Abstract: An over-voltage protection circuit and methods of operation are provided. In one embodiment, a method includes monitoring a voltage at an output of a rectifier, a voltage at an output of a voltage regulator, or a combination thereof. The method further includes determining the over-voltage condition based on the monitoring; and in response to determining the over-voltage condition, regulating the voltage at the output of the rectifier in accordance with a voltage difference between the voltage at the output of the rectifier and the voltage at the output of the voltage regulator.

Abstract: A negative feedback closed loop circuit composed of an operational amplifier, a main switch, and a current sense resistor is applied to limit the current to a pre-defined threshold whenever there is an overload or short circuit condition is the circuit. A timing circuit composed of resistors and a capacitor is used to provide timing of turning off the circuit. The timing circuit is always charged from the same voltage and started from the same moment of main switching entering into current limit mode. The voltage reference is set by a voltage divider. The timing capacitor voltage and the voltage reference is compared in a comparator. Since both the amplifier circuit and the comparator circuit are temperature independent, the current limiting point and the time delay to turn off the switch are also both independent of temperature.

Abstract: A phase-redundant voltage regulator apparatus includes groups of regulator phases, each having a multi-phase controller (MPC) connected to each regulator phase. The MPC transfers, to control logic, phase fault signals and a shared current (ISHARE) phase control signal received from the regulator phases of a phase group. Spare regulator phases include output ORing devices to limit current flow into spare regulator phase outputs. Output switching devices are configured to electrically couple spare regulator phase outputs to a common regulator output. Control logic is connected to the phase groups MPC and asserts phase enable signals to, transfers ISHARE phase control signals to, and receives phase fault signals from the spare regulator phases. The control logic electrically interconnects a spare regulator phase to a phase group including a failed regulator phase in response to receiving a phase fault signal from an MPC.

Abstract: Systems and methods for protecting switching devices in a power converter in doubly fed induction generator power systems are provided. A DFIG system can include a DFIG generator and a power converter comprising a line side converter and a rotor side converter connected by a DC bus. Each of the line side converter and rotor side converter can include a plurality of bridge circuits. Each bridge circuit can include a plurality of switching devices. A method can include monitoring, by a control device, a voltage of the DC bus of the power converter. The method can further include implementing, by the control device, a switching device protection measure based at least in part on the voltage of the DC bus of the power converter. The switching device protection measure can be operable to protect the switching devices by operating the switching devices within a safe operating area.

Abstract: An alternating current power generation system including an alternating current generator comprising an exciter, a brushless permanent magnet generator voltage source configured to generate a first voltage at a first frequency, a second voltage source configured to generate a second voltage at a second frequency, and a coil. Further, the brushless permanent magnet generator voltage source provides the first voltage as a supplemental voltage supply combined with the second voltage source at the coil to generate a constant exciter field received by the exciter of the alternating current generator.

Abstract: A power supply unit (1) that is to be connected to different types of power supply networks includes an input (2) to receive AC power from the power supply network and an output (3) for providing power to an electrical device. The electrical device may for example be a computer, a telecom infrastructure device, inductive cooking/heating systems or an on-board charger of an electrical automotive vehicle. The power supply unit (1) includes at least two converters (4) that are connected between the inputs (2) and the output (3) and it further includes a controllable switching arrangement (5). The switching arrangement (5) includes a number of controllable switches (6) to controllably connect the converters (4) in different configurations to the input (2) and therefore also controllably to different supply lines of the power supply network.

Abstract: A transformer tap-changing circuit comprises an apparatus that includes a transformer comprising a secondary winding configured to inductively couple to a primary winding when a current is passed through the primary winding from an energy source, a first rectifier coupled to the secondary winding and configured to rectify a first AC voltage from the secondary winding into a first DC voltage, and a second rectifier coupled to the secondary winding and configured to rectify a second AC voltage from the secondary winding into a second DC voltage. The apparatus also includes a DC bus coupled to the first and second rectifiers and configured to receive the first and second DC voltages therefrom, wherein the first AC voltage is higher than the second AC voltage, and wherein the first DC voltage is higher than the second DC voltage.

Abstract: A gate firing phase shift delay line technique is described for use in DC motor drive systems and is easily adaptable for controlling a plurality of electronically coupled power modules. A drive regulator is configured to produce a master gate firing timing signal for controlling the gate firing pattern of switching devices for a first power module. One or more delay blocks are configured to generate slave gate firing timing signals that are phase locked and identical but delayed in time with respect to the master signal. Each additional delay block is coupled to an additional power module having a set of switching devices controllable by the slave signals. The current output of each power module is summed via summing circuitry to deliver an output suitable to drive motors or other electrical loads in high power applications. The power modules can also be connected in series to combine (sum) the voltages for delivery to an electrical load.

