| 摘要 |
<p>PURPOSE: To surely prevent an electric motor from abnormal heating and the like by providing a limiting means limiting the maximum value of a control signal according to the integrating value of the absolute value of the control signal. CONSTITUTION: A control signal driving a motor 12 based on the steering torque detected by a torque sensor 3 is formed by means of a microcomputer 21, and an H bridge circuit 40 is operated based on this so as to control the current carrying direction and the current carrying quantity to the motor 12. Namely, by limiting the maximum value of the control signal according to the integrating value of the absolute value of the control signal to a motor drive circuit 30, for example, by limiting the control signal to be small in the case of the large integrating value of the absolute value of the control signal, or by enlarging the maximum value of the control signal reversely in the case of the small integrating value, the maximum value of the control signal is limited according to the integrating value of the control signal even in the case of the large steering torque and large current carrying to the motor 12. Consequently, generation of abnormality such as abnormal heating of the motor 12 following continuous large current flow can be surely prevented.</p> |
