Abstract: An apparatus for impedance matching of an electrical load to a generator has input connections for connection to the generator and output connections for connection to the load. The apparatus has a converter which connects the input connections to the output connections. An input voltage which is applied between the input connections can be converted into an output voltage. The converter has energy storage means connected to one of the output connections by an active diode, a controllable switching device, and an actuation device. The switching device can be moved to a first and a second switching state so that energy from the generator is stored in the energy storage means in the first switching state. Energy which is stored can be output to the load in the second switching state. A detector is connected to the input connections for detecting a measurement signal for the impedance matching. The actuation device has an activation signal and can be moved to a first and a second operating state.

Abstract: An AC/DC converter includes a rectifier circuit and a power factor correction circuit. An input port of the rectifier circuit receives an alternate current. The power factor correction circuit includes a first inductor, a second inductor, a first capacitor, a second capacitor, a first diode and a second diode. An end of the first inductor electrically connects to a positive pole of an output port of the rectifier circuit, and the other end electrically connects to a ground terminal of the output port through two parallel series routes which are bridged by the first diode. Wherein a series route contains the first capacitor and the second diode, and the other series route contains the second inductor and the second capacitor. The second capacitor is provided for parallel connecting with a loading. In this way, the input current could be controlled to increase the power factor effectively.

Abstract: Circuits and methods relating to the provision of a reactive current to ensure zero voltage switching in a boost power factor correction converter. A simple passive circuit using a series connected inductor and capacitor are coupled between two phases of an interleaved boost PFC converter. The passive circuit takes advantage of the 180° phase-shift between the two phases to provide reactive current for zero voltage switching. A control system for adjusting and controlling the reactive current to ensure ZVS for different loads and line voltages is also provided.

Abstract: Provided are a control-amount separating section that separates, when it is determined that an interconnection-point voltage (Vr) at an interconnection point where a wind turbine is connected to a utility grid deviates from a target value, a target control amount for reactive power for matching the interconnection-point voltage (Vr) with the target value into a first control amount serving as a control amount for reactive power that is caused by a fluctuation in active power at the interconnection point and a second control amount serving as a control amount for reactive power that is caused by a change in a power flow in the utility grid; a wind-turbine control device that controls the switching device on the basis of the first control amount; and a capacitor-bank control device that controls the capacitor bank on the basis of the second control amount.

Abstract: Methods and systems of network voltage regulating transformers are provided. A network voltage regulating transformer (NVRT) may provide voltage transformation, isolation, and regulation. A NVRT may further provide power factor corrections. Multiple NVRTs may operate autonomously and collectively thereby achieving an edge of network voltage control when installed to a power system. A NVRT comprises a transformer, a VAR source, and a control module. The input current (i.e., the current through the primary side of the transformer), the output current (i.e., the current through the secondary side of the transformer), and/or the output voltage (i.e., the voltage across the secondary side of the transformer) may be monitored.

Abstract: Methods and apparatus for zero current detection and discontinuous conduction mode digital detection for a boost power factor correction converter based on a digital signal processor are disclosed. By effectively using resources in a processor with integrated high-speed comparators, simple detection can be accomplished with cost and performance over alternative detection methods. The methods and apparatus can be employed in an adaptive digital controller for mixed-conduction mode in the converter and can provide for lower total harmonic distortion and greater power factors than a non-adaptive controller.

Abstract: A compensator for balancing an ac voltage network with a load connected between two phases. The compensator includes a voltage-source converter and a balancing device. The balancing device includes an inductance connected between phases before the load.

Abstract: Embodiments of the invention include an electronic load having variable reactive load capability and techniques for controlling and/or modeling a reactive component in a load. The electronic load can include a user interface through which a latency value is received from a user. A delay is created based on the latency value between the time that a variable of the input signal is sensed and the time that a variable of the input signal is driven to a new value, thereby simulating a reactive component in the electronic load based on the created delay. In one example embodiment, the driven variable can be stepped after the created delay to produce an approximation of a capacitive or inductive element. In another example embodiment, the driven variable can be slewed during the delay period using an arbitrary waveform generator, thereby more accurately simulating the reactive component.

