Showing papers on "Rectifier published in 1980"

Combined antenna-rectifier arrays for power distribution systems

Abstract: An electrical power distribution system wherein electromagnetic energy irradiates a large spatial area is configured to include an array of antenna-rectifier modules wherein the receive aperture of each module is established in accordance with the electromagnetic field intensity at the location of that particular module so as to provide the rectifier circuitry with a predetermined amount of electrical power. Each antenna-rectifier module includes an array of high impedance (e.g., antiresonant) dipoles that are spaced apart along a two-wire transmission line. The total number of dipoles employed is established to provide the desired receive aperture and the impedance of each dipole is established so that the total impedance of the array substantially matches that of the rectifier circuitry employed. The rectifier circuitry is enclosed in and electromagnetically shielded by a conductive housing that is removably interconnected with the array of antenna elements and first and second filtering circuits are included to respectively eliminate high frequency signal components that can be coupled to and radiated by the antenna structure and high frequency ripple within the DC output signal.

Application of RF Circuit Design Principles to Distributed Power Converters

Abstract: The application of RF circuit design principles to high-frequency power converters is described. Compared to conventional converter design, emphasis is placed on obtaining sinusoidal-type waveforms (instead of rectangular-type waveforms) to minimize device switching time requirements and alleviate transforming requirements. A 25-W 48-V to 5-V dc-to-dc converter design using a 5-MHz switching frequency is presented illustrating these principles, using a Class E power amplifier, an L section impedance transformer, and a shunt-mounted harmonically tuned rectifier circuit. Computer simulation results are presented that indicate the feasibility of the proposed design approach, specify required circuit parameters and indicate that line and load regulation can be achieved with narrow-band frequency control. Experimental results on a low power 5-W, 25-V to 5-V dc-to-dc converter breadboard using a 10-MHz switching frequency with the described circuit topology are presented. An efficiency of 68 percent was obtained and load regulation by frequency control demonstrated. Inductor Q requirements limit the conversion efficiency of the proposed converter, and will probably be the limiting factor in obtaining high efficiency with similar design approaches.

Operation control apparatus for AC motors

Abstract: An apparatus for controlling the operation of an AC motor wherein braking energy at the time of a reduction in motor speed is disposed of by regenerative braking. The apparatus includes a rectifier which is connected to the AC power source, a DC link which includes smoothing capacitors and a regenerative transistor bridge circuit, a variable voltage-variable frequency inverter. Further provided are a diode which is connected between the rectifier and the transistor bridge circuit and which is biased in the reverse direction at the time of regenerative braking, and a firing control circuit for detecting the reverse bias voltage of the diode to control the firing of each transistor in the transistor bridge circuit, the braking energy being fed back to the AC power source when the AC motor undergoes a reduction in speed. The apparatus, which provides stable regenerative operation, can be constructed simply and inexpensively, and reduced in size.

Battery charging systems for road vehicles

Abstract: A road vehicle battery charging system includes an alternator, and a rectifier connecting the alternator across a battery. A further rectifier provides an additional d.c. output for energising the field winding of the alternator and this additional output is connected to the appropriate battery terminal via an ignition switch. A voltage sensing circuit operates to illuminate a warning lamp should the voltage on the line exceed a predetermined level.

Rectifier Harmonics in Power Systems

Abstract: The effect of rectifier harmonic currents on power systems is described. Rectifiers and inverters require nonsinusoidal waves of current. These current waves are made up of a number of sine waves which are harmonics of the fundamental wave. These harmonic currents can excite resonant circuits causing them to ``ring'' and produce large oscillating currents. Criteria as to possible problem areas are discussed and illustrated with case studies. Examples of application of filters to ``trap'' these harmonic currents are included.

