MOTOR CONTROLLER AND ELECTRIC POWER STEERING APPARATUS

• US 20090079371A1
• Filed: 09/12/2008
• Published: 03/26/2009
• Est. Priority Date: 09/26/2007
• Status: Active Grant

• Current Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Original Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Inventors: Suzuki, Hiroshi
• Granted Patent: US 8,008,880 B2
• Time in Patent Office: Days
• US Class Current: 318/400.20
• CPC Class Codes: H02P 21/16 Estimation of constants, e.g. the rotor time constant
• CPC Class Codes: H02P 29/0241 the fault being an overvoltage

Abstract

A signal generating section includes a second calculating section that corrects phase resistance. The calculating section stores resistance values of phases that have been measured in advance and a reference resistance value. The calculating section calculates correction components, which cancel a voltage drop term of a voltage equation of a d-q coordinate system changing depending on the rotation angle of the motor, based on the stored resistance values and the reference resistance value. The signal generating section superimposes the correction component and the correction component on a d-axis voltage command value and a q-axis voltage command value, respectively. The d-axis voltage command value and the q-axis voltage command value are thus corrected in such a manner as to suppress a torque ripple caused by difference among the resistance values of the phases.

Claims

1. A motor controller having signal generating means that generates a motor control signal by performing an electric current feedback control in a d-q coordinate system, and a driver circuit that supplies a drive power of three phases to a motor based on the motor control signal, the motor controller comprising:

memory means that stores a resistance value of each one of the phases of the motor,

wherein the signal generating means corrects respective voltage command values of the d-q coordinate system based on the stored resistance values in such a manner as to suppress a torque ripple caused by a difference among the resistance values.

2. The motor controller according to claim 1, wherein each one of the voltage command values of the d-q coordinate system is corrected by superimposing a correction component that cancels a voltage drop term of a voltage equation of the d-q coordinate system, the voltage drop term changing depending on a rotation angle of the motor.

3. The motor controller according to claim 1, wherein each one of the resistance values of the phases stored in the memory means is a resistance value of a power supply line including a power cable connecting the motor to the driver circuit and a phase opening relay arranged in the power cable, the resistance value having been measured in advance for each of the phases.

4. An electric power steering apparatus comprising the motor controller according to claim 1.