Abstract: A circuit arrangement is for operating a load having a reactive characteristic on an AC power supply. The circuit arrangement enables the best possible reactive power compensation, that is, enables operation close to a cos ? of 1, in order to increase the overall efficiency of the arrangement or to achieve optimal energy savings. In order to control critical operating states, a feedback loop is provided that supplies a control current to a further reactive circuit element. This further circuit element is arranged parallel to the load or to the power factor correction capacitor, and is acted upon by a control current such that the control current counteracts a change in the reactive component of the load. The control current is derived from the load current as a variable proportional to the load current. In this way, a reactor for optimizing electromagnetic consumption is created.

Abstract: A power factor correction (PFC) controller includes a capacitor, an error amplifier, a switching frequency adjuster, a comparator, and a drive signal generator. The current source generates a current that is representative of an instantaneous input voltage of a PFC converter to charge the capacitor when a power switch of the PFC converter is off. The switching frequency adjuster generates an adjusted error signal in response to an error signal generated by the error amplifier. The comparator compares a voltage on the capacitor with the adjusted error signal to generate a first signal to end an off time of the power switch. The drive signal generator controls switching of the power switch in response to the first signal. The switching frequency adjuster changes the adjusted error signal in response to changes in the error signal to adjust an average switching frequency of the power switch.

Abstract: A modular multilevel converter system. The system includes a plurality of series connected two-terminal M2LC cells arranged into at least two output phase modules. A first one of the output phase modules has an inductance and an effective capacitance associated therewith. The first one of the output phase modules is configured so that a natural resonant frequency of the inductance with the effective capacitance of the first one of the output phase modules is greater than at least one of the following: an operating frequency of the first one of the output phase modules; a switching frequency of the first one of the output phase modules; and a switching frequency of any of the M2LC cells of the first one of the output phase modules.

Abstract: A power converter utilizes one or more nonlinear composite film capacitors constructed solely of polymer anti-ferroelectric (AFE) particle composites and configured as DC-link bus capacitors providing an energy buffer to reduce DC-link voltage ripple.

Abstract: An arrangement for exchanging power, in shunt connection, with a three-phase electric power network includes a Voltage Source Converter having at least three phase legs with each a series connection of switching cells. Each switching cell has at least two semiconductor assemblies connected in series and having each a semiconductor device of turn-off- type and a rectifying element connected in anti-parallel therewith and at least one energy storing capacitor. A control unit is configured to control the semiconductor devices of each switching cell and to deliver a voltage across the terminals thereof being zero or U, in which U is the voltage across the capacitor. The control unit is also configured to calculate a value for amplitude and phase position for a second negative sequence-current or a zero-sequence voltage or a value of a dc current.

Abstract: In one example embodiment, a power control system includes one or more stages, a plurality of primary busbars operatively coupled to the one or more stages, and an intelligent controller operatively coupled to the one or more stages. Each of the one or more stages is configured to generate a lead current when coupled in parallel to a power distribution system, and at least one of the one or more stages comprises a notch filter and a power tank circuit. Each of the plurality of primary busbars is configured to carry one phase of a multiple phase power signal. The controller is configured to determine when to switch each of the one or more stages one and off, to count a number of times each stage is switched on, and to track one or more electrical parameters of the power distribution system, power control system, or both.

Abstract: Embodiments of the invention include an electronic load having variable reactive load capability and techniques for controlling and/or modeling a reactive component in a load. The electronic load can include a user interface through which a latency value is received from a user. A delay is created based on the latency value between the time that a variable of the input signal is sensed and the time that a variable of the input signal is driven to a new value, thereby simulating a reactive component in the electronic load based on the created delay. In one example embodiment, the driven variable can be stepped after the created delay to produce an approximation of a capacitive or inductive element. In another example embodiment, the driven variable can be slewed during the delay period using an arbitrary waveform generator, thereby more accurately simulating the reactive component.

