Hitachi, Ltd.

Hitachi Automotive Systems, Ltd.

Hitachi Industrial Products, Ltd.

Hitachi Industrial Equipment Systems Co., Ltd.

Hitachi Astemo Ltd.

Kimihisa Furukawa

Yuuichi Mabuchi

Mizuki Nakahara

Akihiko Kanouda

Toshiyuki Ajima

Takashi Ogawa

Takae Shimada

Junichi Sakano

Hiroyuki Yamada

Hideki Miyazaki

Satoru Kaneko

Yuki Kawaguchi

Shigehisa Aoyagi

Tokihito Suwa

Takuro Kanazawa

Tohma Yamaguchi

Hiroshi Kamizuma

Mitsuhiro Kadota

Kenta Katsuhama

Yuuichirou Takamune

Kinya Nakatsu

Yoshinobu Kimura

Daisuke Goto

Akinori Kamiya

Tatsuyuki Yamamoto

Hiroyuki Shoji

Hiroki Takeda

Shigeyuki Yoshihara

Hirooki Tokoi

Shintaro Tanaka

Kohei Myoen

Hajime Urai

Toshisada Mitsui

Masaki Kashima

Hisashi Endou

Noriya Nakao

Renichi Yamada

Shingo Nishiguchi

Yuichiro Takamune

Kazuto Ooyama

Satoru Ohno

Katsuyo Tsushima

Meirai Ko

A plurality of power conversion units, a current sensor that detects a current at an output terminal of the power conversion unit, and a control unit that measures a frequency component in a predetermined frequency range of a current detected by the current sensor are included, the power conversion unit includes an AC/DC converter that outputs AC power at an input terminal to an output terminal, a smoothing capacitor that is connected in parallel to the output terminal and smooths an output voltage, and a variable resistance switch connected between one end of the smoothing capacitor and one end of the output terminal, the control unit controls a resistance value of the variable resistance switch according to a magnitude of a predetermined frequency component detected by the current sensor, and the output terminals of the plurality of power conversion units are connected in parallel to constitute output terminals.

Power conversion device

This power converter device is appropriately configured. Accordingly, a power converter device comprises, for each phase of a three-phase AC, an AC wiring through which AC terminals of a plurality of power conversion units are series-connected along a second direction. Among the power conversion units, power conversion units that correspond to a first phase are series-connected from a first phase line toward a neutral line in a first direction along the second direction. Among the power conversion units, power conversion units that correspond to a second phase adjacent to the first phase are series-connected from a second phase line toward the neutral line in a second direction opposite to the first direction.

Power converter device

Provided is a power conversion system that can suppress a fault in a short-circuiting switch that bypasses a fault unit and enhance the reliability and redundancy of the system. The power conversion system is provided with a plurality of power converter units that are formed by using semiconductor switch elements and are connected in series, and comprises: switch elements that are provided to input terminals and/or output terminals of the power converter units and bypass the power converter units; and overvoltage suppressing elements which are connected in parallel with the switch elements and in which conducting states are changed by an application of a prescribed voltage.

Power conversion system

A power conversion device and a press apparatus capable of preventing an excessive current in a DC-link capacitor are provided. The power conversion deviceincludes a voltage-doubling rectifier circuit. In the voltage-doubling rectifier circuit, in a voltage-doubling rectification mode, a common connection node Nc between two capacitorsandis connected to a predetermined node. A current detector circuitdetects a switching current (IL) flowing in the switching elements SWand SW, and a current detector circuitdetects a load current Ild of a load. In a mode switching period from a full-wave rectification mode to a voltage-doubling rectification mode, a controller circuitcontrols the switching of the switching elements SWand SW, based on the switching current (IL) and the load current Ild.

Power conversion device and press apparatus

An object of the present invention is to sufficiently reduce a switching loss. A control device causes a positive electrode of a first voltage to appear at a second connection point by switching second and third switching elements to an ON state. Next, the control device causes the positive electrode of the first voltage to appear at a first connection point by switching the second and third switching elements to an OFF state. After that, fifth and eighth switching elements are switched to the OFF state, and sixth and seventh switching elements are switched to the ON state.

Power conversion device, power conversion device control device, and power conversion device control method

The power conversion device includes multiple converter cells. Each converter cell includes a pair of primary-side terminals and a pair of secondary-side terminals. The converter cell transmits power between the pair of primary-side terminals and the pair of secondary-side terminals. The primary-side terminals of the multiple converter cells are connected in series to a primary-side power supply system. The secondary-side terminals of the multiple converter cells are connected in series to a secondary-side power supply system. Among the multiple converter cells, the converter cell in which an absolute value of a ground voltage appearing in the pair of primary-side terminals is the highest is different from the converter cell in which an absolute value of a ground voltage appearing in the pair of secondary-side terminals is the highest.

