Abstract: An apparatus for reactive power compensation in an ac medium voltage power network. The apparatus includes a common connection; a first branch including a first switch, and a first capacitor; and a second branch including a second switch and a second capacitor.

Abstract: An apparatus has a green compact electrode including a material of a coating formed on a workpiece by a discharge, a power source for supplying a first voltage, a voltage detector for detecting a voltage between the workpiece and the electrode, and a pulse current generator for generating and outputting a pulse current from the first voltage, and for cutting off the output when a predetermined period of time has passed after the voltage is detected to be less than a detection voltage. The pulse current is supplied between the workpiece and the electrode, and the detection voltage is less than the first voltage by 5% to 20% of the first voltage.

Abstract: An auxiliary power supply equipment for a high voltage installation includes a power source at ground potential, a load circuit at high potential, and a transmission link for coupling the power source to the load circuit. The power source includes a high frequency voltage generator, and the transmission link comprises a first and a second current path. Each path is closed by capacitive coupling to provide insulation between the ground potential and the high potential, and each current path has a reactive compensation means for series compensation of reactive power generated by the capacitive coupling.

Abstract: A solid-state high-voltage pulse generator based on a three-phase chopper capacitance charger is described. In a first phase, an intermediate capacitor is resonance-charged via a diode. In a second phase, the intermediate capacitor is discharged to the load through one or more solid-state switches. In a third phase, the energy remaining in the intermediate capacitor is returned to a power-supply filter capacitor. In one embodiment, the three-phase chopper includes an intermediate capacitor that is charged by first and fourth branches of a bridge and discharged by second and third branches of a bridge. In one embodiment, each branch of the bridge includes a diode in series with an inductor. In one embodiment, a composite solid-state switch connects the intermediate capacitor to a primary winding of an output transformer such that the intermediate capacitor discharges through the primary winding. In one embodiment, a secondary winding of the output transformer is provided to an output load.

Abstract: A control system (12) for a power supply (14), such as a high voltage power supply, includes a control circuit (16) and a feedback circuit (18, 28, 30). The feedback circuit (18, 28, 30) is configured to produce a feedback signal indicative of the voltage of the power supply output. The control circuit (16) is configured to control the power supply (14) based on the feedback signal and a predetermined voltage value to maintain the output of the power supply (14) at about the predetermined voltage value. A portion of the feedback circuit (18, 28, 30) may be included in an isolation shield (88) to improve the accuracy of the feedback signal.

Abstract: A transmitter for a line locator system that controls the electrical current, voltage or power applied to the target line is disclosed. Control of the electrical output of the transmitter can be achieved passively or by means of a feedback control system. A transmitter connected directly to a line can include an operator control and monitoring of current being supplied to a line to be located. Some transmitters include a current regulating circuit that controls current supplied to a line. In some transmitters, feedback controllers and feedback loops are used to regulate output current, voltage or power. Some control loops are based on monitoring currents in circuits; some control loops monitor power output from an inductive mode transmitter antenna. An inductively coupled transmitter with power output control is also disclosed.

Abstract: An apparatus has a green compact electrode including a material of a coating formed on a workpiece by a discharge, a power source for supplying a first voltage, a voltage detector for detecting a voltage between the workpiece and the electrode, and a pulse current generator for generating and outputting a pulse current from the first voltage, and for cutting off the output when a predetermined period of time has passed after the voltage is detected to be less than a detection voltage. The pulse current is supplied between the workpiece and the electrode, and the detection voltage is less than the first voltage by 5% to 20% of the first voltage.

Abstract: EMI noise in a system using a power converter with switching control is reduced in a simple configuration. The power converter 3 includes a converter 31, a smoothing capacitor 32, and an inverter 33, and receives the power from an AC power supply 1 via an AC reactor 2 and converts it into a power of an optional frequency and voltage to supply to a motor 4. Damping impedance elements 6, 7, 8 are inserted between the frame of the motor 4 and the ground 5, between the cooling fin 34 of the power converter 3 and the ground 5, and between the AC reactor 2 and the ground 5, respectively. Further, paths between the AC reactor 2 and ground 5, between the power converter 3 and ground 5, and between the motor 4 and ground 5 are insulated except that the damping impedance elements 6, 7, 8 are inserted.

