Abstract: A discharge lamp driving device capable of detecting a lamp life end reliably in a high or low temperature environment for circuit protection, yet preventing the occurrence of the cataphoresis phenomenon. Impedance elements Z1 and Z1 are inserted respectively between one filament ends of individual discharge lamps La1 and La2 and a node (the ground) having no high frequency amplitude in order to detect a difference between AC components of individual lamp voltages VLa1 and VLa2 in closed loops of the discharge lamps La1 and La2 and the impedance elements Z1 and Z1 in order to judge whether or not the depletion of the emitter occurs. Thus, it is possible to reliably judge the presence of abnormality even when the amplitudes of the lamp voltages VLa1 and VLa2 varies in a range of low to high temperature.

Abstract: The present invention provides a simple circuit for a DC power supply. The power supply circuit of the present invention includes a transformer in combination with a switching power supply circuit. The transformer includes a primary winding to which a wide range of AC input voltages is applied and a secondary winding for supplying the resultant AC voltage range as an input voltage to the switching power supply circuit. The switching power supply circuit further includes an input terminal having the input voltage applied thereto by the secondary winding and further having an output terminal from which a DC power supply output is generated. The transformer can be selected from a group of transformers consisting of step-down, step-up and repeater transformers. The switching power supply circuit may be selected from any convention switching power supply circuit including step-up, step, down and inverter converters, and combinations thereof, or even linear configurations.

Abstract: A method of controlling a parallel operation of two inverter power generation apparatuses wherein an unbalance of outputs from the two inverter power generation apparatuses is cancelled by judging that the outputs of the two inverter power generation apparatuses have the collapse of the balance between them when a DC power supply voltage obtained from a DC power supply section exceeds a judgment value set at a value equal to or more than a non-load output voltage of the DC power supply section and allowing an overload operation of the inverter power generation apparatus of higher output voltage among the two inverter power generation apparatuses so as to lower the output voltage of the corresponding inverter power generation apparatus.

Abstract: The present invention provides a visual messaging device for use with a high-speed network and an electrical supply system for the visual messaging device. The visual messaging device includes a network interface circuit that receives the message data from a network and arranges it in memory unit in usable form (packets) for use by a processor at the high network speed. The electrical supply system utilized with the visual messaging device comprises, in part, a power source, located in a remote location relative to a low voltage, high current device, which provides for the transmission of electrical power to the low voltage, high current device, such as a visual display unit, via relatively thin wiring or cabling passing through an enclosure, such as a plenum air space, without the need of placing the wiring or cabling in a conduit.

Abstract: To minimize the energy required for operation of a rail vehicle, in a drive system that has an intermediate circuit converter 1 and a three-phase motor 7 fed by it, the intermediate circuit voltage in the intermediate circuit 12 and/or the magnetic flux in the drive motor 7 are optimized to correspond to the actual operating requirements, including, if necessary, the energy expenditure for the auxiliaries 9 that are provided to cool the components.

Abstract: The present invention provides a control algorithm which instantaneously detects magnetic pole positions in the inside of a motor including polarities of the motor. A controller 1 applies a minute voltage change vhd to a voltage command on a dc axis which constitutes an estimation magnetic pole axis of the motor 3, detects electric currents Idc, Iqc of a motor 3 and discriminates the polarities of the magnetic pole axes by making use of the difference between a cycle in which ripple components of the electric currents Idc, Iqc become positive and a cycle in which the ripple components become negative or the difference between positive-side and negative-side current change rates. Further, the minute voltage change vhd with respect to the above-mentioned voltage command is generated on both of the dc axis and the qc axis rectangular thereto, and the magnetic pole positions of the motor are directly estimated based on the current ripple components on the respective axes.

Abstract: A control system (20) for a power converter (22) designed to convert DC power from a source (30) such as a battery, flywheel or fuel cell into AC power. The control system includes an impedance current regulator (106) for providing an impedance current signal to a summing unit (110) where it may be combined with real and reactive current command signals provided from respective sources (62, 64). The resultant current signal provided by the summing unit is provided to a voltage correction unit (112) that uses the resultant current signal in developing a correction voltage signal provided to the power converter. The correction voltage signal contains information used by the power converter in adjusting the real and reactive currents in its output AC power based on the ability of the AC power network to accept changes in current.

