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Current-limit system for voltage-type inverter

  • US 5,285,145 A
  • Filed: 04/24/1990
  • Issued: 02/08/1994
  • Est. Priority Date: 08/30/1988
  • Status: Expired due to Fees
First Claim
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1. A current limit system for use in a voltage-type inverter comprising:

  • first means for detecting the magnitude of an output current vector of the voltage-type inverter to determine if the magnitude exceeds a predetermined limit value, said first means including;

    detecting means for detecting the output currents of said voltage-type inverter; and

    comparator means for comparing said output currents detected by said detecting means with said predetermined limit value;

    second mans for determining the location of said output current vector;

    sixth means for determining the location of the counterelectromotive force vector of a load of said voltage-type inverter according to the output current and output voltage of said voltage-type inverter; and

    seventh means for selecting a voltage vector which reduces said output current in such a way that the rate of reduction of said output current is minimized on the basis of the locations of said output current vector and counter electromotive force vector, and for enabling said voltage-type inverter to produce said selected voltage vector as the output, when the magnitude of said output current vector exceeds its limit value, said seventh means including;

    determination means for determining the location of said output current vector and for providing a rotation angle signal that specifies the amount of rotation necessary for the counter-electromotive force vector to rotate with regard to the determined location of said output current vector;

    counter-electromotive force vector determination means for determining the location of said counter-electromotive force vector according to said counter-electromotive force vector provided by said sixth means and said rotation angle signal provided by said determining means; and

    output pattern generating means for producing one of the predetermined switching patterns in response to said rotation angle signal and said determination output from said counter-electromotive force vector determination means.

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