Abstract: A device for control of a compensator connected to a polyphase electric transmission network for reactive electric power in dependence on a voltage sensed in the transmission network. A voltage controller, in dependence on the difference of a reference value for the voltage and its sensed value, forms a reference value for a reactive power flow through the compensator. A transformation element represents the sensed voltage as a voltage vector in a rotating two-phase system of coordinates and forms a compensation signal in dependence on a sensed change of the angular position of the voltage vector in the two-phase system of coordinates. A summation element forms the reference value for reactive power flow through the compensator in dependence on the compensation signal.

Abstract: A hybrid reactive power compensation device comprises a passive type reactive power compensator and an active type reactive power compensator serially connected thereto. The passive type reactive power compensator is an AC power capacitor adapted to provide the reactive power that reduces capacity of the active type reactive power compensator. The active type reactive power compensator comprises a power converter, a DC capacitor, a high-frequency ripple filter and a controller. The hybrid reactive power compensation device can supply a linearly adjustable reactive power within a predetermined range, and is adapted to supply a current with a nearly sinusoidal waveform. Therefore, it can avoid the destruction of AC power capacitor caused by the power resonance.

Abstract: a voltage recovery device is configured to provide real and reactive power to a utility power network at a sufficient level and for a sufficient duration to recover the voltage on the utility power network within a predetermined proportion of the nominal voltage, following a fault condition detected on the utility power network. Moreover, the voltage recovery device reduces the overall transmission losses in a utility power system.

Abstract: A hybrid reactive power compensation device comprises a passive type reactive power compensator and an active type reactive power compensator serially connected thereto. The passive type reactive power compensator is an AC power capacitor adapted to provide the reactive power that reduces capacity of the active type reactive power compensator. The active type reactive power compensator is consisted of a power converter, a DC capacitor, a high-frequency ripple filter and a controller. The hybrid reactive power compensation device can supply a linearly adjustable reactive power within a predetermined range, and is adapted to provide with a serial-connected virtual harmonic damping. Therefore, it can avoid the destruction of AC power capacitor caused by the power resonance.

Abstract: According to some embodiments, a feedback circuit receives a signal, the signal corresponding to a proximity of an existing operation point of a system to a resonant operation point of the system, and determines if a self-impedance of the system should be changed based on the signal.

Abstract: A switching power supply including a power factor correction circuit comprises a rectifier, an inductor coupled in series with the rectifier, a semiconductor switch formed by a compensation device coupled in parallel with the rectifier and the inductor. The output circuit comprises a diode coupled in series with a capacitor both coupled in parallel with the semiconductor switch. An input current sensor, and a control unit for controlling the compensation device are provided.

Abstract: A universal electric energy saver to recuperate power losses comprised of a bank of condensers connected in parallel; a bank of resistors with some connected in parallel while others are connected in series; a transformer to step down the voltage to power up a small electronic circuit board which serves to absorb the lost power and protect the rest of the circuitry against overload; a line plugging into a power outlet to connect the universal electrical energy saver with the rest of the electrical circuit.

Abstract: A switching arrangement for a high voltage load provides high voltage pulses to the load. The switching arrangement includes switching modules, where n is typically (75). A load capacitance is Cd is required to avoid voltage overshoot at the load and is provided by a capacitance of nCd arranged in parallel with each switch.

Abstract: A universal electrical energy saver to recuperate power losses comprised of a bank of condensers connected in parallel; a bank of resistors with some connected in parallel while others are connected in series; a transformer to step down the voltage to power up a small electronic circuit board which serves to absorb the lost power and protect the rest of the circuitry against overload; a line plugging into a power outlet to connect the universal electrical energy saver with the rest of the electrical circuit.

Abstract: In a power supply apparatus for discharge surface treatment which uses a green compact electrode as a discharge electrode, allows a pulse-type discharge to take place between said discharge electrode and a workpiece, and forms a film, which is made of an electrode material or a material obtained when the electrode material reacts to a discharge energy, on a surface of the workpiece following three measures are taken. (1) When a discharge voltage detected by the voltage detection means is less than or equal to discharge detection voltage set value which is slightly lower than a power supply voltage, the electric current cut-off means forcibly cuts off an output of the oscillator so that long-time pulse is prevented. (2) A capacitor is connected in parallel with an oscillation circuit of the oscillator, and the long-time pulse is prevented by capacitor discharge. (3) Time that the discharge takes place once is controlled by a timer so that the long-time pulse is prevented.