Abstract: The invention in the simplest form is a power conditioning and inverting system for improved and efficient power generation. In particular, the present invention is a modulated dc link scheme that dramatically reduces the switching frequency ripple across the PWM output filter inductor and provides cost, size, and weight reductions, as well as efficiency enhancements. In a preferred embodiment of the present invention, the DC-DC converter control takes a feedback signal proportional to the inverter output voltage. This feedback is “summed” into the primary DC-DC volts command thereby causing the dc bus/link voltage to vary at a multiple of the output fundamental frequency causing the DC link to become a signal at a fundamental frequency voltage with a dc offset. The tooth modulator DC supply tracks the AC output voltage, reducing the difference between the applied DC volts and the AC output volts, thereby reducing inductor core losses.

Abstract: A power generation apparatus includes a permanent-magnet AC generator, a first converter for converting AC power into DC power, and a second converter for converting the DC power produced by the first converter into AC power. The first converter includes a unit for controlling active power and a unit for controlling reactive power and the second converter includes a unit for controlling a voltage of a DC system and reactive power or AC voltage of a power system.

Abstract: A hybrid power generation system for neutralizing contaminated air while generating power is disclosed. The system includes a generator, compressor, combustor, turbine, and recuperator defining an air/gas flow path. The system includes a fuel cell module located along the air/gas fuel path, and a power controller. The power controller converts AC power generated by the generator to DC power on a DC bus for providing power to a load. The fuel cell module neutralizes air contaminates in the incoming air while generating power. The power controller regulates the air flow in the air/gas flow path to control the efficiency of the fuel cell module, independent of the DC power on the DC bus.

Abstract: A method for distributing power in a electronic system includes transmitting power in a high frequency alternating current (AC) domain from a system power supply of the computer system to a high frequency AC voltage regulator module.

Abstract: Method and apparatus are disclosed for providing a constant voltage, high frequency sinusoidal output across a varying load, using either a single or multiple switch topology operating at constant frequency while maintaining high efficiency over the entire load range. This embodiment is especially suited to applications which require the sinusoidal voltage be held very close to a desired value in the presence of rapid changes in the conductance of the load, even in the sub-microsecond time domain as is common in computer applications and the like and in powering electronics equipment, especially a distributed system and especially a system wherein low voltage at high current is required.

Abstract: This invention relates to a current control circuit for use as a load circuit for a lamp, such as a gas discharge lamp. The current control circuit comprises two or more capacitors connected in series with each other and with said lamp.

Abstract: An electric power conversion apparatus includes a noise reduction device for reducing the common mode noise and the normal mode noise caused by on/off of the switching devices of an electric power conversion apparatus for driving an AC motor. Since the noise-compensation-current supply circuit of the noise reduction device uses devices with a lower breakdown voltage, the operating speed of the noise-compensation-current supply circuit is higher than the operating speed of the conventional noise-compensation-current supply circuit which uses devices with a higher breakdown voltage equivalent to the DC voltage of the electric power conversion apparatus.

Abstract: The invention relates to a converter for converting a DC voltage UBat into an output direct voltage Uout, in particular in TV or computer screens. The converter comprises a full-bridge circuit 7 for chopping the DC voltage UBar into an AC voltage U˜ on its output and a switching circuit 3 for converting the AC voltage U˜ into the output direct voltage Uout of the converter. The converter further comprises a control circuit 5 for generating control signals to drive controllable switching elements S1 . . . S4 in the full-bridge circuit. The problem for the invention is to further develop such a converter so that the output voltage Uout generated by it remains stable even during a switching of the full-bridge circuit between two operating modes. This problem is solved by the invention in that the control circuit 5 only carries out this switching during a dead time interval ttot, during which at least one of the switching elements S1 . . . S4 is switched off.

