Fuji Electric Co., Ltd.

Fuji Electric Systems Co. Ltd.

Zhejiang University

Fuji Electric Fa Components & Systems Co., Ltd.

Yasuhiro Okuma

Nobuyuki Kobayashi

Kazuaki Mino

Dehong Xu

Hiroshi Yamamoto

Yi Chen

Osamu Hashimoto

Kazuo Kuroki

Hirokazu Tokuda

Yanjun Zhang

Xiao-feng Wu

Hiroyuki Matsuo

Zhiwei Wen

Xiaofeng Wu

An entirely integrated EMI filter is based on a flexible multi-layer strip material. An EE or EI core comprises two side pillars and one middle pillar and forms a closed magnetic circuit. The middle pillar has an air gap. A first winding and a second winding respectively are wound around the two side pillars in a same winding direction. The middle pillar is wound with a third winding and a fourth winding, or with only a fifth winding. Passive components (e.g., all passive components) of the EMI filter are integrated into one core so that in its differential mode, insertion loss is significantly reduced, the size and volume are reduced, and the distribution constant of the EMI filter has less impact on the filter's performance.

Entirely integrated EMI filter based on a flexible multi-layer strip material

An integrated structure of common-mode inductors and differential-mode capacitors in an EMI filter realized using a flexible circuit board, including: a closed magnetic circuit formed by a first magnetic core and a second magnetic core, optionally including an air gap formed in a middle pillar of the magnetic cores, and with a flexible printed circuit board (FPC) wound on at least one pillar, the FPC formed by laminating alternating insulating and copper foil layers. The integrated structure of inductors and capacitors is advantageous in reducing the volume of the EMI filter and improving the power density of an electronic power transformer.

EMI filter with an integrated structure of common-mode inductors and differential-mode capacitors realized by flexible printed circuit board

A power conversion apparatus includes serially connected arms U and X, serially connected arms V and Y, serially connected arms W and Z, and a capacitor, the pairs of serially connected arms and the capacitor all connected in parallel to one another. The input-side arms U and X and the output-side arms W and Z are subjected to PWM control so that the arms W and Z are controlled to have a voltage that is lower than that of the arms U and X, thereby providing a step down operation. A step up operation also can be provided by an opposite relation in which the arms W and Z are controlled to have a voltage that is higher than that of the arms U and X, thereby to expand the range within which the output voltage is controlled with the effect of reducing distortion.

Power conversion apparatus

A power-converting apparatus features the ability to achieve initial charging of a smoothing capacitor generating a minimum rush current by obviating the need for additional series connections in a battery, and also obviating the need for an initial charging circuit consisting of a charging resistor and switch in the capacitor. The power-converting apparatus includes a separating device that electrically separates an AC power-supply source from the input devices of the power-converting apparatus, an AC/AC converting circuit that initially rectifies AC current from an AC power-supply source and then causes a capacitor to smooth the rectified AC current, thereby converting the rectified AC current into DC current before again converting the DC current into AC current, a battery; and a DC/DC converting circuit that enables a capacitor to be charged with DC voltage delivered from the battery, and conversely enables the battery to be charged with a DC voltage delivered from the above capacitor bilaterally or unilaterally.

Starting circuit for power-converting apparatus

An electric power converting device can supply a constant voltage to a load while suppressing voltage variation in the AC power source, to reduce breakdown voltages of semiconductor switching elements. The device includes first to third switching element series circuits and at least a first capacitor connected in parallel. One end of the AC power source and one end of the load are connected to each other. Second and third capacitors are connected in parallel to the AC power source side and the load side, respectively. The one end of the power source is connected to a series connection point of the first switching element series circuit through a reactor, the other end of the power source is connected to a series connection point of the second switching element series circuit, and the other end of the load is connected to a series connection point of the third switching element series circuit through another reactor. Change in the power source voltage is compensated by a series converter, which is formed by the second and third switching element series circuits, and change in voltage of the capacitor due to the compensating operation is compensated by charging and discharging operation by a parallel converter formed by the first and second switching element series circuits.

Electric power converting device

The electric power converter includes a series converter connected in series between an AC power supplyand a loadand having capacitorsas a power supply for the converter, switching devices, and diodes; and a parallel converter connected in parallel to the AC power supplyand having the capacitors, switching devicesand diodes. The series converter compensate the change in the voltage of the AC power supplyto feed a certain voltage to the load, and the parallel converter conducts charging and discharging operations to compensate the changes in the voltages of the capacitorsandcaused by the compensating operations of the series converter. The converter suppresses the change of the AC power supply voltage and feeds a certain voltage to the load at a high efficiency and low running costs.

Power converter

A voltage amplitude adjuster including semiconductor switches for power conversion, an AC chopper for converting an input AC voltage to an AC voltage of the same phase and different amplitude relative to the input AC voltage, and a smoothing AC filter for providing a clear signal to a primary winding of a transformer. Further, by providing a wattmeter, the saved power can be displayed.

Growing community of inventors

Tokyo, Japan

Yasuhiro Okuma