Showing papers on "Rectifier published in 1969"

Stability Analysis of a Rectifier-Inverter Induction Motor Drive

Abstract: A stability study of a rectifier-inverter induction motor drive system is performed by neglecting the harmonic content of the stator voltages and applying Nyquist stability criterion to the small- displacement equations obtained by linearization about an operating point. This investigation reveals that system instability can occur over a wide speed range if the system parameters are improperly selected. It appears that the method of analysis presented in this paper is sufficient to predict stability of practical rectifier-inverter induction motor drive systems. Also, with slight modifications, this method of analysis can be applied to rectifier-inverter systems which supply reluctance-synchronous machines or synchronous machines.

Brushless oil-colled generator

Abstract: A brushless DC oil cooled generator utilizing delta windings displaced by 30 electrical degrees, feeding through a full wave rectifier system to a common bus. Also improved means are provided for cooling and mounting the rectifiers.

Automatically resetting transient protection device

Abstract: Apparatus for protecting electrical circuitry from voltage transients in a power supply or the like connected to the circuitry. A plurality of diodes and a silicon controlled rectifier are connected in series across the output of the power supply. The silicon controlled rectifier is triggered by a predetermined transient voltage level, and the output voltage of the power supply is clamped at the sum of the forward voltage drops of the diodes and controlled rectifier, the sum being set above the normal output voltage level of the power supply. The silicon controlled rectifier then commutates as soon as the transient ceases and the voltage level drops to normal. Various configurations are provided for DC or AC systems, as well as for remote sensing, and additional compensating circuits are employed for various applications.

Analysis and Simplified Representations of Rectifier - Inverter Reluctance-Synchronous Motor Drives

Abstract: Methods of analyzing six-step and pulse-width- modulated (PWM) types of rectifier-inverter reluctance-synchronous motor drive systems are set forth. In this development the harmonic components due to the switching of the rectifier are neglected, and the operation of the inverter is expressed in a reference frame rotating in synchronism with the fundamental frequency of the inverter output voltages. In the case of the PWM inverter, the Fourier series expansion of a pulse train is used to express the operation of this type of inverter in the synchronously rotating reference frame. Simplified representations are obtained by neglecting the harmonics due to the inverter switching. These simplified representations are verified by comparing the results obtained from a computer study using these representations to those obtained using a detailed simulation of the system. The analysis set forth and the simplified representations that are developed can be used to determine small-displacement system stability, as well as provide a simple and direct technique of predicting the dynamic and steadystate performance of these involved systems. Moreover, the equations established for the PWM inverter can also be used in conjunction with an induction motor drive.

Energizing Implantable Transmitters by Means of Coupled Inductance Coils

Abstract: In the study of energizing implantable oscillators by coupling of inductance coils, it is pointed out that the best stability is not necessarily obtained where the magnetic flux density takes its maximum. The conversion of the induced ac voltage to a useful dc voltage can be made in conventional rectifier circuits, but great improvement in operation and economy is offered by transistor rectifier circuits. Two types of transistor rectifiers?the common-base and the common-collector arrangements?are discussed in detail.

High d/d, fast turn-on darlington controlled semiconductor switch

Abstract: A high di/dt, fast turn-on Darlington controlled rectifier semithyristor semiconductor switch embodies a body of semiconductor material wherein two controlled rectifier switches are formed, each having a separate gate and a separate cathode but both sharing a common anode. The cathode current of one controlled rectifier switch is the gate current for the second controlled rectifier switch thereby enabling a small initial current to be amplified and turn-on a larger controlled rectifier switch whereby the overall effect is a fast turn-on gate controlled switch with a high di/dt rating.

Ac car dynamo

Abstract: An AC dynamo in which a rectifier, a voltage regulator and brush holders are disposed in stacked relationship, all these elements being secured to an end bracket of the dynamo by common securing means which provide electrical connection means between the elements as well as serve as electrical terminal means.

