Abstract: An electric power converter according to an embodiment includes a switching unit, a controller, and a second bidirectional switch. The switching unit includes a plurality of first bidirectional switches disposed between a DC power source and an AC load or between a DC load and an AC power source. The controller controls the switching unit to perform power conversion between DC power and AC power. When turning off the second bidirectional switch disposed on a path between one pole of the DC power source or the DC load and the switching unit, the controller turns on the first bidirectional switch connected between the other pole of the DC power source and the AC load or between the other pole of the DC load and the AC power source.

Abstract: A power converting apparatus according to an embodiment includes a controller that controls a power converter. The controller includes a first signal generator which generates switch drive signals for AC-to-DC conversion, a second signal generator which generates switch drive signals for DC-to-AC conversion, and a drive signal generator which generates, in accordance with the switch drive signals for AC-to-DC conversion and the switch drive signals for DC-to-AC conversion, switch drive signals for controlling the power converter. The first signal generator and the second signal generator operate in synchronization with each other.

Abstract: When first drive signals are driving signals for applying a short-circuit mode for turning on a plurality of switching elements of the same output phase, the current source power conversion apparatus according to one embodiment generates second drive signals for applying the short-circuit mode to an output phase having the smallest absolute value of a phase voltage, and switches the first drive signals to the second drive signals.

Abstract: An alternating-current/direct-current converter includes a rectifier, a reactor, a capacitor, and a switching rectifier. The rectifier is configured to rectify alternating-current voltage output from an alternating-current power source, thereby converting the alternating-current voltage into direct-current voltage, and to output the direct-current voltage. The capacitor includes terminals. The switching rectifier is coupled to the AC power source and switchable to output the direct-current voltage to the capacitor.

Abstract: A power converter according to an embodiment includes a power conversion unit and a controller. The power conversion unit includes a plurality of first bidirectional switches that are disposed between a plurality of DC side terminals and a plurality of AC side terminals, and a second bidirectional switch and a reactor that are disposed between the AC side terminals. The controller keeps the second bidirectional switch ON in any one or both of a free-wheeling mode in a step-down power conversion from DC power into AC power, and an energy storing mode in which electric energy is stored in the reactor in a step-up power conversion from the AC power to the DC power.

Abstract: A current source inverter device according to an embodiment includes an inverter that supplies AC power to a number n (integer of 1 or greater) of AC motors each having a number m (integer of 2 or greater) of windings per phase; and a controller that controls the inverter and AC motor. The inverter includes a switching unit, in which a number n×m+1 of switching elements per phase are connected in series, and a number n×m of nodes among the switching elements are respectively connected with a number n×m of different windings with the same phase among the windings of the number n of the AC motors. The controller includes a mode selector that selects at least one winding as a supply target of the AC power from the number n×m of the windings based on a rotation speed of the AC motor.

Abstract: A current-source power converting apparatus according to an embodiment includes an inverter and a drive controller. The inverter includes, in every output phase, a plurality of switching elements that are serially connected between the positive pole and the negative pole of a direct current source. The drive controller controls the inverter in accordance with a current command in an output mode of controlling the switching elements of different output phases for supplying current between the output phases and a short circuit mode of controlling the switching elements of the same output phase. An output phase in which the drive controller executes the short circuit mode is an output phase whose phase voltage or phase current has the minimum absolute value.

Abstract: An electric power converter according to an embodiment includes a switching unit, a controller, and a second bidirectional switch. The switching unit includes a plurality of first bidirectional switches disposed between a DC power source and an AC load or between a DC load and an AC power source. The controller controls the switching unit to perform power conversion between DC power and AC power. When turning off the second bidirectional switch disposed on a path between one pole of the DC power source or the DC load and the switching unit, the controller turns on the first bidirectional switch connected between the other pole of the DC power source and the AC load or between the other pole of the DC load and the AC power source.

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 current-source power converting apparatus in an embodiment includes a current-reference generating unit, a polarity determining unit, a PWM-pulse-signal generating unit, and a drive-signal generating unit. The current-reference generating unit outputs a phase current reference and a line-to-line current reference. The polarity determining unit determines a polarity of the phase current reference. The PWM-pulse-signal generating unit generates a PWM pulse signal by comparing the line-to-line current reference and a carrier signal. The drive-signal generating unit generates a drive signal that drives each of a plurality of switching elements, based on the PWM pulse signal and a polarity of the phase current reference.

