Kabushiki Kaisha Yaskawa Denki

Katsutoshi Yamanaka

Kenji Yamada

Eiji Watanabe

Yoshiyuki Tanaka

Koji Higashikawa

Takashi Kuboyama

Yushi Takatsuka

Takaaki Terada

Shinya Morimoto

Toru Shikayama

Hidenori Hara

Toshihiro Sawa

Sadao Ishii

Tsuyoshi Higuchi

Michihiko Zenke

Jun-Koo Kang

Yuuichi Terazono

Akira Kumagai

Akira Kumagae

Eijiro Tajima

Yutaro Ihara

Noritaka Koga

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.

Electric power converter and control method for electric power converter

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.

Power converting apparatus

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.

Alternating-current/direct-current converter

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.

Current-source power converting apparatus

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.

Power conversion device

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.

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.

Power converter

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. A power generating system includes the power conditioner.

Three-level inverter, power conditioner, and power generating system

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.

Power conversion apparatus

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.

Linear motor device

A winding switching apparatus includes a winding switching device and a drive circuit. The winding switching device is configured to switch a plurality of windings of an AC motor. The drive circuit is configured to control the winding switching device. The winding switching device includes a winding switch, a diode bridge, and a capacitor. The diode bridge includes a positive-side DC output terminal, a negative-side DC output terminal, and AC input terminals. The AC input terminals corresponds to respective phases of the AC motor. The positive-side and negative-side DC output terminals are respectively connected to positive-side and negative-side DC buses provided in an inverter. The AC input terminals are respectively connected to winding-switching terminals corresponding to the respective phases of the AC motor. The AC input terminals are respectively connected to phase terminals provided in the winding switch.

Winding switching apparatus and winding switching system

A winding switching apparatus for switching windings of an AC three-phase motor is provided. In each winding switching section of the winding switching apparatus, a positive-side charging resistor, a negative-side charging resistor, and a capacitor are connected in series between a positive-side DC bus and a negative-side DC bus of an inverter; the positive side of the capacitor is connected to the cathodes of respective diodes of a diode unit; and switching between high-speed windings and low-speed windings is carried out, with a capacitor potential being the same as an inverter DC bus voltage. A state detector and a comparator are also provided for each winding switching section to detect erroneous wiring and component abnormalities.

Apparatus for switching windings of AC three-phase motor

A power conversion device includes a main circuit that has switches connecting each phase of a three-phase AC power supply to each output phase, an LC filter having a reactor and a capacitor connected between the three-phase AC power supply and each bidirectional switch, and a current detector detecting an input current or a load current, and a four-step commutation device generating four steps on the basis of the polarity of the load current. The four-step commutation device sets times between the steps to a value more than zero so as to inhibit open circuit between output phases and short circuit between power supply phases, and sets the times between the steps in accordance with the polarity of the load current so as to cancel a distortion of an output voltage due to four-step commutation during a PWM cycle.

A power conversion method comprising detecting a three-phase source voltage of the three-phase AC power supply every control sampling cycle. The three-phase source voltage is allocated to a maximum voltage, an intermediate voltage and a minimum voltage as seen from a virtual neutral point voltage. A one-phase fixing switching mode is detected for fixing one of output phases into a predetermined state without switching and switching the other phases during a PWM cycle or a full phase switching mode for switching all of the phases during the PWM cycle based on an output voltage command and the three-phase source voltage. ON/OFF pattern of a bidirectional switch is determined from the switching mode thus selected, the output voltage command and the three-phase source voltage. The bidirectional switch is turned ON/OFF based on the ON/OFF pattern.

Apparatus for three phase PWM cycloconverter

A PWM inverter with a PWM pulse output. The PWM pulse signal is output upon magnitude comparison of phase voltage commands with a carrier wave of a triangular or a saw-tooth waveform. A maximum phase whose absolute value is a maximum among absolute values of phases of the phase voltage commands is selected. In a case where the phase voltage commands of the maximum phase are larger than a maximum value of the carrier wave. A difference obtained from a first subtraction of the maximum value of the carrier wave from phase voltage commands of the maximum phase is set as a first differential. The first differential is subtracted from the phase voltage commands of the respective phases in a second subtraction. The first and second subtraction results are set as phase output voltage commands of the respective phases.

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Fukuoka, Japan

Katsutoshi Yamanaka