Abstract: A method and a device to compensate for an asymmetrical DC bias current in a multi-phase transformer. The transformer is connected between an AC power system and an AC/DC or DC/AC high voltage converter. For each phase of the AC side of the transformer a current quantity is determined. The current quantity reflects the time dependent behavior of the magnetizing current in the phase. Time intervals in the current quantity are determined during which the current quantity reaches a positive or a negative maximum, respectively. A DC magnetizing quantity is determined from a difference between the amplitude of the positive maximum and the amplitude of the negative maximum.

Abstract: A solar power supply system includes at least one solar power conversion circuit and an inverter circuit. Each solar power conversion circuit comprises a solar module and a direct current (DC) module. The solar module converts the solar power into the DC signals. The DC module with two-stage conversion comprises a DC transformer circuit and a maximum power point tracking circuit, to boost the DC signals and adjust output power of the solar module to a maximum value. The inverter circuit converts the boosted DC signals output from the solar power conversion circuits into AC signals and combines the AC signals into the AC utility network.

Abstract: The invention relates to a direct-current high-voltage generator that comprises: current unidirectional switches (74, 76); a driver unit (130) capable of controlling the switching operation from an on-state to an off-state of a switch (74) only when a switch connected in parallel is in the on-state.

Abstract: A projection system incorporating a prism with dual total internal reflection function, to increase the performance of DLP™ projection, by offering a solution to combine 2 light paths to contribute to the brightness on the screen and at the same time rejecting flat-state and off-state light from entering the projection lens thereby enhancing contrast. In one implementation those two light paths can be collecting light from 2 different light sources which are driven in a pulsed manner with a duty cycle of approximately 50% for each of the two light sources at increased power. In a second implementation with a color sequential single DMD™ projector, while one light path passes a primary color the second light path passes the complementary secondary color. A special color transformation algorithm is proposed to transform the image input signals to make optimal use of the capabilities offered by the second implementation, and create maximum brightness and color saturation of the image.

Abstract: A driving circuit drives a switching element such that an ON-period of the switching element is shorter when a power receiving device is detected not to be placed than when the power receiving device is placed.

Abstract: The invention relates to a circuit arrangement for producing an alternating voltage or an alternating current from a unipolar direct current source having an inverter relating to a neutral conductor. The direct current source is connected to an inverter which converts the unipolar voltage of the direct current source into a bipolar intermediate circuit voltage that is stored in a buffer circuit (C1, C2) which is connected to the inverter. The inverter comprises a clocked switch (So) and an energy converting unit which is configured as a dual coil (DR1,DR2) having two windings (W1,W2) which are closely coupled to each other.

Abstract: A DC/AC converter includes: a resonant circuit including a transformer having a primary winding and a secondary winding and at least one capacitor, in which the capacitor is connected to at least one of the primary winding and secondary winding of the transformer, and an output terminal to which the load is to be connected is provided on the secondary winding side; a switching circuit connected to both ends of a direct current power supply and having a bridge configuration composed of switching elements for flowing a current through the primary winding of the transformer and the capacitor in the resonant circuit; and a control circuit that turns on/off the switching elements by a pair of drive signals, and flows a current through the load bidirectionally, thereby performs a PWM control for the current flowing through the load, wherein the control circuit includes step drive circuits which turn on the switching elements in steps, and the step drive circuits are provided so as to individually correspond to the

Abstract: A control system for controlling a multiphase power converter includes a current control module, a voltage control module and a current command selector. The current control module generates grid voltage command signals for the multiphase power converter and the voltage control module generates reference converter current command signals for the current control module. The current command selector supplies active and reactive current command signals from a supervisory controller to the current control module when the multiphase power converter is connected to the grid and supplies the reference converter current command signals to the current control module when the multiphase power converter is unconnected to the grid.

