Daikin Industries, Ltd.

Eiji Tooyama

Morimitsu Sekimoto

Takurou Ogawa

Toshiyuki Maeda

Tomoisa Taniguchi

Nobuo Hayashi

Akiko Sera

The voltage detection circuit () is a voltage divider circuit including a plurality of resistances (toandto) and detects voltages (Vac, Vac) correlating with a power source voltage (Vin) of the AC power source (). The calculation unit () obtains the across voltage (VL) of the reactor () using detection results (Vac, Vac) of the voltage detection circuit (), and estimates a power source current (Iin) based on the across voltage (VL). The calculation unit () corrects gains of the detection results (Vac, Vac) so that a value correlating with an average value per predetermined time period of the estimated power source current (Iin) matches a value correlating with an average value per the predetermined time period of a current (Iinv) downstream of the capacitor (), and obtains the across voltage (VL) using the detection results (Vac, Vac).

Current estimating device

Disclosed herein is a power conversion device including a storage and a power conversion controller. The storage stores multiple values, each correlated to a disturbance that causes distortion in a current to a power converter, in association with a phase angle of a voltage of an AC power supply. The power conversion controller controls ON/OFF operations by using the values stored in the storage to compensate for a manipulated variable of control performed by the power converter in association with the phase angle of the voltage of the AC power supply.

Power conversion device with reduced current deviation

A power conversion apparatus is equipped with switching devices to perform power conversion of input AC power supplied from an AC power supply to output AC power having a predetermined voltage and a predetermined frequency, and to supply the power to a motor connected thereto. The apparatus includes a controller controlling switching of the switching devices, a capacitor smoothing a ripple generated by the switching of the switching devices, a current controller controlling a current flowing to the motor, and a voltage distortion corrector detecting a harmonic component caused by distortion in motor input power, and superimposing compensation values on an output of the current controller in accordance with a value of the harmonic component.

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Osaka, Japan

Eiji Tooyama