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POWER CONVERSION DEVICE

  • US 20160204691A1
  • Filed: 07/04/2014
  • Published: 07/14/2016
  • Est. Priority Date: 09/02/2013
  • Status: Active Grant
First Claim
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1. A power conversion device comprising:

  • a power conversion circuit for converting DC power supplied from a DC power supply to AC power; and

    a power conversion control section for controlling operation of the power conversion circuit so as to generate autonomous operation power as an AC voltage source in a parallel-off state from a power grid, whereinthe power conversion circuit includes;

    a DC-DC power conversion circuit for converting DC voltage of the DC power supply to DC link voltage; and

    a DC-AC power conversion circuit for converting the DC link voltage to AC voltage, andthe power conversion control section includes;

    an AC voltage control section for controlling the AC voltage of the DC-AC power conversion circuit;

    an AC current suppression section for limiting AC current of the DC-AC power conversion circuit to a predetermined current limit value or smaller;

    a DC voltage shortage suppression section for, when the DC link voltage of the power conversion circuit reduces, in response to the reduction, reducing the current limit value to be given to the AC current suppression section;

    a protection circuit for stopping operation of the power conversion circuit when at least one of the following conditions is satisfied;

    the AC current suppression section has continued operation of limiting the AC current to the current limit value or smaller for a predetermined time or longer;

    a state in which an AC voltage effective value obtained based on an AC voltage detection value detected by a voltage detection circuit which detects AC voltage outputted from the power conversion circuit is equal to or smaller than a predetermined threshold voltage, has continued for a predetermined time or longer; and

    a state in which a difference voltage between an AC voltage command value generated by the AC voltage control section and an AC voltage instantaneous value obtained based on the AC voltage detection value detected by the voltage detection circuit which detects the AC voltage outputted from the power conversion circuit is equal to or greater than a predetermined threshold voltage, has continued for a predetermined time or longer.

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