Showing papers on "Rectifier published in 1982"

The insulated gate rectifier (IGR): A new power switching device

Abstract: A new power semiconductor device called the Insulated Gate Rectifier (IGR) is described in this paper. This device has the advantages of operating at high current densities while requiring low gate drive power. The devices exhibit relatively slow switching speeds due to bipolar operation. The results of two dimensional computer modelling of the device structure are compared with measurements taken on devices fabricated with 600 volt forward and reverse blocking capability.

Rectifier control system for a DC power plant system

Abstract: A DC power plant system has the operation of its individual rectifiers controlled by a stored program control system for the purpose of optimizing power efficiency. Load power requirements are compared with rated capacities of operating rectifiers of the system and individual rectifiers are turned on or off so that the plant efficiency is always maximized. Rectifiers are selected for turn on and off in the basis of their rated power capacity and their accumulated operating times.

Controller for alternating current elevator

Abstract: An apparatus for controlling an AC powered elevator by rectifying a commercial AC power source into a direct current through a rectifier, converting the direct current into a variable frequency AC power through a main inverter, driving the AC motor by the thus converted AC power to operate the cage of the elevator, and sending the regenerated electric power back to the commercial AC power source via a regeneration inverter connected to the DC side of the main inverter when regeneration braking is applied to the electric motor. If the main inverter becomes defective, the main inverter is separated from the electric motor, the AC side of the regeneration inverter is connected to the motor, and the motor is operated by relying upon the regeneration inverter.

Electronic delay blasting circuit

Abstract: An electronic delay blasting cap (10) receives an input signal over leg wires (12, 14). The input signal is passed through a rectifier (16) to produce a D.C. signal on output lines (26, 28). The D.C. signal charges a storage capacitor (32). When the input signal is removed or the wires (12, 14) are opened or shorted, the charge storage capacitor (32) discharges through a resistor (36) to produce a voltage which charges a timing capacitor (38). When the voltage on capacitor (38) reaches the threshold voltage of a zener diode (48) the diode is rendered conductive which in turn activates an SCR (46). A resistive ignition element (44) is connected in series with the SCR (46) and the charge storage capacitor (32) and is ignited when the SCR (46) is turned on. The charge stored in capacitor (32) causes ignition of the ignition element (44).

Circuit arrangement for operating high-pressure gas discharge lamps

Abstract: A circuit for operating high-pressure gas discharge lamps comprises a full-wave rectifier (2) which is connected to an alternating voltage supply source and supplies an output direct voltage to a combinatorial circuit part comprising a switching transistor (3), a choke coil (4), a fly-wheel diode (5) and a storage capacitor (6), from which the lamp is energized. A further combinatorial circuit part (7, 8, 10, 11) comprises at least one electronic circuit element (7) coupled between the storage capacitor (6) and the lamp (9) and is controlled by a control device (12). The control device compares an instantaneous lamp current of higher frequency with a nominal-value signal composed of a sinusoidal voltage component having double the supply frequency and a d.c. voltage component having a value of at least the maximum amplitude of the sinusoidal voltage.

Control Design of an Active and Reactive Power HVDC Modulation System with Kalman Filtering

Abstract: This paper discusses results of an EPRI contract on control design for an ac/dc transmission system to increase power transfers limited by dynamic stability. The control is acbieved by modulating the rectifier dc current or power and the inverter dc voltage. Coordinated active and reactive power modulation is accomplished by Linear Quadratic (LQ) control design. Improved performance is realized by utilizing reactive power coupling between dc and ac networks to modulate dc and ac active power. For the demonstration system, power modulation with coordinated voltage modulation is shown to be about ten times more effective than power modulation alone. Control interactions between electromechanical modes of oscillation are eliminated by Kalman filtering. Filtering permits excellent control performance with a minimum of system measurements. Modern control technology is applied within realistic system constraints, such as measurements.

