Abstract: A switching regulator is provided which can prevent overshooting in an output voltage even when a source voltage is returned to a normal voltage from a voltage lower than a desired output voltage of the switching regulator. The switching regulator includes a 100% duty detector circuit that detects that a PWM comparator is in a 100%-duty state and a discharge accelerator circuit that detects that the output of an error amplifier discharges the voltage of a phase compensating capacitor and that accelerates the discharge, and activates the discharge accelerator circuit when the 100% duty detector circuit detects the 100%-duty state.

Abstract: A PFC (Power Factor Correction) circuit improves the power factor of rectified power. Upon receiving output of the PFC circuit, a first DC-DC converter generates a voltage to be supplied to a load. Upon receiving output of the PFC circuit, a second DC-DC converter and a third DC-DC converter generate a control voltage. The second DC-DC converter and the third DC-DC converter are cascade-connected. An input terminal of the third DC-DC converter is connected to both an output terminal of the second DC-DC converter and an output terminal of the first DC-DC converter.

Abstract: A linear light-emitting diode (LED)-based solid-state universal lamp using an all-in-one LED driving circuit with a power factor correction (PFC) and control device operates normally for a regulated power and current from either electronic ballast or AC mains. The all-in-one LED driving circuit is configured to operate in a wide range of input voltages and frequencies, especially for various high voltages and high frequencies associated with various electronic ballasts. With a cycle-by-cycle current control and power switching at a constant on-time and varied off-time, an over-rated surge current is limited, preventing occasional fire hazards occurred in the ballast. When two shock protection switches are used in two lamp bases in the lamp, the universal lamp fully protects a person from possible electric shock during initial installation and re-lamping.

Abstract: In DC/DC converter circuit, the peak value of the reactor current is found based on output voltage and an input voltage, thereby, the operation with the predetermined electric current mode is thereby enabled. The AC/DC converter circuit is run with a predetermined current mode, the power factor improvement is accomplished. The first control part 211 inputs a detected value of output voltage Eo, and a turn-off timing predicted value of switch Tr of the DC/DC converter 1 is calculated. The first control part 211 sends the calculation result to the switch drive signal generate part 213. The second control part 212 inputs the detected value of the output voltage and the input voltage, and it receives the turn-off timing predicted value from the first control part 211.

Abstract: A power flow controller with a fractionally rated back-to-back (BTB) converter is provided. The power flow controller provide dynamic control of both active and reactive power of a power system. The power flow controller inserts a voltage with controllable magnitude and phase between two AC sources at the same frequency; thereby effecting control of active and reactive power flows between the two AC sources. A transformer may be augmented with a fractionally rated bi-directional Back to Back (BTB) converter. The fractionally rated BTB converter comprises a transformer side converter (TSC), a direct-current (DC) link, and a line side converter (LSC). By controlling the switches of the BTB converter, the effective phase angle between the two AC source voltages may be regulated, and the amplitude of the voltage inserted by the power flow controller may be adjusted with respect to the AC source voltages.

Abstract: The present invention includes: a series circuit including a reactor and a switching element connected between the rectified-current output terminals of a rectifier; a series circuit including a diode and a smoothing capacitor for obtaining an output voltage, connected in parallel to the switching element; an error amplifier configured to detect the output voltage, amplify the error between the detected output voltage and a reference voltage, and output an error signal; a zero-current detector configured to output a signal when detecting that a reactor current flowing in the reactor has become zero current; a correction signal circuit configured to detect a switching current flowing in the switching element, and generate a correction signal corresponding to the detected switching current; and an ON-period control circuit configured to control the switching element's ON period in accordance with the error signal and correction signal, from when the zero-current detector detects the zero current.

Abstract: A controller is provided for controlling a power converter that converts electrical input power of a wind turbine into electrical output power provided to a grid. The power converter includes grid-side and turbine-side converter parts. The controller comprises an input terminal for receiving a voltage reference signal associated with a predefined grid voltage and a frequency reference signal associated with a predefined grid frequency, and a network bridge controller adapted to control power conversion of the grid-side converter part. The network bridge controller includes a modulator for modulating gate drive command signals in the grid-side converter part based on a reference voltage and a reference angle derived from the voltage reference signal and the frequency reference signal. The modulator is adapted to modulate the gate drive command signals to maintain the predefined grid voltage and the predefined grid frequency in the power converter in case of failure within the grid.

