Mitsubishi Denki Kabushiki Kaisha

Yuuji Kuramoto

Tatsuya Okuda

Dai Nakajima

Takahiro Urakabe

Tohru Kimura

Toru Kimura

Hirotoshi Maekawa

Naoki Yoshimatsu

Kiyoharu Anzai

Toshiyuki Kikunaga

Takanobu Yoshida

Masakazu Fukada

Takeshi Ohi

Toshinori Yamane

Majumdar Gourab

A motor driving apparatus makes a carrier signal of an inverter be synchronized with a carrier signal of a DC/DC converter, and determines a phase difference between both the carrier signals based on a ratio of an input voltage inputted to the DC/DC converter and an input voltage inputted to the inverter, and a percentage of modulation and a power factor which are operation parameters of the inverter. When the frequency of the carrier signal of the DC/DC converter is set to be twice as high as that of the carrier signal of the inverter, an optimal phase difference is determined based on the ratio of the input voltage of the DC/DC converter and the input voltage of the inverter.

Motor driving apparatus

A motor driving apparatus is provided which can minimize ripple current flowing through a DC link capacitor, and downsize the motor driving apparatus. It synchronizes the frequency of the inverter carrier signal for driving an inverter with the frequency of the DC/DC converter carrier signal for driving a DC/DC converter, and carries out control in such a manner that the center of a period during which the input current of the inverter is zero and the center of a period during which the output current of the DC/DC converter is zero are matched.

A capacitor module incorporating a ceramic capacitor having terminal members for reducing stress caused by thermal stress or electrostriction in the ceramic capacitor itself, and a semiconductor device using the capacitor module. The capacitor module and the semiconductor device are designed to have a reduced size and improved reliability. The semiconductor device has a power converter circuit constituted by switching devices and diodes, a P-polarity conductor and an N-polarity conductor for supplying electric power to the power converter circuit, a ceramic capacitor having two external electrodes, flexible terminal members connected to the external electrodes, a heat radiation plate provided at the bottom of a case, an insulating resin with which the power converter circuit is covered, a P-polarity connection conductor for connection between the terminal member on one side of the ceramic capacitor and the P-polarity conductor, an N-polarity connection conductor for connection between the terminal member on the other side of the ceramic capacitor and the N-polarity conductor, and a molded wiring plate on which a major surface of the ceramic capacitor is supported.

Capacitor module and semiconductor device using the same

P-electrode and N-electrode of a semiconductor device and capacitors in a plate-like shape or a block-like shape respectively connected to U-phase V-phase and W-phase having a switching element and a diode are built in a semiconductor device and a single or a plurality of capacitors are respectively connected to P-electrodes and N-electrodes in each of the phases, whereby the smoothing capacitors are built in the semiconductor device to reduce wiring inductances, the capacitors are miniaturized, and an entire electric power converting device, i.e. inverter, is miniaturized.

Semiconductor device having built-in capacitors

Conventionally, there is a problem that it is impossible to provide an analog signal detecting circuit having high reliability and long lifetime under a bad environment since a photocoupler is used for electrical insulation of a digital signal. Then, an analog signal detecting circuit is provided with a carrier wave generating unit for generating a carrier wave, a pulse width modulating unit for pulse width modulating an analog signal inputted from the signal input terminal by using the carrier wave generated by the carrier wave generating unit and for outputting a digital signal, a reverse level shift HVIC for transmitting the digital signal from one power supply system to the other power supply system, and a demodulation unit for demodulating the digital signal transmitted to the other power supply system into an analog signal and for outputting it to a signal output terminal. As a result, even in the case where reference potentials are different from each other at signal input/output terminals, an analog signal can be detected.

Analog signal detecting circuit, and AC side current detector of semiconductor power conversion device

Growing community of inventors

Tokyo, Japan

Yuuji Kuramoto