Apparatus for reproducing disc record

Abstract: Apparatus for maintaining a constant linear velocity for a PCM disc record which includes a detector for optically detecting the PCM signal on the record and supplies the output to a differentiating circuit and a rectifier circuit with the output of the rectifier circuit supplied to a peak detector circuit which supplies its output to a level comparator that also receives a reference level from a reference source. A first phase comparator also receives the output of the rectifier circuit and controls a voltage controlled oscillator through a low pass filter and the output of the voltage controlled oscillator is supplied to the phase comparator. A divider receives the output of the voltage controlled oscillator and supplies a first input to a phase comparator which also receives an input from a reference frequency generator. The outputs of the level comparator and the phase comparator are supplied to the motor drive circuit which controls the drive motor for the disc record.

Generation control apparatus for vehicle generators

Abstract: A generation control apparatus for a vehicle generator includes an energization circuit consisting of an energization path forming resistance element and switching means and provided between the output terminal of a rectifier circuit of the generator and the ground, and an oscillator circuit responsive to the voltage at the output terminal of the rectifier circuit to always oscillate and control the energization circuit, whereby an energization path is intermittently provided in response to the output signal of the oscillator circuit. If a generation fault condition is detected, current is caused to flow from a battery through a key switch, indicator means and the energization path forming resistor intermittently and the driver of the vehicle is alerted to the generation fault of the generator or a break in an excitation circuit by a flashing of the indicator means.

Series parallel transition for power supply

Abstract: A multi-winding a-c electric power supply is connected to a d-c load circuit via a power rectifier assembly comprising at least two legs connected in parallel across the load circuit. Each leg has at least four serially interconnected unilaterally conducting devices. A first one of the power supply windings is connected between the two rectifier legs at points between first and second devices thereof, and a duplicate winding (voltages of both windings are in-phase and of equal amplitude) is connected between the legs at points between third and fourth devices thereof, whereby the windings are effectively connected in parallel. The respective junctures of the second and third devices in all of the rectifier legs are interconnected by switching means which, upon switching to a closed circuit state, short circuits these junctures and thereby changes the connection of the windings from parallel to series.

Method and apparatus for remotely controlling an electrical appliance

Abstract: A transmitter (12) has an output (13) adapted to be connected across an alternating current power line (AC1, AC2) at a point remote from an appliance (24) to be controlled. The transmitter generates one pulse per cycle of the alternating current. The pulse phase has a predetermined value with respect to the alternating current. A receiver (21) is adapted to be connected across the power line to couple the line to the appliance. When the receiver detects transmitter generated pulses during phase windows occurring each alternating current cycle, power is applied from the line to the appliance for the remainder of such alternating current cycle. The transmitter has an adjustment (14) that permits the phase of the transmitter generated pulses to be modulated and the receiver has an adjustment (26) that permits the position of the phase windows relative to the alternating current to be changed. The transmitter generated pulses and the phase windows occur only on every other half cycle of the alternating current. The transmitter includes a controlled rectifier which is fired on every other half cycle of the alternating current to generate the transmitter pulses; after firing, the controlled rectifier remains in a conducting state during the remainder of the alternating current half cycle.

Load state control for an asynchronous machine fed by a converter

Abstract: A control unit for regulating an asynchronous motor supplied with power from a three phase network by a line-controlled power converter which is DC coupled to a self-commutated inverter has a function generator and a current regulator which controls the stator current of the motor by the controlling rectifier valves in the inverter. Control of the stator current is a function of a predeterminable value of flux fed into the function generator. In a parallel control system, an actual-value computer and a load state control regulate the stator frequency by generating a signal for controlling the self-commutating converter as a function of the actual values of the stator current, the stator voltage, and a value calculated from the function generator input variable. The computer forms signals corresponding to the amplitude of the flux vector, and to a stator current component perpendicular to the flux vector. A variable derived from the predeterminable variable is applied to the load state control as a reference value. Fall-out-proof, low oscillation, speed control is effected from low angles to nearly 90°.

Rectifier-converter power supply with multi-channel flyback inverter

Abstract: An AC to DC power supply having a multi-channel, flyback inverter output section regulated via a fixed frequency, pulse width modulation controller. The controller indirectly regulates each channel by regulating an auxiliary channel, whereby the duty cycle of a switching transistor in the flyback inverter section is varied to maintain a constant DC voltage on the auxiliary channel and correspondingly on each output channel.

