Motor control apparatus and electric power steering apparatus
First Claim
1. A motor control apparatus that drives a motor with n phases, wherein n is a natural number equal to or larger than 3, the motor control apparatus comprising:
- a controller that determines a level of a command voltage used to drive the motor;
a motor drive signal generator that generates a pulse width modulation signal having a predetermined pulse width in each unit period, using a voltage whose level is equal to the level determined by the controller; and
a motor drive circuit havinga plurality of switching elements that drive the motor based on the pulse width modulation signal from the motor drive signal generator, anda switching circuit that supplies a current to the motor when the pulse width modulation signal turns the plurality of switching elements on/off,wherein the controller corrects the level of the command voltage to compensate for a change in voltage applied to the motor drive circuit in accordance with on/off states of the switching elements.
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Accused Products
Abstract
An angle calculation portion of a motor control apparatus determines an angle θ of a rotor, and an angular velocity calculation portion determines an angular velocity ωe of the rotor. A command current calculation portion determines command currents id* and iq* on dq axes, based on a steering torque T and a vehicle speed S. An open-loop control portion determines command voltages vd and vq on the dq axes based on the command currents id* and iq* and the angular velocity ωe, according to circuit equations of a motor. A dq-axis/three-phase conversion portion converts the command voltages vd and vq to command voltages of three phases. A three-phase voltage correction portion corrects the command voltage so that an actual time average value of a voltage applied to each phase is equal to a time average value of a voltage that is to be applied to the phase if the voltage is not decreased, in order to compensate for a decrease in the applied voltage. By performing the correction, it is possible to eliminate or suppress a decrease in control accuracy due to a wiring resistance and the like.
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Citations
10 Claims
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1. A motor control apparatus that drives a motor with n phases, wherein n is a natural number equal to or larger than 3, the motor control apparatus comprising:
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a controller that determines a level of a command voltage used to drive the motor; a motor drive signal generator that generates a pulse width modulation signal having a predetermined pulse width in each unit period, using a voltage whose level is equal to the level determined by the controller; and a motor drive circuit having a plurality of switching elements that drive the motor based on the pulse width modulation signal from the motor drive signal generator, and a switching circuit that supplies a current to the motor when the pulse width modulation signal turns the plurality of switching elements on/off, wherein the controller corrects the level of the command voltage to compensate for a change in voltage applied to the motor drive circuit in accordance with on/off states of the switching elements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification