Hitachi, Ltd.

Youji Takahashi

Kiyoshi Nakamura

Akira Kimura

Atsushi Abe

Kiyoshi Nakata

Yoshio Tsutsui

Shigeyoshi Koike

Toyoharu Uchiyama

Koumei Miyairi

A power conversion system is disclosed in which a direct current is taken out of an AC power supply of variable frequency and variable voltage through a PWM converter in such a manner that in a region of low source voltage, the converter input current is limited to a predetermined value to maximize the DC power taking the voltage drop of the power supply into consideration with the power factor of '1' of the power supply, and when the current reaches an allowable maximum, it is limited to that value. In a region of high source voltage, on the other hand, the quadrature component of the input voltage applied to the source voltage is controlled preferentially in a manner to control the converter input voltage below a predetermined value, thus making it possible to secure the maximum power available from the converter over the entire range of operation. If a battery is connected to the DC side, a cooperative operation is made possible while the battery is charged properly.

Power conversion system

A power supply system for a linear motor type transportation system includes a series of driving coils disposed along a railroad track for producing a moving magnetic field to drive a train, a plurality of feeding blocks disposed along the railroad track for supplying electric power to the series of driving coils, a plurality of power converters each connected to the corresponding feeding blocks to supply electric power to each corresponding feeding section composed of the feeding blocks, and a plurality of block switches connected between neighboring two feeding blocks of the feeding blocks. Each of main controllers for determining each feeding section includes a boundary candidate operation unit for calculating a feeding section boundary candidate of a power converter between the neighboring power converters on the basis of the position information of a train being present in the feeding section, a section boundary determining unit, and a feeding block switch control unit for controlling on-off states of the block switches so as to define the feeding section boundary between neighboring two feeding blocks. Each boundary determining unit selects one boundary from two boundary candidates supplied from the boundary candidate operation units of the main controller of the neighboring two power converters.

Power supply system for a linear motor type transportation system

Growing community of inventors

Katsuta, Japan

Youji Takahashi