Blown fuse sensor

Abstract: Each arm forming a three-phase full wave rectifier bridge includes a semiconductor diode, a current transformer and a fuse. The current transformer is connected to a pulse extinction indicator circuit through a pulse transformer. When no current flows through the arm for a predetermined time or more, the pulse extinction detection circuit produces a DC signal indicating the blowing of the fuse. The rectifier bridge, the current transformers, the fuses and the pulse extinction detection circuit are all disposed on the rotor of a brushless synchronous machine.

Aircraft providing variable and constant electric power

Abstract: The invention is a two-level power system for electrically powered aircraft sub-systems. An aircraft engine (2) drives a three phase generator (30) at a variable speed. The output of generator (30) is primary variable-voltage/variable-frequency (VV-VF) power which is utilized by various aircraft subsystems. A portion of the primary VV-VF power is converted to constant voltage-constant frequency (CV-CF) power by an inverter (31) which includes front end rectification. The CV-CF power is then available to selected aircraft subsystems while portions of the CV-CF power are converted by rectifier (32) and transformer-rectifier (33) into 270 vdc and 28 vdc power, respectively, which power is also then available to aircraft sub-systems.

Test system for cathodic protection circuit of an underground pipeline

Abstract: An apparatus for testing the pipe-to-soil potential of a buried pipeline having a plurality of rectifiers electrically connected to it in spaced-apart intervals for applying an electrical potential to the pipe includes a plurality of interrupter units electrically connected to the rectifiers for turning them on and off at intervals. A clock reference unit is electrically connectable to each of the interrupters for synchronizing them for turning all of the rectifiers on and off in unison. A portable sensing device produces signals indicative of the pipe-to-soil potential of the pipe and directs these signals to a demultiplexer unit which is also synchronized with the clock reference unit for separating the signals corresponding to the ON and OFF potentials which are then separately recorded. The method of the invention thus includes alternately turning each rectifier on and off, synchronizing the turning on and off of all of the rectifiers, producing signals indicative of the pipe-to-soil potential of the pipe at various positions therealong and separating the signals indicative of the ON and OFF potentials in synchronization with the rectifiers so that the ON and OFF potentials may be separately recorded.

Smooth series parallel transition for dual winding traction alternator

Abstract: An engine-driven dual winding separately excited alternator supplies electric power to a parallel array of d-c traction motors via a power rectifier assembly comprising three legs of serially interconnected diodes. The alternator has a first set of 3-phase windings respectively connected to the three rectifier legs at points between first and second diodes thereof and another set of duplicate windings respectively connected to the corresponding legs at points between third and fourth diodes thereof. First and second switching means are used to interconnect the respective junctures of the second and third diodes of all three rectifier legs, and in response to transition command signals these switching means are selectively closed (or opened) in sequence to change the connection of the alternator windings from parallel to series (or vice versa). Stabilizing means associated with the excitation system of the alternator is temporarily disabled during the transition interval.

Regulator for a generator energized battery

Abstract: An energy regulating system (21) includes a battery (25) connected to a single phase generator winding (23) through a connecting circuit (24) providing a full wave bridge rectifier (26) having a pair of controlled rectifiers (69, 71) which are selectively gated into connection in response to the sensed phase angle of the energy in the winding (23). A control (54) operates in response to a charge sensor (31) which senses the charge on the battery (25) and a phase sensor (79) which senses the energy phase at the winding (23) to operate a switch (44) to modify the operation of the bridge circuit (26) to interrupt the energy flow to the battery (25). An excessive energy sensor (80) responds to excessive sensed energy at the connecting circuit (24) to turn on a pair of controlled rectifiers (53, 70) to deactivate the bridge circuit (26) to prevent damage to the connecting circuit (24).

Signal-powered receiver

Abstract: A self-powered receiver including a series resonant circuit tuned to the carrier frequency of a modulated carrier signal. A demodulator for detecting the envelope which switches a switching transistor ON during the mark portions of the modulator carrier signals and switches the switching transistor OFF during the space portions. A parallel resonant circuit is driven by the switching transistor to produce a.c. modulations to be coupled to a full-wave rectifier. The rectified voltage of the rectifier is used to energize an electromagnetic relay.

