| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electric power steering device not reducing assist torque by performing weak field control even if fluctuation occurs on a voltage Vb of a power source 30. <P>SOLUTION: A d-axis current (field current) Id for performing the weak field control is varied according to the actual voltage Vb of the power source 30. Namely, when the actual number of revolution N of an assist electric motor 60 is larger than a predetermined number of revolution (N1, N2 or the like) varied according to the actual voltage Vb of the power source 30, the weak field control is performed. For example, when the actual voltage Vb of the power source 30 is Vb1, the weak field control is performed when the actual number of revolution N of the assist electric motor 60 is larger than N1. When the actual voltage Vb of the power source 30 is Vb2, the weak field control is performed when the actual number of revolution N of the assist electric motor 60 is larger than N2. <P>COPYRIGHT: (C)2007,JPO&INPIT |
