| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of a conventional initial position detection device for a permanent magnet synchronous motor, in which the initial position of a permanent magnet synchronous motor with a small saliency ratio cannot be detected with high resolution. SOLUTION: Six voltage pulses having mutual phase differences in electrical angles of 60 deg. are applied, parallel components and orthogonal components of current responses are calculated, the position of the voltage pulse which gives a largest value in the parallel components is determined as an approximate position, and a correction value is generated according to the orthogonal component at that time. The sum of the approximate position and the corrective value is determined as the initial position. With such a constitution, the initial position of the permanent magnet synchronous motor with the small saliency ratio can be detected with high resolution. Further, the corrective value is restricted within a range of -30 deg. to +30 deg., and the voltage pulse giving the second largest parallel component is confirmed so as to avoid a detection failure. |