Pulse power supply for generating extremely short pulse high voltages

Abstract: A pulse power supply for generating extremely short pulse high voltages comprizing an ac charging high voltage, rectifier, pulse forming unit as a capacitive energy storage element, and an externally-controlled high speed synchronous switching unit, such as a mechanical synchronous spark switch of rotating type. The capacitive energy storage element, i.e. condenser is charged up by the ac charging high voltage source from zero voltage to its peak voltage through the rectifier without the use of current limiting resistance during its half cycle or desired polarity, i.e. negative one. Then, this charged potential of the capacitive element is kept, with the blocking action of the rectifier, until a desired instant of the next half cycle when the said switching unit is triggered from outside, e.g. by rotation of the rotor disc carrying the spark electrode elements, and the very short pulse high voltages are produced at this instant at the output of this pulse power supply. This charging scheme by an ac charging voltage altering from zero to its peak reduces greatly the power loss in the charging process of the capacitive element. The switching of the charged capacitive element to the load in the next half cycle when the rectifier is blocking avoid the short-circuit current to flow from the arc charging voltage source to the load, making the production of the pulse voltage stable and use of a large protective resistance unecessary.

Regenerative rectifier circuit

Abstract: A three-phase regenerative rectifier provides power flow from ac to dc using a three-phase rectifier bridge. The reversal of the input ac voltage at the input frequency commutates current in the rectifier devices. A power transistor or field-effect transistor is coupled in inverse parallel with each rectifier device to provide a path for current from the dc output of the rectifier back to the ac supply during regeneration. The rectifier devices can be phase controlled thyristors or diodes. Control means sense the three-phase voltage and switch the transistors in phase with the ac supply. Commutation of the transistors is provided by their self-contained turn-off capabilities.

On-chip bias generator

Abstract: An improved on-chip bias generator for producing a negative bias for the substrate of a VLSI FET chip for reducing the body effect and for increasing circuit speed. The improvement comprises active FETs to rectify a ring oscillator square wave output, thereby reducing the voltage losses in the rectifier and increasing the amount of voltage delivered to the substrate.

Switched mode power supply

Abstract: Switched mode power supplies have been disclosed for powering discharge lamps and other loads. In one example the line current is shaped, in response to a signal representing the load, or optionally the input, current to provide a suitably high power factor. The circuit, however, includes a switch breaking the input path which is found to be disadvantageous. The in­ vention provides a switching means (CT1) connected across the circuit to control the current without breaking the current path. A current sensing resistor (R1) in the input path senses the current and a potentiometer (6) senses the potential from the rectifier (1). These are compared in a comparator with hys­ teresis (7) the output of which controls the switching means (VT1). An FET (FET1) connected across part of potentiometer (6) varies the attenuation ratio thereof to maintain the output voltage constant.

Split windings motor vehicle alternator

Abstract: The alternator comprises an induction winding sub-divided into two half-windings (1, 2) each connected to the input terminals of a respective double half-wave rectifier circuit (3, 4). It further includes thyristors (14) each of which connects a terminal (A, B, C) of one half winding (1) to a non-homologous terminal (C',A',B') of the other half-winding (2) such that, when the thyristors (14) are triggered, the electromotive forces generated in the two said half-windings (1, 2) are added in phase with each other. When the speed of rotation of the engine of the motor vehicle is less than a predetermined value, the said thyristors (14) are triggered and hence the two half-windings (1, 2) are connected in series with each other. If the speed of rotation of the engine surpasses this predetermined value, the thyristors (14) are not triggered, and the two half-windings (1, 2) are connected in parallel with each other.

Protection system for immunizing an inverter system against a-c line voltage disturbances

Abstract: PROTECTION SYSTEM FOR IMMUNIZING AN INVERTER SYSTEM AGAINST A-C LINE VOLTAGE DISTURBANCES Abstract: When a-c power line voltage is rectified by a phase-controlled SCR rectifier bridge to develop an adjustable d-c bus voltage which is then con-verted by an inverter back to a-c for driving a load, such as a motor, line voltage disturbances, resulting from momentary power outages or major power reductions, will have a deleterious effect on the operation of the inverter system. Such disturbances will cause improper firing of the SCR's and the d-c bus voltage may increase con-siderably, disrupting the normal operation of the inverter system and possibly destroying the switching devices in the inverter. Immunization against the effects of the line voltage disturbances is obtained by shutting down or disabling (37,65-92) the phase-controlled SCR SCR rectifier bridge (10) anytime such a disturbance occurs. In this way, while the output voltage of the rectifier bridge is effectively interrupted during the ocrurrence of each. line voltage disturbance, the inverter (26) will continue to operate in near normal manner in response to the d-c voltage provided by the filter capacitor (19). At the conclusion of each dis-turbance, the operation of the rectifier bridge (10) will be slowly restored to normal to avoid overshoot of the d-c bus voltage.

