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Power conversion device

  • US 9,859,809 B2
  • Filed: 10/23/2015
  • Issued: 01/02/2018
  • Est. Priority Date: 10/23/2015
  • Status: Active Grant
First Claim
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1. A power conversion device comprising:

  • a first power-supply circuit unit includinga first converter to convert an AC voltage supplied from a power supply to a DC voltage,a first circuit unit in which a first switch and a first resistor are connected in parallel,a first capacitor to smooth a DC voltage supplied through the first circuit unit,a first inverter to convert a DC voltage smoothed by the first capacitor to an AC voltage, anda first control unit to control an opening operation and a closing operation of the first switch;

    a second power-supply circuit unit includinga second converter to convert an AC voltage supplied from the power supply to a DC voltage,a second circuit unit in which a second switch and a second resistor are connected in parallel,a second capacitor to smooth a DC voltage supplied through the second circuit unit,a second inverter to convert a DC voltage smoothed by the second capacitor to an AC voltage, anda second control unit to control an opening operation and a closing operation of the second switch; and

    a voltage detection unit to detect a voltage between ends of the first capacitor, or a voltage between ends of the second capacitor, whereina line, through which the first circuit unit and the first capacitor are connected, is connected to a line, through which the second circuit unit and the second capacitor are connected, and a line, through which the first converter and the first capacitor are connected, is connected to a line, through which the second converter and the second capacitor are connected,the first control unit outputs a closing-operation command signal to the first switch based on either a first closing time or a second closing time, whichever is later, where the first closing time is a time required for the first switch to transition to a closed state after the first control unit detects a first detection signal indicating that a voltage detected by the voltage detection unit exceeds a predetermined threshold value, and the second closing time is a time required for the second switch to transition to a closed state after the first detection signal is detected by the second control unit,the second control unit outputs a closing-operation command signal to the second switch based on either the first closing time or the second closing time, whichever is later,the first control unit outputs an opening-operation command signal to the first switch based on either a first opening time or a second opening time, whichever is later, where the first opening time is a time required for the first switch to transition to an opened state after the first control unit detects a second detection signal indicating that a voltage detected by the voltage detection unit is below a predetermined threshold value, and the second opening time is a time required for the second switch to transition to an opened state after the second detection signal is detected by the second control unit, andthe second control unit outputs an opening-operation command signal to the second switch based on either the first opening time or the second opening time, whichever is later.

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