Showing papers on "Buck converter published in 1981"

DC-to-DC Voltage converter

Abstract: A DC-to-DC voltage converter is disclosed for converting the voltage from a battery to provide a power supply voltage whose value can be equal to the battery voltage multiplied by or divided by a non-integral factor, e.g. 2/3. The converter operates on the principle of capacitor charge switching, and high conversion efficiency is achieved in operation at very low levels of supply current, such as are utilized in an electronic timepiece.

Solid-state power conversion: A Fourier analysis approach to generalized transformer synthesis

Abstract: This paper deals, both from the Fourier analysis and the circuit design point of view, with a large family of electronic power converters which synthesize the assigned slow-varying waveforms via highfrequency switching, thereby needing very little reactive elements. A general condition for high-frequency synthesis applicability is given, together with a method which allows direct converter design from the desired input-output characterizations. Furthermore, a general model is introduced for high-frequency synthesis converters; as a consequence, they are characterized as two-port, multipole, time varying, linear circuit elements. Finally, as a major application example, a new AC-AC, three-to-three phase converter is introduced. The new converter displays several attractive features: sinusoidal waveforms, bidirectionality, separate control over amplitude, frequency, phase, and power factor. Moreover, depending on which side is taken as an input, it can either step up or step down the voltage. For these reasons the new converter can be regarded to as a generalized transformer.

Bi-lateral four quadrant power converter

Abstract: A power converter which supplies AC or positive or negative DC output voltage with positive or negative current while isolating the output voltage from the input power source This converter includes a pulse width modulator converts power amplitude signals to pulses of proportionate width A power driver circuit applies these pulses to a sychronous demodulator and low pass filter via a pulse transformer A low output impedance is presented to all output disturbances such that the converter can source or sink current in true four quadrant operation, including the passing of power from output to input when a load voltage exceeds the intended supply voltage

Electronic watthour meter

Abstract: An electronic watthour meter including a pulse width modulation circuit for converting a voltage signal proportional to the load voltage across the power supply lines to a pulse width duty cycle signal and a current-to-voltage converter for converting a current signal proportional to the load current across the power supply lines to a voltage signal. A multiplication circuit issues the product of the voltage signals under the control of the pulse width duty cycle signal as a pulse signal proportional to the instantaneous power consumption of the power supply lines. A filter circuit integrates the pulse signal of the multiplication circuit as an integrated voltage signal. A voltage-to-frequency converter converts the integrated voltage signal to a pulse signal proportional to the consumption power of the power supply lines. An automatic compensation circuit integrates the pulse signal of the voltage-to-frequency converter as a feedback signal to the input of the voltage-to-frequency converter thereby eliminating the inherent offset voltage caused by the pulse width modulation circuit, the current-to-voltage converter and the voltage-to-frequency converter.

Current Control Modulators: General Theory on Specific Designs

Abstract: High power distribution in continuous or pulsed mode on board application satellites has drastically complicated the design of power conditioning regulators by requiring the reliable operation with brilliant dynamic behavior of complex modular structures to satisfy their powerful loads. Current control modulators satisfy these requirements by the energy control capability. The 50-percent duty ratio instability is analyzed for each power cell configuration and canonical small signal models are given and verified in the case of an MC 2 buck regulator. The model validation is verified by application of the least square measurement technique which allows the accurate determination of any transmittance of the closed loop system.

Statistically adaptive analog to digital converter

Abstract: An improvement in an analog-to-digital converter wherein a series string of capacitors is utilized to generate reference voltages for the comparators of the converter. The digitized output of the converter is then used to control a predetermined timed discharge from a selected one of the series string of capacitors. The converter, as described, may be used in a video system as an adaptive contrast enhancement mechanism.

Switch comprising a MIS-FET operated as a source follower

Abstract: The application relates to a switch with a system operated as a source follower MIS FET. When operated as source followers MIS FET switches a "bootstrap" capacitor is used. Upon application of a control voltage of this capacitor (14) charges the gate-source capacitance (10) of the FET (2) and controls it conductive. The application provides an advantageous embodiment of the switch in front such that the auxiliary transistors used (11,12) are only charged with a voltage of the level of the gate-source voltage of the FET (2). The auxiliary transistors (11, 12) are complementary to each other. The one is parallel to the gate-source path and the other is with the bootstrap capacitor (14) and the gate-source path in series. The control electrodes of both auxiliary transistors (11, 12) are interconnected and form an input terminal of the switch. fast switching is achieved by positive feedback. The switch is applicable for example buck converter.

