Abstract: A method and system for dynamic limiting of the pulse width or duty cycle of a switched DC-to-DC power supply. The system includes a first comparator coupled to the voltage to be regulated and to a reference voltage for generating an error signal. The error signal controls the duty cycle or pulse width of a PWM. A limiter circuit includes a further comparator which compares the error signal to a second reference voltage to generate a further limiting feedback signal for application to the first comparator. When the error signal tends to rise above a value established by the second reference voltage, the limiter applies a signal to the first comparator tending to reduce the error signal to thereby prevent the error signal from rising sufficiently to produce the undesired operating condition.

Abstract: A switching power supply such that the step-up ratio of when the power-factor is improved does not increase, and the conversion efficiency can be improved. In a case where the error voltage Ver outputted from a conductance amplifier (23) increases over a reference voltage Vref2, a switching signal of high level is outputted from a comparator (59) to a FET (57) to turn on the FET (57). Therefore a resistor (56) is bypassed, and as a result a reference voltage Vref1 inputted into the conductance amplifier (23) is changed from a reference voltage Vref1-1 to Vref1-2 of lower level. Further, since the variation of the error voltage Ver outputted from the conductance amplifier (23) decreases, the output voltage Vout also decreases.

Abstract: A power conversion apparatus of this invention includes a power switching device, a voltage sensor, a current sensor, and a device controller connected to the switching device, the voltage sensor, and the current sensor. The voltage sensor detects an output voltage of the switching device to output a first signal depending on the output voltage, and the current sensor detects an output current of the switching device to output a second signal depending on the output current. The device controller includes a driver connected to the switching device and a correcter connected to the driver, the voltage sensor and the current sensor. The driver outputs a third drive signal to the switching device. The correcter monitors a switching loss and a surge voltage by using the first and second signals, and corrects the third signal depending on values of the switching loss and the surge voltage.

Abstract: A digital electric power inverter comprising: a CPU, a PWM driving circuit, a PWM converting circuit, a rectifying circuit, an AC driving circuit, a DC/AC inverting circuit, a plurality of detecting circuits and an alarm circuit, the power inverter is characterized by that: the entire circuitry thereof is designed to be controlled by the CPU that can accurately control these circuits to endue the power inverter with an intact and multi-selection protecting function, thus render the parts thereof to develop their largest effects.

Abstract: A circuit for providing a polarity sensing power and signal interface. The circuit includes a rectifier circuit operably connected a two line system wherein the rectifier circuit is comprised of at least two transistors for providing the circuit with a low-impedance path to ground and providing the circuit with a polarity insensitive output. Capacitors may be operably connected to transistors in the rectifier circuit to keep the transistors turned on when a low voltage is applied to the rectifier circuit.

Abstract: The invention is designed for vehicles having two electrical power supply systems and corresponding differentiated voltage level charges and two batteries operating at a first and a second voltage level. A bidirectional voltage converter cooperates with both systems whose input and output stages are galvanically insulated and include a switch. The batteries are connected to said input and output at a first and a second voltage level so that said bidirectional converter can provide a first reduced voltage mode and a second increased voltage mode. The passive components, e.g. the magnetic components and capacitances, of said stages have been chosen to provide an identical transitional behavior in both modes when a disruption occurs in the regulating system either in the charge or the input voltage.

Abstract: In a configuration of a complex resonance type switching converter provided with a voltage resonance type converter on the primary side and a parallel resonant circuit or a series resonant circuit on the secondary side, control of voltage obtained at a secondary winding and control for constant voltage on the secondary side are achieved by providing an active clamp circuit on the secondary side. The switching frequency of the circuit is constant. Thus, products having low withstand voltage may be selected as components such as a switching device and a resonant capacitor to be provided on the secondary side of the power supply circuit. In addition, it is possible to simplify configuration for constant-voltage control.