Abstract: A method for controlling a power generation plant may be provided. First, an equivalent grid voltage may be estimated based on electric magnitudes measured at a connection point of the power generation plant and an equivalent model of a power grid to which the power generation plant is connected. Then, on the basis of said estimated equivalent voltage, a command indicative of reactive power to be produced by the power generation plant may be generated.

Abstract: An arrangement and a method for reactive power compensation in connection with a power transmission line. The arrangement includes at least one transformer and at least one reactive power compensator connected to the low-voltage side of the transformer and at least one adapter reactor, the adapter reactor being connected in series with the transformer so that the reactive power compensator is connected to the power transmission line via the transformer and the adapter reactor.

Abstract: A power supply is provided, including a bridge rectifier, a film capacitor and a DC-to-DC converter. The bridge rectifier rectifies an input voltage of an AC power supply to produce a full-wave rectified voltage. The film capacitor filters the full-wave rectified voltage to produce a first pulsating DC voltage. A control circuit of the DC-to-DC converter attenuates the first pulsating DC voltage to produce a second pulsating DC voltage, detects a peak value and a valley value of the second pulsating DC voltage, and produces an OCP compensation value of ?(Vx?VH)+PH accordingly, where Vx refers to the second pulsating DC voltage, VH refers to the valley value, and PH refers to the peak value. The control circuit provides an OCP function and a constant output power limitation for the DC-to-DC converter according to a compensated OCP setting value produced by adding the OCP compensation value to an OCP setting value.

Abstract: A system is disclosed which utilizes a non-pulse width modulated signal, which provides a fully rectified sinusoidal modulated DC link to a single phase AC motor to emulate a variable single phase AC power line. The system provides for reduced EMI and reduced size when compared to a controller with a PWM drive signal.

Abstract: A static synchronous compensator that generates a second axis voltage command from the difference between the DC voltage converted by a single-phase voltage AC-DC conversion circuit and a set DC voltage command. When the voltage (the voltage of an AC terminal) of the single-phase AC power system increases, since the difference between the voltage of the AC terminal and an internal electromotive force increases, the static synchronous compensator carries out a PWM control to decreases the voltage of the AC terminal side of the single-phase voltage AC-DC conversion circuit. Since the voltage of the single-phase voltage AC-DC conversion circuit becomes lower than the voltage of the single-phase AC power system, an ineffective current flows from single-phase AC power system in the static synchronous compensator so that the voltage of the single-phase AC power system can be decreased.

Abstract: A multilevel converter for controlling a multilevel converter is provided. The multilevel converter is a single phase converter with one phase leg, or a three phase converter with three phase legs, the phase legs of the three phase converter are interconnected in a star-configuration. The single phase converter with one phase leg, or each three phase converter with three phase legs, phase leg includes switching cells, and each switching cell includes semi-conductor switches arranged to selectively provide a connection to a corresponding energy storage element. The converter also includes a controller, which is provided to monitor the DC voltage of the energy storage elements, and the controller is provided to control the switching of each switching cell. The phase leg of the single phase converter, or each phase leg of the three phase converter, includes two parallel branches of switching cells, the branches being configured in a closed circuit.

Abstract: A three-phase resonant cyclo-converter comprising a power control module, wherein the power control module is arranged to develop a plurality of repeating switching periods within a cycle, the power control module further arranged to: control the length of a first switching period in the cycle to adjust the power flow, and control the relative length of two or more further switching periods in the cycle to adjust the power factor, wherein the relative length is controlled based on a cross-product of voltage and current values associated with the further switching periods.

Abstract: A low power consumption bleeder circuit is disclosed, and it is coupled to an alternating-current (AC) power source, an input filtering capacitor, and a rectifying filter. The low power consumption bleeder circuit includes a first switch component, a second switch component, and a controller. The first switch component is coupled to a first input terminal of the AC power source and a first connection terminal of the rectifying filter. The second switch component is coupled to a second input terminal of the AC power source and the first connection terminal of the rectifying filter. When the AC power source is detected to be removed, the controller controls at least one of the first switch component and the second switch component to be conductive.

Abstract: In one embodiment, a control circuit configured for an interleaved switching power supply, can include: (i) a feedback compensation signal generation circuit configured to sample an output voltage of the interleaved switching power supply, and to generate a feedback compensation signal; (ii) a first switch control circuit configured to compare a first branch voltage signal that represents an inductor current of a first voltage regulation circuit against the feedback compensation signal, where when the first branch voltage signal is consistent with the feedback compensation signal, a first switch on signal is generated to control a first main power switch of the first voltage regulation circuit to be on for a predetermined time, and then off; and (iii) a second switch control circuit configured to compare a second branch voltage signal that represents an inductor current of a second voltage regulation circuit against the feedback compensation signal.