Abstract: Described is a controller, wherein the controller is adapted: to control a transformation ratio of a park transformer of a wind turbine park including wind turbines connected to a first node. The park transformer is connected between a first node and a second node which is connected to a utility grid to which electric energy produced by the wind turbines is to be delivered. Further a wind park and a control method are described.

Abstract: An energy optimization alternating current power balancing system for a three phase alternating current power source using various configurations of chokes, wire inductors and capacitors connected across and in parallel to each power lines from the alternating current power source. An inductor in the alternating current power-balancing device or system is connected in series to the neutral line of the alternating current power source to create a more balanced power distribution system by improving the power factor and increasing the efficiency of energy consumption in multiphase alternating current power source.

Abstract: A bridgeless PFC circuit is provided. A low-frequency bridge leg includes a first diode and a second diode connected in series; a three-port network includes a switch tube and an inductor; a lightning and surge protection bridge leg includes a third diode and a fourth diode connected in series; a capacitor is connected between terminals of the low-frequency bridge leg, and between terminals of the lightning and surge protection bridge leg; a common terminal of the first and second diodes is connected to a terminal of an AC power, and a common terminal of the third and fourth diodes is connected to the other terminal; and the three-port network has two ports with the capacitor connected therebetween, and another port connected to the common terminal of the third and fourth diodes. Thus, EMI performance and efficiency can be improved and costs of the whole circuit can be lowered.

Abstract: An arrangement for exchanging power with a three-phase electric power network includes a Voltage Source Converter having three phase legs with each a series connection of switching cells. The three phase legs are interconnected in a neutral point by forming a wye-connection. The arrangement also includes a device connected to the neutral point of the converter and configured to provide a current path for a zero-sequence current. A control unit is configured to calculate a value for amplitude and phase position for a zero-sequence current for which, when added to said three phase legs upon generation of a negative-sequence current, the resulting energy stored in energy storing capacitors in each phase leg will be constant and to control semiconductor devices of said switching cells to add such a zero-sequence current to the currents of each phase leg of the converter.

Abstract: An apparatus and method for utilizing reactive power in electric power generating facilities. The primary energy source is a reactive power provided by a source of high-frequency, high-voltage electromagnetic oscillations. As a device, the Reactive Current Transformer consists of a high-voltage, high-frequency electromagnetic generator, preferably Tesla Resonant Transformer and of inductive receiving coils, electromagnetically coupled in the absence of a ferromagnetic core, adjusted in resonance with this electromagnetic generator and mounted in any required quantity, close to it. Energy, emitted by the electromagnetic generator, is being transferred to inductive coils. Reactive current induced in the inductive coils can be collected from them and converted to a standard AC voltage for further use by any convenient way, preferably with a help of additional inductive transforming windings, mounted together and electromagnetically coupled with these inductive coils.

Abstract: A power factor correction of three-phase boost-type conversion is disclosed. Embodiments comprising multi-leg autotransformers are disclosed, e.g. comprising 3-phase low-pass filtering impedances such as capacitors between an input of a converter and a midpoint of the output.

Abstract: A harmonic input current reduction and power factor correction circuit for three phase, power supplies. The circuit includes passive elements including a series inductance and capacitor connected between each AC line of a three phase voltage source, and each input phase of the uncorrected power supply. The inductance and capacitor are designed and chosen to meet linearity and volt ampere requirements to achieve total harmonic current levels of less than 10%, and power factors greater than 0.98. This is achieved with less than 1% loss in line operating input voltage range and overall efficiency of greater than 99.5%. Further, the dynamic response of a circuit to power supply load transient demands is limited in voltage overshoot or undershoot effects.

