Patent ID: 6580247
Filing Date: 2003-06-17
Classification: H02P

Abstract:
A motor control device includinga motor rotor having magnetically protruding polarity; an inverter that converts DC power to AC power; and a control unit that supplies an output from said inverter to said motor rotor, comprising: a PWM pattern generating unit that calculates and outputs a PWM pattern such as to output a pulse synchronized with a period of pulse width modulation (PWM) of said inverter and depending on an inferred position value of said motor rotor; a current co-ordinate conversion unit that, using said inferred position value of said motor rotor converts a three-phase current to actual values of a d axis current and q axis current, which are values on a d and q co-ordinate axes (q axis: direction of a protruding polarity of said motor rotor, d axis: direction at right angles to a direction of protruding polarity of said motor rotor); a d and q axis rate of current change calculating unit that respectively calculates and outputs rates of change with time of said d axis current and q axis current actual values, which are outputs from said current co-ordinate conversion unit, synchronized with a PWM pattern which is an output from said PWM pattern generating unit; and a motor rotor position inferring unit that infers and calculates a position of said motor rotor, using said PWM pattern which is output from said PWM pattern generating unit and said d axis rate of current change and q axis rate of current change which are output from said d and q axis rate of current change calculating unit and outputs a calculated value as an inferred position value of said motor rotor.