Showing papers on "Rectifier published in 1981"

Unity power factor switching regulator

Abstract: A single or multiphase boost chopper regulator operating with unity power factor, for use such as to charge a battery is comprised of a power section for converting single or multiphase line energy into recharge energy including a rectifier (10), one inductor (L 1 ) and one chopper (Q 1 ) for each chopper phase for presenting a load (battery) with a current output, and duty cycle control means (16) for each chopper to control the average inductor current over each period of the chopper, and a sensing and control section including means (20) for sensing at least one load parameter, means (22) for producing a current command signal as a function of said parameter, means (26) for producing a feedback signal as a function of said current command signal and the average rectifier voltage output over each period of the chopper, means (28) for sensing current through said inductor, means (18) for comparing said feedback signal with said sensed current to produce, in response to a difference, a control signal applied to the duty cycle control means, whereby the average inductor current is proportionate to the average rectifier voltage output over each period of the chopper, and instantaneous line current is thereby maintained proportionate to the instantaneous line voltage, thus achieving a unity power factor. The boost chopper is comprised of a plurality of converters connected in parallel and operated in staggered phase. For optimal harmonic suppression, the duty cycles of the switching converters are evenly spaced, and by negative coupling between pairs 180° out-of-phase, peak currents through the switches can be reduced while reducing the inductor size and mass.

Transformerless battery controlled battery charger

Abstract: A lightweight, efficient, transformerless battery-charging system especially for use with electric vehicles, wherein a switching regulator stores only a fraction of the energy in each charging pulse, and much of the charging energy is supplied directly from the powerline and never stored in the charger. Major components include an overload and ground-fault protective current interruptor, an RF interference filter and line rectifier, and a switching regulator capable of maintaining a constant-current constant-voltage output, providing controlled input current throughout the AC cycle and including means for external shutdown.

Optimum Input and Output Filters for a Single-Phase Rectifier Power Supply

Abstract: The ``optimum'' output filter inductance Lf and the input filter capacitor Ci for a single-phase uncontrolled bridge rectifier employed for low power de-to-dc converters or inverters is established. The filter Ci is optimized to obtain maximum input power factor, minimum filter inductance, and minimum output dc voltage regulation. A design example is provided and theoretical results have been verified on an experimental model.

Alternator assembly having a rectifier device in thermal contact with case and cover

Abstract: An alternator assembly for an automotive vehicle including a rectifier device composed of a plurality of diodes supported on a negative-side cooling fin of semi-circular arc shape, a plurality of diodes supported on a positive-side cooling fin of semi-circular arc shape, and a terminal board supporting a plurality of terminals connected to the diodes. The rectifier device is assembled and held in a unitary structure by a plurality of metal members, and arranged in a space defined by an end frame and a rear cover of the alternator assembly in such a manner that the metal members are in contact at one end thereof with the rear cover and at the other end thereof with the end frame.

Multiterminal HVDC Transmission Systems Incorporating Diode Rectifier Stations

Abstract: A preferred mode of operating a parallel connected HVDC transmission system would be with at least one of the major rectifier stations in voltage control. Such a station could be realized using diode rectifier units.

Starting system for brushless motor

Abstract: A first static commutator including a first controllable thyristor rectifier and a first thyristor inverter and a second static commutator including a second controllable thyristor rectifier and a second thyristor inverter are provided. First three-phase AC voltage is supplied to the first controllable rectifier, and second three-phase AC voltage 30 degrees out of phase with said first three-phase AC voltage is supplied to the second controllable rectifier. A brushless motor includes first star-connected three-phase windings receiving the output of the first inverter and second star-connected three-phase windings and 30 degrees out of phase with said first three phase windings. During the starting period of the brushless motor the conduction of the first and second satic commutators is switched for every 30-degree rotation of the brushless motor.

Device for the field-oriented operation of a converter-fed asynchronous machine

Abstract: Disclosed is an apparatus for operating a converted-fed asynchronous electric motor which comprises a flux computer for determining the position of the flux vector from the input values for the stator voltage provided by said motor by solving all the electrical quantities of the Park equations describing said motor in a given position of the rotor axis, taking into account the parameter values corresponding to the rotor resistance and the stator resistance of said motor whereby signals corresponding to the position of the flux vector and belonging to a solution, can be tapped from said flux computer; a converter control unit coupled to said flux computer and said convertor rectifier respectively, forming the control quantities for driving the converter rectifier from the determined position of the flux vector and from the nominal input values which fix the components of the stator current vector parallel and perpendicular to the flux vector.