Abstract: The present invention relates to a master-slave interleaved BCM PFC controller for controlling a PFC circuit with master and slave channels. In one embodiment, the PFC controller can include: a master channel controller that generates a master channel control signal and an inverted master channel control signal; a first phase shifter that provides a first phase shift for the master channel control signal, and generates a delayed opening signal therefrom; a second phase shifter that provides a second phase shift for the inverted master channel control signal, and generates a delayed shutdown signal therefrom; a slave channel controller that receives the delayed opening signal, the delayed shutdown signal, and a slave channel inductor current zero-crossing signal, and generates a slave channel control signal therefrom.

Abstract: A power factor correction device, and a controller and a total harmonic distortion (THD) attenuator used by same. The power factor correction device comprises a converter and a controller (320) connected to the converter to obtain an input voltage. The controller (320) comprises a THD attenuator (407) for automatic THD optimization. The converter comprises an input current detection resistor (3R8), a power switch tube (3NMOS) and an output circuit. The input current detection resistor (3R8), the power switch tube (3NMOS) and the output circuit form a feedback control loop to maintain a constant output voltage. A THD optimization function is built in the device so that the entire device is capable of being accurately offset to a designed voltage so as to be used for THD optimization, thereby dispensing with external manual adjustment and overcoming internal technical deviations while achieving high consistency.

Abstract: An adaptive dc-link voltage controlled LC coupling hybrid active power filter (LC-HAPF) for reactive power compensation includes: two dc capacitors to provide dc-link voltage; a three-phase voltage source inverter to convert dc-link voltage into compensating voltages; three coupling LC circuits to convert compensating voltages into currents; and an adaptive dc voltage controller with reactive power compensation control algorithm. The control algorithm includes: first, calculating required minimum dc-link voltage in each phase with respect to loading reactive power; three-phase required minimum dc-link voltage will be maximum one among their minimum values; compare it with predetermined voltage levels to determine final reference dc-link voltage. A dc-link voltage feedback P/PI controller outputs dc voltage reference compensating currents. An instantaneous power compensation controller outputs reactive reference compensating currents. The final reference compensating currents will be sum of them.

Abstract: There is provided a universal power supply apparatus including a power supply unit switching input power into driving power having a preset voltage level and supplying the driving power, a power recognition unit outputting a recognition voltage having a preset voltage level to an output terminal from which the power is output to recognize connection of a device, controlling a power output of the power supply unit according to a detected rated output, and recognizing disconnection of the device after the connection of the device according to a power state of the driving power of the power supply unit, and a detection unit providing a detection voltage having a preset voltage level to the output terminal.

Abstract: A four quadrant power module with lower substrate parallel power paths and upper substrate equidistant clock tree timing utilizing parallel leg construction in a captive fastener power module housing.

Abstract: A method for regulating a power line voltage includes determining a slow voltage variation by filtering an actual voltage at terminals of the voltage regulation apparatus. A fast active power variation is determined by filtering a measured active power of the DG system; wherein a first frequency of the slow voltage variation is smaller than a second frequency of the fast active power variation. The voltage regulation apparatus settings are controlled based on the slow voltage variation and a reactive power output of the DG system is controlled based on fast active power variation.

Abstract: There are provided a universal power supplying apparatus and a universal power supplying method that can be universally used for various types of devices having a variety of voltage and current levels of a driving power. The universal power supplying apparatus includes a power supplying unit that converts an input power into a driving power having a previously set voltage level and supplies the converted power, a power recognizing unit that outputs a recognized voltage having the previously set voltage level to an output terminal from which power is output to recognize connection of a device, and controls a power output of the power supplying unit according to a detected rated output, and a detecting unit that provides a detection voltage having the previously set voltage level to the output terminal.

Abstract: A bidirectional low voltage power supply (LVPS) for providing power to motor drive electronics. The bidirectional LVPS includes two simple, discrete converters. A first converter is used to provide power to an output and the second converter recycles power from the output to the power source. The first converter powers the drive electronics which drives the motor. During an operating process, the first converter shuts off and the second converter turns on to recycle power from the motor to the power source.

