Patent ID: 6577096
Filing Date: 2003-06-10
Classification: H02P

Abstract:
A sensorless vector control system of an induction motor in which power is supplied from a power supply unit to drive an induction motor, comprising:a magnetic flux and speed controlling unit for receiving a predetermined command value and generating two phase voltages of direct current component; a first coordinate converting unit for converting the two phase voltages of direct current component into three phase voltages of alternate current component; an inverter for receiving the three phase voltages of alternate current component and driving an induction motor; a current detecting unit for detecting and outputting three phase currents of alternate current component flowing between the inverter and the induction motor; a second coordinate converting unit for converting the three phase currents of alternate current component from the current detecting means into two phase currents of direct current component; a magnetic flux and speed estimating unit for receiving the two phase voltage of DC component from the second coordinate converting unit and estimating values of magnetic flux and speed required for a vector control; and a primary resistance estimating unit for receiving the two phase voltages of direct current component, the two phase currents of direct current component and the magnetic flux and speed estimated values, estimating a primary resistance wherein the magnetic flux and speed controlling means comprises: a first operator for receiving a reference velocity (&ohgr;r*) and an estimated velocity ({circumflex over (&ohgr;)}r) and arithmetically operating; a speed controller for receiving the output of the first operator and outputting a reference torque component current (iqse*); a second operator for receiving the reference torque component current (iqse*) and the torque component current (iqse) on a synchronous reference frame and arithmetically operating; a torque current controller for receiving the output of the second operator and generating a q-axis voltage (vqse*) on the synchronous reference frame; a third operator for receiving the reference magnetic flux (&lgr;dre*) and the estimated magnetic flux ({circumflex over (&lgr;)}dre) of the induction motor, and arithmetically operating; a magnetic flux controller for receiving the output of the third operator and outputting an magnetic flux component offset current (idsâ€”offsete*); a magnetic flux current operator for receiving the reference magnetic flux (&lgr;dre*) of the induction motor and outputting a initial magnetic flux component current (idsâ€”inite*); a fourth operator for receiving the magnetic flux component offset current (idsâ€”inite*) and the initial magnetic flux component current (idsâ€”inite*) and operating them; a fifth operator for receiving the output value (idse*) of the fourth operator and the magnetic flux component current (idse) on the synchronous reference frame; and a magnetic flux current controller for receiving the output of the fifth operator and generating a d-axis voltage (vdse*) on the synchronous reference frame.