Kabushiki Kaisha Yaskawa Denki

Other

Yaskawa America, Inc.

Taisuke Katayama

Satoshi Watanabe

Eiji Yamamoto

Hiroshi Takagi

Kenji Mitsuda

Takashi Tanaka

Ryuji Suenaga

Kazuhiro Umeo

Thomas Bryan Sasada

A power conversion device includes three inverters configured to convert DC power of DC buses into single-phase AC power, and a controller configured to control the three inverters so as to generate three-phase AC power. The controller is configured to generate a fundamental wave command for generating one-phase AC power constituting the three-phase AC power, and to generate an adjustment wave command having triple the frequency of the fundamental wave command. Additionally, the controller is configured to output a phase voltage command, in which the adjustment wave command is superimposed on the fundamental wave command, and to determine an initial phase of the adjustment wave command to be offset from an initial phase of the fundamental wave command so as to reduce a voltage ripple occurring in the DC buses at double the frequency of the fundamental wave command.

Power conversion device and power conversion method

An inverter system includes an inverter apparatus and a smoothing capacitor charging-power apparatus. The inverter apparatus includes a transformer and an inverter cell. The transformer includes primary windings and secondary windings. Each of the inverter cells includes a converter circuit, a smoothing capacitor, and an inverter circuit. The converter circuit is configured to convert an intermediate alternating-current voltage to a direct-current voltage. The smoothing capacitor is configured to smooth the direct-current voltage. The inverter circuit is configured to at least partially generate a phase voltage of a variable alternating-current voltage from the direct-current voltage smoothed by the smoothing capacitor. Electric power is to be supplied from a second power supply different from a first power supply to the smoothing capacitor charging-power apparatus. The smoothing capacitor charging-power apparatus is electrically connected to the primary windings to supply initial charging power to the smoothing capacitor via the primary windings and the secondary windings.

Inverter system, inverter apparatus, and method of controlling inverter system

A power converting apparatus is provided. The power converting apparatus includes a power converter configured to output a voltage to a load, and a controller configured to output a PWM signal which is generated in response to a voltage command to the power converter. The power converter includes a plurality of switching elements driven based on the PWM signal. The controller is configured to generate the PWM signal such that a first period during which a zero voltage is outputted and a second period during which a non-zero voltage is outputted are adjusted according to the voltage command. The controller is allowed to output the PWM signal which is set such that one first period and one or more second periods exist within an updating cycle of the voltage command, to the power converter.

Power converting apparatus, control device, and method for controlling power converting apparatus

A power conversion device according to an aspect of an embodiment includes a power conversion unit and a control unit. The power conversion unit includes N (N is an integer number not less than two) power converters that output voltages on the basis of base signals having the same period and phase differences equivalent to &#xbd;N of the period of the base signal. The control unit controls the N power converters by using &#xbd; of the period of the base signal as a control period and shifts each of control timings of the N power converters by the &#xbd;N of the period of the base signal.

Power conversion device

A series-connected multi-level power conversion device according to an aspect of embodiments includes a multi-winding transformer and a power conversion unit. The multi-winding transformer has a relationship that n secondary windings respectively connected to n single-phase power converters in the same output phase have a voltage phase difference of 60/n degrees and a relationship that the m secondary windings respectively connected to the m single-phase power converters corresponding to the m output phases have a voltage phase difference of 60/m degrees.

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Fukuoka, Japan

Taisuke Katayama