Abstract: To display the sum of power generation in a photovoltaic power generation system having a plurality of independently-operating inverters in real time, an information display device receives information indicative of amounts of power generation respectively outputted from the plurality of inverters, calculates the sum of power generation in the plural inverters based on the received information, and displays the result of calculation.

Abstract: In order to reduce a power consumption in a standby state of a load of a switching power source by intermittently controlling an oscillation of a switching element of the switching power source when the load is in the standby state, a time period covering a time at which a voltage of an A.C. power source 10 is a peak is detected by an intermittent oscillation control circuit 12 and supplies the detected time period to a switching control circuit 13 through signal transmission circuits 14 and 15 to allow an oscillation of a switching transistor Q1 for only that period while stop the oscillation thereof for other time than that time period. Since it is possible to perform the oscillation of the switching transistor Q1 for only a charging time of a smoothing capacitor C1 provided on a primary side of a switching transformer of the switching power source, a variation of a voltage on a secondary side of the switching transformer is minimized.

Abstract: A method whereby a plurality of inverters for converting DC power outputted from a DC power supply, such as solar cells or fuel cells, to AC power are operated efficiently without being biased to particular inverters. The number of inverters to be run is determined in correspondence with at least one output value of the DC output or AC output, and the determined number of inverters are selected and made to run from among the plurality of inverters on the basis of a predetermined rule. In addition, a parallel-connected system is disclosed for enabling efficient and appropriate parallel-in operation by the use of inverters, with one of the inverters controlling the remaining inverters and effecting system interconnection protection.

Abstract: A voltage regulator is provided. The voltage regulator comprises a first voltage-controlled current regulator having a first power input and at least one additional voltage-controlled current regulator having at least one other power input. The first and the at least one additional voltage-controlled current regulators have first and second current paths, respectively, and a common output node. The voltage regulator also includes an error amplifier that is responsive to the common output node. The error amplifier further has an output. The output of the error amplifier provides a common feedback signal to the first and the at least one additional voltage-controlled current regulators so as to establish selected currents drawn by the first and the at least one other power inputs and provided to the common output node.

Abstract: A method and apparatus for controlling the providing of conditioned AC power, with the conditioned AC power being capable of being provided on a continuous basis. Unconditioned AC voltage is received by transverters. The transverters convert the unconditioned AC voltage into a transverter AC output voltage. The transverter AC output voltage is monitored by current and voltage sensors. A transverter control signal is developed in response to changes in the current and voltage sensing in comparison with a reference signal. The transverter control signal then regulates conversion of the transverter AC output voltage into the desired conditioned AC output voltage. In multi-phase AC voltage systems conditioned AC voltages for each phase are provided.

Abstract: A method is provided for compensating an output signal of an electronic device having an input end electrically connected to a feedback device and an output end electrically connected to a load. This method includes steps of (a) measuring a standard voltage V.sub.o of the load, (b) determining an input voltage V.sub.i and an input current I.sub.i of the electronic device, and (c) generating a feedback signal based on said input voltage V.sub.i. The method further includes steps of (d) determining a maximum current I.sub.max and a minimum current I.sub.min of the feedback signal passing through the feedback device, (e) defining an estimated output current I.sub.o of the electronic device based on the maximum current I.sub.max and the minimum current I.sub.min, and (f) compensating the output signal of the electronic device according to a compensating factor d determined by the standard voltage V.sub.o, the input voltage V.sub.i, the input current I.sub.i, and the estimated output current I.sub.

Abstract: The present invention relates to circuits and methods for improving the efficiency of step down switching regulators converting a high input voltage to a low output voltage. Furthermore, the present invention relates to circuits and methods to achieve such efficiency improvements while maintaining controllability during light output load conditions. In a preferred embodiment, the current mode switching regulator circuit includes a logic section, an output switch section controlled by the logic section, an oscillator for providing periodic timing signals to the logic section to turn the output switch ON, a feedback amplifier for developing an integrated error signal based on the output voltage, and a current comparator including an output, the current comparator for comparing the integrated error signal to the instantaneous value of the current in the output switch, the output of the comparator producing a signal which causes the logic section to turn the output switch OFF.