Protected low-pressure discharge lamp operating circuit

Abstract: A fluorescent lamp control circuit which provides power at high frequency,or example in the order of 35 kHz, includes a push-pull oscillator circuit having two transistors (T1, T2), an inductance element (L1, L1'), and a capacitor (C1, C1') to supply the lamps (3, 3'). To prevent dangerous high voltages upon removal of the lamp load, connected to the oscillatory circuit and to the series resonance circuit, upon removal of failure of a lamp, a protective circuit is provided formed by a thyristor (TH) connected to short-circuit at least one of the transistors (T1) of the oscillatory circuit. Control energy is derived directly from the high-voltage supply by a rectifier (D1, D1') connected to the inductance (L1, L1') of the series resonance circuit, so that sufficient and reliable switching energy for the protective thyristor (TH) is always available, the firing criterion therefor being determined by the breakdown voltage of a breakdown element such as a diac (22) connected to a voltage divider (20, 21) and receiving its control voltage also from the high-voltage connection of the series resonance circuit (4) including the inductance, which also feeds the power supply capacitor (C3) for the thyristor (TH).

Single phase regeneration with a polyphase rectification power circuit

Abstract: A polyphase rectifier power circuit with single phase regenerative capability provides motoring power from a polyphase supply and returns single phase regenerative power to the supply. One embodiment uses pulse width modulation of the regenerative rectifier to limit line-to-line current flow through the regenerative rectifier during regeneration while another embodiment uses 180° conduction in the regenerative rectifier with the substitution of two thyristors for two diodes in the rectifier.

Piezoelectric ultor voltage generator for a television receiver

Abstract: An ultor voltage generator for a television receiver includes a piezoelectric transformer arrangement constituting a plurality of piezoelectric transformer elements, each having input, output and common electrodes. The voltage gain characteristic of each element has a relatively narrow frequency bandwidth about its natural frequency of mechanical vibration. The plurality of piezoelectric transformer elements are electrically connected in parallel. The output electrodes are connected to a supply terminal of the arrangement, and the input electrodes and common electrodes are connected to input and common terminals, respectively, of the arrangement. A source of alternating voltage is coupled between the input and common terminals to generate a higher amplitude alternating output voltage between the supply and common terminals. The alternating output voltage is applied to a doubler rectifier to generate a DC ultor voltage for the television receiver picture tube. The natural frequencies of the plurality of piezoelectric transformer elements differ from one another substantially in order to produce a resultant voltage gain characteristic of the entire arrangement that is of significantly broader frequency bandwidth than that of any one of the constituent elements.

Rectifier switch for electric lawn mowers

Abstract: A switch is disclosed which includes both a switching assembly and a bridge rectifier, the switch assembly including contacts for connecting a DC motor such as the motor of an electric lawn mower, to AC supply lines or for short-circuiting the motor to rapidly stop rotation of the motor. Diodes of the bridge rectifier have terminals which are directly secured to portions of metal members which also carry contacts of the switch and/or serve as terminals for connection to the motor or the supply lines.

Rectifier assembly with heat sink

Abstract: Two U-shaped sheet metal members having legs through which the cooling air passes have bases onto which at least two of the load current carrying diodes are fastened, the connection between the diodes and the sheet metal members forming the heat sink being a highly heat conductive connection.

Current limiter and VAR generator utilizing a superconducting coil

Abstract: A current control device which may act as a current limiter and/or a VAR generator through the use of a superconducting inductor is taught. In one of the embodiments of the present invention, a full wave bridge rectifier network is serially inserted in one leg of a high voltage transmission system. The output of the full wave bridge network has connected between it a superconducting coil in series with a bias supply. The biasing supply circulates current in the inductor. Should the line current exceed the value of the current circulating in the inductor, the inductor impedes the increase of current giving sufficient time for current interruption devices, should they be utilized, to operate. Additionally, the biasing supply may act as a VAR generator by controlling the current in the superconductor or in the power supply feeding it.

