Patent ID: 6674261
Filing Date: 2004-01-06
Classification: B60L,Y02T

Abstract:
A motor control apparatus comprising:a current sensor for detecting a current flowing through an armature of a motor having a salient-pole rotor; a rotational speed sensor for detecting a rotational speed of said motor; an angle sensor for outputting a pulse signal each time a rotor angle of the motor reaches a predetermined angle when the motor is rotated; high-frequency voltage applying means for applying a high-frequency voltage to the armature of the motor; rotor angle detecting means for carrying out a first rotor angle detecting process to apply the high-frequency voltage from said high-frequency voltage applying means to said armature and detect the rotor angle of said motor based on a change in the current detected by said current detector depending on the applied high-frequency voltage when the detected rotational speed of said motor is lower than a predetermined rotational speed, and carrying out a second rotor angle detecting process to detect the rotor angle of said motor based on the pulse signal outputted from said angle sensor when the detected rotational speed of said motor is equal to or higher than said predetermined rotational speed; and energization control means for controlling energization of said armature based on the rotor angle of said motor which is detected by said rotor angle detecting means; said rotor angle detecting means comprising means for sampling the current detected by said current sensor in each given control cycle to detect the rotor angle of said motor in said first rotor angle detecting process, and, when said second rotor angle detecting process changes to said first rotor angle detecting process, detecting the rotor angle finally detected in said second rotor angle detecting process as the rotor angle in a first control cycle of said first rotor angle detecting process, and, in subsequent control cycles, detecting the rotor angle in a present control cycle using the rotor angle detected in a preceding control cycle as a calculation parameter.