Abstract: A method and system for compensating for voltage notches in phase locked loop (PLL) control devices. A bridge firing controller receives signals representative of two of the line to line voltages received by the bridge. The controller includes a PLL synchronizing tool which receives the line to line voltage signals and generates a synchronizing phase error signal for aligning the phases of the two input signals. The controller, for a predetermined period following bridge firing, determines whether a voltage notch has occurred. If so, the controller substitutes model control signals for actual control signals so as to reduce the effect of the notch on the generated phase error signal used for synchronization. If not, the controller continues to use the actual control signals to generate the phase error signal. Once the predetermined period has expired, the controller utilizes the actual control signals to generate the phase error signal.

Abstract: Switching losses are distributed equally between multiple switching devices in a rectifier bridge (50) in which the rectifier bridge comprises at least a first pair of serially connected switching devices (56A, 56B) connected between positive and negative DC output buses (52, 54) and a second pair of serially connected switching devices (58A, 58B) connected in parallel with the first pair of switching devices. Only one of the switching devices in each pair of switching devices is pulse width modulated at any time at a frequency substantially higher than a frequency of the AC power applied to the rectifier bridge while another of the switching devices in each pair of switching devices is operated in synchronism with the waveform of the AC power applied to the bridge. Operation further involves periodically alternating the PWM operation of the switching devices between switching devices in each pair of switching devices so as to distribute the losses.

Abstract: A three-phase controlled rectifier bridge for converting alternating current to direct current includes six segments for each of the positive and negative polarities of each of three AC phases. Each of the segments has a semiconductor controlled rectifier element responsive to a control signal to control current conduction within the segment. A conduction monitor, which is provided for each of the AC phases, monitors a corresponding one of the AC phases to provide a conduction monitor signal. A first shunt current sensor senses current of the segments for the positive polarity of the AC phases and provides a first current signal. A second shunt current sensor senses current of the segments for the negative polarity of the AC phases and provides a second current signal.

Abstract: A parallel array of a plurality of controlled rectifier bridges for converting multi-phase AC current to DC. Each bridge includes a plurality of rectifier segments. One segment for each polarity of each phase of current. A sensor monitors the current and temperature at each rectifier. The sensor outputs for corresponding segments among the bridges are compared and the timing of the conduction of the rectifiers are controlled to maintain the current and temperatures among the corresponding segments in balance.

Abstract: In a power converter apparatus having a three-phase AC power supply connecting unit, a positive side capacitor, a negative side capacitor, first-phase and third-phase converting circuits each including switching elements connected in series, and a common phase for connecting a neutral polarity to a second phase, there are provided a common phase converting circuit including two switching elements connected in series between positive and negative polarities, a change detector for detecting a temporal change of an electric current flowing through the common phase, and a duty controller for changing the on-off duty of the switching elements in the common phase converting circuit on the basis of the temporal change.

Abstract: The present invention converts an alternating current input into a direct current output by switching a current load at high speeds to create a voltage envelope having a maximum allowed voltage and a minimum allowed voltage. Complementary switching elements are employed to take advantage of both the positive and negative portions of an AC cycle. Load switching is arranged so that the current vector which represents the load is nearly coincident with the voltage vector which represents the power source. The system can operate in an open loop mode at a constant frequency, in a closed loop mode, or in a hysteresis mode. During open loop operation, the voltage envelope is not rigidly defined as the switching frequency remains constant. During hysteresis mode control, the voltage envelope remains fixed and the current switching frequency varies.

Abstract: A capacitor precharge circuit limits both peak DC link current and peak AC line current to any desired peak magnitude thereby providing for optimum precharge control and robust operation. The precharge circuit employs a microprocessor which implements a non-linear discontinuous current control scheme without the need for current sensors. The precharge circuit is well suited for use with an AC to DC converter having link inductor and a DC bus capacitor which requires precharging before full power is applied to the converter.

Abstract: A power generation system is constituted by an induction generator and a converter. An output current waveform of the induction generator is determined by the magnetic flux, speed, winding impedance, DC output voltage, and load of the induction generator. In particular, the output current waveform is changed in accordance with a change in speed (i.e., change in slip). Switching elements in the converter are ON/OFF-controlled in accordance with changes in current waveform, thereby controlling power generation of the induction generator.