Abstract: A switching voltage regulator including a comparison module configured to receive a reference voltage and a feedback voltage and to generate a comparison signal corresponding to a difference between the reference voltage and the feedback voltage, an offset module configured to generate an offset signal based on a number of active phases of the voltage regulator, an adder configured to generate a control signal based on the comparison signal and the offset signal, a plurality of pulse-width-modulated (PWM) power stages, and a control module configured to control the plurality of PWM power stages based at least in part on the control signal generated by the adder.

Abstract: A power conversion device connected with a three-phase power system through a transformer, including unit converters cascade-connected so that reactors are unnecessary, and volume and weight are reduced. The secondary winding of the transformer is an open winding having six terminals. A first converter group, includes a circuit which has three converter arms, which are star-connected, connected to three of the terminals of the secondary winding. A second converter group, having three different converter arms which are star-connected, is connected to three other terminals of the secondary winding. A neutral point (the point where the star connection is made) of the first converter group, and a neutral point of the second converter group are made to be the output terminals of the power conversion device.

Abstract: A method is described for controlling a plurality of parallel-connected power converters 20a, 20b, each of which operates in accordance with a pulse width modulation (PWM) strategy defined by an independent voltage carrier signal and an independently controllable modulating sinusoidal voltage signal which are used to generate a PWM command signal for each PWM strategy. The voltage carrier signals of the PWM strategies have the same switching period and desynchronisation of the PWM command signals causes an unwanted circulating current to flow between the power converters 20a, 20b. The method thus comprises providing the independently controllable modulating sinusoidal voltage signal of the PWM strategy of at least one of the plurality of power converters 20a, 20b with a dc voltage offset to modify the PWM command signal of the at least one power converter and thereby increase the synchronisation of the PWM command signals so that the magnitude of any unwanted circulating current is reduced.

Abstract: A bridgeless PFC (power factor correction) converter with improved efficiency is disclosed. The bridgeless PFC converter comprises: a first input terminal and a second input terminal configured to receive an input AC signal; an output terminal; an inductor set comprising N inductors, wherein a first terminal of each inductor is coupled to the first input terminal; and an output stage comprising (N+1) switching circuits coupled between the output terminal and a ground node.

Abstract: A VSC converter includes in each valve one first semiconductor device of turn-off type with a voltage blocking capacity rating of a first, high level and connected in parallel therewith a series connection of a plurality of second semiconductor devices of turn-off type with a voltage blocking capacity rating of a second, lower level. A control arrangement of the converter is configured to switch a said valve into a conducting state starting from a forward biased blocking state of the valve by controlling the second semiconductor devices to be turned on and then the first semiconductor devices to be turned on with a delay, and at the end of the conducting state to turn off the first semiconductor device in advance of turning the second semiconductor devices off.

Abstract: An active rectifier system that rectifies power supplied to an electrical device includes a load detector to determine an electrical load applied on the active rectifier system by the electrical device. A plurality of active rectifier modules are configured to convert an input alternating current (AC) power into an output direct current (DC) power. Each active rectifier module is operable according to a respective switching signal. A control module is configured to selectively output the switching signal to at least one selected active rectifier module among the plurality of active rectifier modules based on the electrical load.

Abstract: A converter includes a converter bridge (101) adapted to transfer electrical energy between the AC terminal (102) and the DC terminal (103) of the converter. The converter also includes electrical paths bypassing the converter bridge for conducting overvoltage transients occurring in the AC terminal around the converter bridge to the DC terminal. Each electrical path includes a unidirectionally conductive semiconductor component (104a, 104b, 104c), such as a diode, and a voltage-limiting component (105) for which the ratio of voltage change to current change is small when the voltage of the voltage-limiting component is greater than a predetermined threshold voltage. Because of the overvoltage protection thus achieved, AC chokes can be omitted from the AC terminal or at least they can be designed smaller, reducing the load-dependent voltage drop of the DC terminal.

Abstract: A power conversion apparatus according to the present invention includes a plurality of PWM converters (2 and 3) that are connected in parallel and convert power supplied from a common three-phase AC power supply (1) into DC power and, and supply the DC power to a common load (6) and a plurality of short-circuit prevention reactors (10 and 11) that are connected to an output side of a part or all of the PWM converters (2 and 3) and, when a deviation occurs in operation timings of switching elements of a same phase in the respective PWM converters, reduce a short-circuit current flowing between PWM converters with mismatched operation timings.