Abstract: A resonant power conversion apparatus includes a transformer T1 having a primary winding n1, a secondary winding n2, a tertiary winding n3, and a reset winding nR, a series circuit of switches S1 and S2, a capacitor Cr1 and diode D1 to the switch S1, a capacitor Cr2 and diode D2 to the switch S2, a series circuit of the winding n1 and a diode Dn1, a series circuit of the winding nR and a diode DR, a reactor Lr connected between a connection point of the switches S1 and S2 and a connection point of the windings n2 and n3, a switch S10 connected between the DC power source and the winding n2, a switch S20 connected between the DC power source and the winding n3, and a controller 10 configured to perform a zero-voltage switching operation of the switches S1 and S2.

Abstract: An active centerpoint bus balancing system which actively maintains centerpoint voltage balance of the output capacitors in a power supply having a multi-level voltage output. The centerpoint voltage balance is maintained by a novel control circuit which efficiently transfers charge from one capacitor to the other capacitor so as to maintain the same voltage on each output capacitor. The centerpoint voltage balance minimizes the effect of loading conditions. It operates even with no load, and allows severe load unbalance on the two output capacitors without creating voltage unbalance.

Abstract: A phase shift full bridge power converting system and a control method has the phase shift full bridge power converting system with a power converter, a controller, a load state detecting module, a switching controller, a switch module, a command generating module, a comparator, and a modulator module. The load state detecting module interfaces with the power converter and the switching controller. The load state detects module detects load parameter data of the power converter and switches a state at an output by using the switching controller. The controller obtains an error value between an output voltage of the comparator and a command voltage and calculates a duty cycle parameter by using the error value. According to the duty cycle parameter, a pulse control signal is generated to be outputted to a drive module for controlling the driving of the power converter.

Abstract: Systems and methods are provided for delivering current using a matrix converter in a vehicle. An electrical system comprises an AC interface, a first conversion module coupled to the AC interface, an inductive element coupled between the AC interface and the first conversion module, and a control module coupled to the first conversion module. The control module is configured to operate the first conversion module in a bidirectional operating mode to commutate current bidirectionally. When a magnitude of the current through the inductive element is greater than a first threshold value, the control module operates the conversion module in a unidirectional operating mode, wherein current is commutated unidirectionally.

Abstract: Systems, methods and devices for power generation systems are described. In particular, embodiments of the invention relate to the architecture of power conditioning systems for use with fuel cells and methods used therein. More particularly, embodiments of the present invention relate to methods and systems usable to reduce ripple currents in fuel cells.

Abstract: In order to further develop a circuit arrangement (100) as well as a method for generating at least one drive signal for at least one synchronous rectification switch of at least one flyback converter in such way that an improved and simpler thermal management can be combined with a significant cost reduction as well as with a higher efficiency, it is proposed to generate the drive signal for said synchronous rectification switch as a function of at least one oscillating signal controlling the synchronous rectification switch, of at least one constant delay time, of at least one variable delay time, and of at least one Boolean OR function.

Abstract: An apparatus and method for converting an input signal to an output AC signal in which the input voltage signal is inverted and modulated to provide an intermediate AC signal having twice the desired output frequency. The intermediate signal is then full-wave rectified and then the polarity of the rectified signal is switched every second cycle to produce the output AC signal of a desired frequency and voltage.

Abstract: A method for providing a maximum power point tracking (MPPT) process for an energy generating device is provided. The method includes coupling a local converter to the energy generating device. A determination is made regarding whether the local converter is operating at or below a maximum acceptable temperature. A determination is made regarding whether at least one current associated with the local converter is acceptable. When the local converter is determined to be operating at or below the maximum acceptable temperature and when the at least one current associated with the local converter is determined to be acceptable, the MPPT process is enabled within the local converter.

Abstract: A switching power supply includes: a transformer including primary and secondary windings; a switching circuit including first and second switching elements, first and second rectifying elements, first and second capacitive elements and a first inductor; and a rectifying/smoothing circuit. A first bridge circuit is configured by the first and second switching elements located in a diagonal arrangement and the first and second capacitive elements also located in a diagonal arrangement. The first and second rectifying elements are connected in parallel to the first and second switching elements, respectively. One of the first and second rectifying elements is in forward direction and other is in inverse direction. The first inductor is disposed on a connection line between the pair of input terminals and the first bridge circuit. The primary winding is connected to the first bridge circuit to form a H-bridge configuration. The secondary winding is disposed in the rectifying/smoothing circuit.