Abstract: A step-up transformer is switching controlled to cause it to generate a high voltage, the generated high voltage is rectified and smoothed to generate a DC output voltage, and the generated DC output voltage is supplied to a load. The generated DC output voltage is converted into a low voltage to detect a voltage value, and further a load current is detected. By such structure, a voltage detection circuit is not directly connected to a ground potential but is connected to a current detection circuit. Thus, even if a state of the load of an image formation apparatus varies due to an environmental condition and the like, an optimum current can be supplied to the load.

Abstract: A solar cell power source device is disclosed which optimizes the power output of the solar cell by detecting a maximum power point of the solar cell and controlling the duty cycle of a switching transistor in a switching power converter such that the output current of the solar cell follows the maximum power point. Also shown is a pulse width modulation controller which multiplies the output voltage of the solar cell by the output current of the solar cell to obtain a power detecting signal, samples the power detecting signal during two different sample periods to determine if the power output is decreasing, and modulating the pulses output to the switching transistor of the switching power converter in order to maintain the power output of the solar cell at the maximum power point.

Abstract: In a power control apparatus of a solar power generation system for converting power generated by a solar panel and supplying the converted power to a load, the output voltage and output current of the solar panel are sensed, and, under ordinary conditions, MPPT control is performed so that the solar cells will operate at a maximum output point. If the output power of the solar panel exceeds a predetermined power, a power conversion unit is controlled so as to raise the output voltage of the solar panel, thereby limiting the output power of the solar panel. As a result, excessive power is prevented from being output by the power control apparatus.

Abstract: A method and a circuit arrangement for shaping any actual a.c. voltage characteristic into any reference a.c. voltage characteristic are described, which store the excess power in voltage overshoots in the form of a current in a current storage device using power electronic switching elements, and thus they compensate for the power deficiency when there is a voltage shortfall. The power electronic switching elements are driven by a digital automatic state machine through appropriate control pulses so that there is no fixed switching rate. The preferred field of application is for active filtering of the voltage of an electric three-phase or a.c. power supply system.

Abstract: A current-mode control device for controlling an output voltage of a DC power supply including: a switching element for supplying an output voltage of the DC power supply through an on/off switching action; an output voltage detector circuit for detecting the output voltage of the DC power supply and outputting an output voltage based on the output voltage of the DC power supply; a current sense circuit for converting into a voltage a switching current flowing through the switching element during the switch-on period of the switching element to sense and output the resulting voltage; an integrating circuit for converting the switching current of the switching circuit that increases at a gradient of a straight line linear function with time during of the switch-on period of the switching element into a voltage that increases at a rate defined by a quadratic or higher-order curved line with time by integrating the switching current of the switching circuit at least once and for superimposing the resulting volta

Abstract: A flyback converter including a transformer (6) having a primary winding (4) and a switching transistor (2), arranged in series therewith; control device (14) for closing the switching transistor (2) during a primary interval and opening the switching transistor (2) during a secondary interval in response to a control signal (U.sub.c), an auxiliary winding (12) for generating a feedback signal (U.sub.FB), measurement device (20) for unidirectionally measuring the feedback signal (U.sub.FB), a comparator (16) and a logic circuit (18) for deriving from the feedback signal (U.sub.FB) a first timing signal (TM.sub.1) which is representative of the secondary interval; comparison device for comparing the unidirectionally measured feedback signal (I.sub.FB) with a reference signal (I.sub.R) during the secondary interval, and an integrator (28) for generating the control signal (U.sub.C) in response to the comparison.

Abstract: A method and apparatus for controlling the providing of conditioned AC power, with the conditioned AC power being capable of being provided on a continuous basis. Unconditioned AC voltage is received by transverters. The transverters convert the unconditioned AC voltage into a transverter AC output voltage. The transverter AC output voltage is monitored by current and voltage sensors. A transverter control signal is developed in response to changes in the current and voltage sensing in comparison with a reference signal. The transverter control signal then regulates conversion of the transverter AC output voltage into the desired conditioned AC output voltage. In multi-phase AC voltage systems conditioned AC voltages for each phase are provided.