High-Efficiency Switching Regulator using Sub Class E Switching Mode

Abstract: A high efficiency switching dc-to-dc converter is presented, which operates at about 100 kHz with an ordinary bipolar transistor. A new converter is based on the buck converter. By positively taking advantage of the switching transistor output capacitance and the transformer leakage inductance, it is possible to realize little switching loss. When the "off" state transient response reaches zero voltage across the switching transistor, before the beginning of the "on" state, it does so with approximately zero slope. To maintain the above-mentioned operation mode, it is necessary that Ton/T of the transistor, primary inductance Lp, leakage inductance Le and the sum of the transistor output capacitance and the external capacitance are strictly selected by numerical analysis. An example is given of the new converter design to deliver a continuous power of 100 W at about 100 kHz with an overall system efficiency greater than 90 percent into a variable load. Further, unwanted noise is not produced.

Digital-to-analog converter and analog-to-digital converter with controllable bi-polar and uni-polar capability

Abstract: The digital-to-analog converter comprises an R-2R ladder network with bit controlled current steering switches connecting the legs of the ladder network to first and second current buses. First and second current-to-voltage converters are connected to the current buses respectively, the second current-to-voltage converter being connected through a switch to the input of the first current-to-voltage converter. A uni-polar/bi-polar control signal renders the switch conductive or non-conductive in accordance with the data format desired. The digital-to-analog converter is also utilized in a successive approximation analog-to-digital converter.

Cross-tied current regulator for load commutated inverter drives

Abstract: A control system for an AC motor drive including a source side converter and a load side converter coupled together by means of a DC link circuit wherein the current in the DC link circuit is controlled by either the source side converter or load side converter depending upon which converter is capable of control. This is achieved by crosstieing a signal from the normal regulating path in the source side converter control to the alternate regulating path in the load side converter control. This signal is chosen to be indicative of the source side converter controller being unable to control current, and may be derived from current error. This signal operates to alter the firing angle of the load side thyristor bridge to regulate the DC link current in the event the source side converter is unable to maintain the required current regulation.

A novel pulse delay circuit for converter control

Abstract: A new pulse delay circuit for converter control is described. The circuit is versatile in the sense that- it can be used for many converter configurations employing line and forced commutations.

Power flow direction detector

Abstract: A power flow detector for connection to power supply lines includes a phase difference-to-pulse width converter for producing pulse signals for which the pulse width corresponds to the phase difference between the load voltage and load current of the power supply lines. The output of the phase difference-to-pulse width converter is integrated and the integrated voltage is compared with a reference voltage. The power flow direction is determined by whether the integrated voltage is larger than or smaller than the reference voltage.

Device for changing the relative angular positions of operating shafts of a group electric drive

Abstract: An electric group drive having synchronous motors which are fed from a static operating converter has a second converter for use in varying the relative angle position of the motors. Provision is made for using the second converter as a start-up and braking converter. A phase shifter and memory-oriented control logic are used to control the processes.

Power-Factor Improvement of Single-Phase Converter by Means of Bias Voltage Control

Abstract: Power-factor improvement and harmonic reduction in ac line current, as well as stable and reliable operation, are very significant areas in the high-power ac-dc converter. The improvements of these characteristics of the single-phase converter may be generally difficult compared with the polyphase type. A new converter scheme suitable for the high power single-phase converter to overcome the above problems is presented. The basic configuration and principle of operation of the new converter scheme, theoretical characteristics and design indexes, and the drive system and characteristics of a dc series motor by this scheme are described. The basic principle of operation is verified and the feasibility of this converter system is demonstrated by experiments.

New DC Power Supply System

Abstract: A new DC power supply system is under development The 150V DC power supply system is suitable for digital telecommunications systems In the 150V system, since bulk DC-DC converters are necessary to supply 48V power, the bulk converter system configuration was investigated To meet the overload caused by heavy traffic congestion and to assure higher reliability than conventional power supply systems, it is effective to compose the bulk converter system of n+2 units and to install a 48V bypass feeder from a part of the 150V batteries to 48V loads in case of local exchange bulk converter system A grounding method for noise suppression in the converter output has also been investigated It clarified that a one point grounding method should be introduced and the out-put ground terminal for each converter should be grounded with a cable separately from the main distribution cable The 150V system gives 45% space saving, 35% energy saving and 30% cost reduction for the digital switching system power supply, as compared with a conventional 48V system

