POWER CONVERSION DEVICE

To solve such a problem that when a power storage device reaches an over discharge region at the time of power running, the DC side voltage of an inverter device cannot be boosted, thus causing degradation of acceleration performance or deterioration of energy saving effect.SOLUTION: A power conversion device includes a power supply having three potentials by means of a DC power supply and a power storage device connected in series therewith, an inverter device having multiple current control means combining a current control element for conducting or blocking a current flowing in one direction, and a rectifier cell for conducting a current in the inverse direction of the current control element, and driving an AC motor by converting the DC power supplied from the power supply into three-phase AC power, and a control arrangement for controlling the inverter device and the power storage device. During power running of the AC motor driven with three-phase AC power, obtained by converting DC power from both DC power supply and power storage device, the control arrangement controls the power storage amount of the power storage device, so as to match the discharge amount of the power storage device during power running with the amount of charge predicted by operation of the AC motor in a prescribed period including the power running time.SELECTED DRAWING: Figure 3 【課題】力行時に蓄電装置が過放電領域に達すると、インバータ装置の直流側電圧を昇圧できず、加速性能の低下や省エネルギー効果の悪化を招く。【解決手段】電力変換装置は、直流電源および当該直流電源と直列に接続した蓄電装置により３つの電位を有する電源と、一方向に流れる電流を導通または遮断する電流制御素子および当該電流制御素子と逆方向に電流を導通させる整流素子を組み合わせた電流制御手段を複数個有し、電源から供給される直流電力を三相交流電力に変換して交流電動機を駆動するインバータ装置と、インバータ装置および蓄電装置を制御する制御装置とを備え、制御装置は、直流電源および蓄電装置の両方からの直流電力を変換した三相交流電力により駆動される交流電動機の力行運転時に、蓄電装置の蓄電量を制御して、力行運転時の蓄電装置の放電量と当該力行運転時を含む交流電動機の所定期間の運転により予測される充電量とを一致させる。【選択図】図３