Abstract: There is provided an inverter device capable of simplifying the circuit structure, lowering the cast, and downsizing of the device. The inverter device detects a switching change of an inverter by a pulse and is equipped with a pulse signal detector capable of detecting a motor residual voltage or a phase and a detector for detecting a residual voltage or a phase. The inverter device includes a voltage detector, a circuit for detecting a pulse signal based on a comparison between a phase voltage detection value per one phase output from the voltage detector and a first reference voltage value, a circuit for detecting a line residual voltage based on phase voltage detection values of two phases output from the voltage detector, and a circuit for detecting a line phase based on a comparison between the line residual voltage and a second reference voltage value.

Abstract: The disclosure specifies a method for operating a converter circuit, the converter circuit having a converter unit with a large number of drivable power semiconductor switches and with a three-phase electrical AC voltage system, in which the drivable power semiconductor switches are driven by means of a drive signal (SA) formed from a control signal ((SR), and the control signal (SR) is formed by adjusting an H-th harmonic component of system currents (iNH) to a system current setpoint value (iNHref), where H=1, 2, 3, . . . . In order to reduce a harmonic component in the system voltages, the system current setpoint value (iNHref) is formed by adjusting an H-th harmonic component of system voltages (uNH) to a predeterminable system voltage setpoint value (uNHref), the control difference (uNHdiff) from the H-th harmonic component of the system voltages (uNH) and the system voltage setpoint value (uNHref) being weighted by a system impedance (yNH) determined with respect to the H-th harmonic component.

Abstract: A one-phase static var compensator apparatus includes a compensator string consisting of a first static var compensator connected serially to a thyristor valve. The compensator string is arranged to be connected on its first end to one phase of a transmission grid of a rated voltage exceeding 69 kV. Moreover, the thyristor valve includes a plurality of thyristors connected serially and the compensator string is arranged to be directly connected to the transmission grid. A corresponding three phase apparatus is also presented.

Abstract: A power factor correcting power supply. The power factor correcting power supply includes a controlled current source for providing electrical power of a regulated current and a regulated voltage to a first output terminal, a voltage comparison current controller, and a control circuit responsive to the current at the output terminal, the control circuit coacting with the voltage comparison current controller to cause the controlled current source to increase or decrease the current at the first output terminal.

Abstract: A power-conversion regulator comprising an inductive reactor, an output filter reactor, and a switch for admitting energy to the inductive reactor, additionally comprises computation circuitry responsive to the flux in the inductive reactor, to a reference signal, to an output voltage, and sometimes to an output load current, for computing the quantity of energy that must be supplied to a load and to the output filter reactor to regulate the output voltage or current to a desired relationship with the reference signal during each chopping waveform cycle driving the switch. As the inductive reactor is charged from an input energy source, the computation circuitry predicts whether the energy in the inductive reactor has become adequate for the regulation.

Abstract: A power supply device includes first and second power factor correctors, and first and second resonant circuits. The first and second power factor correctors are for receiving an alternating current (AC) input voltage, and are driven by first and second driving signals for rectifying the AC input voltage to generate first and second driving voltages, respectively. The first and second resonant circuits are coupled to the first and second power factor correctors for receiving the first and second driving voltages, respectively, and have output sides that are coupled in parallel for outputting an output voltage.

Abstract: An AC-DC converter includes a rectifier DB for rectifying an alternating current supplied from an alternating power source AC, a power factor controller 11a connected to an output side of the rectifier DB to improve a power factor and also output either a power or a current limited to a predetermined value, a DC-DC converter 12 that converts a voltage outputted from the power factor controller 11 to another voltage, a capacitor EDLC for storing an energy and a two-way converter 13 having one input/output terminals connected to the output side of the power factor controller 11a and the other input/output terminals connected to the capacitor to carry out a two-way power conversion.

