Hitachi Medical Corporation

Fujifilm Healthcare Corporation

National University Cooperation Nagaoka University of Technology

Institute of National College of Technology

Mina Ogawa

Yuki Kawaguchi

Kiyoshi Ohishi

Takayuki Masaki

Syoutarou Shindou

Itaru Ando

Shoutaro Shindo

A power conversion device comprising: a three-phase conversion circuit in which each of upper arm elements which are switching elements in an upper arm and each of lower arm elements which are switching elements in a lower arm are provided for each of three phases; and a switching control unit which alternately switches between an upper arm period of holding one of the upper arm elements ON and a lower arm period of holding one of the lower arm elements ON, wherein the switching control unit switches between the upper arm period and the lower arm period, based on an integrated value of power which is calculated by integrating a power pattern which is set beforehand.

Power conversion device, X-ray image capturing apparatus, and motor drive device

An inverter circuit allowing a single drive circuit to perform both tracking control for tracking resonance frequency fluctuations caused by load fluctuations, and power control, thereby reducing switching loss. An inverter drive circuit part obtains a phase difference between output current and output voltage directed to a load circuit connected to a midpoint of two arm circuits of the inverter circuit, and controls a phase of the driving signal directed to each semiconductor switch such that the phase difference becomes zero or a predetermined value, enabling an operating frequency of the inverter circuit part to track a resonance frequency of the load circuit, and enabling a current phase to be delayed with respect to a voltage phase, thereby achieving ZCS. Since the phase difference is used, an auxiliary circuit is not necessary for measuring a current value in proximity to the semiconductor switches.

Phase shift inverter, X-ray high-voltage device using same, X-ray CT device, and X-ray imaging device

Growing community of inventors

Tokyo, Japan

Mina Ogawa