Abstract: A bridge-less step-up switching power supply device includes (i) a first and a second reactor having: a first and a second main winding connected to a first and a second input terminal, respectively; and a first and a second auxiliary winding magnetically coupled to the first main winding and connected to the first and second main windings, the first and second auxiliary windings having a first and a second leakage inductance, respectively; (ii) a first and a second diode connected between the first and second auxiliary windings and a first output terminal, respectively; (iii) a first capacitor connected between the first output terminal and a second output terminal; (iv) a second capacitor connected between a connection point of a third switch and a fourth switch, and the first output terminal; and (v) a controller for controlling turning on/off of first to fourth switches.

Abstract: An integrated power quality control system includes a transformer with a primary winding, a secondary winding and a compensation winding wound on a magnetic core. A power electronic converter in the system provides a reference voltage to the compensation winding for injecting a series voltage in the secondary winding of the transformer. A controller is utilized to generate a reference control voltage for the power electronic converter based on a power quality control requirement.

Abstract: A VAR dispatch system. A central control system connected to a network is configured to receive data reflecting local variations in conditions on a power grid and to transmit system control commands over the network. A plurality of VAR dispatch devices are connected to the network and to the power grid. Each VAR dispatch device is configured to detect local variations in conditions on the power grid and to transmit the data reflecting such local variations to the central control system and to receive control commands from the central control system. Each VAR dispatch device is configured to store power and to output stored power to the power grid based on local variations in conditions on the power grid. Each VAR dispatch device is further configured to output stored power to the power grid when the VAR dispatch device receives system control commands from the central control system.

Abstract: A power converter is configured to transfer energy from a photovoltaic (PV) array to a DC bus internal to the power converter. The power converter executes a modulation module to selectively connect one or more switching devices between the output of the PV array and the DC bus. The power converter is configured to operate in multiple operating modes. In one operating mode, the converter operates with a fixed modulation period and a variable on time, and in another operating mode, the converter operates with a variable modulation period and a fixed on time. The improved power converter provides highly efficient low power energy capture, improving power efficiency and enabling energy capture in low light conditions with reduced converter losses.

Abstract: A power compensator for compensating voltage at a location along a power transmission line, the compensator having a controller for controlling a voltage generated across the compensator, wherein the voltage is controlled to maintain a power transmission line voltage at a value dependent on the power transmission line location.

Abstract: A control apparatus for a power quality device comprises: a power quality analysis module, for sampling a power supply network to obtain a power quality information, and performing an analysis and computing on the sampling, so as to output an instruction information; N tracking control modules, for receiving respectively the instruction information and tracking the instruction information, so as to output N PWM control signals having a same frequency and constant phase shift therebetween, where N is a positive integer and N?2, thereby to control the power quality device; wherein the power quality analysis module and the N tracking control modules are operated based on a synchronized signal.

Abstract: A power source apparatus includes: a first series circuit that has a first rectifier element, a first switching element, and a third rectifier element; a second series circuit that has a second rectifier element, a second switching element, and a fourth rectifier element; a reactor connected between a connecting point of the first rectifier element and the first switching element and a connecting point of the second rectifier element and the second switching element; and a current detection unit having a first resistor element. The first and second switching elements are controllable based on a first zero current detection signal in accordance with a first current detected in the current detection unit, and a desired direct current voltage is fed to a load circuit.

Abstract: The disclosure relates to a passive power factor correction circuit. The passive power factor correction circuit comprises: a filtering device being used for decreasing high order harmonic of an input current; a resonance device being coupled to the filtering device for controlling operation time of the input current; and a suppression device being coupled to the resonance device for suppressing ripple of the input current.

Abstract: A power electronic converter for high/medium voltage direct current power transmission and reactive power compensation comprises a primary converter unit and an auxiliary converter unit, the primary converter unit including at least one primary converter limb including first and second DC terminals for connection in use to a DC network and an AC terminal, the or each primary converter limb defining first and second limb portions, each limb portion including at least one primary module, the or each primary module including at least one primary switching element connected to an energy storage device, the auxiliary converter unit including at least one auxiliary converter limb including at least one auxiliary module including a plurality of auxiliary switching elements connected to the energy storage device of a corresponding primary module in the first limb portion of a respective primary converter limb, the primary switching elements of the primary modules being controllable in use to switch the respective ene