Abstract: A power supply device includes two buck converters, having a coupling inductor Lo composed of two mutually-coupled inductors L1, L2, and a output capacitor Co, wherein of the two buck converters, a first buck converter is operated during a positive half-cycle period of an AC input voltage, and a second buck converter is operated during a negative half-cycle period of the AC input voltage, to obtain a DC output voltage at both ends of the output capacitor Co from the AC input voltage, is provided. Herewith, is provided the power-supply device using the buck converter, which can be reduced in the number of components and produced in a low cost without a diode bridge.

Abstract: A Graëtz-bridge converter-rectifier in which at least one rectifier arm situated between a single AC terminal and a single DC terminal includes multiple unidirectional electronic components connected in parallel and connected on one side to the DC terminal by means of a conductive component set and on the other side to the AC terminal. The invention is characterized in that the component set for at least one rectifier arm includes a plurality of separate component busbars each having at least one end connected to the DC terminal, the unidirectional components being divided between the component busbars into as many component sets connected in parallel as there are component busbars.

Abstract: A power rectifying circuit for an electric current signal supplied by an alternating power source, which includes: two separate switching assemblies adapted to be connected to a power terminal of the source, wherein at least one switching assembly includes a plurality of boost cells in cascade, each boost cell including a diode, a switch mechanism and a capacitor, the capacitors of the two terminal boost cells of the switching assemblies having one terminal in common. The circuit may include two assemblies of boost cells, and can be used in electric systems onboard aircrafts.

Abstract: Switches perform switching at a timing when a first phase voltage and a second phase voltage outputted from a three-phase voltage source have a phase difference of 90°. Then, a three-phase/two-phase conversion inductor outputs a pair of AC currents, and a rectification and a single-phase pulse-width modulation are performed on each of AC currents. Modulated currents obtained as a result of the rectification and the single-phase pulse-width modulation are synthesized, to generate an output current, which is supplied to a circuit in which a capacitor and a load are connected in parallel with each other.

Abstract: A multi-phase converter of one of the embodiments includes: a plurality of AC/DC converters which are connected in parallel to each other, wherein each of the plurality of AC/DC converters includes a power factor correction circuit and a DC/DC converter that is connected in series to the power factor correction circuit and that receives an output from the power factor correction circuit, and the power factor correction circuit includes an output voltage adjusting circuit that adjusts an output voltage from the power factor correction circuit.

Abstract: A power factor correction (PFC) system includes an adjustment module, a compensation module, and a duty cycle control module. The adjustment module generates N time advances based on N predetermined time advances and (N?1) time advance adjustments, wherein N is an integer greater than zero. The compensation module generates N compensated versions of an input alternating current (AC) line signal by predicting ahead of the input AC line signal using a gradient of a sinusoidal reference signal and the N time advances, respectively, wherein the sinusoidal reference signal is synchronized with the input AC line signal in phase and frequency. The duty cycle control module generates PFC duty cycles based on the N compensated versions of the input AC line signal.

Abstract: Embodiments of the present invention relate to a low-output voltage converter, delivering voltage power less than 1 VDC, utilizing distributed secondary circuits. In one embodiment of the present invention, there is provided a voltage converter comprises a primary circuit for receiving an input voltage, comprising a plurality of primary windings arranged in series, a plurality of secondary circuits, each comprising a secondary winding for aligning with a primary winding to form a transformer, and each of the secondary circuits arranged in parallel, and an output for providing an output voltage down to, or less than 1 VDC.

Abstract: A multi-output DC-to-DC conversion apparatus with a voltage-stabilizing function includes a center-tapped main transformer, a semiconductor component group, and a triggering controller. The DC-to-DC conversion apparatus provides at least two output voltages which are a main output voltage and an auxiliary output voltage, respectively. The auxiliary output voltage is functioned as an input voltage of a buck converter; and, as a result, the auxiliary output voltage can be adjusted to obtain a lower variable DC voltage. The triggering controller is used to stabilize the main output voltage and the auxiliary output voltage. Therefore, the main transformer provides one or two secondary windings to step down the auxiliary output voltage so as to increase efficiency of the buck converter.