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: In a power supply apparatus for discharge surface treatment which uses a green compact electrode as a discharge electrode, allows a pulse-type discharge to take place between said discharge electrode and a workpiece, and forms a film, which is made of an electrode material or a material obtained when the electrode material reacts to a discharge energy, on a surface of the workpiece following three measures are taken. (1) When a discharge voltage detected by the voltage detection means is less than or equal to discharge detection voltage set value which is slightly lower than a power supply voltage, the electric current cut-off means forcibly cuts off an output of the oscillator so that long-time pulse is prevented. (2) A capacitor is connected in parallel with an oscillation circuit of the oscillator, and the long-time pulse is prevented by capacitor discharge. (3) Time that the discharge takes place once is controlled by a timer so that the long-time pulse is prevented.

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: A power factor correction (PFC) circuit with a resonant snubber. The power factor correction (PFC) circuit has an input part (601) for receiving an AC voltage and outputting a first DC voltage; a main part (604) for converting the first DC voltage to a second DC voltage; and a snubber (500) for ensuring the main part operates in soft turn-on and soft turn-off. The main part (604) has a primary inductor and a primary diode connected in series, and a switch (606) connected to the connection node of the primary inductor and the primary diode. The snubber (500) has a cascaded device (a first diode and a resonant inductor connected in series) and a second diode connected in series, and a resonant capacitor connected between the connection node of the cascaded device and second diode, and the switch (606).

Abstract: A circuit for converting AC voltage into DC voltage for one or two devices (Rm, Ra), includes a first part of the current being fed to the input side via a large induction coil (L50) and a first rectifier (Gm), and a second part of the current being fed via a second rectifier (Ga) upstream of the large induction coil. On the output side, behind the second rectifier (Ga), a switched-mode power supply is arranged, preferably in the form of an up-converter or a flyback converter (10). The division of the applied current for smoothing the output voltage provides that the induction coil (L50) can be accordingly dimensioned smaller and, despite this, the circuit can also satisfy relevant standard specifications.

Abstract: A load current compensated voltage sampling circuit is characterized by a sampling voltage that is compensated by utilizing different load current values of the detected sample as parameters for transforming into the intended display target value.

Abstract: An electrical power supply unit powers a load, in particular a transformer (8), from a power source (10) via electrical switchgear (14), in particular a circuit-breaker, and it includes an interference attenuator (16) of the ferrite type for attenuating interference due to switching. The attenuator (16) is placed between the power source (10) and the electrical switchgear (14), thereby contributing to reducing the extent of the interference significantly.

Abstract: A feedback circuit is provided for reducing the input impedance of a preamplifier circuit, such as for use with a sensing coil in an imaging system. The feedback circuit permits adjustment of the input impedance by balancing inductive and capacitive components of a feedback control circuit. The imaginary component of the input impedance may be adjusted independently of the real component, to provide a substantially zero input impedance, while allowing adjustment of the stability of the system. The circuitry may function in conjunction with a reactance matching circuit to reduce cross-talk in multiple sensing coil arrangements.

Abstract: A system for compensating a voltage fluctuation in a transmission line of a power system is such that a power detection circuit detects a voltage and power flow in the transmission line involving a voltage fluctuation to be compensated, a calculation circuit calculates an impedance compensation amount for adjusting a voltage on the transmission line on the basis of the voltage and power flow detected by the detection circuit and a control circuit controls an adjusting device on the power system on the basis of the impedance compensation amount calculated by the calculation circuit.

Abstract: A pair of equivalent controlled impedance buffers are connected in a push-pull configuration to a transformer primary coil. A pair of equivalent pre-drivers are connected to the pair of buffers. Each pre-driver receives a driver input signal and outputs a buffer input signal (based on the input signal) and a DC offset compensation signal. Each buffer receives the buffer input signal from its associated pre-driver for buffered output as a line driver signal to the primary coil. Each buffer further receives the DC offset compensation signal generated its pre-driver to compensate for an offset introduced by the transformer. A balanced bridge hybrid is also connected between the buffer output and internal nodes. An adjustment circuit processes the hybrid output during training mode to generate an adjustment signal for application to an adjustable current source within each buffer.

