| 摘要 |
PROBLEM TO BE SOLVED: To surely detect a magnetic flux position to perform stable control even with a high load or when the load suddenly changes. SOLUTION: A d-q converter 8 converts a detected current value is into an impedance observation axis positioned at a place shifted 45 degrees from an estimation magnetic flux position θ. A high frequency impedance estimation device 10 estimates high frequency impedances Zdm and Zqm at the two points advanced in electric angle 45 degrees from a γ axis and another point delayed in an electric angle 45 degrees from the γ axis. A magnetic flux position estimation device 11 estimates a first magnetic flux position estimation value θ so as to eliminate deviation in the high frequency impedances Zdm, Zqm. A magnetic flux position correction device 23 inputs current instruction values iγ* and iδ*, estimates a secondary circuit power factor angle θ r being a phase difference between secondary induction electromotive force and secondary current, and subtracts the secondary circuit power factor angle estimation value θ r from the first magnetic flux position estimation value θ to be output as a second magnetic flux position θ c. |