Abstract: A control circuit reduces switching loss by periodically stopping switching elements, and reduces the difference between the time for which positive switching elements are in on state and the time for which negative switching elements are in on state. The control circuit includes a command value signal generator generating command value signals Xu1, Xv1, and Xw1 from line voltage command value signals Xuv, Xvw, and Xwu, and includes a PWM signal generator generating PWM signals by the command value signals Xu1, Xv1, and Xw1. The command value signals Xu1, Xv1, and Xw1 are continuously at “0” for a predetermined period, and are continuously at “2” for another period. This enables reducing the difference between the period for which the PWM signals are low and the period for which they are high.

Abstract: An anti-islanding implementation that introduces a small, continuously varying phase shift pattern in the output current of an inverter. In grid-connected mode, this phase shift pattern has no impact on the frequency of the inverter's output voltage. However, when islanded, the phase shift will cause the voltage frequency to deviate from nominal. Changes in the output current phase thus correlate well with the voltage frequency, so a covariance index is used to detect an islanding configuration. When this index exceeds a threshold, a larger phase shift pattern is introduced in the output current, large enough to cause the voltage frequency to fall outside the inverter's trip protection window without compromising the inverter's power quality yet ensuring reliable tripping of the inverter.

Abstract: According to one embodiment, an apparatus includes a controller which outputs a signal for controlling ON and OFF of a switch which changes over connection between a second input terminal and the output end of a coil. The controller includes an MPPT control unit which follows a maximum power point with a period based on a zero-cross detection signal of a system voltage based on an input signal acquired by subtracting a value obtained by multiplying a droop gain simulating drooping characteristics, a control unit which outputs a direction value in such a manner that a difference between a reference output from the MPPT control unit and the input signal becomes zero, and a PWM comparator which outputs a PWM signal based on the direction value and a triangular wave voltage.

Abstract: Methods and systems for phase current reconstruction are disclosed. An example method comprises: sampling a current from a power stage comprising: three phase legs, a current sensor to measure a dc-link current, and three more current sensors configured to measure three summations of currents for the power stage, storing the sampled current into a current stack if the sampled current comes from a survived sensor and is one of the phase currents from the switching state in the state stack, and reconstructing an unknown phase current by using the previously stored currents along with the sampled current to calculate the unknown phase current. Other embodiments are described and claimed.

Abstract: A backlight driving system comprises a first inverter circuit, a second inverter circuit, a pulse width modulation (PWM) controller, a frequency regulator and a switch circuit. The pulse width modulation (PWM) controller generates an illumination signal to control the first and second inverter circuits to illuminate first and second backlight units in response to a first enable signal, and generates a maintaining signal to control the first and second inverter circuits to maintain stable lighting of the first and second backlight units in response to a first feedback signal. The frequency regulator controls the PWM controller to generate the illumination signal and the maintaining signal in response to a second enable signal and a second feedback signal, respectively. The switch circuit connects the PWM controller to the second inverter circuit in response to the second enable signal.

Abstract: A power converter includes a booster circuit, an inverter circuit, a hysteresis control circuit, and a proportional-integral control circuit. The booster circuit boosts DC power of a DC power source. The inverter circuit converts the DC power outputted from the booster circuit into AC power and outputs the AC power to a system. The hysteresis control circuit controls the inverter circuit by hysteresis control so that the AC power can be outputted to the system when an AC voltage of the system is less than a DC voltage of the power source. The proportional-integral control circuit controls the booster circuit by proportional-integral control so that the AC power can be outputted to the system when the AC voltage of the system is larger than the DC voltage of the power source.