Abstract: A circuit and method for converting three-phase .DELTA. AC to a higher voltage DC output. The method utilizes first, second and third rectifying circuits and a storage circuit to provide DC. The circuit herein does not require an independent DC power source, nor a neutral AC connection, as used for conventional Y connected power systems. The circuit herein also provides a uniform loading to all three phases of the AC input. A preferred embodiment is provided herein comprised of twelve diodes and three capacitors, wherein the diodes rectify the current, and the capacitors store charge.

Abstract: A novel switching rectifier circuit that combines the conventional three-phase, 6-stepped PWM rectifier/inverter circuit with a simple, low-power switch commutation circuit to provide zero-voltage turn-on for the switches, and soft turn-off for the diodes. The main features of the new circuit include elimination of switching losses on the power switches and reverse recovery problems on the diodes, elimination of the need for any snubbers in the three-phase bridge, possibility of use of slower diodes in the power bridge, constant frequency operation, and no increase in component current and voltage stresses over the conventional PWM rectifier.

Abstract: An AC/DC converter is provided for connecting to conductors of a multi-phased alternating current generator or network, which is built redundantly for protection against a total loss and which loads the AC generator essentially without non-linear distortion and where several power factor correction circuits, arranged in parallel with one another, are provided. A number of rectifier circuits are included which are independent of each other and equal to the number of phases of the generator. Each rectifier circuit has six rectifier elements which are connected in pairs to terminals of the generator and, by the formation of bridges, are commonly connected to the output conductors of the rectifier circuits. Each rectifier circuit is connected to a one phase power correction circuit. At least one switch is provided for each rectifier circuit.

Abstract: A three-phase, pulse-width-modulated, switching rectifier, with zero-voltage-switching.

Abstract: A power converter for converting input AC power comprising N phase-to-phase input AC waveforms at a first frequency into overall output DC power, where N is an integer greater than two, includes N phase-to-phase AC/DC converters each receiving a phase-to-phase waveform and having outputs connected in series whereby the converter outputs are combined to develop the overall output DC power. The AC/DC converters are operated such that a parameter of the input AC power and a parameter of the overall output DC power are controlled.

Abstract: In order to initiate the automatic regulation of the operating current of a current source in a power supply unit upon closing the operating load circuit connected to the current source, it is proposed that the current source is controlled by presetting the circuit parameters such that the current flowing in the operating load circuit upon closing the operating load circuit reaches a preset or desired value. The current regulation is brought into effect as soon as the difference between the effective value and the preset desired value of the current flowing in the operating load circuit falls below a predetermined threshold value. For this purpose, a regulation circuitry is provided, comprising a voltage regulator, a current regulator and a switching circuitry with a threshold value circuit. The switching circuitry generates a switching signal which effects the change from the initial voltage regulation to the subsequent current regulation as soon as the operating current exceeds a preset value.

Abstract: The invention concerns a high power power supply with output power in excess of 5 kilowatts, by way of example, for the supply of electromagnets in the area of electromedicine and nuclear physics. In order to regulate the output current, power thyristors 28 are utilized within the two bridge rectifier circuits 2 and 3, operated with phase control regulation. In order to keep the output current constant, two transistor final control elements 10 and 11 regulated by a control-gain amplifier are used. Two charging capacitors 6 and 7 are provided for energy storage, the capacity of which is sufficiently large that the commutation of the power thyristors 28 transpires by means of self-extinguishing in a currentless state, whereby conducted as well as irradiated electrical interferences are eliminated.

Abstract: A semiconductor power conversion system comprising a multiphase bridge circuit which includes semiconductor devices having a controllable firing function and a reverse blocking characteristic, a gate control circuit which gives firing commands to the semiconductor devices, a short circuiting switch in which switching devices having a controllable firing function and a reverse blocking characteristic are connected in parallel with a DC output side of the multiphase bridge circuit, and a protection control device for performing a control for protecting the multiphase bridge circuit.

Abstract: A multiplex transmitter-receiver system comprising a synchronizing signal generator for producing a plurality of multiplex transmission-receiving synchronizing signals from a three-phase alternating current, and a signal processor for effecting signal processing based on the synchronizing signals for transmitting and/or receiving a plurality of signals through a single signal transmission line. The signal generator comprises a polyphase rectangular wave generator for producing polyphase rectangular waves by shaping the waveform of the three-phase alternating current, and an arithmetic logic unit for producing a plurality of multiplex transmission-receiving synchronizing signals by logic elements based on combinations of the polyphase rectangular waves.

