Abstract: A plurality of SCR diamond bridge circuits are coupled in series to generate frequencies higher than the individual operating frequencies of the SCR's. The series chain of diamond circuits is preferably coupled in parallel with the series combination of a DC blocking capacitor and an inductive load. The chain is provided with current from a substantially ripple-free constant current source, and the firing times of individual SCR's can be controlled to minimize the di/dt in each SCR.

Abstract: An inverter device operating under pulse width modulation (PWM) principle in which chopping pulse is formed by crossing points of a triangle waveform and a function waveform in order that pulse width of the inverter input current decreases towards later half of pulse train in each period of pulse repetition series so as to make the average input current for each one of the pulses substantially constant.

Abstract: An inverter device operating under pulse width modulation (PWM) principle in which chopping pulse is formed by crossing points of a triangle waveform and a function waveform in order that pulse width of the inverter input current decreases towards later half of pulse train in each period of pulse repetition series.

Abstract: A selective commutation technique used with an inverter eliminates one of the two commutation pulses at those points at which there is a particular relationship of inverter operating characteristics. The power factor angle .theta., the voltage phase angle .delta., and the voltage pattern notch angle .beta. are sensed to determine this particular relationship. Because at the switching point there is no current flowing through the gated thyristor, the gated thyristor can then be transitioned to the nonconducting state merely by the removal of its gate signal. A single makeup pulse is then rung through the system to initialize the commutation capacitors for the next switch point.

Abstract: An LC series resonant regulator is connected across the output of the inverter circuit of a static converter apparatus to vary the output voltage level as the inverter operating frequency varies from a preselected frequency at which the regulator circuit is tuned. The load is coupled across the capacitor element of the regulator and a level detector coupled across the load input. This detector registers variations of the input to the load from a predetermined desired level of load voltage and supplies a feedback signal, indicative of any detected variations, to the control circuit for the inverter circuit element. This control circuit is responsive to a feedback signal to vary the operating frequency of the static inverter so that the regulator varies the output voltage applied to the load to restore the desired voltage level.

Abstract: Disclosed is a class of power converter which extracts electric energy from a source of A.C. or D.C. power and conveys this energy through series resonant circuits to two or more loads in an independently controllable form.

Abstract: A power supply includes an inverter circuit comprising silicon controlled rectifiers which are driven by a variable frequency control signal. The frequency of the control signal is determined by monitoring the power output requirements of the power supply. Because of the continuous sinusoidal operation of the inverter, the supply generates a very low level of radio frequency interference (rfi).

Abstract: A power converter which provides precise waveshape regulation. An input pr waveform (three-phase or single phase power) is rectified and modulated to form a chopped waveform within an envelope defined by the rectified input waveform. The modulation is removed by passing the chopped signal through a low-pass filter. The output of the low-pass filter, which is equal to the instantaneous value of the chopped waveform envelope times the instantaneous value of the duty cycle of the chopped waveform, is converted to a complete sine wave output voltage in a power inverter. The output of the power inverter is sampled and compared with a low-power reference waveform in a differential amplifier. The output of the differential amplifier is phase compensated for the effects of the low-pass filter and applied as an error signal to a pulse-width-modulated oscillator to adjust the duty cycle of the chopped waveform so that the sine wave output voltage follows the reference waveform.

Abstract: With forced commutation static power or current converters having extinguishing or interruption circuit connected to the individual power switching branches and employing controllable extinguishing or turnoff valves, there exists the problem of unsymmetrical voltage build-up in the extinguishing circuits with corresponding overload or overdimensioning of the extinguishing valves, also referred to as commutation valves. This problem is solved, according to the invention, by arranging the usual commutation capacitor between the power switching branches, i.e., the load circuits, and the extinguishing valves, i.e., the commutation valves, and by arranging a damping circuit between the commutation capacitor and the extinguishing valves. The damping circuit is connected, by special valves, with positive and negative limiting potential. The undesired non-symmetry is thus effectively reduced.

Abstract: A static power supply for converting DC power from a source to AC power at relatively high frequencies in a load. The static power supply is particularly useful for supplying power to induction heating loads operating at frequencies of 10 kHz. and higher. The DC supply is connected to supply substantially constant current to a controlled rectifier switching circuit. The controlled rectifiers are gated to produce alternating current in a commutating capacitor. The DC supply and switching circuit are connected to the load via a blocking capacitor so that the AC current component in the switching circuit appears as high frequency AC load current. The circuit arrangement imposes low operating stress levels on the controlled rectifiers, and provides a circuit turn-off time that is relatively independent of load.