Abstract: A method and system for controlling a power converter system with first, second, and third phase legs with respective first, second, and third associated phase currents determine direction of current flow in at least two phase legs and switch states of the power converter system in response to the current flow directions to reduce ripple current in a connected direct current (DC)-bus capacitor.

Abstract: A controller for a voltage regulator includes a hysteretic circuit that generates a hysteretic voltage output as a function of a regulated voltage and that generates a hysteretic current output as a function of an inductor current. A switch control circuit provides a quasi-continuous control output as a function of the hysteretic current output from a start time when the regulated voltage rises above a higher hysteretic voltage until a stop time when the regulated voltage falls below a lower hysteretic voltage.

Abstract: The shape of the rising and falling edges of AC output voltage pulses of a PWM frequency converter is controlled by reducing a speed of change, and a height, of the AC output voltage pulse. The PWM frequency converter rectifies the alternating voltage of a supply network into a DC voltage which is filtered. A load bridge having power semiconductor phase switches forms an AC output voltage from the DC voltage for controlling the load. An average speed of voltage change of AC output voltage pulses is set using a phase switch to control at least one power component to be conductive and non-conductive in turn for a period of at least about one microsecond to change a pulse edge of the AC output voltage pulses into at least one micropulse, the width of which is controlled to increase towards a final state of the phase switch.

Abstract: The present invention discloses a bi-direction driver IC and a method for bi-directionally driving an object. The method comprises: providing a first and a second integrated circuit (IC) chips, coupled with an object to be driven, wherein each of the first and second IC chips is capable of single-directionally driving the object; providing a reverse current path in each of the first and second IC chips; driving the object in a first direction by the first IC chip, wherein current flows through the reverse current path in the second IC chip; and driving the object in a second direction by the second IC chip, wherein current flows through the reverse current path in the first IC chip.

Abstract: A power converting apparatus includes three sets of half-bridge inverters connected between output terminals of a solar battery, each of the half-bridge inverters including two series-connected switching devices, single-phase inverters connected to individual AC output lines of the bridge inverters, and two series-connected capacitors dividing a voltage of the solar battery, wherein output terminals of the single-phase inverters are connected to individual phases of a three-phase power system. Each of the half-bridge inverters is operated to output one pulse per half cycle, each of the single-phase inverters is controlled by PWM control operation to make up for a voltage insufficiency from the system voltage, and sums of outputs of the half-bridge inverters and the single-phase inverters are output to the power system.

Abstract: In a 2-shunt system, accurate sensorless vector control can be realized without increasing shunt resistors. There is disclosed an inverter device including an inverter main circuit obtained by connecting, in a three-phase bridge-like manner, three arms formed by coupling, in series with a direct-current power source, two switching elements which perform mutually opposite on/off operations, to apply three-phase pseudo alternating-current voltages of a three-phase PWM system to an electric motor; shunt resistors connected to the direct-current power source in series with at least two of the three arms of the inverter main circuit; and a controller for detecting currents flowing through the shunt resistors in a predetermined cycle to control the on/off operations of the switching elements of the inverter main circuit based on the detected currents.

Abstract: A PWM step wave and sine wave driving device is provided. The driving device includes an ADC unit, an input processing unit, a first pulse width calculation unit, a register unit, a first output unit, a zero point detecting unit, a second pulse width calculation unit, a second output unit, and a multiplexer output unit. The driving device receives input signals, and output desired step wave or sine wave driving signals for driving an external electric device. The driving device detects a point of zero voltage of the system power supply by the zero point detecting unit. When the system power supply is abnormal, the first output unit outputs predetermined PWM step wave output signals, or the second output unit outputs predetermined PWM sine wave output signals. In such a way, the external electric device can be maintained for regular operation, so that the malfunction or breakdown thereof is prevented.

Abstract: Aspects of the invention can include capacitors which series-divide the voltage of a DC power source, an inverter circuit formed by bridge-connecting semiconductor switching elements to which diodes are antiparallel-connected, and bidirectional switches connected between a connection point of the capacitors and the AC output terminals of the inverter circuit. When the voltage of the DC power source is lower than a prescribed value, the inverter circuit can be caused to operate as an ordinary three-phase inverter, and when the voltage of the DC power source is higher than a prescribed value the inverter circuit can be caused to operate as a V-connected inverter, and when caused to operate as a V-connected inverter, a halted phase can be switched in sequence according to line voltages or output currents.

