Showing papers on "Precision rectifier published in 1979"

Method and system to supply electrical energy to a self-contained electrical network at multiple voltage level, multiple power range, particularly for mobile application

Abstract: To supply intermittently required high-power loads, such as heater applications in an automotive vehicle, a dual armature winding three-phase alternator has a first or main winding connected to a first or main rectifier bank to supply power to vehicular loads, for example at 12 V nominal level; an auxiliary winding is connected to a rectifier which can be switched to operate as a half-wave rectifier, in parallel with the main winding and main rectifier to supply the ordinary loads when high-power loads are not connected; or to be switched in a full-wave bridge rectifier configuration to provide additional power at elevated voltage, added to the voltage of the rectifier receiving current from the main windings, for example providing 16·√3=28 V added to the nominal supply voltage of 12 V=40 V voltage to the heater load.

Method and apparatus for controlling power and optimizing power factor in an AC-to-DC converter

Abstract: A motor drive system for direct current motors and other similar loads in which the power factor presented to the line by the system remains close to unity for all operating conditions (e.g., all motor speeds). This is accomplished by rectifying an alternating current input voltage and thereafter chopping it to vary power input to the load. An important feature of the invention is the use of a choke at the output of the rectifier of sufficient size to insure that current pulses flowing from the rectifier will be continuous (i.e., will not drop to the zero voltage level) during the sequential ON periods of the rectifier elements.

Peak detector circuit

Abstract: A peak detector circuit particularly adapted for recovering timing and data information in a binary recording system. The circuit comprises an operational amplifier having a diode-plus-resistor bridge network in a negative feedback path from the output of the operational amplifier to its inverting input. The non-inverting input of the operational amplifier is connected to a common ground. The signal whose peak is to be detected is capacitively coupled to the op-amp's inverting input and the peak detector's output is obtained at the op-amp's output. The diode bridge network comprises two pairs of diodes connected in series and a resistor to ground from the connection node of the diode pairs; in each diode pair the two diodes are connected in parallel, back-to-back. When a peak is detected, the op-amp output switches between positive and negative saturation values. This circuit has maximum gain at the signal peaks and exhibits decreased gain (and, hence, sensitivity to noise) as the signal moves off its peak; it is fast to detect the presence of a peak and presents a fixed phase delay.

Constant current welding power supply with an upslope starting current

Abstract: A constant current welding power supply having a single transformer with a primary winding connected to a three phase input source of line voltage and two secondary windings each having a bridge rectifier for providing an open circuit starting voltage separate from the arc working voltage. Each bridge rectifier is fired by separate firing means controlled by a logic control means. One bridge rectifier is energized with an advancing firing angle proportional to a ramp output signal enabled through the control means in response to a predetermined drop in output voltage. The other bridge rectifier is energized in synchronism with the line voltage for a predetermined period of time following the predetermined drop in output voltage.

Rectifier controller responsive to sensed A.C. voltage signals

Abstract: A rectifier controller for controlling bridge connected silicon control rectifiers (SCRs) (1 to 6) of a three-phase rectifier which is used to supply a direct current (DC) voltage to an inverter (314) used for injecting pulse coded audio frequency signals on a power line. The controller supplies gate control signals to the SCRs (1 to 6) of the rectifier bridge in accordance with the envelope of the three-phase supply voltages and provides for protection of the inverter (314) when shoot-through conditions occur in the inverter (314) and provides for output DC voltage adjustment by controlling the firing time of the rectifier bridge SCRs.

Apparatus for detecting diode failures in multiple diode rectifier bridges

Abstract: A circuit for detecting a failed diode in a multiple diode rectifier bridge detects open or shorted diodes in both multi-phase, half-wave rectification and single or multi-phase full wave rectification arrangements and provides a failure signal for sounding an alarm or tripping the circuit to protect the load or power source as the case may be.

Commutation failure detection and restoration for scr frequency converters

Abstract: OF THE DISCLOSURE A frequecy converter having a silicon controlled rectifier comprises a protection circuit which includes a series resonant circuit connected in parallel with the silicon controlled rectifier to generate a reverse voltage thereacross in response to a short circuit established in response to a commutation failure of the silicon controlled rectifier An inhibit circuit is provided to respond to the reverse voltage by in-hibiting the current flow through the silicon controlled rectifier to allow the same to restore to its locking state

A-C Rectifier circuit for powering monolithic integrated circuits

Abstract: A self-biased MOSFET with suitably biased substrate is used as one of the rectifiers in a rectifier circuit for converting a-c power to d-c power for application to a monolithic integrated circuit of which the rectifier circuit is a part. This avoids the parasitic transistor action which would accompany the use of an isolated pn semiconductor junction, which parasitic transistor action undesirably discharges a storage capacitor connected across the output of the rectifier circuit.