Power supply system

Abstract: A power factor improving system for a power supply system, comprising an AC power supply, a rectifier circuit connected to the AC power supply, a smoothing circuit for smoothing the output current of the rectifier circuit and supplying DC power to the load, an inductance element inserted in series between the power supply and the rectifier circuit, switching means including a switching element and a rectifier element inserted between the AC input terminal of the rectifier circuit and one of the DC output lines thereof, and a control circuit for subjecting the switching element of the switching means to on-off control at a frequency higher than the frequency of the AC power supply.

Automatic voltage regulation system for ac generator

Abstract: An output voltage of an AC generator is produced through a full-wave rectifier and converted into a digital signal by an A/D converter This digital signal is compared with a reference signal, and in accordance with the difference therebetween, the firing angle of a thyristor is controlled to regulate the field current Synchronous point detectors detect a synchronous point of the output voltage of the AC generator A microprocessor computes a firing angle of the thyristor in accordance with the difference between the digital signal and the reference signal and produces a signal representing the computed firing angle upon detection of the synchronous point The thyristor is fired at the firing angle computed by the microprocessor

Amplifier power supply controlled by audio signal

Abstract: A power control circuit (22) for selectively supplying power from a constantly available power source (20) to an amplified speaker (12) by sensing the existence of an audio signal in a differential stage by determining the differential potential signal between leads (16, 18) to produce a ground reference signal which is amplified by a transistor (28) and thereafter rectified (52) to provide a direct current signal which operates a relay driver transistor (42) which, in turn, operates a relay switch (46) to supply power to the speaker amplifier (14). The discontinuance of power to the speaker amplifier is delayed for a period of time after the discontinuance of the audio signal to the differential stage (24) by placing a capacitor (58) between the rectifier and the relay driver transistor (42) to power the relay driver transistor for a period of time after the audio signal is no longer being provided.

Standby power system

Abstract: A standby AC electrical power system connected between a load device and the AC line voltage comprises a voltage responsive control circuit connected between the AC line voltage source and a DC to AC inverter circuit. The control circuit generates a continuously pulsating DC control voltage which has an envelope which responds to and follows but at a different rate the increase and decrease in the envelope of the output of a full wave rectifier fed by the AC line voltage. The control voltage remains above a given triggering level when the average value of the rectified output for the current half cycle involved stays above a given monitored level indicating that the average value of the current half cycle of the AC line voltage is above a given low level and drops to the triggering level when the average value of the current half cycle of the AC line voltage drops to the given low level. The circuit which generates this control voltage comprises a multi-branched capacitor charge and discharge circuit having a first relatively long time constant producing branch which provides a relatively slowly increasing envelope in response to the rise in the envelope of the rectified output of a relatively short time constant producing branch which provides a relatively rapidly decreasing envelope in response to the drop in the envelope of the rectified output. A trigger circuit responds to the dropping of the envelope of the control voltage to the triggering level by connecting a DC battery to the DC to AC inverter circuit which then supplies an AC voltage to the load device.

Electronic ballast for a fluorescent or gas-discharge tube

Abstract: In an electronic ballast for a fluorescent or gas-discharge tube having a rectifier and an active harmonic filter, preferably a step-up converter, and a converter connected downstream therefrom for generating a high-frequency oscillation, the harmonic filter and the converter being pulsed, a common control circuit (5) is provided for the active harmonic filter (3) and the converter (4), which control circuit (5) is acted on by a clock generator (7) as a result of which an apparatus with a small structure and a minimum number of components is created.

Method and device for locating short circuits in circuit boards, wirings, lines, cables or the like

Abstract: An alternating voltage, the frequency of which is suitably between 5 kHz and 20 kHz for achieving a high efficiency, is applied to the conductors of a, for example, single- or multi-layer circuit board, which conductors are connected to one another by a short circuit. To keep down the influence of disturbing parallel capacitances, the audio-frequency alternating voltage is preferably superimposed on a direct voltage. To determine the course of the circuit closed by the short circuit, the magnetic field occurring along the conductors through which the current flows is detected by means of a movable electromagnetic probe (40). The signal occurring at the output of the probe, the amplitude of which changes as a function of the distance from the conductors through which the current flows, is rectified in a rectifier (42) and then used for generating a control voltage which drives a voltage-controlled oscillator (46). The output frequency of the voltage-controlled oscillator (46), which changes as a function of the amplitude of the output signal of the probe (40), is supplied to an electroacoustic transducer (50). The maximum output frequency of the voltage-controlled oscillator (46) is preferably 1.5 kHz. Since the human ear responds very finely to frequencies within the range up to 1.5 kHz, the conductor through which the current flows can be very easily and correctly traced, and the short circuit located, by moving the probe (40).

