| 摘要 |
PURPOSE: To obtain a polarity detection method in which the position and the polarity of a magnetic pole for a permanent magnet-type synchronous motor can be detected without using a sensor. CONSTITUTION: The magnetic-flux density of a stator core 3 is concentrate near an inflection Point of magnetization characteristic, a positive pulse voltage and a negative pulse voltage are applied across one-phase windings 4, 5 and other short-circuited two-phase windings 6, 7, 8, 9, and both response currents at a time when pulse phases are transient are found. Then, whether the response currents are in an increase magnetization direction or a decrease magnetization direction is judged, whether positions of permanent magnets 2 faced with the applied windings are in the center of magnetic poles or between the magnetic poles is judged, and whether the magnetic poles faced with the applied phases are N-poles or S-poles in the case of the the magnetic poles can be judged. Thereby, the polarity of magnetic poles of a rotor can be detected without using a sensor. |