Abstract: A voltage sag correction device includes an input terminal adapted to receive a first operating signal having a line-to-neutral voltage. The first operating signal is provided to a load through an output terminal. A regulator module includes a rectifying device adapted to rectify a line-to-line input signal, a storage unit adapted to store energy corresponding to the rectified line-to-line input signal, and an inverter switching device adapted to use the stored energy to generate a correction signal during at least a portion of a voltage sag. An injection transformer in electrical communication with the regulator module is adapted to reduce a voltage of the correction signal. A bypass switch is in a closed position during a normal operating condition such that the injection transformer is bypassed. The bypass switch is in an open position during at least a portion of the voltage sag such that the injection transformer is energized.

Abstract: A power converter utilizes one or more nonlinear composite film capacitors constructed solely of polymer anti-ferroelectric (AFE) particle composites and configured as DC-link bus capacitors providing an energy buffer to reduce DC-link voltage ripple.

Abstract: An AC-DC power converter controls an external upstream switching device, which supplies it power to be converted. Power conversion is initiated when an external signal requests power be converted or when a program within the AC-DC power converter detects the need for power conversion. When this occurs, the AC-DC power converter signals the external switching device, which is upstream of the AC-DC power converter to turn on, thereby supplying the power to be converted to the AC-DC power converter.

Abstract: A method of controlling in-rush current to a DC motor is disclosed. The method may include operating the DC motor in a first mode including applying back-EMF across a relay coil to maintain the relay in an open configuration when the back-EMF is below a predetermined voltage. The method may also include operating the DC motor in a second mode including applying the back-EMF across the relay coil to maintain the relay in a closed configuration when the back-EMF is equal to or above the predetermined voltage.

Abstract: An indirect and passive method for AC/DC converter power factor correction is disclosed. The correction is achieved by stabilizing the input impedance of the converter with keeping the inversely proportional dependence between the current iconv(t) and voltage uconv(t) of the output smoothing filter (3). The necessary dependence is achieved by natural characteristics of circuit with passive components. An uncontrolled converter (6) with alternation of parallel and series resonance is used as such circuit. To increase the operating frequency of this converter, a chopper or an inverter is used. The resonant converter decreases the commutation current of the switches. Output voltage is easy to control by pulse width modulation of chopper or inverter. Passive power factor correction results in the total harmonic distortion of main current THDi=10 to 40 per cent. All currents of the converter are limited naturally in all operating modes.

Abstract: A device (8), for adjusting the impedance of a high voltage line (9), supplying an alternating current, has at least one control coil (2), which may be inserted in series in the high voltage line (9) and at least one switching device (3,10), provided for each control coil (2). The device is compact and economical. A control unit (4) for controlling each switching device (3,10) is also provided, such that the reactance of the control coil (2), acting in the device may be adjusted by the switching of the switching device (3,10), whereby each switching device (3,10) is arranged parallel to the corresponding control coil (2) in a parallel branch (5).

Abstract: A SVC control section detects a bus voltage from an instrument transformer, and adjusts reactive power generated by a SVC according to the detected bus voltage. A cooperative control section generates a control command for controlling the interconnection and parallel-off of a phase lead capacitor and a phase lag reactor on the basis of the amount of reactive power generated by the SVC and the bus voltage detected by the instrument transformer and a voltage sensor. A voltage comparator compares the bus voltage with a predetermined threshold voltage set to a voltage lower than a lower limit value of a steady state fluctuation range of the bus voltage and outputs the comparison result to a circuit breaker control section. When the bus voltage is lower than the threshold voltage, the circuit breaker control section locks the control command from the cooperative control section.

Abstract: An AC-DC converter includes a rectifier DB for rectifying an alternating current supplied from an alternating power source AC, a power factor controller 11 connected to an output side of the rectifier DB to improve a power factor, a DC-DC converter 12 that converts a voltage outputted from the power factor controller 11 to another voltage and also outputs either a power or a current limited to a predetermined value, a capacitor for storing an energy and a two-way converter 13 having one input/output terminals connected to output terminals of the DC-DC converter 12 and the other input/output terminals connected to the capacitor to carry out a two-way power conversion.