Electric power converter apparatus for an a.c. electric rolling stock

Abstract: A power converter apparatus for an a.c. electric rolling stock comprising two transformers, each including a primary winding and a plurality of secondary windings generating the same output voltages but having different internal reactances; a pair of phase-controlled bridge rectifier circuits, each being connected to one secondary winding of each transformer; and diode bridge rectifier circuits connected to the other secondary windings, wherein the windings connected to the pair of phase-controlled bridge rectifier circuits have different internal reactances, and the phase-controlled bridge rectifier circuits are simultaneously controlled, and when the maximum output voltages from the phase-controlled bridge rectifier circuits are reached, the output voltages from the diode bridge rectifier circuits (non-phase-controlled) are increased to their maximum values, then the output voltages from the phase-controlled bridge rectifier circuits are decreased to their minimum values.

Circuit arrangement for producing a regulated high DC voltage from a three-phase current

Abstract: A circuit arrangement for producing a regulated high dc voltage from three-phase current utilizes a three-phase current bridge rectifier which is connected to lines for the three phases of the three-phase current, and a first circuit having a transistor is arranged parallel to the three-phase current bridge rectifier circuit and includes a base for receiving a control current. In each line of a three-phase supply, a series resistance is connected in front of the connection points of the lines of the three-phase current bridge rectifier.

X-ray diagnostic generator comprising an oil-filled tank with a high voltage transformer and a high voltage rectifier, and an x-ray tube

Abstract: For the formation of an electric signal corresponding to the x-ray tube voltage, the high voltage transformer is provided with a low voltage winding. The low voltage at the terminals of the low voltage winding is conducted to the exterior of the tank. Here, a low voltage rectifier circuit is connected which corresponds in its circuit configuration to the high voltage rectifier circuit so that the electric signal supplied by the low voltage rectifier circuit accurately corresponds to the x-ray tube voltage and can be used for control purposes. The high voltage rectifier circuit and the low voltage rectifier circuit can operate as voltage multipliers.

Automatic gain control system

Abstract: PURPOSE:To make broader the range of automatic gain control and to enable stable operation, by controlling the loop gain which controls the variable gain amplifying circuit with the gain under limit of the gain control loop of the variable gain photo detection circuit. CONSTITUTION:the reception signal is converted into electric signal with the avalanche photo diode APD11, amplification is made with the variable gain amplifier 12 and output is made to the identification circuit 15 and the peak detector 13. When the peak detection output is compared 17 and the voltage control circuit 16 determines the lower limit of the output voltage in advance. The output of the comparator 14 controls the circuit 16. The control loop in which the output voltage is the bias voltage of APD 11 and the control loop controlling the amplifier 12 with the output of the comparator 17 when the output of the comparator 14 is more than a given value, are automatically changed over, holding the reception output level at a constant value. Thus, the range of automatic gain control is made broader and stable operation can be performed.

Universal motor with starting current surge limiter - uses controlled rectifier system with blocking up to half wave of supply

Abstract: The universal motor has a circuit which limits the starting current. The motor is fed with alternating current and its circuit contains a two pole switch with three positions. The current limiting branch (S) contains a controlled semiconductor rectifier system(TH) and a control circuit. This will enable the semiconductor rectifier system to be blocked in each half wave of the supply voltage at least until the maximum voltage occurs. The control circuit is in parallel with the current limiting branch. It contains a control current branch with a capacitor with a leading control current relative to the supply voltage.

Low distortion bridge rectifier current regulator - has drive circuit using electronically controlled switch in potential divider input stage (OE 15.12.78)

Abstract: An alternating current element consisting of a diode rectifier, differential amplifer, and one or more input stageS, has a low distortion factor and is used to drive a current regulator placed in the direct voltage arm of a bridge rectifier. The regulator contains a transistor and resistor. It is designed for partially lossless electronic regulation in the current range 2mA to 20 A with distortion suppression. The input stage is a voltage divider, consisting of an electronically controlled switch (Rx) and series resistor (Rv), connected to a common emitter transistor stage (T, Re) via an operational amplifier (V), the whole being connected to the rectifier bridge (D1-D4) direct voltage connections.

Reactive current generator - has static converter bridge circuits connected on DC side in series in ring

Abstract: The generated current intensity and shape vary quickly. The generator has a rectifier transformer connected to the three-phase network to be influenced, and a rectifier control element, by which controllable rectifier diodes are looped in the same secondary windings of the rectifier transformer, or they are bypassed in a free-running operation. A three-phase capacitor battery is connected in parallel with the three-phase network in order to provide a specified compensation reactive power, and a control device is provided. Network voltage controlled static convertor bridge circuits are used as the convertor control element, connected to secondary windings (1-4) of each secondary winding system. They are connected with each other of the d.c. side, and in series with a smoothing inductor (10, 20, 30, 40). D.c. circuits of all secondary systems are connected in the same sence in series in a closed ring.

Circuit arrangement for the ungrounded transmission of signals across points of isolation in communication systems

Abstract: The invention relates to a circuit arrangement for the ungrounded transmission of signals by separating locations in Femmeldeanlagen means on the primary side of the separation signal controlled high-frequency vibrations which are evaluated on the secondary side of the separation by rectification for reproducing the signals. the emitter-collector path of a transistor, which is connected with a separating transistor in series is used for the secondary-side rectification. This is controlled by signals which are generated by separate rectification of the secondary-side alternating signals. Between the rectifier transistor and the isolation transistor a filter device is arranged, which blocks the output of the shading against high-frequency signal components. For transmission of binary signals two separation points transformers can be provided.

