| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve estimation accuracy in estimating the rotational angle of a rotor on the basis of induced voltage in position sensorless control of a brushless DC motor. <P>SOLUTION: A model operator 50 calculates a sine component Vs and a cosine component Vc of the induced voltage which consists of a sine value sin θe and a cosine value cos θe of an angular difference θe between an estimated rotational angle θ^ and an actual rotational angle θ, relative to the rotating angle of the rotor by the circuit equation of a line voltage model on the basis of respective voltage command values Vu, Vv, Vw outputted from a dq-three phase converter 25 and each phase current Iu, Iw outputted from phase current detecting portions 27, 27. A normalizing part 33 calculates an angular difference approximate value (-Vs/(Vs<SP>2</SP>+Vc<SP>2</SP>)<SP>1/2</SP>≈θe) approximate to the angular difference θe by dividing the sine component Vs of the induced voltage corresponding to a state amount (ωKe), relative to a rotational angular velocity ω calculated on the basis of the sine component Vs and the cosine component Vc, and inputs the angular difference approximate value as an input value of the follow-up arithmetic processing into an observer 17. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