Abstract: In a current transformer arrangement for three-wire three-phase systems, use is made of a single busing transformer (4) arranged on the three-phase side. Two of the total of three phase conductors are pushed through the bushing transformer, specifically either with the same number of turns per unit length and in mutually opposite defined directions or with the same direction and with the ratio of different numbers of turns per unit length of 2:1 or with the same direction and a current flow halved in a phase conductor by a shunt (15). These arrangements prevent the occurrence of a zero resultant magnetic flux. The double secondary voltage produced by a double AW value occurring twice during each period is halved by an electronic correcting circuit. The control commands are derived from suitable control pulses for the thyristors (21-26) of the three-phase bridge circuit (16). Two correcting circuits are specified.

Abstract: In a control apparatus for controlling the firing timing of each of thyristor valves constituting a thryistor bridge by use of at least two series of control systems, a bypass-pair control circuit for thyristor bridge includes a circuit for detecting the conduction states of the thyristor valves, and a circuit for determining a conductive valve at the time of bypass-pair operation in accordance with a result of detection of the conduction state of each thyristor valve.

Abstract: There is disclosed a method for detecting thyristor conduction using voltage sensing means (400) rather than prior art current sensing means (112). Circuitry for protecting back-to-back thyristor bridges (300) is also disclosed having two levels of protection. One level comprises circuitry (540) for detecting firing commands to the bridges. When such commands to one bridge are detected, the circuitry is operative to prevent the transmission of firing commands to the other bridge. The other level of protection comprises circuitry (400) for detecting conduction by any thyristor in the bridges (300). When conduction by a thyristor in one bridge is detected, the bridge conduction detection circuitry is operative to prevent the transmission of firing commands to the other bridge.

Abstract: A three phase A.C. to single phase A.C. converter wherein the output voltage is not disturbed if one of the input phase lines becomes inoperative. The three phase A.C. is first rectified, and a D.C. voltage is derived from the resulting rectified D.C. current. The D.C. voltage is regulated, and a single phase A.C. voltage is generated from the regulated D.C. voltage.

Abstract: A full wave rectification circuit for use with a three-phase input signal connected in a wye configuration for rectifying a line to neutral high input voltage is disclosed. The rectification circuit has two portions. A first portion generates a control signal which oscillates every 60.degree. and is switched in phase with one of the input signals. A second control signal, also oscillating in 60.degree., but completely out of phase with respect to the first oscillating signal is also generated. The two oscillating signals are used in a SCR switch configuration to switch the rectification circuit every 60.degree. thereby rectifying the peak voltage portion of each phase.

Abstract: A power supply incorporating a fault detection circuit controlling a circuit breaker is described. The power supply is isolated from relatively large applied DC voltages. This isolation is provided by a coupling capacitor in each of the line leads. The tripping energy for the circuit breaker can be provided either directly from the full wave rectifier output, or directly from the line lead or leads. In the case of the former, a reservoir capacitor may be used for storage of charge for tripping of the circuit breaker.

Abstract: Circuitry and methods are provided for AC line synchronization of the firing means for phase-controlled thyristors in a DC motor speed control system. A line synchronization method and system is disclosed which eliminates zero offset in the phase command input function. This zero offset, which is cuased by motor counter EMF, occurs in prior art controllers which use zero crossings of the AC line voltages for line synchronization of thyristor firing. This invention provides line synchronization timing intervals of constant duration that terminate at the coincidence of AC line voltage and motor counter EMF with the coincidence being the latest time at which the particular thyristor being controlled is forward biased in the absence of current flow. Application to N-phase AC to DC converters for DC motor speed control is disclosed.

Abstract: A circuit arrangement for supplying a load (15) with energy from a power supply mains (1 to 5; 21, 22, 23) conveying at least one alternating voltage (UW; R, S, T) includes a simple network to ensure both a uniform energy supply of the load (15) and a reliable suppression of interference from the load to the power supply mains and in the reverse direction by means of a rectifier arrangement (7 to 10) which for each terminal (4, 5; 21, 22, 23), of the power supply mains includes a rectifier stage (7, 8; 9, 10; 24, 25; 26, 27; 28, 29) constituted as a first branch of a bridge rectifier. For each rectifier stage an energy storage device (11; 12; 30; 31; 32) can be charged by and is connected to said stage in accordance with a complementary branch of the bridge rectifier. For each stage a switching element (13; 14; 33; 34; 35) is provided for connecting each energy storage device to the load.