Abstract: In a power conversion device according to the present invention, an AC power source voltage signal Vac which is the instantaneous value of AC power source 1 detected by a power source voltage detection circuit comprising a transformer 5, rectifier 6 and A/D converter 7 is averaged by an averaging circuit 9 and an average AC power source voltage signal Vave is output. This average AC power source voltage signal Vave and AC power source voltage signal Vac are compared in comparator 8 and, if their deviation is more than a prescribed value, a power source voltage drop detection signal PSF_S is output. Spurious detection of power source voltage drop resulting from the effect of power source fluctuations can thereby be prevented.

Abstract: A circuit for receiving electrical power from a switched source such as a solid state relay, and providing power to a semiconductor light source. A rectifier circuit and an interference filter are connected in series between input connections which are connected to the switched source, and a converter which provides the required voltage and current combination for the light source. To prevent improper operation of the switched source, such as oscillation, the portion of the circuit between the input terminals and the rectifier circuit is free from capacitive elements. Preferably the interference filter is connected between the rectifier and the converter. The light source may be used as a signal light, and the circuit may be incorporated in the housing of the signal light.

Abstract: A power line separator, comprising an input for connecting to a source of AC line voltage, an output for connecting to at least one user appliance intended for operation with a source of AC power having similar characteristics to the AC line voltage, and a front-end power factor correction unit coupled between the input and the output for producing from the AC line voltage a sinusoidal voltage that causes no distortion of the AC line voltage, while providing power to none-linear load, or loads with imaginary portion (reactive/inductive).

Abstract: An ac-to-ac power converter includes a source-side inverter that is operated in current mode and a drive side inverter that is operated in commutation mode. The source side inverter performs current regulation during a first portion of each modulating cycle and space vector modulation during a second portion of each modulating cycle.

Abstract: A power regulator for use with an AC power source includes a voltage converter having a first input and a second input. The first input is connected with the AC power source and receives AC current therefrom. The second input is connected to a controller and receives a control signal therefrom. The voltage converter generates a substantially sinusoidal regulator output signal, the amplitude of which is responsive to the control signal. The power regulator also includes a controller having a first input and a second input. The first input receives the regulator output signal and the second input receives a set point signal. The set point signal determines the amplitude of a substantially sinusoidal reference signal which is substantially in-phase with the regulator output signal. The controller generates the control signal indicative of the instantaneous difference between the regulator output signal and the amplitude of the substantially sinusoidal reference signal.

Abstract: A lamp ballast circuit which provides a magnetizing inductance to a lamp ballast circuit transformer. A DC voltage and current supply source energize a pair of transistors which provide an AC voltage and current. The transformer includes a primary winding that receives the AC voltage and current. At least one lamp is coupled to the transformer secondary winding via a capacitor. The circuit has an optimal magnetizing inductance such that the transformer input voltage and current are substantially in phase with each other, thereby substantially reducing or eliminating the reactive power transferred through the output transformer. In a preferred embodiment, the magnetizing inductance, L102, is given as: L&khgr;=[1−(&ohgr;sC1R1)2]/n2&ohgr;s2C1, wherein &ohgr;s is an operating frequency, C1 is the capacitance of the capacitor, R1 is the resistance of the at least one lamp, and n is the secondary-to-primary side turns ratio of the transformer.

Abstract: Methods and apparatus for supplying power for use in metering electrical energy over a wide range of voltages with a single meter are disclosed. The wide ranging meter includes a processing unit for processing divided input voltage and a current component in order to determine electrical energy metering values. The processing unit is operable in response to supply voltages. A power supply, connected to receive the undivided voltage component, generates the supply voltages over the wide dynamic range. It is especially preferred for the power supply to include a transformer having first, second and third windings, wherein the undivided voltage component is provided to the first winding and wherein the second winding defines the output of the power supply. A switching member is connected to the first winding for permitting and preventing the flow of current in response to a control signal. A control member generates the control signal in response to the output of the power supply.

