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US 8,044,618 B2Granted
Control apparatus for AC motor
AssigneeHitachi, Ltd.
InventorsJunnosuke Nakatsugawa, Yoshitaka Iwaji, Kazuaki Tobari, Kiyoshi Sakamoto
Life of this patent
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Abstract
It is attained by being provided with a motor constant calculation unit for calculating electric constants of a motor, and by correcting setting values of electric constants defined on one of the axes of two orthogonal axes, by a functional expression using a state variable defined on the same axis, and by correcting them by a functional expression using a state variable defined on the other axis.
Claims14
A control apparatus for an AC motor comprising:
- an inverter for applying pulse width modulated voltage to an AC motor, and for driving said AC motor;
- a unit for detecting electric current of said AC motor;
- and
- a controller for adjusting pulse width modulated voltage, which said inverter outputs, and for driving said AC motor;
- wherein said controller is provided with a motor constant calculation unit for calculating electric constants of a motor, and
- said motor constant calculation unit corrects setting values of electric constants defined on one of the axes of two orthogonal axes, by using a state variable defined on the same axis, and also corrects them by using a state variable defined on the other axis, and uses said corrected electric constants for driving control of said AC motor.
3 more elements
A control apparatus for an AC motor comprising:
- an inverter for applying pulse width modulated voltage to an AC motor, and for driving said AC motor;
- a unit for detecting electric current of said AC motor;
- and
- a controller for adjusting pulse width modulated voltage, which said inverter outputs, and for driving said AC motor;
- wherein said controller is provided with a motor constant calculation unit for calculating electric constants of a motor, and
- said motor constant calculation unit corrects setting values of electric constants defined on one of the axes of two orthogonal axes, by using a state variable defined on the same axis, and corrects them by using a state variable defined on the other axis, and uses said corrected electric constants for driving control of said AC motor,
- and when said electric constants setting values are used as d-axis inductance Ld, and said Ld corrected by using d-axis electric current Id is used as Ld(Id), said motor constant calculation unit executes correction of Ld by q-axis electric current Iq, by using the equation of Ld(Id, Iq)=Ld(Id)−K×Iq×Iq, wherein K is a constant.
4 more elements
A control apparatus for an AC motor comprising:
- an inverter for applying pulse width modulated voltage to an AC motor, and for driving said AC motor;
- a unit for detecting electric current of said AC motor;
- and
- a controller for adjusting pulse width modulated voltage, which said inverter outputs, and for driving said AC motor;
- wherein said controller is provided with a motor constant calculation unit for calculating electric constants of a motor, and
- said motor constant calculation unit corrects setting values of electric constants defined on one of the axes of two orthogonal axes, by using a state variable defined on the same axis, and corrects them by using a state variable defined on the other axis, and uses said corrected electric constants for driving control of said AC motor
- and when said electric constants setting values are used as q-axis inductance Lq, and said Lq corrected by using q-axis electric current Iq is used as Lq(Iq), said motor constant calculation unit executes correction of Lq by d-axis electric current Id, by using the equation of Lq(Id, Iq)=Lq(Iq)−K×Id, wherein K is a constant.
4 more elements
Dependencies are inferred from the claim text.