Automatic fault protection system for power recovery control

Abstract: An adjustable speed pumping system includes a plurality of pumps respectively driven by variable speed A.C. motors each having a power recovery circuit. Each power recovery circuit includes a series connected rectifier bridge, an inductive reactor and an inverter coupled to the secondary winding of the motor which has an A.C. source connected to the primary winding. A fault clearing mechanism is included in each circuit and includes solid state switches in the bridge actuated by a current level sensor coupled to the inverter output. The power recovery circuit also includes current foldback circuitry and secondary gating circuitry coupled to thyristors in the inverter. The power recovery circuits can be connected in parallel with a single motor and the system includes circuitry for sensing the highest amplitude current in the parallel circuits and controlling all circuits with this current. Each pump has a valve associated with the outlet and circuitry associated therewith to operate the pump at a low forward speed upon receipt of a stop command until the valve is closed to prevent significant reverse flow through the pump.

Saturable Inductor Based Controlled Waveform Excitation Source for Exploding Thin Film Atomic Spectroscopy

Abstract: An adjustable waveform excitation source for exploding thin film atomic spectroscopy is described. Waveform control is achieved through a saturable inductor having control windings and placed in series with the underdamped discharge tank circuit. This results in a high-current pulse for efficient sample atomization followed by a low-current measurement interval. When this is combined with gated integration, ∼15-fold increases in analysis line/background intensity ratios are observed for V and Mn. With additional inductance added to the circuit, the current and duration of both the atomization pulse and measurement interval can be adjusted independently. Other features of the excitation source include a plasma shunt capacitor, which results in more reproducible dielectric breakdown of the plasma support gas, and a variety of high-current series switches for initiating the discharge. Triggered spark gap, gravity operated spark gap, silicon-controlled rectifier, and ignitron switches are compared with respect to resistance and switching time jitter. Examples of discharge current and voltage waveforms and preliminary analytical data are presented.

Starting circuit for single phase electric motors

Abstract: A time responsive switching circuit for use with a single phase alternating current motor comprises a Triac in series with a start winding of the motor and controlled so as to disconnect the start winding after a predetermined time delay. The Triac is controlled by a timing circuit comprising a full wave rectifier bridge energized from the alternating current source, an RC charging network connected across the d.c. terminals of the bridge, a CMOS switching device responsive to the condition of the charging circuit, and an SCR controlled by the CMOS switching device. The SCR is switched off by the CMOS switching device after the chosen delay so as to remove the control potential from the Triac and so switch off the latter.

Controlled regenerative d-c power supply

Abstract: A-C energy, from an a-c power system, is converted by a phase-controlled SCR rectifier bridge, which is followed by a series-connected filter choke and a shunt-connected filter capacitor, to d-c power for delivery via a d-c bus to a load, such as an inverter and an a-c induction motor driven by the inverter. When there is a decrease in load demand, for example when the motor speed is to be reduced, fast speed control is obtained by regenerating power back into the a-c power system from the load. Power flow through the d-c power supply is reversed by means of a switching network, interposed between the filter choke and capacitor, having a pair of reverse SCR's for cross-coupling the positive and negative lines of the d-c bus. When the reverse SCR's are fired into conduction, the connections between the filter capacitor and the bridge's output terminals are effectively reversed, thereby facilitating power flow from the load to the a-c power system.

Method and device for the optimum use of at least one variable and hard to master power source

Abstract: A method and an installation are described for the optimum use of at least one variable power source which is difficult to control. In known power systems with a power source which is difficult to control, it is normal to couple to it one or more synchronous A.C. generators which can be connected with a rectifier and an inverter to an autonomous A.C. network. In this arrangement, the A.C. network is connected to a second synchronous A.C. generator which is mechanically connected, such that it can be disconnected therefrom, to a controllable auxiliary machine, such as e.g. a diesel generating set. To keep the frequency of the network constant if too much power is offered or, above all, if the power offered drops, such an amount of power is supplied from the autonomous A.C. network (5) to an additional usable load (2) that the frequency of the network (5) remains constant. The excess power to be diverted can be used, for example, for the preparation of hot water or for the electrolysis of water, combined with the use of fuel cells, or for battery charging or for pumping water to increased heights.