Abstract: An inverter circuit, having a DC input and an AC output, has an input circuit portion which includes an isolating diode and an input filter including a choke and a polarized capacitor across the DC input. The DC chopper portion of the inverter circuitry may be either center-tapped--where half of the primary winding is in the circuit at any one time--or bridge-type--where all of the primary winding is in the circuit at any instant. In any event, the chopper portion of the inverter circuit uses SCR's and has 180 electrical degree commutation; with a commutation capacitor across the primary winding of the output transformer and a commutation choke in series with the SCR's. Feedback is provided by feedback diodes which are connected in counter-polarity to the polarized input capacity.

Abstract: A missed commutation detection circuit for use with a power inverter circuit which employs optically isolated gates to provide signals indicative of the state of a pair of SCR power switching devices. The gates are connected to combine the signals via a NOR logic arrangement to generate a missed commutation control signal whenever both of the SCR's are concurrently in a conductive or unblocked condition. The commutation control signal thus generated feeds a one-shot multivibrator which generates an isolation signal for a preselected time period. The isolation signal opens a normally closed current isolation switch connected intermediate the DC input bus and the inverter SCR's which cuts off current to the SCR's permitting them to return to their blocking state. After the duration of the isolation signal from the one shot, the isolation switch is again closed and the circuit is permitted to attempt normal operation.

Abstract: An inverter for diagnostic X-ray equipment, comprising a thyristor bridge with an input diagonal connected in series with two commutating inductances across a DC power supply, is provided with a start-stop circuit which includes an ancillary thyristor connected in series with a diode and a current-limiting impedance across one of the bridge arms. On start-up, the ancillary thyristor is triggered simultaneously with the diagonally opposite bridge thyristor in order to connect the current-limiting impedance in series with the AC output diagonal of the bridge during the first half-period; for a quick cutoff, the ancillary thyristor and the associated bridge thyristor are turned on together whereby two previously charged quenching capacitors, one of them included in the start-stop circuit, are discharged through the commutating inductance in series with the associated bridge arm to terminate conduction in another bridge arm fed through the same commutating inductance.

Abstract: The commutation circuit of an inverter is actuated only when the main thyristors cannot be transitioned to the nonconducting state by the removal of the gate signal. If a commutation pulse is required, the commutation capacitors are charged to the appropriate voltage level immediately prior to the switching point so that they may provide a sufficient pulse of current to extinguish the current through the thyristor. The commutation capacitors are then returned to a stable voltage level until another commutation pulse is required.

Abstract: Performance of an auxiliary impulse commutated inverter is significantly improved by controlling the interval between gating an inverter auxiliary thyristor into conduction for commutation of a then-conductive inverter main thyristor and subsequently gating an incoming inverter main thyristor into conduction as a function of inverter load current. When inverter commutation is commenced, a timing signal generator is actuated, producing a rising amplitude timing signal.A comparator continuously monitors the amplitude difference between the timing signal and a preselected inverter reference firing delay interval signal which varies in accordance with inverter load current. When the amplitude of the timing signal and inverter reference firing delay signal are equal, a bistable trigger resets the timing generator and causes the inverter incoming main thyristor to be gated into conduction, ending the commutation interval.

Abstract: A d.c./a.c. converter synthesizes an alternating voltage by suitably and at the correct instants selectively combining a plurality of direct voltage sources into a variety of series connections by means of a plurality of semiconductor controlled switches and diodes. Polarity inversion is effected with a bridge circuit comprising switches. The converter load is connected to said bridge circuit. In this way it is possible to directly generate a 220 V, 50 Hz AC voltage without inductive elements, from solar panels, using accumulator batteries.

Abstract: One diode each is connected in antiparallel fashion to each load thyristor, said diode being a component of a commutation installation for the corresponding load thyristor. The commutation installation manifests an LC-series oscillatory circuit dimensioned for the specified load current and, for each load thyristor, a controllable commutation thyristor connected to a control circuit. Each commutation thyristor forms a closed circuit with the LC-series oscillatory circuit and its diode. One saturable choke each is connected in series with each thyristor and each diode. One RC-element each is connected in parallel with each thyristor and each diode, and saturation means are present for the chokes associated with the load thyristors. The inverter load may be the high voltage transformer of an x-ray generator.

Abstract: At the initiation of each successive waveform of a train of positive polarity stepped waveforms, a first single-pole-single-throw (SPST) switching circuit is operated for applying this train of waveforms across a fullwave SCR bridge mixer network having individual diodes connected in inverse parallel across each SCR. For alternating ones of the train of waveforms, a different diagonal pair of SCR's of the mixer are turned on at the initiation of an associative waveform, for supplying alternating current to and a dual polarity AC voltage across a load. At the end of the period of each waveform, the first switching circuit is operated for removing the train of waveforms from the mixer, and thereafter a second switching circuit is operated for applying a negative voltage across the mixer network, causing the diodes to become forward biased for reverse biasing their respective SCR's, thereby turning off the conducting ones of the SCR's via natural commutation.

