Hitachi, Ltd.

Hitachi Engineering Co., Ltd.

Hitachi Metals, Ltd.

Hitachi Device Engineering Co., Ltd.

Yasuo Matsuda

Kenichi Onda

Norikazu Tokunaga

Kazuo Honda

Hideki Miyazaki

Nobuyoshi Muto

Hisao Amano

Takeo Maeda

Keijiro Sakai

Ikuo Yamato

Mitsuyuki Honbu

Yutaka Suzuki

Shigeta Ueda

Mitsuyuki Hombu

Yasuyuki Sugiura

Tadashi Okawa

Akihiko Kanouda

Katsunori Suzuki

Kozo Watanabe

Hiroshi Nagase

Shin Kimura

Hidefumi Shirahama

Hironori Okuda

Shuji Musha

Hiroshi Fukui

Mutsuhiro Mori

Shigeki Morinaga

Kunio Miyashita

Takanori Shibata

Satoshi Ibori

Naoki Sakurai

Nobuyoshi Mutoh

Hiroyuki Aoyama

Masayoshi Sato

Tomoyuki Tanaka

Yasumichi Yasuda

Hiroshi Hayashida

Hiroo Konishi

Kenji Nandoh

Kouzou Watanabe

Yuzo Morita

Hisakazu Ninomiya

Teruaki Odaka

Yasunori Iwafuji

Takao Yaginuma

Kojin Abe

Toshiki Kurosu

Takeshi Nagano

Mitsufumi Iwanaka

Youuji Ishida

Kouichi Mizuta

Akihoko Kanouda

Shuuji Musha

Kunio Miyasita

Takuji Matsumura

Toshio Kawaguchi

Yoshiki Kajita

Masayoshi Satoo

Hideo Yoshinaka

A power supply control system including a variable power converter for converting electric power from a power supply to a load into that of a specification required by the load in response to a power specification information source provided on the load side. With a change in the load, the information source also changes, thereby providing a flexible power supply control system capable of meeting different loads. For applications to a high power supply, the system comprises a plurality of variable power converters adapted to operate selectively in accordance with requisite power information sources provided in or on the side of a plurality of loads, thereby providing a system realizing a flexible power supply. For application to a low power supply, the system comprises a plug having a power specification information source and a socket having a variable power converter.

Power supply control system

In a module using a high-speed switching element such as an IGBT for a high-speed inverter, a matching condition is established between the switching characteristic of the IGBT and the recovery characteristic of the diode to be connected thereto in an anti-parallel fashion. As a result, the oscillating voltage appearing in the inverter circuit is suppressed to prevent erroneous operation of the inverter system.

Parallel circuit module including a diode and an IGBT

The switching of upper and lower switching elements is controlled by respective upper and lower arm driving circuits. Those switching elements are connected in series across a primary d.c. power source and their successive switching generates a drive voltage which is applied to a load. A secondary d.c. power source is connected to the lower arm driving circuit while the upper arm driving circuit is connected to a capacitor connected to the high potential side of the primary d.c. power source. The capacitor is charged from the secondary d.c. power source through a charging circuit. This driving arrangement is particularly applicable to multi-phase driving circuits.

Driving circuit for a switching element including an improved power

An ON holding circuit is provided which outputs a signal which identifies an ON state of an insulated gate transistor to a gate voltage input circuit, and inhibits the gate voltage input circuit from being responsive to an input signal which identifies an OFF state of the insulated gate transistor when an overcurrent adjusting circuit operates continuously.

Drive circuit for an insulated gate transistor having overcurrent

A mathematical model for simulating a dynamic characteristic of an electric power supply apparatus, a model control function for controlling an output from the mathematical model in a closed loop fashion and an electric power supply apparatus control function for approximating a control variable for the electric power supply apparatus to a reference value are provided in a control circuit, wherein an output from the mathematical model is output as a pulse width reference signal, and the pulse width reference signal is corrected by an on-delay portion due to switching elements by means of a gain revision circuit, thereby promptly and stably controlling the electric power supply apparatus.

Circuit for controlling an electric power supply apparatus, a method

In order to provide miniaturization and increased-frequency operation of a DC-DC converter used with a computer, etc., a capacitor is connected in parallel with a switching element when the switching element is turned off to reduce turn-off loss. When the switching element is turned on, the capacitor and a DC power source are connected in series to supply the energy stored in the capacitor to a load circuit to result in a high initial voltage being applied across the load circuit.

