| 摘要 |
<p>PROBLEM TO BE SOLVED: To aim at provision of a calculating means for estimation value of a correct motor angular speed while restricting generation of a vibratory electric current at the time of returning a handle, in the motor control circuit of an electric motor-driven power steering device in which an H bridge circuit is used. SOLUTION: FET1 is driven at a duty ratio D1 and FET3 is driven at a duty ratio D2 longer than FET1 in view of time. D2 is defined by the primary function of D1, namely D2=a.D+b and if a, b are decided by driving condition, a motor electric current I is displayed by such an equation as I=Vb/ R 1-(KTWret/γVb)}.D+KT/R(ωret-ω) so that a vibratory electric current (noise) can be prevented from its generation. Motor angular speedωcan be estimated from a motor inter-terminal voltage VM=(D1+D2-1)Vb obtained from a battery voltage Vb and a duty ratio D1, D2, and a motor electric current value I estimated from a motor electric current detection value and the second duty ratio.</p> |
