Showing papers on "Flyback 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.

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.

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.

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.

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

Selection of snubbers and clamps to optimize the design of transistor switching converters

Abstract: In power transistor switching circuits, shunt snubbers (dv/dt limiting capacitors) are often used to reduce the turn-off switching loss or prevent reverse-biased second breakdown. Similarly, series snubbers (di/dt limiting inductors) are used to reduce the turn-on switching loss or prevent forward- biased second breakdown. In both cases, energy is stored in the reactive element of the snubber and dissipated during its discharge. If the circuit includes a transformer, a voltage clamp across the transistor may be needed to absorb the energy trapped in the leakage inductance. The action of these typical snubber and clamp arrangements is analyzed and applied to optimize the design of a flyback converter used as a battery charger.

Pulsed power supply system

Abstract: A square wave clock signal is coupled to a transistor, the output of which is transformer coupled to the base of a driver transistor. The conducting of the driver transistor will cause an increase in the current through the primary of a flyback transformer, thereby resulting in a relatively small negative going voltage potential being induced therein. When the driver transistor is caused to go into a non-conducting state, due to the signal on the base, the decrease in current through the primary of the flyback transformer in relation to the change in time is large, thereby inducing a large positive voltage potential across the primary. The induced voltage is stepped-up by the flyback transformer where the negative overring portion is rectified and regulated to supply a potential to the grid of an ion source. The positive voltage pulse is coupled into a voltage multiplier circuit, the output of which is connected between the ion source anode and cathode of an accelerator tube used for producing fast neutrons from the D-T reaction. Additionally, a firing reference signal is coupled from the driver transistor to the radioactivity logging instrument to provide a timing signal used to enable the detecting circuitry therein for measuring radiations returning from the formations as a result of fast neutrons being emitted by the ion source.

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.

Design of transistor switching converters

Abstract: In power transistor switching circuits, shunt snubbers (dv/dt limiting capacitors) are often used to reduce the turn-off switching loss or prevent reverse-biased second breakdown. Similarly, series snubbers (di/dt limiting inductors) are used to reduce the turn-on switching loss or prevent for­ ward-biased second breakdown. In both cases, energy is stored in the reactive element of the snubber and dissipated during its discharge. If the circuit includes a transformer, a voltage clamp across the transistor may be needed to absorb the energy trapped in the leakage inductance. The action of these typical snubber and clamp arrange­ ments is analyzed and applied to optimize the de­ sign of a flyback converter used as a battery charger.

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.

Multi-spark CD ignition

Abstract: An improved multi-spark capacitor discharge (CD) ignition having independent circuits for charging and discharging the main capacitor, a flyback DC to DC converter, and an inductive filter interposed between the ignition coil and the main capacitor on one side, and the charging transformer on the other side.

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.

DC power supply - has ripple across load reduced by using saturable inductor in series with battery across load

Abstract: The dc power supply has an ac/dc converter (12) connected at its input to a 3-phase supply (R,S,T) and at its output via an LC filter (2) to the outgoing dc supply lines lead (5) The 3-phase supply is coupled to the converter via a transformer (11) A battery (3) is connected in series with a saturated inductor (4) across the load The inductor is designed such that it is driven into saturation above and below the average of the ripple of the dc voltage across the load The amplitude of the current needed to attain saturation is less than the max admissible ac superimposed on the battery's charging current

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.

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.