Power conversion device and power conversion device connection method

A power conversion device that suppresses voltage pulsation of a capacitor of a power converter with respect to a control target whose effective power is to be controlled is provided. The power conversion device includes a plurality of power conversion cells that are connected to each other, and convert a primary-side system voltage into a secondary-side system voltage, a capacitor that is connected to each of the plurality of power conversion cells, and a power conversion cell driver that drives the power conversion cells to add a 3N order higher-harmonic-wave voltage of each of alternating voltages of the plurality of power conversion cells to the each of alternating voltages, and output a voltage made by adding the each of alternating voltages and the 3N order higher-harmonic-wave voltage, when N is a natural number.

Provided is a power conversion device which can be configured inexpensively and in which initial charging can be performed quickly. Accordingly, the power conversion device is provided with: a power conversion device cell having a first converter for converting a first AC voltage to a first DC voltage, a second converter for converting the first DC voltage to another voltage, and a first capacitor charged by the first DC voltage; and a control circuit for allowing charging of the first capacitor while changing the operational state of the first converter in accordance with the first DC voltage.

A diagnostic system for a power conversion apparatus including a semiconductor device and performing a switching operation for carrying and interrupting a main current to a main current is disclosed. This system includes a trigger circuit that acquires reference time for the switching operation; and a delay time calculation circuit that acquires first time at which the main current takes a first main current set value and second time at which the main current takes a second main current set value, and that detects numerical data about a difference between the first time and the reference time and numerical data about a difference between the second time and the reference time.

Diagnosis system for power conversion device, diagnosis method for semiconductor module, and power conversion device

Magnetic flux generated when a current flows through a main circuit wiring serves as disturbance of a magnetic sensor, and accurate rotor position information is obtained. A motor drive apparatus controls an operation of a power conversion device outputting a current to an AC motor on the basis of a desired torque command value, and includes a main circuit wiring that is electrically connected to a switching element forming the power conversion device, and through which a DC current or an AC current is transmitted thereto, a magnetic sensor that detects a magnetic flux change of a sensor magnet attached to a rotor of the AC motor, and a controller that calculates a current command value which is output from the power conversion device to the motor on the basis of position information of the rotor detected by the magnetic sensor, in which the controller includes a magnetic flux error correction unit that detects or calculates a magnetic flux component generated by a current flowing through the main circuit wiring.

Power conversion device and motor drive apparatus

An object of the invention is to simultaneously solve a miniaturization and an improvement of productivity of a power conversion device, a temperature rise suppression of a smoothing capacitor, and a reduction of motor noises. The power conversion device of the invention includes a smoothing capacitor, a first power conversion unit and a second power conversion unit which are connected in parallel, and a control unit which generates a PWM pulse on the basis of an output voltage vector and a PWM carrier. The control unit includes a correction unit which corrects a predetermined output voltage vector value to two or more different output voltage vector values such that an average value in one period of the PWM carrier becomes the predetermined output voltage vector value. The correction unit corrects a first output voltage vector value in a first period, and corrects a second output voltage vector value in a second period different from the first period.

Power conversion device and electric power steering device using the same

The present invention relates to a power conversion device in the power electronics field. An object of the present invention is to provide a technique of determining whether a switching element operates normally or not from a gate monitor signal of a power conversion device, and predicting a sign of a failure by obtaining the temperature of the switching element from a transient state of the switching voltage of the power conversion circuit as a component of the power conversion device without using a new signal path.

A diagnostic system for a power converter which includes a semiconductor device, and which performs a switching operation between conduction and interruption of the principal current flowing through a main circuit. The diagnostic system includes a current change amount calculation circuit for obtaining numeric data which reflects a current change amount of the principal current per unit time, a determination circuit for determining a state of the power converter by comparing the numeric data with a reference value, and an output circuit for outputting a determination result of the determination circuit.

Power converter, diagnostic system of power converter, and power converter diagnostic method using current change

Provided are an inverter device deterring PWM voltage error even if high inverter output frequencies are used for overmodulation driving and an electric vehicle equipped with the inverter device. In an angular section where the output voltage from an inverter device is linearly approximated with the zero cross point as the center thereof, a PWM generator in the inverter device changes either the time interval between the centers of PWM ON pulses or the time interval between the centers of PWM OFF pulses depending on the inverter operation state. An electric vehicle is equipped with the inverter device, which drives a motor.

Inverter device and electric vehicle

An inverter device includes a source current calculator and an inverter circuit, wherein: the source current calculator calculates an average value of the DC bus current Ical during a PWM cycle through arithmetic operation executed based upon instantaneous values of the DC bus current Idc of the inverter circuit; and the source current calculator provides an estimated value by designating the average current value Ical during the PWM cycle as an input source current Isrc during the PWM cycle.

Inverter device

Growing community of inventors

Tokyo, Japan

Kimihisa Furukawa