Infinite speed control switching device for use with electric motors in portable tools

Abstract: A trigger-operated power control switch for electric motors in portable tools, wherein control circuitry including a condenser, a fixed resistor, a silicon-controlled rectifier, a neon tube, and a potentiometer or variable resistance with which is combined switching means for isolating these parts from the source of power by opening the circuit in both powerline conductors in "off" position and for bypassing said control circuitry in full "on" position. The trigger operates the potentiometer and also controls the switching operations.

Analog computer simulation of a three-phase full-wave controlled rectifier bridge

Abstract: This paper establishes analog computer simulations of the widely used three-phase full-wave controlled rectifier bridge. It is shown that when the individual currents in the legs of the rectifier bridge are not developed directly in the simulation, it is possible to avoid the instability and drift problems which have plagued previous investigators. Furthermore, by proper attention to the periodic nature of the operation of the rectifier bridge, the number of computer components may be considerably reduced. In particular, only two electronic switches need be used if the operating range of the delay angle is small. The unique features of the modern high-speed repetitive-operation type of analog computer are utilized throughout the analysis. Computation time is typically reduced by a factor of 300 when compared with existing digital computer routines. The accuracy of the simulation is illustrated by comparing the computer output to recordings taken from an actual system. Good correlation is demonstrated for both transient and steady-state operation.

Circuit for the protection of monolithic silicon-controlled rectifiers from false triggering

Abstract: Power supply voltage transients are prevented from turning on a silicon-controlled rectifier by use of a dual-emitter current switch to short circuit a given PN junction within the siliconcontrolled rectifier for the duration of each transient.

Ignition circuit with automatic spark advance

Abstract: A solid state capacitor discharge ignition system for use in a single-cylinder engine having a magneto for an electrical energy source wherein the capacitor is discharged through a silicon controlled rectifier in response to trigger signals generated by a trigger assembly mounted on the rotor and stator of the magneto. The trigger assembly generates at least two discrete spaced pulses at running and cranking speeds, and the spacing between the two pulses corresponds to a desired shift in the engine timing between cranking and running speeds. The trigger assembly, the silicon controlled rectifier and the circuit connection therebetween are such that both pulses are applied to the controlled rectifier at all engine speeds; but the retarded ignition pulse is effective at cranking speeds and the advance pulse is effective at running speeds.

Current limiting system for motor control

Abstract: A system is disclosed for limiting the current to a motor operative with the controlled power supply including controlled rectifier devices for converting an AC input to a DC output wherein a firing circuit is provided which generates firing pulses for controlling the conductive period of the controlled rectifiers when a base voltage having a sawtooth voltage superimposed thereon exceeds a predetermined value. A current indicative of the magnitude of the actual current through the motor is sensed and is utilized to control the magnitude of the base voltage whenever the sensed current exceeds a preselected magnitude so that the current through the motor is limited to safe values. Whenever the sensed current exceeds the preselected value by a predetermined larger amount, a fast response circuit is utilized to remove quickly the overcurrent condition from the motor.

Thyristor with improved current and voltage handling characteristics

Abstract: A controlled rectifier is disclosed which is comprised of a main current carrying thyristor which surrounds an integrated gate signal amplifying thyristor. The main thyristor is peripherally beveled to increase the voltage blocking capabilities of the controlled rectifier. The surface of the base layer of the main thyristor is provided with an exposed surface lying at a lower level than the surface of the adjacent emitter layer of the main thyristor, and the exposed base layer surface is interdigitated with the adjacent emitter layer. A metallic contact ohmically connects an emitter layer of the amplifying thyristor to the exposed base layer surface of the main thyristor. The base layer of the main thyristor is also provided with exposed surface portions coplanar with the adjacent emitter layer surface at locations most remote from the fingers of the base layer surface. Additionally, a relatively high resistance current spreading path is provided associated with the emitter layer of the amplifying thyristor, and the amplifying thyristor emitter layer is provided with a minimum spacing from the control lead adjacent the spreading path.