Abstract: A system and method for operating a Unified Power Flow Controller (UPFC) connected to a SCADA (Supervisory Control and Data Acquisition) are disclosed. The UPFC automatic operation system receives power system data from the SCADA system, automatically determines UPFC's optimum operation conditions according to power system states. The system includes: a UPFC acting as a serial/parallel FACTS to control variables of a power system; a SCADA for periodically acquiring line data of the power system and state data of the UPFC; and an upper controller for analyzing data received from the SCADA, and determining an UPFC's optimum operation mode for each power system condition and UPFC's optimum set-point control commands.

Abstract: A power-conversion regulator comprising an inductive reactor, an output filter reactor, and a switch for admitting energy to the inductive reactor, additionally comprises computation circuitry responsive to the flux in the inductive reactor, to a reference signal, to an output voltage, and sometimes to an output load current, for computing the quantity of energy that must be supplied to a load and to the output filter reactor to regulate the output voltage or current to a desired relationship with the reference signal during each chopping waveform cycle driving the switch. As the inductive reactor is charged from an input energy source, the computation circuitry predicts whether the energy in the inductive reactor has become adequate for the regulation.

Abstract: An apparatus, system and method are described that enable an impedance of a plasma load to be matched with a power generator. In some embodiments the apparatus includes a power output adapted to apply power that is utilized to energize a plasma; a sensor adapted to sample power applied at the power output so as to obtain power samples; and an impedance control output configured to provide, responsive to the power samples, an impedance-control signal that enables an impedance matching network connected to the output of the power generator and to the impedance control output to match, responsive to the an impedance-control signal, the impedance of the plasma to the operating impedance of the power generator.

Abstract: A method of power factor correction without using current sensing or a multiplier is disclosed. A generated predictive pulse is used to charge and discharge a PFC inductor in such a way that the current in the PFC inductor has a similar phase angle as the input AC voltage. Each ON portion of the pulse is used for charging while each OFF portion is used for discharging. As the input voltage increases in phase, the predictive pulse gradually increases in ON time duty and the PFC inductor is charged in increasing amount and discharged in decreasing amount per pulse. When peak is reached the duty ratio is reduced each pulse and the PFC inductor current is reduced along with the input AC voltage source until phase angle reaches 180 degrees and the ON time becomes zero.

Abstract: A flicker improvement effect evaluating system evaluates an effect of improvement of voltage flicker in a power system to which a static reactive power compensator is to be introduced. A system voltage operating unit operates a compensation current and a system impedance of the power system, based on actually measured data of system voltage and load current read from a data reading unit. Based on the results of operations and the actually measured data, a not-yet-improved system voltage at present and an improved system voltage attained when the static reactive power compensator is provided on a bus are simulated. By a flicker meter, flicker values of the not-yet-improved system voltage and improved system voltage amplified by an amplifying circuit are measured, and from the flicker values, the rate of improvement attained by the static reactive power compensator is operated.

Abstract: A power supply for a two-wire load control device supplies power to a microprocessor, which in turn controls the power supply. The power supply comprises an energy storage element, e.g., a capacitor, for producing a DC voltage for powering the microprocessor. The power supply comprises a high impedance circuit for allowing the energy storage element to receive energy at a first rate before the DC voltage is produced and the microprocessor is powered. The power supply further comprises a low-impedance circuit, i.e., a resistor in series electrical connection with a controllably conductive device, for allowing the energy storage element to receive energy at a second rate greater than the first rate. After starting up, the microprocessor is operable to selectively enable and disable the second energy-receiving circuit by rendering the controllably conductive device conductive and non-conductive, respectively.

