and hold circuit

Abstract: A sample and hold circuit for an automotive speed control system is disclosed which includes a non-monotonic digital-to-analog converter suitable for fabrication as a highly dense monolithic circuit. The non-monotonic digital-to-analog converter precludes the occurrence of large positive errors in the analog output value, which might be caused by tolerance errors in the ratio of binary-weighted currents within the digital-to-analog converter, by including offsetting negative errors within the design of the digital-to-analog converter.

Gated precision offset circuit for a digital meter having a dual slope analog-to-digital converter

Abstract: An offset circuit for use in providing an offset signal to an analog-to-digital converter. The analog-to-digital converter has an integrator for performing signal integrate operations and is connected to a digital display. The offset circuit is gated to provide a variable offset current directly to the integrator of the analog-to-digital converter, thereby eliminating adverse loading effects on the high input impedance of the analog-to-digital converter.

Multiple-bridge, three-phase converter arrangement including voltage harmonics cancellation

Abstract: All harmonics of an order less than (6 N-1) are cancelled from the fundamental signal presented in each output phase of the three-phase converter as the sum of corresponding phase angle fundamental signals from an N number of converter bridges, where N is a non-power of two.

A 7b A/D converter

Abstract: A 7b two-step parallel A/D converter using a quantizer-subtractor circuit will be discussed. Double layer metalization has been used to reduce the die size to 2.4 × 2.5mm. Analog input signals up to 5MHz can be digitally sampled with sampling frequencies up to 50MHz.

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

Abstract: An analysis technique is presented which permits the designer to explore the start-up transient of a dc-to-dc converter when it is powered by a current-limited source. The current versus voltage characteristics of the source are superimposed upon those of the dc-to-dc converter. By noting the nature of the intersectition of these curves in the voltage-current plane, we are able to predict whether or not the converter is able to start up while powering a specified load.

A Buck/Boost Power System for Telecom Australia

Abstract: The Buck/Boost Power System is a new telephone power supply capable of providing a fully regulated output under either a.c. mains operation or battery operation. This article discusses design objectives, principles and operation, technical problems to be overcome and economic aspects of the Buck/Boost System. It also describes the first large installation based on the buck/boost system for powering a stored programme controlled (SPC) trunk switching centre, and indicates future applications of this new generation of power equipment.

Electrical energy converter using solid state switching - includes fast acting regulator which assists harmonic suppression and has two stages of control

Abstract: The modified regulator is used for an energy converter, e.g., DC to DC or DC to AC, employing semiconductor switching elements. It has two stages of control. The basic timing signal is compared with converter output voltage, and then with a quantity directly proportional to output current. The resultant is used to control the gate pulses to the converter. The circuit ensures close copying of the basic timing signal by the converter. A frequency limit may be applied to the gate pulse rate. The regulator is intended to reduce harmonics in the output.

MP-A9 a high-speed superconducting A/D converter

Abstract: device has been shown to have high charge e f f i~ i ency .~ This device differs from a conventional buried-channel CCD in yet another significant aspect. Instead of the p-substrate, n-active layer arrangement typically used in buried-channel CCD technology, this device employs a semi-insulating substrate and ntype active layer. The semi-insulating substrate has important implications for high-speed applications since stray capacitance is reduced substantially with the consequence that power dissipation jn the clock drivers (Pd = cv2f) is reduced accordingly. Also, the semi-insulating substrate eliminated the need for a separate channel stop. The first device described by Deyhimi e t aL2y4 was a 30-gate device and served to prove the concept of the Schottkybarrier gate, buriedchannel CCD, and to characterize it with respect t o transfer efficiency, linearity, and floating gate capability. A new device has been fabricated and very recently operated and transfer efficency has been verified to be >0.999 per transfer. ~ This device employs 4.5 pm X 100 pm transfer gates (separated by I-vm gaps), as well as an on-chip reset amplifier. A 131-gate and a 259-gate version of this device have been successfully operated. The CCD transfer gates are connected in a 4-phase configuration. The active layer of the device is n-type with ND = 1 X 10 l6 /cm3. The device channel is isolated with a mesa etch and the electrode interconnection patterns are printed directly on the semi-insulating substrate. The device employs two-level metallization isolated by a plasma-deposited silicon-nitride. The 13 1-gate version of this device has been operated at up to 500 MHz. The results of transfer efficiency measurements will be reported.

Electronic instrument amplifier

Abstract: The amplifier is intended for use in situations where a considerable distance separates the instrument (for example a piezo-electric transducer) to be monitored and the control room. The amplifier comprises a charge/current converter for converting the charge output of the instrument into a current signal, the charge/current converter being connected to operate as a high impedance current source, a current/voltage converter and a connecting cable connecting the current output of the charge current converter to the input of the current/voltage converter.

Dc-dc converter for plurality of output

Abstract: PURPOSE:To obtain a plurality of stabilized DC voltage whose polarities and the voltage values are different, by connecting a step-down converter and a step-up and -down converter to the output of a DC-DC converter in parallel. CONSTITUTION:In the step-down converter, the output voltage of a transformer T1 is VNT1, the conducting time of a transistor Q2 is tON2, and the period is T. Then, the output voltage of a terminal TM1 is VTM1=VNT1XtON2/T. By controlling the conducting time of Q2, the specified stabilized voltage can be obtained. In the step-down and -up converter, the output voltage of a terminal TM2 is VTM2=VNT1XtON3/tOFF3, where the conducting time of a transistor Q3 is tON3 and the nonconducting time is tOFF3. By controlling the ratio of opening and closing time, the specified stabilized voltage can be obtained. The polarity of said voltage is opposite to that of the voltage generated in the output winding N4 at the time Q3 is conducting. In both converters, the appropriate output voltages whose polarities are different can be obtained.

High density analog-to-digital converter

Abstract: Combining integrated injection logic (I 2 L) and linear circuitry permits fabrication of a highly dense analog-to-digital (A-to-D) converter. The heart of the A-to-D converter is a linear-I 2 L plurality of high density variable current sources which are proportional to each other. These variable current sources, when used in combination with I 2 L constant current sources and current sensing means, provide a highly compact A-to-D converter.

A new concept of thermionic converter

Abstract: The parameters of a new type of thermionic converter, which has a number of concentric electrodes, are computed. The obtained theoretical efficiency of this new type of converter is close to the efficiency of the ideal thermionic diode converter. The results obtained are explained by the reduction of the radiation loss from the emitter due to the electrode configuration. Efficiencies as high as 20% are expected from this type of converter, which is now being constructed.

Energy-storage and transfer mechanism in the reactor of new multiple-output DC-DC converter

Abstract: The energy-storage and transfer mechanism in the reactor of new multiple-output dc-dc converter is examined to define the output characteristics of this converter. In this converter, only one output voltage is regulated directly by the feedback control, and all others are slave to it; the regulation of all the other outputs is performed by using the magnetic coupling among the windings of the reactor. The operation of this converter is divided broadly into two major modes. In one mode, this converter has advantages over the conventional ones in the steady-state and dynamic characteristics. But this converter, in the other mode, has a defect that extraordinary phenomena arise. With the increase in the sum of the slave output powers, the output voltage within the feedback loops tends to increase extraordinarily and also all the slave output voltages decrease inversely. Examining the energy-storage and transfer mechanism in the reactor of this converter, the critical condition is derived to define the boundary between the two operation modes, and the output characteristics is clarified in each mode.