Discharge lamp lighting device

Abstract: Discharge lamps are connected to a commerical alternating current power supply through an impedance for blocking high frequency signals and an impedance compensating for the negative resistance of the discharge lamps. The discharge lamps are also connected to the commercial alternating current power supply through a rectifier and oscillator circuit, a voltage signal is generated including the commercial alternating current voltage superposed on a high-frequency, high-voltage signal from the oscillator. This voltage signal is applied to the discharge lamps to energize the same and maintain the lamps in a lighted condition.

Rectifier circuit diode array and circuit protector

Abstract: In a rectifier circuit structure, particularly for automative use, a diode array is in the form of a column and includes a Zener diode in the column which serves to protect the rectifier diodes of the arrangement and to protect an electrical load system coupled to the output of the diode array.

High voltage rectifier for television receiver sets

Abstract: In a high voltage rectifier for use in a television receiver set, a resistor block is incorporated therein to produce focusing and screen voltages, and a focusing voltage feeder for supplying the focusing voltage to a cathode ray tube is covered by a screen voltage feeder for supplying the screen voltage to the cathode ray tube to form a unitary high voltage insulated cable.

Full wave rectifier

Abstract: A full wave rectifier includes an operational amplifier (22) having an inverting terminal (36) connected to the emitter of a transistor (30). Afirst resistor (32) is connected between a first power source (VCC) and the collector of the transistor (30). A second resitor (34) is connected between a second power source (-VEE) and the emitter of the transistor (30). When the first and second resistors have an identical value and first and second power sources have same absolute voltage but opposite polarity, the voltage on the transistor collector represents the rectification of the voltage (VIN) applied to the non-inverting input (24) of the operational amplifier (22).

Electronic sensor on/off switch

Abstract: Electronic sensor on/off switch for a load connected to an a-c supply network, including a controlled semiconductor switch connected in a series circuit with the load, a sensor for switching the load on and off, a control circuit connected from the sensor to the switch, the switch being addressable by the control circuit in a conducting state with the load switched on by a signal holding the switch in the conducting state at the zero crossing of a current passing through the load, and in a non-conducting state with the load disconnected by signal switching the switch into the conducting state for switching on the load at the zero crossing of an output a-c voltage at the switch, a power supply circuit connected to the control circuit, a current transformer having a primary and a secondary winding and being operable in saturation, the current transformer being connected in series with the switch, the control circuit including a first rectifier being coupled to the secondary winding and having an output producing a supply voltage with the switch in the conducting state relative to a reference potential equal to a reference potential point of the output a-c voltage, and a branch of the series circuit including the primary winding, the switch, a storage capacitor chargeable by the output a-c voltage and a second rectifier producing the supply voltage in the non-conducting state.

Sewing machine drive

Abstract: A sewing machine drive having a mains rectifier (1) which, via a chopper (2) operating at a relatively high frequency, supplies direct current pulses to the driving motor (3). The duty ratio of these driving pulses is controlled as a function of a nominal value transmitter (11) and a current limiting circuit (14) controlled by the motor speed. This produces a smooth quiet, vibration-free operation of the motor (3) or the driven machine with a high degree of motor efficiency. Moreover, a speed-dependent current limitation occurs in such a manner that at high speeds a limited maximum current flows, which at the same time results in an output limitation.

Modelling Rectifier Loads for a Multi-Machine Transient-Stability Programme

Abstract: An improved rectifier load model for use in transient-stability studies is developed. The model, which simulates abnormal modes of operation and the dynamics of the d.c. load, is used to investigate the stability of a power-system where the rectifier can represent a large percentage of load.

Inductive heating appts. for e.g. welded pipes - has controlled rectifier networks supplying adjacent inductors coupled to common firing control

Abstract: The heat treatment appts. uses a number of inductors associated with respective current suoplies, each comprising a current converter connected across the mains network. Each current converter has an AC/DC converter and a DC/AC converter using controlled semiconductors e.g. thyristors or triacs. These receive firing pulses from a common pulse generator which is controlled by a regulator in response to the measured extinction time or extinction angle. These are fed to the regulator from each DC/AC converter via an extreme valve selector. The firing control prevents cross influences on the workpiece being treated from adjacent inductors. The heating appts. can be used for metal pipes with a longitudinal welding seam.