Abstract: An active loading-reduction device is provided for a circuit. The circuit has functional circuitry coupled to a terminal to receive an alternating voltage. The circuit also has an electrostatic discharge protector that is coupled to the terminal. The active loading-reduction device includes active circuitry that is adapted to be coupled to a power supply to provide a reactance to counteract a reactance provided by the electrostatic discharge protector at the terminal of the circuit.

Abstract: A device, a system, and a method for preventing power-producing wind turbine generators from tripping due to the detection of a low-voltage condition on a power grid are disclosed. The disclosed device includes a resistor bank that absorbs real power and a control system that maintains the collector bus voltage above a threshold voltage level during the duration of low-voltage condition on the power grid. Collector bus voltage is maintained using gating signals that include phase delay angles to adjust the opening/closing of the switching devices.

Abstract: Method in low voltage net data transmission system for keeping the signal level of transmission constant on the net voltage rail or on wall outlet. In the method the feedback signals are taken wired or wirelessly from one or some locations of the actual apparatus or supply cable to the measuring and handling unit (60) of transmitting signals and further to the process unit (70) of sample and holding circuits (S & H) or of corresponding means and control means (CONTROL), by which unit the control signal (URC) and/or ULC) is taken to steer the output signal or output voltage of blocks (10, 20, 40 and/or 50) in a depending way from load impedance (ZLOAD) and from the series impedance (ZW) of supply cable (LW) so that the amplitude (ULOAD) of transmission signal level (ULOAD) on voltage rail or some location of the supply cable or on wall outlet is constant or almost constant.

Abstract: Disclosed is an actuating circuit and method for actuating a switch regulating the power consumption in a power factor correction circuit having input terminals for applying an input voltage and output terminals for providing an output voltage. The switch is cyclically turned on for an on-time and turned off for an off-time, the on-time having a first on-time period and a second on-time period directly adjacent to the first on-time period. A length for the first on-time period is dependent on the control signal, and a length for the second on-time period is proportional, at least for a prescribed range of values for an instantaneous value of the input voltage, to a quotient with a first first-degree function for the instantaneous value in the denominator and a second first-degree function for the instantaneous value in the numerator, with function values for the first function increasing as the instantaneous value rises.

Abstract: A method and an apparatus for reducing energization transients in a three phase AC power system which includes an electrical device having legs A, B and C associated with corresponding phases of the power system. The method includes the steps of connecting the legs of the device with the power system in an order determined by an energization sequence, wherein the energization sequence is either ABC or ACB. The apparatus includes a three phase electrical device having legs A, B, and C associated with corresponding phases of a three phase AC power system and switches operable to connect the legs of the device with the power system, wherein the switches are configured to be actuated in an order determined by an energization sequence, and wherein the energization sequence is either ABC or ACB. The switches may be controlled by a switch controller.

Abstract: A capacitor multiplier including a capacitor, a first voltage follower, a first impedance element, and a second impedance element is provided. The input terminal of the first voltage follower is electrically connected to the first terminal of the capacitor. Wherein, the voltage level of the output terminal of the first voltage follower changes along with the voltage level of the input terminal thereof. The first terminal of the first impedance element is electrically connected to the first terminal of the second impedance element. The second terminal of the first impedance element is electrically connected to the first terminal of the capacitor. The second terminal of the second impedance element is electrically connected to the output terminal of the first voltage follower.

Abstract: A reactive power control apparatus for an AC power system includes a reactive power compensation device, a compensation capacitor device and a compensation capacitor control device. The compensation capacitor control device includes a detection voltage output circuit which outputs a bus detection voltage after the clearing of a voltage drop abnormality, corresponding to the AC voltage of a system bus after the voltage drop abnormality that occurred in the AC power system has been cleared, and a compensation capacitor control circuit which controls the connection status of a compensation capacitor with respect to the system bus. The compensation capacitor control circuit controls the connection status of the compensation capacitor with respect to the system bus, on the basis of the voltage level of the bus detection voltage after the clearing of the voltage drop abnormality.