Showing papers on "Forward converter published in 1979"

Power source system

Abstract: A power source system, which comprises a converter for converting AC power on an AC bus into DC power, a damped filter connected between the AC bus and ground and including a capacitor and an inductor, a diode-rectifying circuit for taking out and rectifying fundamental and harmonic waves produced across the inductor in the damped filter and a circuit for connecting a DC output circuit in the diode-rectifying circuit in series with a DC output circuit in said converter, and in which the rectified output is regeneratively added to the output of the converter.

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.

Battery package with dc to dc converter

Abstract: A battery package having a casing which contains at least one electrochemical cell electrically connected to a DC to DC converter. A pair of electrical connections are located on the casing to electrically connect the battery package to a load. The converter conducts and the cell discharges only when a load is present across the electrical connection.

DC-DC Converter for charging a battery by means of a solar cell

Abstract: A DC-DC converter is described of the blocking oscillator type, for charging a battery from a solar cell. The use of a field effect transistor enables the oscillation to be started by the voltage from a single solar cell, even if the battery is fully exhausted. The overall efficiency of the circuit is improved by the use of the base-emitter junction of the switching transistor of the converter as rectifying element for the battery charging current.

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.

N Phase digital inverter

Abstract: An N phase digital inverter for converting an input DC voltage level to an output DC voltage level interposes between the input and output terminals thereof a plurality of N parallel switching circuits, each switching circuit thereof comprising in series a power switch and a transformer. The output of each transformer is coupled through a diode to a common point for filtering to generate the output DC voltage. The output DC voltage is sensed and fed to a logic generator for generating a ring sequence of pulses which activate sequentially each power switch in the plurality thereof. The logic generator controls the ratio of pulse time ON divided by pulse time ON plus pulse time OFF to maintain a desired level of output DC voltage.

Dc power transmission control

Abstract: OF THE DISCLOSURE A pair of thyristor converters are connected by a DC power transmission line, and their AC terminals are connected through tapped transformers to AC systems respectively. The output signal of a constant-current circuit in a converter control unit associated with the forward converter is selected to control the gate of the forward converter, while the output signal of a constant-voltage circuit in a converter control unit associated with the reverse converter is selected to control the gate of the reverse converter. When the reactive power is to be controlled, a reactive power signal is applied for the gate control. A voltage limit indication circuit in each control unit receives the AC terminal voltage e2 of the transformer and the DC current Id so as to increase the control angle limit with a decrease in the values of e2 and Id. When the control advance angle or control delay angle determined by the output signals of the control circuits is larger than the control angle limit, this angle is limited to the control angle limit. When the reactive power is to be controlled, the tap position of either transformer is lowered to decrease e2 and to increase the control angle limit thereby widening the controllable range of the reactive power. During the start-stop stage or during the protective operation, the output of the voltage limit indication circuit in each control unit is inhibited to permit free variations of the control angle.

Transformerless fast current limiter with symetry correction for a switched-mode power supply

Abstract: A switched mode power supply employs a pulse width modulation controlled DC-to-DC converter to change a first voltage from a source of DC power into a regulated power source providing direct current at a second DC voltage. A transformerless current-sensing device is adapted for connection in the path between said source and said converter and provides a control signal which is representative of the current flowing in said path. A current-limiter control circuit is responsive to said control signal and provides an enabling output state when the sensed-current exceeds a predetermined value. The enabling state overrides the pulse width modulator control and inhibits the converter, thus terminating the output pulse when the sensed current exceeds said predetermined value.

Rotary phase converter

Abstract: A rotary phase converter for connection to a single-phase a.c. power source and adapted to supply polyphase current to a polyphase electrical load. The converter includes a dynamoelectric machine having at least three stator windings and at least first, second and third output terminals, an autotransformer and at least one capacitor. The stator windings of the dynamoelectric machine are oriented symmetrically with respect to each other both physically and electrically and each has a substantially equal number of active turns. The first and second terminals of the dynamoelectric machine are adapted to be connected to the single-phase a.c. power source and they are also outputs of the converter. The autotransformer is connected across the second and third terminals and has at least one tap positioned intermediate the ends thereof to serve as an output of the converter. The capacitor is connected between the first output terminal and the autotransformer tap serving as a converter output. The currents supplied from the converter outputs to the phases of the polyphase load are maintained substantially balanced at full load.

