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Method for measuring phase current for inverter control apparatus using single current sensor and apparatus therefor

  • US 20020167300A1
  • Filed: 05/08/2002
  • Published: 11/14/2002
  • Est. Priority Date: 05/10/2001
  • Status: Active Grant
First Claim
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1. A method for measuring current of each phase for an inverter control apparatus comprising a converter for converting alternating current from a three-phase alternating current power source into direct current, an inverter provided with a pair of switching devices in each phase, the inverter for converting direct current from the converter into alternating current and providing the alternating current to a three-phases induction motor, single current sensor for measuring current of a phase, which flows through the motor, an analog-to digital (A/D) converter for converting an analog measured value of current, which is measured by the current sensor, into a digital measured value, and an inverter controller for generating a reference voltage of each phase and a pulse width modulation (PWM) signal using a triangle wave on the basis of the digital measured value from the analog digital converter, to thus control switching of a is switching device of each phase, the method comprising the steps of:

  • (a) changing the reference voltages of arbitrary two phases in one cycle of the triangle wave;

    (b) measuring current of each phase for the one cycle of the triangle wave using the current sensor; and

    (c) compensating for the amount of change in the reference voltages of the two phases in the one cycle of the triangle wave.

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