| 摘要 |
<P>PROBLEM TO BE SOLVED: To control a motor by a novel control method without a rotation angle sensor. <P>SOLUTION: A motor is driven based on a γ-axis current value in a γ-δ coordinate system that is an imaginary rotating coordinate system. The γ-δ coordinate system is a coordinate system that rotates in accordance with a control angle θ<SB>C</SB>that is a rotation angle used in control. Assist torque corresponding to a difference (load angle θ<SB>L</SB>) between the control angle θ<SB>C</SB>and a rotor angle θ<SB>M</SB>is generated. Meanwhile, when a detected steering torque T is fed back, an addition angle α is generated to bring the detected steering torque T closer to a command steering torque T*. By adding the addition angle α to an immediately preceding value θ<SB>C</SB>(n-1) of the control angle θ<SB>C</SB>, a current value θ<SB>C</SB>(n) of the control angle θ<SB>C</SB>is obtained. The addition angle α is limited by an addition angle limiter 24. When the detected steering torque T is saturated, an initialization unit 29 initializes the addition angle α, etc. When initialization is performed in response to saturation of the detected steering torque T, an initialization processing is prohibited until an absolute value of the detected steering torque T is equal to or below a predetermined threshold value. <P>COPYRIGHT: (C)2010,JPO&INPIT |
