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US 5,493,187 AGranted
Method and apparatus for controlling brushless motor
AssigneeYamamoto Electric Corporation
InventorMasahiko Iijima
Life of this patent
Estimating the term…
Abstract
The rotation speed of a brushless motor is detected to generate a signal synchronizing with the rotation of the motor, and, on the basis of the synchronizing signal, a plurality of duty signals representing respectively different duty factors are generated. One of the plural duty signals is selected according to the detected rotation speed of the motor, and, on the basis of the selected duty signal, a corresponding exciting signal is supplied to the motor. The higher the detected rotation speed of the motor, the selected duty signal represents a larger duty factor.
Claims6
An apparatus for controlling a multi-phase brushless motor, comprising:
- speed detecting means for detecting a rotation speed of said brushless motor:
- Hall sensors, a number of which is same as a phase number of said motor, for generating Hall signals of a duty factor of 1/2 in response to predetermined rotational angles of a rotor of said motor, respectively;
- duty signal generating means for generating at least two kinds of duty signals for each phase of said motor having different duty factors and different lead angles representing different phase angles on the basis of said plurality of Hall signals;
- selecting means for selecting, according to the rotation speed detected by said speed detecting means, one of said two kinds of duty signals for each phase of said motor representing a larger duty factor and a larger lead angle representing an advanced phase angle with an increase of the rotation speed of said motor;
- and
- exciting signal generating means for generating, on the basis of the selected duty signals for the respective phases of said motor, exciting signals for the phases of said motor to be supplied to said motor, respectively, wherein said phase number of said motor is 3, wherein
- said number of said Hall sensors is 3, wherein
- said three Hall sensors generate Hall signals of U-, V- and W-phases, respectively, wherein
- said duty signal generating means generates
- a signal which rises in synchronism with a rising of said U-phase Hall signal and falls in synchronism with a rising of said V-phase Hall signal as a U-phase duty signal with a duty factor of 1/3,
- a signal which rises in synchronism with a rising of said V-phase Hall signal and falls in synchronism with a rising of said W-phase Hall signal as a V-phase duty signal with a duty factor of 1/3,
- a signal which rises in synchronism with a rising of said W-phase Hall signal and falls in synchronism with a rising of said U-phase Hall signal as a W-phase duty signal with a duty factor of 1/3,
- a signal which is a phase inverted signal of said V-phase Hall signal as a U-phase duty signal with a duty factor of 1/2,
- a signal which is a phase inverted signal of said W-phase Hall signal as a V-phase duty signal with a duty factor of 1/2, and
- a signal which is a phase inverted signal of U-phase Hall signal as a W-phase duty signal with a duty factor of 1/2, and wherein
- said selecting means selects said U-, V- and W-phase duty signals with duty factors of 1/3 when the rotation speed of said motor is below said predetermined speed, and selects said U-, V- and W-phase duty signals with duty factors of 1/2 when the rotation speed of said motor is equal to or more than said predetermined speed.
13 more elements
An apparatus for controlling a multi-phase brushless motor, comprising:
- speed detecting means for detecting a rotation speed of said brushless motor;
- first set of Hall sensors, a number of which is same as a phase number of said motor, for generating Hall signals of a duty factor of 1/2 in response to first predetermined rotational angles of a rotor of said motor;
- a second set of Hall sensors, a number of which is the same as the phase number of said motor, for generating Hall signals of a duty factor of 1/3 in response to second predetermined rotational angles of said rotor of said motor, said first set of Hall sensors being shifted from said second set of Hall sensors by a desired angle along a rotational direction of said rotor;
- duty signal generating means for generating at least two kinds of duty signals for each phase of said motor having different duty factors and different lead angles representing different phase angles on the basis of said first and second sets of Hall signals, respectively;
- selecting means for selecting, according to the rotation speed detected by said speed detecting means, one of said two kinds of duty signals for each phase of said motor representing a larger duty factor and a larger lead angle representing an advanced phase angle with an increase of the rotation speed of said motor;
- and
- exciting signal generating means for generating, on the basis of the selected duty signals for the phases of said motor, exciting signals for the phases of said motor to be supplied to said motor, respectively.
4 more elements
Dependencies are inferred from the claim text.