Abstract: A single phase power supply for electric arc welders comprising: a full wave rectifier forming the input of said power supply; a valley fill power factor correcting circuit for controlling input current flow to the rectifier and creating an high crest factor intermediate voltage; a converter forming the output of the power supply for converting the intermediate voltage into a generally ripple free DC voltage; and, switching means in the converter for controlling the output voltage of the converter to a level in the general range of 20-100 volts for welding.

Abstract: The controller for a power converter of the present invention, connects a transformer in series with the AC system, and has devices which find the voltage drop portion generated by the impedance of this transformer when introducing a voltage in series by an inverter into the above-mentioned AC system via this transformer, and control the output of the above-mentioned inverter to compensate this voltage drop portion.

Abstract: A system for regulating the voltage by switching capacitor banks and for preventing damage due to harmonic resonance in an AC power supply line after a capacitor bank is switched. The system includes a detector for detecting the harmonic distortion in the supply line, and multiple capacitor banks connected in parallel to the supply line. At least one switch is in series with each capacitor bank to connect or disconnect the capacitor bank to the supply line. A controller operates the switches and receives input from the detector. After a capacitor bank is switched to improve conditions in the supply line, the controller compares the total harmonic distortion to an action threshold and switches capacitor banks as programmed when the total harmonic distortion exceeds the action threshold for a predetermined period of time in order to avoid a resonant condition that could cause damage to equipment.

Abstract: An energy management system designed to reduce the costs of electrical energy particularly applicable to service businesses such as restaurants, service stations, convenience and grocery stores and the like. The system includes controllers to sequentially and in a predetermined manner initiate operation of a plurality of loads such as appliances and other devices thereby to reduce the demand rate for electricity. A plurality of operating modes are designed for the particular loads or devices and determine the quantity of energy needed under various operating conditions, the operating modes consuming reduced power and generally being associated with a duty cycle. A capacitance bank is associated with those loads having motors to increase the power factor when the motors are under operation. A timer may automatically initiate and terminate operation of the motor and the associated capacitance bank.

Abstract: A method and apparatus for controlling power transferred and regulating voltage in a multi-phase transmission line includes generating a first plurality of voltages, a second plurality of voltages displaced in phase from the first plurality of voltages, and a third plurality of voltages displaced in phase from the first and second plurality of voltages. The first, second and third plurality of voltages are selectively connected in series in each line of the multi-phase transmission line.

Abstract: An electrical power transmitting system (50) in accordance with the invention includes an alternating current electrical power generator (12) for producing alternating current on an output having a specified maximum; at least one electrical load (22) which is coupled to a point of regulation (16) in the electrical transmitting system; a feeder (14) having a specified maximum voltage drop, a length extending between the output and the point of regulation for transmitting the alternating current to the point of regulation, an inductance having an inductive reactance at a fundamental frequency of the alternating current, a capacitance (54, 66, 80 and 100) in series with the inductance having a capacitive reactance at the fundamental of the frequency of the alternating current which cancels at least part of the inductive reactance at the fundamental frequency of the alternating current to provide a reduced impedance in the feeder at the fundamental frequency of the alternating current to produce a reduced voltage

Abstract: A device for detecting the short circuiting of the switches of a converter circuit arrangement is disclosed. The device is magnetically coupled to the current limiter coil and comprises a conductor loop which is preferably arranged at the end of the current limiter coil. On short circuiting, a voltage is induced in the conductor loop. This voltage is converted in a detection circuit into a voltage pulse and fed to an evaluation logic circuit. In the evaluation logic circuit, the period of the induced voltage pulse is evaluated and, if appropriate, load-relieval actuation is initiated.

Abstract: A series-compensated converter station in an installation for transmission of high-voltage direct current is connected to an alternating-voltage network (N) with three phases (A, B, C, respectively). The converter station comprises at least two direct-voltage series-connected six-pulse converter bridges (SR1, SR2, respectively), a three-phase transformer coupling with two secondary windings (SW1, SW2, respectively), and a star-connected primary winding (PW) with a neutral point (NP) connected to ground as well as a series capacitor unit (CN) for each one of the three phases. Each one of the converter bridges is connected to a respective secondary winding and the primary winding is connected to the alternating-voltage network via the series-capacitor units. The transformer coupling exhibits a high impedance to zero-sequence currents through the primary winding of the transformer coupling.

