Hitachi Medical Corporation

Hitachi, Ltd.

Takuya Domoto

Hiroshi Takano

Hirokazu Iijima

Hiroyuki Takeuchi

Hiroshi Morita

Jun Takahashi

Takanobu Hatakeyama

Shingo Hishikawa

Takayuki Masaki

Toranosuke Takeuchi

Tomoharu Ino

Takatsugu Oketa

Keiichi Chabata

Downsizing a Cockcroft-Walton high-voltage generation device may cause discharge from the connections of respective components to potentially lack insulation reliability. A Cockcroft-Walton circuit () is configured to include capacitors (-to-) connected in series and capacitors (-to-) connected in series, each having end electrodes () at both ends, respectively. One capacitor (-) is electrically connected with the other capacitor (-), which is adjacent in series to the former at a connection (-). The connection (-) is arranged so as not to protrude outside a first space () between the end electrode () of the one capacitor (-) and the end electrode () of the other capacitor (-). Further, the anode of a diode (-) and the cathode of a diode (-) are electrically connected to the connection (-).

High-voltage generation device and X-ray generation device

A power converter is configured to include an inverter which converts a DC output into an AC voltage of a predetermined frequency, and a high voltage generator which receives an output from output terminals of the inverter and boosts the output to a desired high DC voltage. The high voltage generator includes a transformer, and the primary windings of the transformer are connected to the output terminals of the inverter in parallel by conductive wires connected to both ends of each primary winding. Further, a current sensor is provided to detect a current flowing through each of the primary windings, and a control unit determines abnormalities of a path of the inverter and the primary windings on the basis of a value of the current sensor.

Power converter, X-ray CT apparatus, and X-ray imaging apparatus

There is provided an inverter device that can detect short-circuit of a switching element of an inverter circuit even under a load condition that a PWM driving signal is very small. The inverter device is provided with means for independently supplying a short-circuit detecting PWM driving signal to respective switching elements Sto Sat different timings before the inverter circuitsupplies a PWM driving signal for supplying power to a high voltage generating device, successively turning on the respective switching elements Sto Swith the short-circuit detecting PWM driving signal, detecting on-voltages of the switching elements Sto Swhich are connected to the turned-on switching elements Sto Sin series, and detecting overcurrent or short-circuit states of the switching elements Sto S

Inverter device and X-ray high-voltage device using the inverter device

A DC high voltage power source is constituted by an AC-DC converting means () that converts a voltage of a commercial AC power source () to a DC voltage and steps up the converted DC voltage, a DC-AC converting means () that converts the DC voltage stepped up by the previous means to an AC voltage, two insulating transformer () that steps up the AC voltage converted by the previous converting means while insulating each others and a series connection of DC voltages obtained after converting the output voltages from the transformers to DCs and smoothing the same. The DC voltage of the DC high voltage power source is used as the power source to current amplifiers () constituted by a multi level PWM inverter circuit () of 3 levels and the currents flowing through X axis, Y axis and Z axis gradient magnetic field coil () in an MRI apparatus connected to these current amplifiers as loads are controlled by a switching control device () so as to meet with current command values () from a sequencerin the MRI apparatus. As a result, plural DC high voltage power sources necessary for the multi level PWM inverter is constituted by a comparatively simple circuit, in addition, while suppressing loss in the power sources, a small sized and highly accurate high voltage and large current power source device and a magnetic resonance imaging apparatus using the same are provided.

Power source device and magnetic resonance imaging apparatus using the same

In an X-ray generating device of the neutral grounding system, to remove an unbalance voltage generated due to difference in impedance of parallel transformer coils of the high voltage transformer and particularly an unbalance voltage involved with difference in impedance above and below the neutral points generated in a metal X-ray tube, a plurality of currents flowing in opposite directions through primary windings of the parallel transformer coils in the high voltage transformer are passed through by or wound around a common toroidal coil or wound around an outer circumference of the toroidal coil at a predetermined ratio of winding number, and the unbalance voltage occurring to the secondary side is cancelled by changing primary current with magnetic behavior.

X-ray generator and X-ray CT apparatus comprising same

An X-ray tube apparatus () having an anode rotating mechanism for preventing damage of the anode () of the X-ray tube apparatus thereby to shorten the X-ray exposure waiting time. When the measured number of revolutions of a rotary anode is determined to be predetermined number from only the impedance or current information on the basis of both voltage information and current information on a stator coil () of motor constituent elements for rotating the rotary anode, a DC high voltage outputted from an X-ray high-voltage unit () is applied between the anode () and a cathode () of the X-ray tube apparatus, thus exposing a subject () to X-rays and imaging the subject. An X-ray generating device and a radiograph are also disclosed.

X-ray apparatus with anode rotation number detecting means

A power source apparatus distributes a current command value to be supplied to a load to a plurality of output current amplifiers connected in parallel with the load, and each of the output current amplifiers supplies an output current corresponding to the current command value so distributed. This power source apparatus prevents a circulating current between the output current amplifiers by controlling each output current amplifier so that the difference between the output current from each output current amplifier and the distributed current command value becomes zero, or by inserting current limiting devices into the output line of each output current amplifier.

Growing community of inventors

Tokyo, Japan

Takuya Domoto