Abstract: In order to extract maximum power from a solar cell, maximum power point tracking (MPPT) control is performed under ordinary circumstances. If the output current of the solar cell becomes too small, the operating point of the solar cell is caused to fluctuate over a range wider than that of MPPT control at a period longer than that of MPPT control and the output voltage and current of the solar cell is sampled. In a case where it is indicated by power values obtained from the sample voltage values and current values that a plurality of maximal points of power value exist, a voltage value corresponding to a power value indicative of the largest value is set as the operating point of the solar cell.

Abstract: In a method for control of an installation for transmission of high-voltage direct current in dependence on at least one stress parameter for a valve in a converter included in the installation and controlled by control equipment (CE1, CE2), a value (PDR, PDI, UMAX, TRC, TTC) of the stress parameter is continuously calculated, based on predetermined relationships (f1, f2, g1R, g2R, g1I, g2I, h1, h2) and in dependence on measured values (UN, .alpha., .gamma., ID, TO, TI, RECT/INV) of the operating parameters of the installation. At least one influencing signal (HTH, HCC, HCR) is generated in dependence on a comparison between the calculated value and at least one comparison value for the parameter, and the influencing signal is supplied to the control equipment to influence this in a direction which limits the value of the stress parameter.The member (HAS) comprises a monitoring device (PD, UA, TR, TT) for calculating the value of the stress parameter.

Abstract: A method and apparatus for controlling the providing of conditioned AC power, with the conditioned AC power being capable of being provided on a continuous basis. Unconditioned AC voltage is received by transverters. The transverters convert the unconditioned AC voltage into a transverter AC output voltage. The transverter AC output voltage is monitored by current and voltage sensors. A transverter control signal is developed in response to changes in the current and voltage sensing in comparison with a reference signal. The transverter control signal then regulates conversion of the transverter AC output voltage into the desired conditioned AC output voltage. In multi-phase AC voltage systems conditioned AC voltages for each phase are provided.

Abstract: A power control method and apparatus for extracting the maximum power from a battery power source are disclosed. Voltage signals and current signals are read while varying the operating point of a solar cell acting as the battery power source. The variation in the intensity of solar radiation that has occurred during a sampling time interval is estimated from a plurality of current signals, sampled at the same voltage, or, according to a plurality of power values, calculated from current signals and voltage signals. Based on the estimated variation in the intensity of solar radiation, the current signals or power signals are corrected. According to the corrected current signals or according to the corrected power values and the voltage values, the operating point is controlled so that the maximum output power is provided from the solar cell.

Abstract: A pulse width modulated controller controls a zero-voltage switching resonant power converter or inverter. The on time of the power switch (110) of the converter or inverter is varied by an error amplifier (280) such that the output voltage of the converter or inverter maintains proportionality to a reference voltage (290). The off time is terminated by a switch-voltage detector (320) when the voltage across the power switch (110) drops below a threshold voltage (330) due to the natural resonance of the external resonating capacitor (120) and inductors (130 and 150). In the first two embodiments of the invention, a single timing capacitor (260) is employed both for determining the on time and the off time. In two other embodiments, two timing capacitors (262 and 264) are employed for separately determining the maximum allowed off time and the variable on time.

Abstract: An electrical power conversion system that supplies the maximum available output power from a power source such as a solar array to a plurality of loads such as rechargeable batteries. The output power of the solar array peaks at an optimum current that is less than is maximum available output current. The system includes a controller and a plurality of dc-to-dc converters that charge the batteries. The controller monitors the solar array's output power and adjusts the battery charging by generating a current control signal that tracks a peak of the solar array's available output power and sets a current limit such that the combined current draw of the plurality of dc-to-dc converters is substantially equal to the solar array's optimum current at which it provides its maximum available power. The electrical power and control signals are transmitted from the power source and controller to the power converters on three bus bars, including a power bus, a control bus, and a common bus.