Abstract: A method and apparatus for conducting regenerative braking for a motor load is disclosed wherein the load is driven by a plurality of power cells on each phase-line to the load, the plurality of power inverters comprising at least one single phase power inverter and at least one 3-phase inverter wherein the 3-phase inverter is connected across 3-phase lines. First, it is detected when the motor load is regenerating a motor load voltage. Then, each single phase inverter in each phase line is shorted out after detecting the motor load regeneration. The motor load voltage is then supplied to the 3-phase inverter. Finally, the load motor voltage is lowered by conducting regenerative braking through the 3-phase inverter.

Abstract: A method and an apparatus for improving the voltage quality of a secondary power supply unit uses a compensation device with a pulse-controlled power converter which is connected serially to a transmission line through the use of a coupling transformer. Positive and negative phase-sequence system deviations are determined and a basic transmission ratio space-vector is generated from them. Control signals for a pulse-controlled power converter are generated from the basic transmission ratio space-vector through the use of the link voltage of the pulse-controlled power converter. As a result, a compensator voltage is connected serially into the transmission line. A power system voltage of an ideal power supply system is thus generated for a secondary power supply unit from a distorted power system voltage.

Abstract: An excitation apparatus for a generator includes an AC/AC inverter having a voltage holding function and connected to an output line of an AC generator. The apparatus includes an AC/DC converter, a capacitor connected to an output of the AC/DC converter, and a DC/AC converter connected to the capacitor and excites a field winding of the generator with an AC/DC converter controllable with a current and connected to the output of the AC/AC inverter. Even when a voltage of the output line is lowered due to a failure in a system, since energy stored in the capacitor is discharged and the voltage is maintained for the time being, the excitation current of the generator can be kept at a sufficiently high value.

Abstract: The invention relates to a circuit arrangement for operating a semiconductor light source, comprising

Abstract: An inverter apparatus which is capable of easily structuring a controlling program for controlling the inverter apparatus to cope with various specifications. The inverter apparatus is comprised of a control section including a CPU 1 serving as a computing means for controlling a converter unit 31 and an inverter unit 33, a memory 2, a memory 3 serving as a first storage unit for storing an inverter-controlling basic program, a parameter storage unit 4 for storing parameters, and an AP S/W storage unit 5 serving as a second storage unit for storing a plurality of inverter-controlling application programs, and a display device 6 for such as a parameter unit and having a display portion and an input portion. An inverter-controlling application program is transferred from outside the inverter apparatus to the AP S/W storage unit 5 through a telecommunication means.

Abstract: A voltage amplitude adjuster including semiconductor switches for power conversion, an AC chopper for converting an input AC voltage to an AC voltage of the same phase and different amplitude relative to the input AC voltage, and a smoothing AC filter for providing a clear signal to a primary winding of a transformer. Further, by providing a wattmeter, the saved power can be displayed.

Abstract: A switching power converter capable of operation in either Nonconversion, Stepdown, or Stepup Mode. Included is a parallel circuit of three serial connections of a first, a second and a third pair of switches. The junction between the first pair of switches is connected to an a.c. input terminal via an inductor, the junction between the second switch pair grounded, and the junction between the third switch pair connected to an a.c. output terminal via another inductor. The first and third switch pairs are driven at the frequency (e.g. 50 Hz) of an a.c. input voltage, and the second switch pair at a higher frequency (e.g. 20 kHz), in Nonconversion Mode; the first switch pair at the low frequency, and the second and third switch pairs at the high frequency, in Stepdown Mode; and the first and second switch pairs at the high frequency, and the third switch pair at low frequency, in Stepup Mode. The second switch pair is invariably driven at the high frequency.

Abstract: Method and apparatus are disclosed for providing a constant voltage, high frequency sinusoidal output across a varying load, using either a single or multiple switch topology operating at constant frequency while maintaining high efficiency over the entire load range. This embodiment is especially suited to applications which require the sinusoidal voltage be held very close to a desired value in the presence of rapid changes in the conductance of the load, even in the sub-microsecond time domain as is common in computer applications and the like and in powering electronics equipment, especially a distributed system and especially a system wherein low voltage at high current is required.