Induction Watthour Meter Performance on Rectifier/Inverter Circuits

Abstract: Experimental measurements of domestic induction watthour meter errors on single and three-phase rectifier and inverter systems are presented. The effect of bridge configuration as well as firing and overlap angles are reported.

On-chip CMOS bridge circuit

Abstract: There is disclosed a bridge circuit which finds particularly advantageous use in medical prostheses which can be programmed externally and which can transmit telemetry signals. The entire circuit is implemented on a single CMOS integrated circuit. Depending upon the values of two control bits, the bridge circuit functions to derive a powering potential from an externally transmitted signal, with or without regulation. Externally transmitted programming signals are detectable, and telemetry signals can be transmitted from the chip as well. There is no active switching of bridge devices during power rectification mode, and instead they are biased on continuously. This allows the rectifier to operate at carrier frequencies as high as several megahertz. All of this is achieved by using conventional CMOS processing techniques, without requiring any extra diffusion steps.

High efficiency rectifier with multiple outputs

Abstract: A half-wave and a full-wave rectifier using transistors as rectifying elements have independently controlled multiple output voltages obtained from a single power supply. The transistor used as a rectifying element has its turn-on controlled thus allowing voltage control by phase control action.

Voltage transient suppressor circuit

Abstract: A circuit for use with telephony systems or the like for protecting these systems, which may be comprised of integrated circuits, from high transient voltages. The circuit includes a silicon controller rectifier (SCR) having the cathode and anode coupled between an input of the telephony system and earth potential. The gate of the SCR is coupled via a resistor to the cathode thereof and is also returned through a reversed-biased diode to a source of bias potential whereby negative voltage transients are shorted to earth potential such that the integrated circuits as well as the bias potential source are not damaged.

Flow rate measuring device

Abstract: PURPOSE:To obtain a flow rate measuring device having a small amount of consumption and multiplied reliability with a simple constitution, by performing a time division multiplexing process. CONSTITUTION:A switch 33 of an energizing circuit 31, a switch 51 of an electromagnetic flow rate converter 11, etc. are switched via a timer 23. Then the energizing coils 5A and 5B of electromagnetic flow rate detectors 1A and 1B are energized with time division by the DC power which is obtained by converting the AC power supplied from a commercial power supply 21 with a rectifier 25, a capacitor 27, etc. Then the frequency signals corresponding to the flow rates which are detected with time division by the detectors 1A and 1B are multiplied via the switch 51 and processed by an F/V converting circuit 55, a reversible counter 59, a pulse code converter 63 and an optical signal converter 67 to be transmitted via an optical fiber without receiving any effect of noises. The circuits and component parts can be shared with each other, and the number of transmission lines is not increased. As a result, the power consumption is reduced with multiplied reliability for a flow rate measuring device with a simple constitution.

Reverse Energy Transfer through an AC Line Synchronized Pulse Width Modulated Sinewave Inverter

Abstract: Pulse width modulated inverters are used in battery supplied systems as AC standby power sources to supply high quality sinewaves to critical loads. In all these systems, means must be provided for battery charging. The traditional method uses a separate rectifier to charge the battery. A pulse width modulated four-quadrant inverter can be made to pass power in either direction, functioning as a synchronous rectifier to provide complete control for all battery charging requirements. In its simplest form, the charging scheme can be modelled as two synchronous AC voltage sources separated by an inductor. Power transfer is effected when one voltage source differs in amplitude and phase from the other. This report describes the basic theory of line synchronized inverter operation and the realization of this theory using a pulse width modulated inverter operating as a closed-loop switching amplifier. The piece-wise linear time domain analysis of actual inverter waveforms to battery charging conditions are presented. This analysis details the instantaneous energy flow into the battery during a full cycle of utility sinewave. System trade-offs to realize a cost-effective product are identified and discussed. Waveforms, system performance, and applications are presented.