Abstract: A large magnetic separator for separating magnetic fines from nonmagnetic product is equipped with a dual mode power supply. A first mode of the dual power supply is provided for accelerated imposition of the design magnetic field. A second mode of the dual power supply is provided for the maintenance of the desired magnetic field at an improved power factor, which field is in the range of 20 kilogauss. With the field imposed, a canister centrally placed in the magnet with a magnetic stainless steel wool matrix separates magnetic fines from nonmagnetic product until the matrix is saturated. Upon saturation of the matrix, the power supply dissipates to the power grid electrical energy from the collapse of the magnetic field. There results a larger classifying duty cycle of the high stationary magnetic fluid utilized for classification.

Abstract: An adaptable current regulating system provides a regulated current in accordance with both the actual characteristics of a system under control and the actual measured period of an AC supply. The system constantly monitors its status, and provides a master controller with the status of the system, and is programmed to provide control in accordance with information received from the master controller.

Abstract: A control system for an industrial inverting type power supply is disclosed which provides for both operational control and a diagnostic capability for the power supply. The operational control aspects includes measuring and displaying a plurality of operational signals from within the power supply, and for providing several automatic modes of operation for the power supply. The diagnostic aspects of the control system include measuring and displaying a plurality of diagnostic values, particularly the measurement of several waveform characteristic values of the switching waveform of the power supply. Other diagnostic capabilities include a set of remote inputs, each of which, when activated, triggers an entry into a history table, thereby maintaining a record of remote input activations. Each remote input may also be configured with a descriptive message to be displayed on an operator display and a code which specifies the action that is to be taken by the control system when that remote input is activated.

Abstract: In the rectifier station (GR), the reference d-c current (J.sub.w) is automatically formed from the differences of a reference current-dependent control angle function and the current controller-dependent control angle (A) on the rectifier side, where the actual d-c current (J.sub.d) is termined by the power-dependent bucking voltage in the inverter state (WR), and that in the latter the difference of the actual d-c current (J.sub.d) and a reference d-c current obtained from the reference power (P.sub.W) through division by the actual d-c voltage (U.sub.d) influences a controller which sets the reference d-c current for the voltage controller (UR) in the inverter station (WR).

Abstract: In order to maintain in a rectifier or an inverter, operation with a constant terminal d-c voltage in the event of an asymmetry of the network on the a-c side, the present invention provides a voltage analyzer which determines an asymmetry signal with which a given control angle is modulated. For an inverter, the modulation is accomplished by the formula cos=(-U.sub.= .multidot.cos .sub.0 -2.sub.dx .multidot.i.sub.d)/.vertline.U(t).vertline., where U.sub.= =.vertline.U'.vertline.-.vertline.U".vertline. is the difference of the co-rotating system amplitude and the counter system amplitude and gives the maximally attainable d-c voltage values and U(t) (the instantaneous amplitude of the fundamental system). The d-c voltage is thereby limited to the value U.sub.= and contains no variations caused by the network asymmetry.

Abstract: An electric power converter operable by means of a rotating or moving magnetic field having a substantially constant flux density or of a substantially constant magnitude. The electric power converter functions as a AC to DC, DC to AC or DC converter, or as a phase changer/phase shifter or a voltage adjuster. A feature of the converter is the continuous supply of power from the primary phases in contrast to prior art converters in which only the phase having the highest voltage supplies power at any one time. Harmonic current distortion is, therefore, substantially reduced.

Abstract: A control circuit for generating gating signals to drive the SCRs of an AC switch coupled between a three phase AC source and a three phase load. A reference voltage signal is derived from the source and, after filtering, is applied to a squaring amplifier. The amplifier output is applied to a phase-locked loop (PLL). The output signal of the voltage controlled oscillator (VCO) of the PLL is fed back to the phase comparator thereof via two dividing counters. The output of one counter is applied to a logic block for generating a ramp reset signal in phase with a selected source phase-to-neutral voltage. The ramp reset signal is applied to a ramp forming circuit the output of which is applied to a first input of a comparator. The comparator receives a DC control voltage on its second input and provides on its output a gating signal corresponding to the source selected phase.

Abstract: A power converter apparatus comprising an initial voltage-setting circuit by which a signal for generating a predetermined voltage on the alternating (A.C.) side of a converter is applied to a current negative-feedback circuit at the start of the converter.

Abstract: In a load commutated induction motor drive stability is achieved in a runaway situation by generating in response to the motor speed reference signal a signal representative of the desired power factor angle and in using such signal to delay by that much the gating pulses controlling the current-sourced inverter.