Abstract: A switching power converter capable of operation in either Nonconversion, Stepdown, or Stepup Mode. Included is a parallel circuit of three serial connections of a first, a second and a third pair of switches. The junction between the first pair of switches is connected to an a.c. input terminal via an inductor, the junction between the second switch pair grounded, and the junction between the third switch pair connected to an a.c. output terminal via another inductor. The first and third switch pairs are driven at the frequency (e.g. 50 Hz) of an a.c. input voltage, and the second switch pair at a higher frequency (e.g. 20 kHz), in Nonconversion Mode; the first switch pair at the low frequency, and the second and third switch pairs at the high frequency, in Stepdown Mode; and the first and second switch pairs at the high frequency, and the third switch pair at low frequency, in Stepup Mode. The second switch pair is invariably driven at the high frequency.

Abstract: A power supply apparatus includes an AC input port, an output port, and a bypass circuit that couples the AC input port to the output port. An AC/DC converter circuit, e.g., a rectifier circuit, produces a DC voltage from an AC input voltage at the AC input port. A DC/AC converter circuit, e.g., a current mode controlled inverter, controls current transfer between the output port and the AC/DC converter circuit responsive to a control input such that respective first and second component currents of a current delivered to a load coupled to the output port pass via respective ones of the bypass circuit and the DC/AC converter circuit. The DC/AC converter circuit may be operated such that current passing through the bypass circuit is constrained to be substantially in phase with the AC input voltage.

Abstract: A converter circuit arrangement having a DC intermediate circuit (3) includes a transformer (8) having at least two windings (9 and 10). This transformer (8) is connected in the intermediate circuit (3) such that the undesirable, unbalanced current components lead to magnetization of the transformer core and are thus reduced. A grounded LC filter (Lf, Cf) is connected upstream of the load (6) and produces a sinusoidal voltage across the load (6). In consequence, the circuit can be used with any desired rotating-field machines, and thus also for retrofitting existing systems.

Abstract: A mains power supply unit for the purpose of supplying consumers that are connected directly or by way of a voltage system converter to a direct voltage branch of a mains power supply unit comprises a buffer capacitor (C) that can be charged from the mains supply and that still supplies the direct voltage branch for a predetermined minimum period of time in the event of a failure or interruption in the mains supply. In such an event, the buffer capacitor (C) can be charged by way of a dedicated charging circuit (3) to a voltage (U2), which, regardless of the voltage fluctuations in the direct voltage branch, is substantially constant and corresponds in a substantial manner to the upper limit value of the direct voltage (U1) to which limit value the mains power supply unit is dimensioned. The buffer capacitor can be connected onto the direct voltage branch by way of a controlled switch (S) in the event of undervoltage in the mains supply or in the direct voltage branch.

Abstract: A control system is provided for positioning between a power source, such as a distributed generator, and a utility or utility grid to control the injection of dc current and even harmonics into the utility or utility grid. In one embodiment, the control system is particularly suited for grid-tied operation and includes a power converter for acting as an ac current source by converting power received from the power source to ac current for transmittal to the utility. The control system further includes a voltage transformer between the power converter and the utility connection to block dc current and isolate the power source from the utility. A feedback control loop is included in the control system to measure, with a pair of current transformers, dc current and even harmonics in the current flowing into (power converter side) and out (utility side) of the voltage transformer.

Abstract: In the present invention, a Q-phase motor, which electronically switches current paths to plural-phase windings, comprises waveform shaping signal producing device for producing Q-phase waveform shaping signals having a conduction width larger than an electric angle of 360/Q degrees and superimposed signal producing device for superimposing signals to the waveform shaping signals. The superimposed signal producing device comprises superimposed timing producing device for producing superimposed timing signals which are output in a period shorter than a conduction period of the waveform shaping signals in a conduction period of the waveform shaping signals, synchronous rectifying control device for controlling the timing for synchronous rectification, and superimposed signal composing device for composing the signals output from the synchronous rectifying control device with the superimposed timing signals.