Clock-controlled DC converter

Abstract: A clock-controlled dc converter is provided in integrated semiconductor MOS technology and serves the supply voltage of integrated MOS circuits, particularly dynamic memories. The converter comprises a clock pulse generator having two outputs, supplying sequences of clock pulses which are inverted with respect to one another, which pulses are connected to the two clock pulse inputs of a first pulse level shifter. The first pulse level shifter comprises a bistable flip-flop lying at a supply potential, and which is switched as a level shifter. The two outputs of the first level shifter are connected, on the one hand, to the output of a voltage converter by way of the source-drain circuit of a respective field effect transistor. On the other hand, the two outputs are connected to the supply input of a respective pulse voltage doubler, which are in turn directly charged by a respective output of the clock pulse generator. The two pulse voltage doublers supply the clock pulse supply for a second pulse level shifter, likewise constructed as a bistable flip-flop, by way of the two outputs of which the connection between the outputs of the first level shifter and the output of the voltage comparator is controlled. The doubled supply voltage appears at the output of the voltage converter.

Booster-inverter power supply circuit

Abstract: The invention is a booster-inverter power supply circuit for providing a regulated, inverted DC output. It is made up of a conventional booster-regulator power supply circuit and improved by the addition of an inverter circuit. The conventional booster-regulator circuit includes an unregulated DC input, a booster choke for receiving the DC input, a switch for controlling the booster choke, a voltage to pulsewidth control connected to the switch for controlling the switch, an AC to DC converter for providing a DC to the voltage to pulsewidth control, and an output circuit having an output diode. The circuit is improved by the addition of the inverter circuit having an inverter transformer and a voltage control circuit. The inverter transformer is connected at one end to the switch, the booster choke, and the output diode. The switch controls the voltage on the inverter transformer. The output of the inverter transformer is a regulated AC output fed to the AC to DC converter. The voltage control circuit is connected to the other end of said inverter transformer for maintaining a constant voltage.

Regulated variable frequency DC/DC converter

Abstract: This circuit converts a DC voltage of one value to a regulated DC voltage of another value. The circuitry includes a variable frequency clock controlled by an error voltage derived from the converter output. A pulse of constant length is produced for each cycle of the clock. Logic circuitry is arranged to alternately feed these constant length pulses to opposite sides of a push-pull power amplifier, the output of which is rectified and filtered to form the converter output.

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.

On the precise regulation of multiple outputs in a DC-DC converter with an energy-storage reactor

Abstract: In order to regulate multiple output voltages in a dc-dc converter, the crossregulation technique is usually used. However, due to the leakage inductances of transformer and the resistance components of the circuit, there appear the regulation errors in the cross-regulated outputs. This paper presents a new method to compensate the cross-regulation errors and regulate all of the multiple output voltages precisely. This precise regulation is performed by making use of an auxiliary switch in each output circuit, and therefore the additional power loss is not wasted in principle. Further, from the analysis of this new converter circuit, two different operation modes are clarified.

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.

Combined current and voltage converter for a compressed-gas insulated metal-enclosed high voltage installation

Abstract: The invention relates to a combined current and voltage converter for metal-enclosed high-voltage installations with compressed-gas filling. In order to be able to avoid any passages for the connecting leads through the housing (1, 2), the electrode of the capacitive voltage converter part consists of an intermediate element (3) inserted into the housing in an insulated and gas pressure-tight manner. The intermediate element (3) has on its outside a layer of insulating material (9) and on top of this a metal layer (10). The whole (3, 9, 10) forms a support body for current converter cores (11) surrounded by secondary windings. The low-voltage capacity between the intermediate element (3) and the metal layer (10) is fed to an electronic measuring amplifier (14) via a screened measuring cable (12/12a). The current converter cores (11) are protected mechanically by a sheath tube (16), the latter simultaneously conducting housing currents. FIG. 1.

DC Motor control system

Abstract: A DC motor control system which has means for detecting the rise and fall of a drive command signal to generate an ON ACCELERATION/DECELERATION signal and means for generating a current limit signal for driving a DC motor by the ON ACCELERATION/DECELERATION signal to produce a rated output and for driving the DC motor to produce an output 1/n times the rated output when the DC motor is switched from an acceleration state to a stationary state. When the DC motor is accelerated or decelerated by the drive command signal, a current for obtaining the rated output is applied to the armature of the DC motor and, in the stationary state, even when a load on the DC motor is maximum a current for obtaining an output 1/n times the rated output is applied to the armature of the DC motor to reduce the output of the large-output DC motor, thereby providing an enlarged constant output DC motor range.