Phase unbalance protector

Abstract: There is disclosed apparatus for detecting phase unbalance in a 3-phase electric power system and initiating protective shutdown for motors or other loads in the system which includes a 3-phase rectifier, a peak voltage measuring circuit, a comparison circuit for comparing each phase maximum with a predetermined proportion of the peak voltage and generating a pulse whenever a phase maximum exceeds the predetermined proportion of the peak voltage, a missing-pulse detection circuit receiving the pulses, a fault circuit producing a fault signal in response to a signal from the missing-pulse circuit, a delay circuit responsive to the fault circuit and a visual indicator and relay for indicating a persistent phase unbalance fault and initiating protective action.

Device for triggering an alarm system in the event of insufficiency of the transmission level, for the receiver module of an optical-fiber transmission system

Abstract: An alarm-triggering device for the receiver of an optical-fiber transmission system including in series a filter which has a passband located externally with respect to the band of frequencies employed for optical-fiber transmission and the input of which is connected to an avalanche photodiode, an amplifier, a rectifier, a voltage comparator circuit, and alarm-triggering circuit.

Apparatus for operating discharge lamps

Abstract: A low frequency AC voltage is rectified through a full-wave rectifier to obtain a pulsating voltage, which is superimposed with an auxiliary voltage of a predetermined level provided from an auxiliary power source, and the resultant composite pulsating voltage is inverted at an inverter to a high frequency voltage. The high frequency voltage thus obtained from the inverter is used to operate a discharge lamp. Minimum value V min of the resultant voltage is set to be 1/3 to 4/5 of the maximum value V max of the resultant voltage.

Air current rectifier plate on an air spinning device

Abstract: An air current rectifier plate surrounds the foremost air jet nozzle in an air spinning device. The rectifier plate produces a non-turbulent flow of air toward the waste suction pipe and prevents debris from back-flowing into the air jet nozzle.

Operational rectifier and bias generator

Abstract: An improved current mode operational rectifier having loop transmissions through both feedback paths of an operational amplifier stage which limit at unity gain. An improved bias generator which can be used to bias the operational rectifier is also disclosed.

Switched mode power supply

Abstract: Semiconductor circuit for supplying power to electrical equipment includes a control circuit with a first terminal for reference voltage connected, via a voltage divider formed of series connected resistances, to the anode of a diode; a second terminal for zero-crossing identification connected via a resistance to the cathode of the diode; a third terminal serving as an actual value input directly connected to a divider point of the voltage divider; a fourth terminal delivering a sawtooth voltage connected via a resistance to a terminal of a transformer primary winding; a fifth terminal serving as a protective input connected via a resistance to the cathode of another diode and, via two other resistances, to the cathode of a third diode having an anode connected to an input of a rectifier circuit; a sixth terminal for a reference potential connected via a capacitor to the fourth terminal and via another capacitor to the anode of the first-mentioned diode; a seventh terminal and an eighth terminal for respectively determining a control pulse potential of and pulse-controlling a transistor both connected via a resistance to a capacitor leading to the base of the transistor; and a ninth terminal serving as a power-supply input connected both to the cathode of the other diode and, via a capacitor, to a respective terminal of two secondary windings of the transformer.

Tomograph for producing transverse layer images

Abstract: In the illustrative embodiment, an X-ray tube is attached to a rotary mounting, and the structural elements of the X-ray generator on the high voltage side are disposed on the rotary mounting in an oil-filled tank; for the transfer of energy, a rotating current coupling is provided between the rotary mounting and a stationary energy supply installation, e.g. a mains rectifier. The anode of the X-ray tube is connected to ground potential.

Analog or gate circuit

Abstract: The maximum instantaneous value of analog signals from multiple sources is detected by means of an analog OR gate circuit in which the analog signal from each input is connected to both a positive and a negative half wave rectifier circuit. The outputs of the positive half wave rectifier circuit are OR wired together and the outputs of the negative half wave rectifier circuits are OR wired together and the OR outputs of both are summed to provide an output signal that is the maximum peak instantaneous signal. Because the maximum instantaneous signal from any channel reverse biases the other rectifiers, other signals are neither added nor subtracted from the output.

Feedback-Controlled Cascade Rectifier Source for HV Testing of Contaminated DC Insulators

Abstract: This paper provides general guide-lines for the design of a feedback-controlled cascade rectifier source for testing heavily polluted insulators. The basic elements of the circuit are investigated with respect to both technical operating constraints and overall cost. The steady-state and transient analyses are based on analog modelling and digital simulation and have been verified on full-scale 50-kV and 100-kV sources.