Abstract: This current converter is formed to short-circuit input-side terminals of a plurality of power conversion portions, to parallelly connect output-side terminals of the plurality of power conversion portions with each other and to couple inductors provided on the plurality of power conversion portions respectively with each other, to be capable of performing an operation of moving currents between windings of the coupled inductors on the basis of ON-/OFF-states of pluralities of one-way switches.

Abstract: A three-level inverter includes a set of series-connected capacitors connected in parallel to a direct-current power supply; two arms connected in parallel to an output of the direct-current power supply and each having an alternating-current output terminal; and a control section having a neutral voltage controller determining a three-phase voltage correction command based on a neutral voltage and voltage of the direct-current power supply, having a coordinate converter converting the three-phase voltage correction command to a voltage correction command on d-q axis, and suppressing voltage variations at the neutral point by correcting a voltage command on d-q axis based on the d-q voltage correction command. The neutral point is connected to one grounded phase of a three-phase grounded power system. The alternating-current output terminals are connected to respective non-grounded phases of the power system. A power conditioner includes the three-level inverter.

Abstract: A matrix converter according to one aspect of an embodiment includes a plurality of bidirectional switches and a controller. The bidirectional switches connect each phase of an alternating current (AC) power supply with each phase of the rotary electric machine. The controller performs power conversion control between the AC power supply and the rotary electric machine by controlling a plurality of unidirectional switching elements constituting the bidirectional switches individually. The controller performs switching control for advancing the timing at which the unidirectional switching elements constituting the bidirectional switches are switched ON from that in 120-degree conduction control, and for extending a period for which the unidirectional switching elements are kept ON from that in the 120-degree conduction control.

Abstract: A matrix converter according to an embodiment includes a plurality of bidirectional switches and a controller. The bidirectional switches connect each of phases of an alternating current (AC) power supply with each of phases of a rotary electric machine. The controller controls the bidirectional switches to perform power conversion control between the AC power supply and the rotary electric machine. The controller performs on/off control individually on a plurality of unidirectional switching elements constituting the bidirectional switches by using both 120-degree conduction control and PWM control.

Abstract: A current-source power converting apparatus includes: a converter unit configured to convert an AC or DC voltage input from a power supply into a predetermined DC voltage; an inverter unit configured to convert a DC voltage supplied from the converter unit via a DC reactor into an AC voltage and output the AC voltage; and a controller configured to control the inverter unit at a modulation factor in correspondence with a step up/step down ratio based on a ratio of an output voltage from the inverter unit to an input voltage from the power supply.

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 power converting apparatus according to an embodiment includes a controller that controls a power converter. The controller includes a first signal generator which generates switch drive signals for AC-to-DC conversion, a second signal generator which generates switch drive signals for DC-to-AC conversion, and a drive signal generator which generates, in accordance with the switch drive signals for AC-to-DC conversion and the switch drive signals for DC-to-AC conversion, switch drive signals for controlling the power converter. The first signal generator and the second signal generator operate in synchronization with each other.

Abstract: A current-source power converting apparatus according to an embodiment includes an inverter and a drive controller. The inverter includes, in every output phase, a plurality of switching elements that are serially connected between the positive pole and the negative pole of a direct current source. The drive controller controls the inverter in accordance with a current command in an output mode of controlling the switching elements of different output phases for supplying current between the output phases and a short circuit mode of controlling the switching elements of the same output phase. An output phase in which the drive controller executes the short circuit mode is an output phase whose phase voltage or phase current has the minimum absolute value.

Abstract: A power conversion apparatus includes two power conversion circuits, two direct-current inductors, and a pulse-width-modulation control circuit. One of the two power conversion circuits is connected in parallel to a direct-current load or a single-phase alternating-current load, and the other of the two power conversion circuits is connected in parallel to a three-phase alternating-current load. The two power conversion circuits are connected in reverse polarity to each other via the two direct-current inductors. The pulse-width-modulation control circuit pulse-width-modulates the two power conversion circuits, allows switching between the two power conversion circuits, and realizes a bidirectional step-up/down operation between the direct-current load or single-phase alternating-current load and the three-phase alternating-current load.

Abstract: Provided is a linear motor device which is compact even when a stroke is increased, which can reduce heat generation, and which can eliminate damping force caused by circulating current. The linear motor device includes a linear motor that includes a movable member having a plurality of fields and a stator in which a plurality of armatures including polyphase coils are arranged in line in the moving direction of the movable member, and a controller that sequentially outputs control commands to current amplifiers respectively connected to the armatures in accordance with the relative position of the movable member. The controller selectively outputs the control commands to only the current amplifiers corresponding to the armatures which are opposite the movable member such that the armatures are positioned within a range corresponding to the length in the moving direction of the movable member.