Insulation resistance measuring device

Abstract: PURPOSE:To use a lower-cost amplifier for the titled device by inserting a voltage dividing resistance circuit, which has a prescribed voltage dividing ratio, into the grounding wire and by connecting both ends of the resistor having smaller resistance values to the device. CONSTITUTION:A voltage dividing resistance circuit consisting of resistors 8 and 9 are inserted into the grounding wire EL, and an insulation amplifier 7 is connected to the output side of the outputting resistor 3. The output of this amplifier is applied to the resistor 9 which has a smaller resistance value. If the resistance value of the resistor 9 is set to, say, 1/20 that of the resistor 8, the voltage across the resistor 9 can be suppressed to about 10V, even if a higher harmonic voltage of about 200V is induced across the voltage dividing circuit by the rectifier circuit 6. The amplifier which can withstand such a voltage is easily and cheaply available. The harmonic voltage across the resistor 9 is not transmitted to the outputting resistor side, because the amplifier 7 lies in between. The higher harmonics which have occurred at the detecting resistor 4 is removed by the filter provided on a measuring device 2. Through this constitution, a lower-cost amplifier is available.

Zero voltage switching AC relay circuit

Abstract: A zero voltage switching circuit for controlling current to a serially arranged load and AC voltage source including first and second photosensitive silicon controlled rectifiers having a gate, anode, and cathode terminals, the anode-cathode terminals being arranged to be connected in inverse parallel across the load and AC voltage source, apparatus for applying input signals to generate light to enable the first and second photosensitive silicon controlled rectifiers, apparatus for providing a voltage range within which the photosensitive silicon controlled rectifiers operate, apparatus for clamping the gate terminals of each of the photosensitive silicon controlled rectifiers to its cathode in the absence of input light signals to the photosensitive silicon controlled rectifiers, and apparatus for opening the circuit between the gate and rectifier of each photosensitive silicon controlled rectifier in the presence of input light signals.

Measurement of Input Power of DC Motors Operated Using Rectifier Power Supplies and Choppers

Abstract: The significance of measurements of the ac and dc components of input power of shunt-and series-wound dc motors operated from rectifiers is presented. Suggestions are given to check and improve the degree of accuracy of power measurements using conventional moving-coil wattmeters. A newly developed electronic wattmeter is described which has been found to provide improved accuracy in rectifier applications. Test results are presented.

Phase rotation detector

Abstract: PURPOSE:For preventing the dispersion of parts in characteristic and the influence of the frequency for example of three phase power supply, to generate ignition signal for a phase control type rectifier device almost in synchronization with the zero point of the voltage between given terminals for three-phase power supply. CONSTITUTION:Rectangular wave voltage is generated by a Zener diode 7 during the semi-cycle while the voltage of a terminal 1b becomes positive with respect to a terminal 1C. the differential signal of said rectangular wave voltage appears at the both ends of a resistor 13. The differential signal generated on the rise of said rectangular wave voltage has positive polarity with respect to the gate of an SCR 5. In the meanwhile, the negative differential signal generated on the fall of said rectangular wave voltage is shorted by a diode 15. The ignition signal generating means 100 made of said Zener diode 7, a condenser 14 and a resistor 13 ignites an SCR 5 almost in synchronization with the zero point of power supply voltage V1b-1c.

Calculation of rectifier-circuit performance

Abstract: Approximate formulas for the calculation of the output voltage, ripple voltage, and the r.m.s. and peak values of the source current of bridge, and one- and two-phase halfwave rectifier circuits are presented. These have been derived by replacing sines and cosines by the first two terms of their series expansions. It is shown that the approximations made introduce errors which, in the great majority of practical applications, are less than 1%. Brief comments on the practical application of the formulas are made, and some calculated and measured values of the output and ripple voltages presented, showing good agreement.