Abstract: A voltage regulating device for a power generating system with inverter circuits including two sets of switching elements each of which is alternately on-off controlled, having delay circuits for controlling delay time in accordance with the load voltage, and characterized in that supply voltage to the load is maintained at a constant level by forcibly turning off either set of the switching elements during the period when the said set of the switching elements are to be turned on.

Abstract: Two or more static converter switching circuits are connected in series across an input voltage source and have their primaries wound on a single power transformer core. Each converter circuit includes a current primary winding so as to limit the current through the power switches during the switching periods. The circuit arrangement allows equal input voltage distribution across the power switches and controls the current rise through each power switch during the turn ON and turn OFF times.

Abstract: A series-type independent inverter comprising a bridge network that includes silicon controlled rectifiers, the bridge network having an a.c. diagonal provided with a circuit comprised of LC-elements, and having a d.c. diagonal provided with a coupling capacitor, and also comprising at least one uncontrolled semiconductor rectifier adapted to limit the voltage across the silicon controlled rectifiers. The inverter includes a saturated ferromagnetic element with a polarized magnetic circuit and with a primary winding inserted in the d.c. diagonal of the bridge network and adapted to form together with the latter a ferroresonance circuit, and also includes a filter tuned to a frequency that is a multiple of the input frequency of the saturated ferromagnetic element and connected to the secondary winding of the element.

Abstract: An inverter circuit comprises a reactor and a capacitor connected in series to a load to supply the load with a series resonance high-frequency power, a secondary winding provided at the reactor, and means for feeding a voltage generated in the secondary winding back to a power supply through switching means of a thyristor. The switching means is made conductive to feed the voltage generated in the secondary winding back to the power supply when supply voltage detecting means detects that a supply voltage exceeds a predetermined voltage.

Abstract: A frequency converter of the series-capacitor type is made substantially insensitive to changes in output load by providing the same with means for limiting the voltage across the transformer and load capacitor or capacitors thereof to a pre-determined value.

Abstract: First and second branches, each containing two thyristors in series, all four thyristors of same polarity, are connected across positive and negative supply lines, in turn connected to positive and negative terminals of D.C. voltage source. D.C. motor connected between junction of two thyristors in one branch and junction of two thyristors in other branch. One pair of diagonally opposite thyristors, or other pair of diagonally opposite thyristors, rendered conductive, for flow of motor current in respective first or second direction. First and second transistors respectively connected in positive and negative supply lines to permit and interrupt thyristor current flow. Selection of a thyristor pair for conduction occurs based on sense of motor-current error. The transistors and selected two thyristors rendered conductive and non-conductive by pulse-width-modulated actuating signal derived from value of motor-current error.

Abstract: An electrical power generating system is provided for supplementing an electrical power distribution network. The supplemental system of this invention is devised to utilize available sources of energy that are otherwise unused and converting that energy to power which is added to and utilized in the normal or primary electrical power distribution network. The system of this invention includes electrical generation means of a type that is adapted to be powered by a specific energy source and develops electrical energy which is stored for intermittent or periodic transfer into the primary power system. An electrical circuit is provided for sensing of the electrical power that is stored and includes a switching circuit that is responsive to the stored electrical power for connecting an electrical energy storage device to the primary electrical network and affect a transfer of electrical power.

Abstract: A naturally-commutated, voltage-fed direct-current (DC) to alternating-current (AC) power converter employing thyristor elements couples a DC power system with an AC power system without the requirement to force commutation. To effect natural commutation, the fundamental component of current flowing between the DC system and the AC system must lead the DC system switching voltage.

Abstract: A current drive circuit for deriving a triangular current waveform for driving an inductive load, such as the field coils of a bubble memory, comprises a series of at least four diodes connected between the positive and negative input voltage lines. A pair of switching devices, such as switching transistors, are connected in series such that each switching device is in parallel with two of the diodes. The junction between the switching devices is also connected to one output for the inductive load. The intermediate diodes are connected together and to one side of a time delay circuit, the opposite side of which is connected to the second output for the opposite side of the inductive load. A modification of the invention comprises a second diode and switching circuit connected between the time delay circuit and the second output.

Abstract: A parallel resonant circuit frequency converter having input terminals of its inverter bridged by an auxiliary commutating arrangement which consists of a bridge circuit of thyristors, the a-c outputs of which are connected to a capacitor in which thyristors of the auxiliary commutating arrangement are fired until a predetermined capacitor voltage is reached to start up the frequency converter, the thyristors of the inverter then fired until a current of predetermined magnitude flows, which is kept contant by control of the rectifier, and subsequently, the thyristors of the auxiliary commutating arrangement are fired prior to each zero crossing of the resonant circuit voltage and, the thyristors of the inverter, delayed by a constant time span, are fired until the resonant circuit voltage has reached a predetermined value.