Method of Multiple Reference Frames Applied to the Analysis of a Rectifier - Inverter Induction Motor Drive

Abstract: The method of multiple reference frames and the equations of transformation of the inverter are employed to establish a method of calculating the inverter current in a rectifier - inverter drive system. Since the method of multiple reference frames does not use phasors or complex impedances, the calculation of the inverter current is simple and direct. Also presented is a method of approximating the 6th harmonic variation in the capacitor voltage of the filter, connected between the rectifier and the inverter. This method permits a simplified means of rapidly obtaining a first- order approximation of the variation in the capacitor voltage. The analysis establishes a straightforward method of calculating variables in a rectifier - inverter drive system, which are difficult to determine by conventional methods of analysis.

Motor control circuit

Abstract: Alternating current rectified by a bridge rectifier is supplied through an SCR device to a motor armature; the bridge rectifier, SCR device, and armature being connected in a series loop circuit. A firing control circuit associated with the SCR device controls the angle at which the device fires during each half cycle of alternating current received from the bridge rectifier. A storage capacitor and a freewheeling diode are coupled in parallel with the armature to assist in filtering. A resistor connected in series with the armature produces a feedback voltage signal which is proportional to armature current, and a resistive circuit branch arranged in parallel with the armature provides a feedback voltage signal which is proportional to armature voltage. A signal responsive circuit combines the two voltage feedback signals into a composite control signal for controlling the firing control circuit previously referred to. The firing control circuit is connected between anode and cathode of the SCR device for receiving its operating energy when the SCR device is nonconductive.

Rectifier test method

Abstract: A method for measuring characteristics of semiconductor devices having a junction. This method includes the steps of heating a junction of a semiconductor device by supplying the device with a predetermined current for a predetermined time, supplying the device with a reverse bias voltage, and measuring the voltage across and current through the device at certain times during the test. Testing by this method yields indications as to the temperature the junction in the semiconductor device will reach during operation, the quality of the mechanical connections to the junction, the junction forward voltage characteristic slope, and the likelihood of the device undergoing thermal runaway.

Dark current compensation circuit

Abstract: A dark current compensation circuit for a television camera features a switch for controlling an X-ray tube located in front of the camera, a video amplifier is coupled to the camera and a peak rectifier circuit is in turn coupled to the amplifier output. A switch synchronized with the first switch connects the rectifier to a capacitor to establish a dark current bias voltage which is applied to the amplifier.

Apparatus for providing uninterrupted power to a load

Abstract: Apparatus for switching power sources to a load without interruption is disclosed. The apparatus includes a source of rectified and filtered AC, a regulator, and a load. The AC source feeds DC power of given voltage to two terminals. A sensing and power delivery circuit is connected to these same two terminals to provide power from a DC source when the power from the AC mains suffers a degradation. The sensing and power delivery circuit includes a saturable switching transistor which switches the battery across the above-mentioned two terminals when a sensing circuit detects a change in the rectified and filtered AC. The sensing circuit controls a controlled rectifier which closes a current path around the battery permitting the switching transistor to saturate thereby effectively placing the DC source across the load terminals. A battery charging arrangement is also shown.

Demagnetizing circuit arrangement with dc voltage means to reduce current through the demagnetizing coil to zero

Abstract: A demagnetizing circuit arrangement to be supplied by an AC voltage source and suitable for rapidly repeated demagnetization, including a demagnetizing coil in series with a full-wave rectifier circuit. For obtaining, after switching on the demagnetizing circuit arrangement, a demagnetizing current having an amplitude decreasing to the zero value without the current being interrupted by an additional switch the circuit arrangement according to the invention is provided with a DC voltage source formed, for example, as a rectifier circuit, the increasing maximum voltage of which causes the full-wave rectifier circuit to interrupt the demagnetizing current.

Circuit protection apparatus for disabling high voltage to a cathode-ray tube

Abstract: D R A W I N G THE CATHODE-RAY TUBE OF AN OSCILLOSCOPE CAN BE PROTECTED WHEN THE HORIZONTAL SWEEP GENERATOR THEREOF FAILS TO PRODUCE AN OUTPUT SIGNAL BY PROVIDING A CAPACITOR THAT IS PERIODICALLY DISCHARGED THROUGH A CONTROLLED RECTIFIER IN RESPONSE TO SIGNALS RECEIVED FROM THE HORIZONTAL SWEEP GENERATOR. IF THE HORIZONTAL SWEEP GENERATOR FAILS TO PRODUCE AN OUTPUT SIGNAL, THE CONTROLLED RECTIFIER IS NOT OPERATED AND THE CAPACITOR CHARGES TO A VOLTAGE SUFFICIENT TO ACTIVATE A SWITCH DEVICE. THE SWITCH DEVICE, IN TURN, DISABLES THE HIGH VOLTAGE POWER SUPPLY THAT OPERATES THE CATHODE-RAY TUBE.