Abstract: A circuit for correcting perturbations in a power system signal operating at a system line frequency includes a capacitor for drawing a capacitive current and a first inductor for drawing an inductive current substantially equal in amplitude and substantially one hundred eighty degrees out of phase with the capacitive current. The first inductor is connected in parallel with the capacitor to form a storage module for storing energy therein wherein the storage module is tuned to resonate at the system line frequency and wherein the storage module is connected in parallel across the load. A second inductor connected in series between a power source and the load isolates the power source from the load while a second capacitor in series with the second inductor, which together are tuned to resonate at the system line frequency, prevents voltage drop across the second inductor with linear loads.

Abstract: The invention is a static VAR compensator (SVC) which provides optimized power factor correction in the presence of resonant line conditions and large amplitude harmonics. A gate drive signal is applied to the solid state devices of the SVC during only a minor fraction of the fundamental cycle to prevent damage to the solid state devices and the capacitors of the SVC, otherwise caused by resonant line conditions or large amplitude harmonics. This relatively short gate drive signal, in the presence of large amplitude harmonics, will force the solid state electronic components to turn-off prematurely. As a result, the capacitors of the SVC provide incomplete reactive power compensation. Feedback from a capacitor polarity circuit is used to determine switched capacitor status at a specific instant in each cycle. A VAR correction controller, responsive to the feedback, executes a control scheme to account for incomplete reactive power compensation.

Abstract: A power factor corrected rectifying circuit is disclosed. The invention may be implemented using only passive elements and, in such an embodiment, achieves a power factor of about 80%. The invention comprises two rectifying circuits for providing two rectified current paths from an AC input port to an output port. The coupling of current along one of the rectified current paths is delayed. As the sum of the delayed and undelayed currents, the input current pulse is widened to approximate a sinusoid, thereby increasing the power factor.

Abstract: A power line conditioner includes an active filter coupled, in series, and a passive filter coupled, in parallel, to a three-phase power distribution network. The three-phase power distribution network includes a voltage source that induces three-phase input currents at a first end of the three-phase power distribution network. A load, circulating three-phase load currents, is positioned at a second end of the three-phase power distribution network. The active filter controller of the invention uses synchronous transformations to identify selected harmonic reference components corresponding to individual harmonics of the three-phase load currents. The selected harmonic reference components are multiplied by a predetermined factor corresponding to a permissible percentage of the individual harmonics that may be injected into the supply voltage. This results in active filter reference signal components that are applied to the active filter.

Abstract: Single and polyphase a.c. induction devices, such as: motors, generators, transformers, welders, ballasts, etc. are so wound as to maximize performance and efficiency. For each phase of such device this invention utilizes a combined pair of windings which are conductively and inductively dependent. An energy supply winding of each combined pair is electrically connected to a corresponding input/output phase, while the remaining, or reflux, winding of each pair is electrically connected in series with a tunable capacitive element and to neutral or electrical ground by means of a linear and non-linear resistive means.

Abstract: The present invention provides means to instantaneously optimize reactive kva for an a.c. power system containing both linear and non-linear reactive loads. The preferred means utilizes a reflux transformer which is tuned for maximum energy transfer between primary and secondary windings. Each secondary winding is connected in series with a variable inductor and a fixed capacitive means, so as to continuously reflect variable reactive kva to the power system via the primary and secondary windings. The reactive kva requirements of the power system can thus be continuously optimized without destructive voltage transients associated with switching graduated units of fixed capacitive compensation or incurring the risk of conducting series resonant currents associated with non-linear loads.

Abstract: An impedance compensator for adjusting the power factor of a power distribution system by directly measuring impedance at a point in the power distribution system and dynamically adjusting that impedance to be resistive yielding a power factor of one. The compensator dynamically inserts and removes both capacitance and inductance to adjust the impedance. The inductance is utilized to make coarse adjustments to the impedance, whereas the capacitance is utilized to make fine adjustments.