Device for controlling the regulating facilities in an electric high-power AC-DC converter

Abstract: The invention relates to a device particularly adapted for use with the power supply of a computer for controlling the regulating facilities in an electric high-power AC-DC converter of the power supply. This control device (D) comprises a regulation (CC) control comparator connected to the storage facilities (S) of the converter and receiving a reference voltage having a "nominal" value when the converter is normally powered by an AC network and receiving a portion of the output voltage from the converter, the output of said control comparator (CC) supplying an error signal to the regulating facilities (MR) of the converter. The control device also includes facilities (R) for supplying a variable reference voltage to the control comparator (CC) so that at the moment of recovery of the network following a cutoff, the voltage at the input of the filtering facilities (F) of the converter is, at the most, equal to the output voltage of the storage facilities (S).

Large signal design of a buck converter for high power DC/AC conversion

Abstract: The design of DC/AC power systems based on classical buck or buck-boost power cell structures implies large signal variation of the operating point duty cycle especially in the case of sine wave output.

Direct converter with a frequency-dependent current limit

Abstract: In order to protect a direct converter, formed from thyristor converters, against thermal overload, a device is provided which, at low frequencies, limits the amplitude of the current supply variable provided for controlling the converter, and, by means of the reference variable, does not enable the maximum current amplitude in accordance with the design of the converter below a minimum frequency (fmin).

Method and apparatus for enhancing the output of a log-antilog type RMS converter

Abstract: The output of a log-antilog type root-mean-square (RMS) converter (11) is enhanced by correcting it for nonlinearities in the AC/DC transfer characteristic of the converter (11). First, preselected positive and negative DC voltages near the upper and lower ends of the range of the RMS converter (11) are applied to the RMS converter (11) and the output of the converter (11) is measured by a voltage measuring instrument (15) for each applied voltage. The applied and measured voltage values are used to determine the positive and negative gain (G) and offset voltage (Vo) characteristics of the RMS converter (11). The characteristic information is used to correct (e.g., enhance) the output of the RMS converter (11) when AC voltages falling within the range of the converter (11) are later applied. The same procedure is followed for each range of the RMS converter (11), if the RMS converter (11) has multiple ranges. Further enhancement is provided by correcting for gain errors resulting from crest factor variations. Crest factor variation enhancement is provided by applying preselected square waves to the converter (11) and measuring the output of the converter (11). The measured output voltages are utilized to determine the positive and negative gain crest factor correction constants, which are used to correct the positive and negative gain characteristics of the RMS converter (11).

Numerical control devices

Abstract: A numerical controller equipped with a power source voltage diagnostic function, in which there are provided an A-D converter (AD) for converting into a digital quantity the output voltage from a DC power source used in the numerical controller and a processor (CPU) for reading out the output from the A-D converter (AD) to perform a predetermined operation for checking the power source voltage.

Transistor converter circuit.

Abstract: 1. Transistor inverted converter circuit comprising a transformer (11; 111) having a primary winding (11a; 111a) which can be connected to a d.c. voltage source (1; 101) in series with the emitter-collector path of a transistor (4, 5; 105), a secondary winding (11b; 111b) to which a load (15; 115) can be connected, and a control winding (6, 162) which ist connected by one terminal to the base of the transistor (4, 5; 105) and which is connected by another terminal to the emitter of the transistor (4, 5; 105) by way of a diode means (base-emitter path of 5 or 4; diode 142), and which is provided between the two terminals with a tapping (6d; c) which is connected to a terminal of a biasing capacitor (9, 109), the other terminal of which is connected by way of a resistor (10; 110) to the emitter of the transistor (4, 5; 105), further comprising a commutating capacitor (12; 112) which is part of an oscillator circuit determining the frequency of the converter circuit, and a charging circuit having a diode (7, 8; 107) for charging the biasing capacitor (9, 109) to a d.c. control voltage which is of a polarity for conduction by the transistor (4, 5; 105), characterised in that the primary winding of the transformer (11, 111) is connected to the d.c. voltage input by way of a choke (2; 102), that the charging circuit is a closed circuit which is formed by the diode (7, 8; 107) serving as rectifier means, the biasing capacitor (9, 109) and at least a part (6a-6d, 6b-d; a-c) of the control winding (6; 162), and that the resistor (10; 111) which is connected to the biasing capacitor (9; 109) is only part of the control circuit (Figure 1; Figure 3).