Electrical chopper regulator circuits

Abstract: An electrical chopper regulator circuit comprises a main controllable rectifier device connected in a current path between input and output terminals and a commutating capacitor connected in a second current path. Second and third controllable rectifier devices control connection of the commutating capacitor with appropriate polarity to opposite sides of the main controllable rectifier device so as to interrupt current flow in the main controllable rectifier device. A charging circuit for controlling charging of the commutating capacitor includes a switching device and an inductance through which current flows to charge the commutating capacitor to the correct polarity for commutating the main controllable rectifier device before firing of that device.

Ignition system for internal combustion engines

Abstract: An ignition system of a capacitor discharging type for internal combustion engines having a DC-DC converter, a discharging capacitor, an ignition coil and a silicon-controlled rectifier In the system, a differentiation circuit, a waveform shaping circuit and a switching element are additionally provided so that the switching element interposed in the base-emitter circuit of an oscillation transistor in the DC-DC converter is actuated by the output pulse from the waveform shaping circuit to cease the operation of the DC-DC converter for a period of time corresponding to the duration of the pulse

Device for the production of a high direct voltage difference

Abstract: A transfer coil consisting of a loop provided with a sufficient electrical insulation is fed by an AC source and is inductively coupled with a plurality of cells. Each cell consists of a winding coupled with the loop and a rectifier circuit fed by the winding. The outputs of all rectifiers are in series aiding relation. In a first embodiment the loop is closed and inductively coupled to the source, making it possible to connect it to half the high voltage. In another embodiment, the loop ends are connected to a winding inductively coupled with the source and the loop is at the source DC potential.

Control systems for electric motors

Abstract: A motor drive circuit in which a direct current motor is fed with pulses of current by means of a controlled rectifier connected as a power switch between a power source and the motor. The conduction of the rectifier is controlled by a potential divider one element of which is a flux-responsive resistor adjacent a conductor of armature current. The divider is energized with a constant voltage thereby avoiding use of a freerunning pulse generator as a source of trigger pulses for the rectifier. A coil adjacent the resistor provides additional flux through the resistor for controlling the pulse rate of the motor.

Self-starting power converter

Abstract: A STARTING SYSTEM FOR A SYNCHRONOUSLY COMMUTATED POWER CONVERSION UNIT. DURING START-UP A BRIDGE RECTIFIER IS CONNECTED AND OPERATED AS AN AC REGULATOR TO PROVIDE A VARIABLE REDUCED VOLTAGE TO THE SYNCHRONOUS CONDENSER. AFTER START-UP THE BRIDGE RECRIFIER IS RECONNECTED AS A PHASE DELAY RECTIFIER.

Electrical power supply system for automotive vehicles and particularly polyphase bridge-type rectifier therefor

Abstract: To prevent transient overvoltages in automotive-type power supply systems using three-phase alternators and full wave rectifiers connected thereto, at least one of the rectifier pairs connected to an output winding of the alternator uses breakdowntype power rectifier diodes having a breakdown voltage at least 5 percent above the nominal voltage set by the voltage regulator of the system. Connection of breakdown diodes to further, or preferably all phases provides still better protection at greater expense, however.

Ignition device for internal combustion engine

Abstract: A low DC voltage boosted by an inverter and a rectifier charges a capacitor a charge on which is, in turn, discharged into an ignition coil under control of a thyristor Upon starting the engine, the DC voltage is applied to an intermediate terminal of a primary transformer winding in the inverter Diodes are connected in a circuit for gating the thyristor to prevent the circuit from partly short-circuiting the primary winding through the intermediate terminal