Abstract: A circuit includes an antenna terminal for generating a current through electromagnetic induction. The circuit also includes a rectifier for receiving the current and generating a rectified power supply voltage. In addition, the circuit includes a voltage clamp for sinking at least some of the current from the antenna terminal based on the rectified power supply voltage from the rectifier. The voltage clamp could include a control circuit (such as an N-channel transistor and a resistor) for controlling the sinking of at least some of the current from the antenna terminal. The voltage clamp could also include a sink circuit (such as an N-channel transistor) for sinking at least some of the current from the antenna terminal. The voltage clamp could further include a sink control circuit (such as a P-channel transistor and a resistor) for activating and deactivating the sink circuit based on operation of the control circuit.

Abstract: A regulated power supply apparatus and method are provided. The apparatus includes a converter circuit for generating a regulated voltage signal. The converter circuit includes a first switching circuit and a second switching circuit both coupled with an output circuit. A first and a second transformer include a first and a second secondary, which are coupled with each other in series or alternatively, coupled with each other in parallel. An input rectifier circuit is coupled with the first and the second switching circuit. The input rectifier circuit is configured for receiving an AC input voltage and for generating a rectified voltage. The input rectifier circuit includes controlled switches and a first and second configuration of a bridge rectifier that couples the first and second switching circuits in series or parallel depending if the AC input power signal is “high-line” or “low-line.” A controller circuit is provided for enabling either the first configuration or the second configuration.

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: A power source apparatus has a power source unit (AC, DB, Ci), a pair of reactors L1a and L1b each having a winding, and a controller 10 to accumulate energy of the power source unit in the pair of reactors and control the accumulated energy by turning on/off a switching element Q1. The windings of the pair of reactors are arranged so that the windings face each other and the polarities of magnetic flux from the windings are opposite to each other.

Abstract: A multi-phase (N) power supply is presented having current shared power factor correction. This includes N input rectifier filters each receiving a respective different one of an N phase AC input signal and providing therefrom one of N rectified signals. N single phase power factor correction pre-regulators each receive a respective different one of the rectified signals and provide therefrom a regulated signal. A current sharing N way to single way multiplexing switch network receives the N regulated signals and provides therefrom a single output signal.

Abstract: A multiple-output switching power source apparatus includes a control circuit to adjust a time for applying a DC voltage to a primary winding of a transformer by turning on/off a switching element Q1, a first rectifying-smoothing circuit for a first secondary winding of the transformer, a second rectifying-smoothing circuit for a switching element Q2 to provide a second output voltage connected to an output terminal of the first rectifying-smoothing circuit through the switching element Q2, a third rectifying-smoothing circuit for a second secondary winding of the transformer and provide a third output voltage, a first end of the second secondary winding of the transformer being connected to the switching element Q2, and a control circuit 13 to adjust an ON/OFF time of the switching element Q2 according to the voltage of the first secondary winding of the transformer, the second output voltage, and the third output voltage.

Abstract: A full-wave rectifying device includes a first rectification module and a second rectification module. The first rectification module includes one or a plurality of first rectification units. The second rectification module includes one or a plurality of second rectification units. In each of a plurality of transistors, the substrate is connected to the source so as to reduce the body effect of the rectifying circuit efficiently and enable generation of a dc voltage signal through rectification by a plurality of capacitors. A multistage rectifying circuit architecture including a plurality of first rectification units and second rectification units is provided, so as to reduce the body effect of transistors of a conventional rectifier and significantly stabilize the voltage output level, thereby allowing the rectifying circuit to generate a dc voltage level of designed value.

Abstract: A slope compensation method and circuit for a peak current control mode power converter circuit is provided. Since the power converter circuit has a synchronous signal of a driven signal of enabling the first primary switch and the second primary switch, a triangular wave signal is generated. The driven signals of the first and second primary switches determine the ramp up time of the triangular wave signal. The triangular wave signal is added to one of the output DC voltage feedback signal of the corresponding power converter circuit that are used to compare with a current peak value of the voltage feedback signals. Therefore, a high level triangular wave DC voltage feedback signal that is higher than the DC voltage feedback signal is formed, and the switching noises do not effect comparing result of a PWM controller of the power converter circuit.

Abstract: An interleaved power factor correction (PFC) circuit includes phase management to control shedding and adding of channels. The channels may be voltage (e.g., boost) converters connected in parallel. The interleaved PFC circuit can have a first channel and a second channel that operate out of phase of each other to provide input power to a load. In a two phase interleaved PFC circuit, the first and second channels operate 180 degrees out of phase. A channel may be shed or added depending on load conditions. The phase management can be configured to add or remove a channel only when the AC line input to the interleaved PFC circuit crosses zero.