Abstract: Systems and methods for controlling a modular three-phase converter including two or more interleaved, parallel connected Voltage Source Converters (VSCs) utilizing a hybrid Space Vector Pulse Width Modulation (SVM) control scheme are provided. For the hybrid SVM control scheme, six active vectors utilized for SVM define six sectors in a space vector plane. Each sector is divided into two or more regions having corresponding optimal SVM switching sequences. In operation, a revolving reference voltage vector is sampled to provide a reference voltage vector. The SVM controller then identifies one of the regions in one of the sectors that corresponds to an angle and, in some embodiments, a magnitude of the revolving reference voltage vector and applies the corresponding optimal SVM switching sequence to the two or more interleaved, parallel connected VSCs.

Abstract: A method of controlling an isolated switching power converter that includes a transformer with a primary side and a secondary side, at least one primary switch coupled to the primary side of the transformer and at least one synchronous rectifier coupled to the secondary side of the transformer is disclosed. The method includes turning on the synchronous rectifier a first fixed time after turning on the primary switch and turning off the synchronous rectifier a second fixed time after turning off the primary switch. Power converters for operation according to this method are also disclosed, including power converters without an output inductor.

Abstract: Zero volt switching during a light load is performed in such a manner that through an ON/OFF control of switches provided for a full bridge circuit and the synchronous rectifier switches in a rectifier and smoothing circuit, a resonant peak voltage necessary for the zero voltage switching determined by the output current flowing to output terminals, a resonant inductor and a resonant capacitor capacitance is ensured so that an energy accumulated in the rectifier and smoothing circuit is returned to the full bridge circuit so as to act as equivalent as when the output current is increased and to increase the current flowing through the full bridge circuit.

Abstract: The zero-voltage converter is able to perform at extremely high power levels and bares significant benefits to all levels; system, inverter and circuitry level. Power losses are avoided by using a new developed resonant topology. EMI problems are reduced by power module integrated capacitors as well as smart selection of the terminal technology and under full utilization of the analog components and their potentials. The power module developed for this specific application is designed under a maxim of gaining highest power density as well as lowest stray inductances. High switching frequencies enable even special electro motors with extremely low leakage inductance to perform well. This is in particular beneficial for ultra high speed drives or motors with a high pole pair number. The mechanical concept of the inverter can specifically be adopted to the referring vehicle and to its available installation space. Thus, also (hybrid) electrical vehicles can be designed based on such highly innovative conception.

Abstract: A control device has a unit for preparing a pattern having first and second periods by comparing a triangular wave and a sine wave having an amplitude ratio set at each value of a modulation factor, and selecting one pattern corresponding to an instructed modulation factor, and a unit for applying a controlled voltage, set at low and high levels in response to first and second periods of the selected pattern, to a generator. The triangular wave has a cycle duration obtained by dividing the cycle duration of the generator by product of 3 and odd number, a crest having a level higher than the sine wave at a timing of each first period, and a trough having a level lower than the sine wave at a timing of each second period.

Abstract: A frequency-hopping control method is performed by a frequency-hopping control module that generates a driving signal for driving a voltage converting circuit to generate an output voltage. The method includes, generating a control signal according to a regulating signal inversely proportional to the output voltage of the voltage converting circuit. The control signal is cyclical, and each cycle of which includes an off-time having a variable duration with an inverse relation to magnitude of the regulating signal, and an on-time having a substantially fixed duration. The driving signal is generated according to the control signal and a periodic pulse signal. Therefore, the output voltage can be stabilized, and the voltage converting circuit can perform voltage conversion with reduced power loss and improved voltage conversion efficiency.