Device for prolonging the life of an incandescent lamp

Abstract: A device for prolonging the life of an incandescent lamp includes a rectifier unit adapted for attachment to a lamp base and subsequent insertion into an appropriate lamp socket along with the lamp. The rectifier unit employs a leadless diode chip which is positioned off center within the socket so that the forces applied to the rectifier unit as the lamp is being screwed into the socket will not be applied directly to the diode chip. The rectifier unit also employs a pair of recessed electrical contacts attached to the diode chip and designed to minimize the distance that the unit raises the lamp in the socket and to conduct away the heat generated by the diode chip.

Control system for controlling an scr network to regulate three-phase a-c power flow

Abstract: The power delivered from a three-phase A-C power source and through a network of SCR's (connected, for example, to form a full wave rectifier bridge or to provide an A-C switch) to a load circuit is adjusted by controlling the conduction angles of the SCR's. The control is achieved by developing, from only one of the three alternating phase voltages provided by the A-C power supply, a reference square wave signal of the same frequency and whose amplitude excursions are precisely synchronized or keyed to the zero voltage crossings of the selected phase voltage, even though that phase voltage may include undesired harmonics, noise, transients or other distortion components. Since the influence of the undesired signal components has now been eliminated and since the reference square wave signal also has a fixed phase relationship with the other two phase voltages, logic circuitry may be controlled by the reference square wave signal, and by a d-c control voltage representing a desired power flow to the load circuit, to produce gating signals for triggering the SCR's into conduction at the angles required to translate the desired power to the load circuit. With this arrangement, control of all three phases is made immune to undesired signal components in any of the phase voltages.

Switching power supply

Abstract: PURPOSE:To stabilize a secondary coil output voltage by correcting a voltage corresponding to the voltage of a secondary coil generated in a tertiary coil through a voltage corresponding to the peak value of a current flowing through a primary coil and by performing switching control on the basis of the corrected voltage corresponding to the voltage across the secondary coil. CONSTITUTION:AC power supply 1 output is full wave-rectified by a full-wave rectifier circuit 3. This current is switched by FET 8 to flow to the primary coil L1 of a transformer 4. Also, the current flows to a secondary coil L2 and voltage corresponding to charge electrifying a capacitor C2 is applied to a load 9. In a correction circuit 6, a voltage corresponding to the voltage (voltage across the secondary coil L2) applied to the load 9 generated in a tertiary coil L3 is corrected by a voltage corresponding to the peak value of the current flowing through the primary coil L1 supplied from a detection circuit 5. In PWM control circuit 7, drive pulse is applied to the gate of the FET8 on the basis of the corrected voltage corresponding to the voltage in the secondary coil L2.

Portable DC device for verifying absence of voltage in high-tension AC conductors

Abstract: A device for determining whether electrical equipment carries an alternating current that could endanger maintenance personnel or others in contact with the equipment comprises a conductive probe, a rectifier, a threshold detector and an alarm. The conductive probe makes electrical contact with the equipment, and the rectifier rectifies a fraction of any alternating current carried by the probe as a result of such contact to produce a unipolar signal. The threshold detector responds to the unipolar signal and generates an output signal when the voltage of the unipolar signal exceeds a predetermined threshold. The alarm gives a warning response to said output signal.

Rapid-start, low-pressure discharge lamp operating circuit

Abstract: To insure starting of an oscillatory circuit for fluorescent lamp operationscillating, for example, at about 35 kHz, two transistors are serially connected across the output of a rectifier adapted for connection to an a-c network, and the oscillatory circuit is additionally coupled to one of the a-c terminals of the rectifier, to apply to one of the transistors a triggering voltage which recurs with each undulation of the a-c network. The serially connected transistors each have an emitter resistor, which may be a PTC resistor, to balance currents through the transistors and eliminate unbalancing effects of manufacturing tolerances in the transistors. The PTC resistors additionally have current deviation regulating function. For multiple-lamp operation, oscillation control is derived from auxiliary windings on the ballast resistors and applied to the bases of the respective transistors (T1, T2) through an inductance network which insures spaced commutation or switching of the transistors and prevents overlap of conduction phases thereof.