Driving system of AC motor
First Claim
1. A driving system of an AC motor including an inverter which applies an arbitrary alternating current to the AC motor and a controller which transmits control signals to the inverter, the controller including:
- minute voltage applying means which applies a minute voltage change on a dc axis which constitutes an estimation axis of a magnetic flux of the motor, current observation means which observes an electric current which flows to the motor, and polarity discriminating means which discriminates the polarities of magnetic poles of the motor based on positive-side and negative-side current flow times of ripple components contained in the observed value of the electric current obtained by the current observation means.
1 Assignment
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Accused Products
Abstract
The present invention provides a control algorithm which instantaneously detects magnetic pole positions in the inside of a motor including polarities of the motor. A controller 1 applies a minute voltage change vhd to a voltage command on a dc axis which constitutes an estimation magnetic pole axis of the motor 3, detects electric currents Idc, Iqc of a motor 3 and discriminates the polarities of the magnetic pole axes by making use of the difference between a cycle in which ripple components of the electric currents Idc, Iqc become positive and a cycle in which the ripple components become negative or the difference between positive-side and negative-side current change rates. Further, the minute voltage change vhd with respect to the above-mentioned voltage command is generated on both of the dc axis and the qc axis rectangular thereto, and the magnetic pole positions of the motor are directly estimated based on the current ripple components on the respective axes. Without separately providing a cycle for discriminating the polarities of the magnetic poles, the cycle from the turning-on of a power source to the starting of the motor can be shortened so that the high-speed starting of the motor can be realized.
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Citations
21 Claims
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1. A driving system of an AC motor including an inverter which applies an arbitrary alternating current to the AC motor and a controller which transmits control signals to the inverter, the controller including:
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minute voltage applying means which applies a minute voltage change on a dc axis which constitutes an estimation axis of a magnetic flux of the motor, current observation means which observes an electric current which flows to the motor, and polarity discriminating means which discriminates the polarities of magnetic poles of the motor based on positive-side and negative-side current flow times of ripple components contained in the observed value of the electric current obtained by the current observation means. - View Dependent Claims (3, 5, 14, 18)
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2. A driving system of an AC motor including an inverter which applies an arbitrary alternating current to the AC motor and a controller which transmits control signals to the inverter, the controller including:
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minute voltage change applying means which generates a minute voltage change on a dc axis which constitutes an estimation axis of a magnetic flux of the motor, current observation means which observes an electric current which flows to the motor, and polarity discriminating means which discriminates the polarities of magnetic poles of the motor based on the difference between positive-side and negative-side current change rates of ripple components contained in the observed value of the electric current obtained by the current observation means. - View Dependent Claims (4, 6, 12, 15, 19)
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7. A driving system of an AC motor including an inverter which applies an arbitrary alternating current to the AC motor and a controller which transmits control signals to the inverter, the controller including:
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minute voltage change applying means which gives a minute voltage change to a voltage command on a dc axis which constitutes an estimation axis of a magnetic flux of the motor and to a voltage command on a qc axis which is perpendicular to the dc axis, current observation means which observes an electric current which flows to the motor on the dc axis and the qc axis, and magnetic pole position estimating means which, with respect to ripple components contained in a current observed on the dc axis and the qc axis, estimates magnetic pole positions in the inside of the motor based on positive-side and negative-side current flow times of the ripple components. - View Dependent Claims (16, 20)
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8. A driving system of an AC motor including an inverter which applies an arbitrary alternating current to the AC motor and a controller which transmits control signals to the inverter, the controller including:
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minute voltage change applying means which gives a minute voltage change to a voltage command on a dc axis which constitutes an estimation axis of a magnetic flux of the motor and a voltage command on a qc axis which is perpendicular to the dc axis, current observation means which observes an electric current which flows to the motor on the dc axis and the qc axis, and magnetic pole position estimating means which, with respect to ripple components contained in a current observed on the dc axis and the qc axis, detects current change rates of the ripple components separately at positive and negative sides of the ripple components and estimates magnetic pole positions in the inside of the motor based on the difference of the electric current rates. - View Dependent Claims (9, 10, 11, 13, 17, 21)
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Specification