Abstract: An apparatus for controlling power conversion from alternating current (A.C.) to direct current (D.C.) by a converter has a D.C. voltage detector connected to receive a D.C. output of the converter for detecting the D.C. side voltage of the converter, a phase detector connected to an A.C. power source for detecting the phase of the A.C. power source, and calculating means for making a first calculation of a first current command value based on the output of the D.C. voltage detector, a second calculation of a phase angle of the A.C. power source voltage based on the first current command value, and a third calculation of second current command values based on the phase angle of the A.C. power source voltage and the output of the phase detector.

Abstract: An automatic overvoltage protection circuit is provided for an electrical power supply of the type comprising a variable speed three phase alternator (50) having a permanent magnet rotor and three stator output windings (51, 52 and 53), a gated three phase rectifier bridge (60) connected to the three stator output windings and producing a d.c. output voltage, and a control circuit (120) for supplying gating signals at controlled firing angles to the gated three phase rectifier bridge. The control circuit includes first, second and third reference circuits (73, 74 and 75) each including a resonant LRC circuit and connected to a respective one of the three stator output windings, a gating logic circuit (135) connected to the first, second and third reference circuits and providing six outputs, feedback means (122) connected to receive the d.c.

Abstract: The invention relates to an AC voltage supplied rectifier circuit with a downstream smoothing capacitor. A prior art problem with this type of circuit was that the inductive impedance of the supply voltage caused a practically umdamped oscillation between the inductive supply impedance and the smoothing capacitor during start-up which caused the voltage to rise to about twice the stationary value. A rectifier circuit is provided which substantially prevents the over-oscillation having at least one controllable rectifier which brings the rectifier to a conductive state during the charging period of the smoothing capacitor over such a time that the output direct voltage of the rectifier circuit exceeds the momentary capacitor voltage by no more than a predetermined limited value.

Abstract: A method of controlling a six pulse bridge phase controlled rectifier using a microprocessor is provided by the invention herein. The method involves synchronizing an oscillator to the frequency of an ac power source and driving first and second counters with the oscillator. The first counter is used in conjunction with a phase locked loop to monitor and adjust the oscillator frequency. The count of the second counter generates an .alpha. value used in a firing angle match routine. The match routine compares the desired output voltage to the cosine of .alpha. minus an inductance factor. The match routine takes less than 20 microseconds to run allowing a new .alpha. value to be checked every 0.5 degrees for a 60 hertz power source. When a match is found, the thyristors are fired and a reload value projecting a subsequent firing in 60.degree. is calculated for the second counter.

Abstract: An improved converter for converting a multiple phase variable frequency AC voltage having a high degree of noise produced by a variable frequency multiple phase voltage source into a DC voltage is disclosed. Triggering pulses for a full wave recification bridge are generated by a low pass filter which filters an output signal from the multiple phase variable frequency voltage source which introduces a constant phase shift independent of frequency. A rectangular wave form is produced having a frequency synchronized with zero crossing points of the output signal from the filter. A digital phase shift compensator phase shifts the rectangular wave form to produce a timing signal having a fixed phase shift throughout the variable frequency range which compensates for the phase shift introduced by the filter.

Abstract: A circuit for regulating the output of a DC power supply that substantially eliminates turn-on transients induced by the switching of a silicon-controlled rectifier (SCR). A zero-crossover detector senses the AC voltage waveform of an applied power source and provides a trigger signal at the zero-crossing point. The trigger signal is applied to cause induction of the SCR's and raise the output voltage when the power supply output drops below a regulated value, and is interrupted so as to inhibit conduction of the SCR's and decrease the output voltage when the power supply output exceeds the regulated value.

Abstract: A power supply apparatus, in which the three phases of an alternating-current main are connected each through rectifier elements connected in antiparallel to the primary winding of a three-phase transformer. The secondary windings of this transformer are connected through rectifiers to a load device, such as an electron beam gun or other such device which produces short-circuits while in operation. Measuring sensors are provided on the primary AC side which, in the presence of an excess current on the primary AC side, block controlled rectifier elements. The blocking takes place very rapidly because GTO thyristors are used as rectifier elements. The decay of the magnetic energy in the transformer is achieved by the fact that the primary side of this transformer is connected in delta.

Abstract: A permanent magnet rotor type electrical alternator-SCR power supply having a unique series resonant LC circuit connected to the alternator and resonant close to the lowest expected frequency of the alternator.