DC-DC converter and a computer using the converter

The switching of the positive (or pullup power) and negative (or pulldown power) semiconductor elements, are controlled by driving circuits which are in turn controlled by level shift circuits which have a first current control circuit and a second current control circuit coupled in parallel and this parallel connection is coupled in series with the control N-channel MOSFET of a current mirror circuit in a circuit loop arrangement with a control power supply. The first and second current control circuits are responsive to first and second control pulses of pulse widths t.sub.1 and t.sub.1 +t.sub.2, in accordance with a driving signal such that the first current control circuit supplies a first current level to the control N-channel MOSFET during the first time period t.sub.1 and the second current control circuit supplies a second current level, smaller than that of the first current level, thereto for a predetermined time period t.sub.1 +t.sub.2 thereby resulting in a current flow through the controlled N-channel MOSFET of the current mirror circuit of a current value corresponding to the sum of the first and second current levels. The controlled N-channel MOSFET, providing ON/OFF control of a P channel MOSFET, is disposed in a second circuit loop which is powered by a high voltage power supply. This P-channel MOSFET, coupled to the high voltage power supply, supplies an output signal to a load in response to the current flowing through the controlled N-channel MOSFET.

Level shift circuit for controlling a driving circuit

A current sensing circuit for sensing a main current flowing through a power semiconductor element or elements, by utilizing a second current which is small in magnitude compared to the main current and varies depending on the main current, and sensing the second current through a current mirror circuit as a bias current of a differential circuit, and a function of sensing the temperature of the semiconductor element being afforded to the current sensing circuit through selection of a bias voltage.

Solid state current sensing circuit and protection circuit

A switching power supply using a step-up transformer whose impedance viewed from its primary side is different from the impedance viewed from its secondary side whereby the inductance of its primary and secondary windings are settable independently of each other.

Switching power supply

A reactive power compensator for an electric power system includes a voltage control circuit which amplifies a differential voltage between the potential command value and a potential signal corresponding to the voltage of the electric power system detected by a potential detector. The voltage control circuit outputs a reactive power compensation control signal. The control signal is fed to a reactive power output circuit which controls the voltage of the power system in order to compensate for reactive power in the power system. A gain calculation circuit is provided for setting the gain of the voltage control circuit to a value proportional to the level of short-circuit capacity of the system power on the system power supply side of the reactive power output circuit.

Reactive power compensator for electric power system

A monolithic integrated circuit device comprises first and second output terminals, a power switching circuit which is connected across the first and second output terminals and through which electric current is supplied to an external load from an external power source, a driving a circuit for generating a first drive signal to be supplied to the power switching circuit, and a third output terminal in electrical connection with the driving circuit for derivation of electric energy from the driving circuit as a second drive signal to be spplied to an external circuit via the third output terminal. The monolithic integrated circuit device is capable of not only controlling power supply to an external load but also driving an external circuit which may be another power switching cirtcuit cooperative with the power switching circuit in the present monolithic integrated circuit device for the purpose of controlled power supply to the external load or which may be other types of electronic circuits.

Monolithic integrated circuit device

In a power conversion system, a DC voltage of a DC power supply is converted into a predetermined high-frequency voltage by an inverter, and a high-frequency low voltage generated from the inverter is converted into a high-frequency high voltage by a transformer. A high-frequency high voltage generated from a secondary winding of the transformer is converted into a predetermined low-frequency voltage by a frequency changing circuit. The commutating operation of the frequency changing circuit is performed by a control circuit in response to the output current of the frequency changing circuit and in synchronism with the starting time of the short-circuiting prevention period of the inverter. As a result, the converted output of the power conversion system is prevented from decreasing.

Pulse width modulated inverter with high-to-low frequency output

In a voltage resonance type switching power source apparatus, which has a step-up transformer, a resonance capacitor connected in series with a primary winding of the transformer, and a transistor connected in parallel with the capacitor to cause a resonant oscillation current by the on-off operation thereof, an on signal of the transistor is produced in synchronism with a second signal, which is obtained by delaying a first signal depending on a voltage induced in a detecting winding provided in the transformer by a predetermined delay time.

Voltage resonance type switching power source apparatus

An impedance for short-circuit prevention is connected with a secondary winding side of a transformer of a resonant converter comprising a resonant circuit, a D.C. input source, and a switching devices. The short-circuit prevention impedance is driven by the driving current generated in a driving winding in accordance with a resonance current at the primary winding side of the transformer, thereby obviating the stop of an oscillation. The oscillation can be stopped at a timing of not generating a surge voltage in the switching devices by detecting a current returning to the D.C. input power source.

Resonant converter for stabilized operation of switching devices

A power conversion apparatus comprises an inverter for converting a voltage of a DC power source into AC power having a frequency higher than the commercial frequency, a transformer, fed by the inverter, for outputting AC power, which is adjusted at a desired voltage, a frequency converter, formed by two pairs of two gate turn-off thyristors (GTOs) connected in reverse-parallel, for converting the frequency of the AC power supplied from the transformer into the commercial frequency, and an energy regenerating device having capacitors for absorbing the energy of a spike voltage occurring due to a circuit inductance upon interruption of a current of each GTO of the frequency converter and a bridge circuit, formed by GTOs and diodes connected in reverse-paralel therewith, for switching over the direction of connecting the capacitors with a secondary winding of the transformer in accordance with the polarity of a voltage of the secondary winding in such a manner that the energy stored in the capacitors is regenerated to the transformer.

Current and frequency converter having means to reduce switching losses

Growing community of inventors

Hitachi, Japan

Yasuo Matsuda