Hitachi, Ltd.

Hitachi Information & Control Solutions, Ltd.

Hitachi Power Semiconductor Device, Ltd.

Canon Aptex Kabushiki Kaisha

Kenji Sakurai

Yasuhiro Watanabe

Mitsuhiro Mishima

Tsuyoshi Tanaka

Daisuke Maeda

Hiroyuki Hasegawa

Tsunehiro Endo

Junnosuke Nakatsugawa

Atsushi Sasaki

Hidefumi Shirahama

Mitsuhiro Mukasa

Satoshi Iesaka

Tunehiro Endo

Tomoyuki Utsumi

Katsuo Nakayama

Tomoya Taniguchi

Shoichi Ohozeki

The upper arm drive circuit for controlling the drive of an upper arm switching element of the power conversion device includes: an upper arm gate voltage output wiring connected to a gate of the upper arm switching element; a first upper arm drive circuit reference potential wiring; an upper arm gate voltage reference potential wiring connected to an inverter output of the power conversion device; and a control circuit of upper arm drive circuit reference potential wiring potential for controlling the potential of the first upper arm drive circuit reference potential wiring to a potential lower than a reference potential when a potential of the inverter output is equal to a predefined potential that is lower than the reference potential or lower. The first upper arm drive circuit reference potential wiring is connected to the reference potential via the control circuit of upper arm drive circuit reference potential wiring potential.

Upper arm drive circuit, drive circuit of power conversion device, and power conversion device

The upper arm drive circuit for controlling drive of the upper arm switching element of the power conversion device includes: a capacitor disposed between a gate of the upper switching element and the output terminal of the power conversion device; a reverse current prevention circuit that is disposed between a power supply of the power conversion device and the capacitor, and that makes a current flow from a first terminal side of the reverse current prevention circuit connected to the power supply side to a second terminal side of the reverse current prevention circuit connected to the capacitor side and prevents a reverse current from flowing from the second terminal side to the first terminal side; and a switching element for capacitor charging that is turned ON in synchronization with a command signal that turns the upper arm switching element ON.

Upper arm drive circuit having a reverse current prevention circuit disposed between a power supply of a power conversion device and a first capacitor and control method thereof

A synchronous motor including therein a three-phase inverter and position sensors, having a unit for calculating a digital input current value from the analog output of an input current detection circuit that detects the input current flowing into the DC input terminal of the three-phase inverter, and a digital feedback speed control unit for adjusting the amplitudes and frequency of the AC voltages outputted from the three-phase inverter in such a manner that the motor speed calculated by a motor speed calculation uniton the basis of the outputs of the position sensors approaches a speed command value received by a communication reception unit from outside the synchronous motor. The synchronous motor further includes therein a communication transmission unit for transmitting the input current value and the motor speed to outside the synchronous motor.

Synchronous motor and control method of synchronous motor

The synchronous motor driving apparatus including position sensors provided in the synchronous motor, a current polarity detection circuit for detecting the polarities of the currents in the respective phase windings of the synchronous motor, an inverter driving the synchronous motor, a motor speed calculation unit calculating the rotational speed of the synchronous motor depending on the output signals from the position sensors, a speed control unit outputting a first voltage adjusting component (q-axis current command value Iq*) to cause the rotational speed of the synchronous motor to approach a speed command value and a phase control unit outputting a second voltage adjusting component (d-axis current command value Id*) to cause the phase differences between the phases of the position sensor signals and of the currents in the respective phase windings of the synchronous motor to become a predetermined value.

Apparatus and method for driving synchronous motor

In order to prevent a short circuit of top and bottom arms of a motor driving IC when noise is added to six control signals for controlling six switching elements, there is provided a semiconductor device for driving a motor, being sealed with resin as one package and comprising: six switching elements for driving a three-phase motor; three output terminals for outputting voltages to the three-phase motor; at least one driving circuit for driving the six switching elements; three control signal input terminals; and a function) of generating six control signals for control of the six switching elements based on three control signals inputted through the three control signal input terminals.

Semiconductor device for driving motor, three-phase motor and motor driving apparatus with the semiconductor device and fan motor

A motor driving semiconductor device has: six switching elements for driving a three-phase motor; three output terminals for applying output voltages to three terminals of coils of the three-phase motor; drive circuits for driving the six switching elements; and six control signal input terminals for receiving six control signals for on/off control of the six switching elements, wherein the motor driving semiconductor device is formed by sealing at least one semiconductor chip in one package with resin, and further includes a dead time generation function of generating a dead time relative to the six control signals.

Semiconductor device for motor driving and motor having the same, motor driving apparatus and air conditioner

A control apparatus and a semiconductor apparatus of AC motors capable of reducing torque ripple with a comparatively simple circuit corresponding to a high withstand voltage and capable of driving a motor at high efficiency even when the rotational speed or load has changed. The control apparatus detects first phase signals fixed in relative phase to induced voltages of the motor and current polarity signals, recognizes phase differences between them, generates second phase signals so as to make the phase differences approach zero to drive the motor at high efficiency, generates modulation wave signals having quasi-sinusoidal waveforms or trapezoidal waveforms on the basis of the second phase signals, compares the modulation wave signals with a carrier wave signal, and conducts PWM control on an inverter.

Control apparatus, dual chip inverter and single chip inverter of AC motors

In a recording apparatus for stably conveying a recording medium to a recording portion by a convey belt, the recording medium is passed through a nip of a pair of separation supply rollers and enters into a nip between a convey belt and a driven roller and thereafter is conveyed by the convey belt to a recording portion. When a leading end of the recording medium is detected by a recording medium detect sensor, the supply roller is disengaged from the separation roller, so that the convey belt is not subjected to the influence of the pair of separation supply rollers via the recording medium and when a trailing end of the recording medium is detected by a recording medium detect sensor, the driven roller is disengaged from the convey belt, so that the recording medium is not subjected to conveyance resistance from the driven roller.

Recording apparatus

A sheet feeding device is provided with a sheet feeding unit for feeding sheets supported on a sheet support means, and sheet separator means provided downstream of the sheet feeding unit with respect to the sheet feeding direction, the sheets fed by the sheet feeding unit being separated one by one by the sheet separator and fed. The sheet separator is comprised of an inclined surface against which the sheet fed by the sheet feeding unit abuts, a dash member provided downstream of the inclined surface with respect to the sheet feeding direction and against which the leading end of the sheet riding over the inclined surface abuts, and a resilient member for displaceably supporting the dash member when the sheet abuts against the dash member.

Growing community of inventors

Hitachi, Japan

Kenji Sakurai