Mitsubishi Electric Corporation

Mitsubishi Denki Kabushiki Kaisha

Makoto Seto

Masaki Yamada

Akihiko Iwata

Shigeki Harada

Takashi Kumagai

Noriyuki Matsubara

Hiroshi Ito

Ikuro Suga

Kenro Mitsuda

Sadayuki Matsumoto

Tomoyuki Kawakami

Naoki Ochi

Yoshiyuki Takuma

Sadanari Yano

Kimihiro Yanagihara

Yukio Todoroki

In a power conversion apparatus that boosts a solar light voltage, converts it to AC and supplies AC power to a load or system, power loss is reduced and efficiency is improved. An inverter unit, in which AC sides of three single-phase inverters receive DC power from respective sources with a voltage ratio of 1:3:9 as respective inputs are connected in series. Gradational output voltage control of an output voltage is carried out using the sum of the respective generated AC voltages. Also, a solar light voltage is boosted by a chopper circuit to generate the highest voltage DC power source. When the solar light voltage exceeds a predetermined voltage, the boosting of the chopper circuit is stopped, thereby reducing power loss due to the boosting.

Power conversion apparatus

Provided is an electric double layer capacitor including a large capacity single cell having a large electrostatic capacity and a small capacity single cell are connected to the same exterior case in parallel, and a thickness of a separator of the large capacity single cell is made thicker than a thickness of a separator of the small capacity single cell. With this structure, a supply amount of an electrolyte solution to the large capacity single cell is markedly increased compared with the small capacity single cell, thereby being capable of preventing degradation of the large capacity single cells and the small capacity single cells and providing the electric double layer capacitor having an excellent cycle life and having a large power storage amount while keeping characteristics capable of instantaneously allowing large current to flow.

Electric double layer capacitor

In a power conversion apparatus that boosts a solar light voltage, converts it to AC and supplies AC power to a load or system, a second inverter is connected in series to one of two terminals on the AC side of a first inverter that uses, as its DC source, a DC voltage boosted from a solar light voltage by a chopper circuit. A third inverter is connected in series to the other terminal. Then, output voltages of the second and third inverters are controlled to be equal, and an output voltage is provided by using the sum of the generated voltages of the first, second, and third inverters. Thus, a mid-point potential of the DC power source is made equivalent to an intermediate potential of the output voltage of the power conversion apparatus, that is, the mid-point potential (ground potential) of a system.

A power conversion apparatus includes a first single-phase inverter that uses as a DC power source a first DC voltage that is boosted from a solar light voltage by a boosting chopper circuit. The first single-phase inverter is arranged between two single-phase inverters that use second DC power sources that are supplied from the first DC power source. AC sides of the respective single-phase inverters are connected in series. A power conditioner thus configured provides an output voltage using the sum of the generated voltages of the respective single-phase inverters. Chopper circuits are connected between the first DC power source and the second DC power sources, and power is supplied to the second DC power sources from the first DC power source via switching devices in the single-phase inverters.

The present invention relates to a device for driving an induction motor comprising:

Device for driving an induction motor

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Tokyo, Japan

Makoto Seto