Abstract: A large signal, linear, digital, unity power-factor controller for controlling a power supply is disclosed. The power supply controller includes a voltage controller and a current controller. The voltage controller is a feed forward and proportional-integral type of controller. By determining the control command of the voltage controller as a function of the feed forward load power, the power term in the state equations for the voltage controller is eliminated. As such, the current controller operates in time domain in such a way that the voltage controller appears as a unit time delay to the current controller. The load is a battery incorporated within an electrically-powered vehicle. The controller operates to charge the battery. The connection between the battery and the power supply being controlled is an inductive coupling.

Abstract: A power control system for obtaining the maximum electric power from a battery power source. The system functions to vary an output voltage of the battery power source to obtain (m) power values from at least (m) voltage signals from a voltage detector and at least (m) current signals from a current detector which were sampled at desired intervals. A function is used which approximates the relations between the (m) voltage values and (m) power values. A voltage is calculated at which a power is set to a maximum value from the function and the (m) voltage and power values. The power is set at such a voltage into an output power set value and the output power of the battery power source is controlled.

Abstract: A power supply circuit arrangement for electrical equipment, such as a loudspeaker with an integral power amplifier, which can be switched between an operational mode and a standby mode in response to a detected on/off signal, provides a desirable isolation of the main supply voltage from the detector. The arrangement comprises a transformer, having a primary winding and a secondary winding, and a switched impedance device between the transformer and the power supply input. The switched impedance device is switchable between high and low impedance states in response to the detected on/off signal. A control circuit for detecting the on/off signal and switching the variable impedance states is connected in common with a main circuit of the equipment to the secondary winding of the transformer, so that their respective supply voltages are both switched, in common, by switching of the impedance device. The control circuit and variable impedance device isolate the detector from the power supply.

Abstract: An intermittent on/off regulator type DC power supply circuit having low noise and low losses includes a voltage detector at the power source side of the circuit and/or a current detector at the load side of the circuit which feeds back voltage and or current values to a central controller and intermittently cuts off the input or output of a transformer or rectifier whenever preset voltage or current levels are exceeded thereby preventing, for example, overcharging of a battery.

Abstract: A device for suppressing voltage fluctuation and higher harmonics of a power source system which supplies power to a load with large power fluctuation and large harmonic current. The device includes a self-commutated converter arranged in parallel with the load and a control circuit for controlling the self-commutated converter. The control circuit includes a compensation current variable calculation circuit for calculating a plurality of compensation current variables based on electrical quantities of the power source system and the load, a compensation gain calculation circuit for determining at least one compensation gain based on at least one of the compensation current variable, and a current instruction value calculation circuit for calculating a plurality of respective current instruction values based on the compensation gain and a plurality of the respective current compensation variables.

Abstract: A control device for a system interconnection inverter. The control device includes an active/reactive current reference generator and an active/reactive current detector for detecting an output AC current of the inverter. The control device further includes a phase detector, a frequency detector, and a voltage amplitude detector of the AC voltage of the inverter. The control device also includes a frequency reference generator and a voltage amplitude reference generator. The control device also includes a frequency correction computing circuit and a voltage amplitude correction computing circuit. The control device further includes an adder for adding the active current reference signal and the voltage amplitude correction signal to output as an active current correction reference signal, and for adding the reactive current reference signal and the frequency correction signal to output as a reactive current correction signal.

Abstract: A static energy regulator for lighting in the form of a device that is inserted between the feed and the load has a converter, connected to the load and to a controller, so that the intensity signal through it follows the form of an indication signal. Another converter, connected to the feed and to another controller, supplies an intensity signal that follows the form of another recognition signal proportional to the voltage of a condenser connected between the two converters. Thus it is possible to control the energy flux, to keep consumption at the desired value, compensate for variations of the power supply, reduce costs and lengthen the life of the load. The regulator can be applied to any charge whether or not it is linear and regardless of power factor. In application thereof to lighting it permits the reduction of the luminous flux thus overcoming the inadequacies of previous systems and effectively controlling the characteristics of the energy supplied.