Abstract: An apparatus to deliver an alternating current (AC) power may include a controller having a processor and a memory. The apparatus may also include a plurality of power inverters in communication with the controller. Each power inverter may be configured to convert direct-current (DC) power into the (AC) power. Each of the plurality of power inverters may be configured to be controlled by the controller to generate AC power below at least one predetermined operating threshold. The plurality of power inverters may be configured to combine AC power generated by each of the plurality of power inverters, such that the combined AC power is delivered to a common AC load above the predetermined operating threshold. The apparatus may be arranged and operated according to a ratio of FMA=Fr/N, where Fr=fs/fl, fs is the switching frequency of the plurality of power inverters, fl is the frequency of the common AC load, and N is the number of power inverters of the apparatus.

Abstract: An arrangement to determine a cell capacitor voltage value of a cell of a multi-cell power converter includes the cell and a control unit. The cell itself includes four power electronic valves interconnected as a full-bridge converter having a first and a second phase leg, where each phase leg includes a series-connection of two of the four power electronic valves and where the connection point between the two power electronic valves of each phase leg is externally connectable, a cell capacitor being connected in parallel to the first and the second phase legs, and four gate units, each being connected to a corresponding one of the power electronic valves as well as to the control unit.

Abstract: A modular-based, zero-current-switched (ZCS), isolated full-bridge boost converter with multiple inputs is disclosed. Each converter module is used to match the connected input source and control the amount of power drawn from the source. The power from various sources are combined together and delivered to the load through a multiphase transformer. The input inductor of each boost-derived converter module keeps the input current constant and acts as a current source to drive the multiphase transformer through a phase-shifted-controlled full bridge converter. By connecting an auxiliary circuit across the full-bridge input in each module, the transformer leakage inductance and output capacitance of the switching devices are used to create resonant paths for facilitating zero-current-switching of all switching devices.

Abstract: A power adapter to receive at least one AC input power and transform to DC primary output power includes a power factor correction circuit to receive the AC input power and modulate to become a modulated power, an isolation voltage step-down circuit connecting to the power factor correction circuit to modulate the modulated power to a modulated lower voltage power, a switch voltage regulation circuit connecting to the isolation voltage step-down circuit to receive the modulated lower voltage power, and a voltage stabilization circuit connecting to the switch voltage regulation circuit. The switch voltage regulation circuit sets a determined output level and regulates the modulated lower voltage power to become a determined power at the determined output level. The voltage stabilization circuit modulates the determined power to become the primary output power and supplies the primary output power to a primary output end.

Abstract: A half bridge switching dc-dc converter an input dc voltage to an output dc voltage. The converter includes a switching circuit for receiving the input dc voltage and generating a periodic square wave voltage oscillating from a high value corresponding to the input dc voltage to a low value corresponding to a reference voltage. The periodic square wave voltage oscillates at a main frequency with a main duty cycle equal to about 50% when the converter operates in a steady state. The converter further includes a conversion circuit for providing the output dc voltage from the square wave voltage based on the main frequency and on the main duty cycle. The converter still further comprises a switching control circuit controlling the switching circuit for temporarily varying the main duty cycle during at least one period of the square wave after a power on of the converter.

Abstract: [Problems] To provide a non-contact power feeder that is high efficient and high power factor and has no load dependence. [Means for Solving Problems] A series capacitor Cs1 is connected to a primary winding 1 driven by an AC power supply 3 and a parallel capacitor Cp2 is connected to a secondary winding 2. The capacitance Cp is set to Cp?1/{2?f0×(x0+x2)} and the capacitance Cs converted to the primary side is set to Cs?(x0+x2)/{2?f0×(x0×x1+x1×x2+x2×x0)}, where f0 is the frequency of the power supply, x1 is a primary leakage reactance of the primary winding 1, x2 is a secondary leakage reactance of the secondary winding 2 converted to the primary side and x0 is an excitation reactance converted to the primary side. By setting Cp and Cs to the above values, the transformer of the non-contact power feeder is substantially equivalent to an ideal transformer. If it is driven by a voltage type converter, the output voltage (=load voltage) becomes substantially constant voltage regardless of the load.