Abstract: There is provided a bridgeless power factor correction circuit that corrects a power factor by complementarily switching two switches according to phase of input power without using rectifier bridge diodes. A bridgeless power factor correction circuit according to an aspect of the invention may include: a switching unit having a plurality of switches and alternately switching input AC power; a stabilizing unit rectifying and smoothing the power switched by the switching unit; and a control unit controlling an alternate switching operation between the plurality of switches according to phases of the input power.

Abstract: A method and system for managing a dual rectifier uninterruptable power supply, comprising activating each of said rectifiers to provide an output DC voltage, monitoring a level of operation of the uninterruptable power supply and deactivating a selected one of said dual rectifiers when a level of operation of said two activate rectifiers is less than a first predetermined level of operation.

Abstract: The present invention provides a method of improving efficiency in a full load region in a PFC power source of an active filter method by controlling a switch circuit of the PFC power source in association with an output power of the PFC power source. A pair of two switches controlling charging/discharging an inductor is provided. A MOSFET switch having a small current capacity is used as one of the switches, and an IGBT switch of a large current capacity is used as the other switch. When an output of a voltage dividing circuit for dividing voltage of an output terminal of the PFC power source is smaller than a threshold voltage, only the MOSFET switch is operated. When the output exceeds a threshold voltage, the IGBT switch is also operated.

Abstract: A resonant converter for improving synchronous rectification control is provided. The resonant converter obtains an input power, and through a switch unit, the period of the input power to be transmitted to a resonant circuit can be modified. The resonant converter further includes two transformers electrically connected to the resonant circuit, two synchronous controllers electrically connected to the primary sides of two transformers respectively, and two synchronous rectifiers electrically connected to the secondary sides of two transformers. The input power modified by the resonant circuit is obtained by the primary sides of two transformers, and two induced power are respectively produced at the secondary sides. Then, through sensing the polarity variation of the voltage, the two synchronous controllers individually provide a synchronous driving signal.

Abstract: A power supplying apparatus includes a conversion device to convert direct current (DC) power from a battery set into alternating current (AC) power. A current transformer arrangement may generate a DC charging signal based on the AC power and provide the DC charging signal to the battery set. The current transformer may include a plurality of current transformers.

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: A circuit arrangement for wirelessly exchanging data with a reader device, including an antenna for converting electromagnetic radiation into an antenna voltage, an analogue circuit for demodulating an information signal based on the antenna voltage, and a digital circuit for processing of the information signal and for receiving power from the analogue circuit. The circuit arrangement also includes a decoupling circuit, which is interconnected between the analogue circuit and the digital circuit and provides a decoupling of both circuits.

Abstract: In a power converting apparatus in which two three-phase converters (1), (2) are operated parallel to one another, the three-phase converters (1), (2) are controlled by using d- and q-axis voltage commands. DC current sensors (26), (27) detect individual output DC currents (26a), (27a) of the three-phase converters (1), (2), and a d-axis voltage command vdr for each of the three-phase converters (1), (2) is corrected in a manner that reduces a difference between the output DC currents (26a), (27a). In this way, an output imbalance between the two three-phase converters (1), (2) is corrected while decreasing limitations on arrangement of the DC current sensors (26), (27).

Abstract: A power generation system for supplying a resultant output voltage is provided. The system comprises a power converter system. The power converter system comprises at least two power converter bridges, each configured for switching at a low frequency and generating a corresponding converter output voltage including a fundamental voltage component and harmonic components, and at least two power converter transformers. Each power converter bridge is coupled to a primary winding of a corresponding power converter transformer and a secondary winding of one power converter transformer is coupled to a secondary winding of a second power converter transformer. The resultant output voltage comprises a sum of the fundamental voltage components of each converter output voltage.

Abstract: A circuit includes an input and an output, and an electronic light generator drive portion that is coupled to the input and drives the output. In one configuration, the circuit includes a further portion that is coupled to the input and that tunes a resonance at the input to a first frequency, the further portion having an additional portion with a resonance that is tuned to a second frequency different from the first frequency, and that effects damping of the first frequency at the input. In a different configuration, the drive portion includes an electronic switch coupled to the output of the circuit, and a further portion coupled to the input and having a phase tracking portion, the phase tracking portion tracking a phase of a signal at the input and producing a control signal that is used to control the electronic switch.

