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 upper and lower 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 element, wherein the voltage applied to the motor drive circuit changes based on a number of the upper switching elements that is turned on.
1 Assignment
0 Petitions
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.
-
Citations
11 Claims
-
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 having a plurality of upper and lower 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 element, wherein the voltage applied to the motor drive circuit changes based on a number of the upper switching elements that is turned on. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
Specification