Abstract: A method of controlling a brake chopper and a control arrangement, the brake chopper being connected between the positive and the negative rails of an intermediate voltage circuit feeding an inverter bridge, wherein current measurement means are arranged between a DC voltage source and the brake chopper and adapted to measure DC current flowing in the intermediate voltage circuit, which method comprises steps of forming with the inverter bridge an output voltage to a load connected to the output of the inverter bridge, determining a time instant when the DC current of the intermediate circuit is sampled, and preventing the use of the brake chopper at the determined time instant.

Abstract: A controller includes a hysteretic circuit that provides a first ON level pulse when a corresponding first negative regulated voltage rises above a respective first voltage threshold. Similarly, a second ON level pulse is provided when a corresponding second positive regulated voltage falls below a respective second voltage threshold. The hysteretic circuit provides an OFF level pulse when one of first and second switch currents increases above a current threshold. A switch control circuit receives the first and second ON level pulses and the OFF level pulse, and provides first and second switch control outputs to separately regulate the first and second regulated voltages.

Abstract: A circuit for generating a high voltage alternating current to drive a load has a current source having a first terminal and a second terminal. The circuit further has an output terminal and a circuit ground terminal. A first switch will conduct between the first terminal of the current source and the circuit ground terminal when the first switch is closed. A second switch will conduct between the first terminal of the current source and the output terminal when the second switch is closed. A third switch will conduct between the second terminal of the current source and the circuit ground terminal when the third switch is closed. A fourth switch will conduct between the second terminal of the current source and the output terminal when the fourth switch is closed. A load is coupled to the output terminal and the circuit ground terminal.

Abstract: A three-phase inverter circuit including a DC portion including capacitors connected between output terminals of a solar battery and single-phase inverters connected in series with AC output lines of the three-phase inverter circuit that together constitute an inverter section, the inverter section being connected to a three-phase power system. The three-phase inverter circuit outputs a reverse-polarity voltage pulse during a period within each of basic voltage pulses of which pulsewidth corresponds to a half cycle every half cycle of a system voltage. A power burden born by the individual single-phase inverters in each half cycle is made approximately zero and the individual single-phase inverters make a correction for subtracting a common voltage from target output voltages of individual phases during the period when the reverse-polarity voltage pulse is generated.

Abstract: A current controlled power converter includes a converting part configured to convert a three-phase ac voltage into a dc voltage or converts a dc voltage into a three-phase ac voltage, ac side current detection portions configured to detect an ac side current of the converting part, dc side current detection portions configured to detect a dc side current of the converting part, and a control section configured to control the converting part by pulse-width modulation using a spatial vector modulation method based on the ac side current detected by the ac side current detection portions and the dc side current detected by the dc side current detection portions. The control section corrects an amplitude error of the ac side current detected by the ac side current detection portions, and an offset error of the ac side current detected by the ac side current detection portions.

Abstract: Method for operating an ac/ac converter circuit for a high-frequency-link converter. The ac/ac converter circuit converts an ac input voltage to an ac output voltage. When the ac input voltage is zero, each of a pair of switches for both first and second arms are caused to be on. Current flows through the first arm along a first direction and through the second arm along a second, opposite direction. Next, when the ac input voltage is zero, a selected switch in the second arm is caused to be turned off. The position of the switches can be maintained as the ac input voltage transitions to a dc level, reaches the dc level, approaches zero, and again reaches zero. When the ac input voltage again reaches zero, the selected switch for the second arm is caused to be turned on.

Abstract: Various embodiments of the present invention provide voltage converters and methods for using such. As one example, a voltage converter is disclosed that includes a transformer, an operational detector, and a controllable oscillator. The transformer includes a first winding and a second winding, and the operational detector provides an electrical output corresponding to an operational characteristic of the transformer. The controllable oscillator provides a clock output with a frequency corresponding to the electrical output. This clock output at least in part controls application of a voltage input to the first winding.