Fuji Electric Co., Ltd.

Tokyo Institute of Technology

Fuji Electric Device Technology Co., Ltd.

Fuji Electrical Co., Ltd.

Seiki Igarashi

Akio Suzuki

Masafumi Tabata

Shin Soyano

Susumu Iwamoto

Satoki Takizawa

Shoichi Furuhata

Ryuichi Shimada

Toshifusa Yamada

Masaki Hirakata

Manabu Watanabe

Taichi Tanigawa

Naotaka Matsuda

Hideaki Kakiki

Yoshiyuki Uchida

Naoto Fujisawa

Etsuo Arai

A driving apparatus includes: a driving section configured to drive a control terminal of a semiconductor device according to a control signal input from an outside, the semiconductor device including a first main terminal, a second main terminal, and the control terminal that is configured to control a connection state between the first main terminal and the second main terminal that are connected in parallel with a snubber; and a drive control section configured to lower a drive capability of the driving section during a period in which an inter-main-terminal voltage between the first main terminal and the second main terminal changes by a predetermined reference voltage difference owing to switching of the semiconductor device, compared with other at least some periods.

Driving apparatus, semiconductor apparatus, and driving method

A semiconductor device of the present invention suppresses high frequency noise caused in a semiconductor device incorporating SiC elements. The semiconductor device includes semiconductor elements connected in series, a SiC diode element connected in parallel to the semiconductor element, and an oscillation suppressing circuit being connected in parallel to the semiconductor element and the SiC diode element and suppressing voltage fluctuation caused in the SiC diode element in response to turn-ons of the semiconductor element. The oscillation suppressing circuit suppresses voltage fluctuation caused in the SiC diode element in response to turn-ons of the semiconductor element thereby improving reliability of the semiconductor device.

Semiconductor device and oscillation suppressing device

A system linking apparatus for generated electric power which may be made smaller and more efficient. The system linking apparatus is intended for connecting an electric power system to an output of a power generator through a linking inverter (PWM inverter). The system linking apparatus includes a magnetic energy regenerating circuit, a diode rectifier, and a capacitor. The magnetic energy regenerating circuit has a capacitor for condensing magnetic energy condensed in the power generator. The diode rectifier is connected with the magnetic energy regenerating circuit and operates to dc convert electric power generated by the power generator and output the converted power to the linking inverter. The capacitor is connected with the diode rectifier and operates to keep a dc output to the linking inverter at a predetermined voltage.

System linking apparatus for generated electric power

A switching power supply circuit reduces the capacity of the capacitor on the load side, reducing its size, weight, and cost. The switching power supply circuit has a pair of diodes connected in series, a pair of MOSFETs connected in series, a pair of capacitors connected in series, a snubber capacitor connected in parallel with the pair of diodes, the pair of MOSFETS, and the pair of capacitors. The circuit can include a pair of additional capacitors, connected respectively in parallel with the MOSFETS, to allow the MOSFETs to execute a zero-voltage switching. The circuit also includes an AC input terminal connected to the mutual connection point of the pair of diodes, a transformer including a primary winding having one end connected to the mutual connection point of the pair of MOSFETS, and the other end connected to the mutual connection point of the pair of capacitors. The primary winding has a center tap connected to another AC input terminal.

Switching power supply circuit

An electric power conversion apparatus includes a noise reduction device for reducing the common mode noise and the normal mode noise caused by on/off of the switching devices of an electric power conversion apparatus for driving an AC motor. Since the noise-compensation-current supply circuit of the noise reduction device uses devices with a lower breakdown voltage, the operating speed of the noise-compensation-current supply circuit is higher than the operating speed of the conventional noise-compensation-current supply circuit which uses devices with a higher breakdown voltage equivalent to the DC voltage of the electric power conversion apparatus.

Electric power conversion apparatus with noise reduction device

A switching power supply uses zero-current and zero-voltage switching to reduce switching noise. A main switch and an auxiliary switch channel current and voltage between various component paths to maintain a DC output voltage while switching at zero-current or zero-voltage states. Switch ON-OFF time ratios are controlled with a simple scheme to improve the circuit power factor. The switching rate is set to arbitrary frequencies, with switch ON time and OFF time being controlled independently. Losses in efficiency when driving a load substantially less than the rated load are avoided. The switches and control functions can be implemented on an integrated circuit.

Switching power supply using an input DC power supply

A circuit accurately detects an arm voltage pulse from an inverter that is used for on-delay compensation. Specifically, switching elements S,to S,are provided with detection circuits C,to C,, respectively, for detecting an on or off state of a corresponding inverter arm in order to detect an arm voltage pulse from the inverter accurately and without delay. Since outputs from the detection circuits C,, C,, C,on an upper arm have an excessively high voltage level before processing, level-down circuits Dw,, Dw,, Dw,reduce these outputs down to an appropriate voltage level for signals used by a control circuit. The outputs are then provided to an on-delay compensator in the control circuit.