Abstract: A compensating circuit arrangement for a power transmission system for rapidly inserting capacitance into a transmission line for desired portions of cycles of the operating frequency of the system, has first anti-parallel connected thyristors in series with a capacitance and second anti-parallel connected thyristors in parallel with the series connected first thyristors and the capacitance. A control responsive to a variable in the system, and related to system reactance, switches desired thyristors on at desired times during a cycle of operating frequency to introduce controlled amounts of capacitance into the power transmission system.

Abstract: A microcomputer that reduces through current of output buffers, and thus, reduces power line fluctuation that occurs when a large number of the bus lines connected to output buffers change state at the same time. The through current (or punch-through current) is reduced through the use of a detector circuit that detects the number of bus lines which are changing state and a decoder circuit that changes the impedance of output buffers, which drive the bus lines to external components, when the number of bus lines changing state at a given time exceeds a predetermined number.

Abstract: An improved power factor DC power supply in accordance with the present invention (100 or 200) employs a power factor correcting network ( 120), a full-wave rectifier means (122), a pair of filter capacitors (124 and 126 ) , and three current steering diodes (128, 130 and 132). The power factor correcting network ( 120) includes both an inductor means (136 and 240) and a capacitor (138), the combination configured to improve the power factor DC power supply (100 or 200) presents to the AC power-line (102) by reducing the level of harmonic currents the DC power supply generates on the AC power-line. The filter capacitors (124 and 126) are configured with the current steering diodes (128, 130 and 132) such that the filter capacitors are charged in series and discharged in parallel.

Abstract: A capacitor bank installation for generating reactive power in high or extra high voltage electrical power systems, for example 345kV, to maintain the voltage level during heavy loading conditions or system contingencies. A three phase capacitor bank is connected between the high voltage line and the low voltage line by a first switching device which is connected between the high voltage line and the capacitor bank and by a second switching device which is connected between the capacitor bank and the low voltage line. The first switching device is a current interrupting device in series with a motorized disconnect switch which has a lower recovery voltage withstand capability than would be required if switching a shunt capacitor bank connected to the high voltage system. The second switching device is a motorized disconnect switch without any current interrupting capability.

Abstract: A filter network adapted to be placed in parallel with a power supply which provides a high impedance to the 60 Hz utility frequency but acts like a short circuit to all higher frequencies. The network comprises a plurality of parallel circuits, each of which comprise a capacitor, an inductor and a resistor in series with a second resistor coupled in parallel with the inductor. Signal levels above 60 Hz in a prototype circuit using seven such parallel circuits with a parallel capacitor coupled thereto shows that above 60 Hz the signal from the power supply is attenuated by 25-30 dB at 1 KHz and that the impedance is substantially resistive beyond 1 KHz. To maximize the power factor of the circuit comprising the network and consequently the dynamic range of audio equipment coupled thereto, the magnitude of the total capacitance of the network is chosen to be as close as possible to the magnitude of the input inductance of the audio equipment.

Abstract: A circuit for correcting power factor and for reducing ac line current harmonic components in conjunction with bridge-connected capacitive-filtered loads and for providing a source of ac startup current for associated circuitry, for example a switch mode power supply which may form part of the load. The circuit comprises a rectifier bridge, a dual-tuned circuit having a tuned filter in series between an ac line input and the bridge, and a shunt capacitor across the input to the bridge. The tuned filter comprises a parallel connected inductor and capacitor, the shunt capacitor being tuned with the inductor to form a trap filter to reduce third-order and higher harmonic components in the ac line current. The circuit also includes a current source operatively connected to the shunt capacitor for providing a source of ac current immediately upon application of ac power to the ac line input.

Abstract: An arrangement includes a network for connection between an AC power supply and the input of a DC power supply containing rectifiers and a filter capacitor. The network forms a fourth order, damped lowpass filter that waveshapes the AC input current so as to either reduce or remove the magnitude of harmonics which primarily cause distortion of the input current waveform. In one embodiment, the waveshaping network includes a tapped inductor connected in series with the input of the DC power supply. A series combination of a damping resistor and a first capacitor is connected in parallel with the series inductor. One end of a second capacitor is connected to the tap of the inductor. The waveshaping network increases the power factor and lowers the total harmonic distortion the input of the DC power supply presents to the AC power supply.