Abstract: The present invention describes an electrical converter system for power supply systems, comprising at least two identical individual modules connected consecutively, characterised in that each individual module have at least four internal switching elements, at least one energy storage element and at least four connectors, wherein the connectors are paired and serve as a first and a second terminal pair; the internal switching elements of each individual module are designed in such manner that they are able to selectively connect one or both connectors of each terminal pair to the energy storage element; the cascaded connection of at least two individual modules is made in such manner that the connectors in the second terminal pair of a preceding individual module are each connected to the connectors of the first terminal pair in the respective following individual module, and at least one terminal of the first terminal pair of the first individual module of the cascaded connection and at least one terminal

Abstract: A converter for three-phase voltage has three electrically delta-connected series circuits. Each of the series circuits has at least two switching modules connected in series. A control device is connected to the switching modules and can drive the switching modules in such a way that branch currents with a fundamental frequency of the three-phase voltage and with at least one additional current harmonic flow in the series circuits. The additional current harmonic is dimensioned such that it flows in the series circuits of the converter and remains inside the converter.

Abstract: The invention relates to a method and an electrical converter of an elevator. In the method a controller of the electrical converter determines a first reactive power produced by a smoothing filter using pre-determined information on impedance of the smoothing filter. The controller may also receive information on a second reactive power from a remote node over a communication channel, the second reactive power being produced to a grid. The controller adds the first reactive power and the second reactive power to yield a total reactive power. The controller requests the electrical converter to make a plurality of compensative connections in the converter matrix to compensate the first reactive power or the total reactive power.

Abstract: A current control unit takes a deviation between a current command value and a current flowing through an inverter of a power conversion device, and controls the inverter based on the deviation. A harmonic sensing part receives input of an output current of an AC filter, and outputs a predetermined order harmonic of the input current in a direct current value form. A disturbance observer estimates the disturbance of the harmonic based on the output current and a coefficient defined as an inverse function of a transfer function from harmonic suppression current command value to filter output current detection value. A harmonic suppression control unit takes the deviation between the estimated harmonic disturbance and a disturbance command value that suppresses the disturbance, and calculates a harmonic suppression current command value. The harmonic suppression current command value is superimposed on the current command value of the current control unit.

Abstract: A first error amplification circuit amplifies a difference between a predetermined reference voltage and a first detection voltage that corresponds to the output voltage of a DC/DC converter, so as to generate a second voltage. A voltage level judgment circuit generates a third voltage having a discrete level that corresponds to the amplitude of a first voltage. A multiplying/dividing circuit multiplies the first voltage by the second voltage, and divides the resulting product by the third voltage, so as to generate a fourth voltage. A comparator compares the fourth voltage with a second detection voltage that corresponds to a current that flows through a switching transistor included in the DC/DC comparator. A driving circuit turns on the switching transistor for each predetermined period, and turns off the switching transistor according to the output of the comparator every time the second detection voltage becomes higher than the fourth voltage.

Abstract: A method of controlling a switched mode converter is disclosed in which the switching frequency varies in proportion to the square of the sine of the phase of the input AC supply. Thus the switching frequency is a maximum, and the respective on period of the switch is a minimum, when the mains voltage is a maximum. Conversely, the switching frequency is reduced, and the respective on time of the switch is increased, when the mains voltage is reduced. Such a switching method provides for a high power factor. Implementation by means of a phase locked loop and a comparator may prevent the need for complex circuitry, and may provide for direct use of a digital controller or digital signal processing through a counter output in the phase locked loop. A controller configured to operate such a method, together with an AC/DC converter embodying such a controller are also disclosed.

Abstract: A power conversion device according to embodiments includes a plurality of switch groups, a plurality of inductors, and a snubber circuit. The switch groups are respectively provided for input phases and each of the switch groups has a plurality of one-way switches that connects the corresponding input phase and output phases. The plurality of inductors are respectively connected between the input phases and the switch groups, and are coupled to one another so that current flowing through the one-way switch of one switch group moves to and continues to flow through the turned-on one-way switch of the other switch group when the one-way switch of the one switch group is turned off. The snubber circuit clamps a voltage based on the maximum voltage occurring on the plurality of inductors to a predetermined value.

Abstract: A master transistor and a slave transistor are both insulated gate bipolar transistors. A slave diode is connected in anti-parallel to the slave transistor. The master transistor is brought into conduction if a current flowing in a master reactor becomes zero, and is brought into nonconduction after elapse of a first period. The slave transistor is brought into conduction subject to elapse of a certain period after the master transistor is brought into conduction that is one of conditions for conduction of the slave transistor, and is brought into nonconduction after elapse of a second period shorter than the first period. The certain period is shorter than a period from when the master transistor is brought into conduction until when the master transistor is brought into conduction again.