Voltage converter apparatus having output regulating means

Abstract: Voltage converter apparatus is disclosed having circuitry for regulating the output voltage to maintain it at a regulated value. Use is made of switching devices that switch between their alternative states in a cyclic manner and at a particular frequency which is determined by the circuit constants. An inductance is provided for modifying the waveform of the current fed to the output transformer, so that at certain periods of the cycle there is a lesser contribution to the integrated output--i.e., the output is not a true 1:1 square wave. Then, by changing the switching intervals, the integrated output can be controlled. A current transformer is provided for sensing current changes occurring in the output transformer, and a short circuit arrangement is provided for short circuiting a control winding of the converting transformer to control the instants of switching of the switching devices.

A high repetition rate power pulse generator

Abstract: Disclosed is a class of power converters which extract electric energy from a source of A.C. or D.C. power and transform this energy to a desired and closely controlled voltage level for use by a pulse demanding load such as a pulsed radar or laser system. The converter eliminates the need for a D.C. link anywhere in the converter system and the need for low frequency power filters. The invention includes a transformerless circuit with galvanic isolation between system input and output terminals and controlled voltage scaling.

Interrupt signal generating means for data processor

Abstract: An interrupt signal generating means comprising a digital-to-analog (D/A) converter and means for supplying to said D/A converter a series of binary numbers at least some of which point to service subroutines in a data processor, and when converted to dc voltages by the D/A converter have values which are equal to dc voltages originating in various peripheral devices which indicate a need for servicing by certain ones of the processor subroutines. A plurality of voltage comparators compare the dc output of the D/A converter with the condition indicating voltages generated by the peripheral devices and when equality of dc voltages occurs on the inputs of a given voltage comparator, an interrupt signal is generated and supplied to the processor which then accesses the subroutine pointed to by the corresponding binary number.

AC Motor drive system having clamped command error signal

Abstract: Disclosed is a three phase AC motor drive system wherein a variable frequency variable magnitude AC current is fed to an AC motor load from a thyristor controlled DC to AC inverter which is supplied from a thyristor controlled AC to DC converter by way of a DC link including an inductor. The DC load current is commanded to rise at a rate limited by the difference between the output voltage of the converter and the input voltage to the inverter which voltage appears across the inductor. As a result of the inherent commutation transport lag encountered for commands in the negative direction, an error signal clamp is placed in a feedback signal path controlling the AC to DC converter for limiting the command for changes in the positive direction thereby providing a system response in the positive direction which is more nearly like the response in the negative direction.

Current limiter for switched DC-to-DC converter

Abstract: A switched DC-to-DC converter in a power supply is powered by input line current from an external power source and driven by voltage pulses from a variable duty cycle pulse width modulator for converting a DC input voltage to a DC supply voltage of a different value that is applied to a load impedance. A comparator monitors the supply voltage for producing an error voltage that biases the modulator for adjusting the width of the voltage pulses, and thus the duty cycle of the converter, for maintaining the supply voltage relatively constant. An RC circuit integrates the voltage pulses for producing an indication of the average value thereof, which is directly related to the value of line current drawn by the converter. When the average value of voltage pulses exceeds a reference voltage, the value of bias voltage is limited for establishing the maximum width of voltage pulses and duty cycle of the converter, and thereby limit the maximum line current drawn by the power supply.

DC/DC Stabilized voltage converter unit

Abstract: In a DC/DC stabilized voltage converting unit having a series circuit including an input filter, a converter stage having a control input and an output filter, the improvement comprising: a control stage having an output connected to the control input; a voltage regulating circuit receptive of an output of the output filter and having an output applied to the control stage; an anti-overvoltage and anti-overcurrent stage receptive of an output of the converter stage and having an output applied to the control stage; a voltage converter chain coupling circuit for effecting the linking of units in a chain; an internal monitoring and commutating circuit connected between the voltage regulating circuit and the control stage for surveying the outputs of the converter stage; a visually and electrically signalling alarm circuit receptive of the outputs of the output filter and having the outputs thereof applied to the chain coupling circuit; and wherein the chain coupling circuit includes a first input for linking to one pole of a power supply source, a coupling terminal connectable to said one pole of the power supply source, a third input for connecting to the coupling terminal of the next chain coupling circuit in the chain, first and second outputs connected to the input filter and a third output connected to the control stage.

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.

Practical design considerations of a multi-output CUK converter

Abstract: An experimental high frequency three output dc-dc converter design is presented in circuit detail, emphasizing the practical design needs of its contemporaty optimum topology ('CUK) output stages. Power component selection criteria are also given along with suitable load protection methods against output voltage reversals at turn-on. Inductor coupling criteria for ripple current reductions at input/output ports are develop including an alternate method for external tuning inductance insertion. Results of corresponding empirical evaluations of a 200KHz, 55-W representative design are discussed.

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.