Abstract: An apparatus of the invention includes an AC power source for providing AC electric power, a thyristor converter, being formed of self-extinctive switching elements, for converting the AC electric power to a DC excitation current, a coil for storing magnetic energy corresponding to the excitation current, and a bypass circuit coupled in parallel to the coil. The above appartus uses a method having the steps of: (a) circulating the excitation current between the thyristor converter and the coil when the excitation current reaches a reference value, and (b) commutating the circulated excitation current from the thyristor converter to the bypass circuit after a given elapsed period of time from when the excitation current reaches the reference value, so that the coil generates a high voltage or induces a large current corresponding to the magnitude of the stored magnetic energy.

Abstract: In order to produce direct voltages with greater flexibility, a rectifier (1) according to the invention comprises an alternating voltage measuring sensor (25), a comparator (22), controllable switches (160 to 183) and a switch control (20), through which the switching states of the switches are alterable in dependence on the output signal of the comparator, in order so to connect at least one of the direct voltage outputs (11, 12, 13) for certain time spans during each alternating voltage phase one after the other with the alternating voltage inputs of the rectifier that a pulsating direct voltage drops at it relative to a fixed or variable direct voltage potential. The switching instants are determined through constant measurement of the instantaneous alternating voltage values and their comparison with predeterminable direct voltage levels or alternating voltages, which serves as reference values.

Abstract: A microprocessor determines the zero cross-over times and direction of the phase voltages of the AC power line; a multiplexer has three parallel inputs which are respectively connected to the three phase conductors of the line and an output delivering a voltage formed by successive portions of the phase voltages; a flip-flop sensitive to the change of sign is connected to the output of the multiplexer; and EXCLUSIVE OR gate has an input connected to the output of the flip-flop and an other input to an output of the processor; and a NAND gate has an input connected to the output of the EXCLUSIVE OR gate and another input which receives a signal formed of a succession of square waves forming enabling windows.

Abstract: A regenerative d-c power supply comprises a bridge rectifier, a series-connected smoothing choke, a shunt-connected filter capacitor and a switching circuit consisting of a first diode disposed in a positive line of the d-c power supply between the smoothing choke and one terminal of the capacitor, a second diode disposed in a negative line of the power supply between another terminal of the capacitor and the rectifier and a pair of converter valves in the form of transistors connecting the cathodes of the diodes to one another and the anodes of the diodes to one another. Each converter valve is operated in the forward energy transmission direction by a respective first pulse sequence having pulses staggered in time with respect to the pulses of the other first pulse sequence. The converter valves are operated in the reverse energy transmission direction by respective second pulse sequences each having pulses staggered in time with respect to the pulses of the other second pulse sequence.

Abstract: A process and device are provided for determining the mean value of the current delivered by a thyristor rectifier bridge fed by a multiphase AC network. Said device comprises successively an operational amplifier whose inverting input receives a signal representative of the current supplied by the bridge and is connected to its output by a capacitor, a blocking sampler and an analog-digital converter. The switch and the blocking sampler are controlled by a microprocessor so as to obtain an integration cycle and end of cycle sampling during a period zone of value (T/6), (T) being the period of the network.

Abstract: A ramp generator includes a master counter repeatedly ramping through for ramp-intersect operation of a digital pulse generator, while firing at the intersection, or when above the reference will cause a complementary digital change to define with the master counter count a ramp count on a subsequent ramp and adjacent zone below, thereby to adjust rapidly to a fast change of reference.

Abstract: A new method and apparatus for controlling the conversion of AC electrical energy into DC electrical energy. A microprocessor control system is operatively connected to an AC source and to a motor/regenerative switching bridge network. A control signal is operatively coupled to the microprocessor to selectively adjust the DC output voltage. The microprocessor monitors the control voltage, calculates the timing of gating signals and generates gating pulses to the bridge networks. The microprocessor also senses the phase rotation and the line frequency of the AC source and factors those parameters into account when determining gate pulse output pattern and timing.

Abstract: Disclosed is a control circuit for a power converter apparatus using self-extinction devices as switching devices, in which turn on and turn off operations of the self-extinction devices are controlled by gate pulses which have been subject to pulse width modulation with a pulse train having a pulse width which is sinusoidally varied, and, at the same time, the self-extinction devices in same phase are made conductive in a predetermined period corresponding to an output voltage reference value to make an output of the power converter apparatus be in a shorted state in the sense of DC current to thereby control the output of the power converter apparatus.