Abstract: The switching power supply circuit includes a full-wave rectifier (1) which full-wave rectifies alternating power-supply voltage to output a pulsating current, and an inductor (3) connected to the full-wave rectifier (1). A level conversion circuit (20) includes a plurality of resistors connected in series, and converts inductor current detection voltage to a first current level signal and a second current level signal (S1 and S2) which are different in voltage level and which are proportional to inductor current. A continuous control setting circuit (30) generates a reference potential signal a phase of which is approximately the same as a phase of alternating input voltage from the first current level signal (S1) and compares a voltage level of the reference potential signal with a voltage level of the second current level signal (S2) to output a second set pulse (S8) that specifies timing at which a switching element (4) turns on.

Abstract: Methods and apparatus to improve power factor are disclosed. An example method includes detecting power provided to a power factor corrector; detecting power provided by the power factor corrector; and disabling the power factor corrector from correcting a power factor of a load for at least one period when the power provided by the power factor corrector is below a light-load threshold.

Abstract: A luminary dimming system having a three terminal dimming unit. The dimming unit includes a power controller and a receiver and is responsive to dimming directives received by the receiver. The power controller controls a buck switch and a freewheel switch in a manner that allows reduction of alternating current voltages. Such voltage reduction is accomplished in a manner that preserves the waveform of the source voltage and the power factor exhibited by the luminary.

Abstract: The present invention relates to an overvoltage repetition prevention circuit, a method thereof, and a power factor correction circuit including the same. The power factor correction circuit includes: an inductor receiving an input voltage and supplying an output voltage; a power switch connected to the inductor and controlling an inductor current to the inductor; and a power factor correction controller differently controlling a control structure generating a control voltage controlling a switching operation of the power switch during a predetermined overvoltage stabilization period generated in synchronization with a time that an output voltage is an overvoltage and the control structure generating the control voltage in a normal state in which the output voltage is not the overvoltage, wherein the control structure is determined according to a difference between the output voltage and a predetermined output target voltage during the overvoltage stabilization period.

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 common-core power factor correction resonant converter includes an energy-transforming circuit. The energy-transforming circuit receives an input line voltage and generates an output power. The energy-transforming circuit includes a coupling inductor and a charge-storage capacitor. The coupling inductor and the charge-storage capacitor are charged by the input line voltage in response to a control signal, so as to generate a charge-storage capacitor voltage. When the charge-storage capacitor voltage is charged to a preset voltage level, the coupling inductor and the charge-storage capacitor are discharged according to the control signal. Then, the energy in the coupling inductor and the charge-storage capacitor is transformed to the output load and provide the output voltage or current regulation.

Abstract: System and method for controlling power factor correction (PFC) for three-phase AC power conveyed via a three-phase AC power grid. Currents and voltages on the grid are monitored and used to generate waveform data enabling dynamic control of switching circuitry used in controlling one or more phase offsets between the currents and voltages.

Abstract: The present invention relates to a PFC switching power supply which can perform polarity determination and voltage detection of AC voltage without using a DC isolator such as a transformer. Included are: a power factor correction section which rectifies AC voltage inputted, outputs DC voltage to a load and corrects a power factor; an input voltage detecting section which outputs L pole detected voltage and N pole detected voltage; and a switching controller which controls the operation of the power factor correction section. An AC waveform generating section of the switching controller generates an AC waveform. The switching controller generates a drive pulse having a frequency and a duty ratio varying depending on AC waveform, whereby a predetermined level of the DC output of the power factor correction section is maintained and in addition, the power factor is corrected.

Abstract: Controlling a converter of a wind turbine is disclosed. The converter is connected to a rotor of a doubly fed asynchronous generator in order to feed electrical energy into an electric network. The converter comprises a network-side inverter, a generator-side inverter, and a controller, which outputs target values for demanded reactive power to at least one of the inverters. A reactive power target signal is determined for the portion that the network-side inverter contributes to the demanded reactive power QT, a slip signal is determined from the frequency of the network and the rotational speed of the generator, a gain value is calculated according to the slip signal, and the gain value is modified according to the reactive power target signal for the network-side inverter. The distribution of the reactive power between the two inverters is thus optimized over a wide operating range, not only at individual predetermined operating points.