Motor control device

Claim 2

A motor control device including a 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.

Claim 3

The motor control device according to claim 1 , further comprising: a setting unit that sets a pulse width in said PWM pattern generating unit to an integral multiple of a pulse width (PWM) period and makes a set value of said integral multiple variable with time.

Claim 4

A motor control device including a 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 current control unit that manipulates a d axis voltage instruction and q axis voltage instruction of said inverter output such that an actual values of said d axis current and q axis current (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) of said motor track a current instruction value; a PWM pattern generating unit that calculates and outputs a PWM pattern such as to superimpose on said d axis voltage instruction and q axis voltage instruction a d axis positive/negative pulse of a same period as a period of pulse width modulation (PWM) of said inverter in an inferred d axis direction found from an inferred position value of said motor rotor, using said inferred position value of said motor rotor and the d axis voltage instruction and q axis voltage instruction which are output from said current control unit; a current co-ordinate conversion unit that, using said inferred position value of said motor rotor converts a three-phase current of said motor to actual values of said d axis current and q axis current, which are values on d and q co-ordinate axes; a d and q axis rate of current change calculating unit that respectively calculate and output rates of change with time of 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 a PWM pattern which is output from said PWM pattern generating unit and 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.

Claim 5

A motor control device including a 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 current control unit that manipulates a d axis voltage instruction and q axis voltage instruction of said inverter output such that an actual values of said d axis current and q axis current (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) of said motor track a current instruction value; a PWM pattern generating unit that calculates and outputs a PWM pattern such as to superimpose on said d axis voltage instruction and q axis voltage instruction a d axis positive/negative pulse of a same period as a period of pulse width modulation (PWM) of said inverter in an inferred d axis direction found from an inferred position value of said motor rotor, using said inferred position value of said motor rotor and the d axis voltage instruction and q axis voltage instruction which are output from said current control unit; a current co-ordinate conversion unit that, using said inferred position value of said motor rotor converts a three-phase current of said motor to actual values of said d axis current and q axis current, which are values on d and q co-ordinate axes; a d and q axis rate of current change calculating unit that respectively calculate and output rates of change with time of 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 a PWM pattern which is output from said PWM pattern generating unit and 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.

Claim 6

The motor control device according to claim 3 , wherein said motor rotor position inferring unit comprises an evaluation variable calculating unit that inputs a rate of change of said q axis current which is output from said d and q axis rate of current change calculating unit and outputs difference of a rate of change of q axis current at positive and negative time-points of a d axis positive/negative pulse that is superimposed by said PWM pattern generating unit as an evaluation variable; and a motor rotor position inferring unit that performs a corrective calculation on said motor rotor position such that said evaluation variable which is output from said evaluation variable calculating unit is zero.

Claim 7

A motor control device according to claim 4 , wherein, when said motor control device is applied to a permanent magnet type reluctance motor, said motor control device outputs, as a value obtained by adding a value that has been stored beforehand taking into account said permanent magnet type reluctance motor rotor magnetic saturation characteristic in accordance with said current instruction value to a difference of a rate of change of a q axis current at positive and negative time-points of said d axis positive/negative pulse superimposed by said PWM pattern generating unit, an evaluation variable calculated by said evaluation variable calculating unit, which is a constituent element of said motor rotor position inferring unit.

Claim 8

The motor control device according to claim 3 , further comprising: a d axis current addition and averaging unit that inputs actual values of a d axis current that are output from said current co-ordinate conversion unit and calculates and outputs average values during a PWM period based on a PWM pattern that is output from said PWM pattern generating unit; and a q axis current addition and averaging unit that inputs actual values of a q axis current that are output from said current co-ordinate conversion unit and calculates and outputs average values during a PWM period based on a PWM pattern that is output from said PWM pattern generating unit, wherein said d axis current and averaging unit and said q axis current addition and averaging unit respectively input outputs of said d axis current addition and averaging unit and said q axis current addition and averaging unit to said current control unit.

Claim 9

The motor control device according to claim 3 , wherein said current control unit operates only during a time of separation in synchronization with a PWM period based on a PWM pattern that is output from said PWM pattern generating unit.

Claim 10

The motor control device according to claim 3 , wherein, when said motor control device is applied to a permanent magnet type reluctance motor, said motor control device variably sets an amplitude of a d axis positive/negative pulse which is superimposed by said PWM pattern generating unit to a value that has been stored beforehand taking into account said permanent magnet type reluctance motor rotor magnetic saturation characteristic in accordance with said current instruction value.