On-delay-compensating arm on-detection circuit

A switching power supply for outputting an isolated DC voltage includes a transformer TR1 having a secondary winding N21 and a tertiary winding N3; a semiconductor switch Q1; a DC voltage source (capacitor) C1 connected to the transformer TR1 and the semiconductor switch Q1; a rectifier D1 connected to the secondary winding N21; a power IC, the power supply voltage for which is obtained by rectifying the output of the tertiary winding N3 of the transformer TR1; and a comparator IC5 for detecting the voltage of the control power supply that is lower than a predetermined value, by which to shift to the power saving mode of operation. The above configuration eliminates the photo-coupler for transmitting the power saving signal and reduces the number of terminals of the power IC.

Switching power supply

A switching power supply for achieving a high power factor includes a rectifier Rect 1, a DC voltage source (capacitor) C1, a transformer TR1, a diode D6; a diode D7 a semiconductor switch Q1, and a inductor L1. The DC voltage source C1 is connected to an AC power supply AC via the rectifier Rect1. The transformer TR1 includes a primary winding N1, a secondary winding N2 and a tertiary winding N3. The transformer TR1 and the semiconductor switch Q1 are used to output an insulated DC voltage from the DC voltage source C1. The tertiary winding N3 is between the output of the rectifier Rect1 and the DC voltage source C1. The diodes D6 and D7 are connected to the respective input terminals of an AC power supply. The inductor L1 is connected between the output of the diodes D6, D7 and the semiconductor switch Q.

Switching power supply with power factor control

A switching power supply uses zero-current and zero-voltage switching to reduce switching noise. A main switch and an auxiliary switch channel current and voltage between various component paths to maintain a DC output voltage while switching in zero-current or zero-voltage states. Switch ON-OFF time ratios are controlled with a simple scheme to improve the circuit power factor. The switching rate can be set to arbitrary frequencies, with switch ON time and OFF time being controlled independently. This scheme permits efficient driving of a load that is substantially less than the rated load, as generally found in portable TV circuits. The switches and control functions can be implemented on an integrated circuit.

Variable frequency soft switching power supply with reduced noise and

A current detector includes a chopper circuit composed of a switching circuit, i.e. an inverse-parallel circuit composed of an insulated gate bipolar transistor IGBT and a diode, and a switching circuit, i.e. an inverse-parallel circuit composed of an IGBT and a diode, which are connected in series. When the diode on the opposite arm is turned on, a reverse recovery current is detected and its output is directed to a gate drive circuit via an insulating circuit. A switch in the gate drive circuit is opened to increase resistance, in order to reduce the speed at which the gate of the switching device is charged. Thus, the surge voltage and its increase ratio are reduced without reducing a switching speed or requiring a snubber circuit.

Gate drive circuit for power converters that reduces surge voltages

A balancing circuit balances the steady-state currents of the switching devices in an electric power converter, which facilitates reducing the size of the power converter and precisely balancing the steady-state currents. The balancing circuit holds transient sensing voltages at the time of turning-on of the switching devices, and detects the unbalance between the currents of the switching devices based on the distribution or unbalance of the sensing voltages by comparing the steady-state sensing voltages or the values corresponding to the steady-state sensing voltages with the stored transient sensing voltages. The steady-state currents of the switching devices are balanced by regulating the drive voltages of the switching devices based on the detected distribution of the steady-state currents.

Circuit for balancing steady-state currents of switching devices in

In packaged bridge circuit modules with power switching transistors such as IGBT's, internal wiring inductance can cause switching voltage spikes and imbalance between switching transistors. Upon inclusion of suitably arranged and configured inductance elements, internal wiring inductance can produce a counter-electromotive force during switching. To this end, an internal connecting terminal may branch from an output terminal, a bridge-shaped internal connecting terminal may be connected between an emitter circuit pattern of one power transistor and a collector circuit pattern of another power transistor, or signal terminals as auxiliary emitter terminals of two power transistors may be connected to an inductance providing region in a current path of an emitter circuit pattern.

Power transistor module wiring structure

In a switching transistor control circuit, the switching transistor has a control electrode and first and second main circuit electrodes. A reactor is connected in series with the first main circuit electrode of the switching transistor to receive a main circuit current through the switching transistor. Circuitry is connected to an end of the reactor remote from the first main electrode and to the control electrode of the switching transistor, for supplying an electromotive force to the control electrode which is generated by the reactor as main circuit current decreases when the switching transistor is turned off. A control electrode driving circuit is connected to the control electrode, and is connected to one of the first main circuit electrode and a predetermined intermediate position on the reactor, for supplying a drive signal to the control electrode for selectively turning the switching transistor on and off.

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Saitama, Japan

Seiki Igarashi