| 摘要 |
<P>PROBLEM TO BE SOLVED: To keep a temperature rise resulting from the heating of stator coils or an inverter to the minimum when the rotor of a brushless motor of an electric power steering device is locked. <P>SOLUTION: The brush-less motor which is used as an assistant motor of the electric power steering device is equipped with the three-phase stator coils, a rotation position detecting means which detects the rotation position of the rotor, and the inverter which controls phases of electric currents fed to the stator coils of respective phases from the rotation position of the rotor detected by the rotation position detecting means. Then a steering wheel is held, and a state that the rotor of the brushless motor is locked continues for a specified period of time, if, e.g., a U-phase current Iu is a peak current (refer to A position), the rotation position of the rotor which is outputted by the rotation position detecting means is changed in a direction at 90° of an electrical lead angle, and the U-phase current Iu is reduced from the peak current to 0 (refer to B position). Thus, the strong heating of the stator coil by a continuous flow of the peak current to a specified stator coil can be suppressed. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