Abstract: A regulated power source for supplying power to a circuit, the power source including a regulated power converter generating an output voltage for the circuit, the converter including a control terminal through which the output voltage can be regulated by feedback from the circuit; a monitoring circuit including a plurality of input terminals each of which monitors a voltage at a different location on the circuit, the monitoring circuit producing a control signal that is a function of all of the monitored voltages at the plurality of input terminals, the control signal driving the control terminal of the regulated power converter so as to regulate the output voltage to maintain the control signal at a constant value.

Abstract: A control method for a PWM converter which is connected to an AC current source via a reactor, and performs the sending and receiving of power between the AC power source and a DC power source, includes a step of separating a supplied AC current into an effective current and a reactive current and performing PWM control and a step for control so that said reactive current is larger when there is conversion of DC power into AC power, than when there is conversion of an AC power into DC power.

Abstract: A voltage estimator for a generating system having a DC link and an inverter detects the magnitudes of the voltage and current on the DC link and develops an estimate signal representing the estimated magnitude of a fundamental component of output voltage developed by the inverter from the sensed DC voltage and current magnitudes.

Abstract: An apparatus and method for current sharing among multiple power supplies is disclosed. The output current of each power supply is compared in an amplifier which produces an output signal. This signal controls a transistor used to enable or disable current flow on a SENSE line in a particular power supply. By controlling the SENSE line, the output current of each power supply is adjusted to roughly equal levels. The combined current is thereby the combination of approximately equal shared outputs of each individual power supply. The current share of each individual power supply is offset by a predetermined level to prevent a race condition in the initial power-up phase.

Abstract: A load test system for testing an engine/generator (12) and battery set (14) of a backup power system by simulating a load with desired linear, non-linear and/or reactive load characteristics. The load test system also recharges the battery set (14) after testing. Battery imbalance circuit (40) is connected to battery set (14) to determine whether bad cells are present therein. Controller (110) uses signals from current monitors (24, 125) to monitor the current, and isolation transformer (47) to monitor the AC line voltage. The controller (110) simulates a desired load by causing a rectifier (200) comprising thyristors to turn on at a selected point on the AC waveform and/or by causing a load bank (300) to draw a predetermined load current when a predetermined load voltage is present. Capacitive load circuit (28) selectively places a large capacitance across the DC bus (203). When the capacitance is present, surge current at thyristor turn-on simulates a non-linear or reactive load.

Abstract: Voltage-control and current-limiting negative feedback loops are disclosed that cooperate with an adjustable voltage regulator to provide a constant-amplitude and current-limited D.C. voltage. The regulator and voltage-controlling and current-limiting feedback loops are constituted by low-cost circuit elements that cooperate to provide high-precision voltage and current regulation in a manner that is free from manual adjustment. The circuit of the invention is particularly adapted to charging lead-acid batteries.

Abstract: A circuit wherein a current sensing device is incorporated in an AC input line. An AC output is taken from the output of the current sensing device and from an other AC input line. Circuitry including a capacitor coupled bi-directional switching regulator and an energy storing capacitor adds current to or subtracts current from the instantaneous output load current. The arrangement is such that the AC output is equal to the AC input with no regulation effect. Substantially one hundred percent efficiency results when very little power factor correction is required.

Abstract: A power converter circuit requiting the periodic reset of a core of the power transformer includes a control circuit operative to alter a response of the converters voltage regulation feedback control to limit and/or control the power switch duty cycle to regulate a voltage of the reset capacitor whenever the reset capacitor sustains a voltage above a preset threshold.

Abstract: A circuit wherein a current sensing device is incorporated in an AC input line. An AC output is taken from the output of said current sensing device, and from an other AC input line. Circuitry including a bi-directional bridge rectifier followed by a bi-directional switching regulator and an energy storage capacitor adds current to or subtracts current from the instantaneous output load current. The arrangement is such that the AC output is equal to the AC input with no regulation effect. Substantially one hundred percent efficiency results when very little power factor correction is required.