Abstract: A noise attenuation circuit is disclosed for use in a motor drive system. The motor drive system includes a pulse width modulated inverter providing three phase power output on three phase conductors for driving a motor. The noise attenuation circuit includes a common mode transformer including a common mode choke having a core, with first, second and third choke windings on the core, each connected in series with one of the three phase conductors, and a fourth winding on the core. A three phase iron core transformer creates a neutral point representing common mode voltage. The iron core transformer has three primary windings connected in a wye configuration. A capacitor circuit is connected between the iron core transformer and the three phase conductors to prevent saturation of the iron core transformer during pulsed DC operating conditions. The fourth winding is connected between the neutral point and the DC bus and develops a common mode voltage that is equal and opposite to that existing in the system.

Abstract: A transformer outputs different (high or low) secondary voltages. A switch outputs high or low secondary voltage according to a mode signal. An electric power converter including a rectifying circuit and a switching circuit either charges a smoothing capacitor with an output of the switch or discharges the smoothing capacitor to supply a regenerative current toward the transformer with a power fact improved. An phase signal generation circuit generates PWM or PAM phase signals in accordance with the mode signal. An inverter circuit generates driving signals supplied to the motor in response to the phase signals from power from the smoothing capacitor. A mode determining circuit determines one of modes to generate the mode signal in accordance with a speed command signal and acceleration/deceleration which is indicated by the rotating speed signal and the rotating speed command signal.

Abstract: An ON-LINE uninterrupted power supply (UPS) of this invention serving as a long term high quality power supply for web, telecommunication, security system, etc is characterized in detecting a ring signal from far end for ON/OFF control of an output power and in permitting omni-range input civil power to avoid any unstable output power.

Abstract: A low cost voltage disturbance mitigation system is capable of providing continuous power to a load despite short interruptions or sag disturbances of the utility power. The interruption and sag mitigation system makes use of a combination of unique thermal and electrical properties of magnetic components, power semiconductor devices, and high-discharge-rate energy storage devices. It also facilitates a modular solution that can be easily and economically scaled up or down for use over a wide range of voltage and power levels, e.g., 480 V to 36 kV and 500 kVA to 10,000 kVA.

Abstract: A power converter for providing high frequency current to a load such as a fluorescent lamp. A rectifier circuit provides DC power to a half-bridge inverter whose output is connected to one end of a resonant load circuit. One load connection is at the other end of the load circuit, and is connected to one AC-side terminal of the rectifier circuit to provide current feedback. A voltage feedback capacitor is connected between the other AC-side rectifier circuit terminal and the other load connection. The two feedback paths contribute equivalent components to charging current for a bulk capacitor for the DC power to the inverter. Excellent fluorescent lamp ballast performance is obtained with constant inverter frequency, and with either full bridge or voltage doubler embodiments.

Abstract: In a method for open-loop and closed-loop control of an electrical drive, which comprises an asynchronous motor (18) which is supplied by a DC-AC invertor (14) with a downstream sine-wave output filter (15) with an AC voltage at a predetermined circular frequency (.omega.), stable operation with a good control response and reliable damping of natural filter oscillations is achieved in that the voltage at the output of the sine-wave output filter (15) is measured, in that the measured filter voltage is assigned a complex filter voltage vector (E) in a complex reference system rotating at the circular frequency (.omega.), and in that the DC-AC invertor (14) is actuated in such a manner that the complex filter voltage vector (E) corresponds to a predetermined required voltage vector (E*).

Abstract: A plant for transmitting electric power comprises at least one VSC-converter (1). It comprises also at least one DC/DC-converter (33, 34) having two current valves connected in series and an inductance connected to a midpoint therebetween. The DC/DC-converter is through said inductance connected to a first of the poles of the direct voltage side of the converter and through a first output terminal connected to one of the current valves to the second of the poles so as to obtain an unbalanced step-up-transformation of the direct voltage between the two poles while obtaining a potential having a higher value on the second output terminal (27) of the DC/DC-converter connected to the second current valve than on said first output terminal (28).