Abstract: The configurations of a bridgeless PFC circuit system and a controlling method thereof are provided. The proposed system includes a bridgeless PFC circuit having a first and a second input terminals, a first switch having a first terminal, a first inductor having a first terminal coupled to the first input terminal and a second terminal coupled to the first terminal of the first switch, and a second inductor having a first terminal coupled to the second input terminal, a first auxiliary winding coupled to the first inductor and generating a first sensing signal, and a second auxiliary winding coupled to the second inductor and generating a second sensing signal, wherein the first and the second sensing signals are used to generate an inductor current sensing signal controlling the switching of the first switch accordingly.

Abstract: A variable speed drive with a converter that is controllable to precharge a DC link is provided. The variable speed drive also includes an inverter. The converter converts a fixed line frequency, fixed line voltage AC power from an AC power source into DC power. The DC link filters the DC power from the converter. Finally, the inverter is connected in parallel with the DC link and converts the DC power from the DC link into a variable frequency, variable voltage AC power. The converter includes a plurality of pairs of power switches, wherein each pair of power switches includes a reverse blocking power switch arrangement connected in anti-parallel to another reverse blocking power switch arrangement. Alternatively, each pair of power switches includes a reverse blocking power switch connected in anti-parallel with a silicon carbide controlled rectifier.

Abstract: AC/DC rectifiers are vital elements in industry. Their uses include HVdc electric energy transmission, uninterruptible power supplies (UPS), electrochemical plants, railway systems, variable speed induction motors, telephone plants, etc. Regrettably, currents IA, IB and IC on the primary side of the transformer feeding the rectifier are distorted, which is penalized worldwide. Conventionally, this distortion is reduced through an apparatus connected either on the primary or secondary side of the transformer. The proposed apparatus, however, is connected on the DC side of the rectifier. It is demonstrated in a laboratory prototype that this apparatus achieves notably low distortion levels (ideally zero) in currents IA, IB and IC, at low cost and with a simple and robust control system, which is capable of handling rapid load variations. It can also be repaired on line without the need to disconnect the system.

Abstract: A universal energy supply system for at least one electrical consumer comprises at least one AC voltage source and a cable connection connecting the source with the electrical consumer, wherein an AC/DC converting means is assigned to the AC voltage source for converting the AC voltage into DC voltage which DC voltage can be supplied to the electrical consumer via the cable connection. To improve such a universal energy supply system in that with small constructional efforts and with low costs, the energy supply to an electrical consumer is guaranteed also over great distances and the corresponding voltage supply is stabilized, the efficiency being relatively high at the same time and the system being redundant, the AC/DC conversion means comprises a number of AC/DC converting units which are connected in parallel with the AC voltage source on the input side and are serially connected to the electric consumer on the output side, each converting unit being constructed as a blocked switch mode power supply.

Abstract: An 18n-pulse rectifier for AC drive systems having a separate DC bus for each output phase is described, where n=any positive integer. The rectifier uses three separate phase rectifiers, one for each output phase of a transformer, each comprised of n six-pulse diode bridges connected in series or parallel. Each phase rectifier may be supplied with n unique sets of phase inputs from a transformer secondary winding. In some configurations, the n sets of inputs provided to each rectifier are separated by 60/n degrees of phase (when n is greater than 1), while the corresponding inputs to neighboring rectifiers are separated by 20/n degrees of phase. In a 36-pulse example, the phase offsets for the inputs provided to the rectifiers may be ?25° and +5° from the transformer primary winding (for the first rectifier), ?15° and +15° from the primary winding (for the second rectifier) and ?5° and +25° from the primary winding (for the third rectifier).

Abstract: For use in a power converter having parallel power trains, a circuit for, and method of, reducing voltage spikes due to magnetizing current imbalances in the power trains and a power converter incorporating the circuit or the method. In one embodiment, the circuit includes: (1) a conductive bypass path coupling nodes between transformer secondary windings and inductors in each of the power trains and configured to provide an alternative path to redirect magnetizing current imbalances from the inductors and (2) a capacitor located in the conductive bypass path.

Abstract: An object of the present invention is to provide a photovoltaic power generation system which is capable of achieving system linkage of a plurality of solar cell strings having different output voltages to a commercial electric power system with ease, and which enables efficient use of the maximum output electric power. It is a photovoltaic power generation system characterized by disposing voltage regulating means that regulates a DC voltage outputted from non-standard solar cell string between a standard solar cell string and electric power converting means, and regulating an output voltage of the non-standard solar cell string to the side of an output voltage of the standard solar cell string by the use of the voltage regulating means.