Abstract: An electric power supply system used in electric trains or electric buses is equipped with a device for removing ripples of low frequencies which cause flickering in a lighting system on the train or bus. The system includes an inverter for inverting DC power to AC power, a low pass filter for passing components of the AC power having low frequencies, amplitude detecting means for detecting an amplitude of an output of the filter, error detecting means for detecting any deviation of the amplitude from a reference signal, and a control system for detecting and removing flickering components from an error signal generated by the error detecting means. The control system includes a flickering component passing device for passing only flickering components contained in an output of the filter, a phase compensating device for compensating a phase lag of the flickering components, and a gain compensating device for compensating a gain of the flickering components.

Abstract: A current supply has a first voltage summing circuit with two inputs, one of which receives a signal that indicates a desired current level to be produced. A current source produces a current level at an output in response to a control signal received from the first voltage summing circuit. The current source output is coupled to a center tap of the primary winding of a transformer that has a capacitor connected across the end terminals of its primary winding. Separate transistors connect ends of the primary winding to a common node and a resistor couples the node to circuit ground. A sensor produces a voltage e.sub.i that is proportional to a magnitude of the current flowing through said capacitor. A second voltage summing circuit produces an output voltage e.sub.t equivalent to the sum of voltage e.sub.i and the voltage across the resistor and the output voltage e.sub.t is applied to the other input of said first voltage summing circuit.

Abstract: A voltage regulator generates an output voltage between an output line and an output reference voltage from an input voltage between an input line and an input reference voltage. The voltage regulator combines a self excited series resonant oscillator and a switching regulator control circuit. The self excited series resonant oscillator includes an oscillator circuit which produces an oscillating signal. The oscillating signal is rectified to produce a rectified signal. The rectified signal is filtered to produce the output voltage on the output line. The switching regulator control circuit switches the self excited series resonant oscillator on and off at a duty cycle which maintains the output voltage on the output line at a predetermined value.

Abstract: A control system for controlling an inverter having a connector for connecting the output of the inverter to a load wherein a temperature sensing arrangement senses the temperature of the connector and a controller responds to the temperature of the connector for controlling the inverter in order to control the inverter output.

Abstract: To maintain a defined three-phase voltage system at the output terminals of a transformer device TE, for example, a transformer in a delta/wye connection where the primary-side neutral point is unconnected, even when an asymmetrical load is connected to it and to the secondary-side neutral point, single-phase transformers are used, whose primary windings are supplied with voltage by a pulse-width modulated, three-phase invertor in a bridge connection. Through the use of voltage regulators, the actual values of the secondary-side line voltages form the control voltages for each bridge-arm pair. The closed-loop control circuits of the three phase voltages are broken down in accordance with the structure of the transformer device by means of a break-down element. The setpoint values can be calibrated to a synchronizing voltage, and/or a current control for the conductor currents is superposed on the voltage regulators.

Abstract: A series resonant power converter in which a resonant copacitor is commonly used in a series resonant circuit and a parallel resonant circuit, whereby a capacitance of the resonant capacitor can be considerably decreased as compared with that of a tank circuit according to a prior art, so that an energy handled by the resonant capacitor can be decreased, which results in decreasing a size of the resonant circuit and also decreasing a power loss. The converter includes means for detecting and computing a voltage applied across a main switch means in its OFF-state and a control circuit for driving the main switch means to its ON-state when the detected and computed value of the voltage drops to a minimum voltage required to sustain oscillation of the series resonant circuit.

Abstract: A power supply including a resonant converter is provided with current shunt. The current shunt automatically shunts a portion of current flowing in the resonant converter at light loading of the power supply such that output current flowing in an output circuit connected to the power supply would be reduced toward zero as the operating frequency of the converter moves to a predetermined frequency.