Abstract: An electronic interface couples a combination of generation and storage devices with a power grid and/or a load. The interface comprises a DC bus; a DC storage device coupled to the DC bus; a first DC-to-AC inverter (N1) having a DC port operatively coupled to the DC bus, and an AC port; a second DC-to-AC inverter (N2) having a DC port operatively coupled to the DC bus, and an AC port; a switch (S4) for electrically coupling the AC port of the second DC-to-AC inverter to a first generator or an AC storage device; a first rectifier (D1) for coupling an AC output of the first generator to the DC bus; and a second rectifier (D2) for coupling an AC output of the AC storage device to the DC bus.

Abstract: Systems and methods for producing standby uninterruptible power for an AC load rectify an AC utility input voltage to produce a rectified voltage and activate a DC battery voltage in response to a change in the AC utility input voltage to thereby produce a standby DC voltage. The rectified voltage and the standby DC voltage are connected to an AC load that includes input rectification to thereby produce standby uninterruptible power without the need for costly, bulky, and/or unreliable inverters or converters. Seamless transfer of power may be provided to support the AC load upon failure of the AC utility input voltage and upon restoration of the AC utility input voltage. The AC utility input voltage is preferably rectified by a diode rectifier, most preferably a full-wave diode rectifier including at least four diodes, to produce the rectified voltage.

Abstract: A low cost, small size, light weight, and highly effective system and method for providing dynamic power line voltage sag correction is provided. A dynamic voltage sag corrector includes a static bypass switch and a regulator/storage module connected together in parallel between input terminals and output terminals. Under normal operating conditions, the static bypass switch is closed, and a normal line voltage level is provided directly from the input terminals to the output terminals via the static bypass switch. When a voltage sag condition is indicated, the static bypass switch is opened, and the regulator/storage module is controlled to provide a near normal output voltage signal to the output terminals. The regulator/storage module includes a power conversion circuit which is controlled to provide the desired output voltage signal by adding a voltage level on storage capacitors to the available input line voltage signal.

Abstract: An expedient and simplified uninterrupted power-supplying apparatus is provided. Such apparatus includes a power-storing device for storing an electric signal in a first instance and releasing the electric signal in a second instance, an AC/DC converting device for converting an AC signal provided by the power source into a DC signal, a DC/DC converting device for receiving the DC signal, and generating the uninterrupted power and storing the electric signal in the power-storing device in response to a voltage thereof in the first instance, and receiving the released electric signal and generating the uninterrupted power in the second instance, and a controlling device for controlling the DC/DC converting device to store the electric signal in the power-storing device and making the AC/DC converting device vary the DC signal in response to the voltage of the power-storing device. The invention also discloses a method for supplying an uninterrupted power.

Abstract: A bipolar converter station for conversion between alternating current and high-voltage direct current comprises a first and a second active filter (AF11, AF12), each with its own piece of control equipment (CE11, CE12). The filters are intended for reduction of harmonics in a dc link, connected to the converter station, with a first and a second pole line (PC1, PC2), and each filter generates, in dependence on a sum of harmonic currents in the respective pole line, an influencing quantity (IF11, IF12) and supplies this to the dc link. The control equipment comprises frequency-selecting means (BP, CTR) which influence the frequency content of the respective influencing quantity to lie substantially within one of a first and a second of at least two predetermined, mutually non-overlapping frequency bands (FR1, FR2).

Abstract: A circuit having a full bridge configuration with a single actively biased switching element. In one embodiment, the circuit is a ballast circuit having a full bridge inverter with one switching element. The bridge includes a diode coupled to the switching element such that the diode and the switching element are coupled between positive and negative rails of the inverter. The bridge further includes first and second capacitors coupled end to end across the positive and negative rails. The ballast circuit can be coupled to a rectifier/boost circuit having a boost inductor coupled to the inverter circuit.

Abstract: A tridirectional inverter is disclosed which converts power from the single source into two different widely types of power outputs. This conversion s done by utilizing a magnetic element, i.e., a transformer, alternatively as a filter and as a voltage changing transformer. The function that the magnetic element provides is accomplished by selecting the frequency of the signal that is applied to the magnetic element.