Hitachi, Ltd.

Other

Hitachi Engineering Co., Ltd.

Toshisuke Mine

Hiromi Inaba

Toshiaki Kurosawa

Takeki Ando

Takao Kishikawa

Hideaki Takahashi

Yoshio Sakai

Kiyoshi Nakamura

Seiya Shima

Sadao Hokari

Masao Nakazato

Katsu Komuro

Toshifumi Yoshikawa

Noboru Arabori

Satoshi Fukuda

Kazuhisa Mori

Naoto Ohnuma

Hajime Nakashima

Tomoharu Sakoda

Asako Koyanagi

A driving system for driving an AC motor, which is capable of promptly switching to an individual inverter operation mode, wherein a control instruction for each of a plurality of power converters is generated by summing outputs of a plurality of current compensation units connected in parallel, and each of the plurality of current compensation units makes compensation to reduce a deviation of a detected output current value of an associated power converter from a current instruction value to be outputted from the power converter to zero.

Driving system for driving AC motor

A semiconductor electric power conversion device includes a converter unit and an inverter unit, each having a group of parallel capacitors and multiple switching elements. Subdivided positive conductive connections associated with the converter unit and divided positive conductive connections associated with the inverter unit are formed at a positive side conductor connected to capacitors; while divided negative conductive connections associated with the converter unit and divided negative-polarity conductive connections associated with the inverter unit are formed at a negative polarity side conductor, connected to capacitors. The positive and negative polarity conductors have a multilayer structure with a dielectric plate interposed therebetween. Converter positive and negative polarity conductors are formed into a multilayer structure with the dielectric plate sandwiched between them, and inverter positive and negative polarity conductors are formed into a multilayer structure with the dielectric plate sandwiched therebetween.

Semiconductor electric power conversion device

In a current source power converting apparatus, in which an AC to DC converter is coupled to a DC to AC inverter through a DC reactor, two energy absorbing devices are coupled to DC terminals of the converter and the inverter, respectively, whereby there is formed a circulation circuit for circulating a current through the two energy absorbing devices and the DC reactor, when a voltage, which is higher than a predetermined value, is induced by an inductance of the DC reactor.

Current source power converting apparatus with overvoltage protection

An inverter, which supplies an induction motor for driving an elevator with DC power, is controlled by means of a vector control method. A rotating angular speed of the induction motor is detected from a torque component of a detected motor current. A present position of an elevator cage is calculated on the basis of the detected rotating angular speed.

Elevator control apparatus

A dv/dt protection circuit device for an AC-DC converter apparatus including control board switching arrangement having a current cut-off function which conducts an interrupts current from a power source to a load and refluxes the load current while the current is uninterrupted by a full-wave bridge rectifier circuit having a plurality of arms. Each arm of the bridge rectifier circuit connects a reactor for suppressing a rate of change of a power source line voltage of the bridge rectifier circuit at the switching time of the switching arrangement and a condenser is provided for absorbing an overvoltage generated at an inductance on the side of the power source, the condenser being connected on the side of the power source connected to the bridge rectifier circuit.

dv/dt Protection circuit device for an AC-DC converter apparatus

Growing community of inventors

Katsuta, Japan

Toshisuke Mine