Circuit with a rectifier and a logarithmic amplifier

Abstract: Two circuits known per se, a logarithmic amplifier and an active rectifier, are constructed by means of a single operational amplifier.

Transformer coupling circuit providing for cancellation of D.C. fluxes

Abstract: In a coupling circuit for A.C. coupling a switching network to a trunk circuit through a coupling transformer, a magnetic flux cancel circuit is provided for canceling non-varying magnetic fluxes produced by direct current components of a switch-hold current and a control signal which are applied, respectively, to the primary and the secondary windings of the transformer at its core to each other. The flux cancel circuit comprises a rectifier circuit such as a diode bridge circuit. The rectifier circuit is connected at least between the trunk circuit and the secondary winding of the transformer coupled therewith such that the direction of an output current of the rectifier is predetermined with respect to that of a direct current supplied to the primary winding to cancel the non-varying magnetic fluxes by the direct currents in the transformer.

Protection circuit for acoustoooptic modulator

Abstract: PURPOSE:To surely protect the acousto-optic modulator by branching part of the signal being applied from a power amplifier to the acousto-optic modulator, peak- detecting the same, comparing and amplifying the output there of with a reference voltage and gain-controlling the input signal of the power aamplifier. CONSTITUTION:The carrier from a carrier oscillator 1 is modulated by the picture signal fs by a modulator 2, passes through a gain control circuit 11 and is aiplified in a power amplifier 3, after which it is applied via directional coupler 5 to an acousto-optic modulator 4. At the same time, part of the output signal of the power amplifier 3 is branched by the directional coupler 5 and the peak value thereof is detected with a peak detecotor 12. The output signal of the peak detector 12 is compared and amplified with a reference voltage 14 in a comparing amplifier 13. The output of the comparing amplifier 13 is led to the gain control circuit 11, which lowers the input voltage of the acousto-optic modulator 4 and protects the acousto- optic modulator 4 against excessive input power when any excessive input voltage is applied to the acousto-optic modulator 4.

Gateetype peak detector circuit

Abstract: PURPOSE:To improve a noise-proof property by adding a switching transistor to a peak detector circuit to give a gate function to the circuit and operating the circuit only during the color burst signal imput time CONSTITUTION:Composite chroma signals are applied to the base of transistor TrQ1 throgh coupling capacitor C1, and TrQ3 and this TrQ1 form a differential amplifier Here, pulse signals synchronizing with color burst signals are inputted to TrQ2 connected to the emitter of TrQ3, and a smoothing circuit consistig of resistance R5 and capacitor C2 is provided in the collector of TrQ1 As a result, since switching TrQ2 is added to a peak detector circuit to give a gate function to this circuit, the circuit is operated only during the color burst signal input fixed time, so that the noise-proof property can be improved

Transformer power supply having an inductively loaded full wave rectifier in the primary

Abstract: In a transformer power supply, a full wave rectifier is series connected in circuit with the primary winding of the transformer such that the current flowing through the primary winding of the transformer flows in series through the input of the full wave rectifier. An inductive load is connected across the output terminals of the full wave rectifier such that the rectified output current flows through the inductive load. The full wave rectifier preferably uses silicon controlled rectifiers which are phase triggered in such a manner so as to control their conduction angles so as to control the power flow from the source to the load connected to the secondary of the transformer. The inductance of the load for the rectifier preferably exceeds the critical inductance so as to minimize ripples in the secondary of the transformer. This type of power supply circuit is particularly useful for supplying power to an electron gun which is subject to arcing. The inductive load for the rectifier reduces the transient voltages impressed on the transformer resulting from SCR phase control and also minimizes AC voltage drop across the inductive load while providing transient current limiting as may be encountered by arcing of the electron gun.

Corona discharge intensity measurement device - has circuit sensing difference between peak and average voltage values

Abstract: The undesirable corona discharge which appears irregularly is detected and measured for amplitude by a detector circuit. The peak and average values are determined both for positive or negative voltages. A corona discharge voltage is applied to a detector input terminal (10) and is connected to ground via a measuring resistor (11). The peak value is determined by a circuit (12) comprising an operational amplifier (17) with a diode (18) in the feedback path to form a peak detector. The amplifier drives a second amplifier (19) via a second diode (20) and memory capacitor (21). A leakage resistor (22) allows the measured value to evolve with time. The output of the circuit is applied to a subtractor (15) with an average value from a resistor (13) and capacitor (14) filter circuit. The difference between the two values is obtained at the output (24).

Fault detection system in rectifier installations - operates by comparison of successive current peaks on AC side of equipment

Abstract: Detection of a fault in the rectifier is achieved by measuring the interval between two successive current peaks on the AC side and comparing this time interval with a reference interval for the type of rectifier in service. The failure of a rectifying cell, of a trigger impulse, or a fuse can be detected by this system and an alarm signal is given. The detection circuit can make use of digital techniques and is therefore easily maintained. It can be set up to respond only if a set number of peaks in a given time are incorrect.