Fuji Electric Co., Ltd.

Makoto Yatsu

Satoki Takizawa

Kazuo Kuroki

Kazuyuki Yoda

In some aspects, a direct current power source, formed of a series connection circuit of single power sources, which has three mutually different voltage levels including zero can be provided with first, second, third, and fourth arm pairs, each configured by connecting two arms formed of semiconductor switches in series, an alternating current switch configured by combining semiconductor switches. As such, a plurality of voltage levels can be to be selected from and output by an on and off control of these switch elements.

Multilevel converter circuit for generating a plurality of voltage levels

Aspects of the invention are directed to a multilevel power converter the includes a DC power supply assembly having a positive terminal, a negative terminal, and a zero terminal; a first semiconductor switch series circuit composed of first through sixth semiconductor switches connected in series between the positive terminal and the negative terminal. The converter can include a second semiconductor switch series circuit composed of a first bidirectional switch, seventh and eighth semiconductor switches, and a second bidirectional switch connected in series between the connection point of the first and second semiconductor switches and the connection point of the fifth and sixth semiconductor switches, a first capacitor connected in parallel with a series circuit of the third and fourth semiconductor switches and a second capacitor connected in parallel with the second semiconductor switch series circuit.

Multilevel power converter

In some aspects of the invention, a power semiconductor module is applied to a multi-level converter circuit with three or more levels of voltage waveform. A first IGBT, a diode whose cathode is connected to the emitter of the first IGBT, and a second IGBT having reverse blocking voltage whose emitter is connected to the emitter of the first IGBT, are housed in one package, and each of the collector of the first IGBT, the collector of the second IGBT, the connection point of the emitter of the first IGBT and the emitter of the second IGBT, and the anode of the diode, is an external terminal.

Power semiconductor device and power conversion system using the device

An AC current source circuit converts a DC input voltage into an AC output current, and comprises a chopper circuit for converting a DC input voltage into a chopper voltage; and an inverter for converting the chopper voltage into an output AC current of a predetermined frequency. The inverter comprises at least four switch elements, and clamp-type snubber circuits corresponding to each of the switch elements are provided. The snubber circuit releases electric charges to the input terminal of the DC input voltage of the chopper circuit. The chopper circuit is connected to the inverter through a DC reactor. The DC input voltage is converted into a DC current by the chopper circuit and the DC reactor and transmitted to the inverter.

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Akiruno, Japan

Makoto Yatsu