Abstract: A method of operating a cycloconverter which is adapted for use with a load in the form of a parallel resonant circuit and for use with an intermediate d-c link supplied by an a-c voltage source and including a smoothing choke and a controlled rectifier, the cycloconverter including an inverter circuit comprising a bridge circuit having output terminals adapted to be connected to the load and input terminals adapted to be connected to the d-c link, in which starting of the cycloconverter is realized by firing the thyristors of an auxiliary commutating device for a time interval sufficient to charge commutation capacitors to a predetermined voltage and the thyristors of the inverter then fired for a time interval sufficient to result in a current of predetermined magnitude, the latter being held constant by controlling the rectifier in the d-c link, and, thereupon, prior to each zero crossing of the resonant circuit voltage, first firing the thyristors of the auxiliary device followed, after a predetermined ti

Abstract: A circuit suitable for use in an induction range. The circuit includes a resonant inverter having first and second gate controlled thyristor switches, the main conduction paths of which are serially connected between the power supply terminals. Trigger pulses for the switches are derived from the current supplied to the inverter load coil. The pulses are timed to prevent the first switch from being closed before the second switch has opened so that both switches can never be conductive at the same time. It also includes circuitry for stopping inverter operation in the event of an overcurrent condition and circuitry for adjusting the inverter output power.

Abstract: An electronic power supply utilizes a full wave bridge rectifier circuit whose alternating current voltage source is derived from a multi-primary and multi-secondary winding transformer whose windings are selectively disposed in series or parallel circuits, thereby enabling the apparatus to be effectively employed on a wide variety of A.C. voltage sources. Two adjacent legs of the bridge rectifier employ S.C.R.'s gated simultaneously symetrically by pulses obtained from a unijunction transistor driven by the output of an operational amplifier whose input terminals are coupled to voltage and current sensing networks located at the output terminals of a filter coupled to the D.C. side of the full wave bridge.

Abstract: A circuit for detecting a missed commutation in an inverter. The circuit includes means coupled to the center tap of a commutating interval current limiting reactor which is connected in series with and interposed between a pair of gate controlled rectifiers for generating a first signal upon detecting and for the duration of an interval when both of the rectifiers are ON. The circuit further provides means, responsive to a first pulse used to initiate an interval when either of the pair of rectifiers is to be "ON", for generating a second signal. Also provided is a means responsive to the first and second signals for generating a control signal to cause cessation of the operation of the inverter, if the first signal is absent during the total occurrence of the second signal.

Abstract: A switching circuit, typically a thyristor bridge, is connected to a source of waste energy. The source can be waste energy occurring as a by-product of man's activities such as waste heat energy, stored water, or the potential mechanical energy of elevated objects. The source provides d.c. power either directly or through conversion. The switching circuit is also connected to an a.c. load and across a.c. power mains energizing the load. The switching circuit is operable to periodically connect the waste energy source to the a.c. load in a power supplying manner. The a.c. mains impart suitable voltage and frequency characteristics to the electrical power so supplied. In the event the supplied power exceeds the power required by the a.c. load, the difference is taken by the a.c. power mains.

Abstract: The invention concerns an apparatus and method for starting-up, with the correct phase, a converter having forced commutation. More particularly the converter comprises a power stage having controlled main valves and commutation devices associated with the valves. The converter also comprises a control apparatus which includes a drive unit synchronized with a power line voltage for generating firing pulses for the converter valves and a regulating device preceding the drive unit. In accordance with the invention, at least one energy storage device is charged in the stand-by position with an amount of energy required for commutation. Also in the stand-by position, the firing pulses generated by the drive unit of the continuously running control apparatus are blocked from their respective converter valves. Upon a starting command, the stored energy in the storage device is made available for commutation and the firing pulses are released to their respective valves.

Abstract: A circuit for detecting a malfunction in an inverter. The circuit includes means coupled to the center tap of a commutating interval current limiting reactor which is connected in series with and interposed between a pair of gate controlled rectifiers for generating a first signal upon detecting and for the duration of an interval when both of the rectifiers are ON. The circuit further provides means, responsive to a first pulse used to initiate an interval when either of the pair of rectifiers is to be "ON", for generating a second signal having a duration greater than the normal duration of the first signal. Also provided is a means responsive to the first and second signals for generating a control signal to cause cessation of